1,2-Diaminocyclohexane (1,2-DACH), with the chemical formula C₆H₁₄N₂, is an important alicyclic diamine compound. At ambient temperature, it appears as a colorless to pale yellow transparent liquid with an ammonia-like odor. As the hydrogenation product of o-phenylenediamine, it exists in two geometric isomeric forms, cis and trans. Owing to the chair conformation of the cyclohexane ring, the trans isomer further comprises a pair of enantiomers. 1,2-Diaminocyclohexane exhibits excellent chemical stability and reactivity, and is widely used in epoxy resin curing agents, pharmaceutical intermediates (e.g., in the synthesis of oxaliplatin), agrochemicals, dyes, and the preparation of high-performance polymers. With the advancement of the domestic production of adiponitrile, the supply of 1,2-diaminocyclohexane as a by-product has become increasingly abundant, further broadening its application prospects.     General Information Item Details Chemical name 1,2-Diaminocyclohexane CAS No. 694-83-7 Synonyms 1,2-Diaminocyclohexane, 1,2-DACH Applications Chemical industry, pharmaceuticals, agrochemicals     Physical Properties At ambient temperature, 1,2-diaminocyclohexane is a clear, colorless to pale yellow transparent liquid with a faint ammonia-like odor. Its relative density is approximately 0.931 g/cm³, with a melting point range of 41–45 °C, a boiling point of 188–192 °C, and a flash point of 76 °C. The compound is sensitive to air; prolonged exposure may lead to oxidation and yellowing of the product. It is readily soluble in water and also soluble in organic solvents such as ethanol.     Chemical Properties The molecule of 1,2-diaminocyclohexane contains two primary amino groups, conferring typical aliphatic amine chemical properties, including basicity and nucleophilicity. Due to the adjacent positioning of the two amino groups (at the 1,2-positions), it exhibits unique coordination capability, forming stable chelates with various metal ions. The compound displays stereoisomerism, existing predominantly in cis and trans configurations. In the cis isomer, the two amino groups are oriented on the same side of the cyclohexane ring plane; in the trans isomer, they are on opposite sides. The trans-1,2-diaminocyclohexane, being chiral, exists as a pair of enantiomers, (1R,2R) and (1S,2S), among which (1R,2R)-(-)-1,2-DACH is of significant value in pharmaceutical synthesis.     Preparation Methods Hydrogenation of o-Phenylenediamine The industrial production of 1,2-diaminocyclohexane is primarily achieved via the catalytic hydrogenation of o-phenylenediamine. The reaction is typically carried out in an autoclave or a trickle-bed reactor using metal catalysts such as ruthenium (Ru) or nickel (Ni). During the process, the benzene ring of o-phenylenediamine is saturated to yield 1,2-diaminocyclohexane. The ratio of cis to trans isomers in the product can be controlled by adjusting reaction conditions, including temperature, pressure, and catalyst type. Co-production Process In the hydrogenation of adiponitrile to produce hexamethylenediamine, certain amounts of specialty amines such as 1,2-diaminocyclohexane and cyclohexylimine are generated as by-products. With the commissioning of domestic adiponitrile production facilities, this co-production route has become an important source of 1,2-diaminocyclohexane, contributing to cost reduction and improved resource utilization.     Applications Epoxy Resin Curing 1,2-Diaminocyclohexane is a novel and highly efficient curing agent for epoxy resins. It features low dosage requirements, cost-effectiveness, and rapid curing speed. Epoxy resins cured with 1,2-diaminocyclohexane exhibit excellent chemical resistance, heat resistance, and mechanical properties, and are widely used in wind power structural adhesives, electronic encapsulation materials, and high-performance coatings. Pharmaceutical Synthesis In the pharmaceutical field, 1,2-diaminocyclohexane serves as a key intermediate in the synthesis of various drugs. In particular, (1R,2R)-(-)-1,2-diaminocyclohexane is a critical ligand precursor for the anticancer drug oxaliplatin. Additionally, it is employed in the synthesis of other biologically active heterocyclic compounds. Other Applications 1,2-Diaminocyclohexane is also utilized in the synthesis of various agrochemicals and dyes. In the agrochemical sector, it serves as an intermediate in the synthesis of carbamate herbicides and other heterocyclic fungicides. In the dye industry, it is used in the preparation of specific azo dyes and functional auxiliaries. As a monomer or chain extender, 1,2-diaminocyclohexane can also be used in the preparation of high-performance polymers such as polyamides and polyurethanes, with its alicyclic structure imparting excellent weatherability and anti-yellowing properties to the resulting polymers.