Ciba-geigy Corporation

Werner Surber

Abul Iqbal

Michael Reisinger

Bilge Gulec

Klaus Ruf

Christian Stern

The present invention relates to the preparation of bisazo pigments by reaction (a) of 2 mol of an azocarbonyl chloride of the formula ##STR1## with 1 mol of a diamine of the formula ##STR2## by reaction (b) of one mole of a bis(azocarbonyl chloride) of the formula ##STR3## with 2 mol of an amine of the formula ##STR4## which comprises carrying out the reactions (a) or (b) in the presence of 1,2,3-trimethylbenzene or anisole as the solvent.

Process for the preparation of bisazo pigments in halogen-free solvents

Process for the preparation of 1,4-diketopyrrolo[3,4-c]pyrroles of the formula I ##STR1## in which R.sub.1 and R.sub.2 independently of one another are phenyl, biphenyl or naphthyl radicals or aromatic O-heterocyclic, S-heterocyclic or N-heterocyclic radicals, by reacting 1 mole of a dicyclohexyl succinate, dialkyl succinate, monoalkylmonophenyl or diphenyl succinate, alkyl in the succinic acid ester radical being C.sub.1 -C.sub.18 alkyl and phenyl being phenyl which is unsubstituted or substituted by one or two halogen atoms or one or two C.sub.1 -C.sub.6 alkyl or C.sub.1 -C.sub.6 alkoxy groups, with 2 moles of a nitrile of the formula II or III or with 1 mole of a nitrile of the formula II and 1 mole of a nitrile of the formula III ##STR2## in which R.sub.1 and R.sub.2 are as defined above, in an inert organic solvent, in the presence of an alkali metal or an alkali metal alcoholate, as a strong base, and at an elevated temperature to give an alkali metal salt of the formula IV ##STR3## in which M is an alkali metal, and subsequently liberating a compound of the formula I by protolysis of a compound of the above formula IV, which comprises treating, in stages, a compound of the above formula IV in at least two portions, as a protolysing agent, with water, with an inorganic and/or organic acid, with a mixture of water and an organic solvent, or with a mixture of an inorganic or organic acid and water and/or at least one organic solvent, and reacting the mixture at a temperature from 20.degree. to 150.degree. C. after the addition of each of the portions.

Process for the preparation of pyrrolo[3,4-c]pyrroles

A process for the preparation of alkali metal tertiary alcoholates by reacting an alkali metal with a tertiary alcohol, which process comprises adding the hot alcohol, with stirring, to the melted alkali metal. Said process has the advantage that no inert solvents are required.

Growing community of inventors

Oberwil, Switzerland

Werner Surber