在阴离子交换树脂催化剂上合成二丙酮醇的动力学研究

动力学研究表明,在碱性树脂催化剂上丙酮缩合制二丙酮醇是一个1-1级可逆反应,本文对此多相催化的反应机理进行了探讨。

The Kinetics Study on Synthesis of Diacetone Alcohol on Basic Ion Exchange Resin Catalyst

This paper studies on a basic ion exchange resin catalyst that was used in condensation reaction of acetone to prepare diacetone alcohol and find it having good activity and selectivity. The life time of this catalyst is long ,and the method of regeneration of deactivated catalyst is easy. The kinetics experiments on preparation of diacetone alcohol from acetone on this resin catalyst show that the condensation reaction is obviously reversible. The forward and reverse reaction are first-order reaction for concentration of acetone and diacetone res-peptively. This reaction is fond to obey the following rate equation.-dCacetone/dt=k+Cacetone-k-CdiacetoneThe apparent activation energy of forward and reverse reaction can be obtained from each rate constant k+ arid k_ and according to this activation energy theheat of the condensation reaction can be given also. It is - 24kJ/mol. On the basis of the kinetics experiments we suggest that acetone was adsorpted onto theactive site of the resin catalyst first and secondly the adsorpted molecular of acetone decompose to form acetonyl. Then the acetonyl reacts with another molecule of acetone forming diacetone and regenerating catalyst again.The second step is the rate-control step. We also estimate the heat of the reaction by calculating the bond energies of the compounds which were involved in. the condensation reaction. The values of the heat of reaction between the calculating . result and kinetics experiment are very close.