Trichloroethylene as a solvent in the production of caprolactam



One company using Trichloroethylene in the extraction process of caprolactam has submitted an Application for Authorisation to the European Chemicals Agency ECHA to allow continued use. This request is hence a call for alternative providers to submit to ECHA information about their possible technology that could replace Trichloroethylene in this process. All kinds of alternatives are highly wanted; Alternative solvents, process changes and alternative technologies which can lead to the substitution of Trichloroethylene in the production of caprolactam.

The formal public consultation period for this substance is over. However, if you have a potential alternative, you can find the list of applicants/authorisation holders from our current consultations page, or you can browse for previous consultations. We also recommend checking our list of downstream uses covered by granted authorisations where you can find potential candidates for alternatives.


Technical description:

Trichloroethylene (TCE) is used as an extraction solvent in the industrial manufacture of caprolactam from cyclohexanone. Conditions of use: TCE is used in a continuous, closed-loop, solvent extraction process to recover caprolactam from a two-phase aqueous system comprised of caprolactam in water (containing 70-72% caprolactam, termed raw lactam) and ammonium sulphate (containing 0.8% caprolactam). Caprolactam is subsequently back-extracted into demineralised water and the TCE is recycled and partially regenerated by distillation. Ammonium sulphate is a by-product of the process. Approximately 100 tonnes per year of TCE are used to replace solvent loss from the system and consumption is gradually declining. The closed loop system contains a total of 250 tonnes of TCE. Technical function: Key functional requirements for the solvent used for caprolactam extraction are identified as follows:

  • Extraction efficiency in the range of 90 – 95%
  • Loading capacity for caprolactam in the range of 19 – 20% at 20 °C
  • Viscosity lower than or equal to 0.55 mPa.s at 30 °C
  • Density higher than 1.24 kg/l and different to that caprolactam by at least 0.2 kg/l
  • Water solubility lower or equal to 1.1 g/l at 20 °C
  • Boiling point in the range of 50 – 100 °C to ensure the ready recyclability of the solvent
  • Absence of flammability classification
  • Compatibility with existing feedstock (cyclohexanone oxime in oleum)
  • Compatibility with the continued generation of ammonium sulphate by-product

About applications for authorisation:

Authorisation is one of the processes under the EU chemicals legislation, REACH, for managing the risks of hazardous substances. It aims to ensure that risks from substances of very high concern (SVHCs) are properly controlled and that these substances are progressively replaced by suitable alternatives, without introducing unwanted disruptions to the functioning of the internal market. It is possible to apply for an authorisation for a substance included in the Authorisation List (i.e. Annex XIV of the REACH Regulation).

More about the applications for authorisation process


About public consultations on alternatives:

The purpose of public consultations is to gather additional relevant and meaningful information on possible alternatives for the uses applied for. It offers the opportunity for public engagement in the regulatory process.

The information submitted will be taken into account in the development of the opinion for the relevant applications for authorisation by ECHA’s Committee for Risk Assessment (RAC) and the Committee for Socio-Economic Analysis (SEAC). 


About ECHA:

ECHA is the driving force among regulatory authorities in implementing the EU's ground-breaking chemicals legislation for the benefit of human health and the environment as well as for innovation and competitiveness. ECHA helps companies to comply with the legislation, advances the safe use of chemicals, provides information on chemicals and addresses chemicals of concern.

Alternative should replace

Trichloroethylene (EC# 201-167-4 CAS# 79-01-6) Used as an extraction solvent in caprolactam production.

European Chemicals Agency
European Chemicals Agency

Approximate quantity requested: 100 tonnes /year
Technical Function
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