Research On The Synthesis Of Carbazole Derivative Photoinitiator

UV-curing technology was widely used in many fields for its great benefits in low energy consuming,environment protection and high-efficiency manufacture, including post and telecommunications,print and package,computer,electronics and upholster,among which photoinitiators played the most important role.Especially,a new kind of two-photon photoinitiators emerged recently with a carbazole substructure exhibited excellent character for its large two-photon absorption cross section.In this thesis,a new photoinitiator with a carbazole oxime ester substructure named 1-{6-(o-methyl benzoyl)-N-ethylcarbazol-3-yl}-ethane-1-one oxime O-acetate was synthesized through a reasonable route and all the process was optimized.The results provided theoretical and practical experiences for the synthesis of other carbazole derivative photoinitiators.The concrete operating procedures were shown as follows.Firstly,3-acetyl-6-(o-methyl benzoyl)-N-ethylcarbazole was prepared by successive o-methyl benzoylation and acetylation,with N-ethylcarbazole as substrate, o-methyl benzoyl chloride and acetyl chloride as acylating agents,and AlCl₃ as catalyst.In o-methyl benzoylation,there was no need for AlCl₃ to be used as equimolar as the substrate to ensure the complete conversion of the substrate and the diacylation was avoided.Besides,the one-pot acylation reduced the dosage of AlCl₃, and thus made an easy workup process and eased the pollution caused by AlCl₃.Secondly,with the aid of sodium acetate,3-acetyl-6-(o-methyl benzoyl)-N-ethyl carbazole underwent an oximation with hydroxylamine hydrochloride to form 1-{6-(o-methyl benzoyl)-N-ethylcarbazol-3-yl}-ethane-1-one oxime.Since the by-product acetic acid in the oximation could be used as ester reagent of subsequent esterification.Thus,1-{6-(o-methyl benzoyl)-N-ethylcarbazol-3-yl}-ethane-1-one oxime O-acetate was prepared in another one-pot process,in which the oximation and esterification were combined.The waste acetic acid was utilized as resource, contamination was reduced from root. 1-{6-(o-methyl benzoyl)-N-ethylcarbazol-3-yl}-ethane-1-one oxime O-acetate was prepared in 76.9%yield with a purity of 99.1%proved by HPLC and its structure was confirmed by ¹H-NMR,¹³C-NMR and IR.