A new preparative route to short-chain aliphatic alcohols has been developed where the products, optionally based upon syngas feedstock, are useful as octane boosters or may be used directly as basic chemical products. Within definite CO/MeOH and H-2/CO mole ratios by carbonylating methanol at 210 bar and 180 degrees C in the presence of polymer-supported rhodium catalysts and an iodide-containing promoter the principal product acids are the acetic, propionic, butyric, valeric and hexanoic. These fractions may be converted to corresponding esters by a transesterification reaction and finally to alcohols by hydrogenolysis.