Patent ID: 6673977
Filing Date: 2004-01-06
Classification: C07C

Abstract:
A process for the alkylation of isobutane by olefinic hydrocarbons, comprising the steps of:contacting a first hydrocarbon charge rich in isobutane (3) with a second hydrocarbon charge rich in light olefins (2), under conditions that will provoke the alkylation of the isobutane by light olefins; treating the effluents that emanate from a reaction area in a fractionation column (6) in order to extract at least a first cut rich in alkylate (7), a second cut rich in normal butane (8), and a third cut rich in isobutane (9); and recycling said third cut rich in isobutane (9) at an entry of an alkylation reaction area; wherein said second cut rich in normal butane (8) has a content of compounds with 5 or more carbon atoms that is more than 0.5 wt %, and said second cut rich in normal butane (8) is purified (12) by distillation with one single cut point chosen between the boiling point of normal butane and the boiling point of iso-pentane so as to lower its content in compounds with 5 or more carbon atoms to a value that is less than or equal to 0.5 wt %, and wherein said second cut thus purified (14) is treated in an isomerization reactor (16) of the normal butane to isobutane, and said second cut thus purified and treated (21) is recycled at an entry of an alkylation effluent fractionation column (6).