KINETICS OF A PHASE-TRANSFER CATALYSIS REACTION IN SUPERCRITICAL-FLUID CARBON-DIOXIDE

The first example of a phase-transfer-catalyzed reaction carried out i n a supercritical fluid (SCF) is reported. The kinetics of the nucleop hilic displacement of benzyl chloride with a bromide ion in SCF solven t CO2 in the presence of acetone cosolvent is presented. In addition, the solubility of tetraheptylammonium bromide (THAB) in SCF CO2 in the presence of acetone cosolvent is reported. The reaction rate was meas ured at 50 and 75 degrees C at pressures to 200 bar; the reaction was found to follow first-order, reversible kinetics for the reactions cat alyzed by THAB and zero-order kinetics for reactions catalyzed by 18-c rown-6.