August
INDUSTRIAL AND ENGINEERING CHEMISTRY
1950
LITERATURE CITED
( 1 ) Am. SOC.for Testing Materials, Test Method D 39547T. (2) Andrews, R. D., Tobolsky, A. Y., and Hanson, E. E., J. Applied Phys., 17,352 (1946); Rubber Chem. and Technol., 19, 1099
(1946). (3) Beatty, J. R., and Juve, A. E., India Rubber World, 121, 537 (1950). (4) Bekkedahl, N. J., J . Research S a t l . Bur. Standards, 13, 411 (1934); Rubber Chem. and Technol., 8, 5 (1935). ( 5 ) Bekkedahl, N.. and Matheson, H., J. Research Natl. Bur. Standurds, 15, 503 (1935); Rubber Chem. and Technol., 9, 264 (1936). (6) Bekkedahl, N., and Wood, L. A,, IND. ENG.CHEM.,33, 381 (1941); Rubber Chem. and Technol., 14,347 (1941). (7) Beu, K. E., Reynolds, W. B., Fryling, C. F., and McMurry, H. L., J . Polymer Sci., 3,465 (1948); Rubber Chem. and Technol., 22, 356 (1949). (8) E. I. du Pont de Nemours & Go.. Inc., publication BL-218 (Aug. 8, 1946). (9) Forman, D. B., IND. ENG.CHEM.,36, 738 (1944); Rubber Chem. and Technol., 18, 149 (1945).
158P
(10) Gehman, S. D., Jones, P. J., U’ilkinson, C. S., Jr., and Woodford, D. E., IND.ENG.CHEM.,42,475 (1950). (11) Gehman, S. D., Woodford, D. E., and Wilkinaon, C. S., Ihid., 39, 1108 (1947); Rubber Chem. and Technol., 21, 94 (1948). (12) iMorris, R. E., Hollister, J. W., and Mallard, P. A., India Rubber World, 112, 455 (1945); Rubber Chem. and Technol., 19, 151 (1 946). (13) Rands, R. D., Jr., Ferguson, W. J., and Prather, J. L., J . Research Natl. Bur. Standards, 33,63 (1944). (14) United States Military Specification MIL-R-900(SHIPS) (Sept. 1, 1949). (15) Wiley, R. H., and Brauer, G. M., J . Polymer Sci., 3,704 (1948); Rubber Chem. and Technol., 22, 402 (1949). (16) Wilkinson, C. S., Jr., and Gehman, S. D., Goodyear Tire & Rubber Co., private communication., (17) Wood, L. A., National Bureau of Standards, private communi-
cation. (18) Wood, L. A., Bekkedahl, N., and Roth, F. L., IND. ENG.CHEX., 34,1291 (1942); Rubber Chem. and Technol., 16,244 (1943). RECEIVEDDecember 15, 1949. The opinions or assertations in this paper are those of the authors and are not to be construed as official or reflecting the v i e w of t h e Navy Department or t h e Naval Service a t large.
Stvrenation of Dehvdrated Castor Oil J
J
-
H. M. HOOGSTEEN AND A. E. YOUNG The Dow Chemical Company, Midland, Mich.
M. K. SMITH The Baker Castor oil Company, Bayonne, N. J . I n order to evaluate more extensively the relationship between the properties of dehydrated castor oil and of the styrenated product based on the oil, a series of oils was prepared under different conditions and made to react with styrene using both mass and solvent methods of polymerization. The properties of 23 oil samples are listed in two tables and the interrelationships shown in three graphs. The properties of the styrenation products
c
OMMERCIAL experience has indicated that valuable paint vehicles may be prepared by the styrenation of dehydrated castor oil. This same experience has shown also that all dehydrated castor oils do not yield products of equal quality upon styrenation. Hewitt and Armitage ( 3 )discussed briefly the effect of varying the type of dehydrated castor oil used in the styrenation reaction. They found that reduction in diene value or increase in hydroxyl value gives rise t o extended reaction time and may cause opalescence in varnish or film. They also found that bodied dehydrated castor oils yielded styrenated products of improved water resistance as compared with styrenated unbodied oils. The work of Griess and Teot (2)also indicated that the properties of dehydrated castor oil which influence the reactivity towards styrene varied depending upon the source and history of the oil. Dehydrated castor oil is obtained by removing the elements of water from castor oil. Although castor oil is the glyceryl ester of a mixture of fatty acids, approximately 85% of this mixture is ricinoleic acid. This particular fatty acid contains a secondary alcohol group removed by one carbon atom from a double bond. 4CH,(CH,)~C€I,-CHOH-CHz-CII=CH( CH,( CH,LCFT?-CH=CH--CH=CH(
are reported in two tables and the rate curve is plotted for three of the styrenation reactions. A relationship is found to exist between the viscosity and degree of dehydration of the castor oil and the homogeneity and film properties of the styrenated product. The most desirable products are obtained by styrenating castor oil that has been dehydrated to a minimum hydroxyl content and then has been bodied to a viscosity approaching 15 poises.
Dehydration consists in removing the hydroxyl group together with a hydrogen from one of the two adjacent carbon atoms and, therefore, introduces a new double bond in one of two posit,ions Generally, in commercial practice about 25% of the linoleic acid formed is conjugated and about 75% is the nonconjugated isomer. (See Equation 1.) The exact ratio of these two isomers in the product will be a function of the reaction conditions employed. Other properties of the dehydrated oil must also be considered, such as viscosity, color, and hydroxyl value. The product can polymerize, resulting in an increase in viscosity and a reduction in total unsaturation. Also, interchange is possible between the hydroxyl and ester groups. The reaction conditions will also determine the extent of these side reactions. In order t o evaluate more extensively the relationship between the properties of dehydrated castor oil and the properties of the styrenated products based on the oil, a series of oils was prepared under different conditions and made to react with styrene using both mass and solvent method of polymerization.
- HzO CHg)?COORcatalyst heat +
CH2)rCOOR
f
+ 3 CH,(CH,)rCH=CH-CH,-CH=CH(C~,)7~~~~ (1)
TABLE I.
PROPERTIES O F O I L SA\IPLES
T-\KEIG DURIYG
xORMIL
DEHYDRlTION
7
Property
1
Color Viscosity a t 25' C. s p , gr.,,250C . / 2 j 0 C. Refractive index a t 25' C.
3 t O f 0.9.54
Zp%!\;alue Wijs iodine value Diene by ultraviolet as linoleic acid OH b y infrared as % ' castor oil a
2 it
0.949
3
4
5
6
3 M 0.936
4 f
$+
3
0.942
0.939
0.934
I
AND
Sample No. 7 8 3 3 0 P 0.938 0.937
SVBSEQUl3YT BODYIKG OF ~
9 4+
~
IO
11
U t
X+
3
Ti-
___..
13
12
3 Y-
3
0.9420
0.9389
CASTOR O I L
~~~~
0.9401
-
3
$!&85
0.9499
1.4858 1.4861 1.4833 1 . 4 8 4 1 1.4816 1.4852 1.4828 1,4830 1.4812 1.4821 1.4793 1.4804 1.4785 2.25 1.81 187 1.48 3.66 3.48 3.35 3.19 4.32 2.63 1.40 1.70 2.25 188.6 189.4 188.5 188.2 188.7 188.7 188.7 188.3 188.2 189.9 186.5 188.5 185.1 133.5 132.7 129.8 125.9 125.5 122.8 134.8 135.3 135.2 130 6 134.4 106.7 116 7 9.8
13.8
90
57
25 33.5
23.3
22.4
20.7
22.4
24.1
20.8
27
20
18
17
16
18
20.5
19.5
19.0
18.0
15.8
17.5
17.8
17.0
FFA, free fatty acid.
TABLE11.
BODYING OF
PROPERTIES O F OIL SAMPLES TAKE?DURING series .I,Sample No. 14a 15 16 17
7
7
Property
Color Viscosity at 25' C . Sp. gr., 2 j 0 C . / 2 5 O C . Refractive index a t 25' C . ?7 FFA &on. value Iodine value Diene by ultraviolet as linoleic acid 0 by infrared as % castor oil
2 (I
VoI. 42, No. 8
INDUSTRIAL AND ENGINEERING CHEMISTRY
1588
4+
L-
0.9399 1.4798 2.80 186.0 120.1
5+
11 0.936 1.4828 1.98
190,: 129.2
18 5+
5f
0 0,937 1,4830 1.98 190.9 128.5
R+
+; ,
0,939 1.4831 2.03 191.3 126.4
0.938 1.4831 1.98 190.3 127.3
-
P h R T I l L L Y DCHYDR.4TED C4bI'OR O I L 5 Series B, Sample To.------19a 20 21 22
6+ I+ 9 3 1.4804
o
2.52
188.0 128.3
6+ L+ ~ n.936 1.4813 1.34 188.3 124.0
6+
+ oM937
1.4819 1.63 189.2 123.5
;+
0.989 1.1823 2.13 189.6 122.8
23 6' R 0 !K39
-.
1,4828
2.08 189.1 122.9
16
21
20.4
21.8
18.7
18.7
19.2
18.7
18.2
18.3
62
30
29
25.5
24
45
34
36
30
19
Samples 14 and 19 represent the two partly dehydrated oils before heat-bodying
EXPERIJIENTA L
The properties of the oils are listed in Tables I ant1 I1 and the interrelationship of these properties is shown in Figures 1 and 2 . In the preparation of a first group of oils, castor oil was subjected t o dehydrating conditions and samples 1 through 4, having hydroxyl content as shown in Table I, were removed a t intervals (Figure 1). The product, sample 4, was heated under oil polj-merizing conditions and further products, represented by samples 5 through 13, were produced. The continued reduction in hydroxyl value during the polymerization step s h o m that dehydration may have continued to occur during this step. There is also the possibilit,y that the reduction is due to interesterification accompanied by volatilization of glycerol. Viscosity decreased during the dehydration step and increased during t,he polymerization st,ep. Iodine and diene values increased with dehydration and slowly decreased with polymerization. The second and third groups of oils (Table 11) were prepared by only partially dehydrating castor oil and polymerizing the resulting partially dehydrated oils. Portions of the oils were removed at intervals to give products of different stages of body. Figure 2 shows the properties of these two groups of oils, com-
pared with the products of normal proressing as illiistrated in Figure 1. The cast,or oil !vas dehydrated under vacuum a t tenipcra,tures of 240' to 250" C. using niirieral acid catalysts. In the case of
IS
21
23
OIL SAMPLE
Figure 1. Properties of Oil Samples Taken during Normal Dehydration and Subsequent Bodying of Castor Oil
Figure 2. Properties of Oil Samples Taken during Bodying of Partially Dehydrated Castor Oil Above. Below.
Series A Series B
August
I N D U S T R I A L A N D E N G I N ~ E R I N GC H E M I S T R Y
1950
the most completely dehydrated oil (sample 4,Table I), it was run to a refractive index of 1.4812 and a Gardner-Holdt viscosity of G-H, this being the minimum viscosity for dehydrated castor oil which is presently being obtained on a commercial scale. The partly dehydrated oils (samples 1, 2, and 3, Table I ) were obtained under the same conditions by using less catalyst and a shorter reaction time. All subsequent bodying was done under reduced pressure a t temperatures of 285' t o 290' C. The analytical constants listed in Tables I and I1 were determined using standard methods with the exception of the methods for diene value and hydroxyl content, respectively. The former measurements were made using a modification of the technique described by Kass ( 4 )and Brice and Swain (1). The hydroxyl content of the oil samples was obtained by infrared analysis. This was performed by using as a standard reference the infrared absorption spectrum of a U.S.P. grade of castor oil, thereby obtaining the hydroxyl content of the various samples in terms of castor oil. The specific sample of castor oil employed was found by infrared analysis to have a hydroxyl concentration of 27.5% as nonyl alcohol. Two techniques were employed for the reaction of styrene with the series of dehydrated castor oils.
1589
E
0
I
I 2
4
I 8
6
I 10
I 12
I
lo
14
16
REACTION TIME IN HOURS
Rate of Styrenation of Oils at Three Viscosities, Series M
Figure 3.
45 to 55 by weight. A solution was prepared ronsisting of 31.5 parts styrene, 13.5 arts a-methylstyrene, and 1.1 parts benzoyl peroxide. One halrof this solution together with 55 parts of oil Cas charged to the reaction flask and heated to 165" C. Then one fourth of the remaining styrene solution was added after t h e first hour. A second one fourth was added after the second hour. This was repeated until all the styrene had been charged. The
MASS METHOD. I n this method a-methylstyrene was used as a modifier for the reaction. The ratio of total styrene t o oil was
TABLE111. PROPERTIES OF PRODUCTS OBTAINEDTHROUGH REACTION OF STYRENE WITH OILS LISTEDIN TABLE:$ I ~ Sample EO.
1M 1s 2M 2s 3M
3s
Properties of Vehicle Residual Viscosity at 50 styrene, % soli2 Clarity
... ... ... ...
1.7
.*.
Clarity
Drying touch, min.
...
A-'i
Good
20
*,. 70
5 70
... ...
.. .. .. ...
I
.
..
..
A A-1
Good Good
Cloudy Good
10 35
4s 5M
0.7 2.6
A t A B
Good Good Good Good Good Good Good Good Good Good Good Good Good Good Good Gel Incomp. Gel Gel
S1. haze Good Good Good Good Good Good Good Good Good Good Good Good Good Good
5 15 8 12
7 hl 7s 8M 89 9M 9s 10M 10s 11M 11s 12M 12s 13M 135
1.7 ,..
1.4
...
0.6 ,..
1.7
... 1.9 ... 2.5 ...
... ...
...
...
.,. ... ...
Cloudy Cloudy Cloudy Cloudy Good
... ...
Flexibility after 30 days
N D 11
Water resistance, appearance after immersion for 72 hr.
Oils Listed in Table I
...
4M
5s 6M 6s
Time to harden, hr.
Properties of Film Hardness after 1 7 30 days days day
4A
B A
C D-E A F-G D
U
N ..I
...
... ...
...
...
.... ..
14 4 13 5 6 7
9 6
18 6
.. .. ..
4.5 6
4 6 4 5 3.5 5.5 4.8 8 3 24 3 5 3.5
... ,.. ... ...
...
TaiGy
... ... ... 4
... ... .10. .. ..
Good
7 Tacky
8 4
14 10
Good Good
13 10 15 10 16 14 18 15 16 16.5 18 16.5 17 21 19
Good Good Good Good Good Good Good Good Good Good Good Good Good Good Good
... ...
...
9 8 10 8 12 8 12 9 12 10 18 11 16 14 13.5
... ...
... ...
11 9 14 8 14 12 14 12 13 14 18 15.5 16 20 18
... ... ...
...
... ... ... .
.
I
..
..
... ... ... ...
.............
Few listers, sl. haze, 5 min recovery SI. haze 10 min recovery Few bli'sters, si. haze, 5 min. recovery SI. haze 15 min. recovery S1. haze', 3 min. recovery Few $1. haze, small3 blisters min. recovery Few small blisters SI. haze, 3 min. recovery Few small blisters No effect Few M a n ys m d l blisters small blisters Film lifted Few sinall blisters Film lifted M a n y small blisters Few small blisters
..............
.............. ..............
.............
Oils Listed in Table I1 14M 14s 15M
1.9
15s 16M
1.6
16s 17M
...
...
.. ..
.. .. ..
Incomp. Incomp. Good
Good
B
S1. incomp. Good
Gddd
9
i:i
g''
SI. incomp. Good
Gddd
10
18M
117
B-C
S1. incomp. Good
Gddd
13
20
18s 19M
2.3
Ai'
SI.incomp. Good
Gddd
24
19s 20M
2.0
Ai'
Incomp. Good
ii ..
Gddi
8
23
20s 21M
2.5
Ai'
Good
17s
21s 22M 22s 23M 238
1.9
...
...
... ...
...
...
., A
.
...
...
1.5
A-'B
2:7
6''
...
...
Incomp.
Incomp. Good SI. inoomp. Good SI. incomp.
10
..
.. I
Gddd Gddd
Gddd
...
.
.. 8
..
..7 12 ..
22
... 16
...
t..
... 10
... '9
'
...
...
I . .
...
...
... ...
9
7
... 7
...
24
7
19
11
... 18
...
... 14
... 24
.. .. .. 12
9
...
... 11
...
13.4
...
14
...
10
... 10
...
... ... 16
...
16
I . .
16
...
16
...
13
...
..............
Gddd
Few blisters, SI. haze, 4 min. recoi-ory
Gddd
Few,blisters, sl. haze, 4 min. recovery
...
..............
..............
Good
Few,blisters, SI. haze, 4 inin. recovery
Gddd
Few,blisters, si. haze, 4 inin. recovery
...
Good
...
..............
..............
Few blisters, SI. haze, 2 hr. recovery
..............
1'4 '
Good
Few blisters, SI. haze, 2 hr. recovery
.
GLod
Few blisters, s hr. recovery
.........
12
15
14
17.5
...
Gddd
Few blisters
17.5
....
Gddd
No effect
... ...
...
14
I
.
.
...
..............
.............. ..... ....
INDUSTRIAL AND E N G I N E E R I N G CHEMISTRY
1590
I!
16
0 O i
I -I--
1
I I I I
HOMOGENEOUS PROOUC S
2 SER ES 0
e
0
4
6
10
e0
40
Vol. 42, No. 8
111. The sample numbers in this table correspond with those in the former two. The letters 31 and S refer to the mass method of reaction and the solvent method, respectively. The mass copolymers were thinned to 50% solids with a solvent mixture of 70 parts mineral spiritsand 30 parts Solvesso No. 2. The solvent copolymers were prepared at i o % solids in xylene and cut to 50% solids by the addition of mineral spirits. GardnerHoldt tubes were employed for the determination of viscosities. The films contained O.O2C/; cobalt and 0.2@"lead naphthenatetype driers as metal based on total solids. Films were cast on glass and Sward hardness measured after aging for 1, 7 , and 30 dam. Flexibility was determined on flowed-out films on tin plate using the conical mandrel The water resistance of the products was evaluated by examining dip-coated glass slides which had been immersed in 4 atel at 25' C. for 7 2 hours. D1SCU SSION
temperature was raised to 210" C. and maintained for an additional 18 hours. Then the temperature was increased to 240" C. for 2 hours during which time volatile material was allowed t o distill. SOLVENT METHOD. The solvent method of styrenation consisted in charging t o the reaction flask 55 parts of oil, 45 parts of styrene, 43 parts of x lene, and 1.1 parts benzoyl peroxide. The reactants were heatex t o refluxing temperature which was in the range 145O to 155' C. and maintained there for 24 hours. The course of the reaction of dehydrated castor oil with the styrene-a-methylstyrene mixtur e in the particular mass method employed is illustrated in Figure 3 . This shows the relationship between the amount of unreacted styrenes in the reaction mass and the time of reaction with three oils of different degrees of body. The amount of unreacted styrenes was defined as the material lost by a l-gram sample after 2 hours in a 100" C. vacuum oven. The degree of body of the oil reacting makes no significant difference in the time necessary for virtual completion of the reaction, However, if the reaction were terminated before the maximum conversion had been reached, Figure 3 indicates that higher yields are obtained with increasing oil viscosity. In addition to the oil, other variables arc operative in determining the reaction rate, Among the more important onw are the kind and quantity of catalyst and the ratio of styrene and a-methylstyrene. Although a-methylstyrene is useful for controlling product homogeneity, it also retards the rate of styrenation. The optimum combination of these two factors is not necessarily illustrated by the concentration of a-methylqtj rene employed in the method described. Properties of the products obtained through the. reaction of styrene with the oils listed in Tablcs I and I1 ale given in Table 20
:
,
I
2
I1
I IO
I IS
J
20
SWARD HARDNESS OF STYRENATED OIL FILM,'M'
SERIES
Figure 5. R e l a t i o n of Original Oil Viscosity to F i l m Hardness of S t y r e n a t e d Oil
Refeiring to Table 111, it will be noted that clear films are obtained through the styrenation of oil samples 5 through 11, when using the solvent method S o n e of the products of the solvent method from oils 14 t o 23, inclusive, were entirely homogeneous. A Tvider range of homogeneous products wa5 obtained through the Darticular mass method that was used. Here clear films were produced through the styrenation of oils 3 to 11, inclusive, and 15 to 23, inclusive. These results are shown diagrammatically in Figure -1. eo 5 ORIGINAL VISCOSITY IO 0
50
0.1
02
0.4
1.0
5.0
IO
SOLUTION VISCOSITY OF STYRENATED OIL, "M" S E R I E S IN POISES
Figure 6.
R e l a t i o n of Original Oil Viscosity
to Viscosity of S t y r e n a t e d Oil
Figure 4 shows plots of hydroxyl contcnt versus viscosity for the three series of oils used in the study. Oils of hydroxyl content less than about 4897, (as castor oil) and of viscosity less than about 16 poises yield useful products by the mass method of styrenation. When using the solvent method, hydroxyl content of the oil should be below about 24% (as cabtor oil), if homogeneous styrenatrd products are to be obtained. From the standpoint of homogeneity of the styrenated product, it can be concluded that dehydrated castor oils manufactured for styrenation purposes should be of as low a residual hydroxyl content as possible. Comparison of the viscosity data on the original oils shown on Figures 1 and 2 with the data on film properties of the styrenated products given on Tables I1 and 111 (14M to 23s) shows four iniportant relationships. Hardness of the end product is greater, the greater the viscosity of the original oil. This relationship is shown for the mass series of reaction products in Figure 5 . A similar relationship occurs between viscosity of the original oil and viscosity of the 50y0 solutions of the styrenated products, as is shown in Figure 6. There is a definite trend towards products of greater speed of drying when using oils of higher viscosity in the styrenation reaction. Finally, those styrenated products that did not become hazy during the water immersion test were all derived from oils of the higher viscosity range.
August
INDUSTRIAL AND ENGINEERING CHEMISTRY
19%
1591
CONCLUSION
LITERATURE ClTED
From the viewpoint of paint technology, the conclusion can be reached that the most desirable products are obtained by s t y r e nating castor oil that has been dehydrated to a minimum hydroxyl content and then has been bodied to a viscosity approaching 15 poises.
(1) Brice, B. A., and Swain, M. L., J. Optical SOC.A m . , 35, 532-44
ACKNOWLEDGMENT
The work described here is the result of a cooperative program undertaken by The Dow Chemical Company and The Baker Castor Oil Company. The oil samples were made by Baker and w e r ~ c o ~ o l ~ m e r iwith a e d styreneand subjected tocompleteevaluation in the Dow laboratories.
(1945). (2) Griew G. A., and Teot, A. S. (to Dow Chemical Co.), U. 9.
Patent 2,468,748(May 3, 1949). (3) Hewitt, D. H., and Armitage, F., J . Oil 61. Colour Chemists' As-
29,NO.312,109-28 (1946). Peter, in Mattiello, J. J., "Protective and Decorative Coatings," Vol. IV, New York, John Wiley & Sons, Inc., 362405 (1944).
SOC.,
(4) Kam, J.
R E C E I V E D October 18,1949. Presented before the Division of Paint, Var. nish, and Plastics Chemistry a t the 116th Meeting of the A x ~ CHEMI~ i CAL SOCIETY. Atlantic City, N. J.
Inositol-Linseed Fatty Acid Drying Oils d
U
-
J. P. GIBBONS
AND K. M. GORDON' Mellon Institute, Pittsburgh 13, Pa.
A new synthetic drying oil has been prepared from inositol, a hexahydroxycyclohexane, and linseed fatty acids. Esterification of inositol proceeds preferentially to the hexa ester regardless of the molar ratio of linseed fatty acids to inositol. Studies on the rate and extent of esterification with linseed fatty acids indicate that inositol is comparable to other polyols containing secondary hydroxyls. A t 293' and 310' C. the bodying characteristics of the inositol oil above 5 poises viscosity are suggestive of those of oiticica and tung oils. Varnishes prepared from the inositol drying oil and Bakelite resin BR-254 produce films with good drying properties and excellent alkali and water resistance. .4 temperature control apparatus is described for use with an electric heating mantle. With this apparatus the reaction medium could be maintained within *2' C. at 235" C. for periods of 24 hours with a minimum of attention.
I
N R E C E N T years increased attention has been directed
toward the preparation and properties of synthetic drying oils. Interesting and useful oils have resulted from the esterification of linseed fatty acids with polyhydric alcohols such as pentaerythritol, polypentaerythritols, mannitol, and sorbitol. having the following meso-Inositol, a hexah~~droxycyclohexane, stereochemical structure ( 5 , 6 ) ,represents a type alcohol different from those already investigated:
H
.c-HO/OH C,
\H C.OH
H
c--. OH\H C
OH /Or3
$-
The aim in the research reported here was to ascertain the differences in reaction rates and properties that would be effected by the cyclized structure and the presence of only secondary alcohol groups. Although Burns (3) has patented the preparation of oil-modified alkyds with inositol and quebrachitol, there appears t o be no published reference to the employment of inositol in making synthetic drying oils except for that in a recent article by Bolley (1). 1
Present address, College of William and Mary, Williamsburg, Va.
PREPARATION OF INOSITOL ESTERS
The inositol used in this work was the meso form (Corn Products Refining Company). It is a white, crystalline, nonhygroscopic solid, melting a t 224.5' t o 225.5' C. (corrected). The linseed oil fatty acids were of two types, a distilled product (Woburn Chemical Company's Linseedine Supra fatty acids) and an undistilled grade (Spencer-Kellogg Company). The apparatus consisted of a standard tapered three-necked, 3-liter flask having a well for a thermoregulator. The center neck was fitted with a mechanical stirrer. In one side neck a small tube was inserted extending about I inch below the joint to permit the passage of nitrogen over the surface of the reaction mixture. The third neck of the flask was provided with a threeway distilling connecting tube which led to a standard tapered two-necked 500-ml. r e c e i v e r equipped with an upright waterITR cooled condenser. The opening inbthe top of the three-way c o n n e c t i n g tube permitted a thermometer to be immersed in the reaction mixture, The heating unit was a 1 LOAD hemispherical electric mantle with ti thermoregulator To Flask Heater for t e m p e r a t u r e control. The therFigure 1. Temperature Controller moregulator was VT = Variabletransformer; TR = thermoregulator (Femwal A-7802)s SW =. connected to a variswitch; VM voltmeter; SR 100-ohm able t r a n s f o r m e r resistor
@--
I
-
p
~
~
~
