Study of catalyst deactivation during 1,3-butanediol dehydration to produce butadiene
Study of catalyst deactivation during 1,3-butanediol dehydration to produce butadiene
复制标题
1,3-丁二醇脱水制丁二烯催化剂失活研究
DOI：
10.1016/j.micromeso.2021.111066
复制
发表时间：
2021
影响因子：
5.2
通讯作者：
C. Padró
中科院分区：
文献类型：
--
作者：
Andrea C. Rodríguez;M. E. Sad;H. Cruchade;L. Pinard;C. Padró
用不同性质的固体酸：Al_2O_3、SiO_2/Al_2O_3、HZSM5和负载在SiO_2上的磷钨杂多酸(TPA)研究了1，3-丁二醇气相脱水过程中催化剂的失活和结焦机理。用N2物理吸附、FTIR光谱、吸附吡啶的FTIR、DSC-TGA、GC-MS和MALDI-TOF MS(基质辅助激光解吸/电离飞行时间质谱仪)等技术对失活催化剂进行了表征。废、洗(CH2Cl2直接萃取)样品和表面可溶焦的MALDI-TOF MS表征结果表明，不同催化剂上生成的焦炭性质不同，HZSM5和TPA/SiO_2上的炭质产物比Al_2O_3和SiO_2/Al_2O_3上的炭质产物高。催化剂经氢氟酸溶解和CH2Cl2萃取后，对总焦炭和不溶焦进行了分析。不溶性焦炭只在TPA/SiO_2上检测到，这是由于其Brnsted酸中心的强度造成的。总可溶焦的GC-MS色谱图表明，在HZSM5的情况下，芳香族和多聚体物种的存在是非常烷基化的。特别是，HZSM5上的焦炭具有很好的差异性，包括烷基那夫塔烯和烷基芳烃，这表明焦炭的形成是通过择形机理实现的。
Catalyst deactivation and mechanism of coke formation during the gas phase dehydration of 1,3-butanediol were studied on solid acids of different nature: Al2O3, SiO2/Al2O3, HZSM5 and tungstophosphoric acid (TPA) supported on SiO2. All the catalysts deactivated on stream with a significant coke content ranged between 9% and 14% C. Fresh and spent catalysts as well as carbonaceous deposits were thoroughly characterized using different techniques such as N2physisorption, FTIR spectroscopy, FTIR of adsorbed pyridine, DSC-TGA, GC-MS and MALDI-TOF MS (matrix-assisted laser desorption/ionization time of flight mass spectrometry). The IR spectra of spent and washed (after direct extraction with CH2Cl2) samples and the superficial soluble coke characterized by MALDI-TOF MS showed the different nature of coke formed in each catalyst with carbonaceous products of higher molecular weights on HZSM5 and TPA/SiO2than on Al2O3and SiO2/Al2O3. After catalyst dissolution using hydrofluoric acid and extraction with CH2Cl2both total soluble and insoluble coke were analyzed. Insoluble coke was only detected on TPA/SiO2and it was attributed to the strength of its Brønsted acid sites. GC-MS chromatograms of total soluble coke showed the presence of aromatic and polyromantic species, that were very alkylated in the case of HZSM5. Particularly, the well differentiated nature of coke on HZSM5 including alkylnaftalenes and alkylantracenes suggested the coke formation by a shape selectivity mechanism.