Styrenation of Esters of BisphenolEpichlorohydrin Condensates J. W. R/ICNABB1 AND HENRY F. PAYNE Polytechnic Institute of Brooklyn, Brooklyn, N. Y .
T
HE styrenation of fatty acids, oils, and alkyds for surface
reported in this paper indicate the direction for further work with these materials.
coatings has received a great deal of attention in recent years and numerous products of this type have been made available commercially. These products show the inherent advantages of polystyrene, such as fast drying, hardness of film, and improved v-ater and chemical resistance. They also show the inherent disadvantages, such as sensitivity to aromatic hydrocarbons, lack of mar resistance, and tendency toward thermoplasticity. Two basic methods of preparation have been developed for the combination of styrene with oils and oil derivatives: The solvent method (6, 9, IO, 12, 19-22) and the mass method ( I , 5-5, 8 , 1 1 , 14, 15, 16, $3). The Dow process (4)utilized a-methylstyrene as a modifier for the mass method. The present paper shows the procedures used in 12 selected experiments and results obtained from the styrenation of the esters of Epon resins. These resins are condensation products of bisphenol and epichlorohydrin; their structure has been described ( 1 7 ) and is pictured in Figure 1.
EXPERIMENTAL
MATERIALS USED. The materials used and the companies they were obtained from are listed in the following table: Epon 1001 Epon 1004 Monomeric styrene LM-100 a-hIethylstyrene Dehydrated castor oil f a t t y acid (Supra Isoline fatty acids) Solvesso 150 Benzoyl peroxide Di-tert-butyl peroxide
1
Present address, Kienle & Co., 33 Nassau Ave., Brooklyn 22, N. Y .
Woburn Chemical Co. Standard Oil Co. Lucidol Division, Novailrl-Aeene Corp. Shell Chemical Co.
ESTERIFICATION.The present investigation consisted of the styrenation of the dehydrated castor oil fatty acid esters of Epon 1001 and 1004. Equivalent quantities of the resin and dehydrated castor oil fatty acids were esterified by conventional terhniques. This consisted of charging the reactants into a 4-necked, &liter flask equipped vvith thermometer, inert gas inlet, mechanical agitator, and a water-cooled reflux condenser in combination with a Stark and Dean unit. The charge was heated uith an electric mantle with a variable rheostat control to 245' C. and held for constant acid number. The physical constants of the dehydrated castor oil esters of Epon 1001 and 1004 are given in Table I.
Figure 1. Typical Structure of Epon Resin
The preparation of these resinous polyols and their fatty acid esters is described by Greenlee (7'). Long ( I S ) discussed Greenlee's work in considerable detail, and Bradley ( 2 ) indicated the potential commercial possibilities of these new synthetic products. Tess and May ( 1 8 ) investigated the tall oil esters of the Epon resins. From a study of the structure it will be seen that the terminal groups are epoxy groups and that secondary hydroxyl groups occur within the polymer chain. Upon hydrolysis of the epoxy groups there would be only two primary hydroxyl groups on each molecule for esterification. This may account for the difficulty encountered in attempting to obtain low acid numbers when utilizing equivalent quantities of reactants for esterification. However, it has been reported that the Epon esters do not show the poor water and alkali resistance obtained with oils and alkyds when an excess of poly01 is used. The fatty acid esters of these resins undoubtedly contain a considerable number of secondary hydroxyl groups within the chain which have not been esterified. The polar nature of these groups apparently is responsible for the excellent adhesion noted for these esters. The Epon fatty acid esters also show excellent chemical resistance. This may be explained by the ether linkages between monomeric units which are more resistant to alkali and chemicals than the ester linkages found in alkyd- and maleic-type resins. It will be also noted that the presence of the aliphatic units derived from epichlorohydrin adjacent to each bisphenol unit gives rise to unusually good flexibility not normally associated with phenol-derived resins. HOVever, it was considered possible that styrenation of the fatty acid esters of the Epon resins might still further improve these materials with an added advantage of reducing the cost. The results
Shell Chemical Co. Shell Chemical Co. Monsanto Chemical Co. Don- Chemical Co.
TABLE I.
CHARACTERISTICS O F DEHYDRATED C.4SToR OIL ESTERSO F EPOKRESIKS
PHYSICAL
Ester of Epon 1004 100% Solid Rasia Acid number Refractive index,
ng
30 1 5250
75% Solids i n Solvesso 150 Viscosity, Gardner-Holdt 23-24 Viscosity, poises (approx.) 55 Color, Gardner 1933 stds. 5 5
Ester of Epon 1001 35.1 1.5146
w
11 7.5
COPOLYMERIZATION. All copolymerizations were carried out in a 4-necked, 2-liter resin reaction flask heated by an electric mantle with a variable resistance control. Through the central neck a stainless steel stirrer fitted with a glass seal nyap rotated by a variable speed electric motor. A thermometer was fitted into one of the side necks and a separatory funnel and a watercooled reflux condenser were fitted into each of the other necks. The solvent method was used in this investigation. I n those experiments in which a-methylstyrene was used as a modifier, the ratio was 35% ~~-methylstyrene-65%styrene. In all cases, the reaction temperature was 145" C., and the catalyst concentration was 3% by weight of total styrenes. Benzoyl peroxide and di-tert-butyl peroxide were used as catalysts. Solvesso 150 was used as the solvent and, except for one experiment (number 7j, the styrene with catalyst was added portionwise to the heated ester solution over a 3-hour period of time. The course of the reaction was followed by nonvolatile determinations on samples taken a t intervals. From the known input and the nonvolatile determinations the per cent styrene in the product was calculated. The relationship between the
2394
October 1952
INDUSTRIAL AND ENGINEERING CHEMISTRY
time of reaction and the per cent styrene in the product was plotted. I n all cases the initial time of reactioq was taken immediately after the addition of styrene was complete. The viscosity of the reaction product was also followed during each experiment.
TABLE11. W-EIGHT Dehydrated Castor Oil F a t t y Aoid Ester of
Expt. Epon 1004,
.
.
BATCHESFOR STYRENATION OF DEHYDRATED CASTOROIL ESTERS OF EPON 1001 AND 1004
Dehydrated Castor Oil F a t t y Acid Ester of Epon 1001, Grams
No. Grams STYRENATION OF DEHYDRATED CASTOR 1 250.0 OIL FATTY ACID ESTER OF EPON 1004. 2 250.0 Table I1 indicates the quantities of ma3 250.0 4 250.0 terials used in each experiment. I n view 5 250.0 6 250.0 of the high viscosity of the dehydrated 7 250.0 castor oil fatty acid ester of Epon 1004 8 9 two experiments were conducted to de10 .... 11 termine if a modifier such as a-methyl12 .... styrene was necessary in order t o control the copolymerization reaction. Experiment 1, using straight styrene, gelled in 11 hours after addition of the styrene-catalyst mixture was complete. Experiment 2, using styrene-a-methylstyrene mixture, was completed without difficulties. The data for the rates of reaction are plotted in Figure 2. It was apparent that further work with the ester of Epon 1004 would necessitate the use of amethylstyrene as a modifier t o inhibit gelation. f
OF
.
2395
....
.... ....
....
250,'O 250.0 200.0 200.0 200.0
Solvesso Grams
150,
Styrene, Grams
500.0 500.0 500.0 500.0 500.0 500.0 500.0 500.0 500.0 400.0 400.0 100.0
62.5 40.63 81.25 130.0 130.0 130.0 130.0 62.5 156.3 200.0 130.0 130.0
n-Methylstyrene. Grams
Benzoyl Peroxide, Grams
....
1.88 1.88 3.75
21.87 43.75
70.0
70.0 70.0 70.0
....
....
6.0
....
.... ....
.... 7 70.0
Di-totbutyl Peroxide, Grams
....
1.88 4.69 6.0 6.0 6.0
Ratio of Styrenes to 100 Parts of Ester 25 25 50 80 80 80 80 25 62.5 100 100 100
50
40 t-
o 3
n
2
30
a
f
B 2
20
L1 LL
>
f;;
IO
3 0
Figure 3.
4
8 I2 T I M E I N HOURS
16
20
24
Effect of Ratio of Total Styrenes to Epon Ester on Rate of Reaction
Rate of reaction w t h 100 parts of ester to 25 parts of mixed styrenes (experiment 1 ,100 parts of ester and 50 parts of mixed styrenes (experiment 21, and 100 arts of ester and 80 parts of mixed styrenes gxperiment 4)
T I M E IN HOURS Figure 2. Effect of Modifier on R a t e of Reaction 100 parts of ester to 25 parts of styrene Experiment l , l O O % styrene Experiment 2, 65% s t y r e n e 4 5 9% a-methylstyrene
. I n experiments 2, 3, and 4, the ratio of total styrenes t o Epon ester was increased progressively in order t o determine its effect on the control of the reaction. Satisfactorily clear products were obtained in each of these experiments, and the data for the rates of reaction are plotted in Figure 3. The data show that under the conditions used an excess of the mixed styrenes is required over that amount which is combined in the product. In experiments 4 , 5 , and 6, a comparison was made of the results obtained without catalyst and with benzoyl peroxide and di-tertbutyl peroxide as catalysts for the copolymerization reaction. The reaction products were clear when either catalyst was used,
but the product made without catalyst had a slight haze. From Figure 4 it is apparent that the use of di-tert-butyl peroxide as the catalyst resulted in a considerably faster and more efficient reaction than when benzoyl peroxide was used. The color of the product using di-tert-butyl peroxide as the catalyst was much better than when benzoyl peroxide was used. As a result di-tertbutyl peroxide was used as the catalyst in all subsequent experiments. Experiment 7 was conducted to determine the feasibility of producing satisfactory copolymerization when the entire charge was placed in the reaction vessel, instead of using the portionwise technique. The product obtained was hazy, indicating incompatibility. It was apparent that addition of the styrenes-catalyst mixture portionwise to the heated Epon ester solution was necessary to obtain a homogeneous product. The data for the rates of reaction of experiments 5 and 7 are plotted in Figure 5 . The rates of reaction are practically identical, probably because the time for the portionwise reaction was not started until all of the styrenes had been added. The physical properties of the styrenated products of the dehydrated castor oil fatty acid ester of Epon 1004 are listed in Table 111. STYRENATION OF THE DEEYDRATED CASTQROIL FATTY ACID ESTEROF EPON1001. The ester of Epon 1001 waa considerably less viscous than the ester of Epon 1004. Therefore, experiments 8 and 9 were conducted using straight styrene in the ratio of 100
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INDUSTRIAL AND ENGINEERING CHEMISTRY
VOl. 44, No. 10
TABLE111. PHYSICAL PROPERTIES OF STYRENATED DEHYDRATED CASTOROILESTERS OF EPOX 1004 A N D EPON1001
0
Ratio of Styrenes t o 100 Parts of Ester
Reaction Styrenes, % Time Catalystsa Hour: Reacted In product 15.1 2 BP 24 71.0 25 24 73.6 BP 26.9 50 3 24 40.2 84.0 BP 4 80 42.2 DTBP 18 91.4 80 5 18 30.1 6 53.7 None 80 19 86.7 40.9 DTBP 7 80 18.5 19 90.8 DTBP 8 25 11 96.2 62.5 37.5 DTBP 9 46.2 17 85.6 DTBP 11 100 Catalysts: BP benzoyl peroxide; D T B P = di-twt-butyl peroxide.
Expt. No.
Viscosity GardnerHoldt Poises
Nonvolatile. %
I Q-R
36.2 39.1 42.9 44.6 37.6 44.6 37.8 44.1 46.4
v-W
x-Y H
... 1'-w
Col01 Gardnei
1933 Std5
'3.5
2.25 4.50 9.5 15.0 2.0
9.5 9.5 7.0 4.5
1.1 9 .5 2.9
7.3 6.5 9.5
...
D-E
K-L
Acid No., Nonvolatile
Appearance of Product Clear Clear Clear Clear Hazy Hazy Clear Clear Clear
25.7 21.7 18.5 17.6 18.5 17.0 28.6 22.4 19.0
5.5
E
50
I
1
I
I
1
I
I
I
I
e-
s T I M E IN HOURS Figure 5. Effect of Process Variation on Rate of Reaction
Figure 4,. Effect of Catalyst on Rate of Reaction 100 parts of ester t o 80 parts of mixed styrenea Experiment 4, without catalyst Experiment 5, with benzoyl peroxide Experiment 6, with di-tert-butyl peroxide
100 parts of esLer t o 80 parts of mixed styrenes In evperiment 5 styrenes were added portionwise and i n exposim e n t 7, i n situ process was used
g 20 W
a
>.
L 10
I
I
Experiment 8, 100 parts of ester to 25 parts of styrene Experiment 9, 100 parts of ester to 62 parts of styrene Experiment 11, 100 parts of ester t o 100 parts of mixed styrenes
parts of ester to 25 and 62.5 parts of styrene, respectively. The products of both of these experiments were clear and homogeneous and no gelation difficulties were encountered. It is apparent from a comparison of experiments 1 and 8 that less difficulty from the standpoint of gelation can be expected with the styrenation of the dehydrated castor oil fatty acid ester of Epon 1001 because of its
lower molecular weight indicated by lower viscosity. The data for the rates of reaction of experiments 8 and 9 are plotted in Figure 6. The data are similar to those obtained with the ester of Epon 1004 in experiments 2, 3, and 4 (Figure 3) in that they indicate an excess of styrene must be used over that which is combined in the product. However, the required excess styrene is somewhat less with the ester of Epon 1001. It will be realized that the excess may possibly be lowered still further by changing the reaction conditions. Although the ester of Epon 1001 showed no gelation tondcncy \\-hen styrenated with the ratio of styrene shown above it gelled in 30 minutes when the styrene ratio was increased to 100 parts of ester-100 parts of styrene (see experinieni 10). However, clr:w products T\-ere obtained in experiment 11 using the styrene-emethylstyrene mixture. It is apparent that a-methyl styrene is necessary under the experimental conditions when relatively high percentages of styrene are desired in the product. The data for cxperirnent 11 are plotted in Figure 6 so that direct comparison may be made Lvith those obtained in experiments 8 and 9. A s may be expected from t,he fairly high molecular weights of the dehydrated castor oil fatty acid esters of Epon 1001 and 1004, a relatively high dilution with solvent is necessary to obtain gelfree products. No attempt was made to determine the effect of various solvents on the rate of the reaction or products obtained. However, experiment 12, using a low dilution with Solvcsso 150, gelled in 30 minutes, indicating that high dilution is necessary with this solvent. A high ratio of mixed styrenes to Epon cster was used in experiment 12. The physical properties of the styrenated products of the dehydrated castor oil fatty acid ester of Epon 1001 are listed in Table 111.
October 1952
INDUSTRIAL AND ENGINEERING CHEMISTRY
2397
LITERATURE CITED
SUMMARY
This work has shown that homogeneous products may be obtained from the styrenation of the dehydrated castor oil fatty acid esters of Epon resins 1001 and 1004. The solvent method was used, but it is necessary t o use approximately equal parts of solvent and total charge t o prevent gelation when the solvent is Solvesso 150. The high viscosity of the ester of Epon 1004 necessitates the use of a mixture of styrene and a-methylstyrene for control of the reaction. With the ester of Epon 1001 straight styrene may be used when low percentages of combined styrene are desired. However, the mixture of styrene and a-methylstyrene is necessary when high percentages of styrene are desired in the final product. Using the technique of adding the styrene-catalyst mixture portionwise t o the heated ester solution, no difficulties were encountered in obtaining homogeneous styrenated products throughout this investigation. When the styrenes were placed in the reactor a t the start of the reaction the products were incompatible. As may be expected from results obtained with other materials, a catalyst is necessary t o produce homogeneous styrenated Epon esters. A comparison of benzoyl peroxide and di-tert-butyl peroxide showed the latter t o be superior in respect t o the efficiency of the reaction under the conditions used. The products o b tained with di-tert-butyl peroxide were decidedly superior in color t o those obtained when benzoyl peroxide was used. Preliminary evaluations of these copolymers indicate improved resistance to water and alkali, while maintaining the excellent adhesion and flexibility characteristics of the Epon resin esters.
Bhow, N., and Payne, H. F., IND. ENG.CHEM., 42,700 (1950). Bradley, T. F., Oficial Digest Federation Paint (e: Varnish Praduction Clubs, No. 310 (1950). Detroit Paint and Varnish Club, Ibid. No. 286, (1948). Dow Chemical Co.,“Styrenated Drying Oils,” Midland, Mich., 1948. Dunlap, L. H., U. S. Patent 2,382,213(1945). Flint and Rothrock, Ibid., 2,225,534(1940). Greenlee, S. O.,Ibid., 2,456,408(1948). Griess, G. A., and Teot, A. S., Ibid., 2,468,748(1949). Hewitt, D. H.,and Armitage, D., J . Oil & Colour Chemists’ ASSOC., 29,109-128 (1946). Hewitt, D. H., and Wakeford L. E., U. S. Patent 2,392,710(1940). Hoogsteen, H.M.,Young, A. E., and Smith, M. K., IND.ENQ. CHEM.,42,1587 (1950). Lawson, W. E., and Sandborn, U. S. Patent, 1,975,959(1934). Long, J. S.,J . Oil & Colour Chemists’ Assoc., 32,No.350 (1949). Petersen, N. R.,Oficial Digest Federation Paint & Varnish Production Clubs, No. 283 (1948). Powers, P. O., IND. ENG.CHEM.,42,2096 (1950). Sohroeder, A. M.,and Terrill, R. L., J . Am. Oil Chemists’ Sac., 26,153 (1949). Shell Chemical Co., Tech. Bull. SC:50-40 (1950). Tess, R. E.,and M a y , C. A,, Oficial Digest Federation Paint & Varnish Production Clubs, No.311 (1950). Wakeford, L. E., and Hewitt, D. H., Brit. Patent 573,809 (1945). Wakeford, L. E.,Hewitt, D. H., and Armitage, F., Ibid., 573, 835 (1945). Ibid.. 580.912 (1946). Wakeford, L. E., Hewitt, D. H., and Davidson, R. R., Ibid., 580,913 (1945). Young, A. E., Oficial Digest Federation Paint & v a r n i s h Production Clubs, No.296 (1949). R E C ~ I V Efor D review January 22, 1952. ACCEPTED June 3, 1952. Presented before the Division of Paint, Varnish, and Plastics Chemistry at the 121st Meeting of the AMERICAN CHEMICAL SOCI~TY Milwaukee, , Wia., March 30-April 3. 1962.
Effect of Temperature on Azeotropy in 1,LDif luoroethane and Dichlorodifluoromethane W. A. PENNINGTON Carrier Corp., Syracuse, N .
I
N RECENT years use has been made of a solution of 1,l-
difluoroethane (Genetron 100) and dichlorodifluoromethane (Freon 12) as a refrigerant, the specified composition being that of the azeotrope a t 0” C. (The new azeotropic refrigerant is Carrene-7.) It has been employed primarily in air-conditioning equipment where the evaporator temperature is usually held between 5 ” and 6 ” C. For azeotropic systems in general, the azeotropic composition changes with temperature, the solution becoming richer with respect to the substance having the higher molar latent heat as the temperature increases. Since this nen refrigerant may be used where the evaporator temperature is low, information is needed concerning the change of azeotropic composition with temperature. GENERAL EFFECT OF TEMPERATURE ON AZEOTROPY
Even though there are a great many data in the literature on azeotropic systems a t some single pressure, there are not many to be found with changing pressures. Since there is a boiling
Y,
temperature for each pressure and composition, this means there is also a dearth of data on azeotropic systems a t varying temperatures. In refrigeration, attention should be focused on the temperature rather than the pressure. Swietoslawski (7) gives a graphical representation of the effect of change of temperature on a system characterized as the maximum-pressure type of azeotrope. Recently, Skolnik (6) discussed the effect of pressure on azeotropy. He arrived a t the conclusion that two sets of accurately determined data-pressure, boiling point, and composition-data completely define an azeotropic system. He gives the equation, log z = a
+ bT
(1)
where 2 is the mole per cent of one substance and T is degrees Kelvin. Obviously, this relation is not compatible with that shown graphically by Swietoslawski because z could not be zero at any real value of T. For this reason, it seems advisable t o search for another type of equation which would be more suitable, particularly for extrapolation purposes. Skolnik showed,
