December 1950
INDUSTRIAL A N D ENGINEERING CHEMISTRY
presented in Table I. These data were obtained in the same manner as the results in Figures 5 and 6. The effects of pressure on yields from 61.5% acid a t a propylenesulfuric acid mole ratio of 1.06 are shown in Figures 7 and 8. These demonstrate that by sufficiently reducing the pressure, yields of alcohol can be obtained from 61.5y0 acid which are comparable to the yields a t atmospheric pressure from 46.0oJo acid with the same R value. It was of interest to determine yields at still higher acid concentrations, approaching the acid used for absorption of the olefm in strength. These data are presented in Table I1 for 69.5’% acid, a t both atmospheric and reduced pressure. For this case, although yields of isopropyl alcohol may be considerably improved by lowering the pressure, it appears unlikely that they cftn be made comparable to those from more dilute acid a t any economically feasible vacuum.
TABLE I. COMPOSITION OF DISTILLATE AND YIELDS OF PRODUCTS (46.Oye acid, 1.05 propylene-sulfuric acid mole ratio, distilled a t
atmosphenc preasure)
Weight % Compoeition of Distillate 77.9 Isopropyl alcohol IBopropyl ether 2.0 Water 20.1
?+, Yield Based on Propylene Isopropyl alcohol 95.0 Isopropyl ether 2.9 2.1 Propylene
TABLE 11. COMPOSITION OF DISTILLATE AND YIELDS OF PBODUCTS (69.5% acid, 1.06 propylene-sulfuric acid mole ratio)
Weight % Composition of Distillate 1 atm. 271 mm. Iaopropyl alcohol 34.8 56.6 Isopropyl ether 41.2 27.0 24.0 16.4 Water
% Yield Based on Propylene Isopropyl alcohol 26.5 Isopropyl ether 36.8 Propylene 36.7
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LITERATURE CITED
49.6 27.9 22.5
The yield of alcohol from 61.5% acid a t any R value is much poorer a t atmospheric pressure than is usually obtained in commercial processes using more dilute acid. For comparative purposes data obtained for 46.0% acid with a propylene-sulfuric acid mole ratio of 1.05 and distilled a t atmospheric pressure are
(1) Evans, P.N.,snd Albertson, J. M., J . Am. Chem. Soc., 39,456-61 (1917). (2) Faaia, A.,M.S. thesis, Colbmbia University, 1948. (3) Frere, F. J., IND.ENO.CHEM.,41,2365-7 (1949). (4) Goldschmidt, H., Haaland, H., and Melbye, R. S., 2. physik. Chem., B143,278-86 (1929). (5) Goldschmidt, H., and Melbye, R. S., Zbid., B143,139-56 (1929). (6) Medwedew, S.S.,and Alexejewa, E. N., Bm., 65B,131-3 (1932). (7) Robey, R.F.,IND.ENG.CEEM.,33,1076-8 (1941). (8) Suter, C. M., and Oberg, E., J . Am. Chem. Soc., 56,677-9 (1934). RECEIVED April 14, 1950. From a thesis submitted by Robert W. Schrage in partial fulfillment of the requirements for the degree of master of science in the School of Engineering, Columbia University. Contribution No. 5 from the Chemical Engineering Laboratories, Engineering Center, Columbia University, New York, N. Y.
Aging Studies on Redox Polymers EFFECT OF IRON C. R. PARKS, J. 0. COLE, AND J. D. D’IANNI The Goodyear Tire 6% Rubber Company, Akron, Ohio T h e stability of GR-S type polymers and vulcanizates prepared by the iron-redox and mutual recipes have been compared by oxygen absorption measurements during accelerated aging. Iron-redox polymers are less stable in general toward oxidation than polymers made by the mutual system. Vulcanizates derived from redox polymers are only very slightly inferior in stability, however, to vulcanizates prepared from mutual type polymers. Evidence shows that soluble iron is a factor in the poor stability of some iron-redox polymers toward oxygen,
sBLE
‘On has a pronounced effect On the aging GR-S p o l p e r but Only a ‘light effect On the
Of
the
1’
Polymerization recipes currently employed for the commercial production of “cold rubber” contain iron in the form of the ferrous pyrophosphate complex. In view of the possible adverse effect of iron on the aging of GR-S type polymers, a comparison was made of the aging of GR-S prepared by the ironmredoxand by the mutual polymerization systems.
~~h~of GRS polymers and vulcanizates was evaluated by oxygen absorption measurements and by the change in physical properties during accelerated aging. In view of the uncertainty as t o the chemical form in which iron is present in iron-redox polymers after coagulation of the latex, the activity of iron in various chemical forms was measured. The amount of soluble iron that
would catalyze decomposition of the polymer was also determined. EXPERIMENTAL
In the discussion which follows, a mutual polymer ( 4 ) refers to a GR-S type emulsion polymer prepared with potassium persulfate and mercaptan (thiol). An iron-redox polymer refers to a polymer prepared with a cumene hydroperoxide, ferrous pyrophosphate, and sugar system (6). Oxygen absorption measurements were made in oxygen by the volumetric method employing apparatus similar to that described by Shelton and Winn ( 8 ) . All pilot plant and laboratory prepared samples contained phenyl-p-naphthylamine 8s antiofidant. Polymers and vulcanizates were compared a t the same antioxidant content. Polymers were analyzed for phenyl-p-naphthylamine by the ultraviolet spectrometric method and the antioxidant content of each sample in a given’ series adjusted to a predetermined value (1.25% wherever possible). The commercial samples were obtained from various Rubber Reserve plants and contained B-L-E (a high temperature reaction product of diphenylamine and acetone) as an antioxidant. The antioxidant contents were not adjusted as they were within specification limits (1.25 * 0.25%). The polymer samples were prepared by coating a test tube with
INDUSTRIAL AND ENGINEERING CHEMISTRY
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Figure 2. Comparisonof Oxygen Absorption Rates of IronRedox Polymer DS. Iron-Free Mutual Polymer
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