Abstract
Kinetics of the tryptophan-ninhydrin reaction at a constant [Triton X-100] (= 50.0 (X) 10(-3) mol dm(-3)) and pH (= 5.0), maintained by CH3COONa-CH3COOH, in presence of different organic solvents, i.e. methylcellosolve, dimethylsulfoxide, acetonitrile and 1-propanol, has been studied spectrophotometrically at 40 degrees C. In each case, the pseudo-first-order rate constant increases with increase in the proportion of organic solvent. The catalytic role of solvents has been discussed in terms of increasing the solubility of Rultemann's purple (the product) in the solvents and blocking the side reaction. Other reasons for the catalytic role of solvents have also been discussed.