Sodium Diacetate

Brief overview

Sodium diacetate is a chemical compound with the formula NaH(C₂H₃O₂)₂, and it is extensively used in the food industry as an antimicrobial agent. Sodium diacetate is a free-flowing, dust-free, readily available acetic acid source. It is also called a sodium salt of acetic acid, and it’s separated from the hydrogen-bonded ions with an intermolecular distance of 2.47 A0. Sodium diacetate consists of an equal mixture of sodium acetate and acetic acid. Sodium diacetate crystals have free acetic acid firmly held into the crystal lattice of neutral sodium acetate, thereby masking the sharp odour of acetic acid. When exposed to an atmosphere with low relative humidity for a long time, the sodium diacetate molecule loses one molecule of acetic acid and changes to anhydrous sodium acetate.

Manufacturing Process

Sodium diacetate crystals are manufactured commercially by partial-neutralization of acetic acid followed by evaporation of the solution. The resultant sodium diacetate crystals are formed from the homo-association of acetic acid solution.

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

Food Industry

Sodium diacetate is exclusively used as a food flavouring agent due to its distinctive vinegar flavour. It is added as a preservative to prevent mould strain from developing on foodstuffs. It has good anti-microbial properties and helps improve the shelf life of many products. In the baking industry, it is added as an anti-rope additive. Rope is commonly caused by bacteria in the dough that causes clogging of machinery and renders the dough unsafe for consumption. Sodium diacetate terminates these bacteria.

Other Application

In the agriculture industry, it acts as a bacteriostatic agent to improve nutrient levels in livestock feeds and as a preservative for hay. It is added as a blending ingredient in kidney dialysis processes. Industry grade sodium diacetate is used as a pH regulator and stabilizing agent in the petroleum industry.