Question

On a commercial scale, decaffeination is achieved using liquid CO2. What is an advantage of using liquid CO2 in place of dichloromethane?

Answer 1

When decaffeination is done commercially in large scale, using liquid carbondioxide is beneficial. Carbondioxide is a readily available compound. It is pressurized to make it liquid and is brought in contact with the beans from which CO2 takes away the caffeine and releases it when the pressure is lowered. The same CO2 is again used to extract. Hence, too much CO2 is not required as it is reused. But this is not the case with dichloromethane. It cannot be reused. Also, by using dichloromethane, some residual solvent might be present after the process but that is not the case with liquid CO2.