isopentyl alcohol is reacted with acetic acid to make isopentyl acetate through Fischer esterification. Sulfuric acid is used to assist the reaction.
After the reaction, the solution is washed with sodium bicarbonate.
What reactions take place during this washing? What gas is produced? How does this separate unreacted acetic acid and sulfuric acid into a separate aqueous layer?
NaHCO3 reacts with the excess acetic acid to form CO2 gas (+H2O and sodium acetate). All of the acetic acid and H2SO4 are neutralized with the NaHCO3, forming Na2SO4 and NaC2H3O2, both of which are soluble in the water layer. Isopentyl acetate is only slightly soluble in water.
Perfect. Thanks!
so what are the observations? just colourless bubbles?
During the washing with sodium bicarbonate, several reactions take place:
1. Acid-base reaction: Sulfuric acid (H2SO4) reacts with sodium bicarbonate (NaHCO3) to form carbonic acid (H2CO3), which then decomposes into water (H2O) and carbon dioxide (CO2) gas. The general equation is:
H2SO4 + 2NaHCO3 → Na2SO4 + 2H2O + 2CO2
2. Acid-carboxylate reaction: Acetic acid (CH3COOH) reacts with sodium bicarbonate to form sodium acetate (CH3COONa), carbonic acid, water, and carbon dioxide gas. The general equation is:
CH3COOH + NaHCO3 → CH3COONa + H2O + CO2
The carbon dioxide gas produced is what helps to separate the unreacted acetic acid and sulfuric acid into a separate aqueous layer. Carbon dioxide is a gas, so as it bubbles out of the solution, it helps to carry along any dissolved acetic acid and release it into the gas phase. This reduces the concentration of acetic acid in the solution, effectively separating it from the aqueous layer.
Once the separation occurs, the remaining sodium acetate and sulfuric acid, which are both water-soluble, remain in the aqueous layer. They can then be further separated by techniques such as extraction or distillation.