Aluminum alkyls, transalkylation with olefins

The solvent is 28 CC-olefins recycled from the fractionation section. Effluent from the reactors includes product a-olefins, unreacted ethylene, aluminum alkyls of the same carbon number distribution as the product olefins, and polymer. The effluent is flashed to remove ethylene, filtered to remove polyethylene, and treated to reduce the aluminum alkyls in the stream. In the original plant operation, these aluminum alkyls were not removed, resulting in the formation of paraffins (- 1.4%) when the reactor effluent was treated with caustic to kill the catalyst. In the new plant, however, it is likely that these aluminum alkyls are transalkylated with ethylene by adding a catalyst such as 60 ppm of a nickel compound, eg, nickel octanoate (6). The new plant contains a caustic wash section and the product olefins still contain some paraffins ( 0.5%). After treatment with caustic, cmde olefins are sent to a water wash to remove sodium and aluminum salts. 

Afterward the new aluminum alkyl is transalkylated with a C,2-Cl8 n-a-olefin mixture ... 

Karge and Ladebeck (90) studied the alkylation of benzene with olefins over aluminum-deficient, beryllium exchanged mordenite and found a considerable extension of the lifetime of the catalyst, as compared to H-mordenite. The authors were able to carry out quite efficiently the alkylation reaction as well as the transalkylation of ethylbenzene at relatively low temperatures. 

Both of these facts do explain the nickel effect. The first finding is the basis for the syntheses of Wilke s nickel(0)-olefin complexes (1 and 2) [Eq. (3)] 10), while the second reflects the fact that 1, 2, and (C2H4)3Ni(0) (3), which is obtained from 1 and ethylene 11, 12), are highly active catalysts for the transalkylation of aluminum alkyls with olefins as, for example in Eq. (4) 11, 13). 

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