--%>
Assignment Help - homework help

Explain methods for industrial preparation of alcohol.

The important methods for the preparation of alcohol on large-scale are given below:
    
By hydration of Alkenes

Alkenes are obtained by cracking of petroleum. They are easily converted to alcohols by the addition of water in presence of sulphuric acid.
                                 
1907_alcohol preparation.png 

In case of unsymmetrical alkenes, the addition takes place according to Markowniko's rule.
                          
681_alcohol preparation1.png 
    
By fermentation of carbohydrates

Formation of ethyl alcohol by the fermentation of sugar (obtained from molasses, grapes or beet) is one of the oldest methods. Sucrose is first of all changed to glucose and fructose with an enzyme invertase.
                                
1330_alcohol preparation2.png 

Enzyme zymase after that converts glucose and fructose into ethanol.

The enzyme zymase is present in yeast.
                              
65_alcohol preparation3.png 

The fermentation procedure is taken out under anaerobic conditions i.e. in the nonexistence of air. Carbon dioxide released during fermentation keeps the fermentation mixture out of contact of air. If the fermentation mixture gets exposed to air, the oxygen of air oxidizes ethanol to ethanoic acid which makes the mixture sour.

Ethanol is obtained from starchy materials such as barley, rice, maize and potatoes with enzymes diastase and maltase.
                        
1057_alcohol preparation4.png 

Enzyme diastase is obtained from germinated barley while enzyme maltase and zymase are obtained from yeast.
    
Oxo process

Alkenes react with carbon monoxide and hydrogen in the presence of Octacarbonyl dicobalt Co[CO]
                       
1121_alcohol preparation5.png

   Related Questions in Chemistry

  • Q : Molar mass of compound The freezing

    The freezing point of a solution having 4.8 g of a compound in 60 g of benzene is 4.48. Determine the molar mass of the compound (Kf = 5.1 Km-1) , (freezing point of  benzene = 5.5oC)          &n

    		•
  • Q : Finding Molarity of final mixture Can

    Can someone help me in finding out the right answer. 25ml of 3.0 MHNO3 are mixed with 75ml of 4.0 MHNO3. If the volumes are adding up the molarnity of the final mixture would be: (a) 3.25M (b) 4.0M (c) 3.75M (d) 3.50M

    		•
  • Q : Short note on the function of

    Write down a short note on the function of mitochondria?

    		•
  • Q : Molecular Symmetry Types The number of

    The number of molecular orbitals and molecular motions of each symmetry type can be deduced. Let us continue to use the C2v point group and the H2O molecule to illustrate how the procedure develop

    		•
  • Q : Problem based on mole concept Choose

    Choose the right answer from following. An aqueous solution of glucose is 10% in strength. The volume in which mole of it is dissolved will be : (a) 18 litre (b) 9 litre (c) 0.9 litre (d) 1.8 litre

    		•
  • Q : Crystals of covalent compounds Crystals

    Crystals of the covalent compounds always contain:(i) Atoms as their structural units  (ii) Molecules as structural units  (iii) Ions held altogether by electrostatic forces (iv) High melting pointsAnswer: (i)

    		•
  • Q : Dipole moment direction for the methanol

    Briefly describe the dipole moment direction for the methanol?

    		•
  • Q : Problem on endothermic or exothermic At

    At low temperatures, mixtures of water and methane can form a hydrate (i.e. a solid containing trapped methane). Hydrates are potentially a very large source of underground trapped methane in the pole regions but are a nuisance when they form in pipelines and block th

    		•
  • Q : Illustrate the Lewis Dot Structure

    Illustrate the Lewis Dot Structure for the CH4O.

    		•
  • Q : Dipole moment of chloro-octane Describe

    Describe the dipole moment of chloro-octane in brief?

    		•