NOVELTY - Conversion (P1) of a hydrocarbon feedstock into alcohol involves synthesizing the hydrocarbon feedstock to produce a mixture of carbon oxide and hydrogen (synthesis gas); synthesizing carbon monoxide and the hydrogen to produce methanol; etherifying the methanol to produce dimethyl ether; carbonylating the dimethyl ether with carbon monoxide in the presence of an iridium carbonylation catalyst to produce methyl ethanoate; hydrogenating the methyl ethanoate with hydrogen to produce methanol and ethanol; recycling the methanol; and recovering the ethanol.    USE - For the conversion of a hydrocarbon feedstock into alcohol (preferably methanol to ethanol) (claimed). The hydrocarbon feedstock is preferably a carbonaceous material, e.g. biomass, plastic, naphtha, refinery bottoms, crude syngas (from underground coal gasification or biomass gasification), smelter off gas, municipal waste, coal bed methane, coal, and/or natural gas.    ADVANTAGE - The process provides carbonaceous feedstock, with improved carbon efficiency, higher selectivity and particularly, with a more efficient conversion to ethanol. In the process, both the hydrogen fed to the hydrogenation unit and the carbon monoxide fed to the carbonylation unit, in the presence of an iridium base catalyst, are obtained from synthesis gas (hydrogen) separation stage. The catalyst system used in the carbonylation process is beneficial at low partial pressures of carbon monoxide. The catalyst system provides an increased rate of reaction over catalyst systems without the promoters. This allows for an increased rate of reaction under conditions when the carbon monoxide partial pressure is relatively low, for example due to a low total pressure in the carbonylation unit or due to high vapor pressure of components of the liquid reaction composition, e.g. at high methyl ethanoate and/or dimethyl ether concentration in the liquid reaction composition or due to a high concentration of inert gases in the carbonylation unit. The catalyst system has advantages of increasing rate of carbonylation when the rate of reaction is reduced by carbon monoxide in solution in the liquid reaction composition resulting from mass transfer limitations, for example due to poor agitation.    DETAILED DESCRIPTION - Conversion (P1) of a hydrocarbon feedstock into alcohol, where the hydrocarbons are first converted into synthesis gas, which is converted into alcohol involving: introducing the hydrocarbon feedstock into a synthesis gas unit to produce a mixture of carbon oxide and hydrogen (synthesis gas); introducing carbon monoxide and the hydrogen into a methanol synthesis unit to produce methanol; introducing the methanol into an etherification unit to produce dimethyl ether; introducing the dimethyl ether together with carbon monoxide into a carbonylation unit in the presence of an iridium carbonylation catalyst to produce methyl ethanoate; introducing the methyl ethanoate together with hydrogen into a hydrogenation unit to produce methanol and ethanol; recycling at least part of the methanol into the etherification unit; and recovering the ethanol. An INDEPENDENT CLAIM is included for conversion of methanol to ethanol involves introducing methanol into an etherification unit to produce dimethyl ether; introducing the dimethyl ether together with carbon monoxide into a carbonylation unit in the presence of an iridium carbonylation catalyst, to produce methyl ethanoate; introducing the methyl ethanoate together with hydrogen into a hydrogenation unit, to produce methanol and ethanol; recycling at least part of the methanol into the etherification unit; and recovering the ethanol.