Chemistry > Alcohols, Phenols and Ethers > 6.0 Chemical properties of alcohols
Alcohols, Phenols and Ethers
1.0 Alcohols
2.0 Classification of alcohols
3.0 Physical properties of the alcohol
3.0 Physical properties of the alcohols
4.0 Preparation of Alcohol
4.1 By hydrolysis of alkyl halide
4.2 Acid catalysed hydration of alkenes
4.3 Oxymercuration Demercuration
4.4 Hydroboration-oxidation
4.5 Hydroxylation of alkenes
4.6 From organometallic compounds
4.6 Reduction of Esters
5.0 Grignard reagent
5.1 Reaction & Mechanism
5.2 Product of Grignard reagent
5.3 Planning a Grignard synthesis
5.4 Restriction of the use of Grignard reagents
6.0 Chemical properties of alcohols
6.1 Acidic character
6.2 Dehydration
6.3 Reaction with phosphorus trihalide or thionyl chloride
6.4. Reaction with hydrogen halide
6.5 Oxidation of Alchols
7.0 Tests for Alchols
8.0 Ethers
9.0 Chemical Properties of Ethers
10.0 Aryl Ethers
11.0 Epoxides
12.0 Phenols
13.0 Preparation of Phenol
14.0 Physical Properties of Phenol
15.0 Chemical properties of phenols
6.3 Reaction with phosphorus trihalide or thionyl chloride
4.2 Acid catalysed hydration of alkenes
4.3 Oxymercuration Demercuration
4.4 Hydroboration-oxidation
4.5 Hydroxylation of alkenes
4.6 From organometallic compounds
4.6 Reduction of Esters
5.2 Product of Grignard reagent
5.3 Planning a Grignard synthesis
5.4 Restriction of the use of Grignard reagents
6.2 Dehydration
6.3 Reaction with phosphorus trihalide or thionyl chloride
6.4. Reaction with hydrogen halide
6.5 Oxidation of Alchols
Phosphorus is water-soluble and may be removed by washing the alkyl halide with water or dilute aqueous base
Mechanism: The mechanism for the reaction involves attack of an alcohol group on the phosphorus atom displacing a bromide ion and forming protonated alkyl dibromo phosphite.
In a second step a bromide ion acts as a nucleophile to displace HOPBr2 a good leaving group due to the electronegative atoms bonded to the phosphorus.
(i).Since tertiary alcohols are readily converted into tertiary halides phosphorous trihalide and thionyl chloride are mainly used for preparing primary and secondary halide.
(ii).Since carbocations are not formed as intermediates the reactions with both the reagents occur without rearrangement.
