|
They are denoted by :
For example:
2) Classification of Ether: A) Simple or Symmetrical ether: It is defined as the ether which has identical groups across "O' atom. For example:
B) Mixed or Unsymmetrical ether: It is defined as the ether which has different groups across "O' atom. For example:
3) Isomerism Alcohol and Ether have the same general formula so they are functional isomers. Some of the possible isomers for the common molecular formula are given below:
4) General methods Of Preparation Of Ether: A) By dehydration of alcohol: When alcohol is heated with concentrated sulphuric acid at 140°, ether is formed via intermolecular dehydration.
B) By Williamson's synthesis: When haloalkane is heated with sodium alkoxide, ether is formed This reaction is called Williamson's synthesis.
It is important in the preparation of unsymmetrical ether. 5) Lab Preparation Of Ether/ Diethyl ether/ Ethoxyethane: Principle:
In
lab ether is prepared by heating ethanol with concentrated sulphuric acid at 140°C.
Temperature shouldn’t
exceed 140°C while lab preparation of ether as ethene forms
at 160-170°C.
Procedure:
Ethanol
and Concentrated sulphuric acid is taken in 2:1 ration in the round bottom flask.
Then this mixture is heated over a sand bath at 140°C. As a result, ether starts to form that passes
through eater condenser. Thus formed ether is collected in the receiver held in a water bath with ice cubes. As soon as ether starts to form ethanol is added to
R.B flask through thistle funnel for continuous etherification. The resultant
mixture is transferred to separating funnel to separate ether from the aqueous
layer. Then ether is subjected to purification. Purification: 1. Ether is washed with NaOH solution to
remove the acidic layer. 2. Ether then is washed with water
several times to remove water-soluble impurities. 3. Then, alcohol present it, is removed
with a 50% Calcium chloride solution. 4. Then ether is dried over anhydrous Calcium chloride.
5. Finally, pure and dry ether is obtained by
distillation at 32°C-35°
6) Physical Properties: A) Solubility: Lower members of the ether is water-soluble. This is because it can form intermolecular H-bonding with water molecules as it has a strong electronegative "O" atom.
B) Boiling Point: Ether boils at a lower temperature in comparison to alcohol of comparable molecular mass as it doesn't contain OH so there is no intermolecular H-bonding.
7) Chemical Properties: A) Reaction due to Unshared pair of an electron: i) Reaction with conc. and cold HCl: When ether is treated with conc. and cold HCl, Dialkyl oxonium chloride salt is formed.
ii) Reaction with air: When ether is treated with air in the presence of sunlight, dialkyl peroxide is formed which is an explosive compound at high temperature.
B) Reaction due to CO group i) Reaction with Phosphorous Pentachloride With Phosphorous Pentachloride, ether forms Chloroalkane.
ii) Reaction with sulphuric acid: a) With dilute sulphuric acid: When ether is heated with dilute sulphuric acid, alcohol is formed.
b) With conc. sulphuric acid: When ether is heated with concentrated sulphuric acid, alcohol and alkyl hydrogen sulphate is formed.
c) With excess sulphuric acid: When ether is heated with excess sulphuric acid, alkyl hydrogen sulphate is formed.
iii) Reaction with HX (HCl/ HBr): a) With conc. HX (HCl/ HBr):
When ether is treated with conc. HX (HCl/ HBr), alcohol and corresponding haloalkane is formed.
b) With excess HX (HCl/ HBr):
When ether is treated with excess HX (HCl/ HBr), the corresponding haloalkane is formed.
C) Reaction due to 𝛂-Hydrogen
i) Reaction with Chlorine at dark When ethoxyethane is treated with chlorine at dark, 𝛂,𝛂'-dichloro diethyl ether is formed. ii) Reaction with Chlorine in light: When ethoxyethane is treated with chlorine in the presence of sunlight, perchloro diethyl ether is formed.
8) Uses 1. Ether is used as a solvent to dissolve
gums, resin, etc. 2. Dimethyl ether is used as a refrigerant. 3. Diethyl ether is used as anesthesia.
CLICK THE DOWNLOAD BUTTON TO ACCESS THE GIVE MATERIAL.
 | THANK YOU VERY VERY MUCH
|
|
ConversionConversion EmoticonEmoticon