During production of butyl alcohols by the oxo process a head fraction, which is at present burned, is formed. The yield of the head fraction is relatively high; moreover, it contains about 60% of isobutyl alcohol, and therefore the problem of separation of the latter is of considerable importance. In addition to isobutyl alcohol, this fraction contains the following (mass %): isobutyraldehyde 2, dibutyl ether 6, n-butyl formate 4, isobutyl formate 11, unsaturated ethers 5. Of course, some fluctuations of composition are possible, depending on the synthesis conditions. The individual fractions were analyzed by the GLC method with the aid of the LKhM-8MD chromatograph with a katharometer detector. The results of analysis by the TBP distillation method showed that 60% of the total amount of isobutyl alcohol is concentrated in the fraction boiling in the range 96-108 degree ; its content in that fraction is about 80%. Therefore pure isobutyl alcohol cannot be obtained even with the use of an efficient fractionating column.