Patent GB-335994-A (GB)
Title: Manufacture of new derivatives of cellulose
IPC: C08B13/02
Filed: 1929-03-25
Abstract: 335,994. Lilienfeld, L. March 25, 1929. Cellulose xanthates; cellulose ethers.-Technically valuable cellulose compounds are obtained by xanthating oxyalkyl derivatives of cellulose obtained by (a) acting on cellulose with an oxyalkylating agent in the presence of a substance having an alkaline reaction, e.g. caustic alkali, or (b) oxyalkylating alkali cellulose. Thus alkali cellulose may be treated with a halohydrin and the reaction product, with or without being washed or isolated, is subjected to the action of carbon bisulphide with or without additional alkali. Alternatively, alkali cellulose may be treated with a halohydrin and carbon bisulphide simultaneously or consecutively; where carbon bisulphide precedes the halohydrin the interval between the additions must be so short as to prevent conversion of the alkali cellulose into xanthate. Again, a paste or suspension of the reaction mass from alkali cellulose and halohydrin in caustic alkali may be treated with carbon bisulphide. Examples are given involving the treatment of alkali cellulose, prepared from wood pulp or linters by the. use of 10 per cent caustic soda, and matured or not, with a-monochlorhydrin or ethylenechlorhydrin ; the reaction mass, with or without standing and with or without washing, being further treated with caustic soda and carbon bisulphide. Other examples describe simultaneous treatment with the halohydrin and carbon bisulphide. In further examples, the reaction mass from the alkali cellulose and halohydrin is treated with 8 per cent caustic soda, allowed to stand, filtered, the oxyalkyl ether of cellulose is precipitated with 15 per cent sulphuric acid, washed, and dissolved in caustic soda, after which carbon bisulphide is added and the solution shaken. The final products may be isolated from the reaction masses or solutions, optionally after neutralizing with a weak acid, e.g., acetic, by precipitation by means of methyl or ethyl alcohols, salts of aluminium, ammonium chloride or sulphate, sodium chloride or sulphite or bisulphate, carbon or sulphur dioxide, sulphuric or hydrochloric acid, etc.; or by dialysis. The products are readily soluble in alkali and water and with acids yield coagulates or precipitates insoluble in water. Heavy metal salts, e.g. of zinc or copper, form corresponding salts. The products may be worked up as described in Specification 335,993. Other halohydrins include propylene-, mannite-, pinacone, erythrite-, pentaerythrite-, dulcitan, trimethylene-, glycol, divinylethyleneglycol-, phenyl-propanol-, naphthyl-propanol-, and 4-methoxynaphthyl-propanolchlorhydrins; also epichlorhydrn. Bromo- or iodohydrins may be employed. Dihalohydrins may also be employed, but where such tend to form insoluble compounds with alkali cellulose, they should be mixed with sufficient monohalohydrins as will produce soluble compounds with caustic alkali and carbon bisulphide. Catalysts, e.g. salts of copper, nickel, silver, zinc, iron, &c. may be added to the alkali cellulose or the reaction mixture. Instead of caustic soda, other alkalies, e.g. caustic potash, or sulphonium hydroxides, e.g. trimethylsulphonium hydroxide, may be employed. Near conversion products of cellulose., e.g. cellulose hydrate, hydrocellulose, or oxycellulose, may also be employed. Specification 231,807 is referred to.