Chlorine dioxide manufacture

Chlorate 700d X X (Disinfection by-product) preparation of chlorine dioxide manufacture of dyes, matches and explosives tanning and finishing leather herbicides and defoliants 111,3529... 

Large-Scale Industrial Production. Large amounts of chlorine dioxide ate used in pulp bleaching and smaller quantities ate used for the manufacture of sodium chlorite. In these appHcations, sodium chlorate is the only commercially available taw material. Chlorine dioxide production from sodium chlorate is achieved by the reduction of the chlorate ion in the presence of strong acid. The reaction consumes acid, so that acid and reducing agents must be constantly added to maintain the reaction. 

The commercial manufacture of sodium chlorite is based almost entirely on the reduction of chlorine dioxide gas in a sodium hydroxide solution containing hydrogen peroxide [7722-84-1] as the reducing agent. The chlorine dioxide is generated from the chemical or electrochemical reduction of sodium chlorate under acidic conditions. 

The principal U.S. manufacturers and/or water service companies that sold or leased chlorine dioxide generating equipment and services in 1991 were Aquatec, Capital Controls, Chemquip, Drew Chemical (Division of Ashland Chemical), Eischer Porter, Prominent Eluid Controls, Rio Linda, and Wallace Tiernan. 

R. M. Harrington, D. Gates, and R. R. Romano, "A Review of the Uses, Chemistry and Health Effects of Chlorine Dioxide and the Chlorite Ion, Chlorine Dioxide Panel of the Chemical Manufacturers Association, Washington, D.C., Api. 1989. 

Manufacture. Chloric acid is the precursor for generation of chlorine dioxide for pulp bleaching and other appHcations (see Bleaching agents), and is formed m situ by reaction of sodium chlorate [7775-09-9], NaClO, and a strong acid, eg. 

Holst A batch process for making chlorine dioxide by reducing sodium chlorate with sulfur dioxide in the presence of sulfuric acid. The sodium hydrogen sulfate byproduct can be used in the Kraft papermaking process. Developed by Moch Domsjo in Sweden, in 1946. Partridge, H. de V., in Chlorine, Its Manufacture, Properties, and Uses, Sconce, J. S., Ed., Reinhold Publishing, New York, 1962, 275. 

Twardowski Z (1989) Integrated process for the manufacture of chlorine dioxide and sodium hydroxide, US, US 4,806,215 Chem Abstr 111 176579v... 

Table 5-1 lists the facilities in each state that manufacture or process chlorine dioxide, the intended use, and the range of maximum amounts of chlorine dioxide that are stored on-site. There are 107 facilities that produce or process chlorine dioxide in the United States. Current estimates for the amounts of chlorine dioxide stored on-site as a by-product or impurity range from 99 to 9,999,999 pounds/year (45-4,539,510 kg/year) (TRIOO 2002). The data from the Toxics Release Inventory (TRI) listed in... 

The estimated release of 743,015 pounds (337,026 kg) of chlorine dioxide to the atmosphere from over 100 manufacturing, processing, and waste disposal facilities in 2000 accounted for about 72.7% of the estimated total environmental releases (TRIOO 2002). These releases are summarized in Table 6-1. The... 

In 2000, 0 pounds of chlorine dioxide were released to land from one manufacturing facility reporting releases of the compound to the environment (TRIOO 2002). Releases to the environment from facilities that produce, process, or use chlorine dioxide are summarized in Table 6-1. The data from the TRI should be used with caution since only certain types of facilities are required to report (EPA 1995). This is not a comprehensive list. 

There are several methods of manufacturing is on a commercial scale, for instance the calcination of oxalic add blended with potassium chloride, treatment of sodium chlorite with chlorine, or of sodium chlorate with sulphur dioxide in the presence of concentrated sulphuric add. Chlorine dioxide is utilized as a strong bleaching agent for cellulose, paper, flour, oils and such like, as well as a solvent for removing lignin from wood pulp. 

Perchloric Acid. Several techniques have been employed in the manufacture of perchloric acid, including thermal decomposition of chloric acid, anodic oxidation of chloric add. irradiation of chlorine dioxide solutions, electrolysis of hydrochloric acid, oxidation of hypochlorites by ozone, ion exchange, and electiodialysis of perchlorate salts. 

Sodium chlorite (NaC102) is manufactured from chlorine dioxide, sodium hydroxide, and calcium hydroxide. 

The manufacture of sodium chlorite starts from chlorine dioxide C102. It can easily be prepared in a laboratory by heating a mixture of powdered potassium chlorate and oxalic acid to 70 °C. The gas escaping will contain carbon dioxide and chlorine dioxide. 

Chlorine dioxide can also be manufactured by introducing a gaseous mixture of sulphur dioxide and air into a solution of sodium chlorate and sulphuric acid... 

An industrially important method of manufacturing chlorine dioxide is the decomposition of calcium chlorate by hydrochloric acid (see later Mathieson production method). 

Chlorine dioxide is manufactured on site as the gas cannot be stored in compressed form it is explosive under pressure. Several methods are used to generate chlorine dioxide. The most common method involves the reaction of chlorine gas with sodium chlorite to form chlorine dioxide and sodium chloride ... 

Theoretically, 1 pound of chlorine gas is required for each 2.6 pounds of sodium chlorite. In practice, however, an excess of chlorine is used to lower the pH to about 3.5 and drive the reaction to completion. In reality, the reaction never goes to completion, and there is always free chlorine in equilibrium with the chlorine dioxide. For this reason, membrane manufacturers discourage the use of chlorine dioxide for disinfecting RO systems.11... 

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