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이상량,정유성,신재순,김영철,박남국 한국공업화학회 2002 응용화학 Vol.6 No.2
Partial oxidation of ethylene to ethylene oxide was studied using silver caralystsiadeposited on a low surface area support, such as d-alum(< 1 m^2/g). Theselectivity to ethylene oxide has been reported to be related to the surface area ofactive silver species. Thus the activity of silver catalysts was studied in view of theparticle size of Ag.The catalyst prepared by water-alcihol method showed higheractivity. The addition of Cs as a promoter at higher temperature was observed toincrease catalytic activity of silver catalysts, presumably by increasing the surfaceares of active silver.
Lee, Sang Ryang,Lee, Yong Jun,Hong, Sung Gil,Kim, Young Chul,Park, Nam Cook,Moon, Dong-Ju 한국공업화학회 2003 응용화학 Vol.7 No.1
Partial oxidation of ethylene to ethylene oxide was studied over Ag/α-AI_2O_3 catalysts. To elucidate the effect of particle size on selectivity, the Ag/α-Al_2O_3 catalysts were prepared by water-alcohol methods and then calcined by changing calcination, time and atmospheric conditions. BET surface areas of catalysts before and after the reaction were characterized by N_2 physisorption and the particle size of Ag was measured by TEM and XRD analysis. It was found that the Ag/α-Al_2O_3catalyst calcined at 673 K for 2 h in air atmosphere showed higher activity than the other cataalysts. It was also found that the Ag/α-Al_2O_3 catalysts with Ag particle of about 30 nm were more stable and better active than the other catalysts.
정유성,이상량,신재순,김영철,박남국 한국공업화학회 2002 응용화학 Vol.6 No.2
Nano-sized silver catalysts have been prepared by alcohol and dioctyl esterof sodium sulphosuccinic acid, anionic surfactant, Aerosol OT(AOT). TOD/TPR andethylene oxide activity have been studied to investigate the characteristics of silvercatalysts. The sizes of Ag particles were estimated to be 10∼16 nm and the peak ofsilver oxide was not observed by XRD except for metallic silver. The desorptionpeak of molecular oxygen by TPD/TPR uniqely observed at about 400 ℃ in thecatalyst prepared by water-alcohol method. However, in the catalyst prepared bymicroemulsion method, the desorption peaks of molecular and atomic oxygens wereobserved at about 400 ℃ and 600 ℃, respectivly. The catalyst prepared by water-alcohol method showed higher activity ethylene oxide than the catalyst prepared by microemulsion method. It eems due to the larger silver particles and easier desorption of molecular oxygen from the catalyst prepared by water-alcohol method.
정정조,문동주,이용준,이상량,홍성길,안병성 한국공업화학회 2003 응용화학 Vol.7 No.1
The dimerization reaction of tetrafluoroethylene (CF_2=CF_2, TFE)was carried out to produce octafluorocyclobutane (C_4F_8 RC318). In order to control the reaction temperature for an exothermic dimerization of TFE, the fluidized bed reactor was employed with wteam. RC318 was produced with a little amount of by-products such as Hexafluoropropylene (CF_3CF=CF_2), Trifluoroethylene (CF_2=CHF_1TrFE), pentafluoroethylene (CHF_2CF_3, R125), Chlorotrlfluoropentane (CF_2=CFCL_!CTFE). The conversion of RC318 were greatly affected by the temperature and the contact time. The selectivity of HFP in the dimerization of TFE greaty increased by feeding steam in a fluidized bed reactor. It was found that the formation of solid polymer was minimized in a fluidized bed reactor system.