Biodiesel was synthesized from soybean oil by transesterification over Li_2SiO_3 catalyst.The Li_2SiO_3 can be used for biodiesel production directly without further drying or thermal pretreatment,no obvious differenc...Biodiesel was synthesized from soybean oil by transesterification over Li_2SiO_3 catalyst.The Li_2SiO_3 can be used for biodiesel production directly without further drying or thermal pretreatment,no obvious difference in the FAME conversion（92.4-96.7%） between the air-exposed catalyst（24-72 h） and the fresh one（94.2%）.This leads to important benefits when considering industrial applications of Li_2SiO_3 as a solid catalyst for storing and handling catalyst without taking special actions.展开更多
Tungstated zirconia(WO_(3)/ZrO_(2))solid acid catalysts with different WO_(3) contents were prepared by a hydrothermal method and then used in the catalytic aquathermolysis of heavy oil from Xinjiang.The WO_(3)/ZrO_(2...Tungstated zirconia(WO_(3)/ZrO_(2))solid acid catalysts with different WO_(3) contents were prepared by a hydrothermal method and then used in the catalytic aquathermolysis of heavy oil from Xinjiang.The WO_(3)/ZrO_(2) solid acid catalyst was characterized by a range of characterization methods,including X-ray diffraction,NH3-temperature programmed desorption,and pyridine infrared spectroscopy.The WO_(3) content of the WO_(3)/ZrO_(2) catalysts had an important impact on the structure and property of the catalysts.When the WO_(3) mass fraction was 20%,it facilitated the formation of tetragonal zirconia,thereby enhancing the creation of robust acidic sites.Acidity is considered to have a strong impact on the catalytic performance of the aquathermolysis of heavy oil.When the catalyst containing 20%WO_(3) was used to catalyze the aquathermolysis of heavy oil under conditions of 14.5 MPa,340℃,and 24 h,the viscosity of heavy oil decreased from 47266 to 5398 mPa·s and the viscosity reduction rate reached 88.6%.The physicochemical properties of heavy oil before and after the aquathermolysis were analyzed using a saturates,aromatics,resins,and asphaltenes analysis,gas chromatography,elemental analysis,densimeter etc.After the aquathermolysis,the saturate and aromatic contents significantly increased from 43.3%to 48.35%and 19.47%to 21.88%,respectively,with large reductions in the content of resin and asphaltene from 28.22%to 25.06%and 5.36%to 2.03%,respectively.The sulfur and nitrogen contents,and the density of the oil were significantly decreased.These factors were likely the main reasons for promoting the viscosity reduction of heavy oil during the aquathermolysis over the WO_(3)/ZrO_(2) solid acid catalysts.展开更多
A nanoporous MoO3/ZrO2 mixed oxide was hydrothermally synthesized by hydrolyzing zirconium isopropoxide in the presence of a cationic surfactant, eetyltrimethylammonium bromide（CTAB）. The crystal structure and the a...A nanoporous MoO3/ZrO2 mixed oxide was hydrothermally synthesized by hydrolyzing zirconium isopropoxide in the presence of a cationic surfactant, eetyltrimethylammonium bromide（CTAB）. The crystal structure and the acidity of the obtained nanoporous MoO3/ZrO2 mixed oxide were determined by means of XRD, N2 adsorption-desorption and NH3-TPD, respectively. The isobutane/butene alkylation over the MoO3/ZrO2 catalyst was carried out in a fixed bed reactor. The results reveal that ZrO2 in MoO3/ZrO2 exists mainly in the tetragonal phase, and the catalyst samples possess large specific surface areas as well as moderate acidity for isobutane/butene alkylation. Compared with samples prepared by impregnation and sol-gel processes, MoO3/ZrO2 mixed oxide samples prepared in this work have a better catalytic activity.展开更多
Solid acid MoO_(3)/ZrO_(2)-TiO_(2)catalysts were prepared by impregnation method,and catalytic hydrolysis of difluorodichloromethane(CFC-12)over the catalyst was studied.The presence of MoO_(3)/ZrO_(2)-TiO_(2)catalyst...Solid acid MoO_(3)/ZrO_(2)-TiO_(2)catalysts were prepared by impregnation method,and catalytic hydrolysis of difluorodichloromethane(CFC-12)over the catalyst was studied.The presence of MoO_(3)/ZrO_(2)-TiO_(2)catalyst in polycrystalline state could be clearly observed by transmission electron microscopy(TEM).Mesopores were detected by N2 adsorption-desorption isotherms which further confirmed the MoO_(3)/ZrO_(2)-TiO_(2)structural characteristics of catalyst.The results of NH_(3)-TPD showed that the calcination temperatures had a great influence on the acidity of the catalyst,and the weak acidic site had a strong catalytic activity for the catalytic hydrolysis of CFC-12.Moreover,ZrO_(2)-TiO_(2)was highly dispersed in the MoO_(3)framework,suggested by powder X-ray diffraction(XRD)and N_(2)adsorption-desorption results.The effects of the catalyst calcination temperatures on the conversion rate of CFC-12 were studied.The effects of catalytic hydrolysis temperatures and water vapor concentration on the catalytic hydrolysis rate of CFC-12 were also studied.The solid acid MoO_(3)/ZrO_(2)-TiO_(2)was calcined at 500℃for 3 h at a catalytic hydrolysis temperature of 400℃and water vapor concentration of 83.18%,and catalytic hydrolysis rate of CFC-12 reached 98.65%.The hydrolysis rate of CFC-12 remained above 65.34%after 30 hours continuous reaction.展开更多
文摘Biodiesel was synthesized from soybean oil by transesterification over Li_2SiO_3 catalyst.The Li_2SiO_3 can be used for biodiesel production directly without further drying or thermal pretreatment,no obvious difference in the FAME conversion（92.4-96.7%） between the air-exposed catalyst（24-72 h） and the fresh one（94.2%）.This leads to important benefits when considering industrial applications of Li_2SiO_3 as a solid catalyst for storing and handling catalyst without taking special actions.
基金the financial support from the Open Fund Project of the National Oil Shale Exploitation Research and Development Center,China(No.33550000-22-ZC0613-0255)the Graduate Student Innovation and Practical Ability Training Program of Xi’an Shiyou University(No.YCS23213098)+3 种基金the National Natural Science Foundation of China(No.52274039)the Natural Science Basic Research Plan in Shaanxi Province of China(Program No.2024JC-YBMS-085)the CNPC Innovation Found(No.2022DQ02-0402)The authors also thank the Modern Analysis and Test Center of Xi’an Shiyou University for their help with the characterization of catalysts and analysis of products.
文摘Tungstated zirconia(WO_(3)/ZrO_(2))solid acid catalysts with different WO_(3) contents were prepared by a hydrothermal method and then used in the catalytic aquathermolysis of heavy oil from Xinjiang.The WO_(3)/ZrO_(2) solid acid catalyst was characterized by a range of characterization methods,including X-ray diffraction,NH3-temperature programmed desorption,and pyridine infrared spectroscopy.The WO_(3) content of the WO_(3)/ZrO_(2) catalysts had an important impact on the structure and property of the catalysts.When the WO_(3) mass fraction was 20%,it facilitated the formation of tetragonal zirconia,thereby enhancing the creation of robust acidic sites.Acidity is considered to have a strong impact on the catalytic performance of the aquathermolysis of heavy oil.When the catalyst containing 20%WO_(3) was used to catalyze the aquathermolysis of heavy oil under conditions of 14.5 MPa,340℃,and 24 h,the viscosity of heavy oil decreased from 47266 to 5398 mPa·s and the viscosity reduction rate reached 88.6%.The physicochemical properties of heavy oil before and after the aquathermolysis were analyzed using a saturates,aromatics,resins,and asphaltenes analysis,gas chromatography,elemental analysis,densimeter etc.After the aquathermolysis,the saturate and aromatic contents significantly increased from 43.3%to 48.35%and 19.47%to 21.88%,respectively,with large reductions in the content of resin and asphaltene from 28.22%to 25.06%and 5.36%to 2.03%,respectively.The sulfur and nitrogen contents,and the density of the oil were significantly decreased.These factors were likely the main reasons for promoting the viscosity reduction of heavy oil during the aquathermolysis over the WO_(3)/ZrO_(2) solid acid catalysts.
文摘A nanoporous MoO3/ZrO2 mixed oxide was hydrothermally synthesized by hydrolyzing zirconium isopropoxide in the presence of a cationic surfactant, eetyltrimethylammonium bromide（CTAB）. The crystal structure and the acidity of the obtained nanoporous MoO3/ZrO2 mixed oxide were determined by means of XRD, N2 adsorption-desorption and NH3-TPD, respectively. The isobutane/butene alkylation over the MoO3/ZrO2 catalyst was carried out in a fixed bed reactor. The results reveal that ZrO2 in MoO3/ZrO2 exists mainly in the tetragonal phase, and the catalyst samples possess large specific surface areas as well as moderate acidity for isobutane/butene alkylation. Compared with samples prepared by impregnation and sol-gel processes, MoO3/ZrO2 mixed oxide samples prepared in this work have a better catalytic activity.
基金Funded by the National Natural Science Foundation of China(No.51568068)the Young and Middle-aged Academic and Technical Leaders Reserve Talent Program(No.202105AC160054)。
文摘Solid acid MoO_(3)/ZrO_(2)-TiO_(2)catalysts were prepared by impregnation method,and catalytic hydrolysis of difluorodichloromethane(CFC-12)over the catalyst was studied.The presence of MoO_(3)/ZrO_(2)-TiO_(2)catalyst in polycrystalline state could be clearly observed by transmission electron microscopy(TEM).Mesopores were detected by N2 adsorption-desorption isotherms which further confirmed the MoO_(3)/ZrO_(2)-TiO_(2)structural characteristics of catalyst.The results of NH_(3)-TPD showed that the calcination temperatures had a great influence on the acidity of the catalyst,and the weak acidic site had a strong catalytic activity for the catalytic hydrolysis of CFC-12.Moreover,ZrO_(2)-TiO_(2)was highly dispersed in the MoO_(3)framework,suggested by powder X-ray diffraction(XRD)and N_(2)adsorption-desorption results.The effects of the catalyst calcination temperatures on the conversion rate of CFC-12 were studied.The effects of catalytic hydrolysis temperatures and water vapor concentration on the catalytic hydrolysis rate of CFC-12 were also studied.The solid acid MoO_(3)/ZrO_(2)-TiO_(2)was calcined at 500℃for 3 h at a catalytic hydrolysis temperature of 400℃and water vapor concentration of 83.18%,and catalytic hydrolysis rate of CFC-12 reached 98.65%.The hydrolysis rate of CFC-12 remained above 65.34%after 30 hours continuous reaction.
