Kinetic study of synthesizing N-butylphthalimide under solid–liquid phase-transfer catalysis conditions

Abstract

The synthesis of N-butylphthalimide (PTR) from the reaction of 1-bromobutane and potassium salt of phthalimide (PTK) was carried out successfully in a solid–liquid phase-transfer catalytic condition (SL-PTC) instead of reaction in a liquid–liquid two-phase medium. No water is required in the reaction system. The advantage of using SL-PTC to synthesize organic chemicals is to avoid a serious hydration of potassium salt of phthalimide from the reaction of 1-bromobutane and potassium salt of phthalimide in a liquid–liquid two-phase solution. The reaction is greatly enhanced in the solid–liquid solution catalyzed by quaternary ammonium salts. The reaction mechanism is proposed and verified by examining the experimental evidence. A kinetic model is proposed in which a pseudo first-order rate law is sufficient to describe the results. Kinetics of the reaction, including the effects of agitation speed, amount of acetonitrile, organic solvents, amount of tetrabutylammonium bromide, quaternary ammonium salts, amount of water and temperature on the conversion of 1-bromobutane and the apparent rate constant ( k app) were investigated in detail. Rational explanations to account for the phenomena on the results were made.