GB403439A - Improvements relating to the recovery of the principal constituents of pyroligneous acid - Google Patents

Abstract

The principal volatile liquid organic constituents of pyroligneous acid are separated by adding a phenol or mixture of phenols so as to form molecular compounds with these substances, separating the mixed compounds from the aqueous medium, and applying successively increasing temperatures so as to decompose the molecular compounds successively. Alternatively the vapour of the pyroligneous acid may be passed through a series of vessels containing a phenol or phenol mixture which are maintained at successively decreasing temperatures such that in each vessel only one molecular compound is formed, these being subsequently heated to higher temperatures to obtain the separate constituents. In the first method a mixture of m-and pcresols with xylenols is mixed with the pyroligneous acid at 45--50 DEG C., the water layer being rejected. The phenolic molecular compounds are then led to a series of columns maintained at 85 DEG , 95 DEG , 100 DEG and 145 DEG C. respectively in which acetone methyl alcohol, water, and acetic acid are distilled off separately. In the second process the vapour of pyroligneous acid is passed through a series of vessels containing the same phenolic mixture maintained respectively at 95--100 DEG C. to absorb acetic acid, 85--90 DEG C. to absorb methyl alcohol, and from room temperature to 40 DEG C. to absorb acetone. Each molecular compound is then separately heated as described above. Specifications 275,158, [Class 32, Distilling, &c.], and 390,185 are referred to. The Specification as open to inspection under Sect. 91 included also the treatment of aqueous solutions containing organic solvents with one or more organic substances of higher or lower boiling-point capable of forming molecular compounds insoluble in water, which compounds are decanted from the water and fractionally decomposed to obtain the volatile solvents separately. Volatile solvents mentioned are hydrocarbons alcohols, aldehydes, ketones, acids, and ethers. This p subject-matter does not appear in the Specification as accepted.