Acetic acid at normal temperature is a colorless liquid with a pungent characteristic odor. At temperatures below +16.6 °C, it solidifies into ice-like crystals, and hence it is called glacial acid. Acetic acid is soluble in water in any ratio. Its 3-5% aqueous solution is known as vinegar, which is used as a food condiment. 70-80% acetic acid is called acetic essence.
To get 98-99% acid, you have to get rid of the water that is present in it. The simplest method is freezing. This method is sometimes used in laboratories. It is practical and safe. A bottle of acetic acid is placed outdoors or in the freezer or in a cooling ice-salt mix until the content has completely solidified (pure acetic acid freezes at +16.64 ºC, water solutions, of course, at a lower temperature). Then gradually thaw (without heating, keeping at room temperature) periodically drain the thawed liquid. When at least 1/3 of the original volume of liquid has been drained, almost anhydrous acid will remain in the bottle. Repeated freezing gives 98-99.5% acid.
Anhydrous acetic acid has a melting point of 16.6 ºC, after which it changes to a crystalline state, in appearance with a piece of ordinary ice.
By draining the liquid fraction from such "frozen" acetic acid, a higher concentration of it in solid form is obtained.
Ice-cold acetic acid is acetic acid that turns to ice at about 16.6 ºC, which is an indicator of its dehydration.
To get 98-99% acid, you have to get rid of the water that is present in it. The simplest method is freezing. This method is sometimes used in laboratories. It is practical and safe. A bottle of acetic acid is placed outdoors or in the freezer or in a cooling ice-salt mix until the content has completely solidified (pure acetic acid freezes at +16.64 ºC, water solutions, of course, at a lower temperature). Then gradually thaw (without heating, keeping at room temperature) periodically drain the thawed liquid. When at least 1/3 of the original volume of liquid has been drained, almost anhydrous acid will remain in the bottle. Repeated freezing gives 98-99.5% acid.
Freezing point of acetic acid aqueous solutions.
| Acetic acid content, % | Freezing point, °C | Acetic acid content, % | Freezing point, °C |
| 100.0 | +16.64 | 61.86 | –24.20 |
| 99.00 | +14.80 | 55.50 | –22.30 |
| 97.00 | +11.81 | 50.60 | –19.80 |
| 93.46 | +7.10 | 41.50 | –15.90 |
| 90.09 | +3.60 | 30.10 | –10.90 |
| 86.96 | –0.20 | 16.21 | –5.20 |
| 80.65 | –7.40 | 11.85 | –3.91 |
| 66.44 | –20,.0 | 6.50 | –2.09 |
Anhydrous acetic acid has a melting point of 16.6 ºC, after which it changes to a crystalline state, in appearance with a piece of ordinary ice.
By draining the liquid fraction from such "frozen" acetic acid, a higher concentration of it in solid form is obtained.
Ice-cold acetic acid is acetic acid that turns to ice at about 16.6 ºC, which is an indicator of its dehydration.
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