Sodium lactate

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

November, 1941

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

Lactic acid had been prepared by the method of Smith and Claborn and an analysis (by a modified Eder and Kutter procedure) gave 60 % “directly titratable acid” and 102.0 % “total acid”, both expressed as lactic acid. It had the following physical properties: refractive index = 1.4361 (25 °C) and relative density = 1.2143 (25 °C).

The concentrated solution of sodium lactate salt was obtained by slow addition of a saturated solution of sodium hydroxide to the lactic acid. The reaction flasks were kept cool with an ice bath, as heat and a local excess of alkali caused discoloration. The resulting solution was more dilute than desired and was concentrated in vacuo, with the bath temperature kept below 50 °C. The solution contained a small amount of a gelatinous precipitate at this point , which was removed by filtering through Jena fritted glass filter. To ensure the absence of anhydrides, the final adjustments to the neutral point of phenolphthalein were made after the concentrated solutions had stood for one week, a procedure used by Dietzel and Rosenbaum in the preparation of pure sodium lactate for conductivity work.

The sodium content of the solutions was determined by decomposing them with sulfuric acid and weighing the corresponding sulfates. This procedure is satisfactory, as the alkalines used met the AMERICAN CHEMICAL SOCIETY specifications (Am. Chem. Soc., "Specifications for Analytical Reagent Chemicals",1941). The concentrated solutions were diluted to the desired concentrations with triple distillied water.

GLP compliance:

no

Type of method:

other: Gravimetric determination of precipitate.

Key result

Water solubility:

1 086 g/L

Conc. based on:

other: The sodium content of the solution was determined by weighing the sulfate precipitate after decomposition with sulfuric acid.

Temp.:

25 °C

Remarks on result:

other: pH not reported in the literature.

Details on results:

The maximum achievable concentration of Sodium lactate in water is approximately 77 % (w/w). The corresponding water solubility of the substance is reported to be approximately 108.66 g/mL. The sodium content of the solution was determined by weighing the sulfate precipitate after decomposition with sulfuric acid.

Conclusions:

The maximum solubility of Sodium lactate in water at 25 °C determined by gravimetric analysis is 1086 g/L (77.15 % w/w).

Executive summary:

A concentrated solution of Sodium lactate was obtained by slow addition of a saturated solution of sodium hydroxide to lactic acid. The sodium content of the solution was determined by gravimetric analysis (weighing of precipitate) after decomposition with sulfuric acid. The maximum solubility of Sodium lactate in water at 25 °C is 1086 g/L (77.15 % w/w).

Description of key information

A concentrated solution of Sodium lactate was obtained by slow addition of a saturated solution of sodium hydroxide to the lactic acid. The sodium content of the solution was determined by gravimetric analysis (weighing of precipitate) after decomposition with sulfuric acid. The maximum solubility of Sodium lactate in water at 25 °C is 1086 g/L (77.15 % w/w).

Key value for chemical safety assessment

Water solubility:

1 086 g/L

at the temperature of:

25 °C