Paper, bleaching agents

Packing class, commercial codes, 621 Packing effect, dialkyl peroxides, 121 Palm olein, oxidative deterioration, 662 Pamctinal laser photocoagulation, 640 Paper, bleaching agents, 623 Parasites... 

This growth will substantially increase demand for surfactants, bleaching agents, complexing agents, and other chemicals used in paper recycling... 

Uses. The dominant use of sulfur dioxide is as a captive intermediate for production of sulfuric acid. There is also substantial captive production in the pulp and paper industry for sulfite pulping, and it is used as an intermediate for on-site production of bleaches, eg, chlorine dioxide or sodium hydrosulfite (see Bleaching agents). There is a substantial merchant market for sulfur dioxide in the paper and pulp industry. Sulfur dioxide is used for the production of chlorine dioxide at the paper (qv) mill site by reduction of sodium chlorate in sulfuric acid solution and also for production of sodium dithionite by the reaction of sodium borohydride with sulfur dioxide (315). This last appHcation was growing rapidly in North America as of the late 1990s. 

Production of Sodium Borohydride. In the pulp and paper industry, sodium borohydride is used to generate sodium hydrosulfite (sodium dithionite), a bleaching agent, from sodium bisulfite. Methyl borate is used as an intermediate in the production of sodium borohydride (33). 

Nearly 95% of the sodium chlorate produced ia North America is used to produce chlorine dioxide [10049-04-4] CIO2, for pulp (qv) bleaching (see Bleaching AGENTS, pulp and paper) (37). Minor amounts are used to produce other chemicals such as KCIO, NaC102, NaClO, etc, to recover uranium [7440-61-17, U (see Uraniumand uranium compounds) and for agricultural uses as a defoHant or herbicide (see Herbicides). 

Through this reaction, sodium peroxide finds use as a bleaching agent in the pulp and paper industry. 

Sulphur dioxide is used as a preservative for beer, wine and meats in the production of sulphites and hydrosulphites in solvent extraction of lubricating oils as a general bleaching agent for oils and foods in sulphite pulp manufacture in the cellulose and paper industries and for disinfection and fumigation. 

Sapoxal A pulp-bleaching process used in the paper industry. The bleaching agent is oxygen and the process is operated under alkaline conditions. 

---