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Methanol

CH4O organic

Properties

StateLiquid (volatile)
ColorColorless
SolubilityMiscible with water in all proportions
Melting Point-97.6°C
Boiling Point64.7°C

About Methanol

Methanol is the simplest alcohol — one carbon, three hydrogens, one hydroxyl — and it is the chemical that gave 'wood alcohol' its name back when destructive distillation of hardwood logs was the only way to get it. Modern industrial methanol comes from synthesis gas: CO + 2H2 → CH3OH over a Cu/ZnO/Al2O3 catalyst at 50-100 atm and 220-280°C, with the syngas itself made by steam reforming of natural gas. Global methanol production runs around 110 million tonnes a year, and the demand stack has changed dramatically over the last two decades. The historic uses (formaldehyde for resins, MTBE for gasoline blending, acetic acid via the Cativa process) are still huge, but the fastest-growing segment is methanol-to-olefins (MTO) in China — turning coal-derived methanol into ethylene and propylene that used to come from naphtha cracking. Methanol is also having a moment as a marine bunker fuel: Maersk has been ordering dual-fuel methanol container ships, betting on green methanol from CO2 + electrolytic H2 to decarbonize shipping. In the lab, MeOH is the cheap polar protic solvent that runs reversed-phase HPLC, washes silica columns, and recrystallizes everything from caffeine to amino acids. The dark side of methanol is its metabolism: alcohol dehydrogenase oxidizes it to formaldehyde, then aldehyde dehydrogenase oxidizes that to formic acid. Formate inhibits cytochrome c oxidase, which kills retinal ganglion cells preferentially — which is why ingestion of as little as 10 mL produces blindness and 30 mL kills.

Where you'll encounter it

If you have ever pumped windshield washer fluid into your car in the dead of winter and noticed the bottle is mostly methanol, that's the freeze-point depressant doing its job — pure water freezes solid in your reservoir at 0°C; 50% MeOH/water stays liquid down to about -35°C. In a teaching organic lab, MeOH is the workhorse recrystallization solvent for caffeine extraction from tea: the crude residue dissolves in hot MeOH, hot-filters, and crystallizes back out cold as silky white needles. The grim case-report literature on methanol poisoning is essential reading for ER residents — the smell of methanol on a patient's breath after ingesting bootleg liquor (counterfeit vodka in some countries) is the signal to start IV fomepizole or an ethanol drip immediately, because ethanol outcompetes methanol for alcohol dehydrogenase and buys time for hemodialysis to clear the methanol before the formaldehyde and formate hit.

Common Uses

  • Feedstock for formaldehyde (Hoechst-Wacker-Celanese process) and acetic acid (Cativa)
  • Methanol-to-olefins (MTO) for ethylene and propylene production from coal-derived syngas
  • Marine bunker fuel for dual-fuel container ships (Maersk fleet)
  • Reversed-phase HPLC mobile phase and recrystallization/extraction solvent
  • Antifreeze and freeze-point depressant in windshield washer fluid

Safety Information

GHS: H225 (highly flammable liquid), H301+H311+H331 (toxic by oral, dermal, inhalation), H370 (causes damage to organs — optic nerve, CNS). Airborne exposure is limited on both an 8-hour average and a short-term basis, at levels a poorly ventilated bench can exceed. Flash point 11°C, autoignition 470°C. Burns with a nearly invisible blue flame in daylight — historic motorsport hazard at Indy, fire crews used water sprays to find the flame. Acute oral toxicity profound: ~10 mL causes blindness (formate damage to retinal ganglion cells via cytochrome c oxidase inhibition), 30 mL fatal. Antidotes: fomepizole (4-methylpyrazole, blocks ADH) or ethanol IV drip (competes for ADH), plus hemodialysis. Skin and inhalation absorption are also significant — gloves and ventilation are not optional. Never substitute for ethanol in any consumable application.

This safety summary is for educational reference only and may not be complete. It is not a substitute for Safety Data Sheets (SDS), medical advice, or professional chemical safety guidance. Always consult appropriate SDS and qualified professionals before handling chemicals. We deliberately do not publish occupational exposure limits or other regulatory thresholds: those values are revised over time and differ between jurisdictions, so the only correct source is the current SDS and the regulations that apply where you work.

Constituent Elements

Frequently Asked Questions

What is the molar mass of methanol?
CH3OH is 32.042 g/mol: C (12.011) + 4 H (4.032) + O (15.999). At density 0.792 g/mL, that means 1 mol occupies about 40.5 mL, and a 100 mL recrystallization solvent volume is ~2.47 mol of MeOH. Useful for solvent stoichiometry when MeOH is also acting as a reactant (transesterifications, methylations).
Why is methanol toxic when ethanol is just intoxicating?
Both alcohols are oxidized by alcohol dehydrogenase. Ethanol → acetaldehyde → acetate (the second step is fast, so acetaldehyde doesn't accumulate much). Methanol → formaldehyde → formate, and formate inhibits cytochrome c oxidase, choking off mitochondrial respiration. Retinal ganglion cells and optic nerve are especially vulnerable — that's the blindness — and severe metabolic acidosis follows. The treatment exploits this: give IV ethanol or fomepizole to occupy ADH and stop methanol metabolism, then dialyze the unmetabolized methanol out.
How is industrial methanol actually made?
From synthesis gas: CO + 2H2 → CH3OH over a Cu/ZnO/Al2O3 catalyst at 50-100 bar and 220-280°C. The syngas typically comes from steam methane reforming of natural gas (CH4 + H2O → CO + 3H2), so the carbon and hydrogen both originate from CH4. Conversion per pass is only 10-15% because the equilibrium is unfavorable, so unreacted gas recycles. Modern plants run 5000+ tonnes/day. The newer 'green methanol' route swaps the CO/H2 source for captured CO2 + electrolytic H2 from renewable power — same downstream catalyst, much lower carbon intensity, and Maersk's bet on shipping decarbonization.