1,2-Ethanedithiol

1,2-Ethanedithiol
IUPAC name Ethane-1,2-dithiol
Other names Dimercaptoethane 1,2-Ethanedithiol
Identifiers
CAS number	540-63-6 Y
ChemSpider	13865015 Y
UNII	92T634FLAR Y
RTECS number	KI3325000
Jmol-3D images	Image 1
SMILES SCCS
InChI InChI=1S/C2H6S2/c3-1-2-4/h3-4H,1-2H2 Y Key: VYMPLPIFKRHAAC-UHFFFAOYSA-N Y InChI=1/C2H6S2/c3-1-2-4/h3-4H,1-2H2 Key: VYMPLPIFKRHAAC-UHFFFAOYAA
Properties
Molecular formula	C2H6S2
Molar mass	94.20 g mol−1
Appearance	Colorless liquid
Density	1.123 g/cm³
Melting point	−41 °C; −42 °F; 232 K
Boiling point	146 °C; 295 °F; 419 K (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)
R-phrases	R10 R22
S-phrases	S16
NFPA 704	2 2 0
Flash point	50 °C; 122 °F; 323 K
Related compounds
Related thiols	Ethanethiol; 1,3-Propanedithiol; 1,2-Benzenedithiol; Thiophenol
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

1,2-Ethanedithiol is a colorless liquid with the formula C₂H₄(SH)₂. It has a very characteristic odor which is compared by many people to rotten cabbage. It is a common building block in organic synthesis and an excellent ligand for metal ions.

Preparation

1,2-Ethanedithiol is prepared commercially by the reaction of 1,2-dichloroethane with aqueous sodium bisulfide. In the laboratory, it can also be prepared by the action of 1,2-dibromoethane on thiourea followed by hydrolysis.^[1]

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

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.

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