In the reaction: Protection of 1-Phenylethanol by 3,4-Dihydro-2H-pyran, 1-phenylethanol, 3,4-Dihydro-2H-pyran and anhydrous ether were added first and stirred in ice-water bath before acid catalyst p-toluenesulfonic acid monohydrate was added. The reaction was kept at 0 deg cel for another 5 mins before allowing it to react at room temperature.
1. Why was the reaction stirred in ice-water bath before acid catalyst p-toluenesulfonic acid monohydrate was added?
2. Why was the reaction kept at 0 deg cel for another 5 mins?
3. Why was the temperature raised to room temperature subsequently?