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Question
Account for the following :
t-butyl chloride on heating with sodium methoxide gives 2-methylpropene instead of t-butyl methyl ether.
Solution
Sodium methoxide is a strong base hence elimination predominates over substitution
\[\begin{array}{cc}
\ce{CH3}\phantom{.............................}\\
|\phantom{...............................}\\
\ce{CH3-C-Cl +CH3O^-Na^+->CH3-C=CH3OH + NaCI}\\
|\phantom{...............................}||\\
\phantom{....}\ce{CH3}\phantom{..............}\phantom{..............}\ce{CH2}
\end{array}\]
William synthesis
\[\ce{R - X + R -\underset{\bullet\bullet}{{}^{\bullet\bullet}_{O}} - Na->R - \underset{\bullet\bullet}{{}^{\bullet\bullet}_{O}} - R + NaX}\]
The alkyl halide must be 1⁰ as the reaction involves the SN2 reaction pathway.
If alkyl halide is 3⁰ then the alkene will be the major product. Hence, 2-methylpropene is formed instead of t-butylmethylether.
RELATED QUESTIONS
Write the name of the reagent and the equation for the preparation of the following ether by Williamson’s synthesis:
2-Methoxy-2-methylpropane
Preparation of ethers by acid dehydration of secondary or tertiary alcohols is not a suitable method. Give reason.
Explain the following with an example.
Williamson ether synthesis
Dehydration of alcohol to ethers is catalysed by:
\[\ce{(CH3)3CONa + CH3CH2Cl ->[-NaCl] (CH3)3COC2H5}\] is called:
Identify the following named reaction
\[\ce{C2H5Br ->[NaOCH3] C2H5OCH3}\]
Write the name of the reaction, structure and IUPAC name of the product formed when:
\[\ce{CH3CH2CH(CH3)CH(CH3) ONa}\] reacts with \[\ce{C2H5Br}\]
Write the names of reagents and equations for the preparation of the following ether by Williamson’s synthesis:
2-Methoxy-2-methylpropane
Short Answer Question.
Identify the product (s) is/are formed when 1 – methoxy propane is heated with excess HI. Name the mechanism involved in the reaction.
Write the name of reagent and equation for the preparation of the following ether by Williamson’s synthesis:
2-Methoxy-2-methylpropane
