Significant discrepancies between van't hoff and calorimetric enthalpies. II

✍ Scribed by Yufeng Liu; Julian M. Sturtevant

• Book ID: 105356355
• Publisher: Cold Spring Harbor Laboratory Press
• Year: 1995
• Tongue: English
• Weight: 235 KB
• Volume: 4
• Category: Article
• ISSN: 0961-8368
• DOI: 10.1002/pro.5560041212

✦ Synopsis

Abstract

Isothermal calorimetric titration of 18‐crown‐6 ether with BaCl~2~ in pure aqueous solution over the temperature range 7‐40 °C gives precise binding constants and enthalpy changes. Nonlinear least‐squares fitting of the binding constants to the integrated van't Hoff equation, including a temperature‐independent change in heat capacity, leads to van't Hoff enthalpies that differ significantly from the observed calorimetric enthalpies. This perplexing discrepancy appears at present to be very widely occurring.