Abstract: The present invention provides an improved sulfuric acid catalyzed alkylation process wherein the sulfur content from one or more streams in the alkylation process is recovered by an extraction agent. The extraction agent of the invention comprises ammonia or ammonium hydroxide. Advantageously, the recovered sulfur content is converted to sulfuric acid, such as in a spent acid regeneration (SAR) plant, and recycled to replenish decomposed catalyst in the alkylation process.

Abstract: Disclosed are various embodiments for alkylating olefins and isoparaffins in the presence of an acid to reduce and/or control acid consumption or maximize and/or control the octane number of the produced alkylate product. One embodiment includes alkylation by controlling the C.sub.3 /C.sub.5 olefin ratio to reduce acid consumption. Another embodiment includes alkylation of C.sub.3 and C.sub.5 olefins in separate alkylation zones to maximize alkylate octane number. Even another embodiment includes propylene alkylation followed by C.sub.4 and/or C.sub.5 olefin alkylation, with the spent propylene acid used in the C.sub.4 and/or C.sub.5 olefin alkylation. Still another embodiment includes alkylation of C.sub.3, C.sub.4 and C.sub.5 olefins in separate alkylation zones, with the spent propylene acid used in the C.sub.4 alkylation, and the spent butylene acid used in the C.sub.5 alkylation. Yet another embodiment includes alkylation by controlling the C.sub.3 /C.sub.