Benzaldehyde & Method of preparation of Benzaldehyde, Assignment Help

Aromatic Carbonyl Compounds - Benzaldehyde & Method of preparation of Benzaldehyde,

Benzaldehyde, C6H5CHO 

          Benzaldehyde is the simplest aromatic aldehyde. It happens in bitter almonds in the form of its glucoside, amygdalin (C20H27O11N). When amygdalin is boiled with dilute acids, it hydrolyses goes into benzaldehyde, HCN nad glucose.

         234_preparation of benzaldehyde.png

         Benzaldehyde is also defined as oil of bitter almonds.

         (1) Method of preparation

         (i) Laboratory method : It is conveniently prepared by boiling benzyl chloride with copper nitrate or lead nitrate solution in a current of carbon dioxide.

1976_preparation of benzaldehyde1.png

         (ii) Rosenmund reaction :

         2378_preparation of benzaldehyde2.png

         (iii) By dry distillation of a mixture of calcium benzoate and calcium formate

         1854_preparation of benzaldehyde3.png

         (iv) By oxidation of benzyl alcohol : This involves the treatment of benzyl alcohol with dil. HNO3 or acidic potassium dichromate or chromic anhydride in acetic anhydride or with copper catalyst at 350o C.


                641_preparation of benzaldehyde4.png                    

This process is used for commercial production of benzaldehyde.

         (v) By oxidation of Toluene

           1610_preparation of benzaldehyde5.png

         Commercially the oxidation of toluene is done with air and diluted with nitrogen (to prevent complete oxidation) at 500o C in the presence of oxides of Mn, Mo  or Zr as catalyst.

         (vi) Etard's reaction344_preparation of benzaldehyde6.png

         (vii) Gattermann-koch aldehyde synthesis : Benzene is converted into benzaldehyde by passing a mixture of carbon monoxide and HCl gas under high pressure into the ether solution of benzene in presence of anhydrous aluminium chloride and cuprous chloride.

                   1234_preparation of benzaldehyde7.png

         (viii) Gattermann reaction

        690_preparation of benzaldehyde8.png

         (ix) Stephen's reaction : Benzaldehyde is obtained by partial reduction of phenyl cyanide with stannous chloride and passing dry HCl gas in ether solution followed by hydrolysis of the aldimine stannic chloride with water.

         (x)  By ozonolysis of styrene

         1885_preparation of benzaldehyde9.png

         (xi) Grignard reaction  

767_preparation of benzaldehyde10.png

         Other reagents like carbon monoxide or HCN can also be used in place of ethyl formate.

 

Email based Chemistry assignment help - homework help at Expertsmind

Are you searching chemistry expert for help with Benzaldehyde questions?  Benzaldehyde topic is not easier to learn without external help?  We at www.expertsmind.com offer finest service of Chemistry assignment help and chemistry homework help. Live tutors are available for 24x7 hours helping students in their Benzaldehyde related problems. We provide step by step Benzaldehyde question's answers with 100% plagiarism free content. We prepare quality content and notes for Benzaldehyde topic under chemistry theory and study material. These are avail for subscribed users and they can get advantages anytime.

Why Expertsmind for assignment help

  1. Higher degree holder and experienced experts network
  2. Punctuality and responsibility of work
  3. Quality solution with 100% plagiarism free answers
  4. Time on Delivery
  5. Privacy of information and details
  6. Excellence in solving chemistry queries in excels and word format.
  7. Best tutoring assistance 24x7 hours