Sodium diacetate

Sodium diacetate

Sodium diacetate
Names
Other names Sodium hydrogen acetate; Sodium acid acetate
Identifiers
CAS Number	126-96-5
3D model (Jmol)	Interactive image
ChemSpider	29100
ECHA InfoCard	100.004.378
UNII	26WJH3CS0B
SMILES CC(O)=O.CC([O-])=O.[Na+]
Properties
Chemical formula	C4H7NaO4
Molar mass	142.09 g·mol^−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Sodium diacetate is a compound with formula NaH(C
2H
3O
2)
2. 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, is best described as the sodium salt of the hydrogen-bonded anion (CH₃CO₂)₂H⁻. The O---O distance is about 2.47 Å.^[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. doi:10.1039/P29750000015
2. 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. doi:10.1080/10408391003626207

Salts and the ester of the acetate ion
AcOH																	He
LiOAc	Be(OAc)2 BeAcOH											B(OAc)3	ROAc	NH4OAc	AcOAc	FAc	Ne
NaOAc	Mg(OAc)2											Al(OAc)3 ALSOL Al(OAc)2OH Al2SO4(OAc)4	Si	P	S	ClAc	Ar
KOAc	Ca(OAc)2	Sc(OAc)3	Ti(OAc)4	VO(OAc)3	Cr(OAc)2	Mn(OAc)2 Mn(OAc)3	Fe(OAc)2 Fe(OAc)3	Co(OAc)2, Co(OAc)3	Ni(OAc)2	Cu(OAc)2	Zn(OAc)2	Ga(OAc)3	Ge	As(OAc)3	Se	BrAc	Kr
RbOAc	Sr(OAc)2	Y(OAc)3	Zr(OAc)4	Nb	Mo(OAc)2	Tc	Ru(OAc)2 Ru(OAc)3 Ru(OAc)4	Rh2(OAc)4	Pd(OAc)2	AgOAc	Cd(OAc)2	In	Sn(OAc)2 Sn(OAc)4	Sb(OAc)3	Te	IAc	Xe
CsOAc	Ba(OAc)2		Hf	Ta	W	Re	Os	Ir	Pt(OAc)2	Au	Hg2(OAc)2, Hg(OAc)2	TlOAc Tl(OAc)3	Pb(OAc)2 Pb(OAc)4	Bi(OAc)3	Po	At	Rn
Fr	Ra		Rf	Db	Sg	Bh	Hs	Mt	Ds	Rg	Cn	Nh	Fl	Mc	Lv	Ts	Og
		↓
		La(OAc)3	Ce(OAc)x	Pr	Nd	Pm	Sm(OAc)3	Eu(OAc)3	Gd(OAc)3	Tb	Dy(OAc)3	Ho(OAc)3	Er	Tm	Yb(OAc)3	Lu(OAc)3
		Ac	Th	Pa	UO2(OAc)2	Np	Pu	Am	Cm	Bk	Cf	Es	Fm	Md	No	Lr