5-Chloro-2-Methylaniline
Fast Red KB Base — the chlorinated o-toluidine diazo component supplied by Chelora Chemicals for azoic dyeing and azo pigment manufacture, exported from Indonesia with full batch documentation on every shipment.
What 5-Chloro-2-Methylaniline is, and why buyers source it
A working overview of the compound's chemistry, its place in the aniline-derivative family, and the grades Chelora Chemicals keeps in regular supply.
5-Chloro-2-Methylaniline carries a methyl group beside the amine and a chlorine across the ring from it. In the colour trade it is better known by its azoic name, Fast Red KB Base, registered as C.I. Azoic Diazo Component 32 — the form in which it is diazotized and coupled on the fibre to develop fast red shades. It has a long parallel history in histochemistry, where the Fast Red KB salt is used with naphthol AS-phosphate substrates to visualise phosphatase activity.
Its melting point of 22–23 °C sits almost exactly at room temperature, which is the single most practical thing to know about handling it. The same lot can arrive as a white to yellow or orange powder or lump in a cool store and as a clear yellow to light-brown liquid in a warm one, and both are the material you ordered. It is poorly soluble in water at under 1 g/L and dissolves readily in common organic solvents and dilute acid.
Where it fits in the synthesis chain
The dominant use is azoic or ingrain dyeing: the amine is diazotized and the resulting salt is coupled with a naphthol coupling component already fixed on the fibre, developing an insoluble azo pigment inside the fibre itself and giving the wash fastness that azoic reds are valued for. It is applied on cotton, silk, nylon and other cellulosics, and the same chemistry serves azo pigment manufacture. It is also used as a building block for pharmaceutically active compounds.
Grades we supply
Chelora Chemicals offers 5-Chloro-2-Methylaniline in technical grade (98%) and high-purity grade (99%+), both with a batch-wise certificate of analysis. For dyehouse buyers the specification lines that matter are isomer purity and colour, since both carry directly into the shade developed on the fibre. Trial quantities can be arranged before a volume commitment.
How 5-Chloro-2-Methylaniline is made
An overview of the production route for orientation purposes. Our manufacturing partners' own process parameters and in-process controls are proprietary and are not disclosed beyond what is needed to interpret the certificate of analysis.
5-Chloro-2-Methylaniline is made by reducing 2-nitro-4-chlorotoluene, by catalytic hydrogenation or by the iron and hydrochloric acid Béchamp route. The nitro precursor comes from the nitration of 4-chlorotoluene, and the isomer distribution of that nitration — followed by separation — sets the substitution pattern of the finished amine.
Because the related chlorotoluidine isomers have close boiling points and similar solubilities, the separation is the demanding part of the process rather than the reduction. Material is produced in relatively small quantities compared with the bulk chloroanilines, which is reflected in both availability and price.
After reduction the amine is washed and distilled or recrystallised. The low melting point shapes the final handling: product is cut, cooled and packed in a form appropriate to the destination climate, and flaking is not always practical.
The name to get right: KB, not TR
This product is Fast Red KB Base. It is not Fast Red TR Base — that name belongs to 4-chloro-2-methylaniline, CAS 95-69-2, a different compound that carries an IARC Group 2A carcinogen classification and a harmonised EU Carc. 1B entry. The two are frequently confused in catalogues and purchase orders because the names and the structures are so close. Specify CAS 95-79-4 on your order and verify it on the certificate of analysis at goods-in.
Industries and processes that use it
5-Chloro-2-Methylaniline is consumed almost entirely as a synthesis intermediate. The four fields below account for most of the demand we see through our export desk.
Azoic Dyeing
As Fast Red KB Base, C.I. Azoic Diazo Component 32, diazotized and coupled on the fibre with naphthol components to develop fast red shades on cotton, silk, nylon and cellulosics.
Azo Pigments
A diazo component for azo pigment manufacture, where the methyl and chlorine substituents together set shade and fastness.
Histochemistry
The Fast Red KB salt is used with naphthol AS-phosphate substrates to visualise phosphatase activity in tissue staining.
Fine Chemical Synthesis
A building block for pharmaceutically active and other biologically active compounds.
How the molecule is typically carried forward
The amine is the reactive handle and the diazonium salt is the working form. In azoic dyeing both steps happen around the fibre rather than in a vessel, which is what distinguishes this chemistry from conventional dye application.
Diazotization
Nitrous acid generated in situ from sodium nitrite and mineral acid below 5 °C gives the diazonium salt. In the trade this is supplied or prepared as the stabilised Fast Red KB salt.
Naphtholation of the Fibre
Separately, the textile is impregnated with an alkaline solution of a naphthol coupling component, which is absorbed and held by the fibre.
Coupling on the Fibre
The naphtholated fibre is passed into the diazonium solution and the azo pigment forms inside the fibre, insoluble and mechanically trapped — the origin of azoic dyeing's wash fastness.
Acylation
Reaction with an acid chloride or anhydride gives the anilide, used in building further intermediates.
5-Chloro-2-Methylaniline against its near relatives
The chlorinated o-toluidines are a family in which names mislead and CAS numbers decide. The table below sets out the ones that matter commercially, including one we do not supply and which is routinely confused with this product.
| Product | CAS Number | Typically Used In | Notes |
|---|---|---|---|
| 5-Chloro-2-Methylaniline | 95-79-4 | Fast Red KB Base azoic dyeing, azo pigments | The product on this page. IARC Group 3 — see the hazard section. |
| 3-Chloro-2-Methylaniline | 87-60-5 | Azoic and naphthol dyeing, specialty synthesis | Also supplied — see its product page. No IARC evaluation. |
| 4-Chloro-2-Methylaniline | 95-69-2 | Historically Fast Red TR Base | Not supplied. IARC Group 2A and EU Carc. 1B. Listed here because it is the compound most often confused with this one. |
| Ortho Chloroaniline | 95-51-2 | Sulfonylurea herbicides, azo dyes, MOCA | The unmethylated relative — see its product page. |
Exact physical constants and purity specifications are confirmed per batch on the certificate of analysis — treat the notes above as a sourcing guide rather than a specification sheet.
Safety classification at a glance
Based on GHS classification as commonly listed for this substance. This is a summary for orientation only — always work from the current safety data sheet supplied with your specific batch.
Harmful if swallowed.
Causes skin irritation.
Causes serious eye irritation.
May cause respiratory irritation.
Causes damage to organs.
Causes damage to organs through prolonged or repeated exposure.
Danger — GHS07 harmful and GHS08 health hazard pictograms apply.
This substance has no harmonised entry in Annex VI to CLP, so classification is supplier self-classification under CLP Article 4(3), and suppliers differ: some classify only irritation endpoints with the signal word Warning, while others add the organ-toxicity endpoints shown above with the signal word Danger. The codes here are a conservative envelope; work from the safety data sheet issued with your batch. On carcinogenicity the position deserves stating fully rather than in summary: IARC evaluated this substance in Volume 77 and placed it in Group 3, not classifiable as to its carcinogenicity to humans — but the US National Toxicology Program bioassay TR-187 found it carcinogenic in B6C3F1 mice, with no conclusive evidence in rats, and the Australian regulator has recommended a Category 2 carcinogen classification on weight of evidence. It is also banned in cosmetic products under EU Regulation 1223/2009. Quoting the IARC group alone would be accurate but incomplete.
Keeping it on spec between delivery and use
General storage guidance for this grade. Site-specific storage rules, segregation requirements and re-test intervals should follow your own EHS procedures and the MSDS issued with your batch.
Store in a cool, dry, well-ventilated area, protected from light, in tightly closed original containers away from oxidizers and strong acids. Because the melting point is 22–23 °C, physical form will change with ambient temperature and in transit; this is expected and does not affect the specification. If a drum is partly melted, homogenise it before drawing a sample or the assay will not be representative. Keep containers closed to limit moisture pickup and colour drift, since feed colour carries directly into the developed shade.
How it ships from Indonesia
Standard packing and export terms for this product. Confirm exact figures against your order — they vary slightly by destination and quantity.
What travels with every batch
Specification is agreed before the purchase order, not discovered on arrival. Every shipment of 5-Chloro-2-Methylaniline leaves with a documented, checkable paper trail.
Certificate of Analysis
Batch-wise assay (by GC), isomer purity, melting point range and moisture, issued against the agreed specification so your QC team can check it, not just file it.
Safety Data Sheet
GHS-format SDS in English covering hazard classification, handling, storage, first-aid and spill response for the exact grade shipped.
Technical Data Sheet
Reference physical and chemical properties, recommended storage and typical applications, for internal circulation to your process or R&D teams.
Certificate of Origin
Confirms Indonesian origin for customs clearance and any preferential-duty claim at your destination port.
Dangerous Goods Declaration
UN packing group, classification and shipper's declaration prepared ahead of loading so documentation never holds up customs.
Third-Party Inspection
Independent pre-shipment inspection and re-sampling can be arranged on request, at your cost, for buyers who require it as a matter of policy.
Frequently asked questions
What buyers most often ask our sales desk about this grade.
01What is 5-Chloro-2-Methylaniline used for?+
02What is the CAS number of 5-Chloro-2-Methylaniline?+
03What purity grades does Chelora Chemicals supply?+
04Is 5-Chloro-2-Methylaniline hazardous?+
05Is this the same as Fast Red TR Base?+
06What is the carcinogenicity status of this grade?+
07Will it arrive solid or liquid?+
08What packing options are available?+
09How long does delivery take?+
10Can I get a sample before placing a bulk order?+
11How is 5-Chloro-2-Methylaniline manufactured?+
12What is the shelf life, and how should it be stored?+
Need 5-Chloro-2-Methylaniline on spec, on time?
Send us your required purity, quantity, packing preference and destination port. Our desk quotes most enquiries within one working day.