Kinetics for etherification of sodium o-nitrophenoxide via third-liquid phase-transfer catalysis

The novel method for synthesizing o-nitrophenyl octyl ether from the etherification of sodium o-nitrophenoxide and 1-bromooctane was investigated via third-liquid phase-transfer catalysis (TLPTC). The volume of the third-liquid phase formed increases with increasing the amount of catalyst employed, and about 91.2% of tetrabutylammonium bromide (TBPB) was accumulated in the third-liquid phase by adding 0.07 mol of NaOH, leading to a higher reactivity. The product yield greater than 98% was obtained within 3 h of reaction using TBPB at 80 degrees C. The variations of the catalytic intermediate in the third-liquid phase during reaction were explored. The consumption rate of the catalytic intermediate increased with the increase of reaction rates. The enhancement factor (eta) of the catalytic intermediate in third-liquid phase can be correlated as a linear function of the product yield (Y) in the organic phase as eta = alpha(1) - alpha Y-2. Based on the experimental observations, a kinetic model of pseudo-first-order was proposed to successfully describe the overall reaction with the apparent activation energy to be 23.32 kcal/mol for 0.003 mol of TBPB used. The interfacial phenomenon affected by catalytic intermediate and catalyst was also performed. The third-liquid phase-transfer catalysis is demonstrated as an effective method to synthesize specialty chemicals. (c) 2005 Elsevier B.V. All rights reserved.