--%>
Assignment Help - homework help

Explain the preparation of phenols.

The methods used for the preparation of phenols are given below:
    
From aryl sulphonic acids

Aryl sulphonic acids on fusion with NaOH at 573 K followed by acidification yield phenols.

1616_Phenol preparation.png 

From aryl halides (Dow's process)

Phenol is obtained on a large scale by heating chlorobenzene with 10% NaOH solution at about 623 K and under a pressure of 300 atmospheres in the presence of copper catalyst.

1327_Phenol preparation1.png 

From diazonium salts

In the laboratory phenols are prepared hydrolysis of diazonium salts with water or dilute acids.

994_Phenol preparation2.png 
    
By decarboxylation of sodium salt of saclicyclic acid

Phenol can also be obtained by the decarboxylation of sodium salicyclate with soda lime (an equimolar mixture of NaOH and CaO).
                           
289_Phenol preparation3.png 
    
From Grignard's reagent

when oxygen is bubbled through the solution of phenylmagnesium bromide in ether, it forms an addition product which on acidification with dilute acid gives phenol.

1498_Phenol preparation4.png

   Related Questions in Chemistry

  • Q : Mole fraction in vapours Choose the

    Choose the right answer from following. If two substances A and B have P0A P0B= 1:2 and have mole fraction in solution 1 : 2 then mole fraction of A in vapours: (a) 0.33 (b) 0.25 (c) 0.52 (d) 0.2

    		•
  • Q : Chem Silicon has three naturally

    Silicon has three naturally occurring isotopes. 28Si, mass = 27.976927; 29Si, mass = 28.976495; 30Si, mass = 29.973770 and 3.10% abundance. What is the abundance of 28Si?

    		•
  • Q : How haloalkanes are prepared from

    Alkyl halides can be prepared from alkanes through substitution and from alkenes through addition of halogen acids or through allylic substitution.    From alkanesWhen alkanes are treated with halogens, chlo

    		•
  • Q : Volume of solution containing solute

    What volume of solution contains 0.1 mole of the solute: (a) 100ml (b) 125ml  (c) 500ml (d) 62.5ml Choose the right answer from above.

    		•
  • Q : Chemistry brief discription of relative

    brief discription of relative lowering of vapour pressure

    		•
  • Q : Lab question Explain how dissolving the

    Explain how dissolving the Group IV carbonate precipitate with 6M CH3COOH, followed by the addition of extra acetic acid, establishes a buffer with a pH of approximately 5.

    		•
  • Q : Explain Solid Compound Formation. In

    In some two component, solid liquid systems, a solid compound forms.In systems in which the components have an interaction for such other, a solid state compound of the two compounds of the two components can form.Formic acid and formaide form a solid state, one-to-one com

    		•
  • Q : Question based on lowering of vapour

    Choose the right answer from following. The relative lowering of vapour pressure produced by dissolving 71.5 g of a substance in 1000 g of water is 0.00713. The molecular weight of the substance will be:  (a) 18.0 (b) 342 (c) 60 (d) 180

    		•
  • Q : How alkyl group reactions takes place?

    Halogenations: ethers react with chlorine and bromine to give substitution products. The extent of halogenations depends upon the conditions of reacti

    		•
  • Q : Molecular weight of solute Select right

    Select right answer of the question. A dry air is passed through the solution, containing the 10 gm of solute and 90 gm of water and then it pass through pure water. There is the depression in weight of solution wt by 2.5 gm and in weight of pure solvent by 0.05 gm. C

    		•