Extraction of cardanol and phenol from bio-oils obtained through vacuum pyrolysis of biomass using supercritical fluid extraction

The feasibility of extraction of phenol rich oil from the bio-oils obtained through pyrolysis of cashew nut shells and sugarcane bagasse is studied. The extraction rate of phenol rich oil using CO2 as a supercritical fluid is discussed. Operating parameters are optimized for the maximum concentration of phenol and cardanol. Higher yield of oil (50% by weight) along with higher concentration of phenols and cardanol by present method is found encouraging. The experiments were conducted in the pressure range of 120–300 bar, the temperature range of 303–333 K and the mass flow rate range of 0.7–1.2 kg/h. The process parameters are optimized to maximize the yield of extracts and its contents of phenols and substituted phenols from sugarcane bagasse pyrolysis oil. The oil samples obtained at various operating parameters are analyzed by Gas Chromatograph–Mass Spectroscopy (GC–MS) and Fourier Transform Infra-Red Spectroscopy (FTIR).

► The process of recovering phenol rich oil, having up to 72% phenols and substituted phenols, using supercritical fluid extraction (SFE) from the pyrolysis oils of bagasse is established.
► Chemical composition of sugarcane bagasse oil (SBO) obtained through SFE route depends on the operating parameters, and that the percentage of phenols increased with increase in pressure.
► Extraction of cardanol from pyro-based cashew nut shell liquid (CNSL) not only gave higher overall yields but also much higher percentage of cardanol in the oil (85%).
► This is higher than that of the technically distilled grade CNSL. In both the cases 300 bar and 333 K gave the maximum yields.