Chemical Properties f Diethyl Ether Preparation and Properties
Ethoxy ethane CH3—CH2—O—CH2—CH3 gives the following four types of reactions:
- Substitution reactions of ethyl group.
- Reactions due to the presence of lone pairs of electron on oxygen atom of ether functional group.
- Reactions involving Cleavage of C—O bond.
Other reactions :
Substitution Reactions of Ethyl Group
→ Halogenatlon : When diethyl ether is heated with chlorine or bromine, then hydrogen atom present on α-Carbon of ether gets substituted by halogen atoms.
→ Halogenation in Dark
→ Halogenation in the Presence of Sunlight : Ethoxy ethane reacts with chlorine in the presence of sunlight to form per chiorodiethyl ether.
→ ReactIons Due to the Presence of Lone Pairs of Electrons on Oxygen Atom of Ether Functional Group
→ Formation of Peroxide : Diethyl ether reacts with oxygen from air or ozone to form peroxides.
→ If ether is left for long time in air then its self oxidation occurs and 1-ethoxy ethyl hydro peroxide forms which is explosive in nature.
→ Formation of Oxonium Salt : Ethers acts as Bronsted Lowry base with inorganic acids and forms oxonium salt. For example when diethyl ether is heated with conc. sulphuric acid firstly oxonium salt forms which finally converts into ethyl hydrogen sulphate.
→ With HCl gas diethyl ether forms oxonium salt also.
→ Ether act as Lewis base with electron deficient compounds and form oxonium salt.
→ Reaction Involving Cleavage of C—O Bond
→ Reaction with hydrogen halide (HX) : When ether reacts with hydrogen halide then alkyl halide and alcohol are formed.
C2H5OC2H5 + HX → C2H5—OH + C2H5—X
C2H5—O—C2H5 + HI → C2H5—OH + C2H5—I
→ When excess of hydrogen halide is taken then alkyl halide and water are formed as end product:
R—O—R + HX → RX + R — O —H
R—OH + HX — RX + H2O
The order of reactivity of Halogen acids is
HI > HBr > HCl
→ Zeisel Method : Use of reaction of methyl ether with HI is done in the quantitative analysis of methoxy groups. This method is known as Zeisel method.
→ When reaction of mixed ether is carried out with hydrogen halide, then according to the nature of alkyl group (Pri mary/Secondary/Tertiary) different products are formed.
→ If in mixed ether one alkyl group is primary and second group is tertiary alkyl group, then alcohol of primary group and halide of tertiary alkyl group are formed and reaction occurs through SN1 mechanism.
→ If Alkyl groups attached to mixed ether are primary and secondary then primary and small alkyl group form halide and reaction occurs through SN2 mechanism.
→ If one akyl group is tertiary then alkyl halide forms by tertiary alkyl group.
→ HydrolysIs : When ether is heated with dii. H2SO4 at high pressure, then ethanol forms.
→ Reduction : When diethyl ether is reduced in liquid Ammonia with Na, alkane and alkanol are formed.
→ When heated with red phosphorus and HI ethane forms.
→ Reaction with Acetyl Chloride : When ether reacts with acetyl chloride in the presence of anhydrous ZnCl2, ethyl acetate and ethyl chloride forms.
→ Reaction with Acetic Anthydride When ether is heated with acetic anhydride in the presence of anhydrous ZnCl2, ethyl acetate forms.
→ Dehydration : When vapours of diethyl ether are passed over alumina at 653 K temperature, water molecule eliminates and ethene forms.
→ Reaction with Carbon Monoxide: Ether forms ester with CO in the presence of BF3 catalyst and water at 500 atm pressure and 398-423 K tempeature.
→ Combustion : Diethyl ether burns in air with flame containing 1iht to form water and carbon dioxide.
C2H5 — O — C2H5 + 6O2 → 4CO2 + 5H2O