Non-empirical calculations for minimal energetic reaction pathways of hf molecule addition to acetylene and methylacetylene

• Main Authors: Yu. B. Kirillov, N. M. Klimenko
• Format: Article
• Language: Russian
• Published: MIREA - Russian Technological University 2009-02-01
• Series: Тонкие химические технологии
• Subjects: gas-phased reactions; electrophile; nucleophile; acetylene; methylacetylene; alkynes; non-empirical harthree-fock-ruthane method; gaussian-03; electronic correlation; markovnikov's rule; transition state; reaction heat; activation energy
• Online Access: https://www.finechem-mirea.ru/jour/article/view/1125
• ISSN: 2410-6593; 2686-7575

Potential energy surfaces of gas-phased synchronous addition of HF to acetylene and methylacetylene. A non-empirical Harthree-Fock-Ruthane method (Gaussian-03, G-31++G** basis) with electronic correlation consideration in MP2 approximation (Moeller-Plesseth 2nd grade) was used. Reaction heats and activation energies were calculated. Reaction heat of HF addition to acetylene molecule is -19.5 kcal/mol, activation energy is 52.3 kcal/mol. Reaction heats of HF addition to methylacetylene according to Markovnikov's rule and against it comprise -20.7 and -16.1 kcal/mol; activation energies are 48.0 and 53.5 kcal/mol accordingly. It was established that HF addition to methylacetylene molecule with formation of 2-fluoropropene is more energetically advantageous according to Markovnikov's rule kinetically as well as thermodynamically.