Is a carboxylic acid group electron donating or election withdrawing and then decide if such a group substituted onto an alkene would be a better candidate for cationic or anionic initiated polymerization?
To determine whether a carboxylic acid group is electron-donating or electron-withdrawing, we need to look at the nature of the substituent on the carboxylic acid group.
A carboxylic acid consists of a carbonyl group (C=O) and a hydroxyl group (-OH) attached to the same carbon atom. The carbonyl group is polar, with oxygen being more electronegative than carbon. As a result, the carbonyl group is electron-withdrawing, meaning it withdraws electron density through inductive and resonance effects.
However, the presence of the hydroxyl group (-OH) in the carboxylic acid can donate electron density through the inductive effect. The hydroxyl group is electron-donating due to the electronegativity difference between oxygen and hydrogen.
Overall, the carboxylic acid group is slightly electron-withdrawing but can also exhibit some electron-donating characteristics.
Now, let's discuss whether a carboxylic acid group substituted onto an alkene would be a better candidate for cationic or anionic initiated polymerization.
During cationic polymerization, a cationic initiator generates a carbocation, which acts as an electrophile, initiating the polymerization process. In this case, the electron-withdrawing nature of the carboxylic acid group can stabilize the carbocation, making it a better candidate for cationic initiated polymerization.
On the other hand, in anionic polymerization, an anionic initiator generates an anion, which acts as a nucleophile, initiating the polymerization process. In this case, the electron-donating nature of the carboxylic acid group can stabilize the anion, making it a better candidate for anionic initiated polymerization.
Therefore, a carboxylic acid group substituted onto an alkene would be a better candidate for cationic initiated polymerization due to its electron-withdrawing nature, which can stabilize the carbocation intermediate formed during the polymerization process.