Reaction mass of dimethyl phosphonate and methyl hydrogenphosphonate and phosphonic acid

Water solubility

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

other information

Reliability:

4 (not assignable)

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

GLP compliance:

yes (incl. QA statement)

Water solubility:

> 1 067 g/L

Temp.:

20 °C

pH:

ca. 0

Conclusions:

The water solubitlity of phosphonic acid is > 1067 g/L

Reference 2

Endpoint:

water solubility

Type of information:

(Q)SAR

Adequacy of study:

other information

Reliability:

4 (not assignable)

Water solubility:

ca. 1 000 g/L

Reference 3

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

other information

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Acceptable, well documented publication which meets basic scientific principles

Reason / purpose for cross-reference:

reference to same study

Principles of method if other than guideline:

The investigation was carried out to study the stability of DMP under conditions similar to those that the chemical may encounter in the physiological environment (lungs, forestomach). Capillary gas chromatography (GC) was used to analyze DMP. The decomposition products of DMP were identified by HPLC and proton nuclear magnetic resonance spectroscopy (H-NMR).

GLP compliance:

no

Water solubility:

> 100 g/L

Temp.:

22 °C

pH:

> 2 - < 8

Preparation of 10 % (w/v) of dimethyl phosphonate solution in deionized water, in HCl at pH 2 and in 0.1M sodium phosphate buffer at pH 7 and pH 8 was possible at room temperature (22°C).

Hydrolysis was observed.

Hydrolysis products were:

monomethyl hydrogen phosphite and methanol and further phophorous acid and methanol.

pH values of all solutions decreased progressively as time passed.

Description of key information

There are no data for phosphonic ester residue with respect to water solubility available. However, there are studies with two of the components, dimethylphophonate (CAS 868-85-9) and phosphonic acid (CAS 13598-36-2) available indicating a water solublity > 100 g/L for dimethylphosphonate and 1067 g/L for phosphonic acid. Only for one component of phosphonic ester residue, methyl hydrogenphosphonate (CAS 13590-71-1) , there is no experimental study available. From a structural point of view, methyl hydrogenphosphonat has one methyl-group less than dimethylphosphonate and one methyl-group more than phosphonic acid. Thus, the water solubility of methyl hydrogenphosphonate is very likely to be above 100 g/L. Actually, QSAR calculation predicted for methyl hydrogenphosphonate a water solubility of 1000 g/L. 

Taking all information together, it is plausible to assume that the water solubility of phosphonic ester residue is above 100 g/L and probably close to 1000 g/L. However, hydrolysis may occure at contact with water.

Key value for chemical safety assessment

Water solubility:

1 000 g/L