Compensation effect with Rochow synthesis

The apparent activation energies and pre-exponential factors for the Rochow reaction, determined from reaction rate measurements at 280–360C, strongly change, if contact masses are varied with respect to promoters, to the copper component's nature and percentage as well as to the silicon type. With each variation, the activation parameters consequently follow the same Cremer-Constable relation. The isokinetic temperature is in the range 330 ± 20 C, i.e., within the region of the reaction temperatures. This implies that the sequence of activities of compared contact masses can be reversed by a mere temperature variation. This may be a reason of contradictions in the literature on Rochow synthesis.     

Cuticular hydrocarbons of tsetse flies II:Glossina fuscipes fuscipes,G. palpalis palpalis,G. p. gambiensis,G. tachinoides,andG. brevipalpis

The alkanes (methylalkanes) were analyzed from both sexes of four members of thepalpalis group of tsetse flies,Glossina fuscipes fuscipes, G. palpalis gambiensis, G. palpalis palpalis, G. tachinoides plus onefusca group member, G. brevipalpis, to determine structures, abundances, and the presence of unique or specific methylalkanes. These insects are unique in that trimethylalkanes were major components except in femaleG. tachinoides and both sexes ofG. brevipalpis where 2-methylalkanes were the major components. The identification of novel long-chain tetramethylalkanes, including 11,15,19,23-tetramethylpentatriacontane, a minor component of femaleG. f. fuscipes, G. p. gambiensis, andG. p. palpalis, is reported here. Tetramethylalkanes were significant components of both sexes ofG. brevipalpis. The major tetramethylalkane in G.brevipalpis is 3,7,11,15-tetramethylhen-triacontane. The use of the methylalkanes as taxonomic indicators in tsetse is discussed.     

400t／a苯基氯硅烷直接法合成工艺

本文介绍了４００ｔ／ａ苯基氯硅烷直接法合成工艺及其技术经济指标。