Abstract: Carboxylic acids are esterified with ethylene gas, to effect the formation of ethyl esters, by acid catalysis in the presence of at least one dissociating, inert and stable solvent which increases the acidity of the reaction medium.

Abstract: In a process for the preparation of ethyl acetate by vapor phase reaction of ethylene with acetic acid, the improvement which comprises conducting said reaction in the presence of a catalytic amount of a solid, ion-exchange fluoropolymer comprising sulfonic acid moieties.

Abstract: Carboxylic acids are esterified with ethylene or propylene gas, to effect the formation of ethyl or isopropyl esters, respectively, by acid catalysis in the presence of a catalytic amount of a perfluoro sulfonic acid.

Abstract: A thermosetting composition is disclosed characterized in that it comprises (by weight) from 60 to 90% of a bis-maleimide of the formula: ##STR1## in which A represents a divalent radical chosen from the group consisting of phenylene radicals and radicals of the formula: ##STR2## where T represents --CH.sub.2 --, --C(CH.sub.3).sub.2 --, --O-- or --SO.sub.2 --; and from 10 to 40% of N-vinylpyrrolid-2-one. The preferred bis-maleimide is N,N'-(4,4'-diphenylmethane)-bis-maleimide. The composition may be modified by the addition of an unsaturated polyester. The composition is useful for the manufacture of molded articles or of articles having a cellular structure, or for the impregnation of electrical coils.

Abstract: Polyamines possessing imide groups are obtained by heating at least one unsaturated polyimide of the general formula: ##STR1## WITH AT LEAST ONE POLYAMINE OF THE GENERAL FORMULA:Z(NH.sub.2).sub.bin which a and b each independently represents a number ranging from 2 to 6, Y represents an organic radical of valency a and Z represents an organic radical of valency b, in amounts such that the ratio of the number of NH.sub.2 groups introduced by the polyamine to the number of imide groups introduced by the polyimide is greater than 1 and at most equal to 5. These polyamines are useful for curing epoxy resins.

Abstract: A thermosetting composition is disclosed characterized in that it comprises (by weight) from 60 to 90% of a bis-maleimide of the formula: ##STR1## in which A represents a divalent radical chosen from the group consisting of phenylene radicals and radicals of the formula: ##STR2## where T represents --CH.sub.2 --, --C(CH.sub.3).sub.2 --, --O-- or --SO.sub.2 --; and from 10 to 40% of N-vinylpyrrolid-2-one. The preferred bis-maleimide is N,N'-(4,4'-diphenylmethane)-bis-maleimide. The composition may be modified by the addition of an unsaturated polyester. The composition is useful for the manufacture of molded articles or of articles having a cellular structure, or for the impregnation of electrical coils.

Abstract: A curable composition is provided which comprisesA. an imide group-containing compound which is eitherA. a bis-imide of the formula ##STR1## which D represents a radical of the formula ##STR2## in which Y represents H, CH.sub.3 or Cl, m is O or 1, and A represents a divalent organic radical containing 2 to 30 carbon atoms, orB. a mixture comprising a bis-imide of formula (I) and a mono-imide of the formula ##STR3## in which D is as defined above and R represents a hydrogen atom or a monovalent organic radical containing from 1 to 20 carbon atoms; andB. a polyurethane elastomer, in amounts such that the weight ratio ##EQU1## IS FROM 1/5 TO 4/1. Such compositions are useful for preparing moulded articles, adhesives, laminates and coatings.

Abstract: A polymer is disclosed that results from the reaction of:A. a polyimide of the formula: ##STR1## in which the symbol D represents a divalent radical selected from the class consisting of the radicals ##STR2## WHERE Y represents H, CH.sub.3 or Cl and m is 0 or 1, the symbol A represents an organic radical of valency n which may contain up to 30 carbon atoms, and n represents a number at least equal to 2;B. a polyamine of the formula(NH.sub.2).sub.p B (II)in which the symbol B represents an organic radical of valency p which may contain up to 30 carbon atoms, and p represents a number at least equal to 2; andC. a linear polyester, free from aliphatic unsaturation, and of molecular weight at least equal to 1,500, the amounts of these reactants being such that there are 1.2 to 5 imide groups per NH.sub.2 group, and the polyester represents up to 50% of the weight of the polyimide/polyamine/polyester combination. A process for making the polymer is also disclosed.

Abstract: Polymers possessing imide groups having excellent heat resistance and chemical inertness are disclosed. They are prepared by reacting cyanamide and a product possessing imide groups selected from:A. a bis-imide of the general formula: ##STR1## in which Q represents a divalent radical of the formula: ##STR2## WHEREIN Y represents H, CH.sub.3 or Cl and m is 0 or 1, and A represents a divalent organic radical containing 2 to 30 carbon atoms; andB. a mixture comprising a said bis-imide and a mono-imide of the general formula: ##STR3## in which Q is as defined above and R represents a hydrogen atom or a monovalent organic radical containing 1 to 20 carbon atoms.

Abstract: A cellular material is disclosed based on a polymer with imide groups, characterized in that it is obtained by heating a mixture comprising:A. a bis-maleimide of the formula ##STR1## in which the symbol B represents a phenylene radical or a radical of the formula ##STR2## where T represents --CH.sub.2 --, --O-- or --SO.sub.2 --; b. a furfuraldehyde derivative of the formula.SIGMA.-- R.sub.1 -- CO -- R.sub.1 --.SIGMA.'in which the symbol .SIGMA. represents a radical of the formula ##STR3## and the symbols R.sub.1 represent a valency bond or a --CH=CH-- group, and the symbol .SIGMA.' represents a radical .SIGMA., an aliphatic, cycloaliphatic or aromatic monovalent radical R containing up to 12 carbon atoms, or a --R'--CO--R" radical, where R' represents an aliphatic, cycloaliphatic or aromatic divalent radical containing up to 12 carbon atoms and R" represents a monovalent radical R or a radical .SIGMA.; andC. a blowing agent.

Abstract: Curable compositions are provided based on an imide group-containing compound, an amino compound and a polyurethane elastomer in specified proportions. These compositions can be cured to give articles possessing excellent impact strength.

Abstract: Polyamines possessing imide groups are obtained by heating at least one unsaturated polyimide of the general formula: ##STR1## WITH AT LEAST ONE POLYAMINE OF THE GENERAL FORMULA:Z(NH.sub.2).sub.bIn which a and b each independently represents a number ranging from 2 to 6, Y represents an organic radical of valency a and Z represents an organic radical of valency b, in amounts such that the ratio of the number of NH.sub.2 groups introduced by the polyamine to the number of imide groups introduced by the polyimide is greater than 1 and at most equal to 5. These polyamines are useful for curing epoxy resins.

Abstract: A suspension of a maleamic acid is provided by reacting maleic anhydride with an appropriate diprimary diamine in an organic diluent in the presence of a tertiary amine. The suspension has a low viscosity and the maleamic acid can readily be recovered from it.

Abstract: Polymers possessing imide groups are disclosed. These polymers display good impact strength and are obtained by reacting:A. a bis-imide of the formula ##EQU1## in which Y represents a divalent hydrocarbon radical with 2 to 20 carbon atoms which is free from unsaturated bonds other than aromatic bonds, a divalent mono- or bis-heterocyclic radical with 2 to 10 carbon atoms, or a divalent organic radical with 4 to 20 carbon atoms consisting of several of the hydrocarbon radicals defined above connected to one another by --O--, --S--, --CO-- or --SO.sub.2 --, andB. either an adduct (A) obtained by reacting an epoxy resin and a polyamine of the general formula:Z(-- NH.sub.2 ).sub.v (II)in which Z represents an organic radical of valency v and v represents an integer at least equal to 2, or a mixture comprising the adduct (A) and an amine of the formula:X NH.sub.2 ).sub.

Abstract: Multicellular polymers having excellent chemical inertness and heat resistance are produced by heating at a temperature from 100.degree. to 300.degree.C, maleic anhydride and a polyaldimine of the general formulaA (N = CH -- G).sub.n (I)in which G represents a monovalent organic radical which contains less than 35 carbon atoms and at least one aromatic or heterocyclic ring in the .alpha.-position to the imine group in formula (I), A represents an organic radical of valency n which contains less than 50 carbon atoms and at least one aromatic or heterocyclic ring in the .alpha.-position to the imine group in formula (I), and n represents a number at least equal to 2.

Abstract: Thermosetting polymers, both prepolymers and cured resins, are produced by reacting ammonia with a polyimide of the formula: ##EQU1## IN WHICH A IS A NUMBER FROM 2 TO 4, Y represents an organic radical of valency a, and A and T, which may be identical or different, each represent hydrogen, chlorine or methyl, the proportions of polyimide and ammonia being such that there are at least 2 imide groups per mol of ammonia. These polymers find utility in the production of materials liable to undergo severe heat stresses.

Abstract: Maleamic acids of formula: ##EQU1## where R is a divalent organic radical and X is H or NHCOCH=CHCOOH are prepared in suspension as a flowing non-thixotropic fluid by a process wherein a solution of a primary monoamine or diamine in a solvent is run into a solution of maleic anhydride in a solvent in an amount such that there is an anhydride excess of 5 to 20 mol % relative to the theoretical amount necessary for the reaction with the amine, the mixture is agitated, the reaction temperature is 40.degree. to 130.degree.C., the time taken to run in the amine solution is at least 67 minutes, and the amine solution is run in at a rate such that the slope of the curve representing the variation, as a function of time, in the rate of running in as % of the total amount of amine solution employed per minute (acceleration) has, at every point on this curve, a value not greater than 0.044.

Abstract: Bis-(4-furfurylidenamino-phenyl)-methane, m.p. 90.degree.-91.degree.C., is made by reacting furfural with bis-(4-aminophenyl)-methane in diethyl ether. It is useful in photography.