Cresols

Cresols, or methylphenols, refer to three isomeric compounds: ortho-cresol (2-methylphenol), meta-cresol (3-methylphenol), and para-cresol (4-methylphenol). They are colorless to pale yellow liquids at room temperature and possess a characteristic phenolic odor. They are weakly acidic and behave as phenols, forming salts with bases and undergoing typical phenolic reactions. They are soluble in many organic solvents and only sparingly soluble in water.

Occurrence and production: Cresols occur naturally in coal tar and are produced commercially as components of coal tar derivatives and phenolic resin processing streams. They are often recovered as fractions containing methylphenols in refining and chemical processing of phenolic wastes. The three isomers have distinct boiling points and can be separated by distillation or other purification methods.

Physical and chemical properties: The three isomers share a common aromatic ring with a single methyl substituent, giving each compound similar reactivity patterns to phenol. They can undergo electrophilic aromatic substitution and form various derivatives such as sulfates and esters. Their physical properties—such as boiling points and vapor pressures—differ enough to allow separation by standard purification techniques.

Applications: Cresols are used as chemical intermediates in the manufacture of resins, dyes, pesticides, and disinfectants. They also function as solvents in certain industrial processes and may appear as trace constituents in some chemical formulations. Use and handling are typically governed by industrial safety and environmental regulations.

Safety and environmental aspects: Cresols are toxic and corrosive to skin and eyes and irritant upon inhalation. They can be harmful if absorbed through the skin and pose risks with long-term exposure. They are hazardous to aquatic life and can persist in the environment. Proper handling, ventilation, personal protective equipment, and waste management are essential, in accordance with applicable regulations.