Methyl esters of sterculic and malvalic acids were heated under nitrogen in the presence of various hydrogenation catalysts, and the effect on the cyclopropene moiety was established. Similar tests were conducted with cottonseed oil, which contains glycerides of stercutic and malvalie acids. Palladium catalysts, and some palladium compounds which were tested, readily gave cyelopropene-free products, while nickel and platinum catalysts did not. Palladium catalysts freshly activated with hydrogen were not as active as those freed of adsorbed hydrogen. The l Catalysts could be reused. Heating cottonseed oil (0.73% cyelopropenes, calculated as trimalvalin) with 0.02% palladium, as a 10% palladium-on-carbon catalyst, gave a cyclopropene-free oil after 2 hr at 150 C. The treated oil was unaltered in appearance, and the noncyclopropene components were unaffected. I~Ieating methyl sterculate with palladium catalyst produced a mixture of unsaturated condensation products and a number of unsaturated monoesters of practically unchanged molecular weight. The palladium treatment was shown to cleave the cyclopropene ring and produce methyl and methylene substituted fatty acid groups.
Solubilities of six cottonseed oil fatty acid methyl esters in metha‐nol have been determined. The esters were: methyl oleate, methyl linoleate, methyl malvalate, methyl dihydromalvalate, methyl sterculate and methyl dihydrosterculate. The solubility/temperature data are presented in graphical and tabular form.
The hydrogenation of cyclopropenoid acids and their relative reactivities during hydrogenation as compared to linoleic and oleic acids were examined. Pure methyl sterculate and purified Sterculia foetida oil and its methyl esters, which have a cyclopropene content more than 60 times that of cottonseed oil, were used for the hydrogenation experiments. Nickel, palladium and platinum catalysts were used. The effect of temperature and type of catalyst Were demonstrated in a series of hydrogenation experiments of safflower and S. foetida oil mixtures, and methyl oleate and methyl dihydrosterculate mixtures. Partial hydrogenation of methyl sterculate formed as many as twenty compounds in addition to the cyclopropenoid derivatives. Most of these compounds were monounsaturated. The cyclopropene group hydrogenated very readily compared to the 9,12-diene system in linoleate. The cyclopropane group obtained by hydrogenating the cyclopropenoid acids group was quite resistant to further attack by hydrogen and nickel catalyst had little effect. With palladium catalyst, a temperature of 180 C was necessary for the reaction to go to completion. Platinum in acetic acid was a good system for hydrogenolysis of the cyclopropane group at 80 C.
A simple procedure for esterifying glycerides without interesterification occurring would be highly useful for preparing on a large scale a number of tailor‐made fats, including cocoa butter‐like fats. Such esterifications were carried out by employingp‐toluenesulfonic acid as catalyst and continuously removing the water of esterification by azeotropic distillation with aliphatic hydrocarbons or by stripping with vaporized hydrocarbons. Even thoughp‐toluenesulfonic acid rapidly disproportionated 1‐monostearin, even at 120C, apparently esterification was faster and only a moeerate amoung of ester‐ester interchange and acidolysis occurred. Diacid glycerides might be prepared from monoglycerides by the procedure which was employed. Saturated diglycerides were esterified with oleic acid with little ester‐ester interchange or acidolysis occurring; however, intraesterification was extensive. The reaction between 1,3‐distearin and oleic acid yielded approximately 75% 1‐oleodistearin and 25% 2‐oleodistearin. Saturated diglycerides were esterified with sebacic acid, again with little or no interesterification occurring.
Das Verhalten der Cyclopropencarbonsäureester (I) und (II) sowie von Baumwollsaatöl (das 0,5 ‐ 1% der beiden Säuren als Glyceride enthält) beim zweistündigen Erhitzen auf 150°C unter Stickstoff in Gegenwart verschiedener Hydrierungskatalysatoren wurde untersucht.
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