Abstract: An improved method for recovery of alkali metal or alkaline-earth metal terephthalate and of alkylene glycol, from polyalkylene terephthalate, in particular from polyethylene terephthalate (P.E.T.), alkylene glycol, in particular ethylene glycol produced in the form of vapor during the saponification reaction, initiated by the action of intensive kneading of polyalkylene terephthalate and the alkaline reagent at a temperature of 100.degree. to 200.degree. C. The alkylene glycol is recovered in gaseous form by entrainment by an inert gas or by extraction under low pressure. The alkaline terephthalate or alkaline-earth terephthalate is obtained in solid or powder form; it can easily be stored, transported and redissolved, in order to be purified and possibly transformed into terephthalic acid or ester.

Abstract: In the preparation of miceller systems for enhanced hydrocarbon recovery, surfactants are used which consist of N-acyl N-alkyl-.alpha.-amino-carboxylic compounds. The considered products comply with the general formulas: ##STR1## wherein at least one of R.sup.1, R.sup.2 and R.sup.3 is a saturated or unsaturated C.sub.1 -C.sub.22 aliphatic hydrocarbon radical (one of them having optionally a carboxylic group) the other or others being a hydrogen atom, R.sup.1, R.sup.2 and R.sup.3 having together from 4 to 22 carbon atoms, R.sup.4 is an alkyl radical of 1-5 carbon atoms, R.sup.5 an alkyl radical of 1-12 carbon atoms and M is an alkali or alkaline-earth metal, ammonium or a quaternary ammonium group.As used in the formation of micellar systems (aqueous solutions, emulsions or mirco-emulsions) for enhanced oil recovery, these surfactants have improved performances, particularly, in field waters of high polyvalent ion (Ca.sup.++ and Mg.sup.++) content, within relatively wide temperature and pH ranges.

Abstract: A dicarboxylic compound complying with one of the general formulae: ##SPC1##In which R is a divalent radical selected from the aliphatic, alicyclic and aromatic radicals, the aliphatic containing 1-20 carbon atoms and the other containing from 5 to 20 carbon atoms, R.sup.1 is selected from the hydrogen atom and the alkyl and cycloalkyl groups containing from 1 to 10 carbon atoms and R.sup.2 is selected from the alkyl and cycloalkyl groups containing from 1 to 10 carbon atoms, the polyester resins derived therefrom being usable as enamelling composition, particularly for coating metal wires.