Preparation And Application Of Specical Imidazole Curing Agent

This thesis is about some curing agents of epoxy resin which own special imidazolestructure. They are1-aminoethyl-2-methylimidazole,2-undecylimidazole,2-heptadecylimidazole, and2-(4-hydroxyphenyl)-4,5-dimethyl imidazole. The methods ofpreparing such compounds as well as in the epoxy resin curing applications was carefullystudied.1-Aminoethyl-2-methylimidazole was synthesized from diethylenetriamine and aceticacid by cyclization, catalytic dehydration and hydrolysis reaction. The chemical structure wascharacterized by FT-IR,1H-NMR and MS. The experiment showed that whenn(diethylenetriamine)∶n(acetic acid)=1∶2, elevating temperature to200℃, the productwas N-(2-methyl-2-imidazolinyl)ethyl acetamide with the yield of92.3%. The next reactionwas dehydration of imidazoline to imidazole with Raney-Ni. The yield of this reaction was94.0%. Finally,1-Aminoethyl-2-methylimidazole could be obtained by hydrolysis reaction ofN-(2-methyl-2-imidazolyl)ethyl acetamide with HCl and the yield was84.8%.2-Undecylimidazole was synthesized from ethylenediamine and lauric acid bycyclization and catalytic dehydration. The chemical structure was characterized by FT-IR,1H-NMR and MS. The experiment showed that when n(ethylenediamine)∶n(lauric acid)=15∶3, elevating temperature to200℃, the product was2-undecylimidazoline with the yieldof85.7%. The next reaction was dehydration of imidazoline to imidazole with Raney-Ni. Theyield of this reaction was96.4%.2-Heptadecylimidazole was synthesized from ethylenediamine and stearic acid bycyclization and catalytic dehydration. The chemical struction was characterized by FT-IR,1H-NMR and MS. The experiment showed that when n(ethylenediamine)∶n(stearic acid)=15∶3, elevating temperature to200℃, the product was2-heptadecylimidazoline with theyield of84.3%. The next reaction was dehydration of imidazoline to imidazole with Raney-Ni.The yield of this reaction was93.7%.2-(4-hydroxyphenyl)-4,5-dimethyl imidazole was synthesized from2,3-butanedione,ammonia and4-hydroxybenzaldehyde by Debus–Radziszewski imidazole synthesis. Theexperiment showed that when elevating temperature to50℃, ammonia carbonate offering the ammonia, the product was2-(4-hydroxyphenyl)-4,5-dimethyl imidazole with the yield of66.5%. The experiment showed that the compounds mixed with epoxy resin after heating,some excellent products can be obtained.Finally, some preparing work were done about1-aminopropyl-2-methylimidazole. Itwas synthesized from1-cyanoethyl-2-methylimidazole. We plan to find the amount ofRaney-Ni, hydrogenation temperature, hydrogenation pressure and get the best process ofprepearing1-aminopropyl-2-methylimidazole.