Production of aromatic polyketones

A process for the production of an aromatic polyketone which comprises reacting at a temperature of from 40.degree. to 200.degree. C. in the presence of a quinquevalent phosphorous halide and a fluoroalkane sulphonic acid the reactants selected from the group consisting of:

• (a) a mixture of equimolar quantities of
• (i) at least one aromatic dicarboxylic acid of formula
• HO.sub.2 C--Ar--Co.sub.2 H
• where --Ar-- is a divalent aromatic radical and Co.sub.2 H is an aromatically bound carboxylic acid group, which acid is polymerisable with the at least one aromatic compound of (a)(ii),
• (ii) at least one aromatic compound of formula
• H--Ar'--H
• where --Ar'-- is a divalent aromatic radical and H is an aromatically bound hydrogen atom, which compound is polymerisable with the at least one aromatic dicarboxylic acid of (a)(i),
• (b) at least one aromatic monocarboxylic acid of formula
• H--Ar"--CO.sub.2 H
• where --Ar"-- is a divalent aromatic radical and H is an aromatically bound hydrogen atom and CO.sub.2 H is an aromatically bound carboxylic acid group, which acid is self-polymerisable, and
• (c) a combination of (a) and (b) said process being carried out with at least as many moles of phosphorous halide being used as are the number of moles of CO.sub.2 H groups used.