制备条件对碳化钼催化剂及正己烷异构化的影响

Effects of preparation condition on molybdenum carbide catalyst and isomerization of n-hexane

采用程序升温还原法制备B-Mo_2C/SAPO-11催化剂,研究制备条件对β-Mo_2C/SAPO-11催化剂上正己烷异构化的影响。XRD分析及实验结果表明,升温速率过快导致碳化程度较低,钼相多为单质钼,升温速率小于2℃·min^(-1),催化剂制备效果较好;碳化终温对碳化程度影响较大,终温过低使碳化后的样品含有较多的MoO_2。对正庚烷和正己烷作为碳源的碳化效果进行比较,结果表明,正己烷作为碳源较合适。催化剂中碳化钼负载质量分数为15%,催化剂上金属组分的加氢和脱氢活性与SAPO-11载体的异构化活性达到最佳平衡。

SAPO-11 molecular sieve supported molybdenum carbide catalyst β-Mo2C/SAPO-11 was prepared by temperature-programmed reduction method. The effects of preparation condition on isomerization of n-hexane over β-Mo2C/SAPO-11 were investigated. The experimental results showed that fast heating rate resulted in low carburization degree and the main phase of molybdenum was molybdenum metal. The active β-Mo2C could be obtained with the heating rate below 2 ℃ · min^-1. The final temperature of car- buration had great influence on carburization degree. Molybdenum phase contained more MoO2 at low final temperature of carburation. Compared with n-heptane, n-hexane was the better carbon source. The hydrogenation and dehydrogenation activity of the metal on the catalyst with Mo loading 15wt% and the isomerizationactivity of the support SAPO-11 reached the best balance.