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EC number: 220-329-5 | CAS number: 2720-73-2
- Life Cycle description
- Uses advised against
- Endpoint summary
- Appearance / physical state / colour
- Melting point / freezing point
- Boiling point
- Density
- Particle size distribution (Granulometry)
- Vapour pressure
- Partition coefficient
- Water solubility
- Solubility in organic solvents / fat solubility
- Surface tension
- Flash point
- Auto flammability
- Flammability
- Explosiveness
- Oxidising properties
- Oxidation reduction potential
- Stability in organic solvents and identity of relevant degradation products
- Storage stability and reactivity towards container material
- Stability: thermal, sunlight, metals
- pH
- Dissociation constant
- Viscosity
- Additional physico-chemical information
- Additional physico-chemical properties of nanomaterials
- Nanomaterial agglomeration / aggregation
- Nanomaterial crystalline phase
- Nanomaterial crystallite and grain size
- Nanomaterial aspect ratio / shape
- Nanomaterial specific surface area
- Nanomaterial Zeta potential
- Nanomaterial surface chemistry
- Nanomaterial dustiness
- Nanomaterial porosity
- Nanomaterial pour density
- Nanomaterial photocatalytic activity
- Nanomaterial radical formation potential
- Nanomaterial catalytic activity
- Endpoint summary
- Stability
- Biodegradation
- Bioaccumulation
- Transport and distribution
- Environmental data
- Additional information on environmental fate and behaviour
- Ecotoxicological Summary
- Aquatic toxicity
- Endpoint summary
- Short-term toxicity to fish
- Long-term toxicity to fish
- Short-term toxicity to aquatic invertebrates
- Long-term toxicity to aquatic invertebrates
- Toxicity to aquatic algae and cyanobacteria
- Toxicity to aquatic plants other than algae
- Toxicity to microorganisms
- Endocrine disrupter testing in aquatic vertebrates – in vivo
- Toxicity to other aquatic organisms
- Sediment toxicity
- Terrestrial toxicity
- Biological effects monitoring
- Biotransformation and kinetics
- Additional ecotoxological information
- Toxicological Summary
- Toxicokinetics, metabolism and distribution
- Acute Toxicity
- Irritation / corrosion
- Sensitisation
- Repeated dose toxicity
- Genetic toxicity
- Carcinogenicity
- Toxicity to reproduction
- Specific investigations
- Exposure related observations in humans
- Toxic effects on livestock and pets
- Additional toxicological data
Hydrolysis
Administrative data
Link to relevant study record(s)
- Endpoint:
- hydrolysis
- Data waiving:
- study scientifically not necessary / other information available
- Justification for data waiving:
- the study does not need to be conducted because the substance is readily biodegradable
- other:
- Endpoint:
- hydrolysis
- Type of information:
- experimental study
- Adequacy of study:
- weight of evidence
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- comparable to guideline study with acceptable restrictions
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 111 (Hydrolysis as a Function of pH)
- GLP compliance:
- not specified
- Radiolabelling:
- no
- Analytical monitoring:
- not specified
- Preliminary study:
- Hydrolysis will be a significant factor in determining the environmental fate of Potassium amyl xanthate. In neutral or mildly alkaline solutions, Potassium amyl xanthate decomposes to the alcohol, carbon disulphide, potassium carbonate and potassium trithiocarbonate, the two salts arising from neutralisation of carbon disulphide with the potassium hydroxide liberated. In more strongly alkaline media, hydrogen sulphide is liberated. However, strongly alkaline conditions are unlikelyto be encountered under the conditions of use in the mining industry. The half-life atpH 7 at 25°C is reportedly about 260 hours, increasing to over 500 hours in the pH range 8 to 11.
Potassium amyl xanthate is hydrolytically unstable when exposed to acidic conditions, reverting rapidly to amyl alcohol, carbon disulphide and potassium hydroxide, and therefore will not persist in the acidic environment of tailings dams. If dischargedto waterways, the chemical would be likely to persist for at least some days,hydrolysing only slowly in this more neutral environment. However, it is notexpected to bioaccumulate in view of its ionic character. - Transformation products:
- yes
- No.:
- #1
- No.:
- #2
- No.:
- #3
- No.:
- #4
- Details on hydrolysis and appearance of transformation product(s):
- In neutral and alkaline media, xanthates decompose by hydrolytic decomposition.
6ROCS–2 + 3H2O →6ROH + CO3 2 – + 3CS2 + 2CS3 2 –
Further hydrolysis of potassium trithiocarbonate to potassium carbonate and hydrogen sulphide and carbon disulphide to carbon dioxide and hydrogen sulphide may occur. The reaction is catalysed by the alcohol formed from the xanthic acid and is self accelerating.
Reaction C is the main reaction in alkaline solution while A and B occur in acidic solutions. During use in mining processes, reaction C is the principal decomposition pathway and carbon disulphide the principal decomposition product.
Part of the carbon disulphide formed may decompose further to carbonate and thiocarbonate salts, some of it may evaporate and some may build up in the xanthate solution. Once the solubility of carbon disulphide is exceeded it forms a separate layer below the potassium amyl xanthate solution.
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. - pH:
- 7
- Temp.:
- 25 °C
- DT50:
- 260 h
- Type:
- other: abiotic
- pH:
- 11
- Temp.:
- 25 °C
- DT50:
- 500 h
- Type:
- other: abiotic
- Details on results:
- Hydrolysis will be a significant factor in determining the environmental fate of potassium amyl xanthate. In neutral or mildly alkaline solutions, potassium amyl xanthate decomposes to the alcohol, carbon disulphide, potassium carbonate and potassium trithiocarbonate, the two salts arising from neutralisation of carbon disulphide with the potassium hydroxide liberated. In more strongly alkaline media, hydrogen sulphide is liberated. However, strongly alkaline conditions are unlikely to be encountered under the conditions of use in the mining industry. The half-life at pH 7 at 25°C is reportedly about 260 hours, increasing to over 500 hours in the pH range 8 to 11
- Validity criteria fulfilled:
- yes
- Conclusions:
- The half-life at pH 7 at 25°C is reportedly about 260 hours, increasing to over 500 hours in the pH range 8 to 11
- Executive summary:
Hydrolysis will be a significant factor in determining the environmental fate of Potassium amyl xanthate. In neutral or mildly alkaline solutions, Potassium amyl xanthate decomposes to the alcohol, carbon disulphide, potassium carbonate and potassium trithiocarbonate, the two salts arising from neutralisation of carbon disulphide with the potassium hydroxide liberated. In more strongly alkaline media, hydrogen sulphide is liberated. However, strongly alkaline conditions are unlikelyto be encountered under the conditions of use in the mining industry. The half-life atpH 7 at 25°C is reportedly about 260 hours, increasing to over 500 hours in the pH range 8 to 11.
Potassium amyl xanthate is hydrolytically unstable when exposed to acidic conditions, reverting rapidly to amyl alcohol, carbon disulphide and potassium hydroxide, and therefore will not persist in the acidic environment of tailings dams. If dischargedto waterways, the chemical would be likely to persist for at least some days,hydrolysing only slowly in this more neutral environment. However, it is notexpected to bioaccumulate in view of its ionic character.
Referenceopen allclose all
Description of key information
Hydrolysis will be a significant factor in determining the environmental fate of Potassium amyl xanthate. In neutral or mildly alkaline solutions, Potassium amyl xanthate decomposes to the alcohol, carbon disulphide, potassium carbonate and potassium trithiocarbonate, the two salts arising from neutralisation of carbon disulphide with the potassium hydroxide liberated. In more strongly alkaline media, hydrogen sulphide is liberated. However, strongly alkaline conditions are unlikelyto be encountered under the conditions of use in the mining industry. The half-life atpH 7 at 25°C is reportedly about 260 hours, increasing to over 500 hours in the pH range 8 to 11.
Potassium amyl xanthate is hydrolytically unstable when exposed to acidic conditions, reverting rapidly to amyl alcohol, carbon disulphide and potassium hydroxide, and therefore will not persist in the acidic environment of tailings dams. If dischargedto waterways, the chemical would be likely to persist for at least some days,hydrolysing only slowly in this more neutral environment. However, it is notexpected to bioaccumulate in view of its ionic character.
Key value for chemical safety assessment
- Half-life for hydrolysis:
- 260 h
- at the temperature of:
- 25 °C
Additional information
Hydrolysis is a chemical reaction during which molecules of water (H2O) are split into hydrogen cations (H+, conventionally referred to as protons) and hydroxide anions (OH−) in the process of a chemical mechanism).
When water is added to potassium amyl xanthate it reacts with water to form the others substances: alcohol, potassium carbonate, trithiocarbonate and carbon disulphide.
On this basis, Potassium amyl xanthate does not have a potential for Hydrolysis and potassium ion will not hydrolise.
On the other basis hydrolysis may proceed with the others active substances:
Further hydrolysis of potassium trithiocarbonate to potassium carbonate and hydrogen sulphide and carbon disulphide to carbon dioxide and hydrogen sulphide may occur. The reaction is catalysed by the alcohol formed from the xanthic acid and is self accelerating.
On this basis hydrolysis proceed with the others active substances: potassium trithiocarbonate, carbon disulphide, hydrogen sulphide.
Xanthates decompose in aqueous solution by dissociation, oxidation and hydrolysis. Hydrolytic decomposition is the main reaction in alkaline solutions while the other two reactions occur in acidic solutions.
Aqueous solution
There are three decomposition pathways of xanthates in aqueous solution:
A. Xanthates dissociate forming alkali metal cations and xanthate anions. The solution undergoes further hydrolysis to xanthic acid which decomposes into carbon disulphide and alcohol.
ROCS2K + H2O → ROCS2H + KOH
ROCS2H → CS2 + ROH
B. Xanthate is oxidised to dixanthogen. The extent of this reaction is very small and dependent on the pH. Equilibrium is reached after about 5–10% of the xanthate is oxidised, and the reaction increases with a fall in the pH.
2ROCS–2 + H2O + _O2 →(ROCS2)2 + 2OH–
C. In neutral and alkaline media, xanthates decompose by hydrolytic decomposition.
6ROCS–2 + 3H2O →6ROH + CO3 2 – + 3CS2 + 2CS3 2 –
Further hydrolysis of potassium trithiocarbonate to potassium carbonate and hydrogen sulphide and carbon disulphide to carbon dioxide and hydrogen sulphide may occur. The reaction is catalysed by the alcohol formed from the xanthic acid and is self accelerating.
Reaction C is the main reaction in alkaline solution while A and B occur in acidic solutions. During use in mining processes, reaction C is the principal decomposition pathway and carbon disulphide the principal decomposition product.
Part of the carbon disulphide formed may decompose further to carbonate and thiocarbonate salts, some of it may evaporate and some may build up in the xanthate solution. Once the solubility of carbon disulphide is exceeded it forms a separate layer below the potassium amyl xanthate solution.
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.
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