Novel microwave synthesized biomass derived furanics as effective sustainable antifouling agents

Abstract

The solid phase microwave-assisted eco-efficientsynthesis of phenyl esters with acid halides including furoylchloride (FO) and thiophenecarbonyl chloride (FS) was achievedin this work. A stoichiometric amount of the correspondingchloride was sufficient to carry out the reaction with yieldsbetween 90% and 95% in 5 min, with simple products purificationby recrystallization in ethanol. In the search of new sustainablealternatives to copper-based antifouling paints, eight compoundswere synthesized, e.g., 2-isopropyl-5-methylphenyl thiophene-2-carboxylate (1), 2-isopropyl-5-methylphenyl furan-2-carboxylate(2), phenyl thiophene-2-carboxylate (3), phenyl furan-2-carbox-ylate (4), 4-methylphenyl thiophene-2-carboxylate (5), 4-methyl-phenyl furan-2-carboxylate (6), 3,4-dimethylphenyl thiophene-2-carboxylate (7), and 3,4-dimethylphenyl furan-2-carboxylate (8).Their antifouling activity was evaluated in field trials. Field antifouling tests carried out at Mar del Plata harbor for 90 days showedthat, except for compound (8), all bioderived furanics were effective in strongly reducing the settlement of the most conspicuousworldwide calcareous macrofouler Balanus amphitrite.