NOVELTY - Producing ethanol comprises (a) reacting carbon monoxide with at least one reactant (16) in a first reactor containing a reaction medium to produce a reaction solution comprising acetic acid (20), (b) purifying the reaction solution to yield an acetic acid product stream and at least one derivative stream (22), (c) introducing at least a portion of the acetic acid product stream and at least a portion of the derivative stream into a second reactor in the presence of a second catalyst to form a crude ethanol product and (d) recovering ethanol from the crude ethanol product.    USE - The process is useful for producing ethanol (claimed) from petrochemical feed stocks such as oil, natural gas or coal, from feed stock intermediates such as syngas or from starchy materials or cellulose materials such as corn or sugar cane, where ethanol is useful: as fuels for motor vehicles such as automobiles, boats and small piston engine aircraft; as a solvent for toiletry and cosmetic preparations, detergents, disinfectants, coatings, inks and pharmaceuticals; as a processing solvent in manufacturing processes for medicinal products, food preparations, dyes, photochemicals and latex processing; as chemical feedstock to make other chemicals such as vinegar, ethyl acrylate, ethyl acetate, ethylene, glycol ethers, ethylamines, ethyl benzene, aldehydes, butadiene, and higher alcohols, especially butanol; and in other applications including pharmaceutical products, cleansers, sanitizers, hydrogenation transport or consumption.    ADVANTAGE - The ethanol can be economically and energy-efficiently produced with high purity and increased yield and without waste generation.    DETAILED DESCRIPTION - Producing ethanol comprises: either (a) reacting carbon monoxide with at least one reactant (16) in a first reactor containing a reaction medium to produce a reaction solution comprising acetic acid (20), where the reactant is methanol, methyl acetate, methyl formate and/or dimethyl ether and the reaction medium comprises water, acetic acid, methyl iodide and a first catalyst, (b) purifying the reaction solution to yield an acetic acid product stream and at least one derivative stream (22), (c) introducing at least a portion of the acetic acid product stream and at least a portion of the derivative stream into a second reactor in the presence of a second catalyst to form a crude ethanol product, which is substantially free of methanol, methyl acetate, methyl formate and/or dimethyl ether and (d) recovering ethanol from the crude ethanol product; or the step (a), (b) and (c) as above per se, (e1) separating the crude ethanol product into an ethanol product and one or more recycle streams and (f1) introducing the derivative stream into at least one of the recycle streams.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of an integrated system for producing ethanol.    Hydrogenation system (14)    Reactant (16)    Carbon monoxide feed (18)    Acetic acid (20)    Derivative stream. (22)