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Formation of ethylene oxide (EO) on silver catalysts
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ing is planned for the 1998 Miami meeting. To find out more detail about the AIChE program, please check the latest updates on the WVWV: http://www/aiche.org. For information regarding membership contact Ms. T. Stevenson at [email protected], fax 212-752-3294. One-step Oxidization of Benzene to Phenol with Water as Oxidant The title reaction has been studied by Shengchun Cao et al. [Chin. J. Petrochem. Tech., 10 (1995) 708], using Fe-Cu-Mn oxides supported on sepiolite as catalysts. The catalysts were prepared by impregnating 35 g of a HNO3-treated commercial sepiolite powder (S=70.5 m 2 g-l) with an aqueous solution containing a suitable amount of Fe(NO3)3.9H20, 3.5 g Cu(NO3)3.3H20 and 1 g Mn(Ac)2.4H20, and this was followed by precipitation with 55 ml aqueous ammonia. The precipitate was washed with deionized water up to a pH of 11-11.5, then dried, and calcined at 600-650°C. The influence of the Fe3+ content of the catalyst, the pH value of the precipitate and the reaction temperature on catalytic activity has been investigated. It is claimed that a catalyst with 10% Fe3+ has the best performance, giving a conversion of benzene of over 14.8% and a selectivity of phenol over 96.9% at 200-~300°C and normal pressure with H20 as oxidant. Oxydehydrogenation of Ethylene (EB) to Styrene catalyzed by K-FeZSM-5 This paper concerns studies on the influence of the hydrothermal treatment and a dispersion of Fe203 on the oxydehydrogenation activity of EB over K-FeZSM-5 using catalytic tests as well as ESR and applied catalysis A: General
TPR techniques [Chunlei Zhang et al., Chin. J. Speciality Petrochem., 4 (1995) 60]. The K-Fe-ZSM-5 catalyst was prepared by ion exchange of a FeZSM-5 zeolite (synthesized by Inui's rapid synthesis method, Si/Fe=31.55) with KCI solution. The reaction was performed at 823 K with a feed ratio of EB:O2:N2=1:1:20. It was found that skeletal iron(Ill) in the FeZSM-5 was gradually changed to non-skeletal iron(Ill) and that this was accompanied by an increase of the acidity of the catalyst with increasing time of hydrothermal treatment. These effects were ascribed to the agglomeration of Fe203 and to the surface OH groups attached, as well as to a loss of K. A catalyst after hydrothermal treatment for 1 h, which had highly dispersed nonskeletal iron(Ill) and suitable acid-base properties, showed the highest activity for EB oxydehydrogenation compared with those treated for 4 h and 8 h, respectively. The authors believe that skeletal iron(Ill) and highly dispersed non-skeletal iron(Ill) are the active centres for ethylbenzene oxydehydrogenation.
Formation of Ethylene Oxide (EO) on Silver Catalysts
The Research Institute of Yanshan Petrochemical Company (YSRI), China, started to research and develop silver catalysts for the production of EO by vaporphase oxidation of ethylene since 1974. Up to now, a series of silver catalysts from type YS-1 to YS-6 have been developed. A catalyst called YS-4 was put into commercial application at YSPC in 1989. It gave a space time yield (STY) of 197 kg EO/h m 2 cat with an initial selectivity of 81 o'~ under the following conditions: T=238°C, Volume 138 No. 1 - - 25 April 1996
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SV=7301 h-1, feed gas composition (vol.%): C4H, 29.54, 02 5.81, C02 5.13. Since 1991, the YSRI has worked to develop new types of EO silver catalysts with high efficiency jointly with Tianjin Research Institute of Chemical Technology. By the end of 1993, a new catalyst, termed YS-6, had been successfully developed. In a single-tube test unit, the YS-6 catalyst gave a selectivity of 85-86% for EO, higher than that for YS-5 by 2%, with an improved stability and longer life time. The YS-6 catalyst was put into commercial application at YSPC in September 1994. [Source: Chin. J. Speciality Petrochemicals, 3 (1995) 1] Behaviour of Nickel Catalysts Prepared in a Magnetic Field This work has been reported by Qiao-li Liao, et al. [Chin. J. Catal., 16 (6) (1991) 437]. The nickel catalysts, 10% NiO on 7-AI203 and 10 NiO on 6% La203-7-AI203, were prepared by impregnation in a stable magnetic field of 30 T. The influence of the magnetic field on the physicochemical properties and catalytic properties of the catalysts were examined. The study shows that a magnetic field has no significant effect on the average particle size and lattice distortion of NiO. However, the magnetic field enhances the interaction between metal and support, resulting in the formation of NiAI204 and LaNi03 at lower temperatures and showing a retardative reduction of Ni. It is claimed that catalysts prepared in a magnetic field show lower activity and less carbon deposit in CO disproportionation than those prepared without a magnetic field.
applied catalysis A: General
Oxidation of Methane to Methanol In a Reactant-Swept Catalytic Membrane Reactor (RSCMR) The RSCMR was composed of a 12 mm diameter inner-tube comprising of a Si02 micropore membrane supported on a porous ceramic substrate prepared by the sol-gel method, and a 16 mm diameter stainless steel outer-tube to catalyze the oxidation of methane to methanol at atmospheric pressure. A reactant feed of methane and the oxidant mixture was first allowed to flow through the space between the inner and outer tubes of the reactor. Product methanol which had permeated through the membrane was removed by the high-flow sweep gas. The reactant mixture was then recycled into the catalyst bed in the inner tube of the reactor after the methanol had been absorbed in an icewater bath. The product methanol which had not permeated through the membrane was also absorbed in an ice-water bath. The study shows that an increase of concentration of oxygen or methane in the reactant feed and of the flow rate favour an increase in the yield of methanol under the experimental conditions used. The yield of methanol in the RSCMR is higher than in a CMR; e.g., at 700°C, the yield of methanol in a CMR is 0.5 g/m 2 h and in a RSCMR it is 0.9 g/m 2 h. It was also shown that the decomposition of methanol in the RSCMR was slower than that in the CMR. The temperatures at which 50% of the methanol decomposed in the CMNR and RSCMR were about 340 and 430°C, respectively. A high flow of the sweep gas in the RSCMR inhibits the decomposition of the product methanol. [Source: Chin. J. Fuel Chem. and Techn., 23 (3) (1995) 312]
Volume 138 No. 1 - - 25 April 1996
ing is planned for the 1998 Miami meeting. To find out more detail about the AIChE program, please check the latest updates on the WVWV: http://www/aiche.org. For information regarding membership contact Ms. T. Stevenson at [email protected], fax 212-752-3294. One-step Oxidization of Benzene to Phenol with Water as Oxidant The title reaction has been studied by Shengchun Cao et al. [Chin. J. Petrochem. Tech., 10 (1995) 708], using Fe-Cu-Mn oxides supported on sepiolite as catalysts. The catalysts were prepared by impregnating 35 g of a HNO3-treated commercial sepiolite powder (S=70.5 m 2 g-l) with an aqueous solution containing a suitable amount of Fe(NO3)3.9H20, 3.5 g Cu(NO3)3.3H20 and 1 g Mn(Ac)2.4H20, and this was followed by precipitation with 55 ml aqueous ammonia. The precipitate was washed with deionized water up to a pH of 11-11.5, then dried, and calcined at 600-650°C. The influence of the Fe3+ content of the catalyst, the pH value of the precipitate and the reaction temperature on catalytic activity has been investigated. It is claimed that a catalyst with 10% Fe3+ has the best performance, giving a conversion of benzene of over 14.8% and a selectivity of phenol over 96.9% at 200-~300°C and normal pressure with H20 as oxidant. Oxydehydrogenation of Ethylene (EB) to Styrene catalyzed by K-FeZSM-5 This paper concerns studies on the influence of the hydrothermal treatment and a dispersion of Fe203 on the oxydehydrogenation activity of EB over K-FeZSM-5 using catalytic tests as well as ESR and applied catalysis A: General
TPR techniques [Chunlei Zhang et al., Chin. J. Speciality Petrochem., 4 (1995) 60]. The K-Fe-ZSM-5 catalyst was prepared by ion exchange of a FeZSM-5 zeolite (synthesized by Inui's rapid synthesis method, Si/Fe=31.55) with KCI solution. The reaction was performed at 823 K with a feed ratio of EB:O2:N2=1:1:20. It was found that skeletal iron(Ill) in the FeZSM-5 was gradually changed to non-skeletal iron(Ill) and that this was accompanied by an increase of the acidity of the catalyst with increasing time of hydrothermal treatment. These effects were ascribed to the agglomeration of Fe203 and to the surface OH groups attached, as well as to a loss of K. A catalyst after hydrothermal treatment for 1 h, which had highly dispersed nonskeletal iron(Ill) and suitable acid-base properties, showed the highest activity for EB oxydehydrogenation compared with those treated for 4 h and 8 h, respectively. The authors believe that skeletal iron(Ill) and highly dispersed non-skeletal iron(Ill) are the active centres for ethylbenzene oxydehydrogenation.
Formation of Ethylene Oxide (EO) on Silver Catalysts
The Research Institute of Yanshan Petrochemical Company (YSRI), China, started to research and develop silver catalysts for the production of EO by vaporphase oxidation of ethylene since 1974. Up to now, a series of silver catalysts from type YS-1 to YS-6 have been developed. A catalyst called YS-4 was put into commercial application at YSPC in 1989. It gave a space time yield (STY) of 197 kg EO/h m 2 cat with an initial selectivity of 81 o'~ under the following conditions: T=238°C, Volume 138 No. 1 - - 25 April 1996
N9
SV=7301 h-1, feed gas composition (vol.%): C4H, 29.54, 02 5.81, C02 5.13. Since 1991, the YSRI has worked to develop new types of EO silver catalysts with high efficiency jointly with Tianjin Research Institute of Chemical Technology. By the end of 1993, a new catalyst, termed YS-6, had been successfully developed. In a single-tube test unit, the YS-6 catalyst gave a selectivity of 85-86% for EO, higher than that for YS-5 by 2%, with an improved stability and longer life time. The YS-6 catalyst was put into commercial application at YSPC in September 1994. [Source: Chin. J. Speciality Petrochemicals, 3 (1995) 1] Behaviour of Nickel Catalysts Prepared in a Magnetic Field This work has been reported by Qiao-li Liao, et al. [Chin. J. Catal., 16 (6) (1991) 437]. The nickel catalysts, 10% NiO on 7-AI203 and 10 NiO on 6% La203-7-AI203, were prepared by impregnation in a stable magnetic field of 30 T. The influence of the magnetic field on the physicochemical properties and catalytic properties of the catalysts were examined. The study shows that a magnetic field has no significant effect on the average particle size and lattice distortion of NiO. However, the magnetic field enhances the interaction between metal and support, resulting in the formation of NiAI204 and LaNi03 at lower temperatures and showing a retardative reduction of Ni. It is claimed that catalysts prepared in a magnetic field show lower activity and less carbon deposit in CO disproportionation than those prepared without a magnetic field.
applied catalysis A: General
Oxidation of Methane to Methanol In a Reactant-Swept Catalytic Membrane Reactor (RSCMR) The RSCMR was composed of a 12 mm diameter inner-tube comprising of a Si02 micropore membrane supported on a porous ceramic substrate prepared by the sol-gel method, and a 16 mm diameter stainless steel outer-tube to catalyze the oxidation of methane to methanol at atmospheric pressure. A reactant feed of methane and the oxidant mixture was first allowed to flow through the space between the inner and outer tubes of the reactor. Product methanol which had permeated through the membrane was removed by the high-flow sweep gas. The reactant mixture was then recycled into the catalyst bed in the inner tube of the reactor after the methanol had been absorbed in an icewater bath. The product methanol which had not permeated through the membrane was also absorbed in an ice-water bath. The study shows that an increase of concentration of oxygen or methane in the reactant feed and of the flow rate favour an increase in the yield of methanol under the experimental conditions used. The yield of methanol in the RSCMR is higher than in a CMR; e.g., at 700°C, the yield of methanol in a CMR is 0.5 g/m 2 h and in a RSCMR it is 0.9 g/m 2 h. It was also shown that the decomposition of methanol in the RSCMR was slower than that in the CMR. The temperatures at which 50% of the methanol decomposed in the CMNR and RSCMR were about 340 and 430°C, respectively. A high flow of the sweep gas in the RSCMR inhibits the decomposition of the product methanol. [Source: Chin. J. Fuel Chem. and Techn., 23 (3) (1995) 312]
Volume 138 No. 1 - - 25 April 1996