【摘要】 采用HZSM-5分子筛催化剂,在固定床微反装置上考察了原料气加料顺序对异丁烯直接胺化反应的影响。用过渡应答技术对原料异丁烯、氨及产物叔丁胺在催化剂表面的吸附行为进行了研究,用热分析、原位红外光谱表征了催化剂在不同反应条件下的吸附性能。研究结果表明,在该反应体系中,催化剂表面氨的吸附占主导地位,异丁烯直接胺化反应经由以下机理:氨优先吸附于催化剂表面的B酸中心,形成铵正离子;而后与气相中的异丁烯反应,生成中间物种叔丁基正离子;叔丁基正离子与气相的或化学吸附的氨作用生成叔丁胺。更多还原

【Abstract】 Effects of feeding order of different feedstocks on direct amination of isobutene to tert-butylamine over HZSM-5 molecular sieve catalyst in fixed-bed microreactor were studied.The adsorption behaviors of isobutene,ammonia and tert-butylamine on surface of the catalyst were investigated by means of transient response method.The adsorption properties of catalyst under different reaction conditions were studied by thermal analysis and in-situ IR.At amination temperature the preferential feeding order is:feeding ammonia to the system first,followed by mixture of ammonia and isobutene.Surface of catalyst is mainly occupied by ammonia.The amination mechanism is inferred as follows:firstly,ammonia is adsorbed on B-acid sites of the catalyst,then the chemisorbed ammonium cations react with gaseous isobutene and tert-butyl cations form as intermediate species,and finally the cations react with gaseous or chemisorbed ammonia to produce tert-butylamine.更多还原