Abstract: The invention relates to a reducing agent for the soluble chromate content of cement and to methods for the production thereof, which comprise concentrating an used sulfuric acid, containing iron (II) sulfate, and separating the sulfuric acid from the obtained precipitate which contains iron (II) sulfate.

Abstract: The invention relates to a reducing agent for the soluble chromate content of cement and to methods for the production thereof, which comprise concentrating an used sulfuric acid, containing iron (II) sulfate, and separating the sulfuric acid from the obtained precipitate which contains iron (II) sulfate.

Abstract: The invention relates to a reducing agent for the soluble chromate content of cement and to methods for the production thereof, which comprise concentrating an used sulfuric acid, containing iron(II) sulfate, and separating the sulfuric acid from the obtained precipitate which contains iron(II) sulfate.

Abstract: The invention relates to a process for preparing sorbic acid by thermal cleavage in a solvent of the polyester prepared from crotonaldehyde and ketene, the cleavage of the polyester being carried out in the presence of 20 to 100% by weight of a secondary or tertiary aliphatic, alicyclic nitrogen- and/or oxygen-containing amine, or aliphatic-aromatic substituted amine, as catalyst.

Abstract: The invention relates to a process for preparing sorbic acid by cleaving the sorbic acid polyester prepared from crotonaldehyde and ketene, the sorbic acid polyester being distilled and the cleavage being catalyzed by an amine, which comprises separating off the amine from the distillation residue by distillation under reduced pressure and at a temperature which is higher than the temperature of the polyester distillation and recovering it.

Abstract: The invention relates to a process for preparing sorbic acid by thermal cleavage in a solvent of the polyester prepared from crotonaldehyde and ketene, the cleavage of the polyester being carried out in the presence of 20 to 100% by weight of a secondary or tertiary aliphatic, alicyclic nitrogen- and/or oxygen-containing amine, or aliphatic-aromatic substituted amine, as catalyst.

Abstract: A compound of the formula I, ##STR1## in which X is F, Cl or Br,R is alkyl having from 1 to 5 carbon atoms, aryl, aryloxy or aralkyl andn is an integer from 1 to 5, a plurality of R representing equal or different of said substituents and a process for preparing them.

Abstract: Tertiary aromatic phosphine oxides of the formula ##STR1## in which X=F, Cl or Br, are prepared by Friedel-Crafts reaction of (a) phenylthiophosphonic dichloride with fluoro-, chloro-or bromobenzene, or(b) of dichlorophenylphosphine, sulfur and fluoro-, chloro-or bromobenzene, and(c) subsequent conversion of the phosphine sulfides produced by (a) or (b) using H.sub.2 O.sub.2 in a solvent which comprises at least about 2% by weight, preferably at least about 10% by weight, of optionally halogenated lower aliphatic carboxylic acids and/or their anhydrides and, if appropriate, of other inert solvents which are miscible therewith.The reaction products are final products and intermediates in various specialized fields, such as, for example, in the plant protection sector and the polymers sector.

Abstract: Tertiary phosphine oxides are prepared by oxidation of tertiary phosphine sulfides using H.sub.2 O.sub.2 in a solvent comprising about 2-20% by weight of optionally halogenated lower aliphatic carboxylic acids and the remainder of mono- or polyhydric aliphatic or cycloaliphatic alcohols--if appropriate in mixtures with other inert solvents which are miscible with the carboxylic acid/alcohol mixture. Preferred solvents comprise acetic acid/methanol and acetic acid/ethanol mixtures.The reaction products are final products and intermediates products in various specialized fields such as, for example, the plant protection sector and the polymers sector.

Abstract: The invention relates to a process for the preparation of vinylphosphonic dichloride through elimination of hydrogen chloride from 2-chloroethanephosphonic dichloride in the presence of catalysts. The catalysts used are tertiary phosphines, quaternary ammonium or phosphonium salts or alkali metal or alkaline-earth metal halides. When triphenyl phosphine is used as the catalyst, the reaction is carried out under reduced pressure at a temperature of 130.degree. to 166.degree. C. and the vinylphosphonic dichloride produced is simultaneously removed by distillation under reduced pressure. When the other catalysts are used, the process can be carried out at atmospheric pressure or reduced pressure and at temperatures of about 130.degree. to 220.degree. C. and the vinylphosphonic dichloride produced can be removed by distillation simultaneously with or subsequent to the reaction.

Abstract: The invention relates to a process for the preparation of vinylphosphonic dichloride, in which a 2-chloroethanephosphonate of the formula ##STR1## or a mixture of the two esters, is reacted with thionyl chloride at a temperature of 60.degree. to 160.degree. C. in the presence of a catalyst which contains tertiary phosphines, quaternary ammonium or phosphonium salts or alkali metal or alkaline-earth metal halides.During this reaction, any thionyl chloride which may be present is removed by distillation subsequent to this reaction, the mixture remaining is heated to 140.degree. to 200.degree. C., and the vinylphosphonic dichloride produced during this is removed by distillation.

Abstract: The invention relates to a process for the preparation of 2-chloroethanephosphonic dichloride through reaction of a 2-chloroethanephosphonate of the formula ##STR1## or a mixture of the two esters, with thionyl chloride at a temperature of 60.degree. to 160.degree. C. In this reaction, tertiary phosphines, quaternary ammonium or phosphonium salts or alkali metal or alkaline-earth metal halides are employed as catalysts. The thionyl chloride is introduced into the initially introduced ester.

Abstract: Tertiary phosphine oxides are prepared by the oxidation of tertiary phosphine sulfides with H.sub.2 O.sub.2 in a solvent composed of at least about 20% by weight, preferably at least about 50% by weight, of optionally halogenated, lower aliphatic carboxylic acids and/or their anhydrides; it is particularly preferred if the solvent is composed only of acetic acid.The reaction products are end products and intermediates in a variety of areas such as, for example, the sectors of plant protection and polymers.

Abstract: Tertiary aromatic phosphine sulfides of the formula ##STR1## wherein X=F, Cl or Br, are prepared by means of a Friedel-Crafts reaction of(a) PCl.sub.3 with benzene and--after the addition of sulfur--also with fluorobenzene, chlorobenzene or bromobenzene, or(b) PSCl.sub.3 with fluorobenzene, chlorobenzene or bromobenzene and subsequently also with benzene; Friedel-Crafts catalysts are Al halides, especially AlCl.sub.3.The products are used as end products and intermediates in a variety of areas, such as, for example, the sectors of plant protection and polymers.

Abstract: 2-(Meth)acrylamido-2-methylpropanephosphonic acid is prepared by reaction of 2-methylprop-1-ene-1-phosphonic acid or 2-methylpro-2-ene-1-phosphonic acid with (meth)acrylonitrile in the presence of an equimolar amount of a strong acid. The compounds are suitable as such or in the form of their salts as comonomer for the manufacture of copolymers, which are used inter alia as dyeing auxiliaries and as scale inhibitors.