Pesticide Formulations - ACS Publications - American Chemical Society

Chapter 14

Determination of Cohesive Energy Density Parameters for Developing Pesticide Formulations Kenneth E. Meusburger

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Thompson-Hayward Chemical Company, Kansas City, KS 66106 The art of developing agricultural pesticide formulations requires an understanding of the interactions of solute and solvents, of colloidal particles and surface active agents, and of liquids and emulsifiers. The applications of the concepts of Cohesive Energy Density is of value in increasing one's understanding of these phenomena. Detailed explanations of the Cohesive Energy Density principles and concepts are presented in current literature. When applying these concepts the practitioner will on occasion encounter organic compounds or aqueous solutions for which he will not find accurate CED values. This paper will demonstrate methods which can be used in determining these parameters and data points. The first section includes unpublished data calculated by the late Dr. Allen Beerbower, as well as by this author. The second section deals with a method for the determination of the Cohesive Energy Density values of inorganic aqueous solutions. The p i o n e e r r e s e a r c h e r s i n t h e f i e l d o f " C o h e s i v e E n e r g y D e n s i t y " ( C . E . D . ) have b e e n f e w . I n 1986 we l o s t a d e d i c a t e d and b r i l l i a n t w o r k e r i n C . E . D . r e s e a r c h , D r . A l l e n A . Beerbower. A t h i s w i s h t h i s u n p u b l i s h e d work c o n c e r n i n g t h e m o l e c u l a r group c o n t r i b u t i o n s i s presented, t o g i v e those pursuing C . E . D . research access to h i s expanded d a t a b a s e . T h i s p a p e r i s d e d i c a t e d t o D r . A l l e n Beerbower and i s a r e s u l t o f p e r s o n a l communiques f r o m h i m . He s p e n t many o f h i s p o s t retirement years developing the data i n Table I . The p r i n c i p l e s o f C . E . D . were f i r s t propounded b y H i l d e b r a n d ( 1 ) d u r i n g h i s r e s e a r c h i n t o t h e p r i n c i p l e s g o v e r n i n g s o l u b i l i t y . He found t h a t d i v i d i n g t h e h e a t o f v a p o r i z a t i o n by t h e m o l a r volume o f a s o l v e n t y i e l d e d a meaningful parameter f o r comparative purposes. I f t h e p a r a m e t e r s o f two l i q u i d s a r e w i t h i n + 2 H i l d e b r a n d s t h e s o l v e n t s a r e m i s c i b l e . Hansen (2) found t h a t s o l i d s c o u l d b e i n c l u d e d and a c c u r a c y i n c r e a s e d b y e x p a n d i n g t h e b u l k p a r a m e t e r f r o m 0097-6156/88A)371-0151$06.00A) ° 1988 American Chemical Society

Cross and Scher; Pesticide Formulations ACS Symposium Series; American Chemical Society: Washington, DC, 1988.

152

PESTICIDE FORMULATIONS: INNOVATIONS AND DEVELOPMENTS

a s i n g l e t o a three-pararaeter system. A g a i n , i f the s e t o f t h r e e p a r a m e t e r s f o r two s u b s t a n c e s a r e c l o s e , t h e m a t e r i a l s w i l l d i s s o l v e i n e a c h o t h e r . Beerbower i m p r o v e d t h e q u a l i t a t i v e n a t u r e o f t h e s e p a r a m e t e r s . The r e s u l t s were more q u a n t i t a t i v e t h a n s u s p e c t e d , a l l o w i n g h i m t o d e f i n e , n u m e r i c a l l y , t h e n a t u r e o f e m u l s i o n s and surfactants. E x t e n d i n g B e e r b o w e r s method 03) g i v e s a d e s c r i p t i v e surfactant s e l e c t i o n procedure. H i e t e c h n i q u e was f u r t h e r r e f i n e d i n t o a s u r f a c t a n t "near neighborhood" o p t i m i z a t i o n procedure as d e s c r i b e d i n "Computer O p t i m i z a t i o n o f B n u l s i f i e r s f o r P e s t i c i d e E m u l s i f i a b l e C o n c e n t r a t e s " . (4) I n t u i t i o n i s t h e s t r o n g r i g h t arm o f t h e e x p e r i e n c e d , b u t f a i l s t h e n o v i c e a n d t h o s e who s e a r c h f o r t h e p r i n c i p l e s w h i c h g o v e r n t h e a r t o f f o r m u l a t i o n . Those who u s e C . E . D . a s a n e n g i n e e r i n g a p p r o x i mation f o r chemical formulations are seeking a r a t i o n a l s t a r t i n g p o i n t . One o f t h e m a i n d i f f i c u l t i e s i n u s i n g t h i s p r o c e d u r e i s d e t e r m i n i n g C . E . D . p a r a m e t e r s . T h i s p a p e r p r e s e n t s one a p p r o a c h t o a l l e v i a t i n g some o f t h a t d i f f i c u l t y i f c h e m i c a l s t r u c t u r e s a r e known.


1

D e t e r m i n a t i o n o f C . E . D . Parameters from Chemical S t r u c t u r e s W i t h T a b l e I o f n o l e c u l a r / c h e m i c a l group v a l u e s , the r e s e a r c h e r i s a b l e t o use a c h e m i c a l s t r u c t u r e t o develop a f u n c t i o n a l s e t o f C . E . D . p a r a m e t e r s . The p r a c t i t i o n e r c a n t h e n d e t e r m i n e a p p r o x i m a t e values f o r the heat o f v a p o r i z a t i o n , b o i l i n g p o i n t , s p e c i f i c g r a v i t y , solvency/solubility, emulsifiability, etc. A problem encountered i n developing Table I concerned the e v o l u t i o n o f t h e C . E . D . p a r a m e t e r s . The t h r e e b a s e v a r i a b l e C . E . D . s y s t e m was p u b l i s h e d o r i g i n a l l y b y Hansen (2) a n d p r e s e n t e d a s e t o f parameters for various materials. H a n s e n ' s a p p r o a c h was b a s e d o n t h e heat o f v a p o r i z a t i o n , s o l u b i l i t y o f solvents w i t h selected polymers, and p h y s i c a l p r o p e r t i e s . A second c o m p l e t e s e t o f p a r a m e t e r s f o r a w i d e v a r i e t y o f s o l v e n t s was l a t e r c o - a u t h o r e d b y Hansen and B e e r b o w e r , p u b l i s h e d i n t h e " E n c y c l o p e d i a o f C h e m i c a l T e c h n o l o g y " (9) i n 1 9 7 1 . The Hansen and Beerbower method o f d e v e l o p i n g C . E . D . parame t e r s i n v o l v e d a p h y s i c a l - c h e m i c a l b a s i s and s t a t i s t i c a l l y cannbining t h e d a t a w i t h e x p e c t e d h e a t s o f v a p o r i z a t i o n . T h e i r 1971 a r t i c l e (as n o t e d i n a p e r s o n a l communique f r o m C h a r l e s Hansen) was a comprom i s e o f t h e s e two methods. L a t e r , Hoy p u b l i s h e d a t h i r d s e t o f v a l u e s . A l l t h r e e s e t s o f C . E . D . parameters are i n c l u d e d i n A l l a n F.M. B a r t o n ' s p u b l i c a t i o n . (5) I t i s t h i s a u t h o r ' s e x p e r i e n c e t h a t t h e s e s e t s o f v a l u e s a r e a c c u r a t e enough f o r most e m u l s i o n a n d e m u l s i f i e r s e l e c t i o n w o r k . T a b l e I was b a s e d o n a l l t h r e e d a t a s e t s a n d y i e l d s r e s u l t s o n t h a t compromise b a s i s . (Refer t o T a b l e I , a n d accompanying Figures.) C . E . D . Paramaters f o r Strong E l e c t r o l y t e S o l u t i o n s The s e c o n d p a r t o f t h i s p a p e r d e v e l o p s a m a t h e m a t i c a l b a s i s f o r t h e d e t e r m i n a t i o n o f C . E . D . p a r a m e t e r s f o r aqueous s o l u t i o n s o f m u l t i v a l e n t , s t r o n g e l e c t r o l y t e s ; and d e m o n s t r a t e s t h e a c c u r a c y o f t h e p r o p o s e d method b y e v a l u a t i n g s u r f a c e t e n s i o n d a t a f o r a s e r i e s o f d i s s i m i l a r i o n i c specie solutions.


14.

Cohesive Energy Density Parameters

MEUSBURGER

153

The f i r s t s t e p i n d e t e r m i n i n g t h e C . E . D . f o r s t r o n g e l e c t r o l y t e s o l u t i o n s i s t o determine a n average o r apparent molar volume. T h i s i s approxairated u s i n g t h e f o l l o w i n g p r o c e d u r e : Assume t h e h y d r a t e d i o n s a r e s p h e r i c a l a n d d e t e r m i n e t h e i r volume f r a c t i o n . T h i s i s done u s i n g t h e E i n s t e i n e q u a t i o n based o n v i s c o s i t y o f an e l e c t r o l y t e s o l u t i o n . H i s equation i s expressed a s : * -

(v/v

0

- 1.0)/2.5

(1)

where f i s t h e volume f r a c t i o n o f t h e h y d r a t e d i o n s i n t h e water s o l u t i o n , v equals t h e s o l u t i o n v i s c o s i t y and v equals v i s c o s i t y o f water a t 2 0 ° Centigrade.


0

I f we c o n s i d e r t h e volume o f 1 0 0 0 . 0 grams o f s o l u t i o n (1000.0/dp) m u l t i p l i e d b y t h e volume f r a c t i o n o f t h e h y d r a t e d i o n s (), we o b t a i n t h e volume o c c u p i e d b y t h e h y d r a t e d i o n s . Thus t h e e x p r e s s i o n i s f o r m e d : V j = MN x VMSW =

(1000.0/drp) x $

(2)

where d j = d e n s i t y a t 2 0 / 4 Vj4s^ i s t h e a v e r a g e m o l a r v o l u m e . The number o f m o l e s o f t h e i o n s p e c i e s (%) i s d e t e r m i n e d d i r e c t l y b y a c a l c u l a t i o n b a s e d on the freeze p o i n t depression. The u s u a l arrangement o f t e r m s i s as follows: F

D

= K x (1000) x (G2/G!) x F

ftfe)

(3)

where Frj e q u a l s t h e f r e e z e p o i n t d e p r e s s i o n a n d ¥p i s a f a c t o r , u s u a l l y 1.86, G2 equals t h e weight o f s o l u t e , G i equals the weight o f solvent, and H 2 equals molecular weight of material i n question. By a r e a r r a n g e m e n t o f t e r m s a n d o n l y s l i g h t m o d i f i c a t i o n o f s a l t a d d i t i o n , we o b t a i n t h e f o l l o w i n g e x p r e s s i o n : G2/M2 = % = F

D

x G]/(KF x

(1000.0))

=

(4)

(FD) x (1000.0 - 1 0 . 0 x P S ) / ( K F ) x 1 0 0 0 . 0 where P g i s t h e p e r c e n t s a l t i n t h e s o l u t i o n . Now combine e q u a t i o n s 1 a n d 4 t o d e t e r m i n e t h e a v e r a g e m o l a r volume o f t h e h y d r a t e d i o n s : = ( i . o / % ) x (MN) x ( v ^ w )

(5)

The m o l e s o f w a t e r (%) n o t bound b y h y d r a t i o n i s c a l c u l a t e d d i r e c t l y by t h i s expression: %

=

(1000.o/dr - %

x VMSNJ/IS.OIS


(6)

154


Table I. Molecular Group Contributions for Molecular Volume and Cohesive Energy Parameters Group % V VxD VxP Vx(H2)

Group Name o r Chemical Composition Molecular Weight Apparant Molar Volume Molar Volume m u l t i p l i e d by C.E.D. Dispersion Parameter Molar Volume m u l t i p l i e d by C.E.D. P o l a r i t y Parameter Molar Volume m u l t i p l i e d by C.E.D. Hydrogen Bonding Parameter Squared

(Temperatures assumed t o be 25 Degrees Centigrade but not specified) Downloaded by CORNELL UNIV on October 11, 2016 | http://pubs.acs.org Publication Date: June 24, 1988 | doi: 10.1021/bk-1988-0371.ch014

GROUP -CH3

-CH >CH>C< =CH =CH=C< 5/6 Ring Conj - Chain C i s - Configuration Conj - Ring -0>C=0 -OCO>P04-CN -N02 -NH2 -NH>N-N= -GONH-CON< -QH -OOOH >SiCK -CL -CL Aromatic (-CL)2 Adjacent >C=0 -F -BR -BR Aromatic (-BR)2 Adjacent -I -COO- Ester -COO E s t e r Aromatic -O-0- Aromatic 2

2

2

%

V

VxD

VxP

Vx(H )

15.038 14.027 13.019 12.011 14.027 13.019 12.011 0.000 0.000 0.000 0.000 15.999 28.011 44.011 95.974 26.011 45.998 16.016 15.008 14.000 14.000 43.018 42.010 17.008 45.018 44.085 35.453 35.453 70.906 28.011 18.998 79.904 79.904 159.808 126.904 44.009 44.009 15.999 15.999

31.737 16.572 -1.000 -19.200 32.100 12.400 -5.700 13.500 -1.700 0.000 0.800 3.800 10.545 18.959 28.000 22.400 24.000 17.930 4.500 -9.000 4.000 16.800 13.200 10.465 27.834 3.800 25.300 24.000 51.200 10.000 18.000 29.000 30.000 54.000 32.200 8.200 8.200 3.600 3.800

205 132 39 -34 197 109 22 93 0 -200 21 49 142 191 362 210 244 181 78 15 80 252 147 103 259 130 205 161 440 142 108 258 269 538 320 326 326 115 49

0 0 0 0 46 34 34 0 0 0 0 196 376 239 489 538 523 205 103 73 647 621 601 244 205 150 300 269 538 376 265 300 196 454 325 250 250 200 196

0 0 0 0 70 70 70 0 275 0 -111 717 478 1672 3106 597 358 1574 741 179 860 2926 2333 4778 2389 450 100 38 430 478 0 500 215 1576 1000 1250 800 1150 717


14.

MEUSBURGER


155


Table I. Continued

% -NH2 Amide -SPhenylPhenyl< -NO2 Aromatic -NH- Aromatic >N- Aromatic >C03 >C03 Ring HCOO Formate -COO-CO Anhydride

15.018 32.064 77.107 76.099 45.998 15.008 14.000 60.008 60.008 44.009 72.019

V 25.100 8.000 75.400 60.400 24.000 4.500 -9.000 22.000 22.000 32.500 30.000

VxD

VxP

Vx(H )

327 222 733 645 244 78 15 313 372 265 330

500 177 59 65 523 103 73 108 747 121 538

2700 108 100 100 358 741 179 1098 462 1577 2365

2

See Figure 1, which demonstrates the use of Table I and illustrates the accuracies that can be expected.



156

NO. x Group

%

2x(-CH ) 6x(-CH -)

2x(15.038 +6x(14.027 114.238

3

9

V

VxD

VxP

31.737 16.572 162.906

205 132 1202

0 0 0

For N-Octane Densit^^g/V^ a t 20/4, D=VxD/vfy/


N-Octane Calculated Reported By;

Density .701

2

Vx(H ) 0) 0) 0

P=VXP/V^

2

/

H=Jvx(H )/V , w

D 7.38

P 0

H 0

7.5

0

0

(1.) Density as found i n "Handbook of Chemistry and Physics 53 Edition" (7)

.703*

(2.) "CRC Handbook of Solu b i l i t y Parameters and other cohesion parame ters" @ 25°C. Hoy(5)

.698

(3.) "Encyclopedia of Chemical Technology" @ 25°C. Hansen-Beerbower(9)

.699

7.6

0

0

.601

6.98

0

0

.601 .572 .573

6.6 6.9

0 0

0 0

.726

7.48

0

0

.730 .725 .726

7.72 7.7

0 0

0 0

N-Butane

CH (CH ) 2 C H 3 3

2

(1.) Density (2.) Hoy (3.) Hansen-Beerbower Decane

CH3 (CH2) 8CH3

(1.) Density (2.) Hoy (3.) Hansen-Beerbower

1.118

8.47

2.9

1.1


1.106 1.098 1.102

8.50 9.3

4.5 2.1

0.0 1.0

Chloroform

1.342

5.16

6.4

3.5


1.446 1.477 1.479

5.38 8.7

6.7 1.5

3.1 2.8

1,4 Dioxane

1.192

8.47

5.3

4.4


1.034 1.028 1.028

8.0 9.3

4.9 .9

3.4 3.6

Monochlorobenzene

•Densities standardized a t 20/4 degrees Centigrade except N-Butane where the density i s standardized a t 0/4 As demonstrated, the Beerbower table i s a compromise between the e a r l i e r Hansen & Beerbower data set and the later Hoy parameters as reported by Barton. Figure 1. Calculated Molecular Volume and C E D Parameters Using Table I and Comparisons with Reported Values.


14.


MEUSBURGER

157

We a r e now a b l e t o c a l c u l a t e t h e m o l e f r a c t i o n s (Xg) o f t h e h y d r a t e d s a l t i o n s and t h e r e m a i n i n g w a t e r Qfy) i n t h e s o l u t i o n as:

Xs - » W ( % + % ) ; Xw = ( % ) / ( % + % ) where:

(7)

X g + 3fy = 1 . 0

(8)

W i t h t h e s e v a l u e s we c a n d e t e r m i n e a n a v e r a g e m o l a r volume f o r t h e aqueous s a l t s o l u t i o n b y t h e e x p r e s s i o n : V

S

=

(Xs)

x

(VMSN) +

0fy)x


where 1 8 . 0 1 8 i s t h e m o l a r volume o f

(18.018)

(9)

water.

The second s t e p i n d e t e r m i n i n g t h e C . E . D . p a r a m e t e r s i s t o c a l c u l a t e t h e h e a t o f v a p o r i z a t i o n f o r a n aqueous s y s t e m . Since s a l t i n s o l u t i o n n o r m a l l y changes t h e v a p o r p r e s s u r e o f t h e w a t e r , t h i s i s used as the key t o determining a heat o f v a p o r i z a t i o n o f the aqueous s y s t e m . T o r q u a t o and S t e l l ' s (6) d e r i v a t i o n s e r v e s a s a b e g i n n i n g model f o r a m i x t u r e o f benzene and c a r b a z o l e . This author proposes modifying t h e i r equation, t o develop the e x p r e s s i o n :

%

=

( V ^ W ) x DHW - (K) x ((VsAW) x (DHN (V ) S

x

(10)

(Dag))

where: % V

= h e a t o f v a p o r i z a t i o n o f t h e s a l t s o l u t i o n (AHy) S

%

= t h e m o l a r volume o f t h e s a l t

solution

= t h e m o l a r volume o f w a t e r

PHW = t h e h e a t o f v a p o r i z a t i o n o f w a t e r (as b a c k c a l c u l a t e d from Beerbower's C . E . D . parameters) K = a calculated equilibrium constant Djjg = a m o d i f i e d C l a u s i u s - C l a p e y r o n h e a t o f v a p o r i z a t i o n value f o r the s a l t s o l u t i o n . PHS i s d e t e r m i n e d u s i n g t h e v a p o r p r e s s u r e , a t a s a l t s o l u t i o n t e m p e r a t u r e e q u a l t o o r l e s s t h a n b o i l i n g , d e s i g n a t e d a s P i . Use t h e steam t a b l e s (7) t o d e t e r m i n e t h e t e m p e r a t u r e o f w a t e r c o r r e s p o n d i n g t o p r e s s u r e P i , and l a b e l t h a t temperature a s T i - N e x t l o c a t e t h e p o i n t i n t h e steam t a b l e w h i c h i s n e x t t o P i , T i and u s e t h a t p o i n t a s P 2 / T 2 - Then i n s e r t t h e s e d a t a p o i n t s d i r e c t l y i n t o the C l a u s i s - Clapeyron equation t o g i v e a modified heat o f v a p o r i z a t i o n f o r s a l t water.


158


To change t h e m o d i f i e d h e a t o f v a p o r i z a t i o n t o t h e n o r m a l v a l u e , a c o n s t a n t was i n t r o d u c e d t o y i e l d (K x A % ) = DHSThe e q u i l i b r i u m c o n s t a n t (K) i s r e l a t e d t o t h e p r e s s u r e , t e m p e r a t u r e , s o l u b i l i t y , and i o n i z a t i o n o f t h e s a l t i n s o l u t i o n , and c a n be expressed as: Ln(K)

= AQ - A i / ( R ) x (A ) 3

x

(T) + ( A ) x 2

(T/R) + ( A 4 ) / ( 2 ) x

(Ln (T/R)) + (R) x

(12)

2

(T )

E q u a t i o n 12 was d e r i v e d b y Adamson (8) and c a n be s i m p l i f i e d K = EXP (AQ - A / T + ( A ) x


x

2

(A4)/(T )

2

(Di(T) ) + ( A ) x 3

(T) +

= K

x

(13)

)

U s i n g Admason's e x p r e s s i o n , t h e h e a t o f v a p o r i z a t i o n f o r water i s : %

as:

(DHW -

salt

14

%S)

< >

where D^q i s t h e h e a t o f v a p o r i z a t i o n o f w a t e r n e a r t h e t e m p e r ature i n consideration. Now t h a t t h e p a r a m e t e r s have been s e t f o r t h e e q u i l i b r i u m c o n s t a n t , we a r e r e a d y t o c a l c u l a t e a s e t o f C . E . D . p a r a m e t e r s f o r t h e e l e c t r o lyte solutions. I t was f o u n d f r o m t h e s a l t d a t a t h a t : K * ( (T - T ) / T )

2

0

x 18.018 x ( E X P ( - 4 . 0 x M) )

(15)

E q u a t i o n 15 has o n l y one c o n s t a n t , TQ = 2 7 3 . 1 5 , w i t h T b e i n g t h e a v e r a g e t e m p e r a t u r e i n d e g r e e s K e l v i n and M e q u a l i n g t h e m o l a r concentration. E q u a t i o n 14 was combined t o f o r m a m o d i f i e d h e a t o f v a p o r i z a t i o n . The h e a t o f v a p o r i z a t i o n v a l u e i s u s e d t o c a l c u l a t e a C . E . D . v a l u e f o r s a l t w a t e r u s i n g Beerbower s e x p r e s s i o n : 1

6

2

= (% - R x T ) / V

(16)

M

A d j u s t m e n t o f t h e h e a t o f v a p o r i z a t i o n f o r w a t e r i s needed s o t h a t a r a t i o o f volume t o volume b a s i s i s m a i n t a i n e d . This i s accomplished by m u l t i p l y i n g the c a l c u l a t e d heat o f v a p o r i z a t i o n f o r w a t e r b y t h e r a t i o o f t h e c a l c u l a t e d m o l a r volume o f t h e s a l t s o l u t i o n , t h e n d i v i d i n g b y t h e m o l a r volume o f w a t e r . Thus t h e v a l u e for the heat o f v a p o r i z a t i o n i s expressed as:

Px = (PHW " PHS) x ( V ) x K x (VsAW) S

PH =

(D^) x

(Vs/V ) W

- Px

(17) (18)

We c a n now c a l c u l a t e t h e t o t a l s o l u b i l i t y p a r a m e t e r v a l u e f o r the s a l t s o l u t i o n by the expression: 6

2

= ( ( % ) -

(R) x

(T) ) / V

S


(19)

14.


MEUSBURGER

159

The Hansen d i s p e r s i o n p a r a m e t e r ( 6 ) i s c a l c u l a t e d w i t h t h e e x p r e s s i o n d e r i v e d b y Beerbower u s i n g t h e r e f r a c t i v e i n d e x v a l u e . The p u b l i s h e d e x p r e s s i o n i s : D

6

D

= 4 . 2 2 x ( n £ - 1.0) + 3.746 + . 5

(20)

(4.32 was u s e d f o r t h e s o l u t i o n c a l c u l a t i o n s )


where nrj e q u a l s t h e r e f r a c t i v e i n d e x a t 2 0 ° C e n t i g r a d e . The c a l c u l a t i o n s g i v e a r e a s o n a b l e d a t a f i t when u s i n g a s l i g h t l y modified surface tension expression a l s o derived by Beerbower. (9) (See e q u a t i o n 21) To d e t e r m i n e t h e p o l a r i t y (6p) a n d hydrogen b o n d i n g v a l u e Hansen's equation c a n be used: 6f; + 6

2

= 6

2

(6ft),

- 6^

(21)

The o r i g i n a l s u r f a c e t e n s i o n e q u a t i o n w a s : Y = (.0715) x ( V V 3 ) S

x

($2

+

#

6

3

2

x

{ 6

2

+

6

2

} }

( 2

a n d was u s e d s u c c e s s f u l l y f o r m e l t e d m e t a l s a n d f u s e d s a l t s . modified expression used f o r s a l t water s o l u t i o n s i s : Y = (.0715) x ( V

1 / 3 S

)

2)

The

x (6^ + .678 x (6^ + 6^) )

(23)

An example o f t h e c a l c u l a t i o n s u s i n g t h e e x p r e s s i o n s above i s seen i n F i g u r e 2 .

A s e t o f s u r f a c e t e n s i o n s h a s been c o r r e l a t e d a n d a n accompanying s e t o f C . E . D . p a r a m e t e r s f o r KOH, K C 1 , L i C L , N a C l , N a B r , and N a N 0 were e v a l u a t e d i n 20 d i f f e r e n t c o n c e n t r a t i o n s w i t h a n o v e r a l l e r r o r o f l e s s t h a n 3.0%. The e r r o r was t h e same u s i n g d i v a l e n t s a l t s s u c h a s B a C l , H S 0 4 , MgSC>4 a n d N a 0 0 . 3

2

2

2

3

See T a b l e I I f o r r e s u l t s o f s u r f a c e t e n s i o n c a l c u l a t i o n s reported r e s u l t s .

versus

Conclusion A p p l i c a t i o n o f t h e s e a d d i t i o n a l c a l c u l a t i o n methods, t o d e t e r m i n e C . E . D . parameters and d a t a p o i n t s , a l l o w s t h e f o r m u l a t i o n d i e m i s t t o c o n s i d e r the i n t e r a c t i o n o f emulsions, d i s p e r s i o n s , s o l u t i o n s and c o l l o i d s a s a more u n i f i e d s y s t e m . These C . E . D . p a r a m e t e r s have been s u c c e s s f u l l y u s e d i n s u r f a c t a n t s e l e c t i o n s a n d s o l u b i l i t y e v a l u a t i o n s t o p r e d i c t i n t e r a c t i o n s a n d s o l u b i l i t y . The D% f a c t o r was f o u n d t o b e m i n i m a l i n i t s c o n t r i b u t i o n and c a n b e dropped without a l o s s i n accuracy. That leaves the equation dimensionally c o r r e c t as w e l l as accurate.


160


KCH

. 5 M , 2.75% A I , 1.022 S p . G r . , no = 1-3384, A T f = 1.724

n/n = 1 . 0 5 1 , AP =

1 5 . 0 , y @ 2.73%

0

= 73.95

P = 760-15 = 7 4 5 . 0 f r o m steam t a b l e s @ P = ( 7 4 3 . 8 5 , 7 4 9 . 2 ) ; _.014232806 _ - ^ = .000020201 » T = (99.4, 99.6) ATT

n


7

4> =

(1.051 - 1 . 0 0 ) / 2 . 5

M =

(1.724) x (1000 - 2 7 . 5 ) / ( 1 . 8 6 ) x (1000) = .90139

MV V

=

=

s

=

(1/.90139) x (19.96086)

=

=

.01633

%

= 5 4 . 2 8 3 4 / ( 5 4 . 2 8 3 4 + .9039)

=

.9837

AH

= 17.7257 + .3325

=

AH^ = ( 7 . 6

2

+ 7.8

2

= 2

+ 2 0 . 7 ) x 18.018 + 1.986 x (298.15) =

(4.7406) x (18.0

2.1259 = 10449.59352

7) = 10449.59352 -

85.74181

= 10363.85171 A H ^ B - 10363.85171 - 592.1259 = 9771.72581 6 6 6

2

= 9 7 7 1 . 7 2 5 8 1 / L 8 . 0 1 8 = 542.3313 2

= 4 . 2 2 ( n - 1) + 4 . 3 2 = 4 . 2 2 x ( 1 . 3 3 8 4 - 1) + 4 . 3 2 = 4 . 2 2 (.7913) + 4 . 3 2 = 7.6593 2

D

P

+

6

H

=

542.3313 - 58.6656

Y = (.0715) x ( 1 5 . 0 8 6 7 ) V 3

x

=

483.6657

(58.6656 + .678 x (483.6657) ) =

.0715 x (2.6236) x (386.59096) = 7 2 . 5 2

% Error

=

0

4.7406

(547.09)x(18.018)+592.1259=9857.46762+5 AHss= 10449.59352 -

1

18.0582

= 709.2816 - 704.5410

S

4

54.2834

= . 9 0 1 3 9 / ( 5 4 . 2 8 3 4 + .90139)

s

5

= 20.3593

%

s

R i l l f t

19.96086

N = (1000/1.022 - 1 9 . 9 6 0 8 6 ) A 8 . 0 2

V

4

.0204

= (1000/1.002) x (.0204)

S

0

100 -

(100) x ( 7 2 . 5 2 ) / 7 3 . 9 5

=

1.94%

Figure 2. Calculation of Surface Tensions.


14.

MEUSBURGER


161

Table II. Comparison of Calculated and Observed Surface Tensions


Salt

Molar

Calculated Surface Tension

Observed Surface Tension

H2S04

0.50 1.00 2.00

73.7 74.4 75.5

72.3 72.6 73.4

HC104

0.61 1.01 3.15 7.87

72.8 72.4 70.1 79.1

70.3 70.3 68.7 69.2

KQH

0.50 1.00

73.1 73.3

74.0 74.9

KC1

0.50 1.00 2.00

72.5 72.1 71.5

73.5 74.2 75.6

LiCl

0.50 1.00 2.00 3.00

73.4 73.8 74.3 74.9

72.9 73.6 75.4 77.2

NaCl

0.50 1.00 2.00 3.00 4.00

73.1 73.3 73.7 74.5 75.5

73.8 74.4 76.1 77.7 80.0

BaCl2

0.50

73.7

73.5

Mgci

0.50

74.6

74.0

NaBR

0.50 1.00

72.8 73.3

73.5 74.1

MgS04

0.50 1.00

77.2 85.1

73.8 76.8

Na2C03

0.50

75.6

74.1

NaN0

0.50 1.00 2.00 3.00

72.8 72.9 73.5 74.7

73.8 74.0 75.3 76.7

2

3


162


Literature Cited 1. 2. 3. 4. 5.


6. 7. 8. 9.

Hildebrand, J. and Soott R., "Solubility of Non-Electrolytes", Third Edition, Reinhold Publishing Corp., 1968, pp. 682-708. Hansen, C.M., Journal of Paint Technology, 1967, p. 39, #505, pp. 105-117 and #411, p. 500. Beerbower, A. and Nixon, M.W., "McCutcheon's Emulsifiers and Detergents", 1971. Scher, H . , "Advances in Pesticide Formulation Technology", American Chemical Society, 1984, p. 121-137. Barton, A., CRC Handbook of Solubilities and Other Cohesion Parameters, CRC Press, Inc., 1983, p. 94-109. Torquato, S., and Stell, G . , Ind. Eng. Chem. Fundam., 1982, 21;202. Weast, R., et.al., "Handbook of Chemistry and Physics 53rd Edition", CRC Press, Inc., 1972, D-148-D-149. Adamson, A., "A Textbook of Physical Chemistry", Academic Press, Inc., 1973, p. 263-265. Reprinted from Encyclopedia of Chemical Technology, "Solubility Parameters", Supplement Volume, Second Edition, John Wiley and Sons, Inc., 1972. f

RECEIVED March 18, 1988


Pesticide Formulations - ACS Publications - American Chemical Society

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