Question

write reaction for oxidation of propanol with excess oxidant in two steps

Answer 1

Propanol is a primary alcohol ,Primary alcohols can be oxidised to either aldehydes or carboxylic acids depending on the reaction conditions. In the case of the formation of carboxylic acids, the alcohol is first oxidised to an aldehyde which is then oxidised further to the acid.

1) if you want aldehyde use an excess of the alcohol, and distil off the aldehyde as soon as it forms

2) if you need carboxylic acid use an excess of oxidant ( make sure that, the aldehydes formed in the halfway of  reaction should stay in the reaction mixture, so the reaction should carried out in reflux condition )

3) Normal  Oxidising used for the reaction

K2Cr2O7  Potassium dichromate OR sodium dichromate Na2Cr2O7

‎CrO3   Chromium trioxide

Both of these are used along with Sulfuric acid H2SO4 and water H2O

REACTIONS

( K2Cr2O7/ Na2Cr2O7)

CH3-CH2-CH2-OH + [O]    ------------------------------->  CH3CH2CH=O + H2O (oxygen is from oxidising agent)

( K2Cr2O7/ Na2Cr2O7)

CH3CH2CH=O + [O] -------------------------------> CH3CH2COOH +  H2O

propanoic acid is final product

The full equation for the oxidation of ethanol to ethanoic acid is:

зсH3CH2OH + 2Cr2072- + 16H+ » зснэсоон + 4Cr3+ + 11Н20
  

The full equation for aldehyde

зсH3CH2OH + Cr2O32- + 8H+ + 3CH3сно + 2Cr3+ + 7H20