少溶剂固态化学反应制备铵光卤石

Ammonium Carnallite Prepared from a Less-Solvent Solid State Reaction

固态化学反应的热力学分析指出,固态化学反应具有“一旦发生,就必完全”的特征;该特征不会因为少量溶剂的存在而消失。本文使用按1:1摩尔比混合的氯化铵和六水合氯化镁的固体进行反应,只使用刚刚淹没固体的水来促进二者之间的反应,结果发现,在室温下30 min左右,它们全部转化成了铵光卤石(NH_(4)Cl·MgCl_(2)·6H_(2)O,六水合氯化铵镁)。本实验有助于将少溶剂固态化学反应的概念引入学生的知识库,并籍此推进化学过程的绿色化。它还可以使学生学到如何冻结化学反应,使之适合于离位化学反应动力学研究的方法。

Thermodynamics tells that solid state reactions will not stop until they complete,and will not be affected even when a small amount of solvent is used.Here,we report that solid MgCl_(2)·6H_(2)O and solid NH_(4)Cl react to produce NH_(4)Cl·MgCl_(2)·6H_(2)O in half an hour at room temperature,with the help of a little water that just submerges the solids.This experiment will introduce the concept of less solvent solid state reactions and their applications in green chemical processes,and it can also make the student know how to freeze a reaction to fit to the ex situ kinetic studies.