Determination of the total unsaturation of tung oil by catalytic hydrogenation

Abstract

Summary The use of catalytic hydrogenation as a quantitative method for the measurement of total unsaturation in tung oil and related products containing conjugated unsaturation, has been investigated. The apparatus, which comprises essentially a gas burette, manometer, and reaction vessel, is relatively simple, is constructed entirely of glass, and employs an externally mounted magnetic agitator. The weighed sample and platinum catalyst are suspended in glacial acetic acid during hydrogenation. In the case of tung oil and partially hydrogenated tung oil, heating of the reaction vessel is necessary to complete the hydrogenation. Hydrogen iodine values representing the total unsaturation in domestic and imported oils, alpha‐ and beta‐eleostearic acids, the residual unsaturation in partially hydrogenated tung oils, and the unsaturation of other organic materials are reported. Tung oil and eleostearic acid gave hydrogen iodine values of approximately 240 and 271, respectively. Analytical hydrogenation, as described, is particularly well suited for the determination of unsaturation in conjugated systems.

Empirical Viscosity Relations of Heated Vegetable Oils

“…Some samples of linseed and tung oil and their methyl esters were hydrogenated prior to molecular distillation. The hydrogenation apparatus was a modification of that described by Pack and coworkers et al (4)• The platinum on silica catalyst was prepared according to Vandenheuvel (9) and cyclohexane was used as the solvent. Extraction of the catalyst with ether in a Soxhlet-type extractor for 3 hours resulted in complete recovery of the reduced oil or ester.…”

Determination of the fatty acid composition of partially hydrogenated tung oils

“…al*d determined by measuring the absorption at 233 m~, making corrections for various interfering materials (6). The total unsaturation of each hydrogenated oil was obtained by quantitative hydrogenation (7) and checked by a new bromination procedure (9). The content of saturated fatty acids was obtained by a Bertram oxidation procedtrre (2) Enot~gh oil to yield 1.0-1.5 g. of saturated acids (about 35 g. for tung oil) was placed in a 500-ml.…”

Notes- Preparation of Methyl β-Hydroxybutyrate from Propylene Oxide, Carbon Monoxide, Methanol, and Dicobalt Octacarbonyl.

“…The next day, water was added, the mixture extracted with ether, and the ether dried and evaporated. The crude methyl acetoacetate was treated with 2,4-dinitro-phenylhydrazine11 to yield a 2,4-dinitrophenylhydrazone, (7) Methyl ß-hydroxybutyrate. /3-Butyrolaetone was prepared according to Johansson's9 method of heating a well stirred aqueous solution of sodium /3-bromobutyrate at 40°for 6 hr.…”