The reaction mechanism study on the decarbonylation of 2-methyl-2-propenal assisted by hydrogen chloride, water, or sulfur acid

摘要

The catalytic decarbonylation reaction mechanisms of 2-methyl-2-propenal in the presence of hydrogen chloride (HCl), water (H2O), or sulfuric acid (H2SO4) have been investigated theoretically for the first time. Both concerted and stepwise mechanisms have been considered. Compared with uncatalyzed reaction, the transition state energy is decreased by 90.46, 26.35, or 146.74 kJ/mol when the reaction is carried out with HCl, H2O, or H2SO4 as a catalyst, respectively. Our calculations demonstrate that the presence of HCl can reduce the transition state energy dramatically and make the decarbonylation of 2-methyl-2-propenal to be carried out at much lower temperatures, which is consistent with the experimental result. Moreover, the lowest activation energy assisted by H2SO4 suggests that H2SO4 may have better catalytic ability than that of HCl for the decarbonylation of 2-methyl-2-propenal, and our calculational results may be useful for future experimental studies on the title reaction.