Stabilization of asphaltenes by phenolic compounds extracted from cashew-nut shell liquid

The liquid extracted from cashew-nut shell is composed almost completely of phenolic compounds containing 15-carbon chains with variable unsaturation degrees, meta-substituted in the aromatic ring. The similarity of these com pounds with the structures described as efficient peptizing agents for asph altenes, the crude oil polar fraction, induced us to evaluate cashew-nut sh ell liquid (CNSL) and its derivatives, cardanol and polycardanol, as asphal tene stabilizing agents. The results confirm that CNSL and cardanol have a performance comparable to nonylphenol. Polycardanol was not only less effic ient than its monomer, but, instead, enhanced the precipitation of asphalte nes. This effect may be ascribed to the large number of phenol groups prese nt in the polymer that may flocculate the asphaltene particles or increase its polarity, reducing its solubility in aliphatic solvents. (C) 1999 John Wiley & Sons, Inc.