A facile and user friendly technique to immobilize the late-transition metal complexes on spherical MgCl2/SiO2/THF support has been developed. The spherical MgCl2/SiO2/THF-supported late-transition metal catalysts 2,6...A facile and user friendly technique to immobilize the late-transition metal complexes on spherical MgCl2/SiO2/THF support has been developed. The spherical MgCl2/SiO2/THF-supported late-transition metal catalysts 2,6-bis-[1-(2,6-dimethylphenylimino)ethyl]pyridine iron(II) dichloride(SC-A) and 1,4-bis(2,6-dimethylphenyl)- acenaphthene diimine nickel(II) dibromide(SC-B) for ethylene polymerization has been prepared by spray-drying technique using tetrahydrofuran suspension containing MgCl2, SiO2 and late-transition metal complexes. The catalysts were characterized by BET, XRD, SEM and the polymers were analyzed using GPC, DSC and 13C-NMR. The test results show that spray-drying is a very effective method for immobilizing late-transition metal catalysts for ethylene polymerization. Among six kinds of cocatalysts for olefin polymerization, TMA and TEA were confirmed to be more effective than other compounds for the ethylene polymerization system using the catalyst SC-A. For the case of the catalyst SC-B, DEAC showed the best performance as cocatalysts in ethylene polymerization. The replication of the catalyst morphology was found in the resultant polyethylene.展开更多
The novel reactive transfer printing of silk was carried out through a hot-press adhesion and steaming. The special transfer paper was prepared by coating the paste mainly containing hot-melt adhesive hlgh-substituted...The novel reactive transfer printing of silk was carried out through a hot-press adhesion and steaming. The special transfer paper was prepared by coating the paste mainly containing hot-melt adhesive hlgh-substituted hydroxypropyl cellulose （H-HPC） and printing thickener earboxymethyl cellulose （CMC）. The effects of each ingredient in the paste on color yield of the prints and dye penetration were investigated. The major results indicate that, color yield is chiefly governed by the adhesion extent imparted by H-HPC, the type of fixing alkaline agent, and the content of urea. Trichloroacetic acid （TCAA） as the fixing alkaline agent and adding 5% urea can enhance the color depth obviously. Dye penetration depends on the coating quantity on the transfer paper, the contents of urea and dicyandiamide. The printed silk possesses a higher color yield, color fastness of grade 3 or above, clear sharpness, and good handle when the paste contains 3 % H-HPC, 0. 7 % CMC, 3 % TCAA, 5 % urea, 3 % dicyandiamide, and 0. 5 % physical sorbent nano-silica.展开更多
A series of carboxylated long chain polyethylene glycols(abbreviated as PEGCOOH) has been synthesized and used to support chloroplatinic acid.These supported catalysts were then tested for their efficiency in the hydr...A series of carboxylated long chain polyethylene glycols(abbreviated as PEGCOOH) has been synthesized and used to support chloroplatinic acid.These supported catalysts were then tested for their efficiency in the hydrosilylation of alkenes.The factors affecting their catalytic properties,e.g.relative molecular mass of polyethylene glycol,reaction temperature,platinum content,and type of alkenes,have been studied.It was found that the activity of the platinum catalyst decreased with increasing length of the polyethylene glycol chain,and increased with reaction temperature.Moreover,these catalysts could be reused several times without a noticeable decrease in activity or selectivity.The reaction pathway leading to excellent selectivity for the β-adduct of hydrosilylation of alkenes with triethoxysilane catalyzed by this catalysis system was discussed.展开更多
基金supported by the National Natural Science Foundation of China (Grant No.U1162114)the Science Foundation of Tianjin University of Science & Technology (20090420)
文摘A facile and user friendly technique to immobilize the late-transition metal complexes on spherical MgCl2/SiO2/THF support has been developed. The spherical MgCl2/SiO2/THF-supported late-transition metal catalysts 2,6-bis-[1-(2,6-dimethylphenylimino)ethyl]pyridine iron(II) dichloride(SC-A) and 1,4-bis(2,6-dimethylphenyl)- acenaphthene diimine nickel(II) dibromide(SC-B) for ethylene polymerization has been prepared by spray-drying technique using tetrahydrofuran suspension containing MgCl2, SiO2 and late-transition metal complexes. The catalysts were characterized by BET, XRD, SEM and the polymers were analyzed using GPC, DSC and 13C-NMR. The test results show that spray-drying is a very effective method for immobilizing late-transition metal catalysts for ethylene polymerization. Among six kinds of cocatalysts for olefin polymerization, TMA and TEA were confirmed to be more effective than other compounds for the ethylene polymerization system using the catalyst SC-A. For the case of the catalyst SC-B, DEAC showed the best performance as cocatalysts in ethylene polymerization. The replication of the catalyst morphology was found in the resultant polyethylene.
基金Jiangsu Province Project of Postgraduate Innovation Engineering,China(No.CXZZ12_0821)Industry-academic Joint Technological Innovations Fund Project of Jiangsu Province,China(No.BY2012120)Suzhou Project of Scientific and Technical Supporting,China(No.ZXS2012001)
文摘The novel reactive transfer printing of silk was carried out through a hot-press adhesion and steaming. The special transfer paper was prepared by coating the paste mainly containing hot-melt adhesive hlgh-substituted hydroxypropyl cellulose （H-HPC） and printing thickener earboxymethyl cellulose （CMC）. The effects of each ingredient in the paste on color yield of the prints and dye penetration were investigated. The major results indicate that, color yield is chiefly governed by the adhesion extent imparted by H-HPC, the type of fixing alkaline agent, and the content of urea. Trichloroacetic acid （TCAA） as the fixing alkaline agent and adding 5% urea can enhance the color depth obviously. Dye penetration depends on the coating quantity on the transfer paper, the contents of urea and dicyandiamide. The printed silk possesses a higher color yield, color fastness of grade 3 or above, clear sharpness, and good handle when the paste contains 3 % H-HPC, 0. 7 % CMC, 3 % TCAA, 5 % urea, 3 % dicyandiamide, and 0. 5 % physical sorbent nano-silica.
基金Supported by the Educational Commission of Zhejiang Province of China (Y201017419)Zhejiang Province Program(2008C14041)
文摘A series of carboxylated long chain polyethylene glycols(abbreviated as PEGCOOH) has been synthesized and used to support chloroplatinic acid.These supported catalysts were then tested for their efficiency in the hydrosilylation of alkenes.The factors affecting their catalytic properties,e.g.relative molecular mass of polyethylene glycol,reaction temperature,platinum content,and type of alkenes,have been studied.It was found that the activity of the platinum catalyst decreased with increasing length of the polyethylene glycol chain,and increased with reaction temperature.Moreover,these catalysts could be reused several times without a noticeable decrease in activity or selectivity.The reaction pathway leading to excellent selectivity for the β-adduct of hydrosilylation of alkenes with triethoxysilane catalyzed by this catalysis system was discussed.
