Abstract: A synthesis for an azo intermediate, 5,5?-azobis(4-chloropyrimidine) is disclosed. 5,5?-azobis(4-chloropyrimidine) is a relatively stable azo compound in that decomposition does not occur until about 194° C. 5,5?-azobis(4-chloropyrimidine) is a product of oxidative dimerization of 5-amino-4-pyrimidine, which a water soluble compound. The azo intermediate is formed in an aqueous solution, but the azo intermediate is substantially insoluble in water; and as it forms it separates producing a reaction mixture that is a slurry. The azo intermediate is isolated by filtration. The azo intermediate is marginally soluble in acetone. The yield is at least 18%, and the oxidizing agent (bleach) is inexpensive, reaction conditions do not require extreme heat or cold, which taken together make the azo intermediate suitable for scaling up.

Abstract: Thermally stable functionalized organosilicon compounds containing at least one activated azo group, of formula (I): [(G0)3SiO1/2]m[(G0)2SiO2/2]n[G0SiO3/2]o[SiO4/2]p[(G2)a(G1)a?(Z-CO—HN?NH—CO-A)SiO(3-a-a?)/2] are synthesized from at least one hydrazino precursor (II) (—HN—NH—) of the compound (I), oxidizing the precursor (II) into an azo group for the compound (I), employing an oxidizing system including at least one oxidizing agent (Ox) and at least one base (B), such oxidizing being carried out in a two-phase aqueous/organic medium and such that the pH of the aqueous phase ranges from 3 to 11.

Abstract: The present invention relates to a process for the preparation of aromatic azo-compounds, in particular 3,3′-azo-bis(6-hydroxybenzoic acid) (olsalazine) and its salts and derivatives.

Abstract: An azodinitrile composition comprising a mixture of at least six different azodinitriles of formula I ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, and R.sub.4 are each independently acyclic aliphatic hydrocarbon radicals of 1-9 carbon atoms, said mixture having a freezing point of a maximum of 25.degree. C. and a process for its preparation are disclosed.

Abstract: The invention discloses a process for the preparation of azo dyes using an aminodiphenylamine as diazo component. The process comprises reacting the amine, an alkali metal nitrite and a mineral acid continuously in the temperature range from 35.degree. to 65.degree. C. to give the diazo compound, using a 3 to 15% excess of alkali metal nitrite, and thereafter coupling the diazo compound to a coupling component. Azo dyes of superior quality constancy and in high yield are obtained by the novel process.

Abstract: Compounds of the formula ##STR1## in which X represents hydrogen, --NO.sub.2 or --NH.sub.2 and Y represents --CH.sub.3, --COOH, --CONH.sub.2, --NH.sub.2 or --N.dbd.N--Z, in which the group --Z is ##STR2## with the proviso that if Y represents the group --N.dbd.N--Z, X is only --NO.sub.2, and if Y represents the group --CH.sub.3, X is only hydrogen, are described. A compound of the formula ##STR3## the preparation of which in a multi-stage process, in which the compounds of the general formula (I) are also obtained, is described, is preferred.The resulting 3,4'-diamino compound is suitable for the preparation of polycondensates and shaped articles, films and fibers of high heat resistance.

Abstract: 2-Hydrazono-4,6-dinitrobenzthiazolones of the formula ##STR1## in which X.sub.1 represents hydrogen, C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -hydroxyalkyl, C.sub.1 -C.sub.4 -sulphoalkyl or C.sub.1 -C.sub.4 -sulphatoalkyl, andX.sub.2 represents hydrogen or --SO.sub.2 X.sub.3, whereX.sub.3 may represent hydrogen, C.sub.1 -C.sub.8 -alkyl or optionally substituted aryl andX.sub.1 also represents a double bond between the cyclic nitrogen atom and the carbon atom 2 according to the formula II below: ##STR2## where X.sub.2 has the meaning specified under the above formula. These hydrazones may be employed in the preparation of azo dyestuffs and as color formers for detecting of biological substances, and in the determination of H.sub.2 O.sub.2.

Abstract: The invention concerns azo compounds of formula ##STR1## or a salt thereof, in which formula R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, and R.sup.6 are each independently hydrogen or lower alkyl, R.sup.7 and R.sup.8 are each independently alkyl of 1 to 7 carbon atom or cycloalkyl of 5 to 7 carbon atoms optionally substituted by lower alkyl which possess anti-inflammatory activity.

Abstract: A universally usable process for preparing azo dyestuffs by oxidative coupling consists in carrying out the oxidation in the presence of redox mediators with a standard potential of 0.2-1.5 volts and, if appropriate, an additional oxidizing agent with a standard potential of 0.25-2.5 volts, wherein the sum of the oxidation equivalents should be at least 4. The preferred redox mediator is iodine. The process is particularly suitable for the preparation of heteroaromatic azo dyestuffs using an aniline coupling component.

Abstract: A process for the preparation of 2,2'-azobis(2-methylbutanenitrile) in high yield, good quality and filtering and drying characteristics by reacting 2-amino-2-methylbutanenitrile with a metal hypochorite in the presence of water and a mixture of surface active compounds at a temperature of about -10.degree. C. to about 30.degree. C. and recovering the 2,2'-azobis(2-methylbutanenitrile) from the reaction mixture.