A series of catalysts were studied for the synthesis of diphenyl carbonate(DPC)by transesterification of dimethyl carbonate(DMC)with phenol.It was found that V-Cu oxide was the best catalyst among the tested catalysts...A series of catalysts were studied for the synthesis of diphenyl carbonate(DPC)by transesterification of dimethyl carbonate(DMC)with phenol.It was found that V-Cu oxide was the best catalyst among the tested catalysts.The effects of V-Cu amount,molar ratio of copper to vanadium,molar ratio of dimethyl carbonate to phenol and reaction time were investigated.Under the conditions of catalyst amount 3.1%(mass ratio to phenol),molar ratio of Cu/V of 1∶4,molar ratio of DMC/phenol of 1.5∶1 and a reaction time 9 h,the maximum conversion of phenol and total yields of methyl phenyl carbonate(MPC)and DPC were 41.9% and 40.3%,respectively.Reuse of the catalyst revealed that V-Cu oxide was a relatively stable catalyst.The activity of the catalyst after being reused four times reduced from 41.9% to 29.1%.Moreover,the deactivated catalyst was easily regenerated by calcination in air,and the catalytic activity of the regenerated catalyst was almost as high as that of the fresh sample,the phenol conversion was 39.8%.展开更多
The use of H2SO4‐,HCl‐,H3PO4‐,and CH3COOH‐activated montmorillonite(Mt)and WOx/H3PO4‐activated Mt as catalysts for the gas‐phase dehydration of glycerol was investigated.The WOx/H3PO4‐activated Mt catalysts wer...The use of H2SO4‐,HCl‐,H3PO4‐,and CH3COOH‐activated montmorillonite(Mt)and WOx/H3PO4‐activated Mt as catalysts for the gas‐phase dehydration of glycerol was investigated.The WOx/H3PO4‐activated Mt catalysts were prepared by an impregnation method using H3PO4‐activated Mt(Mt‐P)as the support.The catalysts were characterized using powder X‐ray diffraction,Fourier‐transform infrared spectroscopy,N2adsorption‐desorption,diffuse reflectance ultraviolet‐visible spectroscopy,temperature‐programmed desorption of NH3,and thermogravimetric analysis.The acid activation of Mt and WOx loaded on Mt‐P affected the strength and number of acid sites arising from H+exchange,the leaching of octahedral Al3+cations from Mt octahedral sheets,and the types of WOx(2.7≤x≤3)species(i.e.,isolated WO4/WO6‐containing clusters,two‐dimensional[WO6]polytungstates,or three‐dimensional WO3crystals).The strong acid sites were weakened,and the weak and medium acid sites were strengthened when the W loading on Mt‐P was12wt%(12%W/Mt‐P).The12%W/Mt‐P catalyst showed the highest catalytic activity.It gave a glycerol conversion of89.6%and an acrolein selectivity of81.8%at320°C.Coke deposition on the surface of the catalyst led to deactivation.展开更多
文摘A series of catalysts were studied for the synthesis of diphenyl carbonate(DPC)by transesterification of dimethyl carbonate(DMC)with phenol.It was found that V-Cu oxide was the best catalyst among the tested catalysts.The effects of V-Cu amount,molar ratio of copper to vanadium,molar ratio of dimethyl carbonate to phenol and reaction time were investigated.Under the conditions of catalyst amount 3.1%(mass ratio to phenol),molar ratio of Cu/V of 1∶4,molar ratio of DMC/phenol of 1.5∶1 and a reaction time 9 h,the maximum conversion of phenol and total yields of methyl phenyl carbonate(MPC)and DPC were 41.9% and 40.3%,respectively.Reuse of the catalyst revealed that V-Cu oxide was a relatively stable catalyst.The activity of the catalyst after being reused four times reduced from 41.9% to 29.1%.Moreover,the deactivated catalyst was easily regenerated by calcination in air,and the catalytic activity of the regenerated catalyst was almost as high as that of the fresh sample,the phenol conversion was 39.8%.
基金supported by the National Natural Science Foundation of China(21373185,41672033,21506188,21404090)the Open Project Programs of Engineering Research Center of Non-metallic Minerals of Zhejiang Province(ZD2015k07)+2 种基金of State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology(GCTKF2014006)of Key Laboratory of High Efficient Processing of Bamboo of Zhejiang Province(2016)of State Key Laboratory of Chemical Resource Engineering,Beijing University of Chemical Technology(CRE-2016-C-303)~~
文摘The use of H2SO4‐,HCl‐,H3PO4‐,and CH3COOH‐activated montmorillonite(Mt)and WOx/H3PO4‐activated Mt as catalysts for the gas‐phase dehydration of glycerol was investigated.The WOx/H3PO4‐activated Mt catalysts were prepared by an impregnation method using H3PO4‐activated Mt(Mt‐P)as the support.The catalysts were characterized using powder X‐ray diffraction,Fourier‐transform infrared spectroscopy,N2adsorption‐desorption,diffuse reflectance ultraviolet‐visible spectroscopy,temperature‐programmed desorption of NH3,and thermogravimetric analysis.The acid activation of Mt and WOx loaded on Mt‐P affected the strength and number of acid sites arising from H+exchange,the leaching of octahedral Al3+cations from Mt octahedral sheets,and the types of WOx(2.7≤x≤3)species(i.e.,isolated WO4/WO6‐containing clusters,two‐dimensional[WO6]polytungstates,or three‐dimensional WO3crystals).The strong acid sites were weakened,and the weak and medium acid sites were strengthened when the W loading on Mt‐P was12wt%(12%W/Mt‐P).The12%W/Mt‐P catalyst showed the highest catalytic activity.It gave a glycerol conversion of89.6%and an acrolein selectivity of81.8%at320°C.Coke deposition on the surface of the catalyst led to deactivation.
