Chlorogenic acid occurs in green coffee beans and is used in weight-loss treatments. Which product is obtained in good yield when chlorogenic acid is reacted with an excess of sodium carbonate solution at room temperature? ($R = \text{C}_5\text{H}_9\text{O}_2$ and does not take part in the reaction with sodium carbonate.)
Chemistry 9701 · AS & A Level · Carboxylic acids and derivatives