Abstract: Alkali metal ions are separated off from alkoxylates containing alkali metal ions by a process comprising: a) dilution of the alkali metal-containing alkoxylate with an inert solvent, b) treatment of the alkali metal-containing solution of the alkoxylate with a cationic exchanger in order to obtain a substantially alkali metal-free solution of the alkoxylate, and c) removal of the solvent from the substantially alkali metal-free solution of the alkoxylate in order to obtain a substantially alkali metal-free and substantially solvent-free alkoxylate.

Abstract: A process for preparing bisphenol alkoxylates comprises reacting at least one bisphenol with alkylene oxide in the presence of a phosphine catalyst which is essentially free of alkali metal hydroxide.

Abstract: Alkali metal ions are separated off from alkoxylates containing alkali metal ions by a process comprising:

Abstract: In a process for isolating alkylene glycol having a low aldehyde content, in which a mixture comprising alkylene glycol is subjected to a final distillation, formic acid or a formate or a mixture of two or more formates or a mixture of formic acid and one or more formates is present in the mixture comprising alkylene glycol.

Abstract: A process for the continuous production of 1,3-dioxolan-2-ones such as ethylene carbonate or propylene carbonate by reacting a corresponding oxirane with carbon dioxide in the liquid phase in the presence of a catalyst comprises conducting the reaction in a two-part reactor in whose first part the reaction is taken with backmixing to a conversion of not less than 80% of the oxirane II and in whose second part the reaction is completed under nonbackmixing conditions, and passing the carbon dioxide in countercurrent to the oxirane II in the entire reactor.

Abstract: In a process for preparing alkoxylated amines or alcohols in which a reaction mixture comprising an amine or an alcohol or a mixture of two or more amines and/or alcohols and an alkylene oxide, or a mixture of two or more different alkylene oxides, is reacted in one or more successive reaction steps, at least one of the reaction steps is carried out in the presence of a basic catalyst and, in at least one of the reaction steps, formic acid or a salt of formic acid or a mixture of two or more thereof is present in the reaction mixture or the reaction mixture is admixed with formic acid or a salt of formic acid, or a mixture of two or more thereof, after the alkoxylation is complete. The alkoxylates prepared by the process of the present invention have a light color and a low odor.

Abstract: Crude (meth)acrylic acid is purified by a process in which a primary amine compound and an organic sulfonic acid are added to the crude (meth)acrylic acid and the latter is then worked up by distillation.

Abstract: In a process for the continuous preparation of alkyl esters of (meth)acrylic acid by reacting (meth)acrylic acid with alkanols having from 1 to 8 carbon atoms in a homogeneous, liquid, solvent-free phase at elevated temperature and in the presence of an acid esterification catalyst, in which the (meth)acrylic acid, the alkanol and the acid catalyst are fed to a reaction zone, the water formed is removed by rectification during a residence time as constituent of a mixture comprising starting alkanol in a rectification unit (III) superposed on the reaction zone, the distillate obtained is separated into an organic phase comprising alkanol and an aqueous phase comprising water, the organic phase is essentially completely returned to the rectification unit (III), the reaction mixture is discharged from the reaction zone and conveyed into a distillative separation zone comprising further rectification units and in the latter the alkyl (meth)acrylate formed is separated off.

Abstract: In a process for preparing .omega.-hydroxyesters of .alpha.,.beta.-unsaturated carboxylic acids, a vinyloxy ester of the carboxylic acid is treated with a strong acid in the presence of an alcohol, in particular a 1,2-diol or 1,3-diol.

Abstract: In a process and an apparatus for the continuous preparation of alkyl esters of (meth)acrylic acid by reacting (meth)acrylic acid and monohydric alkanols of 1 to 8 carbon atoms in the homogeneous, liquid, solvent-free phase at elevated temperatures and in the presence of an acidic esterification catalyst, by feeding the (meth)acrylic acid, the alkanol and the acid catalyst continuously to a reaction zone, the reaction zone consists of a cascade of at least two reaction regions connected in series, and the discharge stream of one reaction region forms a feed stream of a downstream reaction region. The cascade may have from two to four reaction regions is spatially separated from one another.

Abstract: In the process for the continuous preparation of alkyl esters of (meth)acrylic acid by reacting (meth)acrylic acid with monohydric alkanols having from 1 to 8 carbon atoms in the presence of an acid esterification catalyst in a reaction zone, there is discharged from the reaction zone a product mixture which comprises the alkyl (meth)acrylate formed, the catalyst and the by-products formed during the course of the esterification having boiling points higher than that of the alkyl (meth)acrylate, and from which the alkyl (meth)acrylate is separated by distillation in a separation zone. The product mixture discharged from the reaction zone is fed to a rectification unit (I), in this unit the product mixture discharged is separated by rectification into at least one product (I) comprising the alkyl ester of (meth)acrylic acid and a product (II) comprising the catalyst, the product (I) is fed to a further rectification unit (II) and in this the alkyl ester of (meth)acrylic acid is separated off by rectification.

Abstract: A process for preparing substituted imidazoles of the formula I ##STR1## R.sup.1, R.sup.2 and R.sup.3 are identical or different and are each hydrogen, halogen, NO.sub.2, CN or a C.sub.1 -C.sub.20 -hydrocarbon radical which is unsubstituted or substituted by one or more halogens or R.sup.1 and R.sup.2 together are members of a 3- to 20-membered hydrocarbon ring which is unsubstituted or substituted by one or more halogens and/or C.sub.1 -C.sub.8 -alkyl groups and which may contain 1, 2 or 3 heteroatoms from the group consisting of nitrogen, oxygen and sulfur, andR.sup.4 is a C.sub.1 -C.sub.20 -hydrocarbon radical which is unsubstituted or substituted by one or more halogens,comprises using an aqueous phase of the imidazoles of the formula II ##STR2## where R.sup.1, R.sup.2 and R.sup.3 are as defined above with compounds of the formula IIIR.sup.4 --O--R.sup.5 IIIwhereR.sup.4 is as defined above andR.sup.5 is hydrogen or R.sup.4, it being possible in the latter case for the two R.sup.

Abstract: A process for preparing acrylic acid and/or esters comprises the steps of:(a) catalytic gas phase oxidation of propene and/or acrolein to acrylic acid to obtain a gaseous reaction product comprising acrylic acid,(b) solvent absorption of the reaction product,(c) distillation of the solvent loaded with acrylic acid to obtain a crude acrylic acid and the solvent,(d) purification of the crude acrylic acid by crystallization and(e) optionally esterification of the crystalline acrylic acid.

Abstract: In a process and an apparatus for the continuous preparation of alkyl esters of (meth)acrylic acid by reacting (meth)acrylic acid and monohydric alkanols of 1 to 8 carbon atoms in the homogeneous, liquid, solvent-free phase at elevated temperatures and in the presence of an acidic esterification catalyst, by feeding the (meth)acrylic acid, the alkanol and the acid catalyst continuously to a reaction zone, the reaction zone consists of a cascade of at least two reaction regions connected in series, and the discharge stream of one reaction region forms a feed stream of a downstream reaction region. The cascade may have from two to four reaction regions spatially separated from one another.

Abstract: The continuous esterification of a C.sub.1 -C.sub.8 -alkanol with (meth)acrylic acid in a molar ratio of from 1:1 to 2:1 in the presence of proton-donating catalysts in a homogeneous, liquid, solvent-free phase, in which the water of reaction and resulting alkyl (meth)acrylate are separated off continuously as part of an aqueous azeotropic mixture via the top of a rectification zone attached to the reaction zone, at a top pressure of from 0.1 to 1 atm, and worked up to give pure (meth)acrylate, is carried out by a process wherein the reaction temperature is from 100.degree. to 150.degree. C., the residence time is from 1 to 5 hours and from 5 to 20% by weight, based on the amount of reaction mixture, of sulfuric acid or an equimolar amount, based on such an amount of sulfuric acid, of an organic sulfonic acid is added as a protic acid catalyst to the reaction mixture present in the reaction zone.

Abstract: A diester of (meth)acrylic acid with a C.sub.4 -C.sub.6 -alkanediol is separated from a mixture which essentially consists of the C.sub.4 -C.sub.6 -alkanediol, the monoester of (meth)acrylic acid with the C.sub.4 -C.sub.6 -alkanediol and the diester of (meth)acrylic acid with the C.sub.4 -C.sub.6 -alkanediol by extraction with an organic solvent in the presence of water, by a process in which the diester-containing mixture is added continuously in the middle section of an extraction column and in addition water and the organic extracting agent are passed continuously countercurrent in the extraction column.

Abstract: 1,4-butanediol mono(meth)acrylate is prepared by esterification of (meth)acrylic acid with 1,4-butanediol, by a process in which an aqueous solution of unconverted 1,4-butanediol is obtained, wherein the 1,4-butanediol present in the aqueous solution is converted into readily volatile tetrahydrofuran in the presence of a catalytic amount of a strong acid and the tetrahydrofuran is separated off from the aqueous solution.

Abstract: A process for the separation of a mono(meth)acrylate of a C.sub.4 -C.sub.6 alkanediol from an aqueous solution containing a mono(meth)acrylate of a C.sub.4 -C.sub.6 alkanediol and the said C.sub.4 -C.sub.6 alkanediol, by extraction with an organic solvent, in which the extracting agent used is an organic solvent selected from the group comprising esters of C.sub.1 -C.sub.4 alkanecarboxylic acids and C.sub.1 -C.sub.5 alkanols, single and mixed dialkyl ethers having from 4 to 8 C atoms, and mixtures of such organic solvents.

Abstract: N-substituted-pyrazoles of the formula ##STR1## wherein R.sup.1 is C.sub.1 -C.sub.12 -alkyl or C.sub.7 -C.sub.20 -alkyl, and R.sup.2, R.sup.3 and R.sup.4 independently denote hydrogen, C.sub.1 -C.sub.12 -alkyl, phenyl, C.sub.7 -C.sub.20 -alkylphenyl and C.sub.7 -C.sub.20 -phenylalkyl, are prepared by reacting a pyrazole of the formula ##STR2## wherein R.sup.2, R.sup.3 and R.sup.4 have the meanings above, with an alcohol or ether of the formulaR.sup.1 --O--R.sup.5 III,wherein R.sup.5 is hydrogen or R.sup.1, at a temperature of from 200.degree. to 550.degree. C. and a pressure of from 0.001 to 50 bar in the presence of a heterogeneous catalyst, preferably one which contains acid centers such as the oxides of aluminum, silicon, titanium and/or zirconium, optionally doped with phosphoric acid.

Abstract: A process for breaking down aromatic nitro compounds in waste waters from plants for the production of nitrobenzene by treatment with nitric acid is carried out at from 180.degree. to 350.degree. C. and under a pressure of from 40 to 250 bar.