Ethyl bromide

Ethyl bromide, also called bromoethane, is a volatile organic used as a ethylating agent. It's a very useful reagent to have. I plan to use ethyl bromide to make tert-pentanol and ethylamine. Ethyl bromide must be handled with care as it's a suspected carcinogen.

Ethyl bromide is easily prepared from ethanol, sulphuric acid and sodium bromide. I chose to use this method.

To a 1000ml round-bottom flask I added 74ml of ethanol and 50ml of water. I placed the flask of ethanol and water in an ice bath and slowly over the course of 30 minutes added 80ml of 98% sulphuric acid. I took care to ensure the mixture didn't heat up too much during the addition. After this, I added 70g of sodium bromide and set up for simple distillation. In the receiving flask I placed 25ml of water. I began distilling the mixture at a medium heat. Ethyl bromide began distilling over. When no more ethyl bromide passed over, the distillation was stopped.

The ethyl bromide had formed a layer underneath the water in the receiving flask. The ethyl bromide layer was collected with a syringe and washed with sodium bicarbonate solution. Then it was loaded into a watertight bottle and 25ml of sodium bicarbonate solution was added on top of the product to prevent it from evaporating. The lid was sealed with duct tape.
I got about 25ml of ethyl bromide which is roughly a 33.5% yield.

C2H5OH + H2SO4 ==> C2H5HSO4 + H2O  /  2 NaBr + H2SO4 ==> Na2SO4 + 2 HBr

C2H5HSO4 + HBr ==> C2H5Br + H2SO4