A Synthesis Method of 2-hydroxy-4-n-octaoxybenzophenones( I )

Under the reaction of KOH, adding a little bit of phase transfer agent, the ultra - violet absorbant 2-Hydroxy-4-n-octaoxybenzophenones can be prepared by the reacting of 2,4-dihydroxybenzophenone with 1-bromooctane. The quality of this product can be improved significantly by adding some water - soluble organic solvent into the reaction system. Experiment shows that dimethyl sulfoxide gives better results. The influences of various surfactants on this reaction are emphatically investigated. These surfactants are methyl sulfate octadecyltrimethylbenzylammonium, dihexadecyldimethylammonium chloride, include:chloro - alkyl trimethyl ammonium, ammonium dodecyl benzene sulfonate, sodium octadecylmethyl sulfate. The effects of some industrial emulsifiers and polyethylene glycol (PEG) on this reaction are studied, It is found by experiment that the purity and yield of 2-hydroxy-4-n-octaoxybenzophenones reach 88.5% and 93.2% respectively by adding 0.8% dihexadecyldimethylammonium chloride (by weight of water) into the reaction mixture. The color of product is yellow. Dihexadecyldimethylammonium chloride is an ideal phase transfer agent.