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EC number: 246-805-2 | CAS number: 25306-75-6
- 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
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Dissociation constant
Administrative data
Link to relevant study record(s)
Description of key information
According to “ANNEX IX- STANDARD INFORMATION REQUIREMENTS FOR SUBSTANCES MANUFACTURED OR IMPORTED IN QUANTITIES OF 100 TONNES OR MORE, study for Dissociation constant does not need to be conducted if:
- The substance is readily oxidisable in water.
Expert Judgement
The high water solubility and ionic character identify sodium isobutyl xanthate as a dissociable compound.
Sodium isobutyl xanthate reacts with water and 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.
ROCS2Na + H2O ——→ ROCS2H + NaOH
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 sodium trithiocarbonate to sodium 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.
Therefore testing for Dissociation constant does not need to be performed.
Ref. 1) European Chemicals Agency (ECHA), Guidance for the implementation of REACH, Guidance on information requirements and chemical safety assessment, Chapter R.7a: Endpoint specific guidance, May 2008, pages 168-171.
Key value for chemical safety assessment
Additional information
According to “ANNEX IX- STANDARD INFORMATION REQUIREMENTS FOR SUBSTANCES MANUFACTURED OR IMPORTED IN QUANTITIES OF 100 TONNES OR MORE, study for Dissociation constant does not need to be conducted if:
- The substance is readily oxidisable in water.
Expert Judgement
The high water solubility and ionic character identifysodium isobutyl xanthate as adissociable compound.
Sodium isobutyl xanthate reacts with water and there are three decomposition pathways of xanthates in aqueous solution:
A. Xanthates dissociate forming alkali metal cations and xanthate anions. Thesolution undergoes further hydrolysis to xanthic acid which decomposes intocarbon disulphide and alcohol.
ROCS2Na + H2O——→ROCS2H + NaOH
ROCS2H——→CS2+ ROH
B. Xanthate is oxidised to dixanthogen. The extent of this reaction is very smalland dependent on the pH. Equilibrium is reached after about 5–10% of thexanthate 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 hydrolyticdecomposition.
6ROCS–2+ 3H2O——→6ROH + CO32– + 3CS2+ 2CS32–
Further hydrolysis of sodium trithiocarbonate to sodium carbonate andhydrogen sulphide and carbon disulphide to carbon dioxide and hydrogensulphide may occur. The reaction is catalysed by the alcohol formed from thexanthic acid and is self accelerating.
Reaction C is the main reaction in alkaline solution while A and B occur in acidicsolutions. During use in mining processes, reaction C is the principal decompositionpathway and carbon disulphide the principal decomposition product. Part of thecarbon disulphide formed may decompose further to carbonate and thiocarbonatesalts, 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 belowthe sodium ethyl xanthate solution.
Therefore testing for Dissociation constant does not need to be performed.
Ref. 1) European Chemicals Agency (ECHA), Guidance for the implementation of REACH, Guidance on information requirements and chemical safety assessment, Chapter R.7a: Endpoint specific guidance, May 2008, pages 168-171.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
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