--%>
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 : Which solution will have highest

    Which solution will have highest boiling point:(a) 1% solution of glucose in water  (b) 1% solution of sodium chloride in water  (c) 1% solution of zinc sulphate in water  (d) 1% solution of urea in waterAnswer: (b) Na

    		•
  • Q : Problem on vapour pressure Choose the

    Choose the right answer from following. If P and P are the vapour pressure of a solvent and its solution respectively N1 and N2 and are the mole fractions of the solvent and solute respectively, then correct relation is: (a) P= PoN1 (b) P= Po N2 (c)P0= N2 (d)

    		•
  • Q : Relationship between free energy and

    The free energy of a gas depends on the pressure that confines the gas. The standard free energies of formation, like those allow predictions to be made of the possibility of a reaction at 25°C for each reagent at 

    		•
  • Q : Strength of dilute acid of Sulfuric acid

    Select the right answer of the question.10ml of conc.H2SO4 (18 molar) is diluted to 1 litre. The approximate strength of dilute acid could be: (a)0.18 N (b)0.09 N (c) 0.36 N (d)1800 N

    		•
  • Q : Acid Solutions Choose the right answer

    Choose the right answer from following. Volume of water needed to mix with 10 ml 10N NHO3 to get 0.1 N HNO3: (a) 1000 ml (b) 990 ml (c) 1010 ml (d) 10 ml

    		•
  • Q : Explain Rotational Vibrational Spectra

    The infrared spectrum of gas samples shows the effect of rotational-energy changes along with the vibrational energy change.As we know from the interpretations given to thermodynamic properties of gases, gas molecules are simultaneously rotating and vibrating. It follows that an absor

    		•
  • Q : Molarity of the final mixture Can

    Can someone please help me in getting through this problem. Two solutions of a substance (that is, non electrolyte) are mixed in the given manner 480 ml of 1.5M first solution + 520 ml of 1.2M second solution. Determine the molarity of the final mixture

    		•
  • Q : Determining of normality of sodium

    Can someone please help me in getting through this problem. The normality of a solution of sodium hydroxide 100 ml of which includes 4 grams of NaOH is: (a) 0.1 (b) 40 (c) 1.0 (d) 0.4

    		•
  • Q : Lowering of vapour pressure Help me to

    Help me to go through this problem. Lowering of vapour pressure is highest for: (a) urea (b) 0.1 M glucose (c) 0.1M MgSo4 (d) 0.1M BaCl2

    		•
  • Q : Symmetry Elements The symmetry of the

    The symmetry of the molecules can be described in terms of electrons of symmetry and the corresponding symmetry operations.Clearly some molecules, like H2O and CH4, are symmetric. Now w

    		•