Dichloromethane As Decaffeinated Substance

Dichloromethane

Molecular Formula

CH₂Cl₂

Molecular weight

84.93 g/mol

Dichloromethane as decaffeinated substance

Methylene chloride:

Methylene chloride (CH2Cl2) is a colorless, odorless, and volatile liquid that belongs to the class of halogenated hydrocarbons. It has a boiling point of 39.8°C and a density of 1.326 g/cm3 at 20°C. Methylene chloride is miscible with many organic solvents, such as ethanol, hexane, and benzene, but immiscible with water. It is an excellent solvent for a wide range of compounds, including fats, oils, waxes, resins, polymers, and alkaloids such as caffeine. Methylene chloride is produced by the chlorination of methane or by the hydrolysis of chloroform.

Methodology:

The decaffeination process using methylene chloride involves several steps. First, the coffee beans are steamed or soaked in hot water to remove the outer layers of the husk and dissolve the caffeine at the surface. Then, the coffee beans are treated with methylene chloride, which extracts the caffeine selectively from the solution, leaving behind the desirable flavor and aroma compounds. After the extraction, the coffee beans are washed repeatedly with water to remove the residual methylene chloride and decaffeinated solution. Finally, the beans are dried and roasted as usual to produce decaffeinated coffee.

Advantages:

The use of methylene chloride as a decaffeinating substance has several advantages. First, it is a fast and efficient method that can remove up to 99.9% of caffeine from coffee beans. Second, it is a cheap and readily available solvent that can be purchased in large quantities from various chemical suppliers. Third, it does not affect the taste and aroma of coffee significantly, compared to other methods such as carbon dioxide, which can alter the flavor and reduce the quality of coffee. Fourth, it is a safe and non-toxic substance when used in accordance with good manufacturing practices. Methylene chloride has a low toxicity and is classified as a category B2 substance by the US Environmental Protection Agency, indicating that it is not a suspected human carcinogen.