This report covers research into the kinetics of the liquid phase reaction between chlorine and basic hydrogen peroxide (BHP) to produce singlet delta oxygen. The accepted mechanism for this reaction is given in three steps. The second step involves only a proton transfer and is expected to be much faster than the other two steps. The focus of this research was to measure (reaction rate constants) and k(3). Gas absorption measurements of chlorine in BHP in a laminar liquid jet absorber were carried out over the temperature range 1.8 to 8.9 C to determine k(1). The experimental data, obtained in the second-order kinetic regime, were interpreted using the penetration theory model. The k(1) measured is significantly lower than that estimated from previous work. Gas absorption measurements in a stirred cell absorber determined k(3). However, since this third step in the mechanism appears to have such fast kinetics, only a lower bound was determined fore this rate constant. At 0 C, the data indicate that k(3)> 500 l/s. Liquid phase reaction between chlorine and basic hydrogen peroxide, Laminar liquid jet absorber, Singlet delta oxygen, Reaction rates. Physical chemistry. (JG).

The reaction of chlorine with alkaline hydrogen peroxide solutions, approximately 2.5M in 02H-, has been examined in an unagitated batch reactor at 10 degrees C. Initial chlorine partial pressures of up to 450 torr and reaction times of one, three and six minutes were investigated. The results are in qualitative agreement with the theory for absorption with an instantaneous reaction, in which the rate of reaction becomes controlled by liquid phase mass transfer after an initial, rapid reaction depletes the interfacial region of 02H- reactant. The effective anion diffusivity was on the order of 7 times 10( -4) sg. cm per sec, a value much larger than typical liquid diffusivities. The rate of reaction declined faster than the time ( -1/2) dependence predicted by the theory for absorption with an instantaneous reaction. In one minute's time, complete conversion of all added chlorine to chloride ion was achieved until 4.7 time 10( --4) moles of chlorine per sq. cm of interfacial area have reacted. Subsequent reaction was almost independent of initial chlorine partial pressure. The amount of chlorine reaction was not sensitive to the rate of oxygen produced by hydrogen peroxide disproportionation. The rate of disproportionation was seen to depend in a complicated manner on the composition of the alkaline solutions.