A simplified preparation of fully deuterated, high molecular weight hydrocarbons

Abstract

A novel system for the individual preparation of fully deuterated hydrocarbons with 10 to 36 carbon atoms is described. The system permits the use of unsaturated and saturated, cyclic and acyclic starting materials and results in the perdeuterated, saturated equivalent of the starting material. Exchange occurs between hydrocarbon liquid and deuterium gas over carbon-supported, fixed-bed catalysts of Rh, Pt, and Pd at 190–200 °C and results in perdeuterated products of high isotopic and chemical purity. No cracking or structural isomerization occurs under the conditions used, but epimerization of asymmetric carbon atoms does occur. Yields of 35–75% are obtained, the chief losses being due to volatilization and sample withdrawal. The deuterated hydrocarbons prepared by liquid-phase exchange include n-decane-d22, n-dodecane-d26, n-hexadecane-d34, n-octadecane-d38, n-tetracosane-d50, n-octacosane-d58, n-hexatriacontane-d74, pristane-d40, squalane-d62, cyclododecane-d24, 1,2-dicyclohexylethane-d26, and decalin-d18.