气相法催化合成二氟甲烷研究

Study on Catalytic Synthesis of Difluoromethane by Gas Phase Method

为克服以往催化剂稳定性较差、易焦化或晶化而失活的缺点,以二氯甲烷和无水氟化氢为原料,在自制新型催化剂的作用下经过2步串联氟化反应制得二氟甲烷。结果表明,在第1反应器温度300℃、空速为2500 h^(-1)、HF/CH_(2)Cl_(2)的摩尔比为25∶1、反应选择1^(#)催化剂的条件下,第2反应器反应温度为300℃、反应选择2^(#)催化剂的条件下,CH_(2)Cl_(2)的转化率为100%,总选择性大于99.9%。该方法具有工艺简单、反应条件温和,催化剂活性好、寿命长的优点。

In order to overcome the shortcomings of poor stability,easy coking or crystallization and deactivation of previous catalysts,difluoromethane was prepared by two-step series fluorination reaction with dichloromethane and anhydrous hydrogen fluoride as raw materials under the action of self-made new catalyst.The results showed that the conversion of CH2Cl_(2) was 100%and the total selectivity was more than 99.9%under the conditions of the first reactor temperature of 300℃,space velocity of 2500 h^(-1),HF/CH2Cl_(2) molar ratio of 25∶1 and 1^(#)catalyst,the second reactor temperature of 300℃and 2^(#)catalyst.This method has the advantages of simple process,mild reaction conditions,good catalyst activity and long life.