Bayer Aktiengesellschaft

Gunther Cramm

Friedhelm Muller

Wolfgang Lehmann

Wilfried Lobach

Janos Muszik

Guido Steffan

Gunter Kolb

Knut Hammerstrom

Eckart Kranz

Hans Lindel

Wolf-Dieter Schroer

Otto Benn

Volker Kass

Gunter Hellrung

Karl H Blocher

4,6-Dichloropyrimidines are obtained by the reaction of 4,6-dihydroxypyrimidines with excess phosphoryl chloride in a particularly advantageous manner when no base is added, during and/or after the reaction 0.75 to 1.5 mol of phosphorus trichloride and 0.7 to 1.3 mol of chlorine are added per equivalent of exchanged hydroxyl groups so that an excess of phosphorus trichloride with respect to chlorine is always present, and finally phosphorus trichloride and phosphoryl chloride are separated off. This process can be carried out in a particularly simple manner and also continuously.

Process for the preparation of 4,6-dichloropyrimidines

2-Chloropyridine derivatives of the formula (I) ##STR1## in which R represents hydrogen, C.sub.1 -C.sub.4 -alkyl or halogen and

Process for the preparation of 2-chloropyridines

The present invention relates to agents for increasing the retention of fibres, fillers and pigments and for accelerating drainage in papermaking, and as flocculating agents in the working up of effluents from papermaking by filtration, sedimentation and flotation. They are characterized in that they contain, as active components, one or more nitrogen-containing condensation products which can be obtained by reacting (A) aliphatic polyol-ether-amines which are free from halogen groups, contain cohesive polyether segments and carry no amino groups within these segments, with (B) compounds which are polyfunctional towards amino groups, optionally in the presence of (C) polyaminopolyamides and/or (D) polyalkylenepolyamines, component (B) being employed in an amount such that water-soluble polycondensates which have a viscosity of 100 to 1,000 mPa.s at 25.degree. C. in 25% strength aqueous solution are formed.

Paper auxiliary from condensation product of aliphatic

Non-crosslinking, water-soluble polyamines which can be obtained by reacting

Polyamines containing urea groups prepared from lactam or

Non-crosslinking, water-soluble polyamines which can be obtained by reacting (A) basic polyureas which have been prepared by condensation of ureas with polyamines containing at least three amino groups, of which at least one is a tertiary amino group, or with mixtures of these polyamines with aliphatic, araliphatic, cycloaliphatic or heterocyclic polyamines containing two primary or two secondary amino groups or one primary or one secondary amino group, and optionally with .omega.-aminocarboxylic acids containing at least three carbon atoms, or lactams thereof, (B) polyalkylenepolyamines of the general formula ##STR1## in which R denotes H or CH.sub.3, the indices y are in each case identical or different and denote the number 0 or 1 and

Polyamines containing urea groups

In the production of thiocarbohydrazide by reacting hydrazine hydrate with carbon disulphide in the presence of water to form in a first stage hydrazinium dithiocarbazinate, subsequently thermally decomposing the hydrazinium dithiocarbazinate in a second stage to form thiocarbohydrazide, and recovering the thiocarbohydrazide from the reaction medium, the improvement which comprises effecting the entire reaction in the mother liquor of a preceding batch, carrying out the first reaction stage at a temperature between about 25.degree. C. and 45.degree. C., with injection of carbon disulphide below the surface of the reaction mixture; carrying out the second stage at about 62.degree. to 65.degree. C. without prior isolation of the intermediate product; filtering off the thiocarbohydrazide formed after cooling, separating the amount of mother liquor in excess of that required for the next batch, and feeding the balance of the mother liquor to the next batch. The excess mother liquor not required for the next batch is heated to about 70.degree. to 75.degree. C., and after separating off the thiocarbohydrazide, the remaining mother liquor is subjected to combustion.

Production of thiocarbohydrazide on a commercial scale

Water-soluble amines which are not self-crosslinking and are obtainable by reacting (A) one or more water-soluble or water-dispersable amines containing amide groups, prepared by condensation of (a) 1 mol of dicarboxylic acid or functional derivatives thereof, (b) 0 to 30 mols of aminocarboxylic acids containing at least three C atoms, or lactams thereof, and (c) 1.4 to 30 mols of polyalkylenepolyamines of the general formula ##STR1## in which R denotes H or CH.sub.3,

Polyamines containing amide groups

Water-soluble polyamines which are obtainable by reacting

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Cologne, Germany

Gunther Cramm