Sodium ethyl xanthate

Sodium ethyl xanthate

Names
IUPAC name sodium O-ethylcarbonodithioate
Other names Sodium ethylxanthogenate Sodium-O-ethyl dithiocarbonate
Identifiers
CAS Number	140-90-9 Y=
3D model (JSmol)	Interactive image
ChemSpider	8493 N
ECHA InfoCard	100.004.947
EC Number	205-440-9
PubChem CID	8824
InChI InChI=1S/C3H6OS2.Na/c1-2-4-3(5)6;/h2H2,1H3,(H,5,6);/q;+1/p-1 Key: RZFBEFUNINJXRQ-UHFFFAOYSA-M
SMILES CCOC(=S)[S-].[Na+]
Properties
Chemical formula	C3H5NaOS2
Molar mass	144.18 g·mol−1
Appearance	Pale yellow powder
Density	1.263 g/cm3
Melting point	182 to 256 °C (360 to 493 °F; 455 to 529 K)
Boiling point	decomposes
Solubility in water	450 g/L (10 °C)
Acidity (pKa)	1.6
Basicity (pKb)	12.4
Hazards
R-phrases (outdated)	R15 R21 R22 R29 R36 R38
S-phrases (outdated)	S3 S9 S35 S36 S37 S38 S39 S16 S23 S51
Autoignition temperature	250 °C (482 °F; 523 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YN ?)
Infobox references

Sodium ethyl xanthate (SEX) is an organosulfur compound with the chemical formula CH₃CH₂OCS₂Na. It is a pale yellow powder, which characteristically hydrolyzes to release malodorous products. Sodium ethyl xanthate is predominantly used in the mining industry as a flotation agent.

Xanthates are prepared by the action of metal alkoxides on carbon disulfide:

Sodium ethyl xanthate is a pale yellow powder. It is relatively stable at high pH and rapidly hydrolyses at pH <9 at 25 °C. It is the conjugate base of the unknown strong acid with pK_a of 1.6 and pK_b estimated as 12.4 for the conjugate base. Sodium ethyl xanthate easily adsorbs on the surface of solid sulfides.

Sodium ethyl xanthate decomposes in water increases with decreasing pH and with increasing temperature. Three pathways are proposed:

A. Dissociation into xanthic acid and then to carbon disulfide and alcohol.

B. Oxidation to dixanthogen.

C. Hydrolytic decomposition

Reactions A and B are minor and require acidic conditions. Reaction C proceeds in neutral or alkaline pH and is self-accelerating, as it is catalysed by the alcohol formed as a product. Its rate increases with concentration of the reagents and with temperature, from 1.1%/day at 20 °C to 4.6%/day at 40 °C for a 10% solution at pH=10. A decrease in pH from 10 to 6.5 increases the decomposition rate from 1.1%/day to 16%/day. Decomposition is also accelerated by the presence of metals, such as copper, iron, lead or zinc, which act as a catalyst.

Sodium ethyl xanthate can be identified through optical absorption peaks in the infrared (1179, 1160, 1115, 1085 cm⁻¹) and ultraviolet (300 nm) ranges. There are at least six chemical detection methods:

Sodium ethyl xanthate can also be quantified using gravimetry, by weighing the lead xanthate residue obtained after reacting SEX with 10% solution of lead nitrate. There are also several electrochemical detection methods, which can be combined with some of the above chemical techniques.

Sodium ethyl xanthate is predominantly used in the mining industry as flotation agent for recovery of metals, such as copper, nickel, silver or gold, as well as solid metal sulfides or oxides from ore slurries. This application was introduced by Cornelius H. Keller in 1925. Other applications include defoliant, herbicide and an additive to rubber to protect it against oxygen and ozone.