Theoretical Studies on Mechanism and Rate Constant of Gas Phase Hydrolysis of Glyoxal Catalyzed by Sulfuric Acid
| Autor: | Zhenya Wang, Shunyou Cai, Yingmin Liao, Weixiong Zhao, Weijun Zhang, Mingqiang Huang, Changjin Hu |
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| Rok vydání: | 2016 |
| Předmět: |
Radical
Sulfuric acid 010501 environmental sciences 010402 general chemistry Photochemistry 01 natural sciences 0104 chemical sciences Catalysis Reaction rate chemistry.chemical_compound Hydrolysis Reaction rate constant chemistry Hydration reaction Physical chemistry Glyoxal Physical and Theoretical Chemistry 0105 earth and related environmental sciences |
| Zdroj: | Chinese Journal of Chemical Physics. 29:335-343 |
| ISSN: | 2327-2244 1674-0068 |
| DOI: | 10.1063/1674-0068/29/cjcp1509193 |
| Popis: | The gas phase hydration of glyoxal (HCOCHO) in the presence of sulfuric acid (H2SO4) were studied by the high-level quantum chemical calculations with M06-2X and CCSD(T) theoretical methods and the conventional transition state theory (CTST). The mechanism and rate constant of the five different reaction paths are considered corresponding to HCOCHO+H2O, HCOCHO+H2O⋯H2O, HCOCHO⋯H2O+H2O, HCOCHO+H2O⋯H2SO4 and HCOCHO⋯H2O+H2SO4. Results show that H2SO4 has a strong catalytic ability, which can significantly reduce the energy barrier for the hydration reaction of glyoxal. The energy barrier of hydrolysis of glyoxal in gas phase is lowered to 7.08 kcal/mol from 37.15 kcal/mol relative to pre-reactive complexes at the CCSD(T)/6-311++G(3df, 3pd)//M06-2X/6-311++G(3df, 3pd) level of theory. The rate constant of the H2SO4 catalyzed hydrolysis of glyoxal is 1.34×10−11 cm3/(molecule·s), about 1013 higher than that involving catalysis by an equal number of water molecules, and is greater than the reaction rate of glyoxal reaction with OH radicals of 1.10×10−11 cm3/(molecule·s) at the room temperature, indicating that the gas phase hydrolysis of glyoxal of H2SO4 catalyst is feasible and could compete with the reaction glyoxal+OH under certain atmospheric conditions. This study may provide useful information on understanding the mechanistic features of inorganic acid-catalyzed hydration of glyoxal for the formation of oligomer. |
| Databáze: | OpenAIRE |
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