Patent GB-738654-A (GB)
Title: Improvements in or relating to the recovery of aldehydes and alcohols from mixtures containing them
Inventor: MORRELL CHARLES EUGENE
IPC: C07C45/83
Filed: 1952-05-09
Abstract: Close-boiling aldehydes and alcohols are separated from a mixture obtained from the Oxo process by subjecting said mixture to simultaneous hydrolysis and extractive distillation in a tower, using as an extractive solvent a dilute aqueous acidic solution containing 5-70 per cent (preferably at least 20 per cent) of a water-soluble compound having an aromatic nucleus and one or more of the radicals:-sulpho, quaternary ammonium, sulphate ester, or phosphonate ester, said extractive solvent having a pH less than 7, preferably 1-5, and being present during said hydrolysis and extractive distillation in amounts ranging from 25-99 mol. per cent, the aldehydes being recovered from said tower as an overhead stream substantially free of alcohols, and alcohols being recovered, substantially free of aldehydes, from a lower portion of said tower. Water-soluble compounds specified are the sulphonic acids of benzene, toluene, xylene, cymene, naphthalene, dimethylaniline, naphthol, naphthylamine, nitrobenzene, and anthraquinone, and also pyridinium chlorides and sulphates and trimethyl phenyl ammonium hydroxide. Non-aqueous solvents such as alcohols, glycerol, dioxane, and ethylene glycol may be added.  Acidic substances such as hydrochloric, sulphuric, acetic, phosphoric, trichloracetic, and chloracetic acids and ammonium chloride may be used to adjust the pH. Examples describe the use of xylene and cymene sulphonic acid sodium salts in a conventional type of apparatus.  Specifications 647,927 and 655,698, [both in Group III], are referred to.ALSO:Close-boiling aldehydes and alcohols are separated from a mixture obtained from the oxo process by subjecting said mixture to simultaneous hydrolysis and extractive distillation in a tower, using as an extractive solvent a dilute aqueous acidic solution containing 5-70 per cent (preferably at least 20 per cent) of a water-soluble compound having an aromatic nucleus and one or more of the radicals: sulpho, quaternary ammonium, sulphate ester, or phosphonate ester, said extractive solvent having a pH less than 7, preferably 1-5, and being present during said hydrolysis and extractive distillation in amounts ranging from 25-99 mol. per cent, the aldehydes being recovered from said tower as an overhead stream substantially free of alcohols, and alcohols being recovered, substantially free of aldehydes, from a lower portion of said tower.  Water-soluble compounds specified are the sulphonic acids of benzene, toluene, xylene, cymene, naphthalene, dimethylaniline, naphthol, naphthylamine, nitrobenzene, and anthraquinone, and also pyridinium chlorides and sulphates and trimethyl phenyl ammonium hydroxide. Non-aqueous solvents such as alcohols, glycerol, dioxane, and ethylene glycol may be added. Acidic substances such as hydrochloric, sulphuric, acetic, phosphoric, trichloracetic, and chloracetic acids and ammonium chloride may be used to adjust the pH.  Examples describe the use of xylene and cymene sulphonic acid sodium salts in a conventional type of apparatus.  Specifications 647,927 and 655,698 are referred to.