INDUSTRIAL AND ENGINEERING CHEMISTRY
2374
TABLE VIT. SUMMARYOF DEVIATIONS Mixture Ethane, z( Propylene, zj
1 0.1861 0.8139
2 0.4033 0.5967
3 0.6016 0.3984
Average % Deviation of f i , 0.60 to 9.0 Moles/Liter 1000 c. 1.44 0.85 1.13 125 1.22 0.67 0.87 130 1.02 0.52 0.66 175 0.85 0.40 0.42 200 0.70 0.30 0.54 225 0.56 0.23 0.37 250 0.18 0.19 0.45 Average 0.89 0.45 0.60 Averageforall4mixtures = 0.61%.
P*aalo.)
a
mole fraction, propylene
M
=I
compressibilityfactor = -
PV
0.7998 0.2002
0.69 0.58 0.49 0.40 0.31 0.2R 0.50
and 1.0 to 9.0 moles per liter for each mixture. The computed compressibility factors were compared with the experimental compressibility factors a t the same density. A summary of the deviations is shown in Table VI1 where ~ ~ v i ~% t =Ii (Mobs. ~ ~ ,
zf 4
0.81
100
Mobs.
NOMENCLATURE
Ao, a, BO, b, CO,c, a,y, = BenedictWebb-Rubin equation of state constants d = density, moles per liter P = pressure, atmoospheres T = temperature, K. = t o C . 273.16 liter atm. R = gasconstant = 0.0820544 gram mole, ’K. u = volume, liters/moie zi = mole fraction, ethane
+
Vol. 42, No. 11
RT
ACKNOWLEDGMENT
R. L. Motard and I. Leibson contributed to the work by assisting with the experimental measurements. The financial assistance of the Shell Chemical Company in the form of a fellowship is gratefully acknowledgcd. LITERATURE CITED (1)
Beattie, J. A.,Hadlock, C. J., and Poffenberger, N., J . Chem.
Phys., 3, 93 (1935). (2) Beattie, J. A., and Ikehara, S., Proc. A m . A d . Arts. Sci., 64, 127 (1930). (3) Beattie, J. A,, Stockmayer, W. H., and Ingeraoll, H. G., J . Chem. Phys., 9,871 (1941). (4) Besttie, J. A,, Su,C., and Simard, G. L., J . Am. Chem. Soc., 61, 926 (1939). (5) Benedict, M., Webb, G. B., and Rubin, L. C., J . Chem. Phys., 8, 334 (1940). (6) Ibid., 10,747 (1942). (7) Cherney, B. J., Msrchman, H., and York, R., Jr., IND. ENG. CHEM.,4 1 , 2 6 5 3 (1949). (8) Lu, H., Newitt, D. M., and Ruhemann, M., Proc. Roy. SOC. (London),A178,506 (1941).
(9) Marohman, H., Prengle, H. W., Jr., and Motard, R. L.,
IND.
ENQ.CHEM., 4 1 , 2 6 5 8 (1949). (10) Reamer, H. H.,Olds, R. H.,Sage, B. H., and Lacey, W. N., Ibzd., 36, 956 (1944). RECEIVED March 17, 1950. This work was abstracted from the thesis presented by H. William Prengle, Jr., to the committee on graduate degrees of the Csrnegie Institute Technology, Pittsburgh, 13, Pa., in partial fulfillment of requirements for the degree of doctor of science.
Plasticizers from Lactic Acid n-ALKYL CARBONATES OF VARIOUS ESTERS OF LACTIC ACID C. E. REHBERG, MARION B. DIXON, T. J. DIETZ, AND P. E. MEISSI Eastern Regional Research Laboratory, Philadelphia 18, Pa.
Thirty-five plasticizers made by acylating esters of lactic acid with n-alkyl chloroformates are described. Boiling points of the plasticizers and compatibilities with cellulose acetate and polyvinyl chloride (95% vinyl chloride copolymer) were determined. Also reported are the tensile strength, modulus at 100% elongation, ultimate elongation, and brittle point of each plasticized vinyl composition. As indicated by modulus and brittle point, many of the esters are more efficient than di-2-ethylhexyl phthalate as plasticizers for the vinyl resin.
I
NCREASXNG demand for plasticizers has led to considerable work in the authors’ laboratory on the preparation and evaluation of high boiling lactic acid derivatives as plasticizers. Because lactic acid is a hydroxy acid, its simple esters can be aoylated with mono- or polybasic acids to make diesters of relatively high molecular weight. The presence of at le& two ester groups in these compounds makes them compatible with many synthetic resins. Earlier papers reported the use a8 plasticizers of diethylene glycol biscarbonates (10),succinates (II), adipates (8, 9, I I ) , aebacates (9, If), maleates ( 9 ) , phthalates (9, 11) and lauratcs ( 1 ) of various lactates, as well as some esters of polyacetic acid (8). The present paper presents data on 35 n-alkyl carbonates I
Present addwss, Thiokol Corporation, Trenton, N. J.
of lactates made by the reaction of alkyl chloroformates with the lactates. The preparation, physical properties, and analyses of these compounds have been reported elsewhere (6-7). Table I shows boiling points of the esters and their compatibility with cellulose acetate as well a.s some properties of the plasticized vinyl chloride resin. When R’ was an alkyl group and R and R’ together contained a total of about 13carbon atoms, the plasticizers had boiling points above that of dibutyl phthalate (148”C. a t 1mm.). A total of about 18 carbon atoms in R and R’ was required to produce a compound having a boiling point as high as that of di-2ethylhexyl phthalate. Esters having a total of not more than about 10 carbon atoms in the groups R and R’ were compatible with cellulose acetate when R’ was an alkyl group. If R’ contained one or more ether linkages, the compatibility was improved so that about 13 carbon atoms in R and R’ could be tolerated. Ether linkages in already highly oxygenated molecules caused decreased compatibility of the esters with the vinyl chloride resin, with the result that most of them bled out of the resin on aging. The decyl carbonate of decyl lactate apparently exemplifies th? opposite extreme in that its incompatibility with the vinyl resin is presumably due to its preponderantly hydrocarbon nature. The hexyl carbonate of diethylene glycol dilactate [CaHlrOCOOCH(CH~)COOCH&Ha]~O is unique in that it is a very
INDUSTRIAL AND ENGINEERING CHEMISTRY
November 1950 ~~
237 5
~~
TABLE I. BOILINGPOINTS OF %-ALKYL CARBONATES OF VARIOUS LACTATES (ROCOOCH(CHa)COOR’) AND PROPERTIES OF THE PLASTICIZED RESINS
R Octyl Decyl Amyl Hexyl Octyl Decyl Dodecyl Amyl Hexyl Ethyl Ethyl Ethyl Butyl Butyl Butyl Ethyl Rutyl Hexyl Octyl Dec 1 DoZcyl Ethyl Amyl Decyl Ethyl Amyl Octyl Decyl Dodecyl Hexyl Hexyl Ethyl Hexyl
R’
Butoxyethyl Butoxyethoxyethyl Butoxyethoxyethyl Butoxyethoxyethyl Butoxyethoxyethyl Butoxyethoxyethyl Hexyloxyeth I Phenox yeth yy Diethylene glycold Diethylene glycol
Formula
CmHasOa C11Hat.07
~irHazO7
CnoHssO, CzdhzO7 CzrHeO7 CisHs4Oe CisHzaOn CiRHnrOii CnrHiiOii
Mol. Wt.
374.5 306.4 348 3 390.5 418.6 446.6 346.5 838.4 394.4 606.6
Boiling Point#, C., at Various Pressure* with 0.01 0.1 1.0 10 Cellulose mm. mm. nim. .4cetatea mm. 82 117 162 102 138 184 75 109 154 85 120 166 102 139 186 120 158 207 134 174 226 117 81 165 136 184 99 206 256 166 135 99 180 120 160 208 150 193 246 71 104 150 102 185 139 205 156 117 225 174 133 85 164 120 136 100 182 115 201 153 132 171 219 186 147 234 161 253 202 153 107 71 136 99 184 183 142 236 I 109 107 143 188 C 78 168 128 217 97 148 189 241 115 161 I 204 258 127 220 174 277 I 138 125 164 212 I 94 142 182 232 C 110 200 249 160 C 128 244 296 C 202 167
F‘
Properties of Plastioized Polyvinyl Chloride b ~~~~~l~ Brittle strength, R l o d ~ l ~Elonga~, point, Coilrimtilb./sn. IWw. tion, C. hilityC inch % inch C 44 920 290 c 280 47 1070 -41 C 1045 290 -40 c 1050 340 c 260 48 1140 47 c 1130 380 50 C 1190 320 C 250 37 1010 43 C 1020 360 I 46 1340 190 G 48 I090 275 -45 c 260 1290 C -37 1460 320 C 220 -7 1880 c 340 49 790 -55 260 840 -61 290 1360 -9 C 230 1860 Bid 280 19 1240 Bled 23 1120 290 Bled 30 1350 310 Bled -37 340 1290 Bled -38 1350 310 C -32 275 1310 40 300 1260 YCI -55 1260 300 2985 -42 1360 310 2960 c 43 350 3060 990 Bled 48 300 2880 1010 Bled -51 340 1100 3100 48 1290 290 2850 pfCd 53 310 2890 1080 Bled -24 350 3260 1300 I 18 21 10 azo 3370 c -25 1330 360 3440
-
-----
E
--
-
--
AB‘ed
-
Control - 32 c 1600 290 240 I 3070 (Di-2-ethulhexul phthalate) CziHaoOi 390.5 I20 153 192 Films. that oontained 20% lastioiser (FM-6 resin Hercules. Powder Company). C, compatible; I, incompatible; CI, borderline. b Vin lite VYDR (06% vinyfchloride r o olymer) that contained 35% lastioizer. a If t i e sample wm greasy when preps& it was conaidered incompati8le; “bled” indiaates that the sample was dry when new but became grelrss after wveral months etornge J Diethylene glycol dhactate bis(ethy1 carbonate>-i.o., [C~H~OCOOCH(CHa)COOCHaCHzl~O.
high boiling ester yet is fully compatible with both cellqlose acetate and polyvinyl chloride. As plasticizers for vinyl chloride resins, the ethyl carbonate of hexadecyl lactate, the butyl carbonate of dodecyl lactate, the amyl carbonate of butoxyethoxyethyl lactate, the hexyl carbonates of diethylene glycol dilactate and hexyloxyethyl lactate, and the dodecyl Carbonate of butyl lactate appear to be of most interest, as judged by their boiling points and the moduli and brittle points of the plasticized resins. BOILINGPOINTS.The boiling points shown in Table I were read from modified Cox charts ( 4 ) prepared from boiling points determined with an improved tensimeter still (8). The lower boilingesters were f i s t distilled through a 24-inch Vigreux column; the higher boiling ones were distilled through an alembic still to isolate relatively pure fractions. The pure fractions obtained were used for determination of physical properties and for plas\ ticizer screening testa. CELLULOSEACETATECOMPATIBILITY. The resin used w&s Hercules Powder Company’s high-acetyl type FM-6. Twenty per cent plasticizer was used in all cases. The resin and plasticizer were dissolved in acetone (5% solution), and the solution was poured on glass plates, which were then placed in closed boxes so that the solvent would evaporate slowly (24 to 36 hours). The films were stripped from the glass, hung in an oven a t 80’ C. for 1 hour, and then examined. If clear and dry, they were considered compatible; if greasy, or if white spots were present, they were considered incompatible. EVALUATION IN VINYLRESIN. The details of the procedures used in compounding and testing the vinyl plastic have been described (10). The test compositions were: Vinylite VYDR Basic lead carbonate Stearic acid Plaaticiser
-Pad* -_.63.5 1.0 0.5 a5.0
Brittle points were determined with strips cut from molded sheets 0.08 inch thick. The equipment was similar to thrtt described by Selker, Winspear, and Kemp (18). Tensile strength, modulus a t 100% elongation, and ultimate elongation were determined with H Rrott IP-4 tester lotid~da t 80 pounds per minute. LITERATURE CITED
Fein, M. L., and Fisher, C. H., J. Org. Chem., 15, 530 (1950). Filachione, E. M., Costello, E. J., and Fisher, C. R., presented before the Division of Paint, Varnish, and Plastics Chemistry, at the 112th Meeting of AM. CHEM.Soc., New York, N. Y. Ratohford, W. P., and Rehberg, C. E., Anal. Ch6m., 21, 1417 (1949).
Rehberg, C. E., IND.ENO.CHEM.,42,829 (1950). Rehberg, C. E., and Dixon, Marion R . . J . Org. Chenc., 15, 585 (1950). Ibid., in press.
Ibid.,in press. Rehberg, C. E.,and Dixon, Marion B., presented before Division of Paint, Varnish, and Plastics Chemistry a t the 116th Meeting of AM. CHEM.SOC., Atlantic City, N. J. Rehberg, C. E., Dixon, Marion B., and Dieta, T. J., presented before the Division of Paint, Varnish, and Plastics Chemistry, 117th Meeting of AM. CHEM.SOC.,Detroit, Mich. Rehberg, C. E., Dixon, Marion B., Dieta, T. J., and Fisher, C. H., IND. ENQ.CHEM.,42, 1409 (1950). Rehberg, C. E., Dixon, Marion B., and Miess, P. E., presented before the Division of Paint, Varnish, and Plastics Chemistry at the 113th Meeting of AM.CHEM.SOC.,Chicago, Ill. Selker, M. L., Winspear, G. G., and Kemp, A. R., IND.Em.. CHEM.,34, 157 (1942). RECEIVED June 24, 1950. Presented in part before the Division of Paint, Varnish, and Plastics Chemistry a t the 114th and 117th Meetings of the AMERICAN CEEMICAL SOCIETY, Washington, D. C., and Detroit, Mich. The mention of specific brands is not to be construed as an endorsement or recommendation of these brands by the Dopartment of Agriculture over others not mentioned.
