Ortho Phenylenediamine

Ortho Phenylenediamine's adjacent (1,2) amino groups allow it to condense with a carboxylic acid, aldehyde, or similar carbonyl partner to close a five-membered benzimidazole ring -- the single most important reaction this compound undergoes, and the basis of essentially all of its documented commercial applications. We want to state its mutagenicity finding precisely rather than loosely: the EU-harmonised H341 ("suspected of causing genetic defects") classification is based on positive results in somatic-cell genotoxicity assays specifically, not in heritable germline mutagenicity tests, where results were negative. This is a narrower, more precise finding than a flat "mutagen" label would suggest, and we state it at that precision.

We also want to correct a specific, easy-to-make assumption about this compound's cancer-classification status: unlike several chlorinated phenylenediamine derivatives that IARC has separately reviewed under a commonly-cited document title, we could not confirm an IARC Group evaluation specifically for this unsubstituted parent compound in the sources we checked, and we do not state one. Commercially, it is documented as an intermediate in azo-dye and sulfur-dye synthesis, as a precursor to diaminobenzidine-type histochemical and analytical reagents, and -- in more recent literature -- as a building-block in emerging benzimidazole-based battery and fuel-cell electrode materials.

Where it fits in the synthesis chain

We supply Ortho Phenylenediamine itself as a dye, reagent, and fine-chemical intermediate. We do not manufacture or supply finished dyes, analytical kits, or battery/fuel-cell materials made using it.

Grades we supply

99%+ technical and analytical grades are both offered.

Ortho Phenylenediamine is made industrially by reduction of ortho-nitroaniline or 2-nitroaniline-type precursors, or by reduction of ortho-dinitrobenzene, converting the nitro group(s) to amino groups.

The reduction step uses catalytic hydrogenation under controlled conditions to ensure complete conversion without over-reduction side reactions.

The crude product is purified by distillation or crystallisation and packed promptly under conditions that limit air and light exposure, since it darkens readily and oxidises on standing.

A precise mutagenicity finding, and a cancer-classification claim we don't make

Two things deserve precision here rather than a simplified summary. First, the H341 mutagenicity classification rests specifically on positive somatic-cell genotoxicity results, with negative results in heritable germline mutagenicity testing -- a narrower finding than "mutagen" alone conveys, and we state it at that precision rather than collapse the distinction. Second, a commonly-cited IARC document title referencing phenylenediamine compounds actually covers certain chlorinated derivatives, not this unsubstituted parent compound -- we checked specifically and could not confirm a separate IARC Group evaluation for this exact substance, so we do not state one.