Alcohol and Phenols: Alcohols are carbon atoms with a hydroxyl group (- OH) linked to one of their carbon atoms. Enols are compounds with a hydroxyl group linked to a double bond’s unsaturated carbon atom. Alkyl, alkenyl, alkynyl, cycloalkyl, and benzyl are all saturated carbons. On the other hand, suppose a hydroxyl group is connected to a benzene ring. These chemicals are referred to as phenols.
Monohydric alcohols (containing one OH group), dihydric alcohols (containing two OH groups), and trihydric alcohols (containing three OH groups) are the three types of alcohols.
Alcohol is employed in industry as well as in everyday life. Ethanol, for example, is a commonly used spirit for polishing wooden furniture. Sugar, cotton, and paper are all made up of group-containing compounds. Phenols may be found in a wide range of key polymers, such as Bakelite, and medications like Aspirin.
The oxygen of the hydroxyl group is attached to carbon in the structure of alcohols via a sigma bond, which is produced by the overlap of an sp3 hybridized orbital of C with an sp3 hybridized orbital of oxygen.
Alcohols and phenols have higher boiling points as the number of carbon atoms rises (increase in van der Waals forces). As branching grows, the boiling point of alcohol drops (decrease in Van der Waals forces due to decrease in surface area). The -OH group in alcohols and phenols has a hydrogen atom linked to an electronegative oxygen atom. As a result, it can generate stronger intermolecular hydrogen bonds than the amine.
Due to strong intermolecular hydrogen bonding, alcohols and phenols have greater boiling temperatures than other types of chemicals, such as hydrocarbons, ethers, and haloalkanes/haloarenes, amines with comparable molecular weights.
They have lower boiling points than carboxylic acid, which has a stronger hydrogen bond. Because van der Waals forces diminish as size reduces, boiling temperatures for isomeric alcohols decline as branching increases. Primary alcohol > secondary alcohol > tertiary alcohol is the boiling point order.
The boiling point of ethers is relatively low, equivalent to that of alkanes of comparable molecular mass, due to their reduced dipole moment and lack of H-bonding.
Because of their propensity to establish hydrogen bonds with water molecules, alcohols and phenols are soluble in water. As the size of the hydrophobic group grows larger, solubility declines (R). Alcohol in higher quantities is insoluble. Branching promotes solubility by reducing the surface area of the nonpolar hydrocarbon component.
n-butyl alcohol < isobutyl alcohol < sec-butyl alcohol < tert-butyl alcohol.
According to the JEE syllabus, all reactions involving the preparation of phenols are very important; other important reactions include electrophilic aromatic substitution reactions of phenols, such as Kolbe's and Reimer Tiemann reactions, dehydration reactions of alcohol, and oxidation reactions of alcohol, among others.
All of the reactions resulted in a significant quantity of coke production. Under the same reaction conditions, the alkylation of phenols by alcohols produced a mixture of 0- and C-alkylated products.
Alcohols and phenols are hydrocarbons with hydroxyl groups instead of one or more hydrogen atoms. If we look at prior year JEE question papers, we can see that at least two to three questions from this chapter are asked practically every year. The following are the main themes covered in this chapter:-