Patent ID: 6180820
Filing Date: 2001-01-30
Classification: C07C

Abstract:
A process for producing n-butyl acrylate (BuAcA) comprising:(a) esterifying acrylic acid (HAcA) with n-butanol (BuOH) in a reaction zone from which an overhead vapor mixture is withdrawn, said vapor mixture containing BuAcA, BuOH, water and light ends components, said light ends components having boiling points near or somewhat lower than that of BuAcA,(b) condensing said vapor mixture to form an organic phase containing BuAcA, BuOH, light ends, and an aqueous phase containing predominantly water and BuOH,(c) feeding said organic phase to a finishing fractionation zone,(d) withdrawing BuAcA having a high degree of purity from said finishing zone,(e) withdrawing and condensing the overhead vapors from said finishing zone comprising a major portion of the total of BuAcA and BuOH present and minor portions of water and light ends,(f) recycling a major portion of said overhead condensate of the finishing zone to the reaction zone,(g) feeding a minor portion of said overhead condensate of the finishing zone together with a stream of makeup water, to a purge recovery fractionation zone,(h) condensing the overhead vapors of said purge recovery zone comprising significant amounts of BuOH, BuAcA, water and light ends to form an organic phase containing BuOH, BuAcA, and lights ends and an aqueous phase containing some BuOH, BuAcA and light ends,(i) recycling a portion of said organic phase of the overhead condensate from the purge recovery zone back to said purge recovery zone as reflux,(j) discarding the remainder of said organic phase,(k) recycling at least a portion of said aqueous phase of the overhead condensate of the purge recovery zone as feed to the purge recovery zone, with any remainder being discarded, wherein,the total amount of water in said recycled portion of the aqueous phase of the overhead condensate of the purge recovery zone and said makeup stream of water having the effect of increasing the formation of low boiling azeotropes with the components of light ends entering the purge recovery zone.