负载MgO凹凸棒土的催化性能

The Catalytic Properties of MgO Loaded Attapulgit

本文以MgO改性的凹凸棒土为催化剂,对其酸碱性、乙醇转化反应活性、选择性及反应机理进行了研究。结果表明,乙醇转化生成丁二烯需要酸碱中心的协同作用,通过MgO改性凹凸棒土,调变其酸碱性,可显著提高丁二烯产率和选择性,经脱氢、羟醛缩合、加氢、脱水等步骤乙醇转化生成丁二烯。

In the present paper, the preparation of butadiene from ethanol as a model reaction is carried out over attapulgit, acid treated attapulgit and MgO modified attapulgit catalysts. The acidic and basic properties of the catalysts as measured by the poisoning effect of pyridine and phenol on these catalysts, the ethanol conversion activity and the selectivity of butadiene from ethanol together with its mechanism have been studied. The results indicated that the reaction of butadiene from ethanol needs the synergism of both acidic and basic sites. The MgO modified attapulgit improves both acidic and basic properties of the catalyst and the yield and selectivity of butadiene because of better matching of acidic and basic sites. On the 15% MgO/acid treated attapulgit catalyst, a conversion of about 32% and a selectivity of about 62% with respect to butadiene is obtained. Ethanol is converted into butadiene via dehydrogenation, aldol condensation, hydrogenation and dehydration. Both acetaldehyde and crotonaldehyde as intermediates are observed. This novel catalyst may find potential use for those reactions which need synergistic action of both acidic and basic sites of a catalyst.