Design,Synthesis And Evaluation Of Acylphosphine Oxide Photoinitiators

2,4,6-Trimethylbenzoyldiphenylphosphine oxide(TPO)is a typical representative of acylphosphine oxide photoinitiators.The common synthesis of TPO has the problems of harsh reaction condition,huge consumption of solvent,hardly handled by-products.Thus,one-step synthesis of TPO was explored in this thesis.Optimum reaction conditions were obtained through investigation of solvent,reaction time,reaction temperature,material ratio,addition of base and side reaction:diphenylphosphine oxide(DPO)and 2,4,6-trimethylbenzoyl chloride(TMBC)as raw materials,potassium hydroxide as catalyst,dichloromethane as reaction solvent.The isolated yield of TPO in present method was ca.16%higher than the common synthesis way.On the other hand,to solve the problem of few kinds of visible light photoinitiators,a series of novel acylphosphine oxide photoinitiators were designed and synthesized based on the structure of TPO.Results of light absorption properties of the target products shown that the absorption range of 1-naphthoylbenzoyldiphenylphosphine oxide(1-NPO),2-naphthoylbenzoyldiphenylphosphine oxide(2-NPO),2-methoxy-1-naphthoy ldipheny lphosphine oxide(2-CH3O-1-NPO),4-diphenylaminobenzoyldiphenylphosphine oxide(NAPO)and 4-pyrrolidinylbenzoyl diphenylphosphine oxide(PPO)extended to the visible region and the corresponding molar absorption coefficient are high.Based on this,the performance of 1-NPO,2-NPO,2-CH3O-1-NPO and TPO in photopolymerization were compared.Results shown that all three new curing systems possess higher initiation efficiency than TPO.Besides,the migration rates all three new curing systems were lower than TPO,especially for 2-CH3O-1-NPO(the migration rate is only 1/23 of TPO).All above results reveal that 1-NPO,2-NPO,2-CH3O-1-NPO are highly effective photoinitiator with visible light absorption and low migration rate,which could be the substitutes of TPO and play important roles in the fields of bio-materials or food packaging.