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.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. The species has no significant existence in solution but forms stable crystals.
Applications As a food additive,Peter J. Taormina "Implications of Salt and Sodium Reduction on Microbial Food Safety" in Critical Reviews in Food Science and Nutrition, 2010, vol. 50, 209-227. it has E number E262. It is used both as a preservative and to impart a salt and vinegar flavor, for example in salt and vinegar chips.
See also Sodium acetate
References