Patent GB-732116-A (GB)
Title: Improvements in or relating to the treatment of ligneous liquors
Inventor: EHRENSPERGER HANS
IPC: C08H5/02
Filed: 1952-03-17
Abstract: Nitrogen-containing addition products are obtained by treating a ligneous liquor with a quaternary ammonium compound and then separating the resulting precipitated addition product from the mother liquor.  The process may be operated for the recovery of lignin constituents from ligneous liquors by subjecting the liquor to the action of a quaternary ammonium compound to precipitate an addition product consisting of lignin constituents combined with the quaternary ammonium material, separating the addition product from the mother liquor and then decomposing it to isolate the lignin constituents.  The invention also comprises as a new product the addition product of lignin sulphonic acid and a quaternary ammonium compound.  The lignin constituents may be the waste lignins from acid sulphite and alkaline treatment of wood or other plant material in the production of cellulose pulp. Specified quaternary ammonium compounds are alkyl-trimethyl-ammonium chlorides, cetyl pyridinium bromide, tetradecyl pyridinium bromide, dimethyl phenyl benzyl ammonium chloride, stearamido-methyl pyridinium chloride, cetyl trimethyl ammonium bromide, lauryl trimethyl ammonium bromide, tris(hydroxyethyl)benzyl ammonium chloride, benzyl pyridinium chloride, triethyl benzyl ammonium chloride, tris(hydroxyethyl)propyl ammonium chloride, tris(hydroxyethyl)ethyl ammonium ethylo sulphate and di-alkyl-dimethyl ammonium chlorides.  The addition products may be separated into the ligneous and quaternary ammonium constituents by various procedures, e.g. by reacting with a strong mineral acid such as hydrochloric, sulphuric or phosphoric acid and in the case where the separated ligneous liquor contains lignin sulphonic acid it may be dissolved in alkalies to form a solution of the alkali metal salt of lignin sulphonic acid from which the lignin sulphonic acid may be precitated by acidifying. The addition products may also be decomposed by treating with strong caustic alkali at about 100 DEG C.  The quaternary ammonium component may also be separated from the addition compound by adding an organic chloride or hydrocarbon such as carbon tetrachloride or kerosene, or an alcohol or other solvent for the quaternary ammonium compound.  The sugar-containing mother liquors remaining after removal of the addition products may be used in the manufacture of alcohol or furfural or may be treated by ion exchange to recover the sugars in a more purified form.  In examples (1) freshly blown sulphite liquor is neutralized with calcium carbonate whilst air is simultaneously blown through the liquor to drive off excess sulphur dioxide.  The pH is then adjusted to 5.8 by adding calcium hydroxide and after cooling to room temperature cetyl dimethyl benzyl ammonium chloride is added to the liquor until all precipitation ceases and the liquor is then heated to above 120 DEG F. so as to cause the precipitated particles to fuse and deposit as a plastic mass from which the mother liquor is decanted; (2) freshly blown pit liquor is aerated to remove excess sulphur dioxide and the pH is then adjusted to 7.4 by adding caustic alkali the liquor being then treated as in (1) to precitate the addition product; (3) freshly blown pit liquor with a pH of 2.3 is treated with the same quaternary ammonium reagent and in the same manner as in (1).  The addition products may be used to replace, in whole or in part, the phenols, e.g. resorcinol, used in the manufacture of phenol-based synthetic resins and may also be used as raw material for polymerization and condensation reactions.