| 摘要 |
A process of reacting a liquid reactant with a gaseous reactant in the presence of a catalyst to produce a desired product, the rate of reaction being dependent on the concentration of catalyst present, comprises passing the gaseous reactant through a series of two zones each containing catalyst, mixing a portion of the liquid reactant with the gaseous reactant in the first zone, passing unreacted gaseous reactant from the first zone and mixing it with another portion of the liquid reactant in the second zone, the first zone containing insufficient catalyst to enable the reaction to go to completion and the second zone containing sufficient catalyst to enable substantially all the gaseous reactant present therein to be converted to the desired product, and recovering said product. The series of two zones may be two zones of a packed column, a series of separate reactors or separate groups of reactors arranged in cascade form. The two zones may be adjacent or separate. The catalyst may be placed in the zones before the reactants are fed in or may be introduced in admixture with the liquid reactant either by introducing portions of the liquid reactant containing different catalyst concentrations into the two zones or by feeding all the catalyst with the liquid reactant to the second zone and feeding liquid reactant not containing catalyst to the first zone, catalyst passing with the liquid phase from the second to the first zone and being diluted therein. The product may be recovered from the effluent from the first zone. The process is illustrated by the reaction of ketene and diethoxymethane in the presence of a BF3 catalyst to give ethyl 3-ethoxypropionate. Specification 828,371 is referred to.ALSO:A process of reacting a liquid reactant with a gaseous reactant in the presence of a catalyst to produce a desired product, the rate of reaction being dependent on the concentration of catalyst present, comprises passing the gaseous reactant through a series of two zones each containing catalyst, mixing a portion of the liquid reactant with the gaseous reactant in the first zone, passing unreacted gaseous reactant from the first zone and mixing it with another portion of the liquid reactant in the second zone, the first zone containing insufficient catalyst to enable the reaction to go to completion and the second zone containing sufficient catalyst to enable substantially all the gaseous reactant present therein to be converted to the desired product, and recovering said product. The series of two zones may be two zones of a packed column, a series of separate reactors or separate groups of reactors arranged in cascade form. The two zones may be adjacent or separate. The catalyst may be placed in the zones before the reactants are fed in or may be introduced in admixture with the liquid reactant, either by introducing portions of the liquid reactant containing different catalyst concentrations into the two zones or by feeding all the catalyst with the liquid reactant to the second zone and feeding liquid reactant not containing catalyst to the first zone, catalyst passing with the liquid phase from the second to the first zone and being diluted therein. The product may be recovered from the effluent from the first zone. The process is illustrated by the reaction of ketene and diethoxymethane in the presence of a BF3 catalyst to give ethyl 3-ethoxy-propionate. Specification 828,371 is referred to. |
