Abstract: An acetal or a ketal are prepared by reacting a carbonyl compound and an alcohol in the presence of an acid catalyst and water. Water and alcohol are removed from the reaction mixture in an at least two-stage pervaporation or vapor permeation process using a plurality of membranes. Additional alcohol is fed into a retentate stream of at least one of the two stages. At least one of the plurality of membranes in the two-stage pervaporation or vapor permeation process is different from the other membranes in terms of selectivity behavior in the removal of water and alcohol.

Abstract: Molding compounds which contain a thermoplastically processible aromatic polyester imide prepared by polymerizing: (A) 0 to 70 mole % of HO-Ar-COOH; (B) 0 to 44 mole % of HOOC-Ar'-COOH; (C) 15 to 45 mole % of HO-Ar"-OH; and (D) 1 to 45 mole % of a compound having the general structure: ##STR1## are readily processed, possess good mechanical properties and are useful for the production of molded articles.

Abstract: A molding compound, comprising a thermoplastically processible, aromatic polyester imide containing monomer units corresponding to the following starting monomers:(A) 10-70 mole % HO--Ar--COOH(B) 0-44 mole % HOOC-Ar'--COOH(C) 15-45 mole % HO--Ar"--OH, and(D) 1-45 mole % of a compound having the structure ##STR1## wherein Ar, Ar' and Ar" are the same or different; and are 1,3- or 1,4-phenylene; 1,4-, 1,5-, 2,6- or 2,7-naphthylene or ##STR2## Y is --O-- or --S--; X is --O--, --S--, --SO.sub.2 --, --CR.sub.2 --, or --CO--; R is H, C.sub.1 -C.sub.4 -alkyl; and n is 0 or 1; and wherein all quantities relate to the sum of A-D, and said sum equals 100 mole %, whereby the molar ratio of (B+D): C ranges from 0.9:1 to 1.1:1.

Abstract: A molding material, comprising the following monomer units:(A) 10-80 mole % HO--AR--COOH,(B) 0-40 mole % HOOC--Ar'--COOH,(C) 10-45 mole % HO--Ar"--OH, and(D) 5-45 mole % ##STR1## wherein Ar, Ar', and Ar", independently, are 1,3- or 1,4-phenylene; 1,4-, 1,5-, 2,6- or 2,7-naphthylene or ##STR2## wherein X is --O--, --S--, --SO.sub.2 -- or --CR.sub.2 --, R is H or C.sub.1-4 alkyl, and n is 0 or 1, wherein all monomer unit quantities relate to the sum of components A-D and their sum is 100 mol %, and wherein the molar ratio (B+D):C ranges from about 0.9:1 to 11.1:1.

Abstract: Aromatic polyesters based on phenoxyterephthalic acid, a method of manufacturing the same, and applications of the same. The inventive polyesters are based on phenoxyterephthalic acid, one or more other aromatic dicarboxylic acids, a dihydroxyaryl compound (with 2 OH groups attached to an aromatic ring), and an hydroxyaromatic carboxylic acid, are partially crystalline, form an anisotropic melt phase, and are processible at up to 360.degree. C. The polyesters may be used for manufacturing pieces formed by molding, extrusion, or other standard forming techniques.

Abstract: A thermotropic aromatic polyester molding compound, comprising:(A) 10-80 mol % p-Hydroxybenzoic acid;(B) 10-45 mol % HOOC-Ar-COOH;(C) 0-43 mol % HO-Ar'-OH, where Ar and Ar' are, independently, 1,3- or 1,4-phenylene; 1,4-, 1,5-, 2,6- or 2,7-naphthalene; or ##STR1## wherein X is --O--, --S--, --SO.sub.2, --CR.sub.2 --; n is 0 or 1 and R is H or C.sub.1-4 alkyl; and(D) 2-45 mol % ##STR2## wherein Y is --H, --R, --OR, --Ar", or --OAr", where Ar" is a monovalent aromatic group; andwherein the molar ratio B/(C+D) is in the range 0.9:1 to 1.1:1.