Sodium diacetate explained

Sodium diacetate is a compound with formula . It is a salt of acetic acid. It is a colorless solid that is used in seasonings and as an antimicrobial agent.

Preparation and structure

The salt forms upon half-neutralization of acetic acid followed by evaporation of the solution. It can be viewed as the result of homoassociation, an effect that enhances the acidity of acetic acid in concentrated solution:

2 CH₃CO₂H + NaOH → Na⁺[(CH₃CO₂)₂H]⁻ + H₂O

Also described as the sodium acid salt of acetic acid, it is best described as the sodium salt of the hydrogen-bonded anion (CH₃CO₂)₂H⁻. The O···O distance is about 2.47 angstrom.^[1] The species has no significant existence in solution but forms stable crystals.

Applications

As a food additive,^[2] it has E number E262 and is used to impart a salt and vinegar flavor.

See also

• Sodium acetate

References

1. Barrow, Michael J.; Currie, Murdoch; Muir, Kenneth W.; Speakman, J. Clare; White, David N, J. "Crystal structures of some acid salts of monobasic acids. XVII. Structure of sodium hydrogen diacetate, redetermined by neutron diffraction" Journal of the Chemical Society, Perkin Transactions 2: Physical Organic Chemistry 1975, pp. 15-18.
2. Peter J. Taormina "Implications of Salt and Sodium Reduction on Microbial Food Safety" in CriticalReviews in Food Science and Nutrition, 2010, vol. 50, 209-227.