Supported SBA-15 Catalyst For The Oxidation Of N-hexyl Alcohol, N-hexyl Aldehyde Synthesis Research

SBA-15mesoporous molecular sieves have larger surface area, ordered channel structure, adjustable pore diameter, In this work, we used impregnation method to prepare metal-doped SBA-15catalyst. The prepared catalysts were studied by characterization and green reactions under moderate condition. The catalysts were characterized through several technologies, such as XRD, FT-IR, BET, SEM, NH3-TPD, UV-vis. The catalyst properties and microscopic structure were studied comprehensively with corresponding explanation to its catalytic behavior. Moreover, the reaction conditions were optimized, including the dosing of catalyst, reaction temperature and reaction time. Further, the stability of the catalysts was studied with highly active catalyst under same reaction conditions.Al and Co modification SBA-15molecular materials were prepared by hydrothermal synthesis method. The microscopic analysis of catalyst used a series of characterization methods. The doping amount of metal and preparation conditions was investigated, and its influence on catalytic activity was studied. The results showed that the morphology, pore structure and acidity of mesoporous molecular sieve were influenced by several factors, including the doping amount of metal, hydrochloric acid concentration, crystallization temperature and calcination temperature. The study revealed that catalytic performance achieved its best at following condition:silica cobalt ratio was15, hydrochloric acid solution pH was1.5, crystallization temperature was120℃, calcination temperature was550℃. Under such circumstances, the conversion rate of hexanol was36.7%, the selectivity and the yield of hexanal was27.1%and9.9%, respectively.The metal loading catalyst was prepared by impregnation method. The catalysts were characterized and analyzed in order to select catalyst with high performance. The results showed that the conversion rate of hexanol was highest using Cr/Co-SBA-15as the catalyst, and the selectivity of hexanal was highest using Y/Co-SBA-15as the catalyst. Thus, the multi-metal loaded Co-SBA-15were studied examine the influence of Y2O3on Cr/Co-SBA-15structure and properties. Further, it showed that the type and load dosage of metal oxide have great influence on the catalytic performance. Proper amount of Y2O3can effectively improve the selectivity of prepared catalysts. When the load dosage of Y2O3was 1%, the catalyst exhibited the best performance for the reaction of catalytic oxidation of hexanol. Compared with4Cr/Co-SBA-15, its conversion rate of hexanol increased from43.7%to58.9%, the selectivity of hexanal increased from20.9%to42.3%.The reaction conditions of catalytic oxidation reaction were optimized, by study of following parameters:catalyst dosage, reaction temperature and reaction time. The result showed catalyst activity achieved its best at following conditions:catalyst dosage was0.4g, reaction temperature was130℃and reaction time was4h. In such conditions, the conversion of hexanol was up to62.8%, the selectivity and the yield of hexanal was up to51.1%and32.1%, respectively. After the catalyst was reused three times, catalytic activity decreased slightly. Kinetic analysis showed that activation energy of hexanol oxidization system using4Cr/lY/Co-SBA-15as catalyst is reduced greatly comparing with the catalytic dehydrogenation reaction.