O-TDA is a mixture of ortho-isomer toluenediamines, used as a reactive amine initiator in rigid polyol production and as an intermediate in dyes and specialty chemicals. Ambizent supplies O-TDA worldwide, with a Certificate of Analysis on every shipment.
Ortho-toluenediamine (O-TDA) is a specialty aromatic diamine used mainly as a reactive initiator in rigid polyol production, and as an intermediate in dyes and other specialty chemicals. It is often confused with the toluenediamine used to manufacture TDI — a genuine and important distinction we set out clearly below, because getting it wrong matters to a formulator.
What O-TDA actually is
Toluenediamine (TDA) exists as several positional isomers. The two isomers used to manufacture toluene diisocyanate (TDI) are 2,4-diaminotoluene and 2,6-diaminotoluene. During TDA manufacture, a separate stream of ortho-isomer toluenediamines is also produced — predominantly 3,4-diaminotoluene and 2,3-diaminotoluene — and this technical mixture is what the industry sells as O-TDA (also written OTD or OTDA). It is a genuinely different product from 2,4-/2,6-TDA, even though the names look alike, and it is not suitable for TDI manufacture. We describe it this way — as a defined isomer mixture rather than a single compound — because commercial listings for O-TDA vary in how precisely they identify it, and a technical buyer deserves an accurate description before ordering.
Applications
Amine-based (Mannich) polyol production — an initiator/co-reactant for rigid, high-reactivity polyols.
Dye & pigment intermediates — a precursor for certain dyestuffs.
Epoxy curing & specialty resins — reactive amine building block.
Corrosion-inhibitor & specialty chemical synthesis — general aromatic diamine intermediate use.
The largest application for O-TDA is as an initiator in amine-based (Mannich) polyols — reactive polyols used in rigid polyurethane foam where fast reactivity and short demould times matter, such as in appliance and panel production. It also serves as an intermediate in dye and pigment synthesis and in epoxy and specialty-resin curing systems.
Typical properties
Property
Typical value
Chemical description
Mixture of ortho-isomer toluenediamines (predominantly 3,4- and 2,3-diaminotoluene)
Molecular formula
C7H10N2 (per isomer)
Appearance
Light grey to purple solid at ambient temperature; darkens on exposure to air
Handling temperature
Typically unloaded molten, around 88–93 °C
Packaging
Drums (molten or cast solid), matched to route and volume
Values are typical and for guidance only; exact isomer ratio and purity are confirmed on the batch Certificate of Analysis provided with every shipment. Always consult the current Safety Data Sheet before handling.
Why source O-TDA from Ambizent
Correct identity, verified — we describe O-TDA as the isomer mixture it actually is, not a mislabelled TDI precursor.
Certificate of Analysis on every shipment.
Worldwide supply from our UAE hub — the Middle East, Africa, South Asia and beyond.
Documentation handled — SDS, dangerous-goods paperwork, certificates of origin and Incoterms end to end.
O-TDA (ortho-toluenediamine, also written OTD or OTDA) is a technical-grade mixture of the ortho-isomer toluenediamines — predominantly 3,4-diaminotoluene and 2,3-diaminotoluene. It is generated as a co-product when toluenediamine is manufactured, and is repurposed as a reactive amine building block rather than discarded.
Is O-TDA the same as the TDA used to make TDI?
No, and this is an important distinction. Toluene diisocyanate (TDI) is made from 2,4- and 2,6-diaminotoluene. O-TDA is a different set of isomers (mainly 3,4- and 2,3-diaminotoluene) that are not suited to TDI production. The two are related co-products of the same manufacturing process but are used in entirely different applications — buyers should confirm which isomer set they need before ordering.
What is O-TDA used for?
O-TDA's main industrial use is as a reactive amine initiator in the production of amine-based (Mannich-type) polyols used in rigid polyurethane foam, where it contributes to high reactivity and fast demould times. It is also used as an intermediate in dye and pigment manufacture, epoxy curing systems and other specialty chemical synthesis.
Is O-TDA hazardous?
Toluenediamine isomers, including those in O-TDA, are classified as hazardous — they carry health warnings for skin and eye contact and require careful handling, and some isomers have flagged toxicological concerns in regulatory reviews. Always follow the Safety Data Sheet, use appropriate personal protective equipment, and handle in a well-ventilated area.
What packaging is O-TDA supplied in?
O-TDA is typically supplied in drums, sometimes as a molten or solidified cast product depending on the grade and route, matched to your volume and handling capability. Ambizent manages packaging, dangerous-goods documentation and Incoterms end to end.
Let's Work Together
Need Ortho-Toluenediamine (O-TDA)?
Tell us your required grade, quantity and destination port — we'll quote from a reliable supply base with a Certificate of Analysis on every shipment.