The document discusses methoxy groups, which consist of a methyl group bound to oxygen. It provides examples of methoxy compounds like dimethyl ether and anisole. It then describes Zeisel's method for estimating the number of methoxy groups in a compound, which involves reaction with hydroiodic acid to liberate the methoxy group as methyl iodide, which precipitates as silver iodide upon reaction with silver nitrate. The amount of silver iodide precipitate corresponds to the number of methoxy groups present. It also briefly discusses the preparation of ethers through dehydration of alcohols and the Williamson ether synthesis reaction.

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