EFFECTS OF CALCIUM-CHLORIDE ON THE PROTON-TRANSFER DYNAMICS OF 4-HYDROXY-1-NAPHTHALENESULPHONATE IN ALCOHOL WATER MIXTURES/

Proton transfer from the excited 4-hydroxy-1-naphthalenesulphonate to the water solvent is studied in n-alcohol/water (70:30) mixtures in th e presence of calcium chloride. The proton acceptor concentration is f ound to increase initially with an increase in the concentration of ca lcium chloride reaching a maximum followed by a decrease in the rate u pon the addition of more calcium chloride. The non-linear dependence o f the proton acceptor concentration against the concentration of calci um chloride is explained in terms of the structure breaking of hydroge n bonds, increasing the proton transfer rate initially, and the deplet ion of free water molecules due to hydration leading to a slowing down of the proton transfer rate.