以(NH_(4))_(6)Mo_(7)O_(24)·4H_(2)O、Bi(NO_(3))_(3)·5H_(2)O、Fe(NO_(3))_(3)·9H_(2)O、Co(NO_(3))_(2)·6H_(2)O和KNO_(3)为前驱体金属盐,通过共沉淀法制备了一系列MoBiFeCoK混合氧化物催化剂,考察了主金属Mo、...以(NH_(4))_(6)Mo_(7)O_(24)·4H_(2)O、Bi(NO_(3))_(3)·5H_(2)O、Fe(NO_(3))_(3)·9H_(2)O、Co(NO_(3))_(2)·6H_(2)O和KNO_(3)为前驱体金属盐,通过共沉淀法制备了一系列MoBiFeCoK混合氧化物催化剂,考察了主金属Mo、Bi,助金属Fe、Co和掺杂金属K含量对催化剂催化异丁烯气相氧化反应的影响,通过SEM、EDX、XRD、NH_(3)-TPD对掺杂K前后的催化剂进行了表征,同时对催化异丁烯气相氧化反应条件进行了优化,并测试其100 h的催化稳定性。结果表明,Bi、Fe、Co和K的含量对MoBiFeCoK混合氧化物催化剂催化异丁烯气相氧化反应的性能有显著影响,其中,Mo_(12)Bi_(1.2)Fe_(3)Co_(8)K_(0.4)表现出最优催化性能;K的掺杂降低了催化剂酸量(从Mo12Bi1.2Fe3Co8的15.27μmol/g降至Mo_(12)Bi_(1.2)Fe_(3)Co_(8)K_(0.4)的5.91μmol/g),并明显提升主产物甲基丙烯醛(MAL)的选择性;异丁烯气相氧化反应的最佳条件为:以0.66 g Mo_(12)Bi_(1.2)Fe_(3)Co_(8)K_(0.4)为催化剂,反应温度320℃,n(O_(2))∶n(异丁烯)(氧烯比)=10∶1,体积空速(GHSV)=2000h^(-1)。在该条件下,Mo_(12)Bi_(1.2)Fe_(3)Co_(8)K_(0.4)在100h的催化异丁烯气相氧化反应中表现稳定,异丁烯转化率保持在98.6%,MAL选择性保持在86.4%。展开更多
Ionic liquid（IL）,[bmim]PF6,was used in the reaction of one-step oxidative esterification from methacrolein to methyl methacrylate. It was found that ionic liquid not only increased the selectivity of methyl methacry...Ionic liquid（IL）,[bmim]PF6,was used in the reaction of one-step oxidative esterification from methacrolein to methyl methacrylate. It was found that ionic liquid not only increased the selectivity of methyl methacrylate but also inhibited its polymerization. The selectivity of methyl methacrylate was increased from 45% to 100% with ionic liquid. The experiment results showed that the content of ionic liquid had no effects on the selectivity of methyl methacrylate in a certain range of IL concentration,which indicated that ionic liquid could be used as a potential inhibitor of polymerization. [WT5HZ]展开更多
Supported multi-metal catalyst was prepared by impregnation.A variety of factors such as reaction temperature, feedstock ratio, alkali concentration, catalyst concentration and antipolymerizer concentration were syste...Supported multi-metal catalyst was prepared by impregnation.A variety of factors such as reaction temperature, feedstock ratio, alkali concentration, catalyst concentration and antipolymerizer concentration were systematically investigated in terms of their effects on the oxidative esterification reaction for methyl methacrylate production from methacrolein.The experimental results showed that under the condition of temperature 333 K,methanol/methacrolein ratio 97∶1(molar ratio),NaOH concentration 0.001 g·ml^-1 and catalyst concentration 0.02 g·ml^-1, methacrolein conversion and methyl methacrylate selectivity were about 100% and 71.4% respectively, after 30 min reaction.展开更多
The Pd-Pb catalyst supported on Al2O3 was prepared by the two-step impregnation method.The oxidative esterification of methacrolein （MAL） to methyl methacrylate （MMA） was carried out in a stainless bubble autoclav...The Pd-Pb catalyst supported on Al2O3 was prepared by the two-step impregnation method.The oxidative esterification of methacrolein （MAL） to methyl methacrylate （MMA） was carried out in a stainless bubble autoclave over the catalyst.The influences of the reaction conditions on catalytic activity were investigated in detail.The optimal reaction conditions were as follows: T=80℃, P=0.3 MPa, methanol∶MAL=8∶1 （ molar ratio ）, catalyst mass concentration in the reaction system 3.84%, pH of the reaction system 7—8, oxygen flux rate 30 ml·min -1 .Under the above conditions,MAL conversion and MMA selectivity reached 91% and 84%, respectively.The catalyst was recycled for seven times and still kept good selectivity.展开更多
RE elements La,Ce and Pr were added to catalysts for the oxidative esterification of methacrolein(MAL) to methyl methacrylate(MMA).Effects of RE elements proportion,pH,water content of material liquid and kinds of RE ...RE elements La,Ce and Pr were added to catalysts for the oxidative esterification of methacrolein(MAL) to methyl methacrylate(MMA).Effects of RE elements proportion,pH,water content of material liquid and kinds of RE elements on catalytic performance of catalysts were investigated.The results indicated that the addation of La,Ce and Pr in appropriate proportion could improve the catalyst’s activity.Addition of Pr was better than addition of La and Ce.Under the condition of reation temperature was 50℃,w%(catalyst)was 3.6%,proportion of Pr in the catalyst was 1%,pH of material liquid was 10.5,water conten of material liquid was 0% the yield of MMA reached up to 90.4%.展开更多
文摘以(NH_(4))_(6)Mo_(7)O_(24)·4H_(2)O、Bi(NO_(3))_(3)·5H_(2)O、Fe(NO_(3))_(3)·9H_(2)O、Co(NO_(3))_(2)·6H_(2)O和KNO_(3)为前驱体金属盐,通过共沉淀法制备了一系列MoBiFeCoK混合氧化物催化剂,考察了主金属Mo、Bi,助金属Fe、Co和掺杂金属K含量对催化剂催化异丁烯气相氧化反应的影响,通过SEM、EDX、XRD、NH_(3)-TPD对掺杂K前后的催化剂进行了表征,同时对催化异丁烯气相氧化反应条件进行了优化,并测试其100 h的催化稳定性。结果表明,Bi、Fe、Co和K的含量对MoBiFeCoK混合氧化物催化剂催化异丁烯气相氧化反应的性能有显著影响,其中,Mo_(12)Bi_(1.2)Fe_(3)Co_(8)K_(0.4)表现出最优催化性能;K的掺杂降低了催化剂酸量(从Mo12Bi1.2Fe3Co8的15.27μmol/g降至Mo_(12)Bi_(1.2)Fe_(3)Co_(8)K_(0.4)的5.91μmol/g),并明显提升主产物甲基丙烯醛(MAL)的选择性;异丁烯气相氧化反应的最佳条件为:以0.66 g Mo_(12)Bi_(1.2)Fe_(3)Co_(8)K_(0.4)为催化剂,反应温度320℃,n(O_(2))∶n(异丁烯)(氧烯比)=10∶1,体积空速(GHSV)=2000h^(-1)。在该条件下,Mo_(12)Bi_(1.2)Fe_(3)Co_(8)K_(0.4)在100h的催化异丁烯气相氧化反应中表现稳定,异丁烯转化率保持在98.6%,MAL选择性保持在86.4%。
文摘Ionic liquid（IL）,[bmim]PF6,was used in the reaction of one-step oxidative esterification from methacrolein to methyl methacrylate. It was found that ionic liquid not only increased the selectivity of methyl methacrylate but also inhibited its polymerization. The selectivity of methyl methacrylate was increased from 45% to 100% with ionic liquid. The experiment results showed that the content of ionic liquid had no effects on the selectivity of methyl methacrylate in a certain range of IL concentration,which indicated that ionic liquid could be used as a potential inhibitor of polymerization. [WT5HZ]
文摘Supported multi-metal catalyst was prepared by impregnation.A variety of factors such as reaction temperature, feedstock ratio, alkali concentration, catalyst concentration and antipolymerizer concentration were systematically investigated in terms of their effects on the oxidative esterification reaction for methyl methacrylate production from methacrolein.The experimental results showed that under the condition of temperature 333 K,methanol/methacrolein ratio 97∶1(molar ratio),NaOH concentration 0.001 g·ml^-1 and catalyst concentration 0.02 g·ml^-1, methacrolein conversion and methyl methacrylate selectivity were about 100% and 71.4% respectively, after 30 min reaction.
文摘The Pd-Pb catalyst supported on Al2O3 was prepared by the two-step impregnation method.The oxidative esterification of methacrolein （MAL） to methyl methacrylate （MMA） was carried out in a stainless bubble autoclave over the catalyst.The influences of the reaction conditions on catalytic activity were investigated in detail.The optimal reaction conditions were as follows: T=80℃, P=0.3 MPa, methanol∶MAL=8∶1 （ molar ratio ）, catalyst mass concentration in the reaction system 3.84%, pH of the reaction system 7—8, oxygen flux rate 30 ml·min -1 .Under the above conditions,MAL conversion and MMA selectivity reached 91% and 84%, respectively.The catalyst was recycled for seven times and still kept good selectivity.
文摘RE elements La,Ce and Pr were added to catalysts for the oxidative esterification of methacrolein(MAL) to methyl methacrylate(MMA).Effects of RE elements proportion,pH,water content of material liquid and kinds of RE elements on catalytic performance of catalysts were investigated.The results indicated that the addation of La,Ce and Pr in appropriate proportion could improve the catalyst’s activity.Addition of Pr was better than addition of La and Ce.Under the condition of reation temperature was 50℃,w%(catalyst)was 3.6%,proportion of Pr in the catalyst was 1%,pH of material liquid was 10.5,water conten of material liquid was 0% the yield of MMA reached up to 90.4%.
