Patent ID: 6049020
Filing Date: 2000-04-11
Classification: C07C

Abstract:
A process for the production of a pure tertiary olefin and/or a tertiary alkyl ether from a hydrocarbon cut containing at least one etherifiable tertiary olefin, the process comprising:a) a step for forming at least one tertiary alkyl ether by bringing at least one hydrocarbon cut containing at least one etherifiable tertiary olefin into contact with at least one alcohol in a reaction zone (R1) containing an etherification catalyst;b) a step for separating the major portion of the product from step a) into an organic fraction (O1) which is depleted in tertiary alkyl ether and an organic fraction (E1) which is enriched in the tertiary alkyl ether formed during step a);c) a step for decomposing at least a portion of the tertiary alkyl ether contained in the organic fraction (E1) from step b), in a reaction zone (R2) containing a catalyst for decomposing said ether, into a product (P1) containing at least one alcohol and at least one tertiary olefin;d) a step for fractionating at least a portion of product (P1) in a fractionation zone (C1) to obtain a fraction (A) containing the major portion of the tertiary olefin and optionally a minor fraction of the alcohol and optionally light compounds, initially contained in said portion of product (P1), and a fraction (B) containing the major portion of the alcohol formed in step c) and optionally ether which has not decomposed in step c);e) a step for purifying at least a portion of fraction (A) in which said portion is sent to a water washing extraction zone (L1) from which an aqueous fraction (C) is obtained containing the major portion of the alcohol initially present in said portion and a fraction (D) is obtained containing the major portion of the tertiary olefin initially present in said portion, said fraction (D) containing said tertiary olefin, water, optionally light compounds and being substantially free of alcohol;said process being characterized in that it comprises a step f) in which at least a portion of fraction (D) is sent to a separation zone (Co) from which an aqueous liquid fraction (Le) and an organic liquid fraction (Ohp1) containing the major portion of the tertiary olefin initially present in said portion of fraction (D) are recovered, said fraction (Ohp1) containing said tertiary olefin, a small quantity of water and optionally light compounds.