GB1026802A - Improved process for the production of polyaldehydes - Google Patents

Abstract

Saturated aldehydes are polymerized in the presence of an alkali metal catalyst, as defined below, at a temperature below that at which the catalyst also acts as a catalyst to degrade the polymeric product and after the polymerization is completed and before the reaction medium reaches a temperature at which substantial degradation of the polymeric aldehyde may occur, a weak acid is added to the reaction medium in an amount at least equivalent to the amount of catalyst present. The alkali metal catalysts referred to above are the metals, the simple and complex metal hydrides and compounds in which the metal atom is linked to a hydrocarbon group, an oxyhydrocarbon group or a substituted derivative of such groups. Of a number of catalysts listed sodium methoxide, sodium ethoxide, potassium t-butoxide and sodium cyclohexoxide are exemplified. Suitable aldehydes are aliphatic aldehydes, cycloaliphatic aldehydes, aromatic aldehydes and their substituted derivatives, preferably containing up to 10 carbon atoms. Of the suitable organic and inorganic weak acids listed, n-butyric acid is exemplified. The polymerization may be carried out in an organic solvent such as alkenes, alkanes or dialkyl ethers, pentane being exemplified. The polymerization is preferably carried out at temperatures below - 60 DEG C., and may be effected in an inert atmosphere, e.g. nitrogen, and at atmospheric pressure or at sub- or super-atmospheric pressures. Thermal instability of the formed polymers may be reduced by subsequently replacing their terminal hydroxyl groups with carboxylate groups and may, by thereafter subjecting to a heat treatment (as described in Specification 980,516) be further reduced.