preparations of phenols.pptx their intro

Introduction and Preparation of phenols ;
INTRODUCTION:
Discovery
Definition
A versatile Organic Compound

PREPARATIONS OF PHENOLS:
.Hydrolysis of Chlorobenzene
..Alkali fusion of Sodium .Benzenesulphate
.Oxidation of cumene
.Hydrolysis of .Benzenediazonium salts
Some naturly occuring phenols are also present. Discovery:
Phenol was discovered in 1834 by Runge, who extracted it (in impure form) from coal tar. Runge called phenol.
Definition:
In organic chemistry, phenols, sometimes called phenolics, are a class of chemical compounds consisting of one or more hydroxyl groups (−O H) bonded directly to an aromatic hydrocarbon group. The simplest is phenol, C. 6H. 5. OH.
Phenol is also a versatile precursor to a large collection of drugs, most notably aspirin but also many herbicides and pharmaceutical drugs.
Hydrolysis of Chlorobenzene:
In this process, the chlorobenzene which can be obtained by the chlorination of benzen,is heated at 350˚C under high pressure with aqueous sodium hydroxide to get sodium phenoxide , which on acidification yields phenol.
Alkali fusion of Sodium Benzenesulphate
This, the first commercial process for industrial systhesizing phenol,was developed in Germany in1890. Sodium benezensulphonate is melted (fuesd) with sodium hydroxide at 350˚C to produce sodium phenoxide , which on acidification yields phenol .It involves the sulphonation of benzen.
Oxidation of cumene:
(Isopropylbenzene).Benzene is alkylated with propane to produce cumene ,which is oxidized with air to produce cumene hydroperoxide,which on tretment with 10% H2SO4 undergoes a hydrolytic rearangment to yield phenol and acetone.
Hydrolysis of Benzenediazonium salts:
Aqueous solution of benzendiazonium salt, obtained by the raction of aniline with nitrous acid at 0 C, on boiling with water loses nitrogen to produce phenol. Nitrous acid at 0 C,when needed. The aniline is obtained from benzen through nitration followed by reduction.
Hydrolysis of Benzenediazonium salts:
Aqueous solution of benzendiazonium salt, obtained by the raction of aniline with nitrous acid at 0 C, on boiling with water loses nitrogen to produce phenol. Nitrous acid at 0 C,when needed. The aniline is obtained from benzen through nitration followed by reduction.
Oxidation of cumene:
(Isopropylbenzene).Benzene is alkylated with propane to produce cumene ,which is oxidized with air to produce cumene hydroperoxide,which on tretment with 10% H2SO4 undergoes a hydrolytic rearangment to yield phenol and acetone.
Methyl phenols can be obtain by the refining of heavy oil and middle oil of col tar . O- isomer (b.p 191°c) is separated from m-isomer (b.p201°c) by frictional distillation each isomer may be obtained in its pure form from the corresponding toluidine
Methyl phenols can be obtain by the refining of heavy oil and middle oil of col ta

1. Phenols Intro and Preparations HIBA KALSOOM

2. Outline INTRO Discovery Definition A versatile Organic Compound PREPARATIONS Hydrolysis of Chlorobenzene Alkali fusion of Sodium Benzenesulphate Oxidation of cumene Hydrolysis of Benzenediazonium salts

3. INTRO Discovery: Phenol was discovered in 1834 by Runge , who extracted it (in impure form) from coal tar. Runge called phenol. Definition: In organic chemistry, phenols, sometimes called phenolics , are a class of chemical compounds consisting of one or more hydroxyl groups (−O H) bonded directly to an aromatic hydrocarbon group. The simplest is phenol, C.  6 H.  5 . OH. Phenol is also a versatile precursor to a large collection of drugs, most notably aspirin but also many herbicides and pharmaceutical drugs.

4. Preparation Hydrolysis of Chlorobenzene : In this process, the chlorobenzene which can be obtained by the chlorination of benzen,is heated at 350˚C under high pressure with aqueous sodium hydroxide to get sodium phenoxide , which on acidification yields phenol.

5. Con….. Alkali fusion of Sodium Benzenesulphate This, the first commercial process for industrial systhesizing phenol,was developed in Germany in1890. Sodium benezensulphonate is melted ( fuesd ) with sodium hydroxide at 350˚C to produce sodium phenoxide , which on acidification yields phenol .It involves the sulphonation of benzen .

6. Con……… Oxidation of cumene : ( Isopropylbenzene ).Benzene is alkylated with propane to produce cumene ,which is oxidized with air to produce cumene hydroperoxide,which on tretment with 10% H2SO4 undergoes a hydrolytic rearangment to yield phenol and acetone.

7. Con……. Hydrolysis of Benzenediazonium salts: Aqueous solution of benzendiazonium salt, obtained by the raction of aniline with nitrous acid at 0 C, on boiling with water loses nitrogen to produce phenol. Nitrous acid at 0 C,when needed. The aniline is obtained from benzen through nitration followed by reduction.