Perspectives in gas—liquid reactions

Activity and Selectivity of Palladium Catalysts during the Liquid-Phase Hydrogenation of Phenol. Influence of Temperature and Pressure

“…However, carrying out the reaction in the liquid phase, in a slurry reactor, may present important advantages with respect to the gas phase, e.g., better temperature control due to the higher heat capacity of the liquids, thus increasing catalyst life and quality and uniformity of the reaction products (Sharma, 1983), characteristics of great importance for the increasing production of fine chemicals. Moreover, liquid-phase processes allows a better selectivity for similar conversion than do gas-phase processes (Koopman et al, 1980).…”

Absorption of carbonyl sulfide in aqueous alkaline solutions: new strategies

“…The strategy of using an emulsified nonvolatile second liquid phase to intensify the specific rate of absorption of a sparingly soluble gas in liquid where it reacts was originally suggested by Sharma (1983). The suggested role of the second liquid phase was probed by Mehra and Sharma (1985) for the absorption of propylene, but-l-ene, and isobutylene into emulsions of chlorobenzene in aqueous solutions of sulfuric acid.…”

“…The conditions given below should be satisfied: In the above regime, a considerable amount of solute gas is consumed in the diffusion film. So, the suggested mechanism of enhancement of specific rate of absorption will occur when the droplet size of the dispersed second liquid phase is smaller than the diffusion film thickness (Sharma, 1983). Mehra (1988) has presented an analytical solution, based on Danckwerts' surface renewal theory, of the unsteadystate differential species balance equations for both the continuous and microdispersed phases, with an assumption that the droplets are stationary, and there is no reaction within the emulsified organic phase, which is as follows: For the case when there is no reaction within the microphase, the condition for no depletion of B in the continuous phase, near the gas-liquid interface, is (Mehra, 1988) [B0] This condition was found to hold.…”

Behavior of highly dispersed platinum catalysts in liquid-phase hydrogenations

“…Nevertheless, derived from the fact of working simultaneously with three phases-a solid catalyst, liquid reactants and solvents, and gaseous hydrogen-several problems mainly of diffusional nature, arise (Kiperman, 1986; Odenbrand and Lundin, 1980), with the most important due to hydrogen access to the liquid phase (Koopman et al, 1980;Sharma, 1983; Acres and Bond, 1966). Studying these problems and limiting the working conditions in which their effects are negligible are essential before going any further.…”