Sodium Salts of (1-Hydroxyethylidene)bisphosphonic acid (2-3 Na:1)

Water solubility

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

secondary literature

Qualifier:

no guideline followed

Principles of method if other than guideline:

The typically achievable solubility is inferred from the concentration of commercial aqueous solution products.

GLP compliance:

no

Type of method:

other: Not stated

Remarks on result:

other: soluble

Conclusions:

The substance was reported as soluble in a secondary source to which reliability could not be assigned.

Reference 2

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

secondary literature

Qualifier:

no guideline followed

Principles of method if other than guideline:

The typically achievable solubility is inferred from the concentration of commercial aqueous solution products.

GLP compliance:

no

Type of method:

other: Not stated

Key result

Water solubility:

>= 19 - <= 21 other: %w/w

Conc. based on:

test mat.

Temp.:

25 °C

Remarks on result:

other: The commercial availability of aqueous solutions of HEDP (2-3Na) salt demonstrates the possiblity to prepare stable aqueous solutions up to this concentration.

Conclusions:

The commercial availability of aqueous solutions of the salt at approximately 19-21% w/w solution concentrations demostrates that the solubility must be at least 20% w/w.

Reference 3

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Qualifier:

no guideline followed

Principles of method if other than guideline:

No information on guideline used was reported.

GLP compliance:

not specified

Type of method:

other: Not stated

Key result

Remarks on result:

other: Disodium salt 7414-83-7 is freely soluble in water

Conclusions:

The substance was reported as freely soluble in water in a handbook or collection of reliable data.

Reference 4

Endpoint:

water solubility

Type of information:

other: Other data

Adequacy of study:

supporting study

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

secondary literature

Principles of method if other than guideline:

Not stated

Type of method:

other: Not stated

Water solubility:

250 g/L

Temp.:

20 °C

pH:

ca. 5

Details on results:

pH Concentration: 10 g/l at 20 °C

Conclusions:

A water solubility of 250 g/L at 20°C and pH 5 was reported for the substance in a secondary source to which reliability could not be assigned.

Description of key information

Water solubility: HEDP (2-3Na) is commercially available as aqueous solutions at typically approximately 20% w/w; these products are miscible in water. Furthermore, the commercial availability of aqueous solutions at this typical concentration shows that HEDP (2-3Na) salt is soluble up to at least 20% w/w. The disodium salt of HEDP is 'freely soluble' in water based on a standard chemical data handbook.

Key value for chemical safety assessment

Water solubility:

200 g/L

at the temperature of:

25 °C

Additional information

The substance HEDP (2-3Na) and its analogues are known to be highly hydrophilic and extremely water-soluble. HEDP (2-3Na) has a reported water solubility of 19-21% w/w. In addition, HEDP-2Na was reported as freely soluble in water. In another source document, a water solubility of 250 g/L at pH 5 and 20°C was reported for HEDP-2Na.

The parent acid (HEDP-H) substance was reported as very soluble in water with a concentration of 69% at 20°C but it is not clear from the source report whether this is expressed as %w/w, %v/v or %w/v. Since the solution density is much higher than 1, the equivalent water solubility in g/L using density and concentration is reported as ≥690 g/L. In addition, as the value is known to be extremely high, the exact value is considered not significant for the chemical safety assessment for human health or environment and this limit value is therefore sufficient and is considered to be reliable.

 

This conclusion is supported by a measured water solubility of 774 g/L at 20°C and pH 10.4 for the tetrasodium salt of HEDP (HEDP-4Na). In a secondary source, HEDP-4Na has a reported water solubility of 100-500 g/L.

A water solubility value of 680 g/L was reported in secondary literature for HEDP-H. The original reference was not available for review and no further information is available. The reliability of this result is not assignable and has been assigned to be supporting study.

Phosphonate salts are highly water soluble and are supplied as aqueous solutions. Free acids are less soluble than the salts; however, aqueous solutions in excess of l % active material can be prepared. The aqueous solutions of sodium and potassium salts are miscible in water.