ZSM-5/MgO质量比对复合催化剂物化性质及合成甲硫醇反应的影响
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摘要
采用介孔碱性MgO对微孔酸性ZSM-5分子筛进行复合改性,利用液相沉淀包覆技术制备了ZSM-5/MgO复合催化剂,研究了ZSM-5与MgO质量比对复合催化剂物化性质和合成甲硫醇催化性能的影响。采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、比表面积及孔隙分析仪(BET)和化学吸附分析仪(CO_2/NH_3-TPD)等手段对不同复合催化剂的晶相组成、微观形貌、孔结构及表面酸碱性进行分析表征。结果表明:ZSM-5/MgO质量比对ZSM-5/MgO复合催化剂的物化性质和催化性能影响较大。过高或过低ZSM-5/MgO质量比制得复合催化剂中MgO结晶度都有所降低,且未形成包覆相结构;ZSM-5/MgO质量比为1/3时制得复合催化剂形成了均匀包覆相结构和微-介孔结构(总比表面积为162 m~2/g,总孔体积0.46 cm~3/g),同时具有酸碱特性;在反应压力1.0 MPa、反应温度370℃、H_2S/CH_3OH摩尔比2/1、N_2流速80 mL/min、H_2S流速4.9 mL/min反应条件下合成甲硫醇,复合催化剂表现出优越的催化性能、稳定性及寿命,CH_3OH转化率、CH_3SH选择性和CH_3SH收率分别达到90.48%、90.04%和81.47%,催化剂寿命达到18 h。与单一ZSM-5分子筛相比,复合催化剂寿命延长了7 h,CH_3SH收率提高了13.97百分点。
ZSM-5/MgO composite catalysts were fabricated by using acidic microporous ZSM-5 molecular sieve and mesoporous alkaline MgO, based on liquid-phase precipitation coating route. The effect of mass ratio of ZSM-5 to MgO on the physicochemical properties and their catalytic performance in the synthesis of methanethiol was investigated. These obtained composite catalysts were extensively characterized by the X-ray diffractometer(XRD), scanning electron microscope(SEM), specific surface area and pore analyzer(BET) and chemisorption analyzer(CO_2/NH_3-TPD) techniques to investigate their crystalline property, morphology, pore structure and surface acidity-basicity, respectively. Results indicate that various mass ratios of ZSM-5 to MgO pose significant impact on the physicochemical properties and their catalytic performance. The crystallinity and content of MgO in composite catalyst is greatly affected by the ZSM-5/MgO mass ratio. As ZSM-5/MgO mass ratio of 1/3, the homogeneously continuous coating phase and hierarchical structure(total specific surface area of 162 m~2/g, the total pore volume of 0.46 cm~3/g) with acidity and basicity are successfully obtained, which exhibits excellent catalytic performances, stability and reaction lifetime, with methanol conversion of 90.48%, methanethiol selectivity of 90.04%, methanethiol yield of 81.47%, and catalyst lifetime of 18 h under the conditions of reaction pressure of 1.0 MPa, reaction temperature of 370 ℃, H_2S/CH_3OH molar ratio of 2/1, nitrogen flow rate of 80 mL/min and hydrogen sulfide flow rate of 4.9 mL/min. Compared with ZSM-5 molecular sieve, the reaction lifetime of the composite catalyst is extended by 7 h and the yield of methanethiol is increased by 13.97 percentage.
ZSM-5/MgO composite catalysts were fabricated by using acidic microporous ZSM-5 molecular sieve and mesoporous alkaline MgO, based on liquid-phase precipitation coating route. The effect of mass ratio of ZSM-5 to MgO on the physicochemical properties and their catalytic performance in the synthesis of methanethiol was investigated. These obtained composite catalysts were extensively characterized by the X-ray diffractometer(XRD), scanning electron microscope(SEM), specific surface area and pore analyzer(BET) and chemisorption analyzer(CO_2/NH_3-TPD) techniques to investigate their crystalline property, morphology, pore structure and surface acidity-basicity, respectively. Results indicate that various mass ratios of ZSM-5 to MgO pose significant impact on the physicochemical properties and their catalytic performance. The crystallinity and content of MgO in composite catalyst is greatly affected by the ZSM-5/MgO mass ratio. As ZSM-5/MgO mass ratio of 1/3, the homogeneously continuous coating phase and hierarchical structure(total specific surface area of 162 m~2/g, the total pore volume of 0.46 cm~3/g) with acidity and basicity are successfully obtained, which exhibits excellent catalytic performances, stability and reaction lifetime, with methanol conversion of 90.48%, methanethiol selectivity of 90.04%, methanethiol yield of 81.47%, and catalyst lifetime of 18 h under the conditions of reaction pressure of 1.0 MPa, reaction temperature of 370 ℃, H_2S/CH_3OH molar ratio of 2/1, nitrogen flow rate of 80 mL/min and hydrogen sulfide flow rate of 4.9 mL/min. Compared with ZSM-5 molecular sieve, the reaction lifetime of the composite catalyst is extended by 7 h and the yield of methanethiol is increased by 13.97 percentage.
引文
[1]ZIOLEK M,CZYZNIEWSKA J,LAMOTTE J,et al.Methanol adsorption and dehydration on alkali metal exchanged NaY zeolites[J].Catalysis Letters,1996,37(3/4):223-227.
[2]ZIOLEK M,CZYZNIEWSKA J,LAMOTTE J,et al.Reactions of alcohols with hydrogen sulfide on zeolites Part 6:FT,ir spectroscopy investigation of the reaction between methanol and hydrogen sulfide on NaX and NaY[J].Zeolites,1996,16(1):42-49.
[3]ZIOLEK M,CZYZNIEWSKA J,KUJAWA J,et al.Reactions of alcohols with hydrogen sulphide on zeolites Part 7:The effect of Br9nsted acidity of faujasite type zeolites on methanol hydrosulphurisation[J].Microporous&Mesoporous Materials,1998,23(1/2):45-54.
[4]ZIOLEK M,SOBCZAK I,NOWAK I,et al.Nbcontaining mesoporous molecular sieves-A possible application in the catalytic processes[J].Microporous&Mesoporous Materials,2000,35(2):195-207.
[5]MAUGE F,SAHIBEDDINE A,GAILLARD M,et al.Modification of the acidic properties of NaY Zeolite by H2S adsorption-An infrared study[J].Journal of Catalysis,2002,207(2):353-360.
[6]TREJDA M,KUJAWA J,ZIOLEK M.Iron modified MCM-41 materials characterised by methanol oxidation and sulphurisation reactions[J].Catalysis Letters,2006,108(3/4):141-146.
[7]TREJDA M,TUEL A,KUJAWA J,et al.Niobium rich SBA-15 materials-preparation,characterisation and catalytic activity[J].Microporous&Mesoporous Materials,2008,110(2):271-278.
[8]TREJDA M,WOJTASZEK A,ZIOLEK M,et al.Various hexagonally ordered mesoporous silicas as supports for chromium species-The effect of support on surface properties[J].Applied Catalysis A General,2009,365(1):135-140.
[9]REP M,PALOMARES A E,EDERMIRTH G,et al.Interaction of methanol with alkali metal exchanged molecular sieves 1IR spectroscopic study[J].Journal of Physical Chemistry B,2000,104(35):8624-8630.
[10]VAYSSILOV G N,LERCHER J A,ROSCH N.Interaction of methanol with alkali metal exchanged molecular sieves 2Density functional study[J].Journal of Physical Chemistry B,2000,104(35):8614-8623.
[11]刘洁翔,王延吉,董梅,等.硫醇分子在HMOR分子筛中吸附的量子化学研究[J].石油学报(石油加工),2007,23(6):61-65.(LIU Jiexiang,WANG Yanji,DONG Mei,et al.Quantum chemistry study on adsorption of thiols in HMOR zeolite[J].Acta Petrolei Sinica(Petroleum Processing Section),2007,23(6):61-65.)
[12]PLAISANCE C P,DOOLEY K M.Zeolite and metal oxide catalysts for the production of dimethyl sulfide and methanethiol[J].Catalysis Letters,2009,128(3/4):449-458.
[13]ZIOLEK M,KUJAWA J,SAUR O,et al.Metal oxides as catalysts for the reaction between methanol and hydrogen sulfide[J].Journal of Physical Chemistry,1993,97(38):9761-9766.
[14]ZIOLEK M,KUJAWA J,SAUR O,et al.Influence of hydrogen sulfide adsorption on the catalytic properties of metal oxides[J].Journal of Molecular Catalysis AChemical,1995,97(1):49-55.
[15]OLIVIERO L,LECLERC H,MANOILOVA O V,et al.Br9nsted acidity of MgO induced by H2Sadsorption[J].Industrial&Engineering Chemistry Research,2009,48(3):1237-1241.
[16]ZIOLEK M,KUJAWA J,CZYZNIEWSKA J,et al.Effect on the reaction between methanol and hydrogen sulphide of Na or Mo doping on zirconia and alumina[J].Applied Catalysis A General,1998,171(1):109-115.
[17]PASKACH T J,SCHRADER G L,MCCARLEY R E.Synthesis of methanethiol from methanol over reduced molybdenum sulfide catalysts based on the Mo6S8cluster[J].Journal of Catalysis,2015,211(2):285-295.
[18]NOWAK I,ZIOLEK M.Niobium compounds:Preparation,characterization,and application in heterogeneous catalysis[J].Chemical Reviews,2010,31(6):3603.
[19]CALVINO-CASILDA V,MARTIN-ARANDA R,SOBCZAK I,et al.Modification of acid-base properties of alkali metals containing catalysts by the application of various supports[J].Applied Catalysis A General,2006,303(1):121-130.
[20]ZHANG Y,CHEN S,WU M,et al.Promoting effect of SiO2 on the K2WO4/Al2O3 catalysts for methanethiol synthesis from methanol and H2S[J].Catalysis Communications,2012,22(18):48-51.
[21]MASHKINA A V.Heterogeneous catalytic synthesis of alkanethiols and dialkyl sulfides from alcohols and hydrogen sulfide[J].Russian Chemical Reviews,1995,64(12):1131-1147.
[22]CHOUDHARY V R,RANE V H,GADRE R V.Influence of precursors used in preparation of MgO on its surface properties and catalytic activity in oxidative coupling of methane[J].Journal of Catalysis,1994,145(2):300-311.
[23]ALMERINDO G I,PROBST L F D,CAMPOS C E M,et al.Magnesium oxide prepared via metal-chitosan complexation method:Application as catalyst for transesterification of soybean oil and catalyst deactivation studies[J].Journal of Power Sources,2011,196(19):8057-8063.
[24]ZHANG A,MA Q,WANG K,et al.Naphthenic acid removal from crude oil through catalytic decarboxylation on magnesium oxide[J].Applied Catalysis A General,2006,303(1):103-109.
[25]ELKHALIFA E A,FRIEDRICH H B.Magnesium oxide as a catalyst for the dehydrogenation of n-octane[J].Arabian Journal of Chemistry,2014,11(7):1154-1159.
[26]KHAN E A,HU E,LAI Z.Preparation of metal oxide/zeolite core-shell nanostructures[J].Microporous&Mesoporous Materials,2009,118(1):210-217.
[27]PANPA W,SUJARIDWORAKUN P,JINAWATH S.Photocatalytic activity of TiO2/ZSM-5composites in the presence of SO42-ion[J].Applied Catalysis B Environmental,2008,80(3):271-276.
[28]NIE R,LEI H,PAN S,et al.Core-shell structured CuO-ZnO@H-ZSM-5catalysts for CO hydrogenation to dimethyl ether[J].Fuel,2011,90(7):419-425.
[29]YANG G,TSUBAKI N,SHAMOTO J,et al.Confinement effect and synergistic function of H-ZSM-5/Cu-ZnO-Al2O3capsule catalyst for one-step controlled synthesis[J].Journal of the American Chemical Society,2010,132(23):8129-8136.
[30]张海荣,张卿,李玉平,等.以SAPO-34为原料直接合成小晶粒PZSM-5及其甲醇转化催化性能[J].石油学报(石油加工),2010,26(3):357-363.(ZHANGHairong,ZHANG Qing,LI Yuping,et al.Direct synthesis of small crystal PZSM-5from SAPO-34and its catalytic performance for methanol conversion[J].Acta Petrolei Sinica(Petroleum Processing Section),2010,26(3):357-363.)
[31]DUAN C,ZHANG X,ZHOU R,et al.Comparative studies of ethanol to propylene over HZSM-5/SAPO-34catalysts prepared by hydrothermal synthesis and physical mixture[J].Fuel Processing Technology,2013,108(7):31-40.
[32]RAZAVIAN M,FATEMI S.Synthesis and application of ZSM-5/SAPO-34 and SAPO-34/ZSM-5 composite systems for propylene yield enhancement in propane dehydrogenation process[J].Microporous&Mesoporous Materials,2015,201(19):176-189.
[33]薛建伟,吴岚,吕志平,等.F-ZSM-5沸石的合成及对偏三甲苯-甲醇烷基化制均四甲苯的催化性能研究[J].燃料化学学报,2000,28(1):16-19.(XUE Jianwei,WU Lan,LZhiping,et al.Synthesis of F-ZSM-5zeolite and its catalytic performance for alkylation of trimethylbenzene-methanol to durene[J].Journal of Fuel Chemistry and Technology,2000,28(1):16-19.)
[34]周琦,贾建刚,赵红顺,等.真空熔炼制备Fe3(Si(1-x),Alx)金属间化合物及其有序度研究[C]//长沙:中国功能材料及其应用学术会议,2010:236-239.
[2]ZIOLEK M,CZYZNIEWSKA J,LAMOTTE J,et al.Reactions of alcohols with hydrogen sulfide on zeolites Part 6:FT,ir spectroscopy investigation of the reaction between methanol and hydrogen sulfide on NaX and NaY[J].Zeolites,1996,16(1):42-49.
[3]ZIOLEK M,CZYZNIEWSKA J,KUJAWA J,et al.Reactions of alcohols with hydrogen sulphide on zeolites Part 7:The effect of Br9nsted acidity of faujasite type zeolites on methanol hydrosulphurisation[J].Microporous&Mesoporous Materials,1998,23(1/2):45-54.
[4]ZIOLEK M,SOBCZAK I,NOWAK I,et al.Nbcontaining mesoporous molecular sieves-A possible application in the catalytic processes[J].Microporous&Mesoporous Materials,2000,35(2):195-207.
[5]MAUGE F,SAHIBEDDINE A,GAILLARD M,et al.Modification of the acidic properties of NaY Zeolite by H2S adsorption-An infrared study[J].Journal of Catalysis,2002,207(2):353-360.
[6]TREJDA M,KUJAWA J,ZIOLEK M.Iron modified MCM-41 materials characterised by methanol oxidation and sulphurisation reactions[J].Catalysis Letters,2006,108(3/4):141-146.
[7]TREJDA M,TUEL A,KUJAWA J,et al.Niobium rich SBA-15 materials-preparation,characterisation and catalytic activity[J].Microporous&Mesoporous Materials,2008,110(2):271-278.
[8]TREJDA M,WOJTASZEK A,ZIOLEK M,et al.Various hexagonally ordered mesoporous silicas as supports for chromium species-The effect of support on surface properties[J].Applied Catalysis A General,2009,365(1):135-140.
[9]REP M,PALOMARES A E,EDERMIRTH G,et al.Interaction of methanol with alkali metal exchanged molecular sieves 1IR spectroscopic study[J].Journal of Physical Chemistry B,2000,104(35):8624-8630.
[10]VAYSSILOV G N,LERCHER J A,ROSCH N.Interaction of methanol with alkali metal exchanged molecular sieves 2Density functional study[J].Journal of Physical Chemistry B,2000,104(35):8614-8623.
[11]刘洁翔,王延吉,董梅,等.硫醇分子在HMOR分子筛中吸附的量子化学研究[J].石油学报(石油加工),2007,23(6):61-65.(LIU Jiexiang,WANG Yanji,DONG Mei,et al.Quantum chemistry study on adsorption of thiols in HMOR zeolite[J].Acta Petrolei Sinica(Petroleum Processing Section),2007,23(6):61-65.)
[12]PLAISANCE C P,DOOLEY K M.Zeolite and metal oxide catalysts for the production of dimethyl sulfide and methanethiol[J].Catalysis Letters,2009,128(3/4):449-458.
[13]ZIOLEK M,KUJAWA J,SAUR O,et al.Metal oxides as catalysts for the reaction between methanol and hydrogen sulfide[J].Journal of Physical Chemistry,1993,97(38):9761-9766.
[14]ZIOLEK M,KUJAWA J,SAUR O,et al.Influence of hydrogen sulfide adsorption on the catalytic properties of metal oxides[J].Journal of Molecular Catalysis AChemical,1995,97(1):49-55.
[15]OLIVIERO L,LECLERC H,MANOILOVA O V,et al.Br9nsted acidity of MgO induced by H2Sadsorption[J].Industrial&Engineering Chemistry Research,2009,48(3):1237-1241.
[16]ZIOLEK M,KUJAWA J,CZYZNIEWSKA J,et al.Effect on the reaction between methanol and hydrogen sulphide of Na or Mo doping on zirconia and alumina[J].Applied Catalysis A General,1998,171(1):109-115.
[17]PASKACH T J,SCHRADER G L,MCCARLEY R E.Synthesis of methanethiol from methanol over reduced molybdenum sulfide catalysts based on the Mo6S8cluster[J].Journal of Catalysis,2015,211(2):285-295.
[18]NOWAK I,ZIOLEK M.Niobium compounds:Preparation,characterization,and application in heterogeneous catalysis[J].Chemical Reviews,2010,31(6):3603.
[19]CALVINO-CASILDA V,MARTIN-ARANDA R,SOBCZAK I,et al.Modification of acid-base properties of alkali metals containing catalysts by the application of various supports[J].Applied Catalysis A General,2006,303(1):121-130.
[20]ZHANG Y,CHEN S,WU M,et al.Promoting effect of SiO2 on the K2WO4/Al2O3 catalysts for methanethiol synthesis from methanol and H2S[J].Catalysis Communications,2012,22(18):48-51.
[21]MASHKINA A V.Heterogeneous catalytic synthesis of alkanethiols and dialkyl sulfides from alcohols and hydrogen sulfide[J].Russian Chemical Reviews,1995,64(12):1131-1147.
[22]CHOUDHARY V R,RANE V H,GADRE R V.Influence of precursors used in preparation of MgO on its surface properties and catalytic activity in oxidative coupling of methane[J].Journal of Catalysis,1994,145(2):300-311.
[23]ALMERINDO G I,PROBST L F D,CAMPOS C E M,et al.Magnesium oxide prepared via metal-chitosan complexation method:Application as catalyst for transesterification of soybean oil and catalyst deactivation studies[J].Journal of Power Sources,2011,196(19):8057-8063.
[24]ZHANG A,MA Q,WANG K,et al.Naphthenic acid removal from crude oil through catalytic decarboxylation on magnesium oxide[J].Applied Catalysis A General,2006,303(1):103-109.
[25]ELKHALIFA E A,FRIEDRICH H B.Magnesium oxide as a catalyst for the dehydrogenation of n-octane[J].Arabian Journal of Chemistry,2014,11(7):1154-1159.
[26]KHAN E A,HU E,LAI Z.Preparation of metal oxide/zeolite core-shell nanostructures[J].Microporous&Mesoporous Materials,2009,118(1):210-217.
[27]PANPA W,SUJARIDWORAKUN P,JINAWATH S.Photocatalytic activity of TiO2/ZSM-5composites in the presence of SO42-ion[J].Applied Catalysis B Environmental,2008,80(3):271-276.
[28]NIE R,LEI H,PAN S,et al.Core-shell structured CuO-ZnO@H-ZSM-5catalysts for CO hydrogenation to dimethyl ether[J].Fuel,2011,90(7):419-425.
[29]YANG G,TSUBAKI N,SHAMOTO J,et al.Confinement effect and synergistic function of H-ZSM-5/Cu-ZnO-Al2O3capsule catalyst for one-step controlled synthesis[J].Journal of the American Chemical Society,2010,132(23):8129-8136.
[30]张海荣,张卿,李玉平,等.以SAPO-34为原料直接合成小晶粒PZSM-5及其甲醇转化催化性能[J].石油学报(石油加工),2010,26(3):357-363.(ZHANGHairong,ZHANG Qing,LI Yuping,et al.Direct synthesis of small crystal PZSM-5from SAPO-34and its catalytic performance for methanol conversion[J].Acta Petrolei Sinica(Petroleum Processing Section),2010,26(3):357-363.)
[31]DUAN C,ZHANG X,ZHOU R,et al.Comparative studies of ethanol to propylene over HZSM-5/SAPO-34catalysts prepared by hydrothermal synthesis and physical mixture[J].Fuel Processing Technology,2013,108(7):31-40.
[32]RAZAVIAN M,FATEMI S.Synthesis and application of ZSM-5/SAPO-34 and SAPO-34/ZSM-5 composite systems for propylene yield enhancement in propane dehydrogenation process[J].Microporous&Mesoporous Materials,2015,201(19):176-189.
[33]薛建伟,吴岚,吕志平,等.F-ZSM-5沸石的合成及对偏三甲苯-甲醇烷基化制均四甲苯的催化性能研究[J].燃料化学学报,2000,28(1):16-19.(XUE Jianwei,WU Lan,LZhiping,et al.Synthesis of F-ZSM-5zeolite and its catalytic performance for alkylation of trimethylbenzene-methanol to durene[J].Journal of Fuel Chemistry and Technology,2000,28(1):16-19.)
[34]周琦,贾建刚,赵红顺,等.真空熔炼制备Fe3(Si(1-x),Alx)金属间化合物及其有序度研究[C]//长沙:中国功能材料及其应用学术会议,2010:236-239.
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