2,4-二氨基甲苯和2,6-二氨基甲苯在KY分子筛上的吸附分离

Adsorption separation of 2,4-diaminotoluene and 2,6-diaminotoluene on KY molecular sieve

采用静态吸附实验方法从6种分子筛中筛选出KY分子筛作为吸附分离2,4-二氨基甲苯(2,4-TDA)和2,6-二氨基甲苯(2,6-TDA)的吸附剂,选择性系数为1.54。并对2,4-TDA和2,6-TDA的动态吸附进行了研究,结果表明2,4-TDA和2,6-TDA的平衡吸附量均随温度升高而降低。随溶液中2,4-TDA和2,6-TDA质量分数的增大,穿透时间和吸附平衡时间缩短,且平衡吸附量增大。相同条件下2,4-TDA的平衡吸附容量均小于2,6-TDA的平衡吸附容量,KY分子筛对2,6-TDA具有吸附选择性。甲醇作为脱附剂具有良好的脱附效果。研究了KY分子筛对混合TDA的动态吸附分离,可将2,4-TDA质量分数提高到99.3%,将2,6-TDA质量分数提高到99.82%。用KY分子筛进行2,4-TDA和2,6-TDA的吸附分离是可行的。

KY molecular sieve was selected from six kinds of molecular sieves as the adsorbent for the adsorptive separation of 2,4-diaminotoluene （2,4-TDA） and 2,6-diaminotoluene （2,6-TDA） through the static adsorption experiment, and the selectivity was 1.54. The dynamic adsorption experiments of 2,4-TDA and 2,6-TDA were investigated, and the results show that the equilibrium adsorption capacity of 2,4-TDA and 2,6-TDA decreases with the temperature rise. The breakthrough time and the time of adsorption equilibrium were shorted with the increasing of mass fraction of 2,4-TDA and 2,6-TDA. The equilibrium adsorption capacity of 2,4-TDA was less than that of 2,6-TDA under the same condition. It indicates that the KY molecular sieve has adsorption selectivity to 2,6-TDA. The efficiency of desorption is excellent by using methanol as eluent. 2,4-TDA is enriched to 99.3% （mass fraction） and 2,6-TDA is increased to 99. 82% （mass fraction） with KY molecular for dynamic adsorption separation of the blend of 2,4-TDA and 2,6-TDA. So it is possible to do adsorption separation of 2,4-TDA and 2, 6-TDA with KY molecular sieve.