Potassium amylxanthate
[CAS 2720-73-2]

Identification

• Classification: Organic raw materials >> Organic sulfur compound
• Name: Potassium amylxanthate
• Synonyms: Amylxanthic acid potassium salt
• Molecular Formula: C₆H₁₁OS₂.K
• Molecular Weight: 202.38
• CAS Registry Number: 2720-73-2
• EC Number: 220-329-5
• SMILES: CCCCCOC(=S)[S-].[K+]

Safety Data

• Hazard Symbols: GHS02;GHS05;GHS07;GHS08;GHS09 DangerGHS02
• Risk Statements: H228-H302-H312-H314-H315-H317-H318-H319-H361d-H373-H411-H412
• Safety Statements: P203-P210-P240-P241-P260-P261-P264-P264+P265-P270-P272-P273-P280-P301+P317-P301+P330+P331-P302+P352-P302+P361+P354-P304+P340-P305+P351+P338-P305+P354+P338-P316-P317-P318-P319-P321-P330-P332+P317-P333+P317-P337+P317-P362+P364-P363-P370+P378-P391-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Acute toxicity	Acute Tox.	4	H302
Skin irritation	Skin Irrit.	2	H315
Serious eye damage	Eye Dam.	1	H318
Skin sensitization	Skin Sens.	1	H317
Flammable solids	Flam. Sol.	2	H228
Skin corrosion	Skin Corr.	1	H314
Specific target organ toxicity - repeated exposure	STOT RE	2	H373
Reproductive toxicity	Repr.	2	H361d
Chronic hazardous to the aquatic environment	Aquatic Chronic	3	H412
Chronic hazardous to the aquatic environment	Aquatic Chronic	2	H411
Eye irritation	Eye Irrit.	2	H319
Acute toxicity	Acute Tox.	4	H312
Specific target organ toxicity - single exposure	STOT SE	3	H335
Flammable solids	Flam. Sol.	1	H228
Pyrophoric solids	Pyr. Sol.	1	H250
Skin corrosion	Skin Corr.	1B	H314
Acute toxicity	Acute Tox.	4	H332

chemBlink Chemical Story

Potassium amylxanthate, CAS 2720-73-2, commonly abbreviated PAX, is an alkyl xanthate flotation collector. Its structure contains a potassium counterion and an amyl xanthate anion, whose sulfur-rich functional group gives xanthates strong affinity for selected mineral surfaces.

Xanthates became some of the most important collectors in froth flotation of sulfide minerals. A collector modifies mineral surfaces so selected particles become sufficiently hydrophobic to attach to air bubbles. Potassium amylxanthate is a relatively strong collector used in beneficiation of copper, nickel, zinc and other sulfide-bearing ores, with actual selectivity depending on mineralogy and the rest of the reagent scheme.

The amyl chain contributes hydrophobic character, while the xanthate group provides the chemically active surface-binding region. On sulfide mineral surfaces, adsorption can involve metal-xanthate species, oxidation products such as dixanthogen, or combinations that depend on electrochemical conditions. This is why flotation chemistry cannot be reduced to a simple picture of one molecule sticking unchanged to one mineral.

PAX is commonly compared with ethyl, isopropyl and butyl xanthates. Changing the alkyl group changes collecting strength, solubility and selectivity. The amyl derivative is a more hydrophobic member of the family, useful when stronger collection is desired but requiring process control to avoid sacrificing selectivity.

References:
1. Wills BA, Finch JA. Wills' Mineral Processing Technology. 8th ed. Elsevier, 2016.
2. Fuerstenau MC, Jameson GJ, Yoon RH, eds. Froth Flotation: A Century of Innovation. SME, 2007.
3. Bulatovic SM. Handbook of Flotation Reagents. Elsevier, 2007.

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