Hello,Welcome to StudentBro.
Hello,Welcome to StudentBro.
Hello,Welcome to StudentBro.
Alcohols, phenols, and ethers are important classes of organic compounds containing oxygen. They exhibit distinct properties due to the presence of hydroxyl (-OH) or ether (-O-) functional groups. These compounds play a crucial role in industrial applications, biological systems, and pharmaceuticals. Understanding their structure, classification, and chemical reactions is essential for NEET aspirants.
Alcohols are organic compounds containing one or more hydroxyl (-OH) groups attached to a carbon atom. They follow the general formula CₙH₂ₙ₊₁OH.
Monohydric Alcohols – Contain one -OH group (e.g., Methanol, Ethanol).
Dihydric Alcohols – Contain two -OH groups (e.g., Ethylene Glycol).
Trihydric Alcohols – Contain three -OH groups (e.g., Glycerol).
Primary Alcohols (1°) – The -OH group is attached to a primary carbon (e.g., Ethanol).
Secondary Alcohols (2°) – The -OH group is attached to a secondary carbon (e.g., Isopropanol).
Tertiary Alcohols (3°) – The -OH group is attached to a tertiary carbon (e.g., Tert-Butanol).
Phenols are aromatic compounds in which the hydroxyl (-OH) group is directly attached to a benzene ring. Their general formula is C₆H₅OH.
Monohydric Phenols – Contain one -OH group (e.g., Phenol).
Dihydric Phenols – Contain two -OH groups (e.g., Catechol).
Trihydric Phenols – Contain three -OH groups (e.g., Pyrogallol).
Ethers are organic compounds in which an oxygen atom is bonded to two alkyl or aryl groups. They follow the general formula R-O-R'.
Symmetrical Ethers – Both alkyl/aryl groups are the same (e.g., Dimethyl Ether).
Asymmetrical Ethers – Alkyl/aryl groups are different (e.g., Methyl Ethyl Ether).
From Alkenes – Hydration of alkenes using acid-catalyzed reaction.
From Alkyl Halides – Nucleophilic substitution (SN1 or SN2) using aqueous KOH.
From Carbonyl Compounds – Reduction of aldehydes and ketones using LiAlH₄ or NaBH₄.
From Grignard Reagent – Reaction of Grignard reagents with carbonyl compounds.
From Benzene Sulfonic Acid – Fusion with NaOH.
From Diazonium Salts – Hydrolysis of benzene diazonium chloride.
From Cumene Process – Oxidation of cumene followed by acid hydrolysis.
Williamson’s Ether Synthesis – Reaction of sodium alkoxide with alkyl halide.
Dehydration of Alcohols – Acid-catalyzed dehydration at lower temperatures.
Higher boiling points due to hydrogen bonding.
Soluble in water due to the -OH group.
Lower members are colorless liquids, while higher alcohols are solids.
High boiling points due to strong hydrogen bonding.
Slightly soluble in water but highly soluble in organic solvents.
Have a characteristic odor.
Lower boiling points due to the absence of hydrogen bonding.
Insoluble in water but soluble in organic solvents.
Have a pleasant smell.
Oxidation – Primary alcohols oxidize to aldehydes and then to carboxylic acids.
Dehydration – Forms alkenes on heating with H₂SO₄.
Reaction with Sodium – Forms alkoxide and hydrogen gas.
Reaction with PCl₅/PCl₃ – Converts alcohols into alkyl chlorides.
Electrophilic Substitution – Nitration, sulfonation, halogenation.
Oxidation – Phenol oxidizes to quinones.
Reaction with NaOH – Forms sodium phenoxide.
Acidic Cleavage – Ethers react with HI or HBr to form alcohols and alkyl halides.
Autooxidation – Ethers form peroxides in the presence of oxygen.
Used in alcoholic beverages (ethanol).
Solvents in pharmaceuticals and cosmetics.
Fuel additives and disinfectants.
Antiseptics and disinfectants (phenol, cresol).
Preparation of bakelite and other resins.
Used in the production of drugs like aspirin.
Used as anesthetics (diethyl ether).
Solvents in industrial and chemical processes.
Used in petroleum refining.
Alcohols, phenols, and ethers are crucial in organic chemistry due to their wide applications in medicine, industry, and daily life. Understanding their classification, preparation, and reactions helps in mastering organic chemistry for NEET.
