Sodium acetate
From Biocrawler, the free encyclopedia.
| Sodium acetate | |
| General | |
|---|---|
| Chemical formula | CH3COONa |
| Appearance | white solid |
| CAS number | 127-09-3 (anhydrous) 6131-90-4 (trihydrate) |
| Physical | |
| Molecular weight | 82 amu (132 when hydrated) |
| Melting point | decomposes at 597 K (324 °C) |
| Boiling point | n/a |
| Density | 1.45 g/cm3 |
| Crystal structure | orthorhombic |
| Solubility | 76 g/100 g of water |
| Thermochemistry | |
| ΔfH0gas | -? |
| ΔfH0liquid | ? |
| ΔfH0solid | ? |
| S0gas, 1 bar | ? |
| S0liquid, 1 bar | ? |
| S0solid | ? |
| Safety | |
| Ingestion | Large doses may cause abdominal pain, nausea and vomiting. |
| Inhalation | May cause irritation, with symptoms of coughing, sore throat, labored breathing, and chest pain. |
| Skin | May cause irritation (redness and/or pain). |
| Eyes | Chronic exposure may cause irritation, redness and pain. |
|
SI units and standard conditions used unless otherwise stated. | |
Sodium acetate, also known as sodium ethanoate, is used in a number of industries:
- Textile industry: to neutralize sulphuric acid and as a resist to aniline dyes
- Leather industry: as a pickling agent in chrome tanning
- Chemical industry: in the manufacture of diazo compounds
- Paper industry: as a buffering agent
- Rubber industry: to retard vulcanization of chloroprene (see neoprene)
- As a medium in phase change heat reservoirs
The last usage is seen in consumer heating pads. The contents (sodium acetate and water) are solid at normal temperature, but are heated in boiling water to melt the contents; after cooling, the clicking of a disk within the pad triggers the supercooled liquid to freeze and crystallise. The release of energy returns the pad to its freezing point of 54°C until it has fully solidified. The process is theoretically repeatable indefinitely, although the containing pouch will eventually break in practice.
Reactions
Sodium acetate can be used as a reagent to perform the esterification with ethanol
H3C-COO- Na+ + HO-CH2-CH3 + H+ ——> H3C-COO-CH2-CH3 + H-0-H
Hence, the reaction runs with sodium acetate in excess, and because sodium acetate binds 3 water molecules, this reaction, I read only once might be possible to be performed.
Synthesis of Sodium Acetate
Sodium acetate can be obtained easily by the reaction with of acetic acid with sodium hydrogen carbonate.
H3C-COOH + Na+[HCO3</sup>]-</sub> ——> H3C-COO- Na+ + H2CO3</sup>
The resulting carbonic acid hydrolyses quickly so the equilibrum is pushed to the right
