Sodium hypochlorite: properties and applications

Sodium hypochlorite (NaOCl) is an inorganic compound whose aqueous solution is one of the most widely used disinfecting, bleaching and oxidising agents. Its molecular mass is 74.44. In industry and everyday life, sodium hypochlorite is known as the main active component of liquid bleaches, as well as a reagent for disinfecting drinking water and swimming pool water. Global sodium hypochlorite production is closely linked to the chlor-alkali industry and is measured in millions of tonnes per year.

Physicochemical Properties

Sodium hypochlorite is an aqueous solution with a characteristic chlorine odour. Concentrated solutions have a density of 1.2–1.25 g/cm³ and a pH in the range of 11.5–13.0. The solution is stable in the temperature range from minus 10 to plus 30 °C. Sodium hypochlorite is a strong oxidising agent and exhibits a broad spectrum of antimicrobial activity. Its effectiveness as a disinfectant is due to the formation of undissociated hypochlorous acid (HOCl), which is active as an antimicrobial compound. Hypochlorite is effective against most bacteria, fungi, yeasts, algae, viruses and protozoa, but is relatively ineffective against spores. The solution is rapidly inactivated in the presence of organic matter.

Production Technologies

Industrial sodium hypochlorite production is based on two main methods. The first method is the chlorination of an aqueous sodium hydroxide solution with electrolytic chlorine or off-gases. The reaction proceeds according to the equation: 2NaOH + Cl₂ → NaClO + NaCl + H₂O. Chlorination is carried out by bubbling chlorine through an alkali solution (18–22 wt. %) in chlorinators with cooling to minus 20 °C. The process can be batch or continuous. The second method is the electrolysis of sodium chloride solution. In the electrolyser, gaseous chlorine is formed from the NaCl solution, which reacts with sodium hydroxide directly in the electrolytic cell to form sodium hypochlorite. Modern installations allow sodium hypochlorite to be produced directly at the point of consumption, which reduces the risks associated with transporting and storing an unstable product.

Applications

Sodium hypochlorite finds wide application in various industries. In water treatment, it is used for disinfecting drinking water in local and centralised water supply systems, as well as for disinfecting swimming pool water. In the food industry — for sanitising surfaces, equipment and pipelines. In medical institutions — for disinfecting premises, surfaces and medical instruments. In the textile and pulp and paper industries — for bleaching fabrics and pulp. In the chemical industry — as an oxidising agent and intermediate for the synthesis of other compounds. In everyday life — as a base for bleaching and cleaning agents. Sodium hypochlorite is also used for disinfecting wastewater and for controlling biofouling in cooling systems.

Regulatory Framework

In Russia and CIS countries, requirements for sodium hypochlorite are regulated by a system of state standards. Technical specifications for sodium hypochlorite obtained by chlorination of an aqueous sodium hydroxide solution are established by GOST 11086-76. For the aqueous sodium hypochlorite solution obtained by electrolysis of sodium chloride solution in a membrane electrolyser, GOST R 57568-2017 applies. Sodium hypochlorite belongs to substances with moderate toxicity. High chlorine concentrations can cause metal corrosion, skin and mucous membrane irritation, as well as side effects in people suffering from asthma.

Global Production and Market

Estimates of the global sodium hypochlorite market volume vary depending on the methodology. According to Fortune Business Insights, the market was valued at USD 1.59 billion in 2025, projected to reach USD 1.64 billion in 2026 and USD 2.12 billion by 2034 at a CAGR of 3.20%. According to Mordor Intelligence, the market was valued at USD 352.76 million in 2025, USD 368.43 million in 2026, and is projected to reach USD 471.72 million by 2031 at a CAGR of 5.07%. According to Research and Markets, the market in 2026 is estimated at USD 950 million to 1.15 billion with a projected growth of 4.5–5.5% per year through 2031.

The Asia-Pacific region is the largest sodium hypochlorite market: in 2025, its share was 41.63% of global volume, with a projected growth rate of 5.87% per year. North America accounts for about 45% of the market, Europe — 22.7%. Key growth drivers are tightening sanitary standards, expansion of municipal water supply systems, the transition from gaseous chlorine to liquid forms for improved safety, and the development of local hypochlorite generation at the point of consumption. Main trends include the shift from gaseous chlorine to liquid and on-site generated alternatives, growing demand from the medical and food sectors, and expanding applications in the textile and pulp and paper industries.

Production in Russia

The Russian sodium hypochlorite market is characterised by a predominance of local production. According to market analysis, the hypochlorite market volume stabilised at 310,600 tonnes in 2024, while domestic production continued to grow, reaching 289,000 tonnes in 2025. The leader in import supplies to Russia in 2025 is China (over 99%). The largest sodium hypochlorite producer in Russia is JSC Bashkir Soda Company (Sterlitamak), whose product — technical sodium hypochlorite grade A — was recognised in the "100 Best Products of Russia" programme in 2025. Sodium hypochlorite is also produced at the facilities of Oxaide, Khimprom (Kemerovo), Novomoskovsk Chlor and others. In 2025, construction of a workshop for the production, storage and dosing of low-concentration sodium hypochlorite was underway in Izhevsk. The Moscow sodium hypochlorite plant produces 20,000 tonnes of NaOCl per year.

Safety and Storage

Sodium hypochlorite belongs to substances with moderate toxicity. Solutions with a high active chlorine content cause skin and mucous membrane irritation, and vapours can irritate the respiratory tract. When working with sodium hypochlorite, personal protective equipment must be used: rubber gloves, protective goggles, and protective clothing. Premises must be equipped with effective ventilation. Storage is carried out in hermetically sealed containers made of alkali-resistant materials (polyethylene, polypropylene), away from acids, reducing agents and organic substances. The solution is unstable and gradually decomposes with loss of active chlorine, so storage periods are limited and the product is recommended to be used within a few weeks of manufacture.

Conclusion

Sodium hypochlorite remains one of the key products of the global chemical industry, providing water disinfection, bleaching and oxidation across a wide range of industries. Population growth, rising hygiene standards, expansion of water supply systems and the transition to safer liquid chlorination forms create sustained demand for this essential chemical. China, the USA and European countries remain the leading players in the global sodium hypochlorite market, and the development of local generation technologies and expansion of production in Russia determine the industry's further prospects.