Acetic anhydride can be obtained at home in a fairly simple way using sulfur and bromine.
This method allows you to do without aggressive and highly toxic substances, although it contains one such substance - bromine.
Due to the fact that acetic anhydrideIt is used for the production of drugs and explosives, it is impossible to get it in a store of chemical reagents. As much as it is impossible to do, it is so difficult to get it at home. All industrial methods are in no way applicable at home. Therefore, a special method is needed here. A method using bromine was chosen.
The main reaction is:
8CH3COONa + S + 3Br2 = 4 (CH3CO) 2O + Na2SO4 + 6NaBr
Equipment and reagents
- Liebig's refrigerator (used on thin sections)
- sand bath
- flask cone, heat-resistant, with thin sections
- pull out drobe
- glass stick
- flask with ground glass stopper
- frying pan
- technical scales
- disposable syringe for 20 cm3
- sulfur, 999 test
- Sodium acetate anhydrous
Before using the laboratory glassware to warmTo remove moisture. It is inadmissible the presence of even the smallest amount of water, as a result of acetic anhydride will react with it with the formation of acetic acid.
Sulfur and sodium acetate
On a technical scale, weigh 3.3 g of sulfur and place in a flask with a ground lid. To leave.
Sodium acetate must be calcined before melting,Because it is hygroscopic. On technical scales weigh 66.5 g of salt, making a reserve of 1-1.5 g, i.e. Total 67.5-68 g. Place it in a frying pan and heat it until melting. Fire to make an average, to avoid charring the substance. As soon as the salt is straightened, pour it into a mortar and grind it into powder. It is necessary to do this before solidification. We heat it in a pan before melting. To heat is not very likely to be charred. Once it is completely melted, pour into a mortar, and after solidification, grind into a powder. Pour the powder into the reaction flask.
Sulfur solution in bromine
Since bromine is a poisonous substance, it is recommended to prepare the solution under the hood. You can make it yourself.
Before preparing the solution, place bromine for a few minutes in the freezer. Collect 15.5 cm3 of cooled bromine and pour into a flask with sulfur, close the fused stopper. Shake the flask before dissolving the sulfur.
Preparation of acetic anhydride
In a container with ice, place the flask with acetateSodium, insert a glass rod into it and slowly add a solution of sulfur in bromine. It is necessary to constantly stir. The solution can be heated. Strong heating is unacceptable! After the sulfur solution in bromine has adhered to a solution of sodium acetate, it is necessary to leave the flask in an ice container for a while. Bromine vapor may appear in the process. Do not pay attention to it. After 10 minutes, the mixture gently gently creamy. Continue to stir for 30 minutes.
The distillation of acetic anhydride
After this interval of time appearAcetic scent. You can start the distillation process. To do this, the prepared sand bath is heated to 155-160 degrees Celsius, while installing the installation in parallel: the refrigerator is attached to the flask using a Wurtz nozzle. The boiling point of anhydride is almost 140 degrees Celsius. It is important not to overheat! Temperature control is carried out using a remote thermocouple with a digital tester. The distilled anhydride can again be distilled by adding a little sodium acetate.