NaOH改性ZSM-5分子筛在苯、甲醇烷基化反应中的应用

用NaOH溶液对高硅ZSM-5分子筛进行处理,考察其应用于苯-甲醇烷基化反应过程的最佳处理条件,并用XRD、SEM、XRF、NH3-TPD、TPO、BET等手段对试样进行表征。结果表明,NaOH在脱除分子筛硅物种的同时,也会脱出晶粒表面附着物,暴露出更多的酸性位,形成一定量的介孔,进而影响苯-甲醇烷基化性能。当NaOH处理量为2.4 mmol/gcat时,在液体积空速为85 h-1下,烷基化反应中苯的转化率达到38%,相比处理前提高了近16%,且积炭量低,稳定性好。

Application of NaOH modified ZSM-5 zeolite in alkylation of benzene and methanol

High-silicon ZSM-5 zeolite was treated with NaOH solution to investigate the effect of modification on benzene-methanol alkylation. The physicochemical properties of the samples were characterized by XRD, SEM, XRF, NH₃-TPD, TPO, and BET. The results showed that NaOH treatmeng removed the molecular sieve silicon species and the surface deposits, revealed more acid sites, formed certain amount of mesopores, which affected the alkylation performance of benzene-methanol. When the NaOH treatment amount was 2.4 mmol/g_cat, the conversion rate of benzene in the alkylation reaction reached 38% at a liquid volume space velocity of 85 h^-1, which was nearly 16% higher than that before treatment, and the modified catalyst had low carbon deposition and better stability.