Estimation of methoxy group

1. METHOXYL GROUP
BY
V.SRINANDAN
M.PHARMACY
1ST YEAR
DEPT. OF PHARM. ANALYSIS

2. INTRODUCTION
 Methoxy consisting of a methyl
group bound to oxygen.
Alkoxy group has the formula O–CH3
Used to describe an ether.
Electron-donating group.

3. Methoxy compounds are
Di methyl ether
Anisole Vanillin

4. Estimation of the number of Methoxy group
by Zeisel’s Method
Reaction B/W ether and Hydroiodic acid used
R –OCH3 +HI→ R-OH + H3C-I
Methoxy liberated is absorbed in alc.Silver nitrate soln and silver
iodide is ppted.
CH3I + AgNO3 + H2O → CH3OH + AgI↓ + HNO3
One Mole Of Silver Iodide Precipitate Corresponds To Presence
Of One Methoxy Group

5. Calculation
Wt of sample taken = w1 gms
Wt of AgI formed = w2 gms
From above reaction
1 mole of AgI = one OCH3 group
234g of AgI = 31g of OCH3 group
Percentage of methoxy group = 31/234 * w2/w1 * 100

6. PREPARATION OF ETHER
DEHYDRATION OF ALCOHOLS

7. WILLIAMSON ETHER SYNTHESIS

8. C2H5ONa + C2H5Br C2H5-O-C2H5 + NaBr
Sod.eth
oxide
Bromo
ethane
Di Ethyl Ether