A method for producing bis(aminomethyl)cyclohexane, including hydrogenating xylylenediamine in the presence of a solvent and a catalyst, wherein the catalyst with decreased activity due to use is treated in a catalyst regeneration treatment step including the following step (1) and step (2), and then reused in a reaction system: step (1): maintaining an amount of bis(aminomethyl)cyclohexane in a liquid before the step (2) at 20% by mass or less, step (2): heating the catalyst to 100 to 500° C. and bringing the catalyst into contact with a hydrogen-containing gas.

A method for producing bis(aminomethyl)cyclohexane, including hydrogenating xylylenediamine in the presence of a solvent and a catalyst, wherein the catalyst with decreased activity due to use is treated in a catalyst regeneration treatment step including the following step (1) and step (2), and then reused in a reaction system: step (1): maintaining an amount of bis(aminomethyl)cyclohexane in a liquid before the step (2) at 20% by mass or less, step (2): heating the catalyst to 100 to 500° C. and bringing the catalyst into contact with a hydrogen-containing gas.

A method for producing bis(aminomethyl)cyclohexane, including hydrogenating xylylenediamine in the presence of a solvent and a catalyst, wherein the catalyst with decreased activity due to use is treated in a catalyst regeneration treatment step including the following step (1) and step (2), and then reused in a reaction system: step (1): maintaining an amount of bis(aminomethyl)cyclohexane in a liquid before the step (2) at 20% by mass or less, step (2): heating the catalyst to 100 to 500° C. and bringing the catalyst into contact with a hydrogen-containing gas.

A method for preparing a dicyanoalkane may omit a filtration for a catalyst after a cyanation reaction can by carrying out the cyanation reaction in a state in which precipitation of a metal catalyst is suppressed. A method for preparing a dicyanoalkane may involve cyanating one or more aliphatic dicarboxylic acids and/or salt(s) thereof with an ammonia source in the presence of a predetermined compound and a catalyst, wherein, in the cyanation, the amount of the predetermined compound is maintained at a predetermined amount or more with respect to the catalyst.

A method for preparing a dicyanoalkane may omit a filtration for a catalyst after a cyanation reaction can by carrying out the cyanation reaction in a state in which precipitation of a metal catalyst is suppressed. A method for preparing a dicyanoalkane may involve cyanating one or more aliphatic dicarboxylic acids and/or salt(s) thereof with an ammonia source in the presence of a predetermined compound and a catalyst, wherein, in the cyanation, the amount of the predetermined compound is maintained at a predetermined amount or more with respect to the catalyst.

In the embodiments, an aqueous hydrochloric acid solution and an organic solvent instead of hydrogen chloride gas and solid triphosgene instead of phosgene gas may be used in the process of preparing a diisocyanate from a diamine through a diamine hydrochloride. In addition, the embodiments provide processes for preparing a diisocyanate composition and an optical lens, which are excellent in yield and quality with mitigated environmental problems by controlling the total content of metals, cations, or anions in a diamine hydrochloride composition.

In the embodiments, an aqueous hydrochloric acid solution and an organic solvent instead of hydrogen chloride gas and solid triphosgene instead of phosgene gas may be used in the process of preparing a diisocyanate from a diamine through a diamine hydrochloride. In addition, the embodiments provide processes for preparing a diisocyanate composition and an optical lens, which are excellent in yield and quality with mitigated environmental problems by controlling the total content of metals, cations, or anions in a diamine hydrochloride composition.

A production method for a cyclohexanedicarboxylic acid compound, having a step of obtaining a cyclohexanedicarboxylic acid compound or an aqueous ammonia solution of a cyclohexanedicarboxylic acid compound by bringing a phthalic acid compound in an aqueous ammonia solution into contact with hydrogen in the presence of a fixed bed catalyst in a reactor.

A production method for a cyclohexanedicarboxylic acid compound, having a step of obtaining a cyclohexanedicarboxylic acid compound or an aqueous ammonia solution of a cyclohexanedicarboxylic acid compound by bringing a phthalic acid compound in an aqueous ammonia solution into contact with hydrogen in the presence of a fixed bed catalyst in a reactor.

The problem addressed by this invention is to achieve a useful and novel method for producing dicyanocyclohexane and bis(aminomethyl)cyclohexane. This problem was solved by providing a method for producing dicyanocyclohexane having a cyanation step in which dicyanocyclohexane is obtained by a cyanation reaction of cyanocyclohexane-1-carboxylic acid and/or a salt thereof with an ammonia source, and a method for producing bis(aminomethyl)cyclohexane using the dicyanocyclohexane thus produced.