Question

Why is methanol sometimes called wood alcohol? Describe the modern synthesis of methanol. What are some uses of methanol?

Short answer

Methanol is sometimes called "wood alcohol" because it was originally produced by the destructive distillation of wood. In modern methanol synthesis, natural gas (mainly methane) is transformed into synthesis gas, purified, mixed with a copper-zinc-aluminum catalyst, and subject to high temperature and pressure to generate methanol. Methanol has various uses, including as a fuel, a raw material for chemical production, antifreeze, solvent, and as a denaturant in alcohol.

Step-by-step solution

Understanding the term "Wood Alcohol"

Methanol is sometimes called "wood alcohol" because it was first produced by the destructive distillation of wood. This process involves heating wood until it breaks down into various chemicals, including methanol. Although methanol can be obtained from various sources today, the historical association with wood remains in its common name as "wood alcohol".

Modern Synthesis of Methanol

The modern synthesis of methanol involves a process called the "Methanol Synthesis Loop". This process consists of the following steps: 1. Natural gas (mainly methane) is first transformed into synthesis gas (a mixture of hydrogen and carbon monoxide) through steam reforming or partial oxidation. 2. The synthesis gas then goes through a purification process, where impurities like sulfur or other unwanted components are removed. 3. The purified synthesis gas is then mixed with a catalyst, typically a mixture of copper, zinc oxide, and aluminum oxide. 4. This mixture is subjected to high temperature (250–300°C) and pressure (50–100 atm), which results in a chemical reaction that generates methanol. 5. The methanol is then separated from any unreacted hydrogen, carbon monoxide, and other byproducts through distillation.

Uses of Methanol

Methanol has a variety of uses across different industries, some of which include: 1. Fuel: Methanol can be used as a fuel for internal combustion engines, racing cars, and even in fuel cells for generating electricity. 2. Chemical production: Methanol is a key raw material for producing formaldehyde, which is used in the production of resins, plastics, and plywood. 3. Antifreeze: Methanol is often used as an antifreeze in pipelines and windshield washer fluid due to its low freezing point and ability to lower the freezing point of water. 4. Solvent: Methanol is a polar solvent and is used in various chemical processes for the synthesis of pharmaceuticals, coatings, and adhesives. 5. Denaturing alcohol: Methanol is added to ethanol to make it unfit for human consumption, turning it into a denatured alcohol used in various cleaning products and industrial applications.