First-principle Study On The Evolution Of Carbonyl Compounds In The Atmosphere

In this paper,we use the first principles calculation method and the transition state theory to study the evolution of carbonyl compounds in the atmosphere.The main research is divided into the following two aspects:?1?This paper mainly research on the reactions of Cl atom with carbonyl compound?CH₃?₂C?OH?C?O?CH₃ by quantum chemical methods and transition state theory.We explore four reaction pathways at the CCSD?T?-F12A/vdz-f12// BHand HLYP/6-311++G?d,p?level.The computational results show that the reaction has four reaction channels,that is,?CH₃?₂C?OH?C?O?CH₃ molecules have four different places of H atoms?H1,H2,H3,H4?can be extracted by Cl atoms,forming hydrogen bonds to obtain HCl.According to the results,the reaction barriers of four reaction pathways are-0.69?-1.31?7.45 and 0.13kcal/mol,respectively,which involve the lowest reaction barriers of-1.31kcal/mol.Based on the transition state theory,the reaction of the Cl atom with H2 atom in?CH₃?₂C?OH?C?O?CH₃ is major reaction pathways in the atmosphere.?2?The gas-phase hydrolysis of glycolaldehyde is of great interest for understating the atmospheric oxidation processes of glycolaldehyde.The mechanisms and kinetics of hydrolysis of CH₂OHCHO catalyzed by formic acid and sulfuric acid are theoretically investigated by using the CCSD?T?-F12a/VTZ-F12//M06-2X/6-311++G?3df,3pf?theoretical methods and canonical transition state theory with Eckart tunneling.We can from the theoretically information obtain result that the energy barrier of the hydrolysis of CH₂OHCHO,sulfuric acid as catalyst and acetic acid as catalyst is 39.47 kcal/mol,11.09 kcal/mol and 14.50 kcal/mol.It is show the free energy barrier of the transition starts involving catalysts are lowered to 28.38 kcal/mol and 24.97 kcal/mol.This shows that the hydrolysis reaction of H₂SO₄ and HCOOH on glycolaldehyde is a catalytic action,and from the thermodynamic point of view,H₂SO₄ is better than HCOOH catalytic effect.In addition,we have the traditional transition state theory to calculate the corrected Eckart tunneling rate channel,we can know from the kinetic reaction rate,access to CH₂OHCHO...H₂O+X?X=H₂SO₄,HCOOH?than into channel H₂O...X+CH₂OHCHO faster and more feasible...