| 摘要 |
PURPOSE: Provided is a multi-phase method for producing ethylbenzene by alkylation and alternative transalkylation over a molecular sieve catalyst for aromatic alkylation, followed by the liquid-phase alkylation of the polyalkylated aromatic components. CONSTITUTION: In the production of ethylbenzene and the separate transalkylation of polyethylbenzene, the method comprises: (a) providing a first alkylation reaction zone containing a molecular sieve aromatic alkylation catalyst; (b) supplying a feedstock containing benzene and ethylene to the first alkylation reaction zone; (c) operating the alkylation reaction zone at temperature and pressure conditions in which benzene is in the gaseous phase to cause gas-phase ethylation of the benzene in the presence of the molecular sieve catalyst to produce an alkylation product comprising a mixture of xylene, ethylbenzene and polyalkylated aromatics; (d) recovering the alkylation product from the reaction zone and supplying the product from the reaction zone to an intermediate recovery zone for the separation and recovery of ethylbenzene from the alkylation product and the separation and recovery of a polyalkylated aromatic component including diethylbenzene; (e) supplying at least a portion of the polyalkylated aromatic component including diethylbenzene in the polyalkylated component to a transalkylation zone containing a molecular sieve transalkylation catalyst; (f) supplying benzene to the transalkylation reaction zone; (g) operating the transalkylation reaction zone under temperature and pressure conditions to cause disproportionation of the polyalkylated aromatic fraction to produce a disproportionation product containing unreacted benzene and having a reduced diethylbenzene content and an enhanced ethylbenzene content; (h) supplying disproportionation product from the transalkylation reaction zone to a second alkylation reaction zone containing a molecular sieve aromatic alkylation catalyst; (i) supplying ethylene to the second alkylation zone and operating the second alkylation reaction zone at temperature and pressure conditions in which the unreacted benzene is maintained in the liquid phase to cause liquid phase ethylation of the benzene to produce an alkylation product containing xylene in a lower xylene concentration than the xylene concentration in the alkylation product from the first recited alkylation reaction zone; and (j) supplying the alkylation product form the second alkylation zone to the intermediate recovery zone. |
