| 简介 |
FIELD : chemistry.SUBSTANCE : present invention relates to an improved method of producing 3-aminomethyl-3, 5, 5-trimethylcyclohexylamine (that is, to production of isophorone diamine). Isophorone diamine is used to obtain isophorone diisocyanates or polyamides as curing agent for epoxy resins. Method of producing 3-aminomethyl-3, 5, 5-trimethylcyclohexylamine includes steps a) reaction of 3-cyano-3, 5, 5-trimethylcyclohexanone with NH3 to produce a product containing 3-cyano-3, 5, 5-trimethylcyclohexylamine; b) mixing product obtained at step a), with basic compound in presence of hydrogen, NH3 and first hydrogenation catalyst to produce a product containing 3-aminomethyl-3, 5, 5-trimethylcyclohexylamine and 3-cyano-3, 5, 5-trimethylcyclohexylamine, wherein said basic compound is selected from : oxide, hydroxide or carbonate of alkali metal, or oxide, hydroxide or carbonate of alkali-earth metal, or oxide, hydroxide or carbonate of rare-earth metal, preferably LiOH, NaOH or KOH; c) mixing product obtained at step b), with acid compound in presence of hydrogen, NH3 and second hydrogenation catalyst, wherein content of 3-cyano-3, 5, 5-trimethylcyclohexylamine in product obtained at step b) is 5-20 wt%. Said 3-cyano-3, 5, 5-trimethylcyclohexylamine in product obtained at step b), is converted to 3-aminomethyl-3, 5, 5-trimethylcyclohexylamine, and said acid compound is selected preferably from formic acid or acetic acid. First hydrogenation catalyst used at step b), and said second hydrogenation catalyst used at step c), are identical or different. Preferable are hydrogenation catalysts containing cobalt or nickel, preferably Raney cobalt. Preferred content of 3-cyano-3, 5, 5-trimethylcyclohexylamine in product obtained at step b) is 10-15 wt%. Solvent for acid compound from step c) is water, alcohol or ether, preferably, alcohol, such as methanol or ethanol; and concentration of solution is preferably 1-5 wt%. Step a) is carried out at temperature 20-100 °C and pressure 0.5-30 MPa, preferably at a temperature of 40-60 °C and pressure of 10-30 MPa; step b) is carried out at temperature 50-130 °C and pressure of 10-30 MPa, preferably at a temperature of 60-100 °C and pressure of 15-20 MPa, and step c) is carried out at temperature 50-130 °C and pressure of 10-30 MPa, preferably at a temperature of 100-130 °C and pressure of 15-20 MPa. Step b) and step c) are performed in a reactor for hydrogenation, preferably in tubular reactor and preferably with sprinkled layer.EFFECT : method provides low content of amino nitriles in product, hence, effective reduction of duration of reaction and considerably reduced catalyst consumption during hydrogenation reaction.16 cl, 2 dwg, 4 tbl, 5 ex |
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