| abstract |
The immediate stoppage of a polyoxalkylation reaction in presence of a basic catalyst is effected by adding to the reaction mixt. (a) an alkylating agent, (b) a carboxylic acid halide, (c) a sulphonic acid halide, (d) a halogen deriv of methane and/or (e) a low mol.wt. organic cpd. contg. active halogen atoms. The blocking agents (one or more) are used to stop the polyaddn. of alkylene oxides (e.g. ethylene oxide) to low mol.wt. cpds. contg. active hydrogen (e.g. water, NH4OH, amines etc.) in presence of basic catalysts (e.g. Na methylate, KOH). Because of their rapid reaction, they prevent pollution of the atmosphere or possible explosion of the polymerisation vessel should the process get out of hand because of, e.g. too high a polymerisation temp. or pressure or too high an alkylene oxide content. |