论文部分内容阅读
用微反断流催化色谱技术研究了HZSM-5催化剂上乙醇脱水生成乙烯的反应,发现表现反应速率常数k与反应是在催化剂表面强酸中心或弱酸中心上进行有关。当加入少量正丁胺时,乙烯生成率增加,这与酸中心中毒后使积炭量减少有关。当正丁胺加入量增至一定值时,乙烯生成率逐渐下降。在不同反应温度(185,198,208℃)下测定了加入正丁胺后k值的变化,得到了各温度下被中毒活性中心数(N)和反应速率常数(K)之间的关系,并用正弦曲线方程进行了拟合,说明了催化剂表面活性的非均一性。用吡啶中毒也得到了相似的结果。同时,也得到了表现活化能随中毒中心数的变化曲线,并观察到补偿效应的存在。
The reaction of ethanol dehydration to ethylene on HZSM-5 catalyst was studied by means of micro-discontinuous flow catalytic chromatography. It was found that the reaction rate constant k is related to the reaction being centered on the strong acid sites or the weak acid sites on the catalyst surface. When a small amount of n-butylamine is added, the rate of ethylene production increases, which is related to the reduction of coke amount after acid poisoning. When the amount of n-butylamine increased to a certain value, ethylene production rate gradually decreased. The change of k value after the addition of n-butylamine was determined at different reaction temperatures (185, 198 and 208 ℃), and the relationship between the number of poisoning activity centers (N) and the reaction rate constant (K) at each temperature was obtained. Fitting was done to illustrate the heterogeneity of the catalyst surface activity. Similar results were obtained with pyridine poisoning. At the same time, the curve of activation energy with the number of poisoning centers was also obtained, and the existence of compensation effect was observed.