What Is Anhydrous Methanol?

Anhydrous means
••• desert image by AlexQ from Fotolia.com

Anhydrous methanol is methanol that is free of water. Methanol is hygroscopic, which means it absorbs moisture, including moisture from the air.

Synthetic Reactions

Pharmaceuticals and many other useful materials are made by reacting precursors in a process called chemical synthesis. Many reactions are conducted in liquids other than water. The presence of a small amount of water can produce undesirable results.

Anhydrous Solvents

Chemists need to determine the identity of unknown substances. Contaminants in the solvents can interfere with these tests.

Storing Anhydrous Solvents

The air space in the bottle of an anhydrous solvent is usually filled with dry nitrogen or argon instead of air. Dry nitrogen or argon contain insignificant amounts of water vapor. When an anhydrous solvent is opened, the airspace above the solvent should be replaced with fresh dry gases.

Store Over Hygroscopic Solids

In the lab, hygroscopic solids such as anhydrous magnesium sulfate are sometimes added to bottles of solvent to remove any absorbed water.

Other Solvent Problems

Some solvents form a mixture with water that cannot be purified by single batch distillation. This is called an azeotrope. Complex distillation methods are used to make these solvents anhydrous. Methanol does not form an azeotrope with water, but solvents that do should be handled as described above.

Related Articles

Definition of Vapor Distilled Water
How to Make Bromine Water in the Chemistry Lab
Alternative Solvents to Benzene
What is Ethanolic Potassium Hydroxide?
Which Burns Hotter: Ethanol or Methanol?
Chemicals That Absorb Moisture
How to Make MSM Crystals
How to Separate Alcohol From Water
What is the Meaning of Homogeneous?
Definition of Vapor Distilled Water
How to Dissolve Sulphur
How to Calculate Solubilities
Urethane vs. Polyurethane
What Does Solute Mean?
How Is Isopropyl Alcohol Made?
How to Make a Vacuum Chamber for a Science Experiment
Is Methanol & Isopropyl Alcohol the Same Thing?
Chemicals in Dry-Erase Markers
What Happens When You Mix Pool Chlorine & Break Fluid?