This report describes a new three‐component strategy for the regioselective synthesis of a series of tri‐substituted pyridazines via a 1,4‐diazabicyclo[2.2.2]octane （DABCO）‐catalyzed condensation of propiophenon...This report describes a new three‐component strategy for the regioselective synthesis of a series of tri‐substituted pyridazines via a 1,4‐diazabicyclo[2.2.2]octane （DABCO）‐catalyzed condensation of propiophenones, arylglyoxalmonohydrates and hydrazine hydrate in water. This method provides a green and convenient one‐pot route toward a diverse set of 3,6‐diaryl‐4‐methylpyridazines bearing various aryl substituents. This procedure is highly regioselective, operationally simple, uses water as a safe, environmentally friendly solvent, and DABCO as a green base‐organocatalyst, and affords good to excellent yields of products.展开更多
Pyrolysis of polytrimethylene terephthalate(PTT) fiber has been investigated by pyrolysis gas chromatography-mass spectroscopy in the temperature range from 400℃ to 750℃ in order to observe the possible effect of th...Pyrolysis of polytrimethylene terephthalate(PTT) fiber has been investigated by pyrolysis gas chromatography-mass spectroscopy in the temperature range from 400℃ to 750℃ in order to observe the possible effect of the temperature on its composition of pyrolysates.At 400℃,pyrolysis of molecular chain could occur,only 13 pyrolysates could be identified.The trimethylene moieties bound to the macromolecular core by ester bonds are cleaved at around 400℃.At 550℃-750℃,pyrolysis of molecular chain could completely take place,46 pyrolysates could be found.As the temperature increases,the compositions of pyrolysate are distinctly increased.Several compounds,especially benzoic acid,monopropenyl-p-phthalate,2-propenyl benzoate,di-2-propenyl ester,1,4-benzenedicarboxylic acid,benzene,1,5-hexadiene,biphenyl and 1,3-propanediol dibenzoate could be formed.The thermal degradation mechanism,which is determined by structure and amount of the thermal decomposition products,are described.During pyrolysis of polytrimethylene terephthalate,polymeric chain scissions take place a peeling reaction as a successive removal of the dimer units from the polymeric chain.The chain scissions are followed by the elimination reaction,linkage action and secondary reactions,which bring about a variety fragment.展开更多
基金supported by the Research Council of Payame Noor University
文摘This report describes a new three‐component strategy for the regioselective synthesis of a series of tri‐substituted pyridazines via a 1,4‐diazabicyclo[2.2.2]octane （DABCO）‐catalyzed condensation of propiophenones, arylglyoxalmonohydrates and hydrazine hydrate in water. This method provides a green and convenient one‐pot route toward a diverse set of 3,6‐diaryl‐4‐methylpyridazines bearing various aryl substituents. This procedure is highly regioselective, operationally simple, uses water as a safe, environmentally friendly solvent, and DABCO as a green base‐organocatalyst, and affords good to excellent yields of products.
文摘Pyrolysis of polytrimethylene terephthalate(PTT) fiber has been investigated by pyrolysis gas chromatography-mass spectroscopy in the temperature range from 400℃ to 750℃ in order to observe the possible effect of the temperature on its composition of pyrolysates.At 400℃,pyrolysis of molecular chain could occur,only 13 pyrolysates could be identified.The trimethylene moieties bound to the macromolecular core by ester bonds are cleaved at around 400℃.At 550℃-750℃,pyrolysis of molecular chain could completely take place,46 pyrolysates could be found.As the temperature increases,the compositions of pyrolysate are distinctly increased.Several compounds,especially benzoic acid,monopropenyl-p-phthalate,2-propenyl benzoate,di-2-propenyl ester,1,4-benzenedicarboxylic acid,benzene,1,5-hexadiene,biphenyl and 1,3-propanediol dibenzoate could be formed.The thermal degradation mechanism,which is determined by structure and amount of the thermal decomposition products,are described.During pyrolysis of polytrimethylene terephthalate,polymeric chain scissions take place a peeling reaction as a successive removal of the dimer units from the polymeric chain.The chain scissions are followed by the elimination reaction,linkage action and secondary reactions,which bring about a variety fragment.
