Patent GB-655056-A (GB)
Title: Improvements in method for repressing the generation of chloride dioxide
IPC: D06L3/08
Filed: 1948-01-06
Abstract: The generation of chlorine dioxide in aqueous chlorite solutions maintained at pH=3-7 and employed in the production and treatment of pulp for paper-making, is repressed by the inclusion in the solution of a water-soluble pyrophosphate or polyphosphate, e.g. sodium pyrophosphate, hexametaphosphate, tetrametaphosphate, tetraphosphate or tripolyphosphate, or the potassium salts. Hydrogen peroxide, or compounds yielding it, e.g. sodium percarbonate or perborate, may be present, the weight ratio of phosphate to peroxide being generally 0.01-8 : 1, and the total concentration ranging from 0.75 grams/1 to 75 grams/1.  Various salts, or acids such as formic, acetic or phosphoric acid, may be used to produce to desired pH value.  The temperature of treatment varies from 20 DEG  to 100 DEG  C. Specification 588,040 is referred to.ALSO:The generation of chlorine dioxide in aqueous chlorite solutions maintained at pH=3-7 and employed in the treatment of textile and other materials, is repressed by the inclusion in the solution of a water-soluble pyrophosphate or polyphosphate, e.g. sodium pyrophosphate, hexametaphosphate, tetrametaphosphate, tetraphosphate or tripolyphosphate, or the potassium salts. Hydrogen peroxide, or compounds yielding it, e.g. sodium percarbonate or perborate, may be present, the weight ratio of phosphate to peroxide being generally 0.01-8 : 1, and the total concentration ranging from 0.75 grams/1 to 75 grams/1.  Various salts, or acids such as formic, acetic or phosphoric acid, may be used to produce the desired pH value.  The invention finds application in the bleaching, oxidizing and other treatment of paper, textiles (wool, silk, cotton, linen, rayon, cellulose esters and ethers) and straw, and in the treatment of protein-like fibres such as nylon, casein, etc.  The temperature of treatment varies from 20 DEG  to 100 DEG  C.  Several examples are given. Specification 588,040 is referred to.ALSO:The generation of chlorine dioxide in aqueous chlorite solutions maintained at pH=3-7 is repressed by the inclusion in the solution of a water soluble pyrophosphate or polyphosphate, e.g. sodium pyrophosphate, hexametaphosphate, tetrametaphosphate, tetraphosphate or tripolyphosphate, or the potassium salts. Hydrogen peroxide, or compounds yielding it, e.g. sodium percarbonate or perborate, may be present, the weight ratio of phosphate to peroxide being generally 0.01-8 : 1, and the total concentration ranging from 0.75 grms./1. to 75 grms./1.  Various salts, or acids such as formic, acetic or phosphoric acid, may be used to produce to desired pH value.  The invention finds application in the pulping and bleaching of paper, in bleaching sponges, textiles (wool, silk, cotton, linen, rayon, cellulose esters and ethers) and straw, and in the treatment of oils, fats, waxes, and protein-like fibres such as nylon, &c.  The temperature of treatment varies from 20 DEG  to 100 DEG  C.  Several examples are given.  Specification 588,040 is referred to.ALSO:The generation of chlorine dioxide in aqueous chlorite solutions maintained at pH=3-7 is repressed by the inclusion in the solution of a water soluble pyrophosphate or polyphosphate, e.g. sodium pyrophosphate, hexametaphosphate, tetrametaphosphate, tetraphosphate or tripolyphosphate, or the potassium salts. Hydrogen peroxide, or compounds yielding it, e.g. sodium percarbonate or perborate, may be present, the weight ratio of phosphate to peroxide being generally 0.01-8 : 1, and the total concentration ranging from 0.75 grms./1 to 75 grms./1.  Various salts, or acids such as formic, acetic or phosphoric acid, may be used to produce the desired pH value.  The invention finds application in the bleaching or solubilizing of starch.  The temperature of treatment varies from 20 DEG  to 100 DEG C. Specification 588,040 is referred to.