Zinc acetate is a
salt with the
formula
In science, a formula is a concise way of expressing information symbolically, as in a mathematical formula or a ''chemical formula''. The informal use of the term ''formula'' in science refers to the general construct of a relationship betwee ...
Zn(CH
3CO
2)
2, which commonly occurs as the
dihydrate Zn(CH
3CO
2)
2ยท2H
2O. Both the hydrate and the
anhydrous
A substance is anhydrous if it contains no water. Many processes in chemistry can be impeded by the presence of water; therefore, it is important that water-free reagents and techniques are used. In practice, however, it is very difficult to achie ...
forms are colorless solids that are used as dietary supplements. When used as a
food additive
Food additives are substances added to food to preserve flavor or enhance taste, appearance, or other sensory qualities. Some additives have been used for centuries as part of an effort to preserve food, for example vinegar (pickling), salt (salt ...
, it has the
E number
E numbers ("E" stands for "Europe") are codes for substances used as food additives, including those found naturally in many foods such as vitamin C, for use within the European Union (EU) and European Free Trade Association (EFTA). Commonly ...
E650.
Uses
Zinc acetate is a component of some medicines, e.g.,
lozenges for treating the common cold. Zinc acetate can also be used as a dietary supplement. As an oral daily supplement it is used to inhibit the body's absorption of copper as part of the treatment for
Wilson's disease. Zinc acetate is also sold as an astringent in the form of an ointment, a topical lotion, or combined with an antibiotic such as
erythromycin
Erythromycin is an antibiotic used for the treatment of a number of bacterial infections. This includes respiratory tract infections, skin infections, chlamydia infections, pelvic inflammatory disease, and syphilis. It may also be used duri ...
for the topical treatment of acne. It is commonly sold as a topical anti-itch ointment.
Zinc acetate is used as the catalyst for the industrial production of
vinyl acetate from
acetylene
Acetylene (systematic name: ethyne) is the chemical compound with the formula and structure . It is a hydrocarbon and the simplest alkyne. This colorless gas is widely used as a fuel and a chemical building block. It is unstable in its pure ...
:
Approximately 1/3 of the worlds production uses this route, which because it is environmentally messy, is mainly practiced in countries with relaxed environmental regulations such as China.
Preparation
Zinc acetates are prepared by the action of
acetic acid
Acetic acid , systematically named ethanoic acid , is an acidic, colourless liquid and organic compound with the chemical formula (also written as , , or ). Vinegar is at least 4% acetic acid by volume, making acetic acid the main component ...
on
zinc carbonate or
zinc metal. Treatment of
zinc nitrate with
acetic anhydride
Acetic anhydride, or ethanoic anhydride, is the chemical compound with the formula (CH3CO)2O. Commonly abbreviated Ac2O, it is the simplest isolable anhydride of a carboxylic acid and is widely used as a reagent in organic synthesis. It is a col ...
is an alternative route.
Structures
In anhydrous zinc acetate the zinc is coordinated to four oxygen atoms to give a tetrahedral environment, these tetrahedral polyhedra are then interconnected by acetate ligands to give a range of polymeric structures.
In the dihydrate, zinc is octahedral, wherein both acetate groups are bidentate.
Reactions
Heating Zn(CH
3CO
2)
2 in a vacuum results in a loss of
acetic anhydride
Acetic anhydride, or ethanoic anhydride, is the chemical compound with the formula (CH3CO)2O. Commonly abbreviated Ac2O, it is the simplest isolable anhydride of a carboxylic acid and is widely used as a reagent in organic synthesis. It is a col ...
, leaving a residue of "basic zinc acetate," with the formula Zn
4O(CH
3CO
2)
6. It can also be prepared by a reaction of glacial acetic acid with
zinc oxide. The
cluster compound has a
tetrahedral structure with an oxide ligand at its center
Basic zinc acetate is a common precursor to
metal-organic frameworks (MOFs).
See also
*
Basic beryllium acetate - isostructural with basic zinc acetate
References
{{Acetates
acetate
An acetate is a salt (chemistry), salt formed by the combination of acetic acid with a base (e.g. Alkali metal, alkaline, Alkaline earth metal, earthy, Transition metal, metallic, nonmetallic or radical Radical (chemistry), base). "Acetate" als ...
zinc
E-number additives