Dye Intermediate 2-Chlorobenzaldehyde CAS 89-98-5 Azo Pigment Synthesis Grade Liquid

Colour chemistry is unforgiving about impurities: a fraction of a percent of a coloured by product in the aldehyde becomes a visible shade difference in the pigment or dye, and it cannot be corrected later in the process. 2-Chlorobenzaldehyde (CAS 89-98-5) is used to build ortho chloro substituted intermediates for azo pigments, methine dyes and optical brightener routes, where the aldehyde is condensed with an active methylene or an aromatic amine.

For that reason this dye intermediate grade is specified on colour of the liquid, on the tar content after a standardised acid test, and on the chlorobenzoic acid level that otherwise reacts with the coupling component to give a dull, off shade product. Distilled material packed under nitrogen keeps the visual quality stable through a production campaign, so a dye house does not see the batch to batch shade drift that technical grade aldehyde produces.

• Assay 99.0% minimum by GC: complete condensation with the coupling component and predictable colour yield
• Low tar content in the acid test: no coloured by products that would shift the shade of the finished pigment
• 2-Chlorobenzoic acid 0.5% maximum: limits the dulling impurity that reacts with amines during coupling
• Colour 50 APHA, controlled: consistent starting colour so the shade of the batch is reproducible
• Distilled, nitrogen packed: stable through a campaign without darkening in the drum
• Documented batch data: GC chromatogram and colour data supplied so shade issues can be traced quickly

Used in the synthesis of ortho chloro substituted azo pigments, methine and polymethine dyes, optical brightening agents, and in the preparation of dye intermediates where a defined isomeric composition is required for shade reproducibility.

The condensation is normally run in an alcohol or acetic acid medium at 60 to 85 degrees C with acid catalysis; adding the aldehyde slowly to the coupling component keeps the local concentration low and minimises self condensation. Our technical note includes a standardised shade comparison method and storage recommendations for drums in use.

Packed in 25 kg plastic drums and 250 kg iron drums with phenolic epoxy lining, nitrogen blanketed and sealed. Labels carry lot number, assay, colour, production date and hazard information in English.

Store below 30 degrees C away from light, oxidisers and bases; colour drift is the first sign of oxidation, so drums should be used within six months of opening. Deliveries leave Shanghai within 7 to 15 working days with COA and safety data sheet.

A Certificate of Analysis accompanies each lot with assay, free acid, water, colour, tar content by the acid test and the GC chromatogram. A 200 g retention sample is held for 18 months for shade dispute resolution.

We supply the GHS safety data sheet, a technical data sheet describing the acid test method, and a colour comparison protocol. Custom distillation cuts with tighter colour limits can be produced for pigment customers with volume programmes.