摘要
利用吡啶吸附红外光谱(Py-IR)和X射线衍射法表征了磷钨酸(PW)、氢氧化铌改性分子筛的表面酸性和结构,用催化法脱除芳烃中微量烯烃的烷基化反应研究其酸催化性质。结果表明:催化剂的结构、表面酸含量和磷钨酸、氢氧化铌在催化剂中所占的比例,都显著地影响烷基化反应;Dawson结构的磷钨酸比Kiggen结构的磷钨酸具有较好的催化烷基化反应活性;随着磷钨酸含量的增加,催化剂B酸量先增加后减少,L酸量减少;随着氢氧化铌含量的增加,总B酸量和L酸量都减少,催化剂的活性随总B酸量与总L酸量比值的增加而提高;用磷酸或草酸处理氢氧化铌,总B酸量与总L酸量的比值增大,可进一步提高分子筛的活性和寿命。研究结果还表明:强B酸不利于脱烯烃反应。
FT-IR and XRD were used to investigate the surface acidity and the structure of Y-zeolite modified by phosphatotungstic acid and Nb（OH）5, and the catalytic activity was determined by removing of trace olefins from aromatic hydrocarbons. The results showed that the structure of catalysts, surface acidity and the proportion of the phosphatotungstic acid and Nb（OH）5 in catalysts would greatly affect the alkylation reaction. The catalytic activity of Dawson structure phosphatotungstic acid was much higher than that of Kiggen structure. B acid content increased first and then decreased while L acid content increased with the weight percent of niobium. Acid site number decreased with the weight percent of niobium and the activity of catalysts increased with the ratio of total B acid to total L acid. Treating Nb（OH）5 with H3PO4 or H2C2O5 would increase the ratio of total B acid to total L acid, and thus increase the activity and life span of the molecular. The results also revealed that the strong B acid was not helpful to remove trace olefins from aromatic hydrocarbons.
出处
《华东理工大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2008年第5期635-640,共6页
Journal of East China University of Science and Technology
作者简介
曾拥军（1983-），男，江西人，硕士研究生，研究方向为石油化工与工业催化。
通讯联系人：施力，E-mail：yyshi@ecust．edu．cn
