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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

The target substance is a reaction mass from blending of two components (benzotriazole solid and 25 % tetramethylammonium hydroxide water solution) followed by reaction with chlorine gas. This reaction is an exothermic reaction with Ea of -117 kJ/mol.

Cl2 (gas) + 2(CH3)4NOH --> (CH3)4NOCl + (CH3)4NCl + H2O + Heat

The main constituents of the target substance are tetramethylammonium hypochlorite and tetramethylammonium chloride. It also contains tetramethylammonium hydroxide as an impurity, and benzotriazole as a stabiliser. Tetramethylammonium hypochlorite is a strong oxidiser and comparable to other chlorinated bleaching agents.

The important fate and pathways of this substance are related to the available chlorine concentration (%), which describes the oxidising power of a chlorine containing solution as if all chlorine species present were available as Cl2. At equilibrium, the available chlorine of the target substance determined as Cl2-% varies between 7.7― 8.6 %

The target substance is marketed and used always as aqueous solution. Benzotriazole at low concentrations (0.07 to 0.17 %) is used as a stabiliser. The further water diluted formulation product is marketed and used in the EU. The solutions are alkaline and the pH range is within 10.5 to 12.3 at 10 % water solution.

The target substance is miscible in water and decomposes in water compartment. The estimated log Kow values for the reaction mass components are within a range of -4.18 to -1.89, and the estimated BCF factor around 3.16 L/kg (US EPA 2014). The substance is not considered as persistent and bioaccumulative.

The target substance is considered to degrade abiotically. Bio-degradation is not an important fate process for the substance. The organic chemical groups in the reaction products will be biodegradable but the ultimate decomposition reactions are based on the known reactions of free chlorine and resulting inorganic reaction products not relevant for biodegradation.

The shelf-life of the substance is around 3 months. The decomposition increases when the temperature increases. The manufacturer’s experimental data on the decomposition time versus temperature indicates that the shelf-life is 8295 days at 7 °C but drops to 198 days at 22 °C. The shelf-life at 45 °C and at 60 °C is 5 days and 1 day, respectively. In general, the reaction rate doubles for every 10 °C increase in temperature. In addition, sun light has been proved to increase the decomposition of free chlorine in bleaching agents and disinfectants (Nowell & Hoigne 1992)

Degradation in water

The active fraction is the hypochlorite ion, in an equilibrium with hypochlorous acid and chlorine which depends on the pH value. In the pH region of natural waters (pH > 4-8) and in the absence of free ammonia and amines, aqueous chlorine exits primarily as an equilibrium mixture of hypochlorite ions (ClO-) and its conjugate acid hypochlorous acid (HOCl). Degradation of HOCl is more rapid than the degradation of ClO-. Hypochlorous acid (HClO) is very unstable and it suddenly decomposes with formation of oxygen:

2 HOCl --> 2 HCl + O2

In an acidic medium at pH values of around 4, chlorine gas is formed:

HOCl + H+ + Cl --> Cl2+ H2O

Target substance itself doesn't contain chloramines or ammonia, but chloramines can be formed when hypochlorite is released to natural waters containing organic compounds and the dissolved chlorine reacts with ammonia. During this reaction three different inorganic chloramines are formed; monochloramine (NH2Cl), dichloramine (NHCl2) and trichloramine (NCl3). Free chlorine also reacts with organic matter to form halogenated by-products. Inorganic chloramines, free chlorine and organic chloramines are chemically related and can change into one another easily. The pH value determines which kinds of chloramines are formed. Trichloramines mainly form when the pH value is 3 or below. In an acidic medium at pH values of around 4, chloramine disproportionates to form dichloramine, which in turn disproportionates at pH values below 3 to form nitrogen trichloride. At low pH values, nitrogen trichloride dominates and between pH 3-5 dichloramine dominates. These equilibria are disturbed by the irreversible decomposition of both compounds.

When the pH value is 7 or above, dichloramine concentrations are the highest. When ammonia concentrations are higher, more di- and trichloramines are formed. None of these compounds can be found in isolated form. Chloramines are not persistent, however, they are more persistent than freely available chlorine compounds.

Due to the instability and highly reactive nature of available chlorine to hypochlorite, the target substance will disappear very rapidly when entering the environment. The ultimate reaction product is chloride. HOCl concentrations available in domestic discharges are completely eliminated in the sewer system before entering the activated sludge system.

Atmospheric degradation

Based on the evaporation rate (0.035 g/h/cm2 at 25 °C), the target substance is non-volatile and the estimated Henry’s law constants of the main constituents (4.41E-011 Pa m3/mol to 5.760 E-007 Pa m3/mol) indicate low evaporation to atmosphere from water (US EPA 2014).

In acidic environment (pH < 4) the target substance produces chlorine gas. Chlorine is removed from air primarily by direct photolysis (HSDB 2014). At tropospheric wavelengths the chlorine molecule (Cl2) undergoes photodissociation, forming two chlorine radicals, which abstract a hydrogen atom from any available organic molecule to form hydrochloric acid. A lifetime of 7.3 hours has been reported for the photolysis of chlorine (HSDB 2014).

At environmental pH values (6.5-8.5) half of the hypochlorite is in the undissociated form of hypochlorous acid and half is dissociated to the hypochlorite anion. Only the hypochlorous acid fraction is volatile, but the amount of hypochlorous acid that could volatilise from water into air is expected to be very low. The calculated half-life (Atkinson calculation) for hypochlorous acid in the atmosphere is 2750 hours, but there are indications that the half-life is shorter; only a couple of hours in cloud water (Nowell & Hoigné, 1992). The photolytic half-life of aqueous chlorine at the surface of a flat water body is about 12 min at pH 8, 37 min at pH 7, and 1 h at pH 6 when exposed as a horizontal layer to solar irradiation corresponds to clear sky. The lifetime of chlorine will increase with increasing depth in a water column, due to water constituents associated with dissolved organic material. In natural eutrophic lake waters,due to high DOC-content, significant photolysis will occur only within the top 0.5 m. (Nowell & Hoigné, 1992)

Photolysis of hypochlorous acid generates atomic chlorine and hydroxyl radicals

OH°: HOCl + hv --> HO° + Cl°

Thus, hypochlorous acid could participate in the atmospheric chlorine reaction routes. The estimated atmospheric half-lives for organic compounds, based upon average atmospheric concentrations of hydroxyl radicals and ozone, is 5.436 days when the estimated rate constant of 5.0592 E-12 cm3/molecule s is used (AOPWIN, US EPA 2014).

As a conclusion, the formation of hazardous organic halogenated compounds is not to be expected because of low evaporation rate of the target substance and relatively short atmospheric half-lives of free chlorine.

Terrestrial compartment

In soil, free active chlorine reacts rapidly with organic matter. The ultimate fate of hypochlorite in soil is its reduction to chloride. The soil adsorption coefficients of the main components are within 8.214 to 16.4 L/kg calculated by using MCI method (KOCWIN v2.00, US EPA 2014) indicating low adsorption potential to organic matter.