Mechanisms of formation of hemiacetals: intrinsic reactivity analysis.

摘要: The reaction mechanism of the hemiacetal formation from formaldehyde and methanol has been studied theoretically at B3LYP/6-311++G(d,p) level. In addition to study between isolated reactants, three different kinds catalysis have explored. first one examines use assistants, especially bridging water molecules, in proton transfer process. second attempts increase local electrophilicity carbon atom with presence a Bronsted acid (H(+) or H(3)O(+)). last considers combined effect both catalytic strategies. force, electronic chemical potential, flux characterized for path each case. general, it found that structural rearrangements represent an important energetic penalty during activation barriers reactions catalyzed by acids show high percentage reorganization contribution. effects assisted molecules are due reduction strain transition state structures. includes assistance shows lowest energy barrier (25.0 kJ mol(-1)).