甲醇氯化铵法反应催化剂的研究

Preparation and Performance of the Catalyst for the Synthesis of Methyl Chloride from Ammonia Chloride and Methanol

利用等体积浸渍法,分别以γ-Al2O3以及γ-Al2O3、高岭土和HZSM-5分子筛三种物质的混合物为载体,通过负载钴活性组分制备了氯化铵与甲醇合成氯甲烷的催化剂,根据在固定床反应器中的实验结果对催化剂进行筛选,并在此基础上对所筛选催化剂的制备工艺和操作条件进行优化。结果表明,在氯化铵和甲醇原料比1.1:1,反应温度330～390℃,空速为0.7 s-1的条件下,以γ-Al2O3为载体,负载4%的Co(NO3)2制备得到的催化剂,氯甲烷的收率达到74.2%;而以混合物为载体,负载4%的Co(NO3)2,甲醇的转化率为90%以上,氯甲烷收率最高可达到75.3%。混合型载体的催化剂与γ-Al2O3为载体催化剂的活性相近。制备过程中滴加浓硫酸对催化剂活性提高不显著。

The catalysts for the synthesis of methyl chloride from ammonium chloride and methanol were prepared with equal-volume impregnation method,using γ-Al2O3 and the mixture of γ-Al2O3,kaolin and HZSM-5 molecular sieve as the carrier and cobalt as the active component.The performance of prepared catalysts was investigated in a bench-scale fixed bed reactor.The preparation method and operation conditions were optimized in order to obtain higher yield of methyl chloride.The experimental results showed that the yield of methyl chloride reached 74.2% by the catalyst with γ-Al2O3 as carrier under the conditions of the feedstock ratio of ammonium chloride to methanol 1.1：1,the reaction temperature 330-390 ℃,space velocity 0.7 s-1 and 4% Co（NO3）2 as active component,and the conversion of methanol reached 90% and 75.3% yield of methyl chloride could be obtained by the catalyst with the mixture of γ-Al2O3,kaolin and HZSM-5 as carrier and 4% Co（NO3）2 as active component.It was indicated that the catalytic activities of the catalysts supported with γ-Al2O3 and the mixture supporter were similar.Dropping concentrated sulfuric acid during the preparation of the catalyst was not significant for the increase of catalyst activity.