Abstract: The present invention relates to a method for preparing dithionite solution with a reaction wherein sodium bisulfite is reduced with sodium borohydride solution to obtain dithionite, wherein the rise of the pH of the solution is prevented by adjusting the pH with carbon dioxide.

Abstract: Disclosed, among other things, are packaged bisulfite solutions comprising bisulfite reagent in an oxygen-impermeable container and methods.

Abstract: A method for brightening virgin mechanical pulp. The method comprises combining: (i) an aqueous solution comprising sodium borohydride and sodium hydroxide; and (ii) an aqueous solution comprising sodium bisulfite, in a chemical mixer and adding output of the chemical mixer to an aqueous slurry of virgin mechanical pulp. The ratio of (moles bisulfite?moles hydroxide)/moles borohydride is from 0 to 7.8.

Abstract: Iodine or iodophor stain resistance is imparted to a surface by applying a hardenable coating composition containing an effective amount of a reducing agent having a redox potential sufficient to decolorize an iodine or iodophor stain. The reducing agent reacts with triiodide anion in the stain to change the stain coloration from a yellowish hue (e.g., yellow-white, yellow or brown) towards a lighter hue (e.g., pale yellow, white or transparent). This decolorization reaction takes place over a period of minutes, hours or days, and preferably can eventually cause the stain to disappear.

Abstract: The end-blocked isocyanate prepolymer having an oxadiazine ring according to the present invention is characterized in that at least one of isocyanate groups of a NCO-terminated isocyanate prepolymer, which has NCO groups at the ends and comprises units derived from an oxadiazinetrione compound (A) represented by the following formula (1) and units derived from an active hydrogen compound (B) represented by the following formula (2), is blocked with a unit derived from an end-blocking agent (C) having at least one active hydrogen in one molecule, and that the end-blocked isocyanate prepolymer has a softening point of not lower than 50° C.

Abstract: The invention effectively prevents occurrence of corrosion in water tubes or the like of boilers. The invention provides a method for operating a boiler, including regulating a concentration of sulfate ions SO42− in boiler water to under 500 ppm, and a method for injecting a sulfite base oxygen scavenger, including setting a concentration of residual dissolved oxygen in boiler feed water to 2-4 ppm. The invention further provides a sulfite base oxygen scavenger composition comprising: 3-30 weight % of at least one selected from a group consisting of Na2SO3, K2SO3, NaHSO3 and KHSO3; 1-20 weight % of NaOH or KOH; 0.2-2 weight % of potassium sorbate; and 5-500 ppm of CoSO4.