Anic S.p.a.

Armando Mariano

Giorgio Mercati

Franco Cognigni

Antonio Glionna

Mario Ferri

Fulvio Pertot

Process for preparing diesterdiamides, consisting of reacting a diester with a diamine under wet conditions in the presence of suitable solvents and catalysts, to give the diester diamide, together with an ester salt derivative as impurity. The reaction product is then filtered to give a diesterdiamide cake and a mother solution of the reagents which also contains the solvent, the catalyst and the ester salt product. The cake is washed with a solvent of the ester salt, which also dissolves the reagents and catalysts. The mother solution and wash solution are then distilled, the two fractions obtained being recycled to the synthesis and to the wash.

Process for producing diesterdiamides

A flameproof linear polyester is described containing, copolymerized in the molecule, a phosphorus compound of formula: ##STR1## where R is a hydrogen atom, an alkyl group with 1 to 4 carbon atoms or a hydroxyalkyl group, and R' is a hydrogen atom, a hydroxyalkyl group or the group --(CH.sub.2 CH.sub.2 O).sub.n H, where n varies from 1 to 4. Said linear polyester is prepared by firstly forming a low molecular weight precondensate from a dicarboxylic aromatic acid (or a relative lower alkyl diester) and an alkylene glycol, and then polycondensing in the presence of said phosphorus compound, in such a quantity as to obtain a content of phosphorus (expressed as the metal) in the linear polyester of between 0.4 and 0.8% by weight. The linear polyester thus obtained can be formed into articles such as fibres, film, sheets and other articles which, besides being flameproof, possess improved dyeing characteristics. A process is also described for preparing the phosphorus compounds corresponding to the aforesaid general formula, where R is hydrogen or an alkyl group containing 1 to 4 carbon atoms, and R' is hydrogen. Said phosphorus compounds are prepared by reacting phenylphosphinic acid or ester with paraformaldehyde, at a temperature of between 60.degree. and 150.degree. C.

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Pisticci Scalo, Italy

Armando Mariano