Alkali Medium (organic chem)


I originally wanted to kickstart this post with a picture of NaOH, but none of the pictures on the web were appetizing so searching KOH brought me to Koh Samui and so yeah…

Alright! Alkali is used very often in organic chemistry as part of reagents and conditions because it can act as a CATALYST.

common reactions requiring Alkali here

1) ALKALINE hydrolysis of RX  to give ROH

2) catalyse TOLLEN reagent, FEHLING solution and IODINE oxidising reactions!

3) catalyse the esterification process between Acyl Chloride and Phenol! take note that

*only Acyl Chloride can form ester with Phenol

*unlike staight-chain alcohol, for phenol to form ester require ALKALI catalyst

3) Interchangeable with acid :

– hydrolysis of CN to COOH, (if alkali hydrolysis, COOH -> COO-)

– Catalyse KMnO4, K2Cr2O7 oxidation rxns with Primary and Secondary ALCOHOLS and ALDEHYDES

+ NOTES +

If Alkali is used With  OXIDISING AGENTS (Fehling, Tollen, Iodine, K2Cr2O7, KMnO4)  as catalyst…

And the product of oxidation is RCOOH….

remember that RCOOH will undergo acid base reaction with the Alkali Catalyst

to give you RCOO-

Then if you need to get RCOOH to further react to form Acyl Chloride, Primary Alcohol ETC

you will need to first ACIDIFY RCOO-

this step involves the use of any dilute acid like H2SO4 (aq)

and merely changes RCOO- to RCOOH

but is worth marks in exam!!!

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