Ethanol can be produced by two different methods: fermentation of glucose, and the hydration of ethene. Compare these two methods of producing ethanol, including the raw materials used and the conditions required for each method.

Fermentation of glucose:
1. Raw material: glucose (sugar) derived from plants.
2. Catalyst: yeast (enzymes).
3. Conditions: low to moderate temperature (≈25–37 °C), anaerobic (no oxygen).
4. Product: dilute ethanol in aqueous solution – requires distillation to obtain pure ethanol.

Hydration of ethene:
1. Raw material: ethene, obtained from crude oil (non‑renewable).
2. Catalyst: acid (e.g. H₂SO₄) or phosphoric acid with a catalyst, often in a continuous process.
3. Conditions: high temperature and high pressure.
4. Product: relatively pure ethanol produced directly, no need for distillation.

Comparison:
- Fermentation uses renewable plant sugars; hydration uses non‑renewable ethene.
- Fermentation relies on biological enzymes; hydration uses chemical catalysts.
- Fermentation operates at mild temperatures and no oxygen; hydration requires high temperature and pressure.
- Fermentation yields a dilute solution needing distillation; hydration gives a more concentrated, purer ethanol directly.