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In this work, the influences of the Ti oxidation state on the catalytic properties of MgCl_2-supported Ziegler–Natta catalysts in ethylene homo- and co-polymerization with 1-hexene. Three catalysts having different Ti oxidation states were synthesized by milling TiCl_4, TiCl_3, or TiCl_2 together with MgCl_2. With these catalysts having different Ti oxidation states, the polymerization conditions such as the Al concentration, temperature, and 1-hexene concentration were varied to figure out their catalytic abilities in ethylene homo- and co-polymerization. The Ti oxidation state affected the catalyst activity largely, having unique dependences on the polymerization conditions. A higher oxidation state led to a higher activity, slightly larger comonomer incorporation, and lower molecular weight as well as its narrower distribution. However, rough characteristics of copolymers were similar among the different Ti oxidation states., identifier:https://dspace.jaist.ac.jp/dspace/handle/10119/10718

In this work, the influences of the Ti oxidation state on the catalytic properties of MgCl_2-supported Ziegler–Natta catalysts in ethylene homo- and co-polymerization with 1-hexene. Three catalysts having different Ti oxidation states were synthesized by milling TiCl_4, TiCl_3, or TiCl_2 together with MgCl_2. With these catalysts having different Ti oxidation states, the polymerization conditions such as the Al concentration, temperature, and 1-hexene concentration were varied to figure out their catalytic abilities in ethylene homo- and co-polymerization. The Ti oxidation state affected the catalyst activity largely, having unique dependences on the polymerization conditions. A higher oxidation state led to a higher activity, slightly larger comonomer incorporation, and lower molecular weight as well as its narrower distribution. However, rough characteristics of copolymers were similar among the different Ti oxidation states.

A TiCl_4/ethylbenzoate/MgCl_2 Ziegler–Natta catalyst was pretreated with chemically different poisoning compounds to investigate their effects on the catalyst activity and stereospecificity for propylene polymerization. The poisoning power on the activity was in the order of methanol > acetone > ethyl acetate. A kinetic analysis using the stopped-flow method revealed that addition of the poisoning materials decreased the activity through the reduction of the number of active sites, whereas the catalyst isospecificity was hardly affected by these materials., identifier:https://dspace.jaist.ac.jp/dspace/handle/10119/8822

A TiCl_4/ethylbenzoate/MgCl_2 Ziegler–Natta catalyst was pretreated with chemically different poisoning compounds to investigate their effects on the catalyst activity and stereospecificity for propylene polymerization. The poisoning power on the activity was in the order of methanol > acetone > ethyl acetate. A kinetic analysis using the stopped-flow method revealed that addition of the poisoning materials decreased the activity through the reduction of the number of active sites, whereas the catalyst isospecificity was hardly affected by these materials.

Supported cobalt (Co) catalysts are the preferred catalysts for Fischer-Tropsch synthesis (FTS) based on natural gas. However, Co-support compound formation (Co-SCF) can result in lower activity. It has been found that water vapor present during standard reduction affects the degree of reducibility.The impact of water vapor on Co-SCF and the resulting characteristics of Co/g-Al2O3 and CoRu/ g-Al2O3 catalysts were investigated to develop a better understanding of Co-SCF and the effect of Ru promotion on this formation. The degree of reduction was lower when additional water vapor was introduced during reduction, but to a lesser degree when the Ru promoter was present. It is suggested that the Co "aluminate" formed is not identical to CoAl2O4 (spinel) but is probably a surface compound deficient in Co. This Co-SCF is a major cause for differences seen in the degree of reducibility, H2 chemisorption capacity, and Fischer-Tropsch synthesis (FTS) activity. To minimize Co-SCF, the effect of reduction gas containing carbon monoxide (CO) was investigated. A H2 flow containing CO (1-9 vol%) was used for standard reduction. After reduction, the pretreated catalyst samples were characterized and CO hydrogenation also performed. Both initial and steady-state rates went through a maximum for the addition of 3-5 vol% CO during standard reduction. It is concluded that the addition of CO during reduction has a significant effect on activity of the catalyst due to increases in both Co reducibility and dispersion. The effect of metal promoters, such as Cu and Zr on Co-SCF was also investigated. However, Cu addition was found to decrease FTS rate.The impact of Zr modification of alumina had a significant impact on the catalyst properties: FTS rate per gram catalyst increased by a factor of two and reducibility also increased. The impact of Zr modification is likely due to stabilization of the alumina support, prevention or blockage of Co surface "aluminate" formation, and an increase

Supported cobalt (Co) catalysts are the preferred catalysts for Fischer-Tropsch synthesis (FTS) based on natural gas. However, Co-support compound formation (Co-SCF) can result in lower activity. It has been found that water vapor present during standard reduction affects the degree of reducibility.The impact of water vapor on Co-SCF and the resulting characteristics of Co/g-Al2O3 and CoRu/ g-Al2O3 catalysts were investigated to develop a better understanding of Co-SCF and the effect of Ru promotion on this formation. The degree of reduction was lower when additional water vapor was introduced during reduction, but to a lesser degree when the Ru promoter was present. It is suggested that the Co "aluminate" formed is not identical to CoAl2O4 (spinel) but is probably a surface compound deficient in Co. This Co-SCF is a major cause for differences seen in the degree of reducibility, H2 chemisorption capacity, and Fischer-Tropsch synthesis (FTS) activity. To minimize Co-SCF, the effect of reduction gas containing carbon monoxide (CO) was investigated. A H2 flow containing CO (1-9 vol%) was used for standard reduction. After reduction, the pretreated catalyst samples were characterized and CO hydrogenation also performed. Both initial and steady-state rates went through a maximum for the addition of 3-5 vol% CO during standard reduction. It is concluded that the addition of CO during reduction has a significant effect on activity of the catalyst due to increases in both Co reducibility and dispersion. The effect of metal promoters, such as Cu and Zr on Co-SCF was also investigated. However, Cu addition was found to decrease FTS rate.The impact of Zr modification of alumina had a significant impact on the catalyst properties: FTS rate per gram catalyst increased by a factor of two and reducibility also increased. The impact of Zr modification is likely due to stabilization of the alumina support, prevention or blockage of Co surface "aluminate" formation, and an increase