Toluenediamine (TDA)

Most commercial nitro group hydrogenation processes are related to fine chemistry and pharmaceutical chemistry, but in terms of product quantity, the most important process is the hydrogenation of dinitrotoluene (DNT) to toluenediamine (TDA). TDA is an intermediate in the production of polyurethanes (PUs). It is converted with phosgene to toluenediisocyanate (TDI), which is mainly used, together with polyether polyols, for the production of flexible PU foams for furnishings, packaging foam, mattresses and car seats. Together, these products account for some 90% of its usage.

Evonik offers the following catalyst systems for the hydrogenation of DNT:

• Activated Base Metal Catalysts (Nickel)
• Precious Metal Powder Catalysts supported on activated carbon
• Precious Metal Powder Catalysts supported on carbon black

You can find detailed information on catalyst types and reaction conditions in the Catalyst Guide

Our >>FF^® TDA Technology – fast filtering catalysts based on carbon black

Carbon black based catalysts are excellent catalysts in the hydrogenation of DNT to TDA. However, the filtration of the catalyst may lead to long filtration times because of the morphology of the catalyst particles. Evonik developed the >>FF^® TDA Technology which provides TDA catalysts which show the same or even higher activity as carbon black based catalyst, but can be as easily filtered as activated carbon based catalyst. This is a unique combination of benefits which is unsurpassed in the market.

For more details about the >>FF^® TDA Technology please contact your Evonik sales manager.

Services for TDA customers

Apart from offering tailor-made TDA catalysts, Evonik provides technical support and in-house testing of catalysts. Through our collaborations with engineering companies, we keep in touch with the latest technology. We have an elaborate testing system for TDA catalysts that starts with a high throughput pre-screening, includes batch tests and ends with testing under customer-identical conditions in a semi-continuous mini plant.