PROCESS FOR THE PREPARATION OF ALUMINUM OXIDE CARBOXYLATE POLYMERS CONTAINING AT MOST TWO PERCENT BY WEIGHT OF ESTER

The invention relates to a novel process for the preparation of aluminum oxide carboxylate polymers containing at most 2% by weight of ester by reacting an aluminum alkoxide of the general formula Al(OR)3, wherein R stands for a C2-5 alkyl group, dissolved in an aromatic or aliphatic hydrocarbon with a solution of a C8-22 aliphatic or alicyclic monocarboxylic acid or carboxylic acid mixture and water in a C2-5 alkanol and removing the alkanol(s). The process according to the invention comprises introducing the solution of the aluminum alkoxide to a tube reactor having a 10 to 200 length/diameter ratio at a temperature exceeding by 15 DEG to 50 DEG C. the boiling point of the higher boiling alkanol among that corresponding to the alkanol component of aluminum alkoxide and that used as solvent; then feeding in the alkanolic solution containing the monocarboxylic acid and water, wherein the aluminum/monocarboxylic acid mole ratio is at least 10:1 and the aluminum/water mole ratio is at least 10:1; removing the alkanol formed in the reaction; returning the reaction mixture into the tube reactor; repeating this operation until the mono-carboxylic acid/aluminum mole ratio reaches 0.95 to 1.05 and the water/aluminum mole ratio reaches 0.9 to 1.0; and then making the product obtained free from alkanol.