Sherif Farag

Extraction of phenols from lignin microwave-pyrolysis oil using a switchable hydrophilicity solvent.

Microwave pyrolysis of lignin, an aromatic polymer byproduct from paper-pulping industry, produces char, gases, and lignin pyrolysis oil. Within the oil are valuable phenolic compounds such as phenol, guaiacol and catechol. In this work, we describe a method using switchable hydrophilicity solvents (SHS) to extract phenols as a mixture from lignin microwave-pyrolysis oil at the scale of 10 g of bio-oil. Even at this small scale, losses are small; 96% of the bio-oil was recovered in its three fractions, 72% of guaiacol and 70% of 4-methylguaiacol, the most abundant phenols in the bio-oil, were extracted and 91% of the solvent SHS was recovered after extraction. The starting material (lignin microwave-pyrolysis oil) and the three fractions resulted from SHS extraction were characterized by GC-MS and quantitative (13)C{(1)H} and (31)P{(1)H} NMR spectroscopy.

Economics evaluation for on-site pyrolysis of kraft lignin to value-added chemicals.

This work is part of a series of investigations on pyrolysis of lignin. After obtaining the necessary information regarding the quantity and quality of the obtained products, a first step economics evaluation for converting lignin into chemicals was essential. To accomplish this aim, a pyrolysis plant with a 50t/d capacity was designed, and the total capital investment and operating costs were estimated. Next, the minimal selling price of the obtained dry oil was calculated and the effect of crucial variables on the estimated price was examined. The key result indicates the estimated selling price would not compete with the price of the chemicals that are fossil fuel based, which is primarily due to the high cost of the feedstock. To overcome this challenge, different scenarios for reducing the selling price of the obtained oil, which consequently is helping by taking a place among the fossil fuel based chemicals, were discussed.

Supercritical fluid rectification of lignin pyrolysis oil methyl ether (LOME) and its use as a bio-derived aprotic solvent

Lignin oil methyl ether (LOME) is a bio-derived solvent obtained from lignin by pyrolysis, methylation, and rectification. It performs well as an alternative polar aprotic solvent for organic reactions such as the Menschutkin synthesis of quaternary amines. Methylation of lignin pyrolysis oil was achieved using dimethylcarbonate under mild reaction conditions. The resulting methylated oil was subjected to supercritical fluid rectification in supercritical CO2, yielding LOME (90 wt% of eight identified veratroles and anisoles) which can be directly used as a bio-derived aprotic solvent.