EMULSIONS AND SHE EFFECT OF HYDEOGEN ION CONCENTRATION UPON TH EIR S T A B I L I T Y . By - JOHN C^KRANTZ, JH. LI B R A R Y , UNIVERSITY OF M A R Y L A N D Thes i s submi tt ed to the Facu l ty of the of the u n i v . e r s i t y of Maryland in part of the requirements f o r the degree o Ph i lo so ph y . 1928. Graduate School a l f u l f i l l m e n t D o c to r of 46522 UMI Number: DP70056 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. Dissertation Publishing UMI DP70056 Published by ProQuest LLC (2015). Copyright in the Dissertation held by the Author. Microform Edition © ProQuest LLC. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106- 1346 ProOuest ACKNOWLEDGMENT The w r i t e r wi shes to expres s h i s a p p r e c i a t i o n and thanKs to Dr* K e l l B. Gordon, Head of the Department o f Chemistry of the U n i v e r s i t y of Maryland f or many h e l p f u l s u g g e s t i o n s during the course of t h i s i n v e s t i g a t i o n . TABLE OF COUTMTS. E m u ls io n s and E f f e c t o f H ydrogen I o n C o n c e n t r a t i o n Upon t h e i r S t a b i l i t y * I . I n t r o d u c t i o n I I . E x p e r im e n ta l 1 . M a t e r i a l s and A p p a ra tu s* 2 . C e r t a i n O l e a t e s as. E m u ls i f y in g A g e n ts . 3 . T a l e r a t e s a s E m u l s i f y in g A g e n ts . 4 . A r a b a t e s a s E m u l s i f y i n g A g e n ts . 5 . Compounds R e l a t e d to A ra b ic A c id a s E m u ls i fy in g A g e n t s . 6 . M ethod o f S tu d y o f t h e I n f l u e n c e o f H ydrogen I o n C o n c e n t r a t i o n upon G i l - i n - W a t e r E m u ls io n s . 7 . O b s e r v a t io n s u p on th e Changes o f Prr i n O i l - i n - W a t e r Em ulsi ons . 8 . S tu d y o f th e P h y s i c a l P r o p e r t i e s o f t h e E m u ls io n s . {011 - i a - W a t e r ) . 9* M ethod o f S tu d y o f th e I n f l u e n c e o f H ydrogen I o n C o n c e n t r a t i o n upon W ater—i n - O i l E m u ls io n s . 1 0 . O b s e r v a t io n s upon th e Changes o f p__ i n W a t e r - i n - O i l Emulsi o n s . 1 1 . S tu d y o f th e P h y s i c a l P r o p e r t i e s o f th e E m u ls io n s ( W a t e r - i n - O i l ) . I I I . Summary o f R e s u l t s and T h e o r e t i c a l C o n s i d e r a t i o n s . I T . C o n c lu s i ons . T . B i b l i o g r a p h y . E m u ls io n s and Hie E f f e c t o f H ydrogen I o n C o n c e n t r a t i o n upon t h e i r S t a b i l i t y . I n t r o d u c t i o n . S in c e th e p u b l i c a t i o n o f th e w ork o f H a r k in s (1) and L angm uir ( 2 ) on th e s t r u c t u r e o f l i q u i d s u r f a c e s a t a l i q u i d - l i q u i d s u r f a c e , th e o r i e n t a t i o n t h e o r y o f e m u ls io n s and e m u l s i - f i c a t i o n h a s b e e n t h e o b j e c t o f much i n v e s t i g a t i o n and e x ­ p e r i m e n t a l w o rk . Newman (3) w o rk in g w i th B a n c r o f t i n 1914 o b s e r v e d t h a t when b e n z e n e and w a te r w ere e m u l s i f i e d u s i n g sodium o l e a t e a s th e e m u l s i f y i n g a g e n t th e h y d ro c a r b o n fo rm ed th e i n n e r p h a s e , w h e re a s when o l e i c a c i d s a l t s o f m e t a l s w i th a h i g h e r v a le n c e a s m agnesium o l e a t e w ere em ployed , th e w a te r becom es d i s p e r s e d t h r u t h e b e n z e n e , t h e l a t t e r becom ing th e c o n t in u o u s p h a s e . These o b s e r v a t i o n s were s u b s t a n t i a t e d by H a r k in s and a r e i n a c c o rd w i th h i s t h e o r e t i c a l d e d u c t io n s o f t h e n a t u r e o f e m u l s i f y i n g a g e n t s . H a rk in s and h i s c o -w o r k e r s b e l i e v e t h a t t h e s t a b i l i t y o f th e d i s p e r s e d p a r t i c l e s i n an a n u l s i o n i s a c c o m p l ish e d by th e o r i e n t a t i o n o f th e m o le c u le s a t th e i n t e r f a c e w i th th e medium o f d i s p e r s i o n . An e m u l s i f y i n g a g e n t i n t h e l i g h t o f H a r k i n f s t h e o r y s h o u ld be a compound h a v in g a p o l a r and n on ­ p o l a r g roup i n th e m o le c u l e . Hence th e a l k a l i s a l t o f a f a t t y a c i d such a s o l e i c and s t e a r i c a c i d s m ee t t h i s r e q u i r e m e n t . As e m u ls io n s a r e sy s te m s o f two n o n - s o l u b l e l i q u i d s , th e e m u l s i f y i n g a g e n t m ust s e r v e t o r e d u c e th e a b r u p t n e s s o f t h e t r a n s i t i o n b e tw e e n th e two l i q u i d s . An o n u l s i o n , a c c o r d in g t o H a r k i n s , i s s t a b l e when th e m o le c u le s o f t h e f i l m o f th e e m u l s i f y i n g a g e n t f i t t h e c u r v a t u r e o f t h e e m u l s i f i e d p a r t i c l e . A c c o r d in g ly , sod ium o l e a t e r e d u c e s th e f r e e e n e r g y b e tw ee n b e n z e n e and w a t e r and th u s i n d u c e s t h e e m u l s i f i c a t i o n o f th e b e n z e n e i n t h e w a t e r , w h e rea s w i th m agnesium o l e a t e th e f i l m o f t h e e m u l s i f y i n g a g e n t f i t s b e t t e r th e w a t e r p a r t i c l e and t h i s i n t u r n becom es d i s p e r s e d i n b e n z e n e . I n th e p r e p a r a t i o n o f m e d i c i n a l e m u ls io n s gum a r a b i c o r a c a c i a i s t h e m ost g e n e r a l l y u s e d e m u l s i f y i n g a g e n t and y i e l d s v e r y s t a b l e m i l k - l i k e e m u l s i o n s . A c a c ia i n a l l o f th e g e n e r a l l y u se d m e d i c i n a l e m u ls io n s i n v a r i a b l y p r o d u c e s an e m u ls io n o f t h e o i l - i n - w a t e r ty p e and a s t h i s ty p e o f e m u ls io n s i s th e more p a l a t a b l e , t h i s gum s e r v e s w e l l f o r t h e p r e p a r a t i o n o f m e d i c i n a l e m u ls io n s . I n g e n e r a l t r e a t i s e s on M a t e r i a M edica and M e d ic in a l C h e m is t ry t h i s gum i s r e f e r r e d to a s th e sod ium , p o t a s s iu m and c a lc iu m s a l t s o f a r a b i c a c id * The g e n e r a l t e x t s on pharm acy and p h a r m a c e u t i c a l c h e m is t r y have a s s i g n e d th e f o l l o w i n g f o r m u la s t o t h i s compound a r a b i c a c i d . 2{C6H1 0 Or ) H_0 (4 ) C12H2?0 (5) and (7) 12 22 11 ( 6 ) The gum i t s e l f c o n t a i n s v a r y i n g am ounts o f sodium and p o ta s s iu m and c e r t a i n sa m p le s a r e p r a c t i c a l l y p u r e c a lc iu m a r a b a t e . Hot much work h a s been done on t h e d e t e r m i n a t i o n o f t h e s t r u c t u r e o f a r a b i c a c i d and B e i l s t e i n g i v e s th e f o l lo w in g e m p i r i c a l , f o rm u la f o r t h e a c i d w h ich h a s b een d r i e d a t 1 0 0 ° C. - 2 - C1 QH1 8 0 g? ITeubauer ( 8 ) p r e p a r e d t h e c a l c i u m and p o t a s s i u m s a l t s and found them to h av e t h e f o l l o w i n g c o m p o s i t io n s CaO. 2C12H 0 ^ K2 0 * (g12H2 2 ° i i ) 3 ^ H eckm eyer (9 ) fo und th e l e a d , c o p p e r and b a r iu m s a l t s t o have th e follovnLng c o m p o s i t io n s 2Pb0.3C12H20Ol o Cu0 .C 12H200 1 0 .C12H220 i i BaO.£C12H20O10 • O 'S u l l i v a n (10) p r e p a r e d c a lc iu m and b a r iu m s a l t s o f t h e a c i d w h ich he a n a ly z e d and a s s i g n e d t o th a n th e f o l l o w i n g f o rm u la s CQ 9^-142° 7 4 *Ga annate (15 ) - p r e p a r e d by h y d r o l y z i n g l a c t o s e w i t h d i l u t e d s u l p h u r i c a c i d , rem o v in g t h e s u l p h u r i c a c i d by t h e a d d i t i o n o f b a r iu m h y d r o x id e and o x i d i z i n g t h e f i l t r a t e w i t h b ro m ine a t room te m p e r a tu r e * The h y d ro g en b rom ide was rem oved by means o f l e a d c a r b o n a te and s i l v e r o x id e and th e l e a d and s i l v e r rem oved by h y d ro g en s u l p h i d e . The f r e e a c i d was n e u t r a l i z e d w i th cadmium c a r b o n a t e and e v a p o r a t e d t o d r y n e s s . The sod ium s a l t was p r e p a r e d by n e u t r a l i z a t i o n o f t h e f r e e a c i d w i th sodium c a r b o n a t e . 1 2 . Magnesium D i o x y s t e a r a t e (16) - p r e p a r e d by th e o x id a ­ t i o n o f p o ta s s iu m o l e a t e i n a l k a l i n e s o l u t i o n by means o f p o t a s s i u m p e rm a n g an a te * The a c i d was p r e c i p i t a t e d and p u r i f i e d by c r y s t a l l i z a t i o n fro m a l c o h o l . The sodium s a l t was p r e p a r e d by th e a d d i t i o n o f a m o le c u la r e q u i v a l e n t o f sod ium h y d ro x id e and t h e m agnesium s a l t o b t a i n e d by d o u b le d e c o m p o s i t io n b e tw een m agnesium c h l o r i d e and sodium d i o x y s t e a r a t e . 13* C a lc ium S a l i c y l a t e and C a lc iu m G a l l a t e - t h e s e s u b s t a n c e s w ere p r e p a r e d by n e u t r a l i z a t i o n o f th e f r e e a c i d s o f a h ig h d e g re e o f p u r i t y by m eans o f c a lc iu m c a r b o n a t e and c r y s t a l l i z i n g th e s a l t s from w a te r* 14* The a c a c i a and t r a g a c a n t h em ployed m et t h e r e q u i r e m e n t s p r e s c r i b e d by t h e U n i te d S t a t e s P h a rm a c o p o e ia f o r t h e s e s u b s t a n c e s . 1 5 . The m i n e r a l o i l em ployed was th e c o m m e rc ia l ,TN u jo l" and t h e c o t t o n s e e d and o l i v e o i l s met t h e r e q u i r e m e n t s o f t h e U n i te d S t a t e s P h a rm a c o p o e ia . D i s t i l l e d W ater P^- 5 .8 t o 6*4 was employed* 16*. A p p a ra tu s - The s p e c i a l a p p a r a t u s em ployed i n t h i s i n v e s t i g a t i o n c o n s i s t e d o f a h y d ro g e n i o n d e t e r m i n a t i o n o u t f i t w i th a ty p e K. p o t e n t i o m e t e r and a W ilson h y d ro g e n e l e c t r o d e , a Du Nofly T e n s io m e te r and a Donnam p i p e t t e w h ich i s shown i n f i g u r e t h i r t e e n . < C e r t a i n O le a t e s a s E m u ls i f y in g A g e n ts : I n a l ig n m e n t w i th t h e w ork o f H a r k in s and Uewman s e v e r a l e m u ls io n s w ere p r e p a r e d o f m in e r a l o i l u s in g sodium o l e a t e , m agnesium o l e a t e , c a lc iu m o l e a t e , m anganese o l e a t e , c o b a l t o u s o l e a t e , n i c k e l o u s o l e a t e and alum inum o l e a t e a s e m u l s i f y in g a g e n t s * S i m i l a r to th e o b s e r v a t i o n s o f Uewman and H a rk in s w i th b e n z e n e , th e sodium o l e a t e y i e l d e d a d i s p e r s i o n o f o i l i n w a t e r , w h e rea s the d i s p e r s i o n p r e p a r e d w i th t h e o l e a t e s o f th e d i v a l e n t m e t a l s and alum inum gave e m u ls io n s o f th e wat e r - i n - o i l t y p e . When sodium o l e a t e was em ployed one gram o f t h e s a l t was s u f f i c i e n t to y i e l d 40 c c . o f a s t a b l e o i l - i n - w a te r e m u ls io n 25 p e r c e n t* The m ethod em ployed c o n s i s t e d o f t r i t u r a t i n g th e o i l t h o r o u g h ly w i th t h e sod ium o l e a t e and a d d in g 6 cc* o f w a t e r , i n one p o r t io n and t r i t u r a t i n g r a p i d l y u n t i l c o m p le te e m u l s i f i c a t i o n t o o k p l a c e ; th e r e m a in d e r o f th e w a t e r was ad d ed s lo w ly w i t h c o n t in u e d t r i t u r a t i o n * I n each c a s e when an e m u ls io n was p r e p a r e d by t h i s m ethod d i l u t i o n w i t h w a te r d id n o t c a u se a s e p a r a t i o n , b u t a t t e m p t s t o d i l u t e w i th o i l f a i l e d , i l l u s t r a t i n g th e p r e s e n c e o f t h e o i l a s t h e i n n e r p h a s e o f th e e m u ls io n * W ith m agnesium o l e a t e th e f o l l o w in g p r o c e d u r e was em ployed* One gram o f m agnesium o l e a t e was t r i t u r a t e d w i th 18 cc* o f o i l and when th e m ix t u r e was hom ogeneous, th e 1 0 cc* o f w a te r was added i n one p o r t i o n w i t h c o n t in u o u s t r i t u r a t i o n * The f o r m a t io n o f th e e m u ls io n n u c l e u s was e a s i l y d e te r m in e d by th e c r a c k l i n g sound p ro d u c e d when t h e p e s t l e was r a p i d l y draw n t h r u t h e em u ls io n * T h is e m u ls io n n u c l e u s was th e n s lo w ly d i l u t e d to 40 cc* w i t h m in e r a l o i l * T h is same p r o c e d u r e was em ployed i n th e p r e p a r a t i o n o f t h e e m u ls io n s p r e p a r e d w i th c a l c iu m , m an g an ese , c o b a l t , n i c k e l and alum inum o l e a t e s * T hese e m u ls io n s w ere p e rm a n e n t o v e r a p e r i o d o f s e v e r a l m onths an d p e r m i t t e d l i b e r a l a d m ix tu re w i th o i l , b u t a t t e m p t s to d i l u t e w i th w a te r b ro u g h t a b o u t immedi a te s e p a r a t i o n . T h is showed t h e o i l to be th e o u t e r p h a s e o f th e e m u ls io n . T hose p r e p a r e d w i th m agnesium o l e a t e were th e m ost e a s i l y p r e p a r e d and th e m ost s t a b l e e m u ls io n s o f th e group* F i g u r e one i l l u s t r a t e s th e b e h a v io r o f t h e s e e m u ls io n s when d i l u t i o n was a t t e m p te d w i th w a t e r and o i l r e s p e c t i v e l y . • 10 Emulsion §1 Emulsion #2 Emulsion #3 Emulsion #4 Emulsion #5 Emulsion //6 F ig u r e I . - o i l - i n - w a t e r ty p e w ith sodium o l e a t e . - o i l - i n - w a t e r type with w ate r so lu b le f l u o r e s c e i n dye - showing c o n t i n u i t y o f the co lo r and o u te r phase . - w a t e r - i n - o i l type w ith magnesium o le a t e as the em uls i fy ing a g e n t . - shows 30 cc . of emulsion §3 to which 10 cc . of w ate r has been added - no te the s e p a r a t i o n of the v/ater as a l a y e r beneath the em uls ion . • w a t e r - i n - o i l type - the r ra ter co lo red w i th a f l u o r e s c e i n dye - no te the d i s c o n t i n u i t y of t h e c o lo r . - w a t e r - i n - o i l type a f t e r an a t tem p t to d i l u t e with w a te r to which a f l u o r e s c e i n dye has been added* V a l e r a t e s a s E m u l s i f y in g A gents* C o n s id e r in g th e s i m p l e s t f o m u l a a s s i g n e d t o a r a b l e a c i d C5&j_q0 ^ f i v e c a rb o n a tom s p r e s e n t i n th e m o le c u l e , an a c i d o f t h e m e th an e s e r i e s w i th 5 c a rb o n atom s i n t h e m o le c u le was s e l e c t e d f o r s tu d y * T h is compound v a l e r i c a c i d i s o f d e f i n i t e c o m p o s i t io n and gave an e x c e l l e n t s t a r t i n g p o i n t f o r s tu d y * E m u ls io n s o f m i n e r a l o i l p r e p a r e d w i t h t h e sodium and ammonium s a l t s o f t h i s a c i d w ere o f t h e o i l - i n - w a t e r ty p e and p e r m i t t e d s l i g h t d i l u t i o n w i th w a t e r , b u t c o u ld n o t be d i l u t e d w i th o i l a t a l l . The p r o c e d u r e em ployed was to p l a c e 1 Gm. o f th e s a l t i n a m o r ta r and add 5 c c . o f o i l and 5 c c . o f w a t e r and t r i t u r a t e b r i s k l y u n t i l t h e m ix tu r e was ho m o g en eo u s . ' T h ese e m u ls io n s w ere n o t v e r y s t a b l e , and upon s t a n d i n g 12 t o 18 h o u r s th e o i l and w a te r s e p a r a t e d , y e t upon a g i t a t i o n th e o i l was a g a in d i s p e r s e d t h r u th e w a te r* The m agnesium and z in c s a l t s o f v a l e r i c a c i d , u s i n g th e same q u a n t i t i e s and p r o c e d u r e a s d i r e c t e d i n t h e f o r e g o i n g e x p e r im e n t , y i e l d e d e m u ls io n s o f th e w a te r i n o i l t y p e . As th e s a l t s o f v a l e r i c a c id were fo u n d t o p o s s e s s f a r l e s s e m u l s i f y i n g pow er th a n th e s a l t s o f o l e i c a c i d , more d i f f i c u l t y was e x ­ p e r i e n c e d i n d e t e r m i n i n g w h e th e r th e e m u ls io n was o f th e o i l i n w a te r ty p e o r v i c e v e r s a . I n o r d e r to overcom e t h i s d i f f i c u l t y th e w a te r was c o l o r e d s l i g h t l y by an o r g a n ic p i g ­ m ent c u d b e a r , Yrtiich i s i n s o l u b l e i n th e o i l . The c o n t i n u i t y o f t h i s p ig m e n t i n th e e m u ls io n i n d i c a t e d t h a t w a te r was th e o u t e r o r c o n t in u o u s p h a s e , w h e re a s th e d i s c o n t i n u i t y o f th e r e d c o l o r showed t h a t th e w a te r was d i s p e r s e d i n th e o i l . A r a b a t e s a s E m u ls i f y in g A gents* H av ing d e m o n s t r a te d t h e c a p a c i t y o f d i v a l e n t m e t a l s when com bined w i th th e f i v e c a rb o n atom v a l e r i c a c i d t o fo rm w a t e r - i n - o i l a v u l s i o n s , s e v e r a l e m u ls io n s w ere p r e ­ p a r e d u s in g d i f f e r e n t s a l t s o f a r a b i c a c i d , A ra b ic a c i d , sod ium and m agnesium a r a b a t e s gave s t a b l e e m u ls io n s o f t h e o i l - i n - w a t e r type*. The p r o c e d u r e em ployed was to t r i t u r a t e 10 cc* o f t h e o i l w i th 2*5 ftm* o f th e e m u l s i f y i n g a g e n t and add i n one p o r t i o n 5 c c . o f w a t e r , t h e n a f t e r b r i s k t r i t u r a ­ t i o n and th e f o r m a t i o n o f t h e e m u ls io n n u c l e u s , th e r e m a in d e r o f th e w a te r was added s lo w ly w i th c o n t i n u e d t r i t u r a t i o n u n t i l 40 cc* volume was o b ta in e d * Thus i n e a c h c a s e a 25$ o i l i n w a te r e m u ls io n was p r e p a r e d . The i r o n g e l p r e p a r e d w i th a r a b i c a c i d gave an e m u ls io n o f t h e o i l - i n - w a t e r t y p e , by u s i n g 15 Gm. o f th e g e l , 5 cc* o f w a t e r and 10 c c . o f o i l and b r i s k l y t r i t u r a t ­ i n g u n t i l e m u l s i f i c a t i o n o c c u r r e d . T h is t h e n was d i l u t e d w i th w a te r u n t i l 40 cc* was o b t a in e d * These e m u ls io n s w ere s t a b l e o v e r s e v e r a l w eeks b u t s e p a r a t e d a cream y l a y e r upon th e s u r f a c e a s do t y p i c a l e m u ls io n s p r e p a r e d w i t h gum a r a b i c . With l e a d a r a b a t e a s an e m u l s i f y in g a g e n t , t h e 011 c o u ld n o t be e m u l s i f i e d i n w a t e r , and l i k e w i s e i t was i m p o s s i b l e to p r e p a r e an i n v e r t e d e m u ls io n u s i n g t h i s e m u l s i f y ­ i n g a g e n t* When 1*5 Gm* o f t h e s a l t was b r i s k l y t r i t u r a t e d w i th 5 c c . o f o i l and 5 c c . o f w a t e r , t h e o i l q u i c k l y s e p a r a t e d to th e s u r f a c e o f th e m i x t u r e . Lead a r a b a t e was p r a c t i c a l l y i n s o l u b l e i n w a te r and i n o i l . T hese e x p e r im e n t s i n d i c a t e t h a t a l t h o u g h t h e m agne­ sium and z in c s a l t s o f v a l e r i c a c i d y i e l d e m u ls io n s o f th e w a t e r - i n - o i l t y p e , th e m agnesium and i r o n s a l t s o f a r a b i c a c i d gave t h e n o rm a l o i l - i n - w a t e r em u ls io n * Compounds R e la t e d to A ra b ic A c id a s r f a u l s i f y i n g A g e n ts . H aving shown t h a t th e d i v a l e n t and t r i v a l e n t s a l t s o f a r a b i c a c i d p ro d u c e e m u ls io n s o f th e o i l - i n - w a t e r t y p e , th e n e x t s t e p i n e x p e r i m e n t a l work was to s e l e c t a number o f a c i d s o f d e f i n i t e s t r u c t u r e h a v in g h y d r o x y l g ro u p s i n th e m o le c u le and d e te im in e t h e n a t u r e o f th e e m u ls io n s p r e p a r e d w i th t h e i r d i v a l e n t s a l t s * The s a l t s o f th e f o l lo w in g a c i d s w ere em ployed : OH. CHg ( CH . OH) 4 . C 0 OH i - G a l a c t o n i c Acid a m ix tu r e o f d and I - G a l a c t o n i c a c i d s . QH.CH„(CH.0H) .CGOIi d -G lu c o n ic A c id . C H ( C H g ) 7 . C H . 0H . C H . 0H . ( C H 2 ) v . C 00H D i h y d r o x y s t e a r i c Acid COOH (1) / C H 6 4 OH (2) S a l i c y l i c A cid - 14 G a l l i c A c id The sodium s a l t s and a l s o a s a l t of a d i v a l e n t m e ta l were p re p a red frcm each of th e s e a c id s and when employed as em u ls i fy in g agen ts th e fo l lo w in g o b s e rv a t io n s were made# 1# Gluconic Acid# The sodium s a l t of g lucon ic ac id l i k e the sodium s a l t of v a l e r i c a c id produced emulsions w ith o i l of the o i l - i n - w a t e r type# Five grams of the compound were n e c e s s a r y to d i s p e r s e 10 cc . o f o i l t h r u 10 cc* of w a te r , y i e l d i n g an an u l s io n Yirhich was very v i s c i d y e t upon s tan d in g f o r a pe r iod of an hour began to s e p a r a t e . The ca lc ium s a l t of g lucon ic ac id was t r e a t e d in the fo l lo w in g manner: One gram of th e s a l t was rubbed w i th 5 cc* of o i l , and w a te r was g r a d u a l ly added w ith b r i s k t r i t u r a ­ t i o n . (5 cc# of water i n a l l ) . An emulsion of the w a t e r - i n - o i l type was o b ta in e d . A m ic roscop ic exam inat ion of the a n u l s io n showed the p a r t i c l e s of water to be r a t h e r l a r g e , ye t the emulsion was v isco u s and s t a b le over a p e r io d of s e v e r a l weeks. R evers ing the procedure of mixing and employing the same em u ls i fy in g ag en t , an emulsion was o b ta ined o f the o i l - i n - w ate r ty p e . The p a r t i c l e s of o i l e m u ls i f ie d were l i k e the p a r t i c l e s of th e w ate r i n the p re v io u s experim ent , some­ what l a r g e r t h a n those found i n most a n u l s io n s . Upon s ta n d - i n g t h e o i l and w a te r s e p a ra te d . , b u t n o t c o m p le t e ly and e v id e n c e o f an e m u ls io n n u c le u s r e m a in in g p e rm a n e n t was shown by th e f a c t t h a t upon sim ple, a g i t a t i o n , th e e m u ls io n was r e s t o r e d t o i t s n o im a l c o n d i t i o n . I t i s o f s p e c i a l i n t e r e s t , to n o te t h e v a lu e o f v i s c o s i t y i n d e t e r m i n i n g th e p h a s e s o f e m u ls io n s o f t h i s t y p e ; t h o s e i n w h ich th e v i s c o u s m in e r a l o i l was t h e e x t e r n a l p h a s e were q u i t e v i s c o u s , w h e re a s t h o s e i n w hich th e o i l fo rm ed t h e i n n e r p h a s e had a low v i s c o s i t y . 2 . i - G a l a c t o n i c A c id . The sod ium s a l t o f i - g a l a c t o n i c a c i d , l i k e th e sod ium s a l t o f g l u c o n i c a c id , p ro d u c e d d i s p e r s i o n s o f t h e o i l - i n - w a t e r t y p e , w h e rea s th e c a d ­ mium s a l t o f t h i s con pou nd , l i k e th e c a lc iu m s a l t o f g l u c o n i c e x h i b i t e d th e c a p a c i ty o f d i s p e r s i n g o i l -in w a te r o r w a te r - i n - o i l . E f f o r t s w ere made to p r e p a r e th e alum inum and f e r r i c compounds o f g lu c o n ic and i - g a l a c t o n i c a c i d s , b u t n e i t h e r o f t h e s e a c i d s would com bine w i th alum inum o r t r i v a l e n t i r o n . 3 . D i o x y s t e a r i c A c id . H aving o b s e rv e d th e c a p a c i t y o f each of t h e s e a c i d s to fo rm o i l - i n - w a t e r and w a t e r - i n - o i l e m u ls io n s , t h e n e x t compound p r e p a r e d and s t u d i e d was d i h y d r o x y s t e a r i c a c i d , which h a s b u t two h y d ro x y l g ro u p s i n a m o le c u le c o n t a i n - i n f a c h a i n o f s e v e n te e n c a rb o n a to m s . The sodium s a l t o f d i h y d r o x y s t e a r i c a c i d p ro d u c e d v e r y s t a b l e e m u ls io n o f th e o i l - i n - w a t e r t y p e , w h e reas t h e magnesium s a l t o f t h i s a c id p ro d u c e d e m u ls io n s o f th e w a t e r - i n - o i l t y p e . Under no - 16 c i r c u m s ta n c e s was i t found p o s s i b l e to p r e p a r e e m u ls io n s w i th magnesium d i o x y s t e a r a t e o f t h e o i l - i n - w a t e r t y p e . Thus th e d i h y d r o x y l a c i d com bined w i th a d i v a l e n t m e t a l b e h a v e d l i k e a n o rm a l s t e a r i c a c i d s a l t , w h e re a s t h e p o l y ­ h y d r o x y l compounds i - g a l a c t o n i c a n d g l u c o n i c a c i d showed th e u n u s u a l p r o p e r t y o f e m u l s i f y i n g w a t e r i n o i l and a l s o o i l i n w a t e r . 4 . S a l i c y l i c A c id . H av ing o b s e r v e d th e i n f l u e n c e o f h y d r o x y l g r o u p s i n th e s t r a i g h t c h a in a c i d s , t h e n e x t s t e p was to s t u d y th e i n f l u e n c e o f the i n t r o d u c t i o n o f h y d r o x y l g ro u p s i n t o a c i d s c o n t a i n i n g c y c l i c g r o u p s . A c c o r d in g ly sod ium s a l i c y l a t e was found to p ro d u c e e m u ls io n s w hich w ere u n s t a b l e , b u t a lw a y s o f t h e o i l - i n - w a t e r t y p e . C a lc ium s a l i c y l a t e o n t h e o t h e r hand p ro d u c e d r a t h e r s t a b l e em ul­ s i o n s o f w a te r i n o i l , a l t h o u g h th e w a te r p a r t i c l e s were q u i t e l a r g e . E m ploy ing t h e p r o c e d u r e s d e s c r i b e d u n d e r th e g lu c o n i c a c i d s a l t s , a t t e m p t s w ere made t o p r e p a r e e m u ls io n s o f t h e o i l - i n - w a t e r ty p e and a l th o u g h t h e p a r t i c l e s o f o i l w ere e x c e e d i n g ly l a r g e and r a p i d l y s e p a r a t e d , t h e r e i s u n d o u b te d ly some t e n d e n c y on th e p a r t , o f c a lc iu m s a l i c y l a t e t o fo rm e m u ls io n s o f th e o i l - i n - w a t e r t y p e . 5 . G a l l i c A c id . The sodium s a l t o f g a l l i c a c i d , a l th o u g h a p o o r e m u l s i f y i n g a g e n t , was shown t o i n v a r i a b l y p ro d u c e d i s p e r s i o n s o f t h e o i l - i n - w a t e r t y p e . The c a lc iu m s a l t o f g a l l i c a c i d p ro d u c e d r a t h e r s t a b l e e m u ls io n s o f th e w a t e r - i n - o i l ty p e and a l s o s e rv e d , t o a g r e a t e r d e g re e t h a n d id c a l c iu m s a l i c y l a t e , t o p ro d u c e e m u ls io n s o f th e o i l - i n - w a t e r t y p e . From th e o b s e r v a t i o n s made w i th g lu c o n ic and i - g a l a c - t o n i c a c i d s i n th e fo rm o f t h e i r d i v a l e n t s a l t s , t h i s i s t h e b e h a v i o r t h a t m ig h t hav e b e en a n t i c i p a t e d . 18 - T ab le I* Summary o f R e s u l t s . E m u l s i f y i n g A gent Type o f E m u ls io n Di 1 - i n - f a t e r imp h o t e r i c p r o p e r t i e s 'fa t e r - i n - O i l sod ium o l e a t e X m agnesium o l e a t e X c a lc iu m o l e a t e X c o b a l to u s o l e a t e X n i c h e l o u s o l e a t e X m anganese o l e a t e X alum inum o l e a t e X a r a b i c a c i d X sod ium a r a b a t e X m agnesium a r a b a t e X f e r r i c a r a b a t e X ammonium v a l e r a t e X sodium v a l e r a t e X m agnesium v a l e r a t e X z i n c v a l e r a t e X sodium g l u c o n a te X c a lc iu m g l u c o n a te X sodium i - g a l a c t o n a t e X cadmium i - g a l a c t o n a t e X sodium d i h y d r o x y s t e a r a t e X m agnesium d i h y d r o x y s t e a r a t e X sQdium s a l i c y l a t e X c a lc iu m s a l i c y l a t e X sod ium g a l l a t e X c a lc iu m g a l l a t e X l e a d a r a b a t e d i d n o t s e r v e a s an e m u l s i f y i n g a g e n t . T a b le I i n d i c a t e s t h a t th e s im p le h y d r o c a rb o n c h a in a c i d s when a t t a c h e d to a u n i v a l e n t m e t a l p ro d u c e e m u ls io n s o f th e o i l - i n - w a t e r ty p e and i n v e r t e d e m u ls io n s when th e m e t a l l i c i o n i s d i v a l e n t o r t r i v a l e n t * When, h o w ev er , p o l a r h y d r o x y l g ro u p s a r e i n t r o d u c e d i n t o t h e m o le c u l e , t h i s c o n d i t i o n d o e s n o t h o ld a s i n d i c a t e d by t h e c h a r a c t e r o f e m u ls io n s p r e p a r e d w i th m agnesium and f e r r i c a r a b a t e s and o t h e r r e l a t e d compounds. T h ro u g h o u t t h i s i n v e s t i g a t i o n w a te r was em ployed o f d e f i n i t e h y d ro g e n i o n c o n c e n t r a t i o n Pg 5*8 t o 6 * 4 . H av ing e s t a b l i s h e d t h e c h a r a c t e r o f e m u ls io n s p ro d u c e d when th e s a l t s o f compounds o f t h e n a t u r e o f a r a b i c a c i d a r e em ployed a s e m u l s i f y i n g a g e n t s , t h e n e x t s e r i e s o f i n v e s t i g a t i o n s was d i r e c t e d to d e te rm in e t h e i n f l u e n c e o f c h an g e s o f h y d ro g e n i o n c o n c e n t r a t i o n upon th e o i l - i n - w a t e r e m u ls io n s when a c a c i a and t r a g a c a n t h w ere employed a s e m u l s i f y i n g a g e n t s . M ethod o f S tu d y o f th e I n f l u e n c e o f Hydrogen i o n Concen­ t r a t i o n upon O i l - i n - W a t e r E m u ls io n s . A c a c ia and t r a g a c a n t h w ere th e two e m u l s i f y i n g a g e n t s s t u d i e d w i th e m u ls io n s o f c o t t o n s e e d and m in e r a l o i l s ( H u j o l ) . S o l u t i o n o f v a r i o u s h y d ro g en i o n c o n c e n t r a t i o n s w ere p r e p a r e d b y m ix in g s t a n d a r d sodium h y d ro x id e s o l u t i o n and s t a n d a r d h y d r o c h l o r i c a c id r e s p e c t i v e l y , w i th w a te r i n v a r i o u s d i l u t i o n s . The p £ o f t h e s e s o l u t i o n s was d e te r m in e d by th e e l e c t r o m e t r i c m e th o d . T hese s o l u t i o n s s e rv e d a s th e d i l u e n t s i n t h e p r e p a r a t i o n o f 25 p e r c e n t e m u ls io n s o f th e o i l - t h e t o t a l volum e o f t h e e m u ls io n i n each c a se was 40 c c . - 20 I n t h e e m u ls io n s made w i th t r a g a c a n t h 0*5 Gm* o f t h e t r a g a c a n t h was em ployed , w h e re a s 2 .5 Gm. o f a c a c i a Yiras u se d i n th e e m u ls io n s p r e p a r e d w i th t h i s s u b s t a n c e . The e m u ls io n s w ere p r e p a r e d by t r i t u r a t i o n i n a m o r ta r - m ix in g th e e m u l s i f y i n g a g e n t w i th th e o i l and a d d in g t h e a q u eo u s s o l u ­ t i o n s - a s f a r a s p o s s i b l e u n i f o r m c o n d i t i o n s o f t e m p e r a t u r e , p r e s s u r e and t im e o f t r i t u r a t i o n and r a p i d i t y o f d i l u t i o n w ere k e p t c o n s t a n t * The f i n i s h e d e m u ls io n s w ere s t o r e d a t room t e m p e r a tu r e i n s m a l l g r a d u a t e d c y l i n d e r s and t h e i r perm anence s t u d i e d . Com plete s e p a r a t i o n o f th e e m u l s i f i e d p o r t i o n from th e a q u eo u s l a y e r i s te rm e d s e p a r a t i o n , c re am in g o r p a r t i a l s e p a r a t i o n , w h ic h i s e a s i l y r e —i n c o r p o r a t e d by s im p le a g i t a t i o n i s n o t r e g a r d e d a s s e p a r a t i o n . - 2 1 - O b s e r v a t i o n s u p on t h e Changes o f P jj i n O i l - i n - W a t e r E m u ls io n s . T a b le X I. C o t to n s e e d O i l E m u l s i f i e d w i t h Ao.sc.is. D eg ree o f S e p a r a t i o n i n e e . i n d i f f e r e n t __________________________Time P e r i o d s . _______ Ho. .. 1 .5 H o u rs 7 Days 14 Days 22 Days 30 Days 37 Days 50 Days 1 0*4 14 C .S . C.S* C .S . C .S . C .S . 2 0 .9 5 10 10 10 10 10 3 1 . 4 2 5 5 5 5 5 4 2 .0 5 2 .9 4 5 3 .8 5 7 4 .4 5 8 5 .1 9 0 .3 10 6 .9 11 7 .8 5 12 8 . 7 1 13 1 0 .5 3 14 1 1 .8 C .S . C .S . C.S* • C .S . . C .S . C .S . 15 1 2 .5 C .S . C.S* C .S . C .S . C .S . C .S . 16 1 3 .2 C .S . C .S . C .S . C .S . C .S . C .S . C .S . C .S . ~ C om plete S e p a r a t i o n . A f t e r t h i s p e r i o d t h e r e was no change n o t i c e d f o r weeks and t h e e m u ls io n s when d i s c a r d e d m onths l a t e r r e t a i n e d th e r e l a t i o n ­ s h i p t o perm anence, a s i n d i c a t e d by t h e t a b l e * The c re a m in g e f f e c t r e a c h e d a maximum o f 27 c c . i n a b o u t 22 d a y s . However, a s m e n t io n ­ ed b e f o r e t h i s phenomenon was n o t c o n s i d e r e d a s s e p a r a t i o n . A n o th e r s e r i e s o f c o t t o n s e e d o i l e m u ls io n s w i th a c a c i a was p r e p a r e d o v e r a p p r o x i m a t e ly t h e same h u t s o l u ui ons o f s l i g h t l y d i f f e r e n t v a l u e s w ere em ployed . T a b le I I I . C o t to n s e e d O i l E m u ls i f i e d w i t h A c a c ia . D eg ree o f S e p a r a t i o n i n c c . i n D i f f e r e n t Time P e r i o d s . h o . pH 1 .5 12 D j1 Y 2T3 Hr* H r* ' 2 3 6 9 14 21 29 37 45 63 l 0 . 6 1 1 .5 2 3 3 3 5 6 C .S , C .S . C .S , 2 1 .0 5 0*5 1 1 1 1 1 2 4 4 4 4 3 1 .6 0*5 0 .5 0*5 0*5 0 .5 0*5 0 .5 0*5 0 .5 0 .5 4 2*65 5 3 . 4 6 4*2 7 5 .2 8 6*25 9 7 .8 10 8 . 5 11 9*45 12 1 0 .3 5 13 11*8 1 L 1 , 2 2 2 5 6 6 7 7 14 1 2 .4 3 cc* y e l ­ low deep y e l ­ low deep y e l ­ low 3 deep y e l ­ low 3 5 5 7 15 C .S . C.S. C.S. 15 13*35 C.S* C.S* C .S . c * s . C .S . C.S,.C.S* C.S* C .S . C .S . C.S. C.S* L ik e w is e i n t h i s s e r i e s th e c re am in g e f f e c t r e a c h e d a maximum o f 27 co* i n a b o u t 22 days* - 23 F ig* I I . C o t to n s e e d O i l E m u ls io n s w i th A c a c ia f r c m T a b le I l l a f t e r 37 d a y s . From l e f t t o r i g h t 1 -1 5 . t F i g . I I I . C o t to n s e e d O i l E m u ls io n s w i t h A c a c ia from T ab le I l l s h o w i n g # 1 , #6 and #15 a f t e r 37 d a y s . TABLE I V . C o t to n s e e d O i l E m u l s i f i e d w i t h T ra g a c a n th c c , i n D i f f e r e n t Time P e r i o d s Na* pH 12 D A "5r s Hr s . 7 14 22 30 37 50 74 1 0 . 4 3 5 5 5 5 5 C.S* 2 0*9 0 .5 1 2 2 2 2 C .S . 3 1 . 4 0 .5 1 1 1 1 1 1 4 2 .0 3 6 9 10 13 13 C .S . 5 2 .9 4 9 17 19 26 27 C .S . C .S . 6 3 .8 5 1 2 2 2 2 5 C .S . 7 4 .4 5 9 18 26 28 29 C .S . C .S . 8 5 . 1 2 3 4. 6 8 C .S . C .S . 9 6 .3 1 10 6 .9 25 28 29 C .S . C .S . 11 7 .8 5 6 10 22 24 26 26 C .S . 12 8 . 7 3 5 9 11 14 C .S . C .S . 13 1 0 .5 - 2 4 6 8 10 C.S* C .S . 14 1 1 .8 y e l ­ low C .S . C .S . C .S . C .S . C .S . C .S . 15 1 2 .5 y e l ­ low C .S . C .S . C .S . C .S . C .S . C .S . C .S . 16 1 3 .2 C .S . C .S . C .S . C .S . C .S . C .S . C .S . C .S . - 2 5 - - TABLE Y - C o t to n s e e d O i l E m u ls i f ie d - w i th T r a g a c a n th ________ D egree o f S e p a r a t i o n i n c c , i n D i f f e r e n t Time P e r io d s * K o* pH 12 Hr s . D A Y S 2 5 10 17 25 33 41 58 100 130 1 0*6 2 3 4 5 8 10 j2 1*05 1 1*5 2 6 10 3 1*6 1 8 20 4 2*65 5 16 25 5 3*4 2 5 11 17 C .S . 6 4*2 2 3 6 8 11 12 C .S . 7 5 .2 2 5 10 15 23 C .S . 8 6*25 1 5 8 11 17 C.S* 9 7*8 1 5 22 30 30 35 35 C.S* 10 8 . 5 2 4 10 11 16 22 o . s . 11 9*45 3 8 10 16 21 C .S . 12 10*35 7 21 25 26 26 26 C .S . 13 11*8 25 25 25 25 27 27 27 C .S . 14 12*4 l i g h t y e l lo w d e e p e r y e l lo w d e e p e r y e l lo w 3 G .S . C.S* C.S* C.S* C .S . C.S* C .S . 15 13*35 deep y e l lo w 0*3* 0 ,3* C.S* C.S* C.S* C.S* C.S* C .S . C.S* C .S . rfig;# IV . C o t to n s e e d O i l Em ulsi ons w i th T T a g a c a n th a f t e r 41 d a y s f ro m T a b le V#, From l e f t to r i g h t 1 -15 'r F ig # -V. C o t to n s e e d O i l E m u ls io n e w ith T r a g a c a n th §Z and # 1 4 a f t e r 41 d a y s . * 27 T ab le VI - M in e r a l O i l E m u l s i f i e d w i th A c a c ia No* pH 3 V'JU ^ J . U J JL . L JUL D A Y S Hr s . 1 2 4 7 12 19 27 35 43 60 100 1 0*6 1 2 2 2 3 20 26 27 27 27 2 1 .0 5 1 1 1 2 3 3 3 3 3 3 1 .6 4 2*65 5 3 .4 6 4 .2 7 5 .2 8 6 .2 5 9 7 .8 10 8 . 5 11 9 .4 5 12 1 0 .3 5 13 1 1 .8 y e l lo w d e e p e r y e l lo w d eep y e l ­ low d eep y e l ­ low 14 1 2 .4 1 1 2 25 25 25 26 26 26 26 26 15 1 3 .3 5 y e l lo w 1 .5 d e e p e r y e l lo w 2 C .S . C .S . C .S . C .S . C .S . C .S . C .S . C .S . C .S . C .S . F ig * VI M in e r a l Q i l E m u ls io n s w i th A c a c ia from, t a b l e V T a f te r 35 d a y s . Front l e f t t o r i g h t No* 1 t o 15 , --------» --------------- *—i F ig * V II M i n e r a l , . G i l E m u ls io n s w i t h A c a c ia from t a b l e VT- # 1 , #7 and #15 a f t e r 35 days* - 29 - T a b le V II - M in e r a l O i l E m u l s i f i e d w i th T r a g a c a n th D egree o f S e p a r a t i o n i n cc* I n D i f f e r e n t Time P e r i o d s . IT o . pH 12 Hr s . DAYS 1 3 6 11 17 25 33 41 60 100 1 0*6 2 4 8 12 18 21 22 22 2 1*05 0*5 5 10 17 21 22 23 24 27 3 1*6 2 2 9 22 4 2*65 1 3 ' 5 8 12 19 25 5 3*4 2 7 12 17 21 22 26 28 6 4* 2 2 3 6 10 10 20 26 7 5*2 4 8 11 15 16 17 21 26 8 6*25 1 5 10 18 23 26 28 29 9 7*8 3 6 10 16 21 23 25 28 10 8*5 2 8 11 18 20 21 23 24 11 9*45 10 24 28 30 30 31 38 12 10*35 7 10 16 20 22 25 38 13 11*8 25 25 30 30 30 30 30 30 14 12*4 ye H ow d e e p e r y e l lo w 1 d e e p e r y e l lo w 2 C.S* C.S* C .S . C.S* C .S . C .S . C.S* c u s . 15 1 3 .3 5 deep y e l lo w 2 10 20 C .S . C .S . C .S . C .S . C .S * C.S.- C .S . 0 . 3 . T"-»!" 1 ' V. ■ F i g . V I I I M i n e r a l o i l E m u ls io n s w ith: T ra g a c a n th f ro m T a b le V T i a f t e r 33 days* L e f t t o r i g h t 1 -1 5 . FIG . IX M in e r a l O i l E m u ls io n s w i th T ra g a c a n th f ro m T a b le Y H #3 and #15 . - 51 - T a b l e s H to VU i n c l u s i v e i n d i c a t e t h a t t h e r e i s a lo n g r a n g e o f h y d ro g e n i o n c o n c e n t r a t i o n o v e r which th e e m u ls io n s made w ith a c a c i a a r e s t a b l e and f u r t h e r t h a t t h e s e r e s u l t s a r e th e same w i t h a v e g e t a b l e o r a m in e r a l o i l * W ith t r a g a c a n t h t h e m ost s t a b l e p o i n t o f h y d ro g e n i o n c o n c e n t r a t i o n i s f ro m 1*8 to 2*3 . The a v e r a g e s t a b i l i t y o f th e e x p e r im e n t s r e c o r d e d i n t a b l e s I I to VTI c a n be e a s i l y o b s e rv e d from g r a p h s I and I I . The o r d i n a t e s o f g ra p h I I r e p r e s e n t th e amount o f s e p a r a t i o n p e r d a y o v e r a p e r i o d o f 60 d a y s and m u l t i p l i e d by t e n to e l i m i n a t e d e c im a ls * Graph I I i n d i c a t e s t h a t o v e r a l a r g e ra n g e o f t h e s t a b l e p o i n t i s a p p r o x i m a t e ly ? g 1 * 9 0 . W ith t h i s i n m ind o t h e r s e r i e s o f e m u ls io n s w ere p r e p a r e d c o v e r in g t h e a c i d ra n g e o f PH w i th s m a l l e r v a r i a t i o n s i n o r d e r to d e te r m in e th e e x a c t s t a b l e p o i n t . These r e s u l t s w i t h t r a g a c a n t h a r e r e c o r d e d i n T a b le s V I H t o X IIa n d th e a v e r a g e s t a b i l i t y o v e r a p e r i o d o f 20 d a y s i s p l o t t e d i n g ra p h I I I * *“ 3 3 GRAPH HO* 1 - STABILITY OP EMULSIONS WITH ACACIA AND THEIR HYDROGEN ION CONCENTRATIONS Days' UNALTERED STABILITY 40 30 1C rrno o - 33 - GRAPH NO. 2 - STABILITY OF EMULSIONS WITH TRAGACANTH AND THEIR HYDROGEN ION CONCENTRATIONS cc* [Per Day 10 12 14 - 34 - T a b le T i l l C o t to n s e e d O i l E m u l s i f i e d with. T rag acan th . D eg ree o f S e p a r a t i o n i n cc* i n D i f f e r e n t Time P e r i o d s , To* PH • D j L X X \s ^ ft U S J . XX X / X J 4 6 8 10 12 14 17 21 25 32 38 1 1 1*5 1 .5 1*5 2 2 2 3 4 5 6*5 8 2 1*92 1 2 3 .5 5 8 11 3 2 .0 8 0 .5 1 2*5 4 4 2 .2 2 1 3 8 13 5 2 . 4 0 .5 1 2 3 6 2 .6 5 1 2 5 11 14 7 2 .9 4 1 1 2 2 .5 4 4 5 9 12 8 3 .0 2 0 .5 0*5 1 1 2 3 3 5 9 3*15 1*5 3 4 6. 7 9 11 13 16 18 10 3*3 1 1*5 2 3 4 6 8 10 11 3*6 2 4 7 9 11 13 17 19 22 23 12 3 .7 2*5 4 7 9 11 13 17 19 22 24 13 3*82 3 5 9 12 15 17 20 21 22 23 14 4 3 7 13 17 19 22 23 24 24 25 15 4*1 2 5 9 13 17 19 22 25 26 26 27 16 4* 4 1 5 10 15 17 19 21 23 24 25 26 17 4*5 2 8 21 27 28 28 28 29 29 29 29 35 T a b le IX C o t to n s e e d O i l E m u l s i f i e d w i th T r a g a c a n th D egree o f S e p a r a t i o n i n cc-. i n D i f f e r e n t Time P e r i o d s . No* PH D A Y S 4 6 8 10 12 14 17 21 25 32 " 38 1 1 1 1 2 3 3 3 4 5 6 9 11 2 1 .9 2 0 .5 0 .5 0 .5 1 1 .5 3 5 9 13 3 2 .0 8 0 .5 1 .5 2 4 2 .2 2 1 2 4 6 5 2 . 4 1 3 6 13 18 6 2 .6 5 0 .5 1 2 5 8 13 16 7 2 .9 4 0 .5 2 4 5 7 10 15 18 23 ' 24 8 3 .0 2 0 .5 1 1 1 2 3 4 6 7 9 3 .1 5 1 1 2 3 4 6 7 . 10 3 .3 1 2 2 .5 3 4 6 8 11 14 11 5 .6 2 5 9 10 12 15 16 20 23 24 12 3 .7 1 3 5 8 10 14 19 22 23 24 13 3 .8 2 2 4 7 9 10 13 17 19 22 23 14 4 .0 1*5 5 8 10 12 13 15 18 20 22 23 15 4 . 1 1 3 5 6 8 10 11 14 17 19 21 16 4 . 4 2 5 9 11 13 15 17 19 23 25 25 17 4 . 5 2 5 8 12 15 17 21 24 25 25 26 - 36 - T a b le X, M in e r a l O i l E m u l s i f i e d w i th T r a g a c a n th D egree o f S e p a r a t i o n i n cc* i n D i f f e r e n t Time P e r io d s * No. Jp D A Y S 3 5 7 9 11 13 16 20 24 31 37 1 1 1 2 5 9 12 14 1 4 19 20 22 23 2 1 .9 2 1 1 3 7 14 19 3 2 .0 8 1 .5 rr-o 5 10 20 20 27 27 4 2 .2 2 0 .5 0 .5 1 6 15 24 26 5 2 .4 1 .5 4 9 17 22 26 27 5 2 .6 5 1 2 .5 4 6 11 16 O.S. 0 . 3 . 7 2 .9 4 5 14 19 22 25 25 25 0 .3 . C . S . 8 3 .0 2 2 14 19 22 25 28 28 C .S . O .S . 9 3 .1 5 0 1 2 3 4 6 9 12 17 19 10 3 .3 2 6 14 19 23 23 27 27 r \ e*O % a*. C .S . 11 3 .5 r ro 11 22 25 26 27 27 2.7 0 . 3 . C . S . 12 3 .7 1 8 18 22 24 25 25 OfjO 27 0*3 . C .S . 13 3 .8 2 9 13 23 25 26 27 28 28 C .S . C .S . 14 4 .0 2 17 21 24 2 4 26 27 27 27 C. S . r% nO • o * 15 4 . 1 13 23 25 26 26 27 28 28 O .S . 0 . 3 . 13 4 .4 4 12 22 26 27 29 29 29 C .S . C. S . 17 4 .5 10 21 25 26 27 28 28 28 C. S . C. S . - 37 - T a b le XI M in e ra l O il E m u ls i f i ed with Tragacanth Degree o f S e p a ra t io n In cc . i n D i f f e r e n t Time P e r io d s 10 12 2114 17 25 15 1818 21 23 23 O.S 0 .5 13 18 C.S,. 12 17 23 10 16 24 C.S 14 21 25 C.S 2 .6 5 22 28 30 16 22 25 C.S. 14 16 10 15 17 C.S 10 21 25 27 28 28 28 C.S. 11 15 21 23 25 26 27 27 C.S 12 10 14 21 21 22 22 23 24 C.S 13 12 12 21 22 22 24 25 25 14 1712 21 23 24 24 25 15 2215 28 28 29 29 29 29 C.S 16 14 13 23 25 26 27 28 30 C.S 1417 4 .5 20 25 26 27 28 28 C.S - 38 - TABLE X II M in e ra l O i l E m u ls i f ie d , w i th T ra g a c a n th D egree o f S e p a r a t i o n i n c c , i n D i f f e r e n t Time P e r i o d s . No* PH D A Y S 5 8 10 12 14 20 24 30 37 1 1 3*5 8 11 13 16 19 20 22 23 2 1*92 1 2 4 . 5 7 9 9 17 20 22 3 2*08 0 .5 1 2 5 12 20 23 4 2*22 2 6 10 16 17 5 2*4 1 2 5 9 12 6 2*65 1 4 8 15 20 25 27 7 2 .9 4 1 2 3 6 8 8 3*02 1 2 3 6 8 12 15 9 3*15 3 3 4 5 9 9 19 23 10 3*3 5 9 9 16 19 22 25 26 C.S* 11 3*6 14 20 23 25 25 27 27 27 C .S . 12 3 .7 15 20 24 26 27 27 C .S . C .S . C .S . 13 3*82 7 15 22 28 28 28 28 23 C .S . 14 4 9 15 18 22 24 25 25 25 C .S . 15 4*1 9 15 20 24 24 25 25 25 C .S . 15 4 . 4 9 15 18 20 22 23 24 25 C .S . 17 4 .5 10 17 19 21 22 23 24 25 C .S . - 39 - GRAPH HO* 3 - STABILITY* OH EMULSIONS WITH TRAGACANTH c c . p e r day AND THEIR HYDROGEN ION CONCENTRATIONS 12 10 The c c . o f s e p a r a t i o n p e r day was m u l t i p l i e d by t e n to c o n s t r u c t th e o r d i n a t e s o f t h i s g r a p h . - 4 0 - Three s e r i e s of a c a c i a emulsions were p rep a red over the same range of hydrogen io n c o n c e n t r a t i o n , bu t l i t t l e or no v a r i a t i o n i n t h e i r s t a b i l i t y was obse rved . Those p rep ared w i th a 1 seemed to s e p a ra te a creamy l a y e r more r e a d i l y and u l t i m a t e l y ( a f t e r about 20 days) s e p a ra te to the e x t e n t o f 5 t o 10 cc . The e f f e c t o f sodium c h lo r id e s o l u t i o n in v a r io u s c o n c e n t r a t i o n s upon these emulsions was s tu d ie d i n o rde r to de te rm ine the i n f lu e n c e o f the sodium io n . When s tu d ied i n c o n c e n t r a t i o n s from 1 IT. to 10"6W; i t was found t h a t none of th e s e c o n c e n t r a t i o n s o f sodium c h lo r id e s o l u t i o n a f f e c t e d the s t a b i l i t y of the em uls ion . Within 4- o r 5 days a l l emulsions p re p a re d 7dth ac a c ia sep a ra te d a creamy l a y e r o f 25-27 cc . and remained i n t h a t c o n d i t io n f o r more th an 150 days , the e f f e c t o f a l l c o n c e n t r a t io n s of sodium c h lo r id e used showing th e same r e s u l t s , as shown by f ig u r e X. F ig . X Mineral Oil Emulsions with Acacia and Sodium Chloride Cone* of ITaCL l e f t to r i g h t ITT. to 10-%. - 41 - The i n f lu e n c e of sodium c h lo r id e s o l u t i o n s upon t r a g a ­ c a n th emulsions of M ineral O i l i s shown by the fo l lo w in g t a b l e : Table X II I M inera l O il E m u ls i f ied with Tragacanth in Various C o n c en t ra t io n s of Sodium Chloride S o lu t io n . Degree o f S e p a ra t io n i n cc . i n D i f f e r e n t Time P e r io d s . Ho. F o r ­ m a l i t y D A Y S 5 11 19 27 25 53 100 1 1 3 5 8 10 15 2 0 .1 1 2 5 8 10 r-ro i o ~ 2 1 1 2 4 8 4 10_a 1 5 9 15 20 27 5 10"4 1 3 5 8 15 27 6 H O 1 C JI 10 10 15 17 23 27 7 10 ~3 10 15 21 23 25 27 27 F ig . XI M ineral Oil Emulsions with Tragacanth from Table X I I I a f t e r 27 days. F ig . X II M inera l Gil Emulsions w ith Tragacanth and Sodium C h lo r id e , §7 and $3 a f t e r 2 7 days* I n o rd e r to s tudy the i n f lu e n c e of the hydrogen ion produced from an o th e r sou rce , s o lu t io n s of s u lp h u r ic a c id were p re p a re d and the same type of emulsions were made from t h e s e . 7 i t h a c a c ia l i t t l e change was n o t ic e d except i n the emulsion of a P 1*2 where p a r t i a l s e p a r a t i o n occu rred . The r e s u l t s ob ta in ed with t r a g a c a n t h may be 'Observed from'; te~bl.®s 14 and 15 and Graph IV. - 43 - T a b le XIV M i n e r a l O i l E m u l s i f i e d w i th T r a g a c a n th i n t h e P r e s e n c e o f S u lp h u r i c Acid* ITo. PH V I A J . A A O U U a . J U I U V ^ X V - /X X k P • D A Y S 4 7 1 1 15 20 26 1 1 * 2 2 8 15 16 19 2 0 2 2 .0 5 1 3 3 2 .8 3 2 3 5 7 4 4 . 1 3 1 0 16 19 2 2 24 5 4 .4 3 5 14 2 £ 23 24 25 6 4 .9 4 3 19 25 26 26 27 T ab le XV C o t to n s e e d O i l E m u l s i f i e d w i th T r a g a c a n th i n th e P r e s e n c e o f S u lp h u r i c Acid* ITo. PH D A Y S 6 1 0 14 19 27 1 1 . 2 1 2 2 4 2 2 .0 5 3 2 .8 3 1 2 6 4 4 . 1 2 3 S 5 4 .4 5 1 6. 1 0 12 1 2 6 4 .9 4 3 5 9 1 0 - 44 GRAPH HO. 4 - STABILITY OR EMULSIONS WITH TRAGACANTH cc* P e r AND THEIR HYDROGEN ION CONCENTRATIONS d ay s u l p h u r i c a c i d u s e d - 45 - S tu d y o f t h e P h y s i c a l P r o p e r t i e s o f th e E m u ls io n s . S u r f a c e T en s io n # T h is p r o p e r t y was d e te r m in e d a t 35° C* w i th a s t a n d a r d i z e d Du Fouy t e n s i o m e t e r . The r e s u l t s w i th t r a g a c a n t h c an be s e e n i n (£raph V and w i t h a c a c i a i n T ab le 16* T ab le XVI S u r f a c e T e n s io n o f E m u ls io n s w i t h A c a c ia a t 35° C* ¥o* PH Dynes p e r Cm. 1 0*4 54*8 2 1 5 7 .3 3 2*08 6 2 .2 4. 3 .0 2 63 5 4 64*8 6 5 .6 6 6 . 1 7 7 .3 6 6 * 6 8 7 .7 5 6 6 * 2 9 9 .2 6 5 .9 1 0 9*95 64*1 1 1 11*75 6 2 .3 1 2 1 2 .2 5 6 8 . 1 13 1 3 .2 5 59.4- - 46 - GRAPH NO. 5 - SURFACE TENSION OF EMULSIONS WITH TRAGACANTH and THEIR HYDROGEN ION CONCENTRATIONS. Dynes p e r Cm. 52 50 48 46 44 0 2 P.II * 47 - I n t e r f a c i a l t e n s i o n . The i n t e r f a c i a l t e n s i o n was m easu red a t 27° C. by a p i p e t t e s i m i l a r to th e one u se d by Donnan (17) and h i s s t u d e n t s ( s e e f i g u r e X I I I ) . The i n t e r f a c i a l t e n s i o n o f w a te r was t a k e n a s 1 0 and t h e f o l lo w in g F i g . X I I I f o rm u la em p lo yed , where T i s t h e i n t e r f a c i a l t e n s i o n , Y th e volume o f o i l and N t h e number o f d rop s* Toe I f o r p u r e w a te r and th e n YT = K I H 10 = 3K K « 80 A Y T = 80 _ 11 * 48 - The r e s u l t s o f t h e s e m e a su re m e n ts a r e p l o t t e d i n G raph V I . V i s c o s i t y . U s in g d i s t i l l e d w a te r a s a s t a n d a r d a t 30° C* th e r e l a t i v e v i s c o s i t i e s o f a s e r i e s o f e m u ls io n s were d e te r m in e d by m e a s u r in g t h e t im e i n se c o n d s r e q u i r e d f o r a d e f i n i t e volume o f th e e m u ls io n to r u n from a p i p e t t e w i t h a c a p i l l a r y t i p com pared w i t h t h e t im e r e q u i r e d f o r t h e f lo w o f th e same volum e o f w a t e r . T hrough t h e e n t i r e r a n g e o f h y d ro g e n i o n c o n c e n t r a t i o n th e r e l a t i v e v i s c o s i t y o f th e a c a c i a e m u ls io n s was 1 .2 5 . The v i s c o s i t i e s o f th e t r a g a c a n t h e m u ls io n s may be se e n i n Graph V I I . 49 GRAPH HO. 6 - INTERFACIAL TEWS I OH OF MINERAL OIL AND SOLUTIONS OF VARIOUS HYDROGEN ION CONCENTRATIONS R e la t Lve I n t e r f a c i a l T e n s io n 10 10 IS 50 GRAPH NO. 7 - EMULSIONS YifllH TRAGACANTH, THEIR RELATIVE VISCOSITIES AND THEIR HYDROGEN ION CONCENTRATIONS. T---- IQ IS 14 _ R1 _ S iz e o f P a r t i c l e * E m u ls io n s o f M in e r a l O i l w ere p r e p a r e d a f t e r c o l o r i n g t h e o i l w i th a l l c a n e t r o o t and th e s i z e o f th e p a r t i c l e s m e a su re d m i c r o s c o p i c a l l y * The r e s u l t s a re t a b u l a t e d i n T a b le s XVII and X V III* T ab le XVII M in e ra l O i l E m u l s i f i e d w i th A c a c ia . Mo. PH Average. D ia m e te r o f P a r t i c l e s iLn M icrons 1 0*4 3 8 1 0 1 2 15 18 2 7 .3 3 6 9 13 13 13 3 7*75 4 5 1 0 1 2 1 2 1 2 4 13 .25 4 7 13 15 15 15 T a b le X V III Mo. PH A verage D ia m e te r o f P a r t i c l e s i n M icrons 1 0*4 17 2 0 25 30 2 1 17 2 0 25 25 3 5*6 1 0 17 20 20 4 13*25 40 50 1 0 0 1 1 0 G e ls o f t r a g a c a n t h i n w a te r o f d i f f e r e n t h y d ro g e n i o n c o n c e n t r a t i o n s w ere p r e p a r e d and a f t e r s t a n d in g f o r 3 d ay s f i g u r e XIV shows, t h e s e p a r a t i o n o f w a te r a t th e s u r f a c e . The g e l s w ere p r e p a r e d by r u b b in g 0 .5 Gm* o f t r a g a c a n t h w ith 25 c c . o f w a te r u n t i l g e l a t i n i z a t i o n o c c u r re d F i g u r e XIY. T r a g a c a n th G e l s . Lower f i g u r e s i n d i c a t e P o f G e l .ii - 53 - Method o f S tu d y o f th e I n f lu e n c e , o f Changes o f H ydrogen I o n C o n c e n t r a t i o n upon Em ulsl ons o f t h e U a t e r - i n - O i l Type* The e m u ls io n s w ere p r e p a r e d i n q u a n t i t i e s o f 40 c c . e a c h , o n u l s i f y i n g i n e ac h c a s e 1 0 c c . o f t h e aq u eo u s m a t e r i a l , p r o d u c in g a 25 p e r c e n t by volume w a t e r - i n - o i l e m u ls io n . P r e l i m i n a r y e x p e r i m e n t a t i o n w i t h m agnesium o l e a t e a s an e m u l s i f y i n g a g e n t showed t h a t one gram o f th e com­ pound was s u f f i c i e n t t o a n u l s i f y th e d e s i g n a t e d q u a n t i t y o f w a t e r . I t was f u r t h e r o b s e rv e d t h a t th e age o f t h e m agnesium o l e a t e i n f l u e n c e d i t s e m u l s i f y i n g c a p a c i t y . 'Upon k e e p in g , ev en i n t i g h t l y s t o p p e r e d c o n t a i n e r s th e compound t e n d s to h a r d e n and became b r i t t l e , i n t h i s co n ­ d i t i o n i t d o e s n o t m ix r e a d i l y w i th t h e o i l and th e em ul­ s i o n s fo rm ed b y u s i n g t h i s s u b s ta n c e a r e g r a n d u l a r and u n s t a b l e . The r e l a t i v e d e g r e e s of s t a b i l i t y o f t h e a n u l s i o n s made w i t h f r e s h l y p r e c i p i t a t e d m agnesium o l e a t e , and th o s e made w i th the p r o d u c t w hich h a d been k e p t f o r s i x o r e i g h t weeks c a n be o b s e r v e d by s t u d y i n g th e f o l l o w ­ in g t a b l e s o f s t a b i l i t y . The aq ueous s o l u t i o n s o f v a r i o u s h y d ro g e n i o n c o n c e n t r a t i o n s w ere p r e p a r e d a s i n th e f o r e g o i n g e x p e r i ­ m en ts b y th e a d d i t i o n s o f v a r i o u s q u a n t i t i e s o f h y d r o ­ c h l o r i c a c id and sod ium h y d r o x id e to d i s t i l l e d w a t e r . The o f t h e s e s o l u t i o n s was d e te rm in e d e l e c t r o m e t r i c a l l y . As t h e s e u n b u f f e r e d m i x t u r e s , n e a r t h e n e u t r a l p o i n t , change i n h y d ro g e n i o n c o n c e n t r a t i o n q u i t e q u i c k l y , th e e m u ls io n s o f t h e m ix t u r e s n e a r P^- 7 w ere p r e p a r e d a s soon as. p o s s i b l e a f t e r th e h y d ro g en i o n c o n c e n t r a t i o n m e a s u r e ­ m ent* The e m u l s i f i c a t i o n was a c c o m p l i s h e d by t r i t u r a t i n g t h e e m u l s i f y i n g a g e n t w i t h 18 cc* o f o i l a t 25° C, and a d d in g , i n one p o r t i o n th e . 1 0 c c . o f a q u eo u s f l u i d . A f t e r b r i s k t r i t u r a t i o n t h e f o r m a t io n o f th e e m u ls io n n u c le u s c o u ld be e a s i l y a s c e r t a i n e d by th e sudd en i n c r e a s e i n v i s c o u s n e s s and th e o c c u r r e n c e o f a c r a c k l i n g sound when t h e p e s t l e was p u l l e d t h r o u g h t h e e m u ls io n . With c o n t i n u e d t r i t u r a t i o n th e e m u ls io n n u c l e u s was d i l u t e d to t h e p r o p e r volume and s t o r e d i n d r y , w e l l - s t o p p e r e d g r a d u a t e d c o n t a i n e r s * The s e p a r a t i o n o f i n v e r t e d e m u ls io n m ust n o t be m i s t a k e n f o r th e g r a d u a l s e t t l i n g o f . t h e h e a v i e r e m u l s i f i e d w a te r t o t h e b o t to m o f t h e c o n t a i n e r , f o r t h i s m ig h t e a s i l y be i n c o r p o r a t e d by a g i t a t i o n . When a c t u a l s e p a r a ­ t i o n o c c u r s t h e r e a p p e a r s a c l e a r aqueous f l u i d a t t h e b o t ­ tom o f t h e e m u ls io n w hich c a n n o t be r e i n c o r p o r a t e d by a g i t a t i o n . 7fith c e r t a i n e m u ls io n s o f t h i s t y p e , em ploy­ i n g f r e s h l y p r e c i p i t a t e d m agnesium o l e a t e . 7 t h e a u t h o r h a s o b s e r v e d no s e p a r a t i o n i n a p e r i o d of e i g h t or t e n m o n th s . Whe^L, h o w e v e r , e m u ls io n s a r e p r e p a r e d w i t h o l d e r sam p le s o f th e e m u l s i f y i n g a g e n t , t h e s e p a r a t i o n b e g in s i n a much s h o r t e r p e r i o d o f t i m e . - 55 O b s e r v a t i o n s upon th e C hanges o f i n W a te r—i n - O i l E m u l s io n s . TABLE XIX E m u ls io n s o f S o l u t i o n s o f V a r io u s H ydrogen I o n C o n c e n t r a t i o n s i n M in e r a l O il* D egree o f S e p a r a t i o n i n D i f f e r e n t Time P e r i o d s . Ho. % 1 / 2 1 4 D A Y Sh r . h r . h r s . 1 3 4 7 1 1 15 2 0 28 38 |45 52 ' 59 6 6 73 80 87 94 1 0 .9 1 0 C.S 2 1 .3 6 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 3 1 .8 7 5 6 7 8 8 8 8 a a 8 8 8 8 a 8 8 8 8 4 3 .0 5 2 2 3 5 5 5 5. 5 5 5 5 5 5 5 5 5 5 3 .9 7 2 3 4 4 4 4 4 5 5 5 5 5 5 5 5 5 6- 4 .8 5 1 2 2 2 2 3. 4 4 4 4 4 4 5 5 5 7 5 .5 5 1 2 3 3 3 3 3 3 3 3 3 3 3 4 8 7 .5 5 1 2 2 2 3 3 3 3 3 3 3 4 4 4 9 8.02 2 2 3 4 4 4 4 5 5 5 5 5 5 5 5 5 10 9.25 2 2 3 3 4 4 5 5 5 5 5 5 5 5 5 5 11 1 0 .9 7 3 3 4 5 5 5 5 5 5 5 5 5 5 5 5 5 12 11.75 1 1 1 1 2 2 2 2 2 2 3 3 3 13 12.38 14 13.0 y e l ­ low G-rani u l a r C. 3. = Complete S e p a ra t io n - 56 - T ab le XX. E m u ls io n s o f S o l u t i o n s o f V a r io u s H yd rogen Io n C o n c e n t r a t io n s i n M in e r a l O i l . D eg ree o f S e p a r a t io n i n o o . i n d i f f e r e n t t im e p e r io d s . H o. ' P H i / ah r . 1 h r . 03 • D A T S 1 3 4| 7 11 15 20 28 38 4 5 52 59 66 73 80 87 9 4 1 0 .9 10 G .S 2 1 .3 5 8 10 10 CS 3 1 .8 7 3 5 5 5 6 5 6 5 e 5 6 5 5 6 6 6 7 7 4 3 .0 5 1 1 2 3 3 3 5 5 5 5 5 5 5 5 5 5 5 3 .9 7 4 4 5 5 5 5 5 5 5 5 5 6 6 6 6 6 6 4 .8 5 1 3 3 4 4 4 4 5 5 5 5 5 5 5 5 7 5 .5 5 1 1 2 2 3 3 3 3 4 4 4 4 4 4 4 4 8 7 .5 5 1 1 1 2 2 3 3 4 4 4 4 4 4 4 4 4 9 8 .0 2 2 2 2 3 3 4 4 4 5 5 5 5 5 5 5 5 10 9 .2 5 1 1 2 2 3 3 3 3 4 4 5 5 5 6 6 6 1 1 1 0 .9 7 2 2 3 3 4 4 4 4 4 4 4 5 5 5 5 5 12 1 1 .7 5 2 2 2 2 2 3 3 3 3 3 3 3 3 13 1 2 .3 8 1 4 1 3 .0 y e l ­ low G ran­ u l a r G . S . » C om p lete S e p a r a t io n 57m T a b le s number XIX and XX i n d i c a t e t h a t th e s t a b l e p o in t o f t h e s e e m u ls io n s i s n e a r th e p o in t 1 2 .3 8 * The m agnesium o l e a t e em p lo y ed i n t h e s e e m u ls io n s had b e e n p r e p a r e d a b o u t f o u r t e e n d a y s p r io r to i t s u s e . Graph number VTII show s t h e a v e r a g e s e p a r a t io n o f t h e s e two s e r i e s o f e m u ls io n s o v e r a p e r io d o f n in e t y - f o u r d a y s . - 58 - CC, P e r GRAPH NO* 8 - STABILITY OR EMULSIONS IN MINERAL OIL AND THEIR HYDROGEN ION CONCENTRATIONS 10 12 ‘4 6 'a '10 '12 '14 The o r d i n a t e s o f t h i s g ra p h r e p r e s e n t , t h e amount o f s e p a r a t i o n p e r day o v e r a p e r i o d o f n i n e t y - f o u r d a y s and m u l t i p l i e d by t e n t o e l i m i n a t e decim als* . P.H 59 - F igu re number .XV; shows the emulsions from t a b l e number X I X a f t e r t h i r t y days* Heading from l e f t to r i g h t th e se em uls ions a re numbered a s given i n t a b l e number XIX* F igure XV. Emulsions of S o lu t io n s of Various Hydrogen Ion C o n c en t ra t io n s i n Minera l Oil* 'J i th magnesium o l e a t e which was f r e s h l y p r e c i p i t a t e d , as observed with the fo rego ing ex p e r i i sn t s , the range of hydrogen io n c o n c e n t r a t io n a t 'which the emulsions a re un­ s t a b l e i s on the ac id s ide* with the f r e s h l y p r e c i p i t a t e d em uls i fy in g agent p r a c t i c a l l y the e n t i r e range of the PTJ sca le from P , . 1*87 to P 12.38 'were s t a b l e as shown byn li t a b l e number XXI* Yet on the a l k a l i n e s ide of the P„T s c a le m - P,T 10*97, 11.75 and 12.38 , the degree of creaming wasn l e s s than when the i n t e r n a l phase was c l o s e r to the n e u t r a l p o i n t . Table Xld shows th e s t a b i l i t y o f th e se emulsions over a p e r io d of e i g h t y —s i x days . 61 - T a b le N o. XXI Emulsions of S o lu t io n s o f Various Hydrogen Ion C o n c e n t r a t io n s i n I l i n e r a l O i l . ( f r e s h l y P r e c i p i t a t e d Magnesium O lea te) Mo 1 D A Y S h r . 3 7 12 20 30 37 44 51 58 65 72 79 8 6 1 0*9 8 8 9 9 9 9 9 9 9 9 9 9 9 9 2 1.36 1 1 1 1 1 1 1. 1 1 1 1 1 1 3 1.87 4 3.05 5 3.97 8 4.85 7 5.55 8 7.5 9 8.02 10 9.25 11 10.97 12 11.75 13 12.38 14 13.0 c o a r s 3 S O l i d raa s s — 62 — When o l i v e o i l was employed, as the e z t e r n a l phase, employ­ in g the sane magnesium o le a te t h a t was used i n the f i r s t s e r i e s o f em u ls io n s , the emulsions as a whole were more permanent. The d eg rees of s e p a r a t i o n of t h i s s e r i e s of emulsions a re g iven i n t a b l e s XXTTand XTTTT and the summary of th e s e r e s u l t s i s p l o t t e d i n Graph IX. 63 - T ab le XX II E m u ls io n s o f S o l u t i o n s o f V a r io u s H ydrogen I o n C o n c e n t r a t i o n s i n O liv e O i l . No. r>X 1 /2 ----- 1 D A Y S . XI h r . h r . 1 4 12 17 25 35 42 49 56 63 70 77 8 4 91 1 0 .9 10 c . s 2 1 .3 6 8 10 C. S 3 1 .8 7 1 2 2 2 2 2 2 2 2 2 2 2 2 2 4 3 .0 5 1 1 X 1 1 X 1 1 1 5 3 .9 7 1 1 1 1 1 1 1 1 S 4 .8 5 1 1 1 1 1 1 1 1 7 5 .5 5 1 1 1 1 1 1 1 1 8 7 .5 5 1 1 1 1 1 1 1 1 9 8 .0 2 1 1 1 1 1 1 1 1 10 9 .2 5 1 1 1 1 1 1 1 1 11 1 0 .9 7 12 1 1 .7 5 13 1 2 .3 8 14- 1 3 .0 y e l ­ low y e l ­ low 1 6 6 6 6 6 6 6 6 6 - 64 T a b le No* X X III Emulsions o f S o lu t io n s o f Various Hydrogen Ion C o n c e n t r a t io n s i n O live Gil* No PH 1 ■ 1 1/2 1 D A Y S hr* hr* 1 4 8 12 17 25 35 42 49 56 63 70 77 84 3L 1 0.9 10 C.S 2 1.36 8 10 C.S 3 1.87 1 1 1 2 2 2 2 2 2 2 2 2 2 2 4 3.05 1 1 1 1 1 1 1 1 1 5 3*97 1 1 1 1 1 1 1 1 6 4 .85 1 1 1 1 1 1 1 1 7 5 .55 1 1 1 1 1 1 1 1 8 7.55 1 1 1 1 1 1 1 1 9 CD « O 1 1 1 1 1 1 1 1 10 9.25 1 1 1 1 1 1 1 1 11 10.97 1C 11.75 13 12.38 14 13 .0 y e l ­ low y e l ­ low 6 S S 7 7 7 7 7 7 •e. 65 - STABILITY OF iMUISIONS IN OLIVE OIL A ® . THEIR HYDROGEN ION C ONCENTRATIONS. r * P 10 12 P - r 1410 12 T h e ^ o r d i n a t e s o f t h i s g r a p h r e p r e s e n t t h e amount o f s e p a r a t i o n p e r d a y o v e rThe r d i n a to p e r i o d o f n i n e t y - o n e d a y s and m u l t i p l i e d by t e n t o e l i m i n a t e f r a c t i o n s . f i g u r e number XVI shoves the emulsions made with o l iv e o i l a f t e r a p e r io d of t h i r t y days* Reading from l e f t to r i g h t the emulsions are numbered as given i n t a b l e number SSI I . F i g u r e XVT Fmulsions o f s o l u t i o n s of Various Hydrogen Ion C o n cen tra t io n s i n Olive O i l . The e f f e c t o f sodium c h lo r id e s o l u t i o n in v a r io u s c o n c e n t r a t i o n was s tu d ie d in o rder to determine the in f lu e n c e of the sodium io n . j ' i th s o l u t i o n s of sodium c h lo r id e in c o n c e n t r a t io n s 1H. to 10“ ^ N. i t was observed t h a t t h i s subs tance h a d p r a c t i c a l l y no in f lu e n c e upon the emulsions d i s p e r s e d in m inera l o i l . - 67 When o l i v e o i l was em ployed , i t was o b s e r v e d t h a t t h e e m u l s i o n s e x h i b i t e d a d e g r e e o f s t a b i l i t y which was i n v e r s e to th e c o n c e n t r a t i o n s o f sodium c h l o r i d e . The d e g r e e s o f s e p a r a t i o n w i th e a c h o f t h e s e s e r i e s o f e m u ls io n s i s shown i n t a b l e s XXIV and XXV. F i g u r e XVII shows t h e e m u l s i o n s i n m i n e r a l o i l a f t e r t h i r t y d a y s . R ead in g f rom l e f t t o r i g h t , t h e emul­ s i o n s a r e numbered a s g iv e n i n t a b l e XXIV* ~ 68 - T a b l e No* XXIV K m u is io n s o f S o l u t i o n o f Sodium C h l o r i d e i n M i n e r a l O i l Degree o f S e p a r a t i o n i n cc* i n d i f f e r e n t t im e p e r i o d s . No. Normality D A Y S 1 4 9 14 22 32 39 46 53 60 67 74 81 88 1 1 1 1 1 1 1 1 1 1 1 1 2 1o1—I no sep a r a t i o n 3 10 “2 n n 4 mT 3 TT t t 5 10 "4 tt Tt 6 10 “5 t t TT 7 10 " 6 ft rr 8 1 0 -? tt tt — 69 — Table ITo* XXV. Emulsions o f S o lu t io n of Sodium C hlo r ide in Olive O i l . Degree of s e p a r a t i o n i n cc . i n d i f f e r e n t time p e r io d s . Mo. iForm­ D A Y S a l i t y 1 ; 4 9 i 14 | 22 32 39 46 53 160 6 7 1 ! i 1 3 3 ‘ i | 3 j 3 3 3 . 3 3 \ 3 3 2 H O 1 H 1 2 2 ! 2 | 2 2 3 1 2 2 I 2 2 3 ; i o ' 1 1 1 1 i i i 1 l i i •< 1 1 1 4 1 10 1 1 1 1 1 1 1 l i i 1 1 1 Figure XVII. Emulsions of S o lu t io n s of Sodium Chloride i n M inera l O i l . 70 - I n o r d e r to s t u d y t h e i n f l u e n c e of h y d r o g e n i o n s p r o d u c e d by a s o u r c e o t h e r t h a n h y d r o c h l o r i c a c i d , s o l u t i o n s o f s u l p h u r i c a c i d were p r e p a r e d , t h e i r P d e t e r m i n e d and t h e s e were e m u l s i f i e d i n m i n e r a l o i l and o l i v e o i l * X i t h o l i v e o i l and m i n e r a l o i l t h e r e s u l t s were s i m i l a r t o t h o s e o b s e r v e d when h y d r o c h l o r i c a c i d s o l u t i o n s were e m u l s i f i e d * T a b l e s XXVI and XXVII r e c o r d t h e s e r e s u l t s . Graph number X shows t h e s t a b i l i t y o f t h e s u l p h u r i c a c i d s o l u t i o n s e m u l s i f i e d i n m i n e r a l o i l * - 71 - T ab le No* XXVI E m u ls io n s o f S o l u t i o n s o f V a r i o u s H ydrogen I o n C o n c e n t r a t i o n s i n M i n e r a l O i l* o • PH 1 2 D A Y ih r . h r s . 1 4 9 14 22 32 39 46 53 60 67 74 81 88 1 1 . 0 4 10 C.S 2 1 . 5 1 4 r*o 6 6 6 6 6 6 6 6 7 7 7 7 7 7 3 2 .1 7 1 1 1 1 1 1 1 1 1 1 1 1 1 4 3 .0 6 no s e p a r a t i on 5 4 .2 1 Tf rt 6 4 . 8 a f t "r - 72 - T a b le No. XXVII Emulsions of S o lu t io n s o f Various Hydrogen Ion C o n c e n t ra t io n s i n O l iv e O i l . ----1----- ota — i P ii 1 / 2h r . D A Y 3 1 4 9 17 27 34 41 48 55 67 69 76 8 3 1 1 . 0 4 8 8 8 8 9 9 10 C.S 2 1 . 5 1 6 7 7 7 7 7 7 7 7 7 7 7 7 7 3 2 . 1 7 2 2 3 3 3 3 3 3 3 3 3 3 3 4 3 . 0 6 2 2 3 3 3 3 3 3 3 3 3 3 3 5 4 .2 1 1 1 1 1 2 2 2 2 2 2 2 2 2 6 . 4 .8 6 1 1 1 1 1 1 1 2 2 2 2 2 2 - 73 CC. p e r ^ - ^ 11 NOfc 1Q day STABILXIY OF EMULSIONS OF SOLUH OHS OF VARIOUS HYDROGEN ION CONCENTRATIONS IN LUNNRHL OIL (Ii^SO. ) 10 IE - 74 - In o rd e r to de te rm ine w i th in a c l o s e r range the hydrogen i o n c o n c e n t r a t i o n a t which the range of i n s t a b i l i t y on the ac id s id e b e g i n s ! t h e fo l lo w in g s e r i e s of emulsions were p repared u s in g m in e ra l o i l a s the e x t e r n a l phase . Tables XXVIII and XXDC show the degree o f s e p a r a t i o n o f th e se emulsions over a p e r io d of e i g h ty t h r e e days and f i g u r e XVIII shoves the emulsions l i s t e d i n t a b le X X IX a f t er t h i r t y days. Reading from l e f t to r i g h t the emulsions i n f ig u re XVI11 are numbered as g iven i n t a b l e X X i X . , Table 'No. XXVIII. Emulsions of S o lu t io n s of Various Hydrogen Ion C oncen tra t ions In i h n e r a l Oil* Degree of S ep a ra t io n i n c c . i n d i f f e r e n t time p e r io d s . ITO. PH 1 /2h r . D A Y S 4 9 17 27 34 41 48 55 62 69 76 83 1 0*9 5 10 C.£ £ 1 ,3 6 2 . 5 3 3 3 3 3 3 3 3 o 3 3 3 3 1 . 8 7 1 1 1 1 1 1 1 1 1 1 4 2 .1 7 1 1 1 1 1 1 5 3 .0 5 - 75 - Table No* T U X Emulsions of S o lu t io n s o f Yarious Hydrogen Ion C oncen tra t ions i n Mineral O i l . Degree of S e p a r a t io n i n cc . i n d i f f e r e n t time p e r io d s .----roJ25 PH 1 /2 D A Y Sh r . 4 9 17 27 34 41 48 55 62 69 76 83 1 o>*o 5 9 9 9 9 9 9 9 9 9 9 9 9 2 1*36. 1 1 1 1 1 1 1 1 1 1 1 1 1 3 1 *8 7 1 2 2 2 2 2 2 2 2 2 2 4 2 *1 7 5 3*05 Figure m i l Emulsions o f S o lu t io n s o f Yarious Hydrogen Ion C oncen tra t ions i n Mineral Oil* - 76 - S tu d y o f t h e P h y s i c a l P r o p e r t i e s o f E m u l s io n s W a t e r - i n - O i l Type * S u r f a c e T e n s io n — The s u r f a c e t e n s i o n s o f t h e v a r i o u s e m u l s io n s o f s o l u t i o n s o f d i f f e r e n t h y d ro g e n i o n con­ c e n t r a t i o n s i n m i n e r a l o i l were m ea su re d a t 20° C. w i t h a s t a n d a r d i z e d . DuiTouy t e n s i o m e t e r . The r e s u l t s o f t h e s e m ea su re m e n ts a r e t a b u l a t e d i n t a b l e x r x % T a b le IQQC. S u r f a c e T e n s io n o f E m u ls io n s i n Ll-fneral O i l a t 20° C. !2! o • Dynes p e r cm. . . . . . . if 1 i M i n e r a l O i l 3 5 .6 2 2 0 . 9 i 3 6 .3 3 : 3 1*87 ! 3 7 .0 8 i! 4 3*97 i 3 6 .8 1 i j , 5 7*55 1 3 6 .8 1 | ; 1 ! i 6 9 .2 5 ; 3 S .4 3 j ' 7 1 0 .9 7 ! 3 6 .6 0 I ; 8 1 1 .7 5 ! i 3 7 .0 8 1 9 1 3 . 0 ] J 1 ' i 3 6 .6 4 j V i s c o s i t y - U s in g the e x t e r n a l p h a s e , m i n e r a l o i l , a s a s t a n d a r d a t 20° C*, th e r e l a t i v e v i s c o s i t i e s o f a s e r i e s o f e m u l s io n s were d e t e r m i n e d by t h e m ethod p r e v i o u s l y d e s c r i b e d . The r e l a t i v e v i s c o s i t i e s o f t h e s e e m u l s io n s showed l i t t l e v a r i a t i o n e x c e p t on 'the ex t rem e a c i d and a l k a l i n e s i d e o f the ra n g e * The r e s u l t s of t h e s e m e a su re m e n ts a r e t a b u l a t e d i n t a b l e 221 and p l o t t e d i n g r a p h X I . T a b l e XXXI R e l a t i v e V i s c o s i t i e s o f h m u ls io n s i n M i n e r a l O i l a t 20° C* id 0 1 % R e l a t i v e V i s c o s i t i e s 1 M i n e r a l O i l 243 s e c . u n i t y 2 0*9 0*106 3 1*87 0 .2 4 2 4 3*97 0*224 5 7*55 0*219 6 9*25 0*214 7 10*97 0*214 8 11*75 0.245 9 1 3 .0 0 .1 4 4 - 78 - GRAPH HO. 11 - RELATIVE VISCOSITY OF' SOLUTION'S OF VARIOUS HYDROGEN ION CONCENTRATIONS IN MINERAL OILV i s c o s i t y 25 20 15 10 TO 12 1 4 79 Size of P a r t i c l e - Emulsions of s o l u t i o n s of var ious hydrogen io n c o n c e n t r a t io n s (co lo red vdth a w a te r - s o lu b le dye) were p rep a red u s ing m in e ra l o i l a s the e x t e r n a l phase* The s iz e o f the p a r t i c l e s was measured m ic ro s co p ic a l ly * The r e s u l t s of these measurements a re g iven i n t a b l e 2QCCEI* Table m i . No* PTTii Average d iam ete r o f p a r t i c l e s i n microns 1 0*9 38*9 2 1*87 21*2 3 3*97 20*6 4 7.55 17*7 5 9*25 22*4 6 10*97 17*7 7 11*75 30.0 8 13*0 Vi o * 0 1 1 i J__ - 80 - Summary o f R e s u l t s and T h e o r e t i c a l C o n s id e ra t io n s . Em uls i fy ing Agents - v/ith m ine ra l o i l , s im i l a r to Ear Id. n s' o b s e rv a t io n w ith benzene; magnesium, ca lc ium , c o b a l to u s , n i c k e lo u s , nangaaous and aluminum o le a t e s produce emulsions of the m a t e r —i n - o i l type* With v a l e r i c ac id s im i l a r to Harkins ' and Henman's o b s e rv a t io n s with o le i c a c id , the u n iv a l e n t s a l t s produce o i l - i n - w a t e r em uls ions , vrfiereas tire s a l t s of d i v a l e n t m e ta l s produce w a t e r - i n - o i l emulsions. The s a l t s o f a rab ic ac id produce o i l - i n - w a t e r emulsions i r r e s p e c t i v e of the va lence of the m e t a l l i c atom in combination* Having dem onstra ted the amphoteric emulsion c h a r a c t e r i s t i c of the d i v a l e n t s a l t s o f a c i d s , i n which t h e r e a re s e v e ra l hydroxyl groups, i t i s e n t i r e l y p o s s ib le t h a t f o r t h i s reason a c a c i a always tends to produce an o i l - i n - w ate r emulsion* According to the o b se rv a t io n s made with o i the d i v a l e n t s a l t s Ai - g a l a c t o n i c and g luconic ac id s i t i s l i k e l y t h a t the p resence of hydroxyl groups in the mole­ cule of a r a b i c ac id i n a d d i t i o n to the f a c t t h a t a c a c ia con­ t a i n s some u n iv a l e n t s a l t s of a r a b ic a c id , a re r e s p o n s ib le f o r i t s i n v a r i a b l y p roducing emulsions of the o i l - i n - w a t e r type . As the gum t r a g a c a n th i s e s s e n t i a l l y the calcium s a l t of b a s s o r i c ac id and produces emulsions of the o i l - i n - w a t e r ty p e , i t i s l i k e l y t h a t t h i s co n d i t io n e x i s t s f o r reasons s i m i l a r to those proposed fo r the s a l t s of a rab ic ac id . According to the p o s t u l a t e s of Harkins and h i s a s s o c i a t e s , when h ie c r o s s - s e c t i o n of the hydrocarbon cha in o f an em u ls i fy in g agent and the m e t a l l i c end are of the same magnitude , th e r e i s l i t t l e o r no tendency to cu rva tu re and h e n ce no s t a b l e e m u l s i o n w i l l r e s u l t , , / i t h u n i v a l e n t s a l t s o f t h e s e a c i d s c o n t a i n i n g h y d r o x y l g ro u p s t h e p a c k i n g o f t h e e m u l s i f y i n g a g e n t m o l e c u l e s n e e d n o t be a l t e r e d b e c a u s e th e p o l a r m e t a l l i c a toms and a l s o t h e h y d r o x y l g ro u p s d i p i n t o t h e w a t e r . T hen , how­ e v e r , t h e s e compounds a r e a t t a c h e d t o a d i v a l e n t m e t a l t h e h y d r o x y l g ro u p s so i n c r e a s e th e m a g n i tu d e o f th e h y d r o c a r b o n c h a i n t h a t t h e r e i s l i t t l e t e n d e n c y t o c u r v a t u r e and th e e m u l s i o n s o b t a i n e d a r e n o t v e r y s t a b l e . I t i s p o s s i b l e t h a t t h e p r e s e n c e of so many p o l a r h y d r o x y l g ro u p s i n th e m o le c u le makes t h e p r o d u c t i o n o f e m u l s io n s o f e i t h e r t h e o i l - i n - w a t e r t y p e or the w a t e r - i n - o i l type p o s s i b l e . I t i s i n t e r e s t i n g to n o t e t h a t .YestoUjflQ) w o rk in g w i t h c o l l o i d a l c l a y s , o b se rv e d t h a t t h e s e s u b s t a n c e s would p r o d u c e e m u l s io n s o f t h e o i l - i n - v ja te r o r w a t e r - i n - o i l t y p e . i n f l u e n c e s of Changes in PH upon o i l - i n . ^ Vs ter Emul s ions The d a t a and g r a p h s c o r r e l a t i n g t h e r e s u l t s o b t a i n e d i n d i c a t e t h a t v e g e t a b l e and m i n e r a l o i l e m u l s i o n s p r e p a r e d w i th a c a c i a a r e s t a b l e o v e r a h y d r o g e n i o n c o n c e n t r a t i o n v a r y i n g f rom P^ 2 t o Pt_j 1 0 . The p r e s e n c e o f a l k a l i e s i s e s p e c i a l l y d e t r i m e n t a l to th e s t a b i l i t y o f t h e s e e m u l s i o n s . E m u ls io n s w i th a c a c i a a t v a r i o u s h y d ro g e n i o n c o n ­ c e n t r a t i o n s show l i t t l e change i n t h e i r s u r f a c e t e n s i o n s and t h e i r r e l a t i v e v i s c o s i t i e s a r e I d e n t i c a l . The s i z e o f the p a r t i c l e s i n th e a c a c i a e m u ls io n s a r e f a r more u n i f o r m and s m a l l e r t h a n t h o s e o f t h e t r a g a c a n t h em uls ions and on the a c i d and a l k a l i n e s i d e o f t h e P s c a l exi t h e r e i s a s l i g h t i n c r e a s e i n th e s i z e o f t h e p a r t i c l e . T h i s i s e x a c t l y what one would e x p e c t a s a t t h e s e p o i n t s a l s o t h e s m a l l e s t d e g r e e o f s t a b i l i t y was o b s e r v e d . I . I i c r o s c o p i c a l l y i t was o b s e r v e d t h a t t h i s i n c r e a s e i n t h e s i z e o f t h e p a r t i c l e i s due t o c o a l e s c e n c e , p r e l i m i n a r y to s e p a r a t i o n * The e m u l s i o n s p r e p a r e d w i t h t r a g a c a n t h a r e e s p e c i a l l y s t a b l e a t PT^ 1*9 to Pg 2 .3 and q u i c k l y s e p a r a t e on t h e a l k a ­ l i n e s i d e o f t h e P s c a l e . E x a m in a t io n o f Graph number IVil i n d i c a t e s t h a t t h i s r a n g e o f h y d ro g e n i o n c o n c e n t r a t i o n d o e s n o t change when th e a c i d i t y i s p r o d u c e d by s u l p h u r i c a c i d i n s t e a d of h y d r o c h l o r i c a c i d . *Ye c a n n o t , h o w ev er , c o n s i d e r t h i s a s a s p e c i f i c e f f e c t o f t h e h y d r o g e n i o n a lo n e f o r sod ium c h l o r i d e p r o d u c e s a s i m i l a r s t a b i l i t y when th e sod ium i o n c o n c e n t r a t i o n i s a b o u t 1 0 ’ % . a s o b s e r v e d i n f i g u r e X I . A s t u d y o f Graph number V I I i n d i c a t e s t h a t t h e r e i s a c o n s i d e r a b l e d ro p i n v i s c o s i t y v d t h an i n c r e a s e o f h y d r o x y l i o n c o n c e n t r a t i o n , which i s c h a r a c t e r i s t i c o f m o s t m u c i l a g i n o u s m a t e r i a l , n a m e ly , t h a t t h e p r e s e n c e o f a l k a l i r e d u c e s t h e v i s c o s i t y o f t h e g e l . T here was no change i n v i s c o s i t y i n t h e e m u l s i o n s p r e p a r e d w i t h a c a c i a . The a u t h o r f e e l s t h a t a maximum v i s c o s i t y i s n o t d e s i r a b l e a s i n d i c a t e d by g r a p h number V I I , b u t an optimum r e l a t i v e v i s c o s i t y w h ich i s found t o be be tw een 4 and 6; Holmes and C h i ld (19) w o rk in g w i th g e l a t i n s o l u t i o n s s u p p o r t t h i s v iew . I t seems t h a t i n t r a g a c a n t h e m u l s i o n s , a s o b s e r v e d by o t h e r i n v e s t i g a t o r s i n o t h e r f i e l d s , t h a t v i s c o s i t y a i d s e m u l s i f i c a t i o n s o l e l y by v i r t u e o f th e h i n d r a n c e o f f e r e d t o a g g l u t i n a t i o n o f the o i l p a r t i c l e s . G-raph V shows t h a t t h o s e e m u l s i o n s p r e p a r e d w i t h t r a g a c a n t h d e c r e a s e i n s u r f a c e t e n s i o n to w a rd t h e a l k a l i n e s i d e o f t h e s c a l e . The a u t h o r , how ever , d o e s n o t c o n s i d e r t h e phenomenon o f s u r f a c e t e n s i o n o f p a ram o un t im p o r t a n c e i n v iew o f t h e p o s t u l a t e s o f L angm uir (20) who s t a t e s t h a t s i m i l a r l i q u i d s may have t h e same s u r f a c e t e n s i o n a g a i n s t a i r , owing to t h e f a c t t h a t i n t h e i r s u r f a c e l a y e r s i m i l a r g ro u p s o r atoms may be s i m i l a r l y o r i e n t e d . The i n t e r f a c i a l t e n s i o n o f t h e two l i q u i d s h a s b e e n u s e d by some a s a m ea su re of the e m u l s i f y i n g power o f one l i q u i d upon a n o t h e r . A c c o r d i n g l y t h i s m easurem ent was a t t e m p t e d b e tw e e n m i n e r a l o i l and t r a g a c a n t h g e l s o f v a r i o u s h y d r o g e n i o n c o n c e n t r a t i o n s . I n v a r i a b l y a s t e a d y s t r e a m was o b t a i n e d i n s t e a d of d ro p s as was o b t a i n e d by Donnan (21) w i th s o l u t i o n s o f t h e sodium s a l t s o f c e r t a i n h i g h m o l e c u l a r w e ig h t f a t t y a c i d s . The i n t e r f a c i a l t e n s i o n o f m i n e r a l o i l and s o l u t i o n s o f v a r i o u s h y d ro g en i o n c o n c e n t r a t i o n s a s p l o t t e d i n g ra p h VI show t h a t t h e a l k a l i n e s o l u t i o n s r e d u c e th e i n t e r f a c i a l t e n s i o n which sh o u ld i n c r e a s e t h e power o f e m u l s i f i c a t i o n ^ were t h e e m u l s i f y i n g a g e n t n o t a f f e c t e d . I t i s c o n c lu d e d t h e r e f o r e t h a t t h e chan ges i n h y d ro g e n i o n c o n c e n t r a t i o n i n f l u e n c e t h e perm anency o f t h e g e l and t h u s a f f e c t t h e s t a b i l i t y o f t h e e m u l s i o n . A c l o s e e x a m i n a t i o n o f f i g u r e XIY w i l l show t h a t o n l y t h o s e t r a g a c a n t h g e l s b e tw ee n Prr 0*4 and 2*1 r e m a inH f r e e f r c m t h e s e p a r a t i o n o f w a t e r a t t h e s u r f a c e , o r i n o t h e r words t h e l i q u i d s b e tw e e n P ^ 1 and 2*1 p r e p a r e t h e most s t a b l e g e l s w i t h t r a g a c a n t h ; i t w i l l be r e c a l l e d t h a t t h e s t a b l e r a n g e o f f o r e m u l s io n s made w i th t r a g a c a n t h p r a c t i c a l l y l i e s w i t h i n t h i s s c a l e * T h i s s u p p o r t s F i s c h e r * s (22) 1-Iydrate t h e o r y o f e m u l s i f i c a t i o n , w h ich p o s t u l a t e s t h a t o i l i s m ost p e r m a n e n t l y e m u l s i f i e d i n a h y d r o p h i l e c o l l o i d when j u s t a s u f f i c i e n t amount o f w a t e r i s p r e s e n t t o fo rm a h y d r a t e . I t i s b e l i e v e d t h a t w i t h t r a g a c a n t h t h i s amount of \ r a t e r i s a f u n c t i o n of i t s hydrogen i o n c o n e e n t r a t i o n ^ t h e r e f o r e a t t h e r a n g e o f t h e P,_ s c a l e where t r a g a c a n t h shows i t s e l f to p o s s e s s t h e h i g h e s t d e g r e e of h y d r a t a b i l i t y , t h i s r a n g e i s t h e s t a b l e p o i n t f o r e m u ls io n s p r e p a r e d w i t h t h i s c o l l o i d . P I n f l u e n c e s o f Changes i n H upon h a t e r - i n - O i l E m u l s i o n s . A s t u d y o f t h e g r a p h s showing t h e s t a b i l i t y o f th e e m u l s i o n s i n m i n e r a l o i l and o l i v e o i l ( g r a p h s T i l l and IX) i n d i c a t e t h a t t h e m os t s t a b l e r a n g e o f h y d ro g e n i o n c o n c e n ­ t r a t i o n f o r t h e i n t e r n a l p h a s e o f t h e s e e m u l s io n s l i e s w e l l on t h e a l k a l i n e s i d e o f the P-n- s c a l e . The PTT r a n g e a t Y /h ic hid H t h e e m u l s i o n s were m ost s t a b l e was b e tw e e n 11 and 1 2 .5 * From m o d e ra te PT_£ 11 to 2 .5 t h e r e i s a r a n g e o f / s t a b i l i t y , w h e re a s f rom P-jtj 2*5 t o P 0*9 raay be l o o k e d upon as t h e r a n g e o f e x t rem e i n s t a b i l i t y . 'Tith f r e s h l y p r e c i p i t a t e d magnesium o l e a t e t h e r e i s l i t t l e o r no s e p a r a t i o n f ro m P^ 2 . 5 to 1 1 b u t t h e f i e l d J . J . o f i n s t a b i l i t y i s on t h e a c i d side, o f PTT 2 . 5 and t h e maximumli p o i n t o f s t a b i l i t y l i e s b e tw e e n Pp 11 and 1 2 . 5 . YiTith m i n e r a l o i l and o l i v e o i l t h e s i m i l a r o b s e r v a t i o n s were made i f t h e h y d ro g e n i o n c o n c e n t r a t i o n was p r o d u c e d by t h e a d d i t i o n o f s u l p h u r i c a c i d i n d i c a t i n g t h a t t h e i n s t a b i l i t y was due to t h e p r e s e n c e o f a h i g h h y d r o g e n i o n c o n c e n t r a t i o n . \ 7/hen v a r i o u s c o n c e n t r a t i o n s o f s o l u t i o n s o f sodium c h l o r i d e were e m u l s i f i e d , t h e r e was no i n f l u e n c e i n s t a b i l i t y a s f a r a s e m u l s i o n s i n m i n e r a l o i l were c o n c e r n e d , b u t w i t h t h o s e d i s p e r s e d i n o l i v e o i l t h e i n s t a b i l i t y o f t h e e m u l s io n s • i n c r e a s e d w i t h t h e i n c r e a s e o f c o n c e n t r a t i o n o f sodium c h l o r i d e i n the d i s p e r s e d p h a s e . A s t u d y o f t h e p h y s i c a l p r o p e r t i e s o f t h e e m u ls io n s shows t h a t as f a r a s s u r f a c e t e n s i o n i s c o n c e rn e d ( t a b l e XXX) t h e r e i s no s i g n i f i c a n t d i f f e r e n c e i n any o f t h e e m u l s i o n s . V i s c o s i t 37- m ea su re m e n ts show ( t a b l e SZXXE) t h a t t h e e m u l s io n s o f l i q u i d s o f v a r i o u s h y d ro g en i o n c o n c e n t r a t i o n s i n m i n e r a l o i l a r e f a r l e s s v i s c o u s t h a n th e e x t e r n a l p h a s e a lo n e * On t h e ex t re m e a c i d and a l k a l i n e s i d e s o f t h e Pp s c a l e (Pp. 0 . 9 and P 13) t h e r e was a marked d rop i n v i s c o s i t y . I t i s o fXI i n t e r e s t t o n o t e t h a t t h e s e e m u l s io n s o f e x t re m e low v i s c o s i t y were t h o s e which 'were l e a s t s t a b l e . The s i z e o f t h e p a r t i c l e s o f t h e e m u l s io n s i n m i n e r a l o i l i n c r e a s e d on t h e a l k a l i n e s i d e o f t h e P s c a l e w i t h o u tri any a p p r e c i a b l e i n f l u e n c e upon s t a b i l i t y , t h e u n s t a b l e e m u l s io n o f an i n t e r n a l p h a s e o f P 0 . 9 had p a r t i c l e s which were l a r g e r t h a n t h o s e i n any o f t h e o t h e r e m u l s i o n s . A c a r e f u l m i c r o s c o p i c s t u d y o f t h e s i z e o f th e p a r t i c l e s i n r e l a t i o n t o s t a b i l i t y showed t h a t i n o a u l s i o n s , when t h e a v e r a g e s i z e o f t h e p a r t i c l e s was b e tw ee n 17 and 30 m i c r o n s , t h e r e was no i n f l u e n c e i n s t a b i l i t y , p a r t i c l e s above 30 m i c r o n s ( a v e r a g e s i z e ) t e n d t o c o a l e s c e and s e p a r a t e a s a l a y e r b e n e a t h . I t i s l i k e l y t h a t th e m os t i m p o r t a n t f a c t o r i n th e d e t e i m i n i n g o f t h e s t a b i l i t y o f t h e s e e m u ls io n s i s t h e i n f l u e n c e o f t h e h y d r o g e n i o n c o n c e n t r a t i o n o f t h e d i s p e r s e d p h a s e upon th e m agnesium o l e . a t e . The magnesium atoms d ip down i n t o t h e a q u e o u s p a r t i c l e s and when the h y d ro g e n i o n c o n c e n t r a t i o n o f t h e aqueous p h a s e i s h i g h enough Pp 2 . 5 , t h e r e i s a g r a d u a l d e c o m p o s i t i o n o f t h e e m u l s i f y i n g a g e n t w h ich r e s u l t s u l t i m a t e l y i n t h e d i s i n t e g r a t i o n o f t h e e m u l s i o n . ConclusL o n s . 1 . The c h a r a c t e r o f e m u l s i o n s p r o d u c e d by s e v e r a l o l e a t e s , c e r t a i n u n i v a l e n t an d d i v a l e n t s a l t s o f a r a b i c a c i d and some r e l a t e d compounds h a s b e e n s t u d i e d . An e x p l a n a t i o n f o r t h e i n v a r i a b l e o i l - i n - w a t e r n a t u r e o f e m u l s io n s p r e p a r e d w i t h a c a c i a and t r a g a c a n t h h a s b e en p r o p o s e d . 2 . The r a n g e o f g r e a t e s t s t a b i l i t y f o r e i t h e r v e g e t a b l e o r m i n e r a l o i l e m u l s i o n s p r e p a r e d w i t h a c a c i a l i e s b e tw ee n Pjj 2 t o 10 and w i t h t r a g a c a n t h t h e r a n g e i s PH 1 .9 to .2*3. 3 . The s i z e o f t h e p a r t i c l e s , s u r f a c e t e n s i o n , i n t e r f a c i a l t e n s i o n s and v i s c o s i t y have b e e n d e t e r m i n e d a t v a r i o u s p o i n t s on t h e Pg- s c a l e . Changes i n p a r t i c l e s i z e and v i s c o s i t y i s c a u s e d by c h a n g in g th e h y d ro g en i o n c o n c e n t r a t i o n o f e m u l s i o n s p r e p a r e d w i t h t r a g a c a n t h . The v i s c o s i t i e s o f a c a c i a e m u l s io n s a r e n o t a l t e r e d by c h a n g in g t h e P ^ , t h e s i z e o f t h e p a r t i c l e , h o w e v e r , i n c r e a s e s on th e a l k a l i n e s i z e o f t h e PT_T s c a l e . 4 . P i s c h e r f s H y d r a te t h e o r y i s s u b s t a n t i a t e d i n e m u l s io n s p r e p a r e d w i t h t r a g a c a n t h . 5 . H i t h w a t e r - i n - o i l e m u l s i o n s p r e p a r e d w i t h magnesl mu o l e a t e , o l i v e o i l i s found t o be a more s t a b l e d i s p e r s i o n p h a s e th a n m i n e r a l o i l . The most s t a b l e r a n g e o f h y d ro g e n i o n c o n c e n t r a ­ t i o n was f o u n d t o be b e tw e e n 11 and 12.S3. J i t h a h y d ro g en i o n c o n c e n t r a t i o n more a c i d i c t h a n P 2 . 5 , e x t rem e i n s t a b i l i t yH was o b se rv e d * 6 . .71 t h e m u l s io n s o f the w a t e r - i n - o i l type chan ges i n P^ o f J .J . — qq - t h e i n n e r p h a s e d i d n o t a f f e c t t h e s u r f a c e t e n s i o n , t h e u n s t a b l e e m u l s i o n s had a l o w e r v i s c o s i t y t h a n th e s t a b l e o n e s and t h e s i z e o f the p a r t i c l e s does n o t a l t e r tlhe s tab il i ty up to 50 m ic r o n s a v e r a g e s iz e * - B9 B ib l io g r a p h y » 1* H ark ins e t a l . * - J* Am. Chem. Soc. 39_ 353, 541. (1917)* 2. Langmuir, J* Am. Chem* Soc. 39 1848 (1917). 3* LTevmian - 1* Phys. Chem. 193 34 (1914)* 4 . C a s p a r i r s T r e a t i s e on Pharmacy . Lea and F e b ig e r , P . 73 7. 5* Simon's Llanual on Chemistry tr " n P. 510. 6* Dorland Lied. D ie t . .7. 3. Saunders P. 72. 7. P r a c t i c e of Pharm. Kemington J . 3 . 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