Membrane Chlor-Alkali Process

“…The increase in pH can be counteracted by careful addition of HCl to the anolyte. Plants operating without anolyte acidification run at an anolyte pH > 4 with 1.5–2% oxygen in the chlorine gas and produce 3.5–5.2 kg ClO 3 – /ton NaOH. , …”

Section: Introductionmentioning

confidence: 99%

Catalyzed and Uncatalyzed Decomposition of Hypochlorite in Dilute Solutions

Sandin

Karlsson

Cornell

2015

Ind. Eng. Chem. Res.

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Hypochlorite decomposition has been investigated by the combined measurement of aqueous concentrations of total hypochlorite, chlorate, and chloride, as well as that of evolved oxygen. In all experiments, the initial concentrations of NaOCl and NaCl were 80 mM, and the temperature was 80 °C. The pH was kept constant in the range 5−10.5. The uncatalyzed decomposition of hypochlorite and the formation of chlorate and oxygen were all found to be third order of the form r i = k i [HOCl] 2 [OCl − ], and k O 2 was determined to be 0.046 M −2 s −1 . A reaction mechanism in which oxygen and chlorate formation share an intermediate is proposed. Several compounds were tested for catalytic effects. The addition of chloride salts of cobalt and iridium showed catalytic effects on oxygen formation. The addition of iridium chloride also catalyzed the formation of chlorate with increasing selectivity for chlorate with increasing pH.

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“…It is modelled with synthetic solutions of pure sodium chloride. Production of chlorine and sodium hydroxide from sodium chloride by ME is a well-known technique largely used in industrial scale [4]. BMED is more and more applied to acidify organic salts to produce acids for industry [5,6].…”

Section: Introductionmentioning

confidence: 99%