Pyrolysis of Jatropha Curcas seed cake followed by optimization of liquid–liquid extraction procedure for the obtained bio-oil

• Lignocellulosic biomass pyrolysis oil phase separation.
• Comprehensive liquid-liquid extraction procedure for the separated phases.
• Investigation of prevalent classes of organic chemicals and their distribution.
• GC–MS characterization of compounds.

Lignocellulosic biomass is considered an abundant and renewable source to produce bio-oils with an objective of its value addition for fuels and chemicals. Upgrading strategies have immensely evolved as a result of ever progressing research in this field. Development of complete analytical protocol for bio-oil characterization at different stages of its production, storage, upgrading and during its use is essential for the purpose of its quality assurance and understanding. This report is aimed at developing a sample preparation procedure for bio-oils involving an extensive liquid–liquid extraction approach. Bio-oil obtained after slow pyrolysis of Jatropha Curcas seed cake was phase separated and subjected to solvent extraction. Various solvents were screened for their extraction capabilities towards available organic compounds of all functional group in the bio-oil. Ethyl acetate, dichloromethane, carbon tetrachloride, diethyl ether, benzene, cyclohexane and hexane were employed for extraction of aqueous phase under similar conditions. Recoveries of compounds containing varying functional groups indicated ethyl acetate and dichloromethane as optimum among all other solvents. During the extraction, partitioning of compounds between bio-oil phase and solvent occurred largely on the basis of polarity. Acidic and basic organic compounds present in the aqueous phase were determined after adjusting the pH of samples followed by dichloromethane extraction. A comprehensive detail of the extracted chemicals and their classification has been provided. The identification was carried out qualitatively with GC–MS and derivatization of polar chemicals was also carried out before analysis. These experiments compare the efficacy of various organic solvents for extracting diverse bio-oil pyrolytic products. The findings are important in ascertaining usefulness of organic solvents towards enrichment of available bio-oil chemical groups. The information may be either utilized for characterization purposes or their monitoring during upgrading process.

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