Hydrochloric acid

Production

Direct synthesis

The large scale production of hydrochloric acid is almost always integrated with other industrial scale chemical production. In the chlor-alkali industry, salt solution is electrolyzed producing chlorine, sodium hydroxide, and hydrogen. The pure chlorine gas can be re-combined with the hydrogen gas, forming chemically pure HCl gas. As the reaction is exothermic, the installation is called a HCl oven.

Related Topics:
Production - Chlor-alkali - Salt - Electrolyzed - Chlorine - Sodium hydroxide - Hydrogen - Exothermic - Oven

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:: Cl2 + H2 → 2HCl

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The resulting pure hydrogen chloride gas is absorbed in demineralized water, resulting in chemically pure hydrochloric acid.

Related Topics:
Hydrogen chloride - Absorbed - Demineralized

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Organic synthesis

The largest production of hydrochloric acid is integrated with the formation of chlorinated and fluorinated organic compounds, e.g., Teflon, Freon and other CFCs, chloro-acetic acid, and PVC. Often this production of hydrochloric acid is integrated with captive use of it on-site. In the chemical reactions, hydrogen atoms are replaced by chlorine atoms, whereupon the released hydrogen atom re-combines with the spare atom from the chlorine molecule, forming hydrogen chloride. Fluorination is a subsequent chlorine-replacement reaction, producing again hydrogen chloride.

Related Topics:
Production - Chlorinated - Fluorinated - Organic - Teflon - Freon - CFC - PVC - Chemical reaction - Atom

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:: R-H + Cl2 → R-Cl + HCl

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:: R-Cl + HF → R-F + HCl

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The resulting hydrogen chloride gas is either re-used directly, or absorbed in water, resulting in hydrochloric acid of technical or industrial grade.

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Industrial market

Hydrochloric acid is produced in solutions up to 38% HCl (concentrated grade). Higher concentrations up to just over 40% are chemically possible, but the evaporation rate is then so high, that storage and handling need extra precautions, such as pressure and low temperature. Bulk industrial grade is therefore 30% to 34%, optimized for effective transport and limited product loss by HCl vapours. Solutions for household purposes, mostly cleaning, are typically 10% to 12%, with strong recommendations to dilute before use.

Related Topics:
Concentration - Evaporation - Storage - Pressure - Temperature - Transport - Vapour

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Major producers worldwide include Dow Chemical at 2 million metric tonnes annually (2 Mt/year), calculated as HCl gas, and FMC, Georgia Gulf Corporation, Tosoh Corporation, Akzo Nobel, and Tessenderlo at 0.5 to 1.5 Mt/year each. Total world production, for comparison purposes expressed as HCl, is estimated at 20 Mt/year, with 3 Mt/year from direct synthesis, and the rest as secondary product from organic and similar syntheses. By far most of all hydrochloric acid is consumed captively by the producer. The open world market size is estimated at 5 Mt/year.

Related Topics:
Dow Chemical - FMC - Georgia Gulf Corporation - Tosoh Corporation - Akzo Nobel - Tessenderlo

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