1,2-Ethanedithiol

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1,2-Ethanedithiol
1,2-Ethanedithiol
Ball-and-stick model of ethane-1,2-dithiol
Space-filling model of ethane-1,2-dithiol
IUPAC name Ethane-1,2-dithiol
Other names Dimercaptoethane
1,2-Ethanedithiol
Identifiers
CAS number [540-63-6]
RTECS number KI3325000
SMILES SCCS
Properties
Molecular formula C2H6S2
Molar mass 94.20 g/mol
Appearance Colorless liquid
Density 1.123 g/cm³, liquid
Melting point

-41 °C

Boiling point

146 °C
63 °C @46 mmHg

Solubility in water Slightly sol
Solubility in other solvents Good solubility in
most organic solvents
Acidity (pKa) ~11
Refractive index (nD) 1.5589 (D-line, 25 °C)
Hazards
EU classification Toxic (T)
NFPA 704
2
2
0
 
R-phrases R10 R22
S-phrases S16
Flash point 50 °C
Related compounds
Related thiols Ethanethiol; 1,3-Propanedithiol; 1,2-Benzenedithiol; Thiophenol
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

Infobox disclaimer and references

1,2-Ethanedithiol is an odorous, colorless liquid with the formula C2H4(SH)2. It is a common building block in organic synthesis and an excellent ligand for metal ions.

[edit] Preparation

1,2-Ethanedithiol is commercially available. It can be prepared by the action of 1,2-dibromoethane on thiourea followed by hydrolysis.[1]

[edit] Applications

This compound is widely used in organic chemistry because it reacts with aldehydes and ketones to give 1,3-dithiolanes, which are useful intermediates. [2]

C2H4(SH)2 + RR'CO → C2H4S2CRR' + H2O
Protecting a carbonyl group by converting it to a 1,3-dithiolane, using 1,2-ethanedithiol

Other 1,2- and 1,3-dithiols undergo this reaction to give related 1,3-dithiolanes and 1,3-dithianes (six-membered rings). Diols such as ethylene glycol undergo analogous reactions to 1,3-dioxalanes and 1,3-dioxanes. One distinguishing feature of the dithiolanes and dithianes derived from aldehydes is that the methyne group can be deprotonated and the resulting carbanion alkylated.

[edit] References

  1. ^ Speziale, A. J. (1963). "Ethanedithiol". Org. Synth.; Coll. Vol. 4: 401. 
  2. ^ R. E. Conrow "Ethanedithiol" in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. DOI: 10.1002/047084289.
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