Use of esterified silica for separation of ethanol from water

Claim 1

A process for separating ethanol from a feed mixture comprising ethanol and water which process comprises contacting at adsorption conditions said mixture with an adsorbent consisting essentially of esterified silica which process comprises the steps of: (a) maintaining net fluid flow through a column of said adsorbent in a single direction, which column contains at least three zones having separate operational functions occurring therein and being serially interconnected with the terminal zones of said column connected to provide a continuous connection of said zones; (b) maintaining an adsorption zone in said column, said zone defined by the adsorbent located between a feed inlet stream at an upstream boundary of said zone and a raffinate outlet stream at a downstream boundary of said zone; (c) maintaining a purification zone immediately upstream from said adsorption zone, said purification zone defined by the adsorbent located between an extract outlet stream at an upstream boundary of said purification zone and said feed inlet stream at a downstream boundary of said purification zone; (d) maintaining a desorption zone immediately upstream from said purification zone, said desorption zone defined by the adsorbent located between a desorbent inlet stream at an upstream boundary of said zone and said extract outlet stream at a downstream boundary of said zone; (e) passing said feed stream into said adsorption zone at adsorption conditions to effect the selective adsorption of said ethanol by said adsorbent in said adsorption zone and withdrawing a raffinate outlet stream from said adsorption zone; (f) passing a desorbent material into said desorption zone at desorption conditions to effect the displacement of said ethanol from the adsorbent in said desorption zone; (g) withdrawing an extract stream comprising said ethanol and desorbent material from said desorption zone; and (h) periodically advancing through said column of adsorbent in a downstream direction with respect to fluid flow in said adsorption zone the feed inlet stream, raffinate outlet stream, desorbent inlet stream, and extract outlet stream to effect the shifting of zones through said adsorbent and the production of extract outlet and raffinate outlet streams.