Methanol Methyl Alcohol Properties CH3OH
Reference data and engineering information about methanol methyl alcohol properties ch3oh for chemistry applications.
Overview
Engineering reference data for Methanol Methyl Alcohol Properties CH3OH in chemistry.
Key Formulas
Ideal Gas Law
Pressure × Volume = moles × gas constant × temperature.
Molarity
Moles of solute per liter of solution.
pH
Measure of acidity.
Variables
| Symbol | Description | Unit |
|---|---|---|
| Pressure | Pa | |
| Volume | m³ | |
| Moles | mol | |
| 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.
Property | Value | Unit |
|---|---|---|
| Molecular Weight | 32.042 | g/mol |
| Boiling Point | 64.7 | °C |
| Melting Point | -97.6 | °C |
| Flash Point | 11 | °C |
| Autoignition Temperature | 464 | °C |
| Critical Temperature | 240.2 | °C |
| Critical Pressure | 8.22 | MPa |
| Critical Density | 281 | kg/m³ |
| Critical Volume | 114 | cm³/mol |
| Density (liquid) | 786.3 | kg/m³ |
| Density (gas, 0.17 bar) | 0.22 | kg/m³ |
| Specific Gravity (liquid) | 0.79 | relative to water |
| Specific Gravity (gas) | 1.11 | relative to air |
| Cp (liquid) | 2.53 | kJ/kg·K |
| Cp (gas, 0.17 bar) | 3.62 | kJ/kg·K |
| Cv (liquid) | 2.12 | kJ/kg·K |
| Cv (gas, 0.17 bar) | 2.95 | kJ/kg·K |
| Specific Heat Ratio (gas), γ | 1.23 | Cp/Cv |
| Heat of Evaporation | 1165 | kJ/kg |
| Heat of Fusion | 99 | kJ/kg |
| Heat of Combustion (liquid) | -22689 | kJ/kg |
| Heat of Formation (liquid) | -7459 | kJ/kg |
| Thermal Conductivity | 0.202 | W/m·K |
| Dynamic Viscosity | 0.544 | cP |
| Kinematic Viscosity | 0.692 | cSt |
| Surface Tension | 0.02207 | N/m |
| Sound Velocity (liquid) | 1100 | m/s |
| Sound Velocity (gas, 0.17 bar) | 297 | m/s |
| Vapor Pressure (25°C) | 16.9 | kPa |
| Solubility in Water | 1000 | mg/mL (miscible) |
| Acidity (pKa1) | 15.3 | - |
| log Kow | -0.77 | - |
Source: engineeringtoolbox.com
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.