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IUPAC name 1,3-Propanedithiol
Other names 1,3-dimercaptopropane
CAS number 109-80-8
RTECS number TZ2585500
Molecular formula C3H8S
Molar mass 108.23 g/mol
Appearance colourless liquid, stench
Density 1.078 g/cm³
Melting point

-79 °C

Boiling point

169 °C

Solubility in water slight
Solubility in solvents all organic solvents
Refractive index (nD) 1.539
Dipole moment 0 D
Main hazards stench
R-phrases 36/37/38
S-phrases 26
Flash point 138 °F
Related Compounds
Related compounds 1,2-ethanedithiol
lipoic acid
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

Infobox disclaimer and references

1,3-Propanedithiol is the chemical compound with the formula HSCH2CH2CH2SH. This dithiol is a useful reagent in organic synthesis. This liquid, which is readily available commercially, has an intense stench.

Use in organic synthesis

1,3-Propanedithiol is mainly used for the protection of aldehydes and ketones via their reversible formation of dithianes.[1] A prototypical reaction is its formation of 1,3-dithiane from from formaldehyde.[2] The reactivity of this dithiane illustrates the concept of umpolung.

The unpleasant odour of 1,3-propanedithiol has encouraged the development of alternative reagents that generate similar derivatives.[3]

Use in inorganic synthesis

1,3-Propanedithiol reacts with metal ions to form chelate rings. Illustrative is the synthesis of the diiron derivative:[4]

Fe3(CO)12 + C3H6(SH)2 → Fe2(S2C3H6)(CO)6 + H2 + Fe(CO)5 + CO


The stench of 1,3-propanedithiol can be neutralized with bleach.

See also


  1. Conrow, R. E.; Le Huérou, Y. (2004). 1,3-Propanedithiol. J. Wiley & Sons, New York. doi:10.1002/047084289.  Text " Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) " ignored (help)
  2. Corey, E. J.; Seebach, D. (1988). "1,3-Dithiane". Org. Synth.; Coll. Vol. 6: 556. 
  3. Liu, Q.; Che, G. Yu, H.; Liu, Y.; Zhang, J. Zhang, Q.; Dong, D. (2003). "The First Nonthiolic, Odorless 1,3-Propanedithiol Equivalent and Its Application in Thioacetalization". Journal of Organic Chemistry. 68: 9148 – 9150. doi:10.1021/jo034702t. 
  4. Winter, A.; Zsolnai, L. and Huttner, G. (1982). "Zweikernige und dreikernige Carbonyleisenkomplexe mit 1,2- und 1,3-Dithiolatobrückenliganden". Zeitschrift für Naturforschung. 37b: 1430–1436.