Reaction product of Phenol, Sulphuric acid and Sodium hydroxide

Endpoint summary

Additional information

The chemical intermediate "Dioxy Cuite Brute 58%" named "DCB" is a mixture of molecules and mainly composed of 4,4'-sulfonyldiphenol (BPS) and other sulfonated phenol sodium salts (from phenol sulfonic acidand phenol: see section 1.2 for the detailed composition).

DCB is soluble in water. The salified form increases the solubility of the molecules compared to the acid form.

Different results from studies on Bisphenol S (BPS) and sodium sulphonated phenols (hydrotropes, as sodium xylene sulphonate) are available, that permit to estimate the hazard of the salified sulphonated intermediate under registration.

Approximately the 48% of the organic part of the intermediate is composed by BPS (CAS 80-09-1).

Approximatelythe 14% of the organic part of the mixture is the salified form of the phenol sulfonic acid, the benzenesulfonic acid, 4-hydroxy-, sodium salt (1:1), CAS 825-90-1, which in its acid form is a very acidic substance.

In this case, a category approach based on the salified sulfonic acids (hydrotropes) can be taken into account for the hazard evaluation of the whole intermediate mixture DCB 58%. The specific cation is not expected to have an appreciable effect on fate, ecotoxicity or mammalian toxicity and therefore the dataset for the entire hydrotropes category can be applied broadly.

The 2,4'-sulfonyldiphenol CAS 5397-34-2 is present at 6%.

Phenol is present at 1.8%.

Hydrolysis

Hydrolysis is a common degradation route in the environment, where reaction of a substance RX with water occurs with a net exchange of the X group by an OH at the reaction centre, such that RX + H2O→ROH + HX.

For the substance, it can be estimated that hydrolysis does not occur because there are no hydrolysable groups in any of the structures.

Hydrolysable organic groups are in fact those groups that can react with water like Esters, Anhydrides, Amides, Carbammates, Nitriles, Cyanates, Epoxides, Halomethanes, Alkylhalides and Urea, and none of these groups are present within the substance or its impurities.

The difference in sulphonation can have an influence on water solubility, but not on the hydrolysation potential, since both substances have no hydrolysable groups in the chemical structure.

Biodegradation

After 28 days, no biodegradation of BPS was reported in a OECD Guideline 301 C test and it did not pass a Japanese MITI ready biodegradability test (0% after 4 weeks).^{1 2 4}

In a Chen et al. study, BPS aerobic degradation was not detected after 2 weeks.³

No data are available for 2,4'-sulfonyldiphenol CAS 5397-34-2.

No data are also available onbenzenesulfonic acid, 4-hydroxy-, sodium salt (1:1), CAS 825-90-1.

From non-standard tests on hydroxybenzenesulphonic acid, it seems likely that hydroxybenzenesulphonic acid is not readily biodegradable.⁵

On the other hand, the studies with salts of aromatic sulphonic acids called hydrotropes provide a valid read-across.

7 studies on hydrotropes support a conclusion of ready biodegradability.⁶

A conclusion on DCB 58% can be drawn based on the main component BPS and the similar substances hydrotropes, therefore the intermediate is considered as not readily biodegradable.

References:

¹ECHA Registration Dossier BPS CAS 80-09-1;

²SIDS INITIAL ASSESSMENT PROFILE, CAS 80-09-1, CoCAM 4, 16-18 April 2013;

³Min-Yu Chen, Michihiko Ike and Masanori Fujita, Acute toxicity, mutagenicity, and estrogenicity of bisphenol-A and other bisphenols. Environmental Toxicology Volume 17, Issue 1, pages 80–86, 2002;

⁴EPA, U. S. Environmental Protection Agency, Bisphenol A alternatives in thermal paper, Final Report, January 2014;

⁵HPV Assessment Report On Hydroxybenzenesulphonic acid CAS No. 1333-39-7, 2004, NOTOX;

⁶ECHA Registration Dossier, Sodium xylenesulphonate, CAS 1300 -72 -7; ECHA Registration Dossier, Toluene sulphonic acid CAS 104-15-4

Bioaccumulation

A bioaccumulation study in fish was conducted according to OECD Guideline 305 C on BPS. The species Cyprinus carpio were exposed to the test substance over a period of 6 weeks at test concentrations of 50 and 500 µg/L, in a flow through system.

The BCF for the test substance was measured to be very low (< 0.2 and < 2.2 at test concentrations of 500 and 50 µg/L). Thus, a bioaccumulation of the test substance to aquatic organisms is not expected.^{1 2}

The low concern for bioaccumulation was based on two experimental BCF values.³

No data are available for 2,4'-sulfonyldiphenol CAS 5397-34-2.

No data are also available on benzenesulfonic acid, 4-hydroxy-, sodium salt (1:1), CAS 825-90-1.

In principle, the salts of aromatic sulphonic acids called hydrotropes, that can be considered for a read across, get dissociated when in contact with water, to form the acids again. The aromatic sulphonic acids are soluble in water and are neither sorptive, nor volatile, nor bioaccumulative.⁴

Furthermore, BCF measured on the hydrotrope, sodium p-toluen sulphonate was found to be less than 2.3.⁵

  As a conclusion, the DCB 58% is considered as not bioaccumulative.

References:

¹ECHA Registration Dossier BPS CAS 80-09-1;

²SIDS INITIAL ASSESSMENT PROFILE, CAS 80-09-1, CoCAM 4, 16-18 April 2013;

³EPA, U. S. Environmental Protection Agency, Bisphenol A alternatives in thermal paper, Final Report, January 2014;

⁴HPV Assessment Report On Hydroxybenzenesulphonic acid CAS No. 1333-39-7, 2004, NOTOX;

⁵ECHA Registration Dossier, Sodium xylene sulphonate, CAS 1300-72-7; ECHA Registration Dossier, Toluene sulphonic acid, CAS 104-15-4

Transport and distribution

The transport evaluation for BPS is based on located experimental and estimated physical and chemical properties.

Based on the Level III fugacity models incorporating the located experimental property data, BPS is expected to partition primarily to soil. It is expected to exist in both neutral and anionic forms at environmentally relevant pH, based on its measured pKa. The neutral form of BPS is expected to have slight mobility in soil based on its estimated Koc. The anionic form may be more mobile, as anions do not bind as strongly to organic carbon and clay due to their enhanced water solubility. However, leaching of BPS through soil to groundwater is not expected to be an important transport mechanism.

Estimated volatilization half-lives indicate that it will be non volatile from surface water.

In the atmosphere, BPS is expected to exist in the particulate phase, based on its estimated vapour pressure. Particulates will be removed from air by wet or dry deposition.¹

Distribution in the environment of the salified form of phenol sulphonic acid (APS) was evaluated with Mackay Level III and is expected to partition primarily to soil (83%).²

As a conclusion, the intermediate DCB 58% is expected to partition primarily to soil.

References:

¹EPA, U. S. Environmental Protection Agency, Bisphenol A alternatives in thermal paper, Final Report, January 2014;

²Mackay Model, Level III, EPI SUITE, by EPA