Kinetics, medium, and deuterium isotope effects in the alkaline decomposition of quaternary phosphonium salts. IV. Tetraphenylphosphonium chloride in tetrahydrofuran-water mixtures

Author:

Khalil Fayez Y.,Aksnes Gunnar

Abstract

The third-order rate constants of the reaction between tetraphenylphosphonium chloride and sodium hydroxide in binary tetrahydrofuran—water systems have been determined as a function of temperature. Increasing the THF content of the reaction medium up to 70% (v/v) results in a ca. 106-fold rate acceleration at 25 °C. This is explained as due to increased desolvation of reactants as well as an opposite effect on the transition-state solvation in THF-rich media. The rate in deuterium oxide is higher than in water and the kinetic isotope factor k′DO−/k′110− depends strongly on temperature. The inverse proportionality of rate to the water concentration of medium showed that a large number of water molecules (about 13) is to be removed from the solvation sheaths of reactants before formation of the activated complex. The thermodynamic activation parameters have been derived and expressed as functions of the composition of the medium. It is found that ΔH decreases by about 17 kcal/mol over the range 0–70% THF, while ΔS decreases by about 29 cal mol−1 deg−1 over the same range. As a result, ΔG shows a net decrease of 8 kcal/mol indicating partial compensation between ΔH and TΔS.

Publisher

Canadian Science Publishing

Subject

Organic Chemistry,General Chemistry,Catalysis

Cited by 9 articles. 订阅此论文施引文献 订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3