TDI / MDI high purification

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Fives Proabd Chemtec Products TDI caseStudy Isocyanate-FIVES Fives in Chemtec
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TDI / MDI are important compounds for the production of several grades of polyurethane materials.

TDI (Toluene Diisocyanate) is, after MDI (Methylene Diphenyl diisocyanate), the second largest isocyanate produced on the market for the production of polyurethane plastics. These polymers are obtained by reaction of the isocyanate group with the alcohol group of another product. They find applications in a variety of field such as fibers, foam, adhesives or elastomers.

Polyurethane materials performance and properties are obtained by means of the right selection of TDI grade mixture.

The production process of TDI generates a 80:20 crude mixture containing 80% of 2,4 TDI (CAS: 584-84-9) and 20% of 2,6 TDI (CAS: 91-08-7). This crude TDI is directly marketable as T-80. Some specific applications require the use of 65:35 mixture or 100:0 pure 2,4 TDI, respectively commonly known as T-65 and T-100 on the market.

TDI is a thermo sensible product. It is freezing below 15°C and may form dimers when heated above circa 43°C which will negatively impact the color of final product.

It is also a very reactive compound with uncontrollable exothermic polymerization when in contact with bases, active hydrogen containing compounds or water.

TDI vapors are toxic and have a pungent odor.

To obtain the ultimately purified 2,4 isomer, known as T-100 grade, from a T-80 grade TDI mix, purification operation is performed in a multistage purification Proabd® crystallizer. T-65 commercial grade is obtained as a side product.

Proabd® MSC process does not generate any waste stream. All the feed is recovered as marketable products. It is a fully automated process based on proprietary predictive control system.

Fives Proabd Chemtec Diagram TDI Purification-FIVES Fives in Chemtec

Proabd® MSC is a technique of choice for the purification of monomers subject to self polymerization, especially when thermal stability is required (typical products are MDI, TDI, acrylics, caprolactam, …). The process is designed on the basis of recommandations and best practices for TDI handling and storage.

Fives can manage the project from feasibility studies to design, engineering and construction.

  • Very low specific energy consumption
  • Low operating and maintenance costs
  • Optimized performances
  • Environmentally friendly and safe thanks to collection networks for vent gas and draining oils
  • Process designed on the basis of recommendations and best practices for TDI handling and storage
  • Very high recovery yield
  • High 2,4 TDI isomer ratio
  • Very high plant availability factor
  • Low electrical and steam consumption


The Proabd® MSC process for the purification of TDI / MDI, acquired from BEFS Prokem, is a leading technology for increasing the added value of products port-folio by adding T-100 and T-65 grades to your existing T-80.

  • Rhône Poulenc - France (8,000 tpy)
  • KPX (formerly Korea Fine Chemical Co.) - Korea (1,700 tpy - 1993)
  • Confidential customers - South Korea (4,400 tpy - 2011) - China (10,500 tpy - 2013)

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