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
The catalysts used for manufacturing methyl methacrylate (MMA) by two-step conversion of isobutylene via methacrolein (MAL) were studied. The selective oxidation of isobutylene to MAL was carried out in a fixed-bed fl...The catalysts used for manufacturing methyl methacrylate (MMA) by two-step conversion of isobutylene via methacrolein (MAL) were studied. The selective oxidation of isobutylene to MAL was carried out in a fixed-bed flow microreactor using a series of Mo-Bi-containing catalysts and the oxidative esterification of MAL to MMA was carried out in a slurry-bed reactor using a series of palladium-containing catalysts.By means of BET and XPS, the properties of the catalysts were characterized.It was found that the performance of Mo-Bi-Co-Fe-Ce-O catalyst was improved distinctly when Cs was added for the selective oxidation of isobutylene to MAL, and the Pd 5Bi 2PbFe/CaCO 3 catalyst with the loading sequence of Pd, Pb and Bi, Fe showed the best performance for the oxidative esterification of MAL to MMA.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
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The catalysts used for manufacturing methyl methacrylate (MMA) by two-step conversion of isobutylene via methacrolein (MAL) were studied. The selective oxidation of isobutylene to MAL was carried out in a fixed-bed flow microreactor using a series of Mo-Bi-containing catalysts and the oxidative esterification of MAL to MMA was carried out in a slurry-bed reactor using a series of palladium-containing catalysts.By means of BET and XPS, the properties of the catalysts were characterized.It was found that the performance of Mo-Bi-Co-Fe-Ce-O catalyst was improved distinctly when Cs was added for the selective oxidation of isobutylene to MAL, and the Pd 5Bi 2PbFe/CaCO 3 catalyst with the loading sequence of Pd, Pb and Bi, Fe showed the best performance for the oxidative esterification of MAL to MMA.
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.
