1,2-Cyclohexane dicarboxylic acid diisononyl ester is a plasticizer for the manufacture of flexible plastic articles in sensitive application areas such as toys, medical devices and food packaging. From a chemical point of view it belongs to the group of aliphatic esters.
In 2002 BASF started selling 1,2-cyclohexane dicarboxylic acid diisononyl ester under the tradename of Hexamoll DINCH as an alternative for phthalate plasticizers.
The two commercial routes to manufacture 1,2-cyclohexane dicarboxylic acid diisononyl ester are the catalytic hydrogenation of diisononyl phthalate and the Diels-Alder reaction of a maleic acid ester with 1,3-butadiene followed by hydrogenation. In the case of the catalytic hydrogenation the aromatic part of the diisononyl phthalate is transformed to a cyclohexane ring by a formal addition of 6 hydrogen atoms while the alkyl and ester groups are not affected by the hydrogenation.
In the European Union the European Food Safety Authority has approved 1,2-cyclohexane dicarboxylic acid diisononyl ester for a wide variety of food contact applications in October 2006. In 2007 1,2-cyclohexane dicarboxylic acid diisononyl ester has been added to Annex III of the "Directive 2002/72/EC relating to plastic materials and articles intended to come into contact with food". The EU Directive 2002/72 has meanwhile been superseded by Regulation (EU) No. 10/2011. Hexamoll DINCH had been included by its chemical name in “Recommendations” I.
A US federal law was passed in 2008 banning the use of some phthalates in children's toys. When the law took effect in February 2009, Mattel and Learning Curve confirmed to NPR they were substituting phthalates with Hexamoll DINCH and citrate-based plasticizers.
In the European Union 1,2-cyclohexane dicarboxylic acid diisononyl ester is not listed in directive 2005/84/EC which bans the use of certain phthalates in toys and childcare articles and thus can be used safely in toy and childcare articles.
A research group from Harvard and CDC stated that "the potential health effects from DINCH exposure remain largely unknown". Their research at a fertility clinic showed that women who had been exposed to DINCH had lower estradiol hormone levels and fewer oocytes in their ovaries.
According to the Swedish Environmental Research Institute "children's exposure to DINCH should be investigated in more detail and exposure to the general population should be closely monitored."
The Chronic Hazard Advisory Panel of the U.S. Consumer Product Safety Commission "strongly encourages the appropriate U.S. agencies to obtain the necessary toxicological and exposure data to assess any potential risk from DINX" because of "lack of publically [sic] available information".
According to a panel appointed by the French Agency for the Safety of Health Products (ANSM), there is very little clinical assessment data regarding the toxicity, migration from Medical Devices and population exposure of alternative plasticizers (e.g. DINCH/DINX) and their metabolites.
A report by the Danish Ministry of the Environment states that DINCH/DINX may be a possible endocrine disruptor but further research is needed to evaluate the risk.
Toxicogenomic screening showed that 648 genes were significantly changed after 48 hours exposure to DINCH suggesting that "DINCH is biologically active".