论文部分内容阅读
以分子筛MSU-1为载体,La、Ce、Cu和K为改性剂,制备了一系列改性的VO_x/MSU-1催化剂,并系统地评价了催化剂的反应活性。采用XRD、H_2-TPR及NH_3-TPD对改性催化剂La1.0V10.0/MSU-1[w(VO_x)=10.0%,w(La2O_3)=1.0%]进行了表征,并考察了最佳反应条件。结果显示:稀土元素La、Ce的加入能提高催化剂的活性,La元素的加入提高了载体MSU-1上活性组分VO_x的分散度,同时也改善了催化剂表面的酸碱性,更加有利于异丁烷氧化脱氢反应的进行。在最佳反应条件下(温度853 K,体积空速4 800 h~(-1),常压,CO_2与异丁烷体积比为3∶1),催化剂La1.0V10.0/MSU-1上异丁烷的转化率为63.6%,异丁烯的产率为52.3%。稳定性实验结果表明:8 h循环后,催化剂V10.0/MSU-1[w(VO_x)=10.0%]上异丁烷转化率降为16.5%,而La1.0V10.0/MSU-1上为28.8%,说明La改性的VO_x/MSU-1催化剂具有更好的稳定性。
A series of modified VO_x / MSU-1 catalysts were prepared using molecular sieve MSU-1 as carrier, La, Ce, Cu and K as modifiers, and the reactivity of the catalysts was systematically evaluated. XRD, H_2-TPR and NH_3-TPD were used to characterize the modified catalysts La1.0V10.0 / MSU-1 [w (VO_x) = 10.0% and w (La2O_3) = 1.0% condition. The results show that the addition of La and Ce can increase the activity of the catalyst. The addition of La can improve the dispersibility of the active component VO_x on the support MSU-1 and also improve the acid-basicity of the catalyst surface, Oxidative dehydrogenation of butane proceeds. Under the optimal reaction conditions (temperature 853 K, space velocity 4 800 h -1, atmospheric pressure, the volume ratio of CO 2 to isobutane is 3:1), the catalyst La1.0V10.0 / MSU-1 The isobutane conversion was 63.6% and the isobutene yield was 52.3%. The results of the stability experiment showed that the isobutane conversion of catalyst V10.0 / MSU-1 [w (VO_x) = 10.0%] was reduced to 16.5% after 8 h of circulation, while that of La1.0V10.0 / MSU-1 28.8%, indicating that La-modified VO_x / MSU-1 catalyst has better stability.