Gas products from the process of coal oxidization and spontaneous combustion have been studied at different temperatures with FTI spectroscopic tests. With temperatures rising to about 30~100 ℃, water and carbon diox...Gas products from the process of coal oxidization and spontaneous combustion have been studied at different temperatures with FTI spectroscopic tests. With temperatures rising to about 30~100 ℃, water and carbon dioxide gas were formed and from about 105~150 ℃, carbon monoxide was produced. Using the DFT B3LYP method with a 6-311G basis set, the reaction system, where spontaneous combustion between coal and oxygen occurs and produces water and monoxide, has been studied, with the geometric configuration for all stagnation points on the potential reaction energy surface optimized. With a frequency analysis and an IRC method, transient formations were tested. Our results indicate that in the reaction of coal oxidization and spontaneous com-bustion producing carbon dioxide and water, oxygen molecules attack carbon atoms of the terminal of the propyl alcohol group on the lateral chain of benzene rings, which causes this propyl alcohol group to produce the acid (-CH2-CH2-COOH) group and water. This acid group continues its break up into carbon dioxide and the (-CH2-CH3) ethyl group. We have come to the conclusion that this water-and-carbon dioxide-production reaction is spontaneous, based on the observation of the energy released by the reaction.展开更多
Second-order M ller-Plesset(MP2) and density functional theory(DFT) calculations have been carried out in order to investigate the structures and properties of dihydrogen-bonded CaH 2 HY(Y = CH 3,C 2 H 3,C 2 H,CN,and ...Second-order M ller-Plesset(MP2) and density functional theory(DFT) calculations have been carried out in order to investigate the structures and properties of dihydrogen-bonded CaH 2 HY(Y = CH 3,C 2 H 3,C 2 H,CN,and NC) complexes.Our calculations revealed two possible structures for CaH 2 in CaH 2 HY complexes:linear(I) and bent(II).The bond lengths,interaction energies,and strengths for H H interactions obtained by both MP2 and B3LYP methods are quite close to each other.It was found that the interaction energy decreases with increasing electron density at the Ca-H bond critical point.Atom-in-molecule(AIM) results show that for all of Ca-H H-Y interactions considered here,the Laplacian of the electron density at the H H bond critical point is positive,indicating the electrostatic nature of these Ca-H H-Y dihydrogen bonded systems.展开更多
基金Financial support for this work, provided by the National Natural Science Foundation of China (No.50834002)the National Eleventh Five-year Plan Science and Technology Key Project (No. 2006BAK03B05), is gratefully acknowledged
文摘Gas products from the process of coal oxidization and spontaneous combustion have been studied at different temperatures with FTI spectroscopic tests. With temperatures rising to about 30~100 ℃, water and carbon dioxide gas were formed and from about 105~150 ℃, carbon monoxide was produced. Using the DFT B3LYP method with a 6-311G basis set, the reaction system, where spontaneous combustion between coal and oxygen occurs and produces water and monoxide, has been studied, with the geometric configuration for all stagnation points on the potential reaction energy surface optimized. With a frequency analysis and an IRC method, transient formations were tested. Our results indicate that in the reaction of coal oxidization and spontaneous com-bustion producing carbon dioxide and water, oxygen molecules attack carbon atoms of the terminal of the propyl alcohol group on the lateral chain of benzene rings, which causes this propyl alcohol group to produce the acid (-CH2-CH2-COOH) group and water. This acid group continues its break up into carbon dioxide and the (-CH2-CH3) ethyl group. We have come to the conclusion that this water-and-carbon dioxide-production reaction is spontaneous, based on the observation of the energy released by the reaction.
基金supported by the General Programs of the Applied Basic Research of Science and Technology, Department of Yunnan Province(Nos.2008ZC095 and 2007B066M).
基金supported by the National Natural Science Foundation of China (20973076,20703021)the Basic Science Research Funding of Jilin University
文摘Second-order M ller-Plesset(MP2) and density functional theory(DFT) calculations have been carried out in order to investigate the structures and properties of dihydrogen-bonded CaH 2 HY(Y = CH 3,C 2 H 3,C 2 H,CN,and NC) complexes.Our calculations revealed two possible structures for CaH 2 in CaH 2 HY complexes:linear(I) and bent(II).The bond lengths,interaction energies,and strengths for H H interactions obtained by both MP2 and B3LYP methods are quite close to each other.It was found that the interaction energy decreases with increasing electron density at the Ca-H bond critical point.Atom-in-molecule(AIM) results show that for all of Ca-H H-Y interactions considered here,the Laplacian of the electron density at the H H bond critical point is positive,indicating the electrostatic nature of these Ca-H H-Y dihydrogen bonded systems.
