Chemistry > Hydrocarbons > 10.0 Mechanism Of Some Important Reaction Of Alkenes
Hydrocarbons
1.0 Introduction
2.0 Alkanes
3.0 Methods of Preparation Alkanes
4.0 Physical Proparties
5.0 Chemical Properties
6.0 Alkenes
7.0 Methods of Preparation Alkenes
7.1 Dehydrohalgoenation
7.2 Dehydration of Alcohols
7.3 Dehalogenation
7.4 Thermal elimination reaction
7.5 By partial reduction of alkynes:
7.6 Wittig Reaction
7.7 Kolbe hydrocarbon synthesis
8.0 Physical Proparties
9.0 Chemical Properties
10.0 Mechanism Of Some Important Reaction Of Alkenes
10.1 Mechanism of halogen addition
10.2 Mechanism of halohydrin formation
10.3 Syn - hydroxylation
10.4 Oxidation reactions of alkenes
11.0 Alkynes
12.0 Methods of Preparation Alkynes
12.1 Industrial source
12.2 Kolbe’s method
12.3 Dehydrohalogenation of 1, 2 – dihalides
12.4 Dehydrohalogenation of 1, 1 – dihalides
12.5 Dehalogenation of tetrahalides or trihalides
12.6 Alkylation of acetylene and terminal alkynes
13.0 Physical Properties
14.0 Chemical Properteis
14.1 Electrophilic addition reactions
14.2 Acidity of Alkynes
14.3 Aromatic Hydrocarbons
14.4 Structure of Benzene
15.0 Modern Concept
15.1 Aromaticity in Benzene and Related Systems
15.2 Huckel’s rule or $\left( {{\bf{4n}}{\text{ }} + {\text{ }}{\bf{2}}} \right)\pi $ electron rule
16.0 Properteis
17.0 Mechanism of Electrophilic Substitution Reactions
17.1 Nitration
17.2 Friedel – Craft Alkylation
17.3 Friedel – Craft Acylation
17.4 Reactions of side chains
18.0 Toluene
19.0 Alkenyl Benzene
10.4 Oxidation reactions of alkenes
7.2 Dehydration of Alcohols
7.3 Dehalogenation
7.4 Thermal elimination reaction
7.5 By partial reduction of alkynes:
7.6 Wittig Reaction
7.7 Kolbe hydrocarbon synthesis
10.2 Mechanism of halohydrin formation
10.3 Syn - hydroxylation
10.4 Oxidation reactions of alkenes
12.2 Kolbe’s method
12.3 Dehydrohalogenation of 1, 2 – dihalides
12.4 Dehydrohalogenation of 1, 1 – dihalides
12.5 Dehalogenation of tetrahalides or trihalides
12.6 Alkylation of acetylene and terminal alkynes
14.2 Acidity of Alkynes
14.3 Aromatic Hydrocarbons
14.4 Structure of Benzene
15.2 Huckel’s rule or $\left( {{\bf{4n}}{\text{ }} + {\text{ }}{\bf{2}}} \right)\pi $ electron rule
17.2 Friedel – Craft Alkylation
17.3 Friedel – Craft Acylation
17.4 Reactions of side chains
(i) With cold dilute $KMn{O_4}$ (Baeyer’s reagent) alkenes give 1, 2 – glycols.
\[C{H_3} - CH = C{H_2} + {H_2}O + O\xrightarrow{{}}C{H_3} - CHOH - C{H_2}OH\]
Propene From $KMn{O_4}$ Propylene glycol
(ii) With hot alkaline
Cleavage of C = C bond takes place leading to formation of carboxylic acids, ketones and $C{O_2} + {H_2}O$ depending upon structure of alkene.
Hence by identifying the products formed during alkaline $KMn{O_4}$ oxidation, it is possible to determine the position of the double bond in an alkene molecule.
(iii) With ozone alkenes first give ozonides which upon reductive cleavage with Zn dust and ${H_2}O\,\,or\,\,{H_2}/Pd$ gives aldehydes / ketones or a mixture of these depending upon the structure of alkene.
This two step – conversion of alkene into ozonide followed by decomposition with $Zn/\,{H_2}O$ to give aldehydes / ketones or a mixture of these is called reductive ozonolysis.
If however ozonide is decomposed with ${H_2}O,$ the initially formed aldehydes are further oxidized to the corresponding acids by ${H_2}{O_2}$ produced in the reaction. This is called oxidation ozonolysis.
The oxidation reactions of alkenes are summed up as follows:
