Patent GB-400168-A (GB)
Title: Improvements in or relating to the treatment of carbohydrates
IPC: C13K1/02
Filed: 1932-03-08
Abstract: Acid celluloses are among the conversion products obtained by the hydrolysis of cellulose with salts of acid character, the material being impregnated with the solutions, which are first concentrated in contact therewith and then allowed to act thereon until the desired degree of hydrolysis is attained.  Suitable salts are bisulphates, or salts capable of developing an acid reaction in solution in water, such as cupric salts, for example, copper sulphate, or of nickel sulphate, aluminium sulphate, or zinc chloride.  Preferably the amount of solution used for the hydrolysis is less than four times the amount of the cellulose, a larger quantity of solution being added originally, if desired, in order to obtain a uniform distribution through the materials, which are then pressed to remove the excess liquor.  The concentration may be carried on to any suitable degree, if desired until a part of the salt is in the solid phase.  The concentration is preferably effected at temperatures below 100 DEG  C., and may be aided or brought about by blowing hot gases such as air, nitrogen, or carbon dioxide, through the materials.  The subsequent treatment with the concentrated solutions may take place at normal or elevated pressures, and at temperatures ranging from 30 to 100 DEG  C. according to the nature of the salt employed and the concentration of the solution.  The cellulosic materials are preferably employed in the state of fibres, small pieces, chips, or powder.  Suitable materials are wood chips, sawdust and the like, sulphite pulp, sulphate pulp, or mechanical wood pulp. According to one example, sulphite pulp is steeped in sodium bisulphate solution, the excess liquor drained off, and the mass pressed.  Concentration is effected in a vessel heated to 30 DEG  C. with the aid of carbon dioxide or nitrogen heated to 35 DEG  C.  The vessel is then closed, and the temperature maintained at 50 DEG  C. for 15 hours.  The chief products are dextrins, but acid celluloses may also be formed.  According to another example, the hydrolysis is carried out with a hydrated copper sulphate or an aluminium sulphate solution, the solution being concentrated to 50-60 per cent and allowed to act for 3-5 hours at 50 DEG  C. to give a product consisting chiefly of acid celluloses.  Specification 354,820, [Group VI], is referred to.ALSO:Dextrins are among the conversion products obtained by the hydrolysis of cellulose with salts of acid character, the material being impregnated with the solutions, which are first concentrated in contact therewith and then allowed to act thereon until the desired degree of hydrolysis is attained.  Suitable salts are bisulphates or salts capable of developing an acid reaction in solution in water, such as cupric salts, for example, copper sulphate, or nickel sulphate, aluminium sulphate, or zinc chloride. Preferably the amount of solution used for the hydrolysis is less than four times the amount of the cellulose, a larger quantity of solution being added originally, if desired, in order to obtain a uniform distribution through the materials, which are then pressed to remove the excess liquor.  The concentration may be carried on to any suitable degree, if desired until a part of the salt is in the solid phase.  The concentration is preferably effected at temperatures below 100 DEG  C. and may be aided or brought about by blowing hot gases such as air, nitrogen, or carbon dioxide, through the materials.  The subsequent treatment with the concentrated solutions may take place at normal or elevated pressures, and at temperatures ranging from 30-100 DEG  C. according to the nature of the salt employed and the concentration of the solution.  The cellulosic materials are preferably employed in the state of fibres, small pieces, chips, or powder.  Suitable materials are wood chips, sawdust and the like, sulphite pulp, sulphate pulp, or mechanical wood pulp. According to one example, sulphite pulp is steeped in sodium bisulphate solution, the excess liquor drained off, and the mass pressed.  Concentration is effected in a vessel heated to 30 DEG  C. with the aid of carbon dioxide or nitrogen heated to 35 DEG  C.  The vessel is then closed, and the temperature maintained at 50 DEG  C. for 15 hours.  The dextrins formed may be separated in any convenient manner from other hydrolysis products, for example, the dextrin may be obtained substantially free from acid celluloses by filtration of its aqueous solution, while sugars may be removed by washing the dextrin with aqueous alcohol.  Specification 354,820 is referred to.ALSO:Dextrins, sugars, and other conversion products including acid celluloses are obtained by the hydrolysis of cellulose with salts of acid character, the material being impregnated with the solutions, which are first concentrated in contact therewith and then allowed to act thereon until the desired degree of hydrolysis is attained.  Suitable salts are bisulphates, or salts capable of developing an acid reaction in solution in water, such as cupric salts, for example, copper sulphate, or of nickel sulphate, aluminium sulphate, or zinc chloride.  Preferably the amount of solution used for the hydrolysis is less than four times the amount of the cellulose, a larger quantity of solution being added originally, if desired, in order to obtain a uniform distribution through the materials, which are then pressed to remove the excess liquor.  The concentration may be carried on to any suitable degree, if desired, until a part of the salt is in the solid phase.  The concentration is preferably effected at temperatures below 100 DEG  C., and may be aided or brought about by blowing hot gases such as air, nitrogen, or carbon dioxide, through the materials.  The subsequent treatment with the concentrated solutions may take place at normal or elevated pressures, and at temperatures ranging from 30 to 100 DEG  C., according to the nature of the salt employed and the concentration of the solution.  When using concentrated solutions it is advisable tos top the hydrolysis when acid celluloses or dextrins are formed, any further hydrolysis, for example, to sugars, being effected by more dilute salts solutions or dilute acids.  The cellulosic materials are preferably employed in the state of fibres, small pieces, chips, or powder.  Suitable materials are wood chips, sawdust and the like, sulphite pulp, sulphate pulp, or mechanical wood pulp. According to examples: (1) sulphite pulp is steeped in sodium bisulphate solution, the excess liquor drained off, and the mass pressed.  Concentration is effected in a vessel heated to 30 DEG  C. with the aid of carbon dioxide or nitrogen heated to 35 DEG  C.  The vessel is then closed, and the temperature maintained at 50 DEG  C. for 15 hours.  The dextrins formed may be separated in any convenient manner from other hydrolysis products, for example, the dextrin may be obtained substantially free from acid celluloses by filtration of its aqueous solution, while sugars may be removed by washing the dextrin with aqueous alcohol; (2) the hydrolysis is carried out with a hydrated copper sulphate or an aluminium sulphate solution, the solution being concentrated to 50-60 per cent and allowed to act for 3-5 hours at 50 DEG  C. to give a product consisting chiefly of acid celluloses; (3) a zinc chloride solution is concentrated in contact with sulphite pulp until two parts of zinc chloride are present to one part of water; the solution is allowed to act for 10 hours at 50 DEG  C., diluted with water and the hydrolysis continued at 100 DEG  C. to produce a solution comprising sugars, and (4) the solution obtained as a product in example (1) is diluted, the temperature raised to 80 DEG  C. for a further 20 hours, a solution comprising sugars being obtained.  Specification 354,820 is referred to.