EasyChemistryHigh School (11–12)Organic Compounds with Functional Groups › Aldehydes, Ketones and Carboxylic AcidsConceptualA-LevelIB
Name the reagent and the product for each change of propanoic acid…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
Name the reagent and the product for each change of propanoic acid.
- to propanoyl chloride
- to propan-1-ol
- to ethyl propanoate
- to 2-bromopropanoic acid
- the sodium salt, heated with soda lime, to an alkane
Need a reminder? The key ideaShow
Fischer esterification is an equilibrium: for 1 mol of acid and mol of alcohol. SOCl gives acid chlorides, LiAlH gives alcohols, Br with red P gives 2-bromo acids (Hell-Volhard-Zelinsky), soda lime removes one carbon, and Kolbe electrolysis doubles the alkyl group. Molar volume of a gas at 273 K and 1 atm: 22.4 L/mol.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. Thionyl chloride, : propanoyl chloride, with sulphur dioxide and hydrogen chloride.
Step 2. Lithium aluminium hydride in dry ether, then dilute acid: propan-1-ol.
Step 3. Ethanol with a little concentrated sulphuric acid and heat: ethyl propanoate.
Step 4. Bromine and a little red phosphorus (Hell-Volhard-Zelinsky): 2-bromopropanoic acid.
Step 5. Soda lime and heat: ethane, one carbon fewer.
Check. Only the last reaction changes the number of carbons.
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