A novel room-temperature ionic liquid (RTIL),1-allyl,3-methylimidazolium chloride (［AMIM］Cl),was synthesized,ch aracterized and used for dissolving cellulose.The solubility of cellulose in ［ AMIM］Cl was better tha...A novel room-temperature ionic liquid (RTIL),1-allyl,3-methylimidazolium chloride (［AMIM］Cl),was synthesized,ch aracterized and used for dissolving cellulose.The solubility of cellulose in ［ AMIM］Cl was better than in 1-butyl,3-methylimidazolium (［BMIM］Cl).The pris tine cellulose and two cellulose samples regenerated from ［AMIM］Cl and ［BMIM ］Cl solutions were compared by FTIR,WAXD and TGA measurements.Results show t hat these two RTILs are non-derivatizing solvents for cellulose.After regenera tion from RTIL solutions,the crystalline form of cellulose films is completely transformed from cellulose Ⅰ to cellulose Ⅱ.Compared to pristine cellulose,t he regenerated cellulose exhibits a lower onset temperature of thermal decomposi tion,with a higher char yield.展开更多
The ethylene homopolymerization with new MgCl\-2\|supported bimetallic complex catalysts Ti(OBu)Cl\-3/Et(Ind)\-2ZrCl\-2 and Ti(OBu)Cl\-3/Cp\-2ZrCl\-2 was studied.The catalyst systems show high activity and the polyeth...The ethylene homopolymerization with new MgCl\-2\|supported bimetallic complex catalysts Ti(OBu)Cl\-3/Et(Ind)\-2ZrCl\-2 and Ti(OBu)Cl\-3/Cp\-2ZrCl\-2 was studied.The catalyst systems show high activity and the polyethylene with broad molecular weight distribution(MWD) was produced.The MgCl\-2\|supported bimetallic complex catalysts contain traditional Z\|N catalyst and movel metallocenes.Two active sites of Ti and Zr have different chain propagation,transfer,termination rate constant of olefin polymerization and bimodal and trimodal MWD polyethylene was produced.Molecular weiht distribution can be regulated easily by varying polymerzation conditions for improved processability and mechanical properties.Molecular weight,molecular weight distribution, T \-m and crystallinity were measured by GPC and DSC.展开更多
A new iron based catalyst 2,6\|bis[(1\|fluorenylimino)ethyl] pyridine iron dicloride (2) was synthesized via Shiff base condensation with 2,6\|diacetylpyridine and 9\|aminofluorene hydrochloride under formic acid as c...A new iron based catalyst 2,6\|bis[(1\|fluorenylimino)ethyl] pyridine iron dicloride (2) was synthesized via Shiff base condensation with 2,6\|diacetylpyridine and 9\|aminofluorene hydrochloride under formic acid as catalyst.Ethylene oligomerizations were carried out using this new catalyst and methylaluminoxane as cocatalyst under various conditions.The effects of Al/Fe molar ratio,reaction temperature and ethylene pressure on catalytic activity and product distribution were investigated.This novel catalyst had a good activity for ethylene oligomerization (e.g. 4 21×10 6g oligomers\5mol -1 Fe·h -1 ,Al/Fe molar ratio=2000,reaction temperature=40℃,ethylene pressure=1 5?MPa).The catalytic activity increased with the increasing concentration of MAO.The tendency to produce more C 4～C 10 olefins was attributed to the more chain transfer reactions to MAO.The higher the reaction temperature,the lower catalytic activity was present.The reasonable explanation was the combination of the accelerated catalyst’s deactivation and the decrease in ethylene concentration in solvent due to the elevated temperature.Under such condition,however,the oligomerization of ethylene produced more short chain olefins which are adapted to act as comonomers for preparation of linear low density polyethylene materials.Ethylene pressure in autoclave also had an important influence on catalytic activity and carbon\|number distribution of product.The catalytic activity increased sharply with the elevated ethylene pressure.However,the proportion of C 4～C 10 olefins in product decreased in higher pressure due to the enhanced chain propagation reaction.The research work indicated that the control of catalytic activity and product distribution can be realized by the variation of oligomerization conditions such as Al/Fe molar ratio,reaction temperature and ethylene pressure.The results also showed that the ethylene oligomerization employing this novel iron\|based catalyst mainly produces the C 4～C 10 olefins with high selectivity for linear C 4～C 10 α \|olefin (>98%).展开更多
文摘A novel room-temperature ionic liquid (RTIL),1-allyl,3-methylimidazolium chloride (［AMIM］Cl),was synthesized,ch aracterized and used for dissolving cellulose.The solubility of cellulose in ［ AMIM］Cl was better than in 1-butyl,3-methylimidazolium (［BMIM］Cl).The pris tine cellulose and two cellulose samples regenerated from ［AMIM］Cl and ［BMIM ］Cl solutions were compared by FTIR,WAXD and TGA measurements.Results show t hat these two RTILs are non-derivatizing solvents for cellulose.After regenera tion from RTIL solutions,the crystalline form of cellulose films is completely transformed from cellulose Ⅰ to cellulose Ⅱ.Compared to pristine cellulose,t he regenerated cellulose exhibits a lower onset temperature of thermal decomposi tion,with a higher char yield.
文摘The ethylene homopolymerization with new MgCl\-2\|supported bimetallic complex catalysts Ti(OBu)Cl\-3/Et(Ind)\-2ZrCl\-2 and Ti(OBu)Cl\-3/Cp\-2ZrCl\-2 was studied.The catalyst systems show high activity and the polyethylene with broad molecular weight distribution(MWD) was produced.The MgCl\-2\|supported bimetallic complex catalysts contain traditional Z\|N catalyst and movel metallocenes.Two active sites of Ti and Zr have different chain propagation,transfer,termination rate constant of olefin polymerization and bimodal and trimodal MWD polyethylene was produced.Molecular weiht distribution can be regulated easily by varying polymerzation conditions for improved processability and mechanical properties.Molecular weight,molecular weight distribution, T \-m and crystallinity were measured by GPC and DSC.
文摘A new iron based catalyst 2,6\|bis[(1\|fluorenylimino)ethyl] pyridine iron dicloride (2) was synthesized via Shiff base condensation with 2,6\|diacetylpyridine and 9\|aminofluorene hydrochloride under formic acid as catalyst.Ethylene oligomerizations were carried out using this new catalyst and methylaluminoxane as cocatalyst under various conditions.The effects of Al/Fe molar ratio,reaction temperature and ethylene pressure on catalytic activity and product distribution were investigated.This novel catalyst had a good activity for ethylene oligomerization (e.g. 4 21×10 6g oligomers\5mol -1 Fe·h -1 ,Al/Fe molar ratio=2000,reaction temperature=40℃,ethylene pressure=1 5?MPa).The catalytic activity increased with the increasing concentration of MAO.The tendency to produce more C 4～C 10 olefins was attributed to the more chain transfer reactions to MAO.The higher the reaction temperature,the lower catalytic activity was present.The reasonable explanation was the combination of the accelerated catalyst’s deactivation and the decrease in ethylene concentration in solvent due to the elevated temperature.Under such condition,however,the oligomerization of ethylene produced more short chain olefins which are adapted to act as comonomers for preparation of linear low density polyethylene materials.Ethylene pressure in autoclave also had an important influence on catalytic activity and carbon\|number distribution of product.The catalytic activity increased sharply with the elevated ethylene pressure.However,the proportion of C 4～C 10 olefins in product decreased in higher pressure due to the enhanced chain propagation reaction.The research work indicated that the control of catalytic activity and product distribution can be realized by the variation of oligomerization conditions such as Al/Fe molar ratio,reaction temperature and ethylene pressure.The results also showed that the ethylene oligomerization employing this novel iron\|based catalyst mainly produces the C 4～C 10 olefins with high selectivity for linear C 4～C 10 α \|olefin (>98%).
