Patent GB-964280-A (GB)
Title: Improvements in or relating to processes for clarifying and stabilizing vegetable beverages containing tannin
IPC: C12C7/24
Filed: 1961-11-10
Abstract: N-polyvinyl polylactams are obtained by treating either N-vinyl-a -pyrrolidone according to the method disclosed in U.S.A. Specification 2,938,017 or analogous N-vinyl lactams represented by the general formula: <FORM:0964280/C3/1> wherein n represents 3, 4 or 5 and R represents hydrogen, methyl or ethyl, particularly N-vinyl-5-methyl pyrrolidone, N-vinyl caprolactam and N-vinyl piperidone, in a manner analogous to that in which the N-vinyl pyrrolidone is treated; this involves heating the N-vinyl lactam to a temperature of from 40 DEG C. to 200 DEG C. in the presence of a small amount of an alkali polymerization catalyst, such as sodium or potassium hydroxide and sodium methylate. According to an example, 200 g. N-vinyl pyrrolidone and 2 g. sodium hydroxide flakes were heated in a distilling flask at 100 mm. under total reflux for about 3 hours. At this time the temperature rose from 145 DEG C. to 190 DEG C. and the refluxing monomer was converted to a white solid.  After cooling, the polymer was slurried with water to wash out caustic and unconverted monomer, filtered, and dried at 50-60 DEG C. in vacuo. The polyvinyl polypyrrolidone produced had a melting point of at least about 300 DEG C. and was insoluble in common solvents (specified).  The N-polyvinyl polylactams may be employed in the form of an active coating on an inert carrier such as silica gel, alumina, talc or diatomaceous earth, or as an aqueous slurry or suspension, for removing tannin from tannin-containing aqueous liquids such as beer. Specification 854,455 and U.S.A. Specification 2,317,804 also are referred to.ALSO:Tannin is removed from tannin-containing liquids such as wort, beers, ales, brandies, whiskies, wines, fruit juices and pharmaceutical liquors, by absorbing the tannins with an effective quantity of certain N-polyvinyl polylactams characterized by their high melting points and insolubility in common solvents. The N-polyvinyl polylactams are obtained by treating either N-vinyl-a -pyrrolidone according to the method disclosed in U.S.A. Specification 2,938,017 or analogous N-vinyl lactams represented by the general formula: <FORM:0964280/C6-C7/1> wherein n represents 3, 4 or 5 and R represents hydrogen, methyl or ethyl, particularly N-vinyl-5-methyl pyrrolidone, N-vinyl caprolactam and N-vinyl piperidone, in a manner analogous to that in which the N-vinyl-a -pyrrolidone is treated; this involves heating the N-vinyl lactam to a temperature of from 40-200  DEG C. in the presence of a small amount of an alkali polymerization catalyst.  The N-polyvinyl polylactam may be employed in powder, paste or sheet form, as an active coating on an inert carrier such as silica gel, alumina, talc or diatomaceous earth, or as an aqueous slurry or emulsion.  The following may be utilized in co-related proportions to the amount of the N-polyvinyl polylactam:  papain proteolytic enzyme chill proof material, polyvinyl pyrrolidone, alginic acid (foam stabilizer), and potassium metabisulphite, sodium dithionite and other materials for imparting sulphur dioxide. Examples are directed to the removal of anthocyanogens from ale in storage, from brewer's wort in the kettle and from port wine employing either the polyvinyl polypyrrolidone or polyvinyl polycaprolactam produced as specified above; in control experiments the comparative effect of hexamethylenediamine adipate (Nylon 66) is studied. Specification 854,455 also is referred to.