Abstract: The invention relates to a method for producing carboxylic esters by converting a carboxylic acid or a carboxylic acid anhydride or a mixture thereof with an alcohol in a reaction system comprising one or more reactors, wherein reaction water is distilled as alcohol-water-azeotrope with the vapors, the vapors are at least partially condensed, the condensate is separated into an aqueous phase and an organic phase and said organic phase is supplied at least partially back into said reaction system. Components boiling lower than the alcohol are at least partially removed from said returned organic phase such as wherein components boiling lower than alcohol are evaporated and/or distilled off. An enrichment in the reaction system of by-products boiling lower than alcohol is avoided. Alcohol losses can be minimized by discharge currents.

Abstract: The invention relates to a method for producing carboxylic esters by converting a carboxylic acid or a carboxylic acid anhydride or a mixture thereof with an alcohol in a reaction system comprising one or more reactors, wherein reaction water is distilled as alcohol-water-azeotrope with the vapors, the vapors are at least partially condensed, the condensate is separated into an aqueous phase and an organic phase and said organic phase is supplied at least partially back into said reaction system. Components boiling lower than the alcohol are at least partially removed from said returned organic phase such as wherein components boiling lower than alcohol are evaporated and/or distilled off. An enrichment in the reaction system of by-products boiling lower than alcohol is avoided. Alcohol losses can be minimized by discharge currents.

Abstract: The invention relates to a method for producing carboxylic acid esters by reacting a reaction mixture, comprising a carboxylic acid and/or a carboxylic acid anhydride, and an alcohol in a reaction system having one or more reactors, wherein reaction water is distilled off as an alcohol/water azeotrope with the exhaust vapor. In addition, the reaction mixture is treated with superheated alcohol vapor. The method allows the production of esters having a low acid number.

Abstract: The invention relates to a method for producing carboxylic esters by converting a carboxylic acid or a carboxylic acid anhydride or a mixture thereof with an alcohol in a reaction system comprising one or more reactors, wherein reaction water is distilled as alcohol-water-azeotrope with the vapors, the vapors are at least partially condensed, the condensate is separated into an aqueous phase and an organic phase and said organic phase is supplied at least partially back into said reaction system. Components boiling lower than the alcohol are at least partially removed from said returned organic phase such as wherein components boiling lower than alcohol are evaporated and/or distilled off. An enrichment in the reaction system of by-products boiling lower than alcohol is avoided. Alcohol losses can be minimized by discharge currents.

Abstract: The invention relates to a raw ester of an esterification reaction catalyzed by a metal-containing esterification catalyst generated by a) mixing the raw ester at a temperature T of more than 100° C. under a pressure p that is equal to or greater than the vapor pressure of water at the temperature T with an aqueous base, b) relaxing the ester-base mixture and evaporating water, c) mixing the obtained fluid phase with water forming a water-in-oil emulsion, d) distilling water out of said emulsion and e) filtering the ester. Said method results in esters having low acid value and residues accrue in easily filterable form in the solid catalyst residues.

Abstract: The invention relates to a raw ester of an esterification reaction catalyzed by a metal-containing esterification catalyst generated by a) mixing the raw ester at a temperature T of more than 100° C. under a pressure p that is equal to or greater than the vapor pressure of water at the temperature T with an aqueous base, b) relaxing the ester-base mixture and evaporating water, c) mixing the obtained fluid phase with water forming a water-in-oil emulsion, d) distilling water out of said emulsion and e) filtering the ester. Said method results in esters having low acid value and residues accrue in easily filterable form in the solid catalyst residues.

Abstract: The invention relates to a method for producing carboxylic esters by converting a carboxylic acid or a carboxylic acid anhydride or a mixture thereof with an alcohol in a reaction system comprising one or more reactors, wherein reaction water is distilled as alcohol-water-azeotrope with the vapors, the vapors are at least partially condensed, the condensate is separated into an aqueous phase and an organic phase and said organic phase is supplied at least partially back into said reaction system. Components boiling lower than the alcohol are at least partially removed from said returned organic phase such as wherein components boiling lower than alcohol are evaporated and/or distilled off. An enrichment in the reaction system of by-products boiling lower than alcohol is avoided. Alcohol losses can be minimized by discharge currents.

Abstract: A process is described for preparing esters of an acid component selected from among polybasic C4-C10 carboxylic acids and an alcohol component selected from among C3-C12 alkanols or from among C3-C12 alkanediols, the alkyl chain of which may have interruption by from 1 to 3 oxygen atoms, by a) heating at boiling point, in a reaction zone and in the presence of an esterification catalyst, a mixture essentially consisting of the acid component or of an anhydride thereof and of the alcohol component, b) using rectification to separate the vapor comprising alcohol and water into an alcohol-rich fraction and a water-rich fraction, and c) returning the alcohol-rich fraction into the reaction zone and conducting the water-rich fraction out of the process. The process is simple to carry out and permits rapid achievement of essentially quantitative conversion.

Abstract: A process is described for preparing mixtures of diesters of phthalic acid with decanols and tridecanols by reacting phthalic acid or a reactive derivative of phthalic acid with a mixture made from at least one decanol and at least one tridecanol. Mixtures obtainable in this way are also described, as is their use as plasticizers for molding compositions, and also mixtures of isomeric tridecanols suitable for preparing the mixtures of diesters.

Abstract: Process for removal of the esterification catalyst by separation from a crude plasticizer ester obtained by reacting a dicarboxylic acid with C8–C13 alcohols, by treating the crude ester with an aqueous alkali solution in the range from 10 to 100° C. and then separating the aqueous alkaline phase comprising the hydrolyzed esterification catalyst by gravitational phase separation, by treating the crude ester, prior to or during the phase separation, with a salt of a di- or polyvalent metal, or with a mixture of these salts.

Abstract: Process for removal of the esterification catalyst by separation from a crude plasticizer ester obtained by reacting a dicarboxylic acid with C8-C13 alcohols, by treating the crude ester with an aqueous alkali solution in the range from 10 to 100° C. and then separating the aqueous alkaline phase comprising the hydrolyzed esterification catalyst by gravitational phase separation, by treating the crude ester, prior to or during the phase separation, with a salt of a di- or polyvalent metal, or with a mixture of these salts.

Abstract: The invention relates to a method for the production of phthalic anhydride to a specification, using a distillative purification of crude phthalic anhydride, by introduction of crude phthalic anhydride into a distillation column, operating at reduced pressure, withdrawal of the low-boiling fraction from the head, or near the head of the column and withdrawal of the phthalic anhydride, which meets the specification, from a side-tap on the column, whilst operating the column at a reflux ratio x, with 1:1.7<x<1:3.

Abstract: A process is described for preparing esters of an acid component selected from among polybasic C4-C10 carboxylic acids and an alcohol component selected from among C3-C12 alkanols or from among C3-C12 alkanediols, the alkyl chain of which may have interruption by from 1 to 3 oxygen atoms, by a) heating at boiling point, in a reaction zone and in the presence of an esterification catalyst, a mixture essentially consisting of the acid component or of an anhydride thereof and of the alcohol component, b) using rectification to separate the vapor comprising alcohol and water into an alcohol-rich fraction and a water-rich fraction, and c) returning the alcohol-rich fraction into the reaction zone and conducting the water-rich fraction out of the process. The process is simple to carry out and permits rapid achievement of essentially quantitative conversion.

Abstract: A process is described for preparing mixtures of diesters of phthalic acid with decanols and tridecanols by reacting phthalic acid or a reactive derivative of phthalic acid with a mixture made from at least one decanol and at least one tridecanol.

Abstract: Polyesters suitable as plasticizers and obtainable by reacting aliphatic dicarboxylic acids, neopentyl glycol, at least one other diol and a nonanol mixture, where the nonanol mixture is mainly composed of 1-nonanol, of monomethyloctanols, of dimethylheptanols and of monoethylheptanols. The nonanol mixture is also described, as is the use of the plasticizers.

Abstract: Polyesters suitable as plasticizers and obtainable by reacting aliphatic dicarboxylic acids, neopentyl glycol, at least one other diol and a nonanol mixture, where the nonanol mixture is mainly composed of 1-nonanol, of monomethyloctanols, of dimethylheptanols and of monoethylheptanols.

Abstract: The mixture described is a mixture of isomeric nonanol diesters of a dicarboxylic acid, selected from the class consisting of a mixture of diesters of adipic acid in the 1H NMR spectrum of which, observed in CDCl3, the ratio of the area under the resonance signals at chemical shifts in the range from 1.0 to 2.0 ppm with respect to TMS to the area under the resonance signals at chemical shifts in the range from 0.5 to 1.0 ppm with respect to TMS is from 1.20 to 5.00 and a mixture of diesters of phthalic acid, in the 1H NMR spectrum of which, observed in CDCl3, the ratio of the area under the resonance signals at chemical shifts in the range from 1.1 to 3.0 ppm with respect to TMS to the area under the resonance signals at chemical shifts in the range from 0.5 to 1.1 ppm with respect to TMS is from 1.00 to 4.00.

Abstract: A process for preparing esters from alcohol and carboxylic acid by a) feeding a mixture, comprising at least alcohol and/or carboxylic acid as educts, into a distillation column with separated sections containing reactive and conventional internals, wherein the reactive internals are arranged below the inlet of the mixture and conventional internals are arranged above the inlet of the mixture, b) reaction of the alcohol and the carboxylic acid in the reactive internals in presence of a catalyst, c) distillative separation of the evolving reaction mixture into the higher boiling ester and a lower boiling azeotrope containing alcohol, water and ester, wherein the ester accumulates in the bottom and the azeotrope is removed overhead, d) separation of the azeotrope in a phase separator in an aqueous phase and in an organic phase and the organic phase to be returned to the top of the column, wherein in step b) a heterogenous catalyst is utilized and in step c) the ester is taken off above the bottom as pure produc

Abstract: 4,4'-diaminobenzophenones of the formula I ##STR1## where the rings A and B can be further substituted, are prepared by a process in which a compound of the formula II ##STR2## where the rings A, B and E can be substituted, is oxidized with aqueous nitric acid in the presence of nitrobenzene or of an alkanoic acid and under superatmospheric pressure, and the reaction product is cleaved.The process according to the invention gives the compounds of the formula I in high yield and purity.

Abstract: Pure monoesters of adipic acid are prepared by a process in which(a) a pentenoate is reacted with carbon monoxide and hydrogen at from 90.degree. to 140.degree. C. and under from 5 to 300 bar in the presence of a carbonyl complex of cobalt or of rhodium, and a 5-formylvalerate is separated off, and(b) the 5-formylvalerate thus obtained is oxidized with molecular oxygen, or with a gas containing this, at from 20.degree. to 100.degree. C. under from 1 to 10 bar.