Work-up

In chemistry, work-up refers to the series of manipulations required to isolate and purify the product(s) of a chemical reaction.

The Grignard reaction between phenylmagnesium bromide (1) and carbon dioxide in the form of dry ice gives the conjugate base of benzoic acid (2).

The product is isolated from the mixture by the following work-up:[3] The reaction between a secondary amine (1) and an acyl chloride (2) yields the desired amide (4) as shown below.

The acyl chloride is added slowly to a solution of the amine and triethylamine in dichloromethane at 0 °C.

The following manipulations are then performed on the crude reaction mixture (3) to isolate the desired product:[4]

Synthesis of benzoic acid with work-up step in red.
Synthesis of 4-methylcyclohexene with work-up step in red.
Synthesis of an amide with work-up step in red.