摘要
煤焦油中苯酚的高效定向转化制备精细化学品对于煤炭的高值化利用具有重要意义。采用共沉淀法经改变晶化时间制备出一系列镁铝水滑石样品,通过XRD、ICP-OES、TG、SEM、CO_(2)-TPD和NH_(3)-TPD等手段对水滑石及其焙烧产物进行表征,并考察了焙烧水滑石对苯酚与碳酸二甲酯经O-烷基化合成苯甲醚的反应的催化性能。结果表明,随晶化时间延长,镁铝水滑石的晶粒尺寸在a轴和c轴方向均逐渐增加,样品颗粒为片层结构的球形聚集体,颗粒尺寸逐渐增大,孔容和平均孔径逐渐增加,催化剂表面的弱碱量、弱酸量和强酸量均呈增加趋势而强碱量逐渐减少,强酸与强碱之比逐渐增大。在325℃、WHSV为2 h^(-1)下对物质的量比为1∶3的苯酚和碳酸二甲酯混合溶液在固定床中进行气相反应,所有催化剂对苯酚的转化率均在95%以上,苯甲醚的选择性随晶化时间的延长而逐渐提高,晶化时间为12 h所制备的镁铝水滑石样品作为催化剂时,苯酚的转化率为97.91%,苯甲醚的选择性为91.33%。
The efficient selective conversion of phenol from coal tar to fine chemicals is important to the high-value utilization of coal.A series of MgAl hydrotalcite was prepared using co-precipitation method by changing crystallization time.MgAl hydrotalcite and its calcined products were characterized by XRD,ICP-OES,TG,SEM,CO_(2)-TPD and NH_(3)-TPD,and the catalytic performance of the calcined products for O-alkylation of phenol by dimethyl carbonate(DMC)to anisole were investigated.The results show that with the extension of crystallization time,the crystal size of hydrotalcite in both the a-axis and c-axis are increased,the particles are spherical clusters of plates and are increased with crystallization time,the pore volume and mean diameter are also increased.The weak bases,weak acids and strong acids are all increased while the strong bases are reduced.When phenol and DMC mixture(1∶3 mol ratio)was reacted on fixed bed reactor in gas phase at 325℃and WHSV=2 h^(-1),the conversion of phenol is over 95%over all catalyst,and the selectivity of anisole is increased with crystallization time.The conversion of phenol is 97.91%,and the selectivity of anisole is 91.33%over the catalyst prepared with 12 h crystallization time.
作者
张海永
李杰
麦丽婵
郭瑾
祁婷婷
张世纪
王永刚
ZHANG Haiyong;LI Jie;MAI Lichan;GUO Jin;QI Tingting;ZHANG Shiji;WANG Yonggang(School of Chemical&Environmental Engineering,China University of Mining&Technology-Beijing,Beijing 100083,China;Institute of Chemistry,Chinese Academy of Sciences,Beijing 100190,China)
出处
《洁净煤技术》
CAS
CSCD
北大核心
2024年第S02期176-181,共6页
Clean Coal Technology
基金
国家自然科学基金资助项目(21506251)
大学生创新训练资助项目(202203001)
关键词
镁铝水滑石
晶化时间
晶粒尺寸
苯酚
苯甲醚
MgAl hydrotalcite
crystallization time
grain size
phenol
anisole
