Purification of creosol applying green heterogeneous extraction technology

Abstract

BACKGROUND: Cresol is an important industrial raw material, which is mainly derived from lignocellulosic biomass. High-purity creosol can significantly improve the quality of its downstream product. The extraction of creosol with ultra-high purity (>99.5%) and low cost has attracted extensive attention in recent years. A new and simple green heterogeneous extraction technology for separating ultra-high-purity creosol is proposed in this paper.RESULTS: When a certain amount of creosol is gradually dripped into Ca 2+ solution, the chemicals in three reaction stages are successively monitored by in situ Fourier transform infrared spectroscopy. The molar ratio of creosol and Ca 2+ in the endproduct of this reaction reaches four. Three different chemical bonds in three reaction stages are successively monitored: ion bond, coordination bond formed by ionic compound, and coordination bond formed by creosol molecule. This collected end-product can be decomposed easily. The vapors released in this decomposed process is determined to be high-purity creosol. Meanwhile, the molar ratio of creosol to Ca 2+ in the residual solid after decomposition of the end-product reduces to two.CONCLUSION: Based on the reaction mechanism between Ca 2+ and creosol, a new route for the separation and purification of creosol was proposed in this study. The creosol extraction rate reached 91.5% when excessive Ca 2+ solution was added to the creosol solution. The purity of creosol reaches up to 99.7% when the end-product of the reaction between Ca 2+ and creosol is decomposed at 170 °C.

Recovery of high‐purity‐4‐chloroguaiacol from bleaching wastewater by a heterogeneous extraction method

“…Then, one mole of intermediate can react with two moles of phenolic compounds again in the next extraction process of phenolic compounds. 41,42 Luo et al obtained above 99.5% purity 4-ethyl guaiacol from the phenolic wastewater based on the heterogeneous extraction technology. 43 Considering that the heterogeneous extraction technology has such a high selectivity and directional extraction for phenolic compounds, it may be used to extract 4-chloroguaiacol in bleaching wastewater.…”

“…Meanwhile, high purity phenolic compound was simultaneously discharged and collected in a downstream cooling system. Then, one mole of intermediate can react with two moles of phenolic compounds again in the next extraction process of phenolic compounds 41,42 . Luo et al obtained above 99.5% purity 4‐ethyl guaiacol from the phenolic wastewater based on the heterogeneous extraction technology 43 .…”