Orientational order in non-alkane chain molecules. Heats of mixing of tetralauryltin, dioctyl ether, trans- and cis-dec-5-ene with linear and branched alkanes

Abstract

Heats of mixing at 25°C have been measured for the following 24 systems: Sn(C₁₂H₂₅)₄ with five linear and three branched alkanes, dioctyl ether with the same alkanes (except C₅), cis-dec-5-ene with trans-dec-5-ene, cis- and trans-decene with n-C₁₂, n-C₁₆, br-C₆, br-C₁₆. Orientational order in long chain non-alkane molecules was investigated. It was found to be present between the chains of Sn(C₁₂H₂₅)₄. Compounds in which the C—C sequence of an alkane is interrupted by C—O—C (dioctyl ether) appear to retain part of the orientational order, but interruption by a double bond (dec-5-ene) destroys the order. The heat of mixing profile of a given compound with the linear alkane series and that of the branched alkane gives information on the orientational order of this compound in the pure liquid state. Correlation of the heats or of the calculated X₁₂ parameter with the Bothorel J orientational order parameter is made.