Of various aprotic solvents such as dimethyl sulfoxide, dimethyl formamide, dimethyl acetamide, formyl morpholide, acetyl morpholide, formyl piperazide, acetonitrile, tetrahydrofuran, benzene, and carbon tetrachloride, the first six served as effective solvents for the cyanation of furfuryl chloride . The reaction rates were proportional to the product of dielectric constant and solubility of sodium cyanide rather than either one of the two . In all the solvents tested, isomeric 5-methyl-2-cyanofuran was not formed . When the reaction was conducted in dimethyl formamide, the presence of water ata level less than 2% increased the reaction rates without inducing side reactions.With an water level above 5%, however, the formation of the isomer and the hydrolyzed product, furfuryl alcohol, was accelerated. The effects of the amount of solvent and sodium cyanide and that of reaction temperatures were also studied. The reaction mechanisms may be proposed as follows . The aprotic solvent is probably solvated toward the sodium ion, thus the attack toward furfuryl chloride being disturded On the other hand, CN- keeps its high nucleophilicity and remains free, and the S
N2 reaction is allowed to occur with ease . In the meantime, the polarization of furfuryl chloride is also enhanced by the solvation of polar solvent and thus the desired reaction accelerated.
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