Feasibility analysis of extracting and purifying 4-ethylguaiacol using the intermediate product of the reaction between 4-ethylguaiacol and Ca2+ as the extracting agent

Abstract

A heterogeneous extracting route of 4-ethylguaiacol is constructed using the intermediate of the reaction between 4-ethylguaiacol and Ca2+ as the extracting agent. In this work, 4-ethylguaiacol with different concentrations (70, 80, 90, 95%) is prepared using 40 v/v% ethanol aqueous solution as the mother liquor. The extraction parameters optimization, cycle extraction and 4-ethylguaiacol purification are studied, respectively. Extracting parameters investigated are reaction temperature (4–80 ℃), extraction time (5–60 min), and pH value (6.5–13). 4-ethylguaiacol extraction efficiency keeps above 90% at the optimum extracting conditions at the reaction temperature of 4–20 ℃, the extraction time of 30 min, and the pH value of 6.5–10. Further cycle extraction experiments are carried out under the optimal extraction parameters using the intermediate as the extracting agent. After 36 cycle extraction times, the extraction efficiency of 4-ethylguaiacol can still reach 91.7%. Guaiacol has similar physical and chemical properties to 4-ethylguaiacol, thus it is used as an impurity to test the extraction and purification effect of the heterogeneous extracting method. With increasing the cycle extraction times from 1 to 4, 4-ethylguaiacol purity reaches more than 99% for all four mother liquors with different initial concentrations. 4-ethylguaiacol purity of 99.57% is achieved through twice cycle extraction when its initial content in the mother liquor is 95%.