Quantum chemical investigation by the AM1 method of the catalytic cyclodehydration of 1,4-butanediol

1,4-Butanediol is converted into tetrahydrofuran in the presence of silica gel at temperatures of 245–340°C. The mechanism of the conversion of 1,4-butanediol has been studied by the quantum chemical AM1 method with full optimization of the geometry. It was established that two parallel reactions are possible depending on the conformation of the molecule. The cyclodehydration reaction is effected by conversion of a semicyclic conformer of the protonated diol molecule at a basic center of the catalyst by a concerted mechanism. The heat of the reaction forming tetrahydrofuran is —161.768 kcal/mole.Latvian Institute of Organic Synthesis, Riga LV-1006. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 608–613, May, 1998.