Teijin Limited

Kazumi Iwata

Takeo Shima

Michiyuki Tokashiki

Takeyoshi Yamada

A gas-permeable laminate for separating a specific gas from a gaseous mixture comprising a gas-permeable membrane having excellent selectivity for the specified gas and a porous support supporting said membrane, said gas-permeable membrane being a multilayer laminated membrane comprising at least a first and a second ultrathin membrane having excellent selectivity for the specified gas and a third ultrathin membrane of a different material from the materials of the first and second ultrathin membranes and located between the first and second ultrathin membranes, the material of the third ultrathin membrane having a higher permeation coefficient with respect to the specified gas than the materials of the first and second ultrathin membranes.

Gas-permeable laminate

In the process for preparing alkenylbenzene by the catalytic reaction of alkylbenzenes and 1,3-butadiene in the presence of an alkali metal catalyst, the improvement which comprises effecting the preliminary contact of the freshly fed alkylbenzene with the reaction product of said catalyst reaction and thereafter catalytically reacting said alkylbenzene with said 1,3-butadiene.

Process for preparing alkenylbenzenes

In the method wherein an alkenylation reaction product liquid obtained by the alkenylation reaction of an alkylbenzene and a C.sub.4 - C.sub.5 conjugated diene in the presence of alkali metal catalysts and containing unreacted alkylbenzene, alkali metal catalysts and organo-alkalimetal compounds is conveyed to a distillation zone at which said alkenylation reaction product liquid is separated by distillation to recover an alkenylbenzene-containing fraction and an unreacted alkylbenzene-containing fraction, the improvement which comprises adjusting the total of the concentrations of said alkali metal catalysts and organo-alkalimetal compounds in said alkenylation reaction product liquid introduced to the distillation zone so as to be 0.09 - 15 milligram atoms per kilogram of said product liquid, calculated as alkalimetal atoms, and thereafter conducting the distillation of said product liquid under conditions of non-addition of alcohols.

Method of separating and recovering alkenylbenzenes and unreacted

In the process for preparing monoalkenylbenzenes by reacting an alkylbenzene and a C.sub.4 - C.sub.5 conjugated diene in the presence of an alkali metal catalyst while passing the reactants progressively through a series of successive reaction zones substantially isolated from each other under non-back-flow conditions, the reaction being carried out at this time while feeding said alkylbenzene and alkali metal catalyst to the first reaction zone and the conjugated diene separately to at least two of said zones, and thereafter withdrawing the reaction product from the final reaction zone of said series; the improvement which comprises (1) reacting the reactants including the alkylbenzene, C.sub.4 - C.sub.5 conjugated diene and alkali metal catalyst under boiling conditions in at least one of the reaction zone selected from the second and subsequent reaction zones; and (2) recovering the evaporated product from said reaction zone or zones as a liquid and recycling same to a reaction zone preceding that at which the product was evaporated.

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Iwakuni, Japan

Kazumi Iwata