首页 | 本学科首页   官方微博 | 高级检索  
     检索      


The solvent effect of methanol on the dissociation of Bis·H+ from 10 to 40°C
Authors:Roger G Bates  Kazuko Tanaka
Institution:1. Department of Chemistry, University of Florida, 32611, Gainesville, Florida
Abstract:The solvent effect on the acidic dissociation of the protonated base tris(hydroxymethyl)aminomethane (Tris) has been studied in aqueous mixtures of several organic constituents with qualitatively similar results. The dissociation constant of protonated 2-amino-2-methyl-1,3-propanediol (Bis), the analog of Tris with two hydroxy groups, has now been determined in 50 mass % methanol by emf measurements of cells without liquid junction in the temperature range 10 to 40°C. The conventional treatment of the data indicated abnormally low values for the activity coefficient of BisHCl, but an alternate method of calculation with allowance for ion pairing provided no advantage. The pKa in the range from T=283.15 to 313.15 K is given by $$pK_a = 3755.63/T - 24.5127 + 3.56855 In T$$ with a standard deviation of 0.0006 at the seven temperatures. Thermodynamic quantities for the dissociation process and corresponding quantities for the transfer from water to 50 mass % methanol were derived. The implications of the results in terms of selective solute-solvent stabilization are discussed.
Keywords:
本文献已被 SpringerLink 等数据库收录!
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号