Isophorone is an α,β-unsaturated cyclic ketone. It is a colorless liquid with a characteristic peppermint-like odor, although commercial samples can appear yellowish. Used as a solvent and as a precursor to polymers, it is produced on a large scale industrially.[4]
Isophorone undergoes reactions characteristic of an α,β-unsaturated ketone. Hydrogenation gives the cyclohexanone derivative. Epoxidation with basic hydrogen peroxide affords the oxide.[5]
When exposed to sunlight in aqueous solutions, isophorone undergoes 2+2 photocycloaddition to give three isomeric photodimers (Figure). These "diketomers" are cis-syn-cis, head to tail (HT), cys-anti-cys (HT), and head-head (HH). The formation of HH photodimers is favored over HT photodimers with increasing polarity of the medium.[7]
The partly hydrogenated derivative trimethylcyclohexanone is used in production of polycarbonates. It condenses with phenol to give an analogue of bisphenol A. Polycarbonates produced by phosgenation of these two diols produces a polymer with improved thermal stability.[9] Trimethyladipic acid and 2,2,4-trimethylhexamethylenediamine are produced from trimethylcyclohexanone and trimethylcyclohexanol. They are used to make specialty polyamides. Hydrocyanation gives the nitrile followed by reductive amination gives isophorone diamine. This diamine is used to produce isophorone diisocyanate which has certain niche applications.[4]
The LD50 value of isophorone in rats and rabbits by oral exposure is around the 2.00 g/kg.[10] The safety aspects of isophorone have been subject to several studies.[11]
The use of isophorone as a solvent resulted from the search for ways to dispose of or recycle acetone, which is a waste product of phenol synthesis by the Hock method.[12]
^Richard L. Wasson; Herbert O. House (1957). "Isophorone Oxide". Org. Synth. 37: 58. doi:10.15227/orgsyn.037.0058.
^"TOXNET". toxnet.nlm.nih.gov. Archived from the original on 2017-10-24. Retrieved 2016-03-11.
^Gonçalves, Huguette; Robinet, Germaine; Barthelat, Michèle; Lattes, Armand (1998-01-28). "Supramolecularity and Photodimerization of Isophorone: FTIR and Molecular Mechanics Studies". The Journal of Physical Chemistry A. 102 (8): 1279–1287. Bibcode:1998JPCA..102.1279G. doi:10.1021/jp9729270.
^W. Morton Grant, Joel S. Schuman M.D (11 February 2016). "Toxicology of the Eye: Effects on the Eyes and Visual System from Chemicals, Drugs, Metals and Minerals, Plants, Toxins, and Venoms; Also, Systemic Side Effects from Eye". Med (2-Volume Set) 4th Edition, Page 863.
