The structure-performance relationship of Cu/Al_(2)O_(3) catalysts in the hydrogenation of diethyl oxalate(DEO)for the synthesis of alcohol ether esters has been investigated by various characterization techniques inc...The structure-performance relationship of Cu/Al_(2)O_(3) catalysts in the hydrogenation of diethyl oxalate(DEO)for the synthesis of alcohol ether esters has been investigated by various characterization techniques including XRD,XPS,N2O titration,and 27Al MAS-NMR.The results showed that when the crystal configurations of Al_(2)O_(3) were the same,increasing the specific surface area could effectively refine the size of copper nanoparticles(Cu NPs),and ultimately improve the conversion of DEO.Meanwhile,the smaller size ofγ-Al_(2)O_(3)(HSAl and SBAl)loaded Cu NPs promotes the reaction towards the deep hydrogenation to produce ethanol(EtOH)and ethylene glycol(EG).Besides,the larger size of Cu NPs on the surface of amorphous Al_(2)O_(3)(HTAl and SolAl)resulted in a lower conversion rate,where ethyl glycolate(Egly)is the main product.Despite there are differences in Al^(3+)ionic coordination in Al_(2)O_(3) with different crystal structures,the experimental data showed that the differences in Al^(3+)ionic coordination did not significantly affect the catalytic performance in the hydrogenation reaction.The formation of alcohol-ether ester chemicals is critically dependent on the interactions between Cu sites and acidic sites.Among them,EG and EtOH were dehydrated to form 2-ethoxyethanol via the SN2 mechanism,while Egly and EtOH were reacted to form ethyl ethoxyacetate(EEA)via the SN2 mechanism.This study provides a theoretical basis for the optimization of the coal-based glycol processes to achieve a diversified product portfolio.展开更多
A novel diether-ester conjugated electron donor model compound, 1,3-dimethoxypropan-2-yl benzoate, was synthesized via a reaction of 1,3-dimethoxypropan-2-ol and benzoyl chloride in the presence of triethyl amine and ...A novel diether-ester conjugated electron donor model compound, 1,3-dimethoxypropan-2-yl benzoate, was synthesized via a reaction of 1,3-dimethoxypropan-2-ol and benzoyl chloride in the presence of triethyl amine and 4-dimethylaminopryidine. Compared to the known routes of preparing diethers, which usually employ the reactions to O-alkylate the corresponding diols with O-alkylating reagents, the presented method here provides a new way to prepare the diether electron donor compounds. It avoids employing the traditional O-alkylation reactions, so that highly toxic O-alkylating chemicals, such as iodomethane, and very strong basic deprotonating reagents, such as alkoxides or metal hydrides, are not required. The product can be obtained in high yields without complicated purification processes. Catalyst component containing the electron donor compound was prepared and used to catalyze propylene polymerization.展开更多
A diamine containing ether and ester units, as basic monomer for the preparation of polyamides, was prepared via three consecutive reactions. Nucleophilic substitution reaction of 1,4-dihydroxy benzene with 4-nitroben...A diamine containing ether and ester units, as basic monomer for the preparation of polyamides, was prepared via three consecutive reactions. Nucleophilic substitution reaction of 1,4-dihydroxy benzene with 4-nitrobenzoyl chloride produced 4-hydroxyphenyl 4-nitrobenzoate （HPNB）. Reduction of nitro groups to amino groups using Fe and HC1 resulted in preparation of 4-hydroxyphenyl 4-aminobenzoate （HPAB）. The diamine was synthesized through nucleophilic substitution reaction of HPAB with 2,6-dichloropyridine. The precursors and diamine were fully characterized by common methods, and the diamine was polycondensed with different diacid chlorides in the presence of an acid scavenger to prepare new polyamides. The polyamides were characterized, and their physical properties including thermal stability and behavior, inherent viscosity and solubility were studied.展开更多
Two series of poly（imide-ester）s （PIEs） and poly（ether-imide-ester）s （PEIEs）, having benzoxazole or benzothiazole pendent groups, were conveniently prepared by the diphenylchlorophosphate-activated direct poly...Two series of poly（imide-ester）s （PIEs） and poly（ether-imide-ester）s （PEIEs）, having benzoxazole or benzothiazole pendent groups, were conveniently prepared by the diphenylchlorophosphate-activated direct polyesterification of two bis（imide-carboxylic acid）s （1）, such as 2-[3,5-bis（N-trimellitimidoyl）phenyl]benzoxazole （lo） and 2-[3,5-bis（N- trimellitimidoyl）phenyl]benzothiazole （Is） and two bis（imide-ether-carboxylic acid）s （2）, such as 2-[3,5-bis（4- trimellitimidophenoxy）-phenyl]benzoxazole （2o）, and 2-[3,5-bis（4-trimellitimidophenoxy）-phenyl]benzothiazole （2s） with various aromatic dihydroxy compounds in the presence of pyridine and lithium chloride. The structures, solubilities and thermal properties of obtained polymers were investigated in detail. All of the resulting polymers were characterized by FTIR and IH-NMR spectroscopy and elemental analysis. All of the resulting polymers exhibited excellent solubility in common organic solvents, such as pyridine, tetrahydrofuran and m-cresol, as well as in polar organic solvents, such as N-methyl-2- pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide and dimethyl sulfoxide. The modified polymers were obtained in quantitative yields with inherent viscosities between 0.47 and 0.67 dl·g^-1 Experimental results indicated that all the polymers had glass transition temperature between 198 ℃ and 262 ℃, the decomposition temperature at 10% weight loss between 398 ℃ and 531 ℃ under nitrogen.展开更多
A rosmarinic acid derivative, tetramethyl ether of rosmarinic acid benzyl ester, was synthesized. This is the first report of building this structural skeleton.
A salvianolic acid A derivative, hexamethyl ether of salvianolic acid A benzyl ester, was synthesized in fourteen steps. The overall yield was 3.4 parts per thousand. The compound was identified by (1)HNMR and MS. Thi...A salvianolic acid A derivative, hexamethyl ether of salvianolic acid A benzyl ester, was synthesized in fourteen steps. The overall yield was 3.4 parts per thousand. The compound was identified by (1)HNMR and MS. This is the first report of building this structural skeleton.展开更多
Reaction products of 2,4,6-tris(4-phenyl-phenoxy)-1,3,5-triazine derived from 4-phenylphenol cyanate ester and phenyl glycidyl ether were analyzed. In addition to an isocyanurate compound and an oxazolidone compound w...Reaction products of 2,4,6-tris(4-phenyl-phenoxy)-1,3,5-triazine derived from 4-phenylphenol cyanate ester and phenyl glycidyl ether were analyzed. In addition to an isocyanurate compound and an oxazolidone compound which were well known as reaction products of cyanate esters and epoxy resins, compounds with hybrid ring structure of cyanurate/isocyanurate were determined. Gibbs free energies of the compound having hybrid ring structure of cyanurate/isocyanurate with two isocyanurate moiety were found to be lower than that of the compound with cyanurate ring structure through calculations. Calculation data supported the existence of hybrid ring structure of cy-anurate/isocyanurate. It was revealed that isomerization from cyanurate to isocyanurate occurs via hybrid ring structure of cyanurate/isocyanurate in the reaction of aryl cyanurate and epoxy.展开更多
文摘The structure-performance relationship of Cu/Al_(2)O_(3) catalysts in the hydrogenation of diethyl oxalate(DEO)for the synthesis of alcohol ether esters has been investigated by various characterization techniques including XRD,XPS,N2O titration,and 27Al MAS-NMR.The results showed that when the crystal configurations of Al_(2)O_(3) were the same,increasing the specific surface area could effectively refine the size of copper nanoparticles(Cu NPs),and ultimately improve the conversion of DEO.Meanwhile,the smaller size ofγ-Al_(2)O_(3)(HSAl and SBAl)loaded Cu NPs promotes the reaction towards the deep hydrogenation to produce ethanol(EtOH)and ethylene glycol(EG).Besides,the larger size of Cu NPs on the surface of amorphous Al_(2)O_(3)(HTAl and SolAl)resulted in a lower conversion rate,where ethyl glycolate(Egly)is the main product.Despite there are differences in Al^(3+)ionic coordination in Al_(2)O_(3) with different crystal structures,the experimental data showed that the differences in Al^(3+)ionic coordination did not significantly affect the catalytic performance in the hydrogenation reaction.The formation of alcohol-ether ester chemicals is critically dependent on the interactions between Cu sites and acidic sites.Among them,EG and EtOH were dehydrated to form 2-ethoxyethanol via the SN2 mechanism,while Egly and EtOH were reacted to form ethyl ethoxyacetate(EEA)via the SN2 mechanism.This study provides a theoretical basis for the optimization of the coal-based glycol processes to achieve a diversified product portfolio.
基金Beijing Research Institute of Chemical Industry for fnancial support (No. G6001-11-ZS-0215 and No. G6001-12-ZS-0266)
文摘A novel diether-ester conjugated electron donor model compound, 1,3-dimethoxypropan-2-yl benzoate, was synthesized via a reaction of 1,3-dimethoxypropan-2-ol and benzoyl chloride in the presence of triethyl amine and 4-dimethylaminopryidine. Compared to the known routes of preparing diethers, which usually employ the reactions to O-alkylate the corresponding diols with O-alkylating reagents, the presented method here provides a new way to prepare the diether electron donor compounds. It avoids employing the traditional O-alkylation reactions, so that highly toxic O-alkylating chemicals, such as iodomethane, and very strong basic deprotonating reagents, such as alkoxides or metal hydrides, are not required. The product can be obtained in high yields without complicated purification processes. Catalyst component containing the electron donor compound was prepared and used to catalyze propylene polymerization.
文摘A diamine containing ether and ester units, as basic monomer for the preparation of polyamides, was prepared via three consecutive reactions. Nucleophilic substitution reaction of 1,4-dihydroxy benzene with 4-nitrobenzoyl chloride produced 4-hydroxyphenyl 4-nitrobenzoate （HPNB）. Reduction of nitro groups to amino groups using Fe and HC1 resulted in preparation of 4-hydroxyphenyl 4-aminobenzoate （HPAB）. The diamine was synthesized through nucleophilic substitution reaction of HPAB with 2,6-dichloropyridine. The precursors and diamine were fully characterized by common methods, and the diamine was polycondensed with different diacid chlorides in the presence of an acid scavenger to prepare new polyamides. The polyamides were characterized, and their physical properties including thermal stability and behavior, inherent viscosity and solubility were studied.
文摘Two series of poly（imide-ester）s （PIEs） and poly（ether-imide-ester）s （PEIEs）, having benzoxazole or benzothiazole pendent groups, were conveniently prepared by the diphenylchlorophosphate-activated direct polyesterification of two bis（imide-carboxylic acid）s （1）, such as 2-[3,5-bis（N-trimellitimidoyl）phenyl]benzoxazole （lo） and 2-[3,5-bis（N- trimellitimidoyl）phenyl]benzothiazole （Is） and two bis（imide-ether-carboxylic acid）s （2）, such as 2-[3,5-bis（4- trimellitimidophenoxy）-phenyl]benzoxazole （2o）, and 2-[3,5-bis（4-trimellitimidophenoxy）-phenyl]benzothiazole （2s） with various aromatic dihydroxy compounds in the presence of pyridine and lithium chloride. The structures, solubilities and thermal properties of obtained polymers were investigated in detail. All of the resulting polymers were characterized by FTIR and IH-NMR spectroscopy and elemental analysis. All of the resulting polymers exhibited excellent solubility in common organic solvents, such as pyridine, tetrahydrofuran and m-cresol, as well as in polar organic solvents, such as N-methyl-2- pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide and dimethyl sulfoxide. The modified polymers were obtained in quantitative yields with inherent viscosities between 0.47 and 0.67 dl·g^-1 Experimental results indicated that all the polymers had glass transition temperature between 198 ℃ and 262 ℃, the decomposition temperature at 10% weight loss between 398 ℃ and 531 ℃ under nitrogen.
文摘A rosmarinic acid derivative, tetramethyl ether of rosmarinic acid benzyl ester, was synthesized. This is the first report of building this structural skeleton.
文摘A salvianolic acid A derivative, hexamethyl ether of salvianolic acid A benzyl ester, was synthesized in fourteen steps. The overall yield was 3.4 parts per thousand. The compound was identified by (1)HNMR and MS. This is the first report of building this structural skeleton.
文摘Reaction products of 2,4,6-tris(4-phenyl-phenoxy)-1,3,5-triazine derived from 4-phenylphenol cyanate ester and phenyl glycidyl ether were analyzed. In addition to an isocyanurate compound and an oxazolidone compound which were well known as reaction products of cyanate esters and epoxy resins, compounds with hybrid ring structure of cyanurate/isocyanurate were determined. Gibbs free energies of the compound having hybrid ring structure of cyanurate/isocyanurate with two isocyanurate moiety were found to be lower than that of the compound with cyanurate ring structure through calculations. Calculation data supported the existence of hybrid ring structure of cy-anurate/isocyanurate. It was revealed that isomerization from cyanurate to isocyanurate occurs via hybrid ring structure of cyanurate/isocyanurate in the reaction of aryl cyanurate and epoxy.
