A new kind of oligomer was synthesized by using resorcinol and acetone as reactants in the presence of acidic catalyst.The molecular mass of resultant oligomers investigated by GPC ranged from 840 to 1320 with the variation of the molar ratio of acetone to resorcinol in the reaction system.Firstly

based on the analysis of 1H NMR and 13C NMR spectra

the hydrogen atom located on the site 2 in the benzene ring of resorcinol could not react in the synthesis of oligomer because of steric hindrance which made the reactivity of hydrogen atom in the position of 2 considerably lower than that of hydrogen atoms in the position of 4 or 6 in the resorcinol.Therefore

the functionality of resorcinol here was confined to be 2.On the other hand

the analytical result of the gravimetric method showed that the molar ratio of acetone to resorcinol in the oligomer was always smaller than 2 even if the amount of acetone was in excess of 5 times of resorcinol in the reaction system.Additionally

the oligomer had favorable solubility in ordinary organic solvents such as ethanol

acetone

THF and so on.Consequently

the resultant oligomer was linear

rather than network.Secondly

the unit structures of the oligomer were proposed according to the analysis of the FT-IR spectrum.Finally

a reasonable mechanism of the reaction of acetone with resorcinol catalyzed by acid was put forward which could explain the process of the reaction of acetone with resorcinol well.