Ethanol to Butanol | Alcohol to Aldehyde Oxidation by PCC

Derive butanol by starting with Ethanol. You can only use ethanol as a organic compound.

Ethanol is a famous organic compound which is used to synthesis more organic compounds. There are four carbon atoms in butanol molecule. Both ethanol and butanol are alcohol compounds. When we prepare butanol from ethanol, we have to double the number of carbon atoms.


  • Ethanol - CH3CH2OH
  • Butanol - CH3CH2CH2CH2OH

Identify butanol structure

butanol
  • Butanol has four carbon atoms.
  • Therefore, we have to do some carbon chain extending reactions ( such as aldol condensation, grignard reactions, or reaction of alkynes of sodium salt and alkyl halide) to prepare butanol from ethanol.

Preparing butanol from ethanol using aldol condensation

Now, we study the conversion step by step by mentioning all the reagents, reactions and physical conditions.

  • Primary alcohol to aldehyde oxidation
  • Aldol condensation of aldehyde

Alcohol to aldehyde oxidation reaction by PCC - Mild oxidation

Primary alcohols can be oxidized to aldehydes by PCC which is mild oxidizing agent. If we use strong oxidizing agent such as H+ / KMnO4 instead of PCC, we cannot prepare aldehyde from alcohol.


PCC - Pyridinium chlorochromate

Pyridinium chlorochromate is a yellow-orange salt which is used to oxidize alcohols to carbonyl compounds (aldehyde and ketone).


Ethanol and PCC reaction

Ethanol and PCC react to give ethanal (aldehyde). Ethanal's chemical formula is CH3CHO.




Aldol condensation of aldehyde

When aldehyde compound is treated with dilute NaOH or KOH, aldol product is given. This reaction is called as aldol condensation.


Ethanal aldol condensation

Ethanal and dilute NaOH or KOH react with heating to form aldol product. Then given product has four carbon atoms.


Aldehyde reduction to alcohol by hydrogen gas in the presence of nickel catalyst

Aldehyde is reduced to primary alcohols by hydrogen gas in the presence of nickel catalyst. (H2 / Ni.

Instead of H2/ Ni, following reagents also can be used to reduce aldehyde group to alcohol group.

  • LiAlH4 / ether
  • NaBH4
  • Na/ CH3CH2OH

Aldehyde and H2/ Ni

With H2/ Ni, alkene group(double bond) becomes into alkane group and aldehyde group becomes to a alcoholic group.



Preparing butanol from ethanol

ethanol to butanol organic conversion


Questions


How PCC is prepared?

First CrO3 is dissolved in HCl. Then Pyridene is treated with that CrO3 ? HCl in CH2Cl2 medium.



Learn more ethanol and butanol