Activated carbon was tested as metal-free catalyst for hydrochlorination of acetylene in order to circumvent the problem of environment pollution caused by mercury and high cost by noble metals. Oxygen-doped and nitro...Activated carbon was tested as metal-free catalyst for hydrochlorination of acetylene in order to circumvent the problem of environment pollution caused by mercury and high cost by noble metals. Oxygen-doped and nitrogen-doped activated carbons were prepared and characterized by XPS, TPD and N2 physisorption methods. The influences of the surface functional groups on the catalytic performance were discussed base on these results. Among all the samples tested, a nitrogen-doped sample, AC-n-US00, exhibited the best performance, the acety- lene conversion being 92% and vinyl chloride selectivity above 99% at 240 ~C and C2H2 hourly space velocity 30 h- 1. Moreover, the AC-n-US00 catalyst exhibited a stable performance during a 200 h test with a conversion of acetylene higher than 76% at 210 ~C at a C2H2 hourly space velocity 50 h 1. In contrary, oxygen-doped catalyst had lower catalytic activities. A linear relationship between the amount of pyrrolic-N and quaternary-N species and the catalytic activity was observed, indicating that these nitrogen-doped species might be the active sites and the key in tuning the catalytic performance. It is also found that the introduction of nitrogen species into the sample could significantly increase the adsorption amount of acetylene. The deactivation of nitrogen- doped activated carbon might be caused by the decrease of the accessibility to or the total amount of active sites.展开更多
In this paper iron complex with 5,10,15,20-tetraphenyl porphyrin inside NaX zeolite nanocages was capsuled. All synthesized homogeneous and heterogeneous catalysts were applied for epoxidation of α-pinene. It has bee...In this paper iron complex with 5,10,15,20-tetraphenyl porphyrin inside NaX zeolite nanocages was capsuled. All synthesized homogeneous and heterogeneous catalysts were applied for epoxidation of α-pinene. It has been shown that hydrophobic porphyrins are anchored inside the zeolite pores according to flexible ligand method. It also has been examined that capsulation of metalloporphyrins inside the pores of solid supports change catalytic activity and stability. All catalysts were characterized by Fourier transform infrared （FTIR）, UV/Vis diffuse reflectance spectroscopic （DRS）, scanning electron microscopy （SEM） analyses to confirm the complexes immobilization.展开更多
Co-or Mn-substituted LTL zeolites were hydrothermally synthesized by a novel organic-ligand-assisted method.XRD,UVVis DRS,XPS,and EPR techniques verified that the Co and Mn ions were incorporated into the zeolite fram...Co-or Mn-substituted LTL zeolites were hydrothermally synthesized by a novel organic-ligand-assisted method.XRD,UVVis DRS,XPS,and EPR techniques verified that the Co and Mn ions were incorporated into the zeolite framework.No organic species were retained in as-synthesized Co or Mn-LTL zeolites,which resulted in porous materials without calcination.In the oxidation of cyclohexane with tert-butyl hydroperoxide(TBHP),the Co-LTL and Mn-LTL gave a 40%–48%KA oil(cyclohexanone and cyclohexanol)yield as well as nearly 100%TBHP conversion under mild reaction conditions.The reactions were confirmed to be heterogeneous and to have proceeded catalytically.No loss of catalytic activity or leaching of metal active sites ions were observed during 4 reuses.展开更多
Three new homochiral bis-diamine-bridged bi-Mn（salen） complexes were synthesized. Their catalysis on asymmetric epoxidation of a-methylstyrene, styrene and indene was studied with NaC10 and m-CPBA as oxidants respec...Three new homochiral bis-diamine-bridged bi-Mn（salen） complexes were synthesized. Their catalysis on asymmetric epoxidation of a-methylstyrene, styrene and indene was studied with NaC10 and m-CPBA as oxidants respectively. This homogeneous catalyst exhibited comparable catalytic activity and enantioselectivity to the Jacobsen＇s catalyst in the asymmetric epoxidation of unfunctionalized olefins. Furthermore, the catalyst could be conveniently recovered and reused at least five times without significant losses of both activity and enantioselectivity. Specially, it also could be efficiently used in large-scale reactions with superior catalytic disposition being maintained at the same level, which provided the potential for the applications in industry. The effect of axial bases, temperature and solvent on activity and enantioselectivity of the catalytic system were also studied.展开更多
基金Supported by the National Natural Science Foundation of China(21476207)the National Basic Research Program of China(2011CB710800)
文摘Activated carbon was tested as metal-free catalyst for hydrochlorination of acetylene in order to circumvent the problem of environment pollution caused by mercury and high cost by noble metals. Oxygen-doped and nitrogen-doped activated carbons were prepared and characterized by XPS, TPD and N2 physisorption methods. The influences of the surface functional groups on the catalytic performance were discussed base on these results. Among all the samples tested, a nitrogen-doped sample, AC-n-US00, exhibited the best performance, the acety- lene conversion being 92% and vinyl chloride selectivity above 99% at 240 ~C and C2H2 hourly space velocity 30 h- 1. Moreover, the AC-n-US00 catalyst exhibited a stable performance during a 200 h test with a conversion of acetylene higher than 76% at 210 ~C at a C2H2 hourly space velocity 50 h 1. In contrary, oxygen-doped catalyst had lower catalytic activities. A linear relationship between the amount of pyrrolic-N and quaternary-N species and the catalytic activity was observed, indicating that these nitrogen-doped species might be the active sites and the key in tuning the catalytic performance. It is also found that the introduction of nitrogen species into the sample could significantly increase the adsorption amount of acetylene. The deactivation of nitrogen- doped activated carbon might be caused by the decrease of the accessibility to or the total amount of active sites.
文摘In this paper iron complex with 5,10,15,20-tetraphenyl porphyrin inside NaX zeolite nanocages was capsuled. All synthesized homogeneous and heterogeneous catalysts were applied for epoxidation of α-pinene. It has been shown that hydrophobic porphyrins are anchored inside the zeolite pores according to flexible ligand method. It also has been examined that capsulation of metalloporphyrins inside the pores of solid supports change catalytic activity and stability. All catalysts were characterized by Fourier transform infrared （FTIR）, UV/Vis diffuse reflectance spectroscopic （DRS）, scanning electron microscopy （SEM） analyses to confirm the complexes immobilization.
基金supported by the National Natural Science Foundation of China(21373089,U1162102)the PhD Programs Foundation of the Ministry of Education(2012007613000)+1 种基金the National Key Technology R&D Program(2012BAE05B02)the Shanghai Leading Academic Discipline Project(B409)
文摘Co-or Mn-substituted LTL zeolites were hydrothermally synthesized by a novel organic-ligand-assisted method.XRD,UVVis DRS,XPS,and EPR techniques verified that the Co and Mn ions were incorporated into the zeolite framework.No organic species were retained in as-synthesized Co or Mn-LTL zeolites,which resulted in porous materials without calcination.In the oxidation of cyclohexane with tert-butyl hydroperoxide(TBHP),the Co-LTL and Mn-LTL gave a 40%–48%KA oil(cyclohexanone and cyclohexanol)yield as well as nearly 100%TBHP conversion under mild reaction conditions.The reactions were confirmed to be heterogeneous and to have proceeded catalytically.No loss of catalytic activity or leaching of metal active sites ions were observed during 4 reuses.
基金financially supported by National Ministry of Science and Technology Innovation Fund for High-tech Small and Medium Enterprise Technology (09C26215112399)National Ministry of Human Resources and Social Security Start-up Support Projects for Students Returned to Business, Office of Human Resources and Social Security Issued 2009 (143)
文摘Three new homochiral bis-diamine-bridged bi-Mn（salen） complexes were synthesized. Their catalysis on asymmetric epoxidation of a-methylstyrene, styrene and indene was studied with NaC10 and m-CPBA as oxidants respectively. This homogeneous catalyst exhibited comparable catalytic activity and enantioselectivity to the Jacobsen＇s catalyst in the asymmetric epoxidation of unfunctionalized olefins. Furthermore, the catalyst could be conveniently recovered and reused at least five times without significant losses of both activity and enantioselectivity. Specially, it also could be efficiently used in large-scale reactions with superior catalytic disposition being maintained at the same level, which provided the potential for the applications in industry. The effect of axial bases, temperature and solvent on activity and enantioselectivity of the catalytic system were also studied.
