Methanol is the simplest form of alcohol, which is colorless, volatile, and highly flammable. Methanol is also referred to as Methyl Alcohol or Wood Alcohol. It is an excellent fuel and has the potential to run automobiles, fuel cells, and gas stoves. It plays an essential role in various reactions, ranging from esterification to acting as a hydrogen source.

In this article, we will study methanol, its structure, properties, production methods, along with its environmental impact in detail.

What is Methanol

Methanol is the simplest form of aliphatic alcohol, with the formula CH₃OH. It is a light, volatile, colorless, and flammable liquid with a distinctive alcoholic odor similar to ethanol. It is also known as wood alcohol.

It is used in various applications, including as a precursor to other chemicals, in producing formaldehyde and acetic acid, and as a clean energy resource for fueling cars, trucks, buses, ships, fuel cells, boilers, and cook stoves. However, it is important to note that drinking or inhaling methanol can lead to severe health effects, including coma, convulsions, blindness, nervous system damage, and even death.

Learn, Organic Compounds

Occurrence of Methanol

It has been observed that healthy human persons contain minimal levels of methanol. Studies have indicated that test subjects’ exhaled breath had a mean of 4.5 ppm. In humans, pectin, which is present in fruit, is metabolized to produce 0.45 g/d of endogenous methanol. Up to 1.4 g of methanol can be produced from one kilogram of apples.

Anaerobic bacteria and phytoplankton create methanol. There is an abundance of methanol in star-forming regions of space. It serves as a marker for these areas in astronomy as well. Its emission lines provide spectral information about methanol.

Methanol Formula

Chemical formula for methanol is CH₃OH

Methanol Formula indicates that it contains one carbon, one oxygen, and four hydrogen atoms. Methanol, also known as methyl alcohol, is the simplest alcohol, consisting of a methyl group linked with a hydroxyl group.

Structure of Methanol

Methanol is a tetrahedral molecule with the carbon atom at the center and the hydrogen, oxygen, and methyl groups attached to it. Each of them is bonded to the carbon atom with a single bond.

Methanol Structure

Properties of Methanol

Properties of Methanol are classified into following types

• Physical Properties
• Chemical Properties

Physical Properties of Methanol

Some of the key physical properties of methanol includes:

Methanol Chemical Properties

Methanol with the chemical formula CH₃OH exhibits several chemical properties, which is:

• Acidity and Basicity: Methanol is a weak acid and a weak base. It can donate protons (H⁺) to stronger bases and accept protons (H⁺) from stronger acids.

• Reactivity: Methanol is a reactive chemical that can undergo a variety of reactions. It can be oxidized to form formaldehyde, reduced to form methane, and reacted with halogens to form alkyl halides.

• Flammability: Methanol is a liquid with a flash point of 11.7 °C. This means that it will easily ignite and can produce explosive vapors.

• Toxicity: Methanol is a highly toxic substance that can cause blindness, kidney damage, and death. It is essential to handle Methanol carefully and avoid exposure to it.

• Combustion of Methanol: When methanol burns in the air, it forms carbon dioxide and water. It is highly flammable and burns with a pale-blue, non-luminous flame. The chemical equation for the combustion of methanol is:

2CH₃OH + 3O₂ → 2CO₂ + 4H₂O

pH of Methanol

The pH of methanol is 8.3. Methanol-water mixtures have autoprotolysis constants between 14 (water) and 16.6 (methanol), so neutral in these mixtures ranges from pH 7 to pH 8.3

Methanol Boiling Point

Boiling point of methanol is 64.7 °C

Methanol Density

Density of methanol at room temperature is 791.80 kg/m³

Methanol Molecular Weight

Molecular Weight of methanol is 32.04 g/mol³

Production of Methanol

Some methods of producing methanol includes:

Steam-Reforming Natural Gas: This is the most common method for producing methanol. It involves partial oxidation of methane under controlled conditions in a homogeneous or catalytic reaction process. The synthesis gas produced is then fed into a reactor with catalysts, such as CuO/ZnO/Al₂O₃, to produce methanol and water vapor.

Hydrogenation of CO and CO₂: In this method, methanol is produced from petroleum products (synthesis gas) via hydrogenation of CO and CO₂ and reversed water-gas shift reaction.

Biomass Gasification: The production of methanol from biomasses for large-scale production is done primarily via gasification, which involves partial oxidation by steam and air to produce synthetic gas.

Green Hydrogen and Recycled Carbon Dioxide: Methanol can also be produced from renewable sources, such as green hydrogen and recycled carbon dioxide.

Reactions using Methanol

Methanol can be used in various chemical reactions because of its alcohol functional group. Some of the reactions involving methanol include:

Esterification: Methanol can react with carboxylic acids in the presence of an acid catalyst to form methyl esters and water. This reaction is commonly used in the production of biodiesel, where methanol reacts with fatty acids to form methyl esters.

RCOOH + CH₃OH → RCOOCH₃ + H₂O

Methanolysis: In this reaction, methanol breaks down the compound into constituent parts. For example, triglycerides in vegetable oil can react with methanol to produce fatty acid methyl esters (biodiesel) and glycerol.

Triglycerides+ 3CH₃OH → 3CH₃COOR + Glycerol

Methanol as a Hydrogen source: Methanol can be used as a hydrogen source in reduction reactions. Catalytic reduction reactions using methanol as a transfer hydrogenating agent have gained significant attention.

R-NO₂ + 3CH₃OH+ Pt/C → R-NH₂ + 3CH₂O

Acetal Formation: Methanol reacts with aldehydes or ketones to form acetals or ketals, respectively. This reaction is often used to protect carbonyl groups in organic synthesis.

CH₃CHO + 2 CH₃OH → CH₃CH(OMe)₂ + H₂O

Uses of Methanol

The uses of Methanol are listed below:

• Formalin: Methanol is used to make formaldehyde, which is a typical commercial product used in kitchen counters, furniture, and interior moldings in vehicles. It is also used as a preservative in medicine and personal care items.

• Acetic acid: Methanol is a component of acetic acid, which is used for pickling in the food industry, household cleaners, and as an antiseptic in medical procedures.

• Synthetic resins: Methanol is used as a base material in producing synthetic resins.

• Solvents: Methanol is used as a solvent in various industries, including pharmaceuticals.

• Fuel: Methanol is used as a fuel for factories and electricity generation. It is also used to fuel cars, trucks, buses, etc.

• Adhesives, paint, and plywood: Methanol is used to produce adhesives, paint, and plywood used in construction.

• Pharmaceuticals: Methanol is used as a chemical agent in pharmaceuticals and agrochemicals.

Methanol vs Ethanol

Methanol is the simplest form of alcohol while ethanol is the second member of the alcohol family. They are part of same homologous series and differ by -CH₂ group and 14 units of mass. Methanol Methanol and Ethanol differs from each others in the following ways:

Learn, Functional Groups

Environmental Impact of Methanol

Methanol has both positive and negative environmental impacts. Here are some of the leading environmental impacts of methanol:

• Global Warming Potential: Methanol production has a low global warming potential, especially when produced from wood biomass.

• Air Pollution: Methanol is released into the environment during industrial uses and naturally from volcanic gases, vegetation, and microbes. Exposure to methanol can cause irritation of the eyes, nose, mouth, and throat. It can lead to liver damage, headaches, cardiac depression, nausea, vomiting, blurred vision, optic nerve damage, dizziness, and a feeling of intoxication.

• Hydrocarbon Airborne Emissions: Methanol fuel significantly reduces the reactivity of hydrocarbon emissions from automobiles, which can help reduce air pollution.

Also, Check

• Some Commercially Important Alcohols
• Formaldehyde Formula
• Azeotropic Mixture
• Formic Acid(HCOOH)

Methanol – Frequently Asked Questions

What is Molecular Formula of Methanol?

Molecular Formula of Methanol is CH₃OH.

What is Melting Point of Methanol?

The melting point of Methanol is -97.6 °C.

What is Methanol Poisoning?

Methanol Poisoning: It’s a serious health risk causing blindness, kidney damage, and even death if ingested; handle it with extreme caution.

What is Methanol Used for?

Methanol is used as a fuel, solvent, and key in producing formaldehyde, acetic acid, and synthetic resins.

What is Methanol’s Flash Point?

Flash Point of Methanol is 11.7 °C which means it is highly flammable, ignites easily, and produces explosive vapors.

What is Boiling Point of Methanol?

Methanol has Boiling Point of 64.7℃