Bleaching agent, sodium borohydride

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. [Pg.148]

The reducing agents generally used in bleaching include sulfur dioxide, sulfurous acid, bisulfites, sulfites, hydrosulfites (dithionites), sodium sulfoxylate formaldehyde, and sodium borohydride. These materials are used mainly in pulp and textile bleaching (see Sulfur compounds Boron compounds). [Pg.149]

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). [Pg.216]

Sodium Borohydride (NaBI-14). Sodium borohydride has been used mainly in the industrial bleaching of mechanical pulps. The BH4 ion is a strong reducing agent in alkaline solution. [Pg.156]