Low molecular poly:hydroxy cpds. prodn. - by condensn. of formaldehyde over lead-contg. catalyst and co-catalyst under controlled pH conditions

摘要

Prodn. of mixts. of low mol. polyhydroxy cpds. (I) and opt. hydroxy-aldehydes (II) and hydroxyketones (III) comprises condensn. of HCHO in the presence of Pb (II) cpds. as catalyst and of cocatalysts contg. a mixt. of (II) and (III). In the parent patent, the soln. is kept at pH 6.0-7.0 by controlled addn. of an (in)organic base until the conversion is 10-60% and then at 4.0-6.0. The novelty is that, in the second phase of condensn., the pH is 0.5-3, pref. 0.8-1.7 units lower than that in the first phase. The catalyst pref. is a soluble Pb (II) salt.