Alcohols, Phenols And Ethers

- Learn important concepts of the chapter
1
Alcohols:-

Method of preparation of alcohol from haloalkanes

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Haloalkanes when treated with a dilute aqueous solution of an alkali or silver oxide give corresponding alcohols.

Alcohols through hydration

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Alkenes can be converted to alcohols by direct or indirect addition of water in the presence of mineral acid by Markovnikov's or anti-Markovnikov's rule.

Preparation of alcohols by reduction of aldehydes and ketones

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Carbonyl compounds such as aldehydes and ketones can be reduced to alcohols by using reducing agents such as lithium aluminium hydride etc .Aldehyde always form primary alcohols while ketone form secondary alcohol.

Preparation of alcohols by grignard reagent

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Aldehyde with grignard reagent gives primary alcohol whereas ketone gives secondary and tertiary alcohol.

Dehydration by protonic acids

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Alcohols, when treated with protonic acid, produce alkenes.
2
Phenols:-

Prepare phenol by benzenesulphonic acid

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When sodium salts of aromatic sulphonic acids are fused with sodium hydroxide, sodium derivatives of phenol are obtained which on acidification yield phenol.

Phenols from Dow's process

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Phenols can be obtained by heating haloarenes with an aqueous solution of sodium carbonate or sodium hydroxide at about 573-623 K under high pressure.

Kolbe's reaction of phenols

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Phenoxide ion generated by treating phenol with sodium hydroxide is even more reactive than phenol towards electrophilic aromatic substitution. Hence, it undergoes electrophilic substitution with carbon dioxide, a weak electrophile. Ortho hydroxybenzoic acid is formed as the main reaction product.

Reimer-Tiemann reaction

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When phenol is treated with chloroform in the presence of aqueous sodium hydroxide at 340 K followed by hydrolysis, an aldehyde group is introduced into the ring mainly at o-position.
3
Ethers:-

Williamson synthesis

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