化学气相沉积三甲基氯硅烷制备两亲性HZSM-5沸石

Preparation of Amphiphilic HZSM-5 Zeolite by Chemical Vapor Deposition of Trimethylchlorosilane

以三甲基氯硅烷((CH3)3SiCl)为改性剂,采用化学气相沉积法对HZSM-5沸石外表面进行修饰,再通过控制后处理抽空温度,制得两亲性沸石样品.在沉积过程中,改性剂与沸石外表面末端硅羟基作用形成亲油性基团,使得样品主要呈现出亲油性;经423～523K抽空处理后,沉积的(CH3)3Si基团发生Si-C键断裂而脱附出1～2个甲基,样品表现出两亲性能.该改性过程对HZSM-5沸石的孔道大小和内表面性质影响很小.在乙酸异戊酯相界面催化水解反应中,该两亲性沸石分布于水/油两相界面,表现出明显高于亲水性母体HZSM-5沸石的催化活性.

Amphiphilic HZSM-5 zeolite particles were prepared by the chemical vapor deposition （CVD） of trimethylchlorosilane （（CH3）3SiCl） followed by heating and evacuation. During CVD, （CH3）3SiCl reacted with terminal silanols on the external surface of HZSM-5 to generate hydrophobic groups. The resulting zeolite particles were hydrophobic. During heating of the zeolite particles to 423-523 K and evacuation, the （CH3）3Si groups decomposed by SiC bond breaking, and one to two of the CH3 groups were removed off, which resulted in amphiphilic zeolite particles. This modification has little effect on the pore size and internal surface. In the phase-boundary catalytic hy- drolysis of isoamyl acetate, these amphiphilic zeolite particles were located at the water-organic boundary and exhibited better catalytic activity than the parent zeolite.