Organic Chemistry Notes PDF

# Phenol: Chemical Reactions * **Electrophillic aromatic Substitution** - **Nitration** - **Halogenation** - **Kolbe's reaction** - **Reimer- Tiemann Reaction** # Phenol: Halogenation When phenol is treated with Bromine in solvents of low polarity such as CHCl₃ or CS₂ and at low temperat...

# Phenol: Chemical Reactions * **Electrophillic aromatic Substitution** - **Nitration** - **Halogenation** - **Kolbe's reaction** - **Reimer- Tiemann Reaction** # Phenol: Halogenation When phenol is treated with Bromine in solvents of low polarity such as CHCl₃ or CS₂ and at low temperature, monobromophenols are formed. # Phenol: Kolbe's Reaction * **Mechanism:** ```text OH | C6H5-O⁻ | H ``` + NaOH ---> ```text OH | C6H5-O⁻ | Na ``` + H₂O ```text OH | C6H5-O⁻ | Na ``` + CO₂ ---> ```text OH | C6H5-COO⁻ | Na ``` # Phenol: Reimer - Tiemann Reaction On treating phenol with Chloroform in the presence of Sodium hydroxide, a -CHO group is introduced at o or p position of benzene ring. # Tertiary Alcohols do not undergo Oxidation ## Reaction * **Tertiary Alcohol:** ```text O-H | R-C-R3 | R2 ``` * **Carbonylic acid:** R-C=O # Example: RCH₂OH (Oxidation) ---> R-C=O (Aldehyde) ---> R-C=O (Carbonylic acid) Strong oxidizing agents such as acidified Potassium permanganate are used for getting carboxylic acids from alcohols directly. * **Primary Alcohol:** R-CH₂-OH (KMnO₄) ---> R-C OH (Carboxylic acid) * **CrO₃** in anhydrous medium is used as the oxidizing agent for the isolation of aldehydes. RCH₂OH (CrO₃) ---> RCHO * **Primary alcohols are oxidised to aldehydes in good yield by Pyridinium Chlorochromate (PCC)** CH₃-CH=CH-CH₂OH (PCC) ---> CH₃-CH=CH-CHO * **Secondary alcohols are oxidised to ketones by chromic anhydride (CrO₃).** R-CH-R' (CrO₃) ---> R-C-R' # Ex- 2° alcohol * **85%H₃PO₄, 440K:** ```text OH | CH₃CH CH₃ ``` ---> CH3-CH=CH₂ + H₂O * **20%. H₃PO₄, 358k:** ```text CH3 | CH₂-C-OH | CH₃ ``` ---> CH3 - C - CH₃ + H₂O # relative case of dehydration of alcohols 3>2°>1° # Alcohol: Oxidation ```text H-C-O-H ↑↑ Bond Breaking ``` ---> C=0 Oxidation of alcohols involves the formation of carbon-oxygen double bond with cleavage of an O-H and C-H bonds. • Oxidation reactions are also called dehydrogenation reactions as these involve loss of hydrogen from an alcohol molecule. # 0-Nitrophenol is steam volatile due to intermolecular hydrogen bonding. ```text H | O-Nitro phenol ``` # P-nitrophenol is less volatile due to intermolecular hydrogen bonding which causes the association of molecules. ```text HO | P-nitrophenol ``` * **With concentrated nitric acid, phenol is converted to 2, 4, 6 trinitrophenol. The product is commonly known as picric acid** # Ethers ## Uses: * Useful as solvent for paints, perfumes, waxes, fats, oil etc. * Medicine- * Pain relief * Codeine Phosphate Syrup (Methoxy Methane) * Diethyl ether (Anaesthesia) ## Ether * There are formed when H atom in a hydrocarbon is replaced by an alkoxy or aryloxy group (R-O-R'). ## General formula: * R-O-R' ## Ether: Preparation * **Dehydration of Alcohol** * **Williamson Synthesis** ## Intro: * R-OH (Alcohol) + HOR (Alcohol) ---> R-O-R (Ether) + H₂O (Water) * **Example:** C₂H₃OH (Ethanol) + C₂H₃OH (Ethanol) ---> C₂H₃OC₂H₃ (Ether) + H₂O (Water) # Dehydration of Alcohol *Alcohols undergo dehydration in the presence of protic acids.*