Methanol Boiling Point, Density & Thermophysical Properties (CH3OH)

Overview

Engineering reference data for Methanol Methyl Alcohol Properties CH3OH in chemistry.

Key Formulas

Ideal Gas Law

$PV = nRT$

Pressure × Volume = moles × gas constant × temperature.

Molarity

$M = \frac{n}{V}$

Moles of solute per liter of solution.

pH

$pH = -\log_{10}[H^+]$

Measure of acidity.

Variables

Symbol	Description	Unit
$P$	Pressure	Pa
$V$	Volume	m³
$n$	Moles	mol
$R$	Gas constant	8.314 J/(mol·K)

Thermophysical Properties

The following table summarizes key thermophysical properties of methanol at 25°C (298 K) and 1 bar, unless otherwise noted.

Phase Behavior

Methanol exists as a liquid under standard conditions (25°C, 1 atm). Its phase diagram shows the following critical points:

• Triple Point: 175.50 K (−97.7°C) at 1.86 × 10⁻⁷ MPa
• Critical Point: 513.4 K (240.2°C) at 8.22 MPa

The curve between the critical point and triple point represents the boiling point variation with pressure and the saturation pressure as a function of temperature. At the critical point, there is no distinct phase change when pressure increases or heat is added—the liquid and gas phases become indistinguishable.

Safety Properties

Property	Value	Condition
Flammable	Yes	Both gas and liquid phases
Flash Point	11°C (52°F)	—
Autoignition Temperature	464°C (867°F)	—
Toxicity	Highly toxic	May cause blindness
Vapor Density	1.11	Relative to air (vapors heavier than air)

Caution: Methanol vapors may explode if ignited. Methanol is toxic by ingestion, inhalation, and dermal absorption.

References

• Original Source