Reaction product of Phenol, Sulphuric acid and Sodium hydroxide

Endpoint summary

Description of key information

Oral: non toxic
Dermal: non toxic
Inhalation: no sufficient data available

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Acute toxicity: via inhalation route

Endpoint conclusion

Endpoint conclusion:

no study available

Acute toxicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Additional information

Oral

Based OECD 401 test results, BPS CAS 80-09-1, LD50 values are greater than 2000 and 5000 mg/Kg respectively. Several LD50 values from different tests are available, as a supporting: they indicate that the acute oral toxicity of BPS is low.^{1 2 3}

2,4'-sulfonyldiphenol CAS 5397-34-2 is considered a low acute oral toxicant (C&L ECHA Inventory), but no data is available.

Also data on benzenesulfonic acid, 4-hydroxy-, sodium salt (1:1), CAS 825-90-1 is not available.

The substance is the salified form of phenol sulfonic acid, which is a very acidic substance (comparable to sulphuric acid) and is almost completely ionised in watery environments, even at low pH.

Oral route values for rat and mouse of 1900 and 1500 mg/kg bw respectively, are available; this toxicity is probably due more to thegastro-intestinal corrosive property than the effective toxicity of the substance.⁴

The product DCB 58 % is neutralized, thus, more realistic data on salified similar substances called hydrotropes, can be considered.

A category approach evaluation has been done for the sodium xylenesulphonate evaluation. The estimated toxicological property of this substance can be helpful (in read across as well) to understand the toxicity of sodium sulphonated phenols, part of the intermediate DCB.

The sodium xylenesulphonate is considered non toxic by acute oral exposure.⁵

Estimated lethal oral doses of phenol in adults vary widely, from 1 g to 65 g. The substance is already classified as an oral toxicant (category 3, H301).⁶

Dermal

Reported several data on BPS CAS 80-09-1, suggest a low hazard concern for acute dermal exposure (LD50 > 5000 mg/Kg/day bw).^{1 2 3}

In addition, the estimated Kp of BPS is 0.000767 cm/hr and this value suggests that it could be less skin absorbed (EPI Suite v. 4.11).

2,4'-sulfonyldiphenol CAS 5397-34-2 is considered a low acute dermal toxicant (C&L ECHA Inventory), but no data is available.

Also, data on benzenesulfonic acid, 4-hydroxy-, sodium salt (1:1), CAS 825-90-1 are not available.

The substance is the salified form of phenol sulfonic acid, which is a very acidic substance (comparable to sulphuric acid) and is almost completely ionised in watery environments, even at low pH. Taking into consideration its corrosive nature, studies would cause unnecessary harm to laboratory animals. Moreover, because of the high polarity and high water solubility, the substance would be expected to be absorbed into the systemic circulation to a minimal extent.⁴

The product is neutralized, thus, more realistic data on salified similar substances called hydrotropes, can be considered. 

A category approach evaluation has been done for the sodium xylenesulphonate.

The acute dermal LD50 for sodium xylene sulphonate is > 2000 mg/kg bw. A category approach evaluation has also been done and defined it as non toxic for the dermal exposure.⁵

In addition, in a modelling study of 2010, the 2.8% of dermal absorption (low value) was calculated for sodium xylenesulphonate.⁵

Phenol, CAS 108-95-2 is readily absorbed by dermal contact with phenol liquid or phenol vapour, so systemic effects can also result from dermal exposure. Several acute lethality assays have been reported; in fact the substance is already classified in the Annex VI of CLP as a dermal toxicant (category 3, H311).⁶

Inhalation

No data is available regarding the acute inhalation hazard of BPS CAS 80-09-1.

2,4'-sulfonyldiphenol CAS 5397-34-2 is considered a low acute inhalation toxicant (C&L ECHA Inventory), but no data are available.

Also, data on benzenesulfonic acid, 4-hydroxy-, sodium salt (1:1), CAS 825-90-1 is not available.

The substance is the salified form of phenol sulfonic acid, which is a very acidic substance (comparable to sulphuric acid).

The product is neutralized, therefore, data on salified sulphonated phenols (similar substances called hydrotropes), can be considered.

A category approach evaluation is available for the sodium xylenesulphonate. A read across evaluation was done to define the toxicity of sodium xylenesulphonate by inhalation and defined it as non toxic by inhalation exposure.⁵

Several acute lethality assays on phenol CAS 108-95-2 have been reported, in fact, the substance is already classified under CLP, annex VI, as an inhalation toxicant (category 3, H331).⁶

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 xylenesulphonate, CAS 1300-72-7;

⁶Toxicological review of phenol. EPA, IRIS, 2002, EPA/635/R-02/006.

Justification for classification or non-classification

Oral

In order to classify the whole mixture DCB for the oral toxicity, the available classification and the results of the reported studies of every known component has been taken into account.

4,4'-sulfonyldiphenol (BPS): non classified

Benzenesulfonic acid, 4-hydroxy-, sodium salt (1:1)- hydrotropes, sodium xilene sulphonate (category approach): non classified

2,4'-sulfonyldiphenol: H302 (C&L ECHA Inventory).

Phenol: H301

Approximately 48% of the organic part of the intermediate under registration is composed of BPS.

Approximately 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). A category approach based on the hydrotropes can be taken into account for the classification of the whole intermediate mixture DCB. In fact, the properties of the salified form can be covered in read across with sodium xylenesulphonate (data available).

2,4'-sulfonyldiphenol is present at ca 6%.

Phenol is present in a low concentration (1.8%), therefore, it does not influence the classification of the intermediate DCB for this endpoint.

According to the CLP Regulation 1272/2008/EC, 3.1 section, based on the information available, the intermediate DCB 58% is not classified as an acute oral toxicant.

Dermal

In order to classify the whole mixture for acute dermal toxicity, the available classification and the results of the reported studies of every known component has been taken into account.

4,4'-sulfonyldiphenol (BPS): non classified

Benzenesulfonic acid, 4-hydroxy-, sodium salt (1:1)- hydrotropes, sodium xilene sulphonate (category approach): non classified

2,4'-sulfonyldiphenol: H312

Phenol: H311

Approximately 48% of the organic part of the intermediate under registration is composed of BPS.

Approximately 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).

A category approach based on the hydrotropes can be taken into account for the classification of the whole intermediate mixture DCB. In fact, the properties of the salified form can be covered in read across with sodium xylenesulphonate (data available).

Phenol, a dermal toxicant, is present in a low concentration (1.8%), therefore, it does not influence the classification of the intermediate DCB for dermal toxicity.

According to the CLP Regulation 1272/2008/EC, 3.1 section, based on the information available, the intermediate DCB 58% is not classified as an acute dermal toxicant.

Inhalation

In order to classify the whole mixture DCB for inhalation toxicity, the available classification and the results of the reported studies of every known component has been taken into account.

4,4'-sulfonyldiphenol (BPS): no data

Benzenesulfonic acid, 4-hydroxy-, sodium salt (1:1)- hydrotropes, sodium xylenesulphonate (category approach): non classified

2,4'-sulfonyldiphenol: H332

phenol: H331

Approximately 48% of the organic part of the intermediate under registration is composed of BPS.

Approximately 14% of the organic part of the mixture is the salified form of the phenol sulfonic acid (p-APS), benzenesulfonic acid, 4-hydroxy-, sodium salt (1:1).

A category approach based on the hydrotropes can be taken into account for the classification of the whole intermediate mixture DCB. In fact the properties of the salified form can be covered in read across with sodium xylenesulphonated (data available; not classified).

Phenol, an inhalation toxicant, is present in a low concentration (1.8%). Therefore, it does not influence the classification of the intermediate DCB for inhalation toxicity.

Despite the limited data available, the classification is considered inconclusive, because data on the major component (ca. 48 %) is not available.