Ethylene Oligomerization by (dppe)MCl_2 [M = Fe(II), Co(II),Ni(II)] Complexes/EAO

The catalytic properties of a series of (dppe) MCl2 [M = Fe(II), Co(II), Ni(II)] in combination with EAO (ethylaluminoxane) for ethylene oligomerization have been investigated. Treatment of the bidentate phosphine metal complexes with EAO in toluene generated in situ active catalysts which catalyze oligomerizaton of ethylene to low-carbon olefins. The effects of reaction temperature, ratios of n(Al) : n(M) and reaction periods on catalytic activity and product distribution have been studied. The activity of cobalt complex with EAO at 200C was 4021 g/g(Co)h, and the selectivity of C4-10 olefins is 95.5%.

A comparative techno-economic analysis for implementation of carbon dioxide to chemicals processes

CO_(2)-based carbon-neutral organics production processes could potentially reshape the chemical industry.However,their feasibility and net carbon footprint rely strongly on the sources of H_(2).Herein,we present a comprehensive comparative techno-economic analysis of CO_(2)-based methanol(CO_(2)TM)and aolefins(CO_(2)TO)manufacturing using various feedstock supply modes:(1)the standalone mode with external CO_(2)but H_(2)from on-site water electrolysis,(2)the integrated mode with both CO_(2)and H_(2)recovered from coal-chemical plants,and(3)the integrated mode with recycled CO_(2)but H_(2)from on-site water electrolysis.The integration of CO_(2)TM and CO_(2)TO into coal-to-olefins(CTO)and coal-to-methanol(CTM)facilities is currently cost-effective and can reduce net CO_(2)emissions by 65.7%and 68.5%,resulting in a three-fold and two-fold increase in carbon efficiency,respectively.As carbon tax policies and electrolysis technologies continue to evolve,standalone CO_(2)TM and CO_(2)TO are projected to become more economically competitive than CTO and CTM by 2035-2045.

Synergistic Effects of the ZnCl_2-SiCl_4 Modified TiCl_4/MgCl_2/THF Catalytic System on Ethylene/1-Hexene and Ethylene/1-Octene Copolymerizations

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.