硝酸处理活性炭对醋酸乙烯催化活性的影响

Effect of HNO_3 Treated Activated Carbon on Its Catalytic Activity for Vinyl Acetate Synthesis

研究了改性活性炭载体的表面物理化学性质及其对乙炔法合成醋酸乙烯催化剂催化性能的影响。研究发现,催化剂中醋酸锌的负载量基本相同时,经质量分数15％硝酸处理的活性炭为载体制得的催化剂比未经处理的活性炭为载体制得的催化剂的活性相对提高5.36％。硝酸氧化可显著提高活性炭的含氧官能团的量,增加中、大孔的比表面积和孔体积,影响催化剂的活性。活性炭中的中、大孔对催化剂活性有利,但含氧官能团的影响更为强烈,催化活性与活性炭载体的内酯基含量呈正相关,与羟基含量呈负相关。并对反应机理进行了推测。

Effects of surface characteristic of treated activated carbon on catalyst for vinyl acetate synthesis from acetylene and acetic acid were studied. Both structure and catalytic performance were improved when activated carbons were treated with dilute HNO3. When mass fraction of HNO3 was 15% ,activity of the catalyst was5.36% higher than that of activated carbon without being treated. Surface area of macro-and mesopores increased after treatment. Amount of oxygen - containing groups in activated carbon was considerably increased by HNO3 oxidation. Catalytic activity was improved along with amount of lactonic groups, but the increasing of hydroxy groups on the contrary inhibited the reaction. In comparing with effects of texture on catalytic activity, those of oxygen-containing groups were more prominent. The reaction mechanism was proposed.