Production and separation of value-added compounds from pine wood using pyrolysis and biorefinery techniques

Value-added compounds were obtained from pine wood bio-oil, converting it into a renewable source for several chemicals: acids (acetic acid), sugars (levoglucosan), furan derivatives (furfural) and phenolics (catechol, phenol, 4-propylguaiacol, vanillin). To achieve this, firstly a comparison of a direct pyrolysis at 500 °C versus a two-staged pyrolysis (300 °C and 500 °C) was made. It was determined that a two-staged pyrolysis ensue in the obtainment of less complex liquid fractions since it concentrates families of compounds in different phases of bio-oil, facilitating their subsequent separation. Secondly, two methodologies (A and B) were designed to establish a procedure for separating the various chemical groups present in bio-oil. Methodology A consisted of a first vacuum distillation followed by an extraction process that combined an alkaline extraction and a simple extraction with ethyl acetate. Methodology B consisted of a first extraction with trioctylamine and ethyl acetate followed by a vacuum distillation and an extraction with hot water. The results showed that methodology A was better for the separation of chemical compounds from bio-oil, obtaining one fraction with the carboxylic acid content and furan derivatives, a second fraction containing the phenolic compounds and a third fraction enriched with the sugar content.