Notes on lesson on Alcohols and Phenols |

Alcohols and Phenols


Phenol and Nomenclature of Phenol

` Phenols are hydroxy derivatives of benzene obtained by replacing one of the hydrogens of benzene by a hydroxy group. They are represented by general formula Ar-OH, where Ar is phenyl,substituted phenyl or some other aryl group (eg, naphthyl,phenanthryl, etc.Phenols are generally named as derivatives of the simplest member of the family,i,e phenol. In the case of phenols having only one additional substituent, the relative position is usually indicated by letters o-(for 1,2-) m- (for(1,3-) and P-for (1,4-). However, numerals are used if more than two substituents are present on the ring.

Method Of Preparation of Phenol

Most of the industrial methods used for preparing phenols are same as used in the laboratory. However, certain phenols(including the most important one, Phenol) are produced commercially by some special methods which are quite inconvenient to use as laboratory method.Several methods have been used to synthesised phenols commercially. Some important methods for the commercial production are described as above.

Physical property of phenol.

The presence of -OH group in phenol permits the formation of intermolecular H-bond with water molecule whereas hydrophobic phenyl group tends to decrease the solubility. The net results are that phenol is slightly soluble in water.n O-nitro phenol, intramolecular H- bond is formed between H of -OH group and O of an NO2 group as shown but in P-nitro phenol, no intermolecular H-bond is formed. So, in P-nitrophenol intermolecular h bond is formed which increase its boiling point.

Properties, uses tests of ethanol or ethyl alcohol.

Ethanol is the most important and the earliest representative of the class and is popularly referred to as simply alcohol. It is the exhilarating principle of all wines and is thus named as spirits of wines. technically, it is known as grain alcohol since it often manufactured from starchy grains.It also dissolves inorganic substances like caustic soda, caustic potash, sulphur, phosphorous etc. When taken orally in small dosages,alcohol is the good stimulant. The alcohol obtained from the fractional distillation of the fermented liquor contains about 95% of ethanol and is called industrial alcohol. It is also known as rectified spirit and is used for industrial purposes.