Dimethyl sulfoxide (data page)

This page provides supplementary chemical data on dimethyl sulfoxide.

Material Safety Data Sheet

The handling of this chemical may incur notable safety precautions. It is highly recommend that you seek the Material Safety Datasheet (MSDS) for this chemical from a reliable source such as SIRI, and follow its directions.

Structure and properties

Structure and properties
Index of refraction,[1] nD	1.4795 at 20 °C 1.4787 at 21 °C
Abbe number	?
Dielectric constant,[2] εr	48 ε0 at 20 °C
Bond strength	?
Bond length	?
Bond angle	?
Magnetic susceptibility	?
Surface tension[2]	43 dyn/cm at 20 °C
Viscosity	2.14 mPa·s[2] at 20 °C 1.1 mPa·s[1] at 27 °C

Thermodynamic properties

Phase behavior
Triple point	291.67 K (18.52 °C), ? Pa
Critical point[2]	720 K (447 °C), 5630 kPa
Std enthalpy change of fusion, ΔfusHo	14.37 kJ/mol
Std entropy change of fusion, ΔfusSo	49.26 J/(mol·K)
Std enthalpy change of vaporization, ΔvapHo	52.9 kJ/mol
Std entropy change of vaporization, ΔvapSo	? J/(mol·K)
Solid properties
Std enthalpy change of formation, ΔfHosolid	? kJ/mol
Standard molar entropy, Sosolid	? J/(mol K)
Heat capacity, cp	149.40 J/(mol·K)
Liquid properties
Std enthalpy change of formation, ΔfHoliquid	−203.4 kJ/mol
Standard molar entropy, Soliquid	188.78 J/(mol·K)
Enthalpy of combustion, ΔcHo	−2037.3 kJ/mol
Heat capacity, cp	153 J/(mol·K) at 25 °C
Gas properties
Std enthalpy change of formation, ΔfHogas	−150.5 kJ/mol
Standard molar entropy, Sogas	? J/(mol·K)
Heat capacity, cp	? J/(mol·K)

Vapor pressure of liquid

vapor pressure at 20 °C = 0.556 mbar = 0.417 mmHg^[2]

log₁₀ of dimethyl sulfoxide vapor pressure. Uses formula ${\displaystyle \log _{e}P_{\text{mmHg}}={}}$${\displaystyle \log _{e}{\frac {760}{101.325}}-4.215616\log _{e}(T+273.15)-{\frac {7522.806}{T+273.15}}+46.78064-2.450859\times 10^{-7}(T+273.15)^{2}}$ obtained from CHERIC^[3]

Distillation data

Vapor-liquid equilibrium for dimethyl sulfoxide/water[4] P = 550 mm Hg BP Temp. °C  % by mole water liquid vapor 168.4 6.5 34.6 160.9 10.8 51.8 153.1 16.4 62.7 146.4 21.2 71.0 140.6 26.7 78.4 135.1 32.1 83.9 130.8 37.4 87.6 124.3 44.8 91.7 121.0 48.5 93.5 114.9 55.4 96.0 107.8 66.4 98.0 102.1 74.4 98.9 97.2 84.0 99.6 96.3 85.7 99.6 93.9 91.9 99.8

Vapor-liquid equilibrium for dimethyl sulfoxide/ethanol[4] P = 14.665 kPa BP Temp. °C  % by mole DMSO liquid vapor 55.80 48.75 1.0 64.50 59.75 1.6 66.75 64.00 2.5 70.80 71.00 3.6 76.50 76.25 5.0 81.50 80.50 6.0 91.50 85.00 13.0 100.74 90.00 21.0

Spectral data

UV-Vis
λmax	<220 nm
Extinction coefficient, ε	0.0034 %−1 cm−1 in unpHed water at 260 nm
IR
Spectrum	NIST
Major absorption bands	3000, 2900, 1200–1240, 1000–1080, 960, 690 cm−1
NMR
Proton NMR	2.54((CD3)2SO), 2.71 in D2O;[5]
Carbon-13 NMR	40ppm;
Other NMR data
MS
Masses of main fragments