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Chinese Journal of Polymer Science 2014年第1期32卷 84-91页

作者： Wanna Phiwkliang bunjerd jongsomjit Piyasan Praserthdam Center of Excellence on Catalysis and Catalytic Reaction Engineering Department of Chemical Engineering Faculty of Engineering Chulalongkorn University

The copolymerizations of ethylene with 1-hexene or 1-0ctene by using TiC14/MgCI2/THF catalysts modified with different metal halide additives （ZnCI2, SIC14, and the combined ZnC12-SiCl4） were investigated based on catalytic activity and copolymer properties. It was found that the catalyst modified with mixed ZnC12-SiC14 revealed the highest activities for both ethylene/1-hexene and ethylene/1-0ctene copolymerization. The increase in activities was due to the formation of acidic sites by modifying the catalysts with Lewis acids. Based on the FTIR measurements, the characteristic C--O--C peaks of the catalysts modified with metal halide additives were slightly shifted to lower wavenumber when compared to the unmodified catalyst. This showed that the modified catalysts could generate more acid sites in the TiC14/MgC12/THF catalytic system leading to an increase in activities as well as comonomer insertion （as proven by IaC-NMR）. However, Lewis acid- modifications did not affect the microstructure of the copolymers obtained. By comparison on the properties of copolymers prepared with the unmodified catalyst, it was found that polymers with ZnC12 and/or SIC14 modification exhibited a slight decrease in melting temperature, crystallinity and density. It is suggested that these results were obtained based on the different amount of ct-olefins insertion, regardless of the types of Lewis acids and comonomer.

关键词： Ziegler-Natta catalyst Lewis acid Copolymerization of ethylene with a-olefin SIC14 ZnC12.

Ti-Si composite oxide-supported cobalt catalysts for CO_2 hydrogenation

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Journal of Natural Gas Chemistry 2011年第5期20卷 558-564页

作者： Jakrapan Janlamool Piyasan Praserthdam bunjerd jongsomjit Center of Excellence on Catalysis and Catalytic Reaction Engineering Department of Chemical Engineering Faculty of Engineering Chulalongkorn University

In the present work, different silica-based supported cobalt （Co） catalysts were synthesized and used for CO2 hydrogenation for methanation. Different supports, such as SSP, MCM-41, TiSSP and TiMCM were used to prepare Co catalysts with 20 wt% Co loading. The supports and catalysts were characterized by means of N2 physisorption, XRD, SEM/EDX, XPS, TPR and CO chemisorption. It is found that after calcination of catalysts, Ti is present in the form of anatase. The introduction of Ti plays important roles in the properties of Co catalysts by：（i） facilitating the reduction of Co oxides species which are strongly interacted with support, （ii） preventing the formation of silicate compounds, and （iii） inhibiting the RWGS reaction. Based on CO2 hydrogenation, the CoTiMCM catalyst exhibites the highest activity and stability.

关键词： CO2 hydrogenation titania-silica cobalt catalysts methanation

LLDPE/TiO_2 nanocomposites produced from different crystallite sizes of TiO_2 via in situ polymerization

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Chinese Science Bulletin 2012年第17期57卷 2177-2184页

作者： CHAICHANA Ekrachan PATHOMSAP Somsakun MEKASUWANDUMRONG Okorn PANPRANOT Joongjai SHOTIPRUK Artiwan jongsomjit bunjerd Chemistry Program Faculty of Science and TechnologyNakhon Pathom Rajabhat UniversityNakhon Pathom 73000Thailand Faculty of Engineering Department of Chemical EngineeringCenter of Excellence on Catalysis and Catalytic Reaction EngineeringChulalongkorn UniversityBangkok 10330Thailand Faculty of Engineering and Industrial Technology Silapakorn UniversityNakhon Prathom 26000Thailand

Nano-TiO2 particles with a range of crystallite sizes were synthesized by a conventional sol-gel method,and then used as nanoparticle substrates in the synthesis of LLDPE/TiO2 nanocomposites via in situ polymerization of ethylene/1-hexene with zirconocene/MMAO *** was found that the size of the nano-TiO2 crystallite nanoparticles can influence the catalytic activity in the polymerization *** larger nano-TiO2 crystallites provided better catalytic activity in the polymerization system due to more space for monomer *** addition,by thermo-gravimetric analysis,it can be seen that the larger nano-TiO2 crystallites also exhibited lower interaction with available ***,the MMAO reacted more efficiently with the zirconocene catalyst during the activation process,and enhanced polymerization *** the polymer nanocomposites products did not have well defined melting temperature indicating non-crystalline *** is due to the high amount of hexene incorporation(based on 13C NMR).The difference in crystallite sizes of the nano-TiO2 also affected how 1-hexene became incorporated into the polymer *** smaller crystallite size of nano-TiO2 allowed greater 1-hexene incorporation due to depression of the reactivity of the *** contribution of this work helps develop a better understanding of the role of nano-TiO2 in the catalytic activity of the polymerization system and in the microstructure of the polymer composite ***,this study only considers work on the laboratory scale,so for commercial application of these results,it is necessary to scale up the polymerization *** is only at this stage,that other physical properties,such as the mechanical properties of these materials can be sensibly determined.

关键词：聚合物纳米复合材料纳米二氧化钛颗粒晶粒尺寸原位聚合高分子复合材料锆催化剂聚合体系 TiO2微晶

Oxidative dehydrogenation of ethanol over Cu/Mg-Al catalyst derived from hydrotalcite:effect of ethanol concentration and reduction conditions

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2020年第3期21卷 218-228页

作者： Piriya PINTHONG Piyasan PRASERTHDAM bunjerd jongsomjit Center of Excellence on Catalysis and Catalytic Reaction Engineering Department of Chemical EngineeringFaculty of EngineeringChulalongkorn UniversityBangkok 10330Thailand

The copper-modified Mg-Al catalyst(Cu/Mg-Al)was synthesized using the incipient wetness impregnation of copper onto the Mg-Al hydrotalcite derived from co-precipitation *** effects of copper on the characteristics of catalyst were obtained using several characterization *** found that only copper(I)oxide(Cu O)species were obtained on the surface after calcination in air by X-ray Diffraction(XRD).However,the basicity of the base decreases slightly,while the density of the base increases due to the decrease in Brunauer-Emmett-Teller(BET)surface *** carried out the catalytic activity of the Cu/Mg-Al catalyst in the continuous flow reactor through oxidative dehydrogenation of *** obtained that the copper enhances the catalytic activity in this reaction,and the ethanol conversion increases with increase in temperature,while the acetaldehyde selectivity decreases because of the decomposition of acetaldehyde to carbon *** highest acetaldehyde yield of 41.8%was at 350℃.Moreover,we studied the effects of the ethanol concentration by varying the ethanol feed concentrations(99.9%,75%,and 50%).The ethanol conversion decreases with a decrease in the ethanol concentration due to the high adsorption of water molecules on the catalyst ***,the negative effect decreases at higher reaction temperature(350–400℃).Furthermore,we investigated the effect of the reduction condition of catalyst by varying the reduction temperature(300 and 400℃).The reduction process affects the catalytic *** Cu/Mg-Al was comparatively stable for 10 h upon time-on-stream *** is used as a promising catalyst in oxidative dehydrogenation of ethanol without any reduction step.

关键词： Oxidative dehydrogenation Ethanol Copper Mg-Al hydrotalcite Acetaldehyde Catalyst

POISONING OF ACTIVE SITES ON ZIEGLER-NATTA CATALYST FOR PROPYLENE POLYMERIZATION

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Chinese Journal of Polymer Science 2008年第5期26卷 547-552页

作者： Kitti Tangjituabun Sang Yull Kim Yuichi Hiraoka Toshiaki Taniike Minoru Terano bunjerd jongsomjit Piyasan Praserthdam School of Materials Science Japan Advanced Institute of Science and TechnologyIshikawa 923-1292Japan Department of Chemical Engineering Chulalongkorn UniversityBangkok 10330Thailand

The effects of poisoning materials on catalytic activity and isospecificity of the supported Ziegler-Natta catalyst were investigated.A minor amount of simple structure of Lewis base,i.e.,methanol,acetone,ethyl acetate,was introduced into the catalyst slurry for partial poisoning catalytic active *** was found that the variations in deactivation power were in the order of methanol>acetone>ethyl *** kinetic investigation via stopped-flow polymerization showed that poisoning compounds cau...

关键词： Poisoning material Ziegler-Natta catalyst Stopped-flow propylene polymerization