Oxidation of 1°, 2° and 3° alcohols1°, 2° और 3° ऐल्कोहॉल का ऑक्सीकरणOxidation of 1°, 2° and 3° alcohols
Class 12 Chemistry · Chapter 7 · interactive diagram
Parts and what they mean
- Primary alcohol → aldehyde → carboxylic acid (प्राथमिक ऐल्कोहॉल → ऐल्डिहाइड → कार्बोक्सिलिक अम्ल) — Oxidation forms C=O by breaking an O–H and a C–H bond (a dehydrogenation).
- CrO₃ in anhydrous medium: stops at the aldehyde (निर्जल माध्यम में CrO₃: ऐल्डिहाइड पर रुकता है) — Used for isolating aldehydes from 1° alcohols.
- PCC (pyridinium chlorochromate): a better reagent for aldehydes (PCC (पिरिडिनियम क्लोरोक्रोमेट): ऐल्डिहाइड के लिए बेहतर अभिकर्मक) — PCC is a complex of chromium trioxide with pyridine and HCl; the C=C stays untouched (but-2-en-1-ol → but-2-enal).
- Acidified KMnO₄: strong oxidant → carboxylic acid directly (अम्लीकृत KMnO₄: प्रबल ऑक्सीकारक → सीधे कार्बोक्सिलिक अम्ल) — Strong oxidising agents give acids directly from 1° alcohols.
- Secondary alcohol → ketone (chromic anhydride, CrO₃) (द्वितीयक ऐल्कोहॉल → कीटोन (क्रोमिक ऐनहाइड्राइड, CrO₃)) — The ketone is not oxidised further under these conditions.
- Tertiary alcohol: no oxidation (तृतीयक ऐल्कोहॉल: ऑक्सीकरण नहीं) — Strong agents (KMnO₄) at elevated temperature break C–C bonds and give a mixture of acids with fewer carbon atoms.
- Heated copper at 573 K (573 K पर गर्म कॉपर) — 1° → aldehyde, 2° → ketone (dehydrogenation); 3° alcohols undergo dehydration to alkenes.
Original diagram drawn by Simple Learning Hub, based on the NCERT textbook. Report a mistake