The pyrolysis reaction of acrylonitrile(AN)/N-vinylpyrrolidone(N-VP) copolymer in air was studied with DSC. The apparent activation energy of pyrolysis reaction of copolymer was calculated by the Kissinger method. The...The pyrolysis reaction of acrylonitrile(AN)/N-vinylpyrrolidone(N-VP) copolymer in air was studied with DSC. The apparent activation energy of pyrolysis reaction of copolymer was calculated by the Kissinger method. The effect of different copolymerization conditions on the apparent activation energy of copolymer was discussed. It was found that with an increase of DMSO concentration in mixture solvent,the degradation apparent activation energy rose rapidly. When the weight ratio of N-VP/AN was less than 5/95, the apparent activation energy of degradation reduced quickly with the comononer N-VP concentration rising, and when the ratio was more than 5/95, the apparent activation energy became almost constant. When the copolymerization temperature rose, the apparent activation energy also increased.展开更多
Density functional theory (DFT) and ab initio methods were used to study gas phase pyrolytic reaction mechanisms of N ethyl, N isopropyl and N t butyl substituted 2 aminopyrazine at B3LYP/6 31G ...Density functional theory (DFT) and ab initio methods were used to study gas phase pyrolytic reaction mechanisms of N ethyl, N isopropyl and N t butyl substituted 2 aminopyrazine at B3LYP/6 31G * and MP2/6 31G *, respectively. Single point energies of all optimized molecular geometries were calculated at B3LYP/6 311+G(2d,p) level. Results show that the pyrolytic reactions were carried out through a unimolecular first order mechanism which were caused by the migration of atom H(17) via a six member ring transition state. The activation energies which were verified by vibrational analysis and correlated with zero point energies along the reaction channel at B3LYP/6 311+G(2d,p) level were 252.02 kJ·mol -1 ( N ethyl substituted), 235.92 kJ·mol -1 ( N isopropyl substituted) and 234.27 kJ·mol -1 ( N t butyl substituted), respectively. The results were in good agreement with available experimental data.展开更多
文摘The pyrolysis reaction of acrylonitrile(AN)/N-vinylpyrrolidone(N-VP) copolymer in air was studied with DSC. The apparent activation energy of pyrolysis reaction of copolymer was calculated by the Kissinger method. The effect of different copolymerization conditions on the apparent activation energy of copolymer was discussed. It was found that with an increase of DMSO concentration in mixture solvent,the degradation apparent activation energy rose rapidly. When the weight ratio of N-VP/AN was less than 5/95, the apparent activation energy of degradation reduced quickly with the comononer N-VP concentration rising, and when the ratio was more than 5/95, the apparent activation energy became almost constant. When the copolymerization temperature rose, the apparent activation energy also increased.
文摘Density functional theory (DFT) and ab initio methods were used to study gas phase pyrolytic reaction mechanisms of N ethyl, N isopropyl and N t butyl substituted 2 aminopyrazine at B3LYP/6 31G * and MP2/6 31G *, respectively. Single point energies of all optimized molecular geometries were calculated at B3LYP/6 311+G(2d,p) level. Results show that the pyrolytic reactions were carried out through a unimolecular first order mechanism which were caused by the migration of atom H(17) via a six member ring transition state. The activation energies which were verified by vibrational analysis and correlated with zero point energies along the reaction channel at B3LYP/6 311+G(2d,p) level were 252.02 kJ·mol -1 ( N ethyl substituted), 235.92 kJ·mol -1 ( N isopropyl substituted) and 234.27 kJ·mol -1 ( N t butyl substituted), respectively. The results were in good agreement with available experimental data.
