Some Commercially Important Alcohols
NCERT Reference: Chapter 7 – Alcohols, Phenols and Ethers – Pages 184–185
Quick Notes
- Methanol (CH3OH) is a poisonous alcohol obtained from syngas or CO + H2 mixture.
- Ethanol (C2H5OH) is commonly known as alcohol; used in beverages, solvents, and medical preparations.
- Both alcohols are miscible in water and flammable.
- Methanol is toxic even in small quantities
- Ethanol in excess is intoxicating but less toxic than methanol.
Full Notes
Methanol and ethanol are among the most widely used alcohols in laboratories and industries. They serve as solvents, fuels, and intermediates in various chemical processes.
Methanol (CH3OH)

Preparation
Industrially prepared by catalytic hydrogenation of carbon monoxide:

Catalyst: ZnO/Cr2O3 at high pressure and temperature
Properties
- Colourless liquid, boiling point ≈ 337 K
- Miscible with water in all proportions
- Highly toxic: ingestion can cause blindness, coma, or death due to oxidation to formaldehyde and formic acid
Uses
- As a solvent in paints, varnishes, and adhesives
- In manufacture of formaldehyde, methylamines, and plastics
- As an industrial fuel and antifreeze
- Denaturant for ethanol (to prevent human consumption)
Ethanol (C2H5OH)

Preparation
Obtained by fermentation of sugars (glucose and fructose) obtained from the breaking down of sucrose in presence of zymase enzymes (from yeast)

Can also be prepared by hydration of ethene using H2SO4 catalyst (see section 7.4).
Properties
- Colourless, volatile liquid with boiling point ≈ 351 K
- Pleasant smell; miscible with water
- Causes intoxication when consumed; excessive use damages liver and nervous system
Uses
- As an alcoholic beverage (in diluted form)
- In medicinal preparations (tinctures, cough syrups)
- As solvent in perfumes, drugs, varnishes
- In manufacture of ethyl esters, acetic acid, etc.
- As biofuel and industrial solvent
Toxicity & Denaturation
- Denatured by adding methanol, pyridine, or CuSO4 to prevent misuse
- This ethanol is called denatured spirit
Summary
- Methanol is produced from CO and H2 and is highly toxic.
- Ethanol is produced by fermentation and hydration of ethene and is widely used as a solvent and fuel.
- Both alcohols are miscible with water and flammable.
- Denatured spirit is ethanol rendered unfit for drinking by additives.