| 摘要 |
<PICT:0637414/III/1> Alcohols are recovered from hydrolysed acid extracts, obtained by absorbing olefins in sulphuric acid and then hydrolysing the esters so formed by addition of water, by distilling the extract in the presence of a small amount of an added hydrocarbon oil which is non-volatile at the temperature of distillation. By this means the deposition of tarry and resinous polymers inside the still is prevented; for the polymers are dissolved or dispersed in the oil. A C4 hydrocarbon fraction containing 15-80 per cent butenes is mixed with sulphuric acid in agitator 1 which is maintained at 25-50 DEG C. by refrigeration coil 4. Unreacted butenes and other hydrocarbons are removed from the extract in settler 7, and it is then mixed with water in mixer 11. The mixture is passed at a slow rate through hydrolyser 12, and the hydrolysed extract withdrawn through line 13 is diluted with water from line 14 to an acid concentration of 45 per cent, and introduced into stripper 16 at about 75 DEG C. Steam is introduced into the base of the stripper and a non-volatile oil prepared from a naphthenic base crude, is supplied to the middle through line 19. Butyl alcohol is taken off at the head of the stripper, and a mixture of dilute acid and oil is withdrawn from the base. The mixture is passed to settler 22. After decantation from the oil, the acid is passed to reconcentrator 24 where it is heated by indirect heat exchange with diphenyl or a mixture of diphenyl and diphenyl oxide. The concentrated acid is then recycled to agitator 1. The oil is preferably added continuously to the stripper at a rate of 0.05 per cent of that of the hydrolysed extract; but it may also be added periodically. |
