摘要
以天然气(主要成分是甲烷)为原料制取化工原料,特别是制乙烯近来愈益引人注目.绝大多数作者用金属氧化物作催化剂,进行甲烷氧化偶联制取烃类化合物.用沸石催化剂的报导甚少,仅Anderson,Shepelev,Kowalak等少数作者做了一些工作.本文用Y型及ZSM-5型沸石并负载MnO_x作为天然气转化制烃类的催化剂,发现在我们的实验条件下,可获得较高的转化率和烃类选择性.
The oxidative coupling of methane to higher hydrocarbons (HHC) over several types of zeolite catalyst was carried out in a fixed bed microreactor under atmospheric pressure. Experimental results showed that ( 1 ) the selectivity for HHC over zeolites decreased in the order of BNaZSM-5-NaZSM-5>HZSM-5>HY>NaY, and the higher temperature and lower air/CH4 ratio were beneficial to the formation of HHC; ( 2 ) MnOx supported on acidic zeolite was unfavourable to the oxidative coupling of methane; ( 3 ) after boron introduced into the framework of zeolite, the conversion of CH4 to HHC and the selectivity for C2 were improved; ( 4 ) in the absence of O2, natural gas could be converted over zeolites and MnOx/zeolites, but the catalysts were short-lived.
