Study On The New Process Of The Synthesis Of Saligenin

Saligenin (OHA) is an important fine chemical product, which is widely used in the synthesis of pesticide, medicine, spice, cosmetic and so on. In this paper, a new process was developed to synthesize OHA with phenol, boric acid, and paraformaldehyde (PF) as raw materials, which including such steps, namely as dehydration, esterification, hydroxymethylation, hydrolyzation,decompress-distillation and crystallization. The advantages of this approach lie in its cheap raw materials, less pollution to the environment over others. In the step of esterification, dehydration of boric acid and then esterifying with phenol were carried out in order to increase conversion of esterification. Effect of reaction temperature, consumption of boric acid, kinds and amount of dehydrolating agent on the yield of esterification were studied. The experimental results showed that high conversion of 98% of esterification was obtained.In the step of hydroxymethylation, (di-)n-butyl ether was used as solvent, and solid formaldehyde, which was decomposed by paraformaldehyde, was conducted into the reactor. Orthogonal test was designed to investigate the factors of reaction temperature, reaction time, amount of solvent and consumption of PF on the hydroxymethylation. The results show that the reaction temperature has significant influences on the yield of OHA, others seem to have less effect. It is worthy to note that (di-)n-butyl ether may also used as a good extraction solvent of OHA in the following separation steps.The influences of various factors on the yield of OHA were also investigated in hydrolyzation step and sodium bicarbonate abstersion step. The refined OHA was finally manufactured by decompress-distillation and crystallization. HPLC analysis of final product was conducted and showed that the purity of the OHA was above 99% and the maximum yield of OHA was up to 64%.