Alcohols and Phenols

Subject: Chemistry

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  • Skill Level Medium



Alcohol and its types.

Alcohols are hydroxyl derivative of alkanes containing –OH as a functional group.These compounds are obtained from alkanes replacing hydrogen atom by a hydroxyl group.An alcohol containing two -OH group is called dihydric alcohol. Learn More

Isomerism of Alcohol

Alcohols exhibits following three types of isomerism. They are Chain isomerism.Position isomerism. Functional isomerism.In the common system of nomenclature,alcohols are named as. $$Alkyl\,+alcohol=Alkyl\,alcohol$$ Structural formula of tertiary butanol is given below and its IUPAC name is 2.methyl propane-2ol Learn More

General method of preparation of Alcohol

Haloalkane reacts with aueous alkali or moist AgO to give corresponding alcohols. $$\underbrace{R-H}_{halo\,Alkane}\xrightarrow{aq.alkali\,or\,moist\,Ag_2O}\underbrace{R-OH}_{Alcohol}$$ Aldehydes and ketones from addition product with Grignard reagent. These addition products of hydrolysis in presence of an acid give alcohols. All three types of alcohol )10, 20, and 30) can be prepared by this method.Primary amines react with nitrous acid to give corresponding alcohol. $$\underbrace{R-NH_2}_{Primary\,amine}+HO-NO→\underbrace{R-OH}_{Alcohol}+N_2+H_2O$$ Learn More

Industrial method of preparation of alcohol

There are three methods to get alcohols, industrially. all these methods utilise raw materials which can be obtained from petroleum, natural gas, coal and biomass. The methods are outlined below.By hydration of alkenes. By oxo process. By fermentation of carbohydrates. Learn More

Victor Meyers method of distinguish Primary,Secondary and Tertiary alcohol

Victor Mayer method is one of the most important methods of identification of alcohols. In this methods primary,secondary and tertiary alcohols are subjected to a series of chemical analysis and the colour of resulting solution is observed. A primary alcohol gives blood red colour. secondary alcohol gives the blue colour. A tertiary alcohol does not produce any colour. Learn More

Chemical property of Alcohol

The presence of electrons donating group (+I groups) decreases the acidic strength of alcohol. Therefore, alcohols are less acidic than water. $$\underbrace{H-O-H}_{water}$$ $$\underbrace{R-O-H}_{Alcohol}$$ Similarly, acidic strength decreases gradually on moving from primary to secondary to tertiary alcohol. $$R-CH_2-OH>R_2CH-OH>R_3-C-OH$$ Esterification Alcohols react with carboxylic acids in presence of small amount of conc. H2SO4 to produce sweet smelling compound called esters. Thereaction is known as esterification. $$\underbrace{R-COOH}_{Carboxylic\,acid}+\underbrace{R-OH}_{alcohol}\xrightarrow{Conc.H_2SO_4}\underbrace{R-COOR}_{Ester}+H_2O$$ Learn More

Other reaction of Alcohol

$$\underbrace{CH_3-CH_2-OH}_{Ethanol}\xrightarrow{Conc-H_2SO_4\,160^0-170^0C}\underbrace{CH_2=CH_2}_{Ethene}+H_2O$$ $$\underbrace{CH_3-CHOH-CH_3}_{2-Propanol}\xrightarrow{Conc-H_2SO_4\,160^0-170^0C}\underbrace{CH_2=CH-CH_3}_{Propene}$$ $$\underbrace{CH_3-CH_2-CHOH-CH_3}_{2-butanol}\xrightarrow{Conc-H_2SO_4\,160^0-170^0C}\underbrace{CH_3-CH=CH-CH_3}_{2-butene}+H_2O$$ A primary alcohol is easily oxidised to an aldehyde which gets further oxidised to give a carboxylic acid containing carbon atoms equal to that of alcohols. Tertiary alcohol are not oxidised by neutral or alkaline oxidising agents but acidic oxidising oxidise them. At first, the alkene is formed due to dehydration which is then oxidised to give a mixture of aldehydes, ketones and acids. Learn More

Physical property of alcohol

Alcohol can form the hydrogen bond with the water molecule. Therefore, they are soluble in polar solvents like water. Their solubility , however, decreases with increase in a size of an alkyl group.Ethene is oxidised in the air in presence of catalyst and temperature to produce epoxy ethane which on acid hydrolysis gives ethylene glycol.Fats and oils are the esters of long chain fatty acids known as triglycerides. These esters can be hydrolyzed both in acidic and basic medium to manufacture glycerol. Alkali hydrolysis of these esters produces glycerol and soap. This process is known as saponification. Learn More

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. Learn More

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. Learn More

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. Learn More

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. Learn More

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