A Continuous Reactive Distillation Process for Citric Acid Esterification




Depletion of fossil fuel resources, coupled with heightened awareness of environmental and health concerns, is providing impetus to search for alternative materials that are biocompatible, biodegradable, and based on renewable resources.  Organic acids produced by fermentation of carbohydrate feedstocks constitute an important class of biorenewable platform chemicals that can be further converted to useful products. Tri-ethyl citrate, produced from citric acid and ethanol, is a non-toxic, biocompatible plasticizer that can be used in place of petroleum-based phthalate compounds. Phthalates have potential carcinogeneity and overall health concerns to the extent that they have been banned in Europe from use in children's toys and human contact applications. The potential application of tri-ethyl citrate as a plasticizer is currently limited by the lack of large-scale, efficient, and economic production facilities.


Description of Technology


This technology is a continuous process for the formation of triethyl citrate using cationic exchange resins as catalysts in a reactive distillation column.  Triethyl citrate is a non-toxic, water-soluble, biocompatible plasticizer that could be used instead of petroleum-based phthalate compounds that are potential carcinogens.


Key Benefits

  • Continuous process,
  • Economical, scale-able process
  • Reaction conditions are relatively modest
  • Green, non-toxic raw material



  • Bioplastics
  • Food additive
  • Plasticizer
  • Humectant
  • Fragrance carrier


Patent Status


US patent: US7,667,068




Navinchandra Asthana, Dennis Miller, Aspi Kolah, Carl Lira, Dung Vu


Tech ID




Patent Information:

For Information, Contact:

Thomas Herlache
Assistant Director
Michigan State University