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EC number: 241-922-5 | CAS number: 18015-76-4
- 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
- Type of information:
- other: read across from analogue substance
- Adequacy of study:
- weight of evidence
- Reliability:
- 4 (not assignable)
- Rationale for reliability incl. deficiencies:
- other: see 'Remark'
- Remarks:
- Data from literature; despite the experiment is well documented and scientifically acceptable, some details about the test material and test procedures are missing. Read across from a similar substance which has the same main component and with a different counter ion that does not influence the characteristics related to the specific end-point.
- Principles of method if other than guideline:
- A test tube with glass stopper containing 50 ml of 10 mg/l Malachite Green (MG) solution entirely enclosed by tinfoil was placed in a temperature-controlled reactor. The absorbance variation was measured by UV–vis spectrometer at regular time intervals and degradation intermediates were separated and identified by LC-ESI-MS and GC–MS.
- GLP compliance:
- not specified
- Details on sampling:
- SAMPLE PREPARATION FOR THE DEGRADATION PRODUCTS
The SPE cartridges (Waters Oasis MCX column, 6ml/150 mg) were equilibrated by 3 ml acetonitrile and 3 ml 2 % (V/V) formic acid solution. Next, 10 ml final reaction solutions were loaded through the cartridges at 0.2 ml/min. Subsequently, 2 ml 2 % (V/V) formic acid/acetonitrile solution and 6 ml acetonitrile were added in turn at 2 ml/min to perform washing process. Afterwards, 4 ml 5 % (V/V) ammonium acetate (5 mol/l, pH 7.0)/methanol solution was added at 1ml/min to complete the elution. Finally, the eluents were transferred into rotary evaporator flasks and evaporated at 40 °C until almost dry. The final product was prepared into 1 ml acetonitrile solution and analyzed by LC-ESI–MS. - Details on test conditions:
- A test tube with glass stopper containing 50 ml of 10 mg/l MG solution entirely enclosed by tinfoil was placed in a temperature-controlled reactor. The absorbance variation was measured by UV–vis spectrometer at regular time intervals and degradation intermediates were separated and identified by LC-ESI-MS and GC–MS.
- Duration:
- 40 h
- Initial conc. measured:
- 10 mg/L
- Preliminary study:
- Hydrolysis: 18.80 % after 40 h (rate constant: 0.0192/h; R2= 0.9409)
- Transformation products:
- no
- Details on hydrolysis and appearance of transformation product(s):
- Results from LC–MS identification
Intermediates were detected as follows:
(1) 2.88 min, m/z = 329.4, MG; m/z = 347.3, MG leucocarbinol.
(2) 3.47 min, m/z = 315.4, MG− CH2; 329.4, MG.
(3) 4.37 min, m/z = 331.3, LMG.
(4) 4.80 min, m/z = 329.4, MG; m/z = 361.2, MG + 2OH.
These results conformed to the fact that MG, MG leucocarbinol and LMG can transform naturally to each other in water matrix.
Results from GC–MS identification
The TIC of hydrolysis differed. - % Recovery:
- 81.2
- pH:
- 8
- Duration:
- 40 h
- Remarks on result:
- other: see details in the sections above
- Other kinetic parameters:
- Rate constant kh was 0.0192/h (R2 = 0.9409)
- Details on results:
- After 40 h hydrolysis, 81.20 % of MG was still remaining. Hydrolysis was fit by first-order kinetics model and its apparent rate constant kh was 0.0192/h (R2 = 0.9409). The spectra variation shows no blue shift of the major peaks at about 315 nm, 425 nm, and 618 nm, but the peaks exhibit a slight decrease trend. Meanwhile a slight increase trend between 200 nm and 280 nm is observable, indicating the slight increase trend of benzene rings and conjugated structure with double bonds. This observation is consistent with the LC–MS results.
Based on the structure of MG, the triarylmethyl cation is stabilized by the conjugation that delocalizes the positive charge and Cl− is a good leaving group. Therefore, the hydrolysis mechanism should be SN1 mechanism and the reaction rate is unrelated to the concentration of the nucleophile H2O.
MG+Cl- → MG+ + Cl-
MG+ + H2O → MGOH + H+
The pH varied from 8.98 to 7.87 in the reaction process, which conformed to the presumption above. - Conclusions:
- Hydrolysis: 18.80 % after 40 h (rate constant: 0.0192/h; R2= 0.9409)
MG, MG leucocarbinol and LMG can transform naturally to each other in water matrix. - Executive summary:
A test tube with glass stopper containing 50 ml of 10 mg/l Malachite Green (MG) solution entirely enclosed by tinfoil was placed in a temperature-controlled reactor. The absorbance variation was measured by UV–vis spectrometer at regular time intervals and degradation intermediates were separated and identified by LC-ESI-MS and GC–MS.
After 40 h hydrolysis, 81.20 % of MG was still remaining. Hydrolysis was fit by first-order kinetics model and its apparent rate constant kh was 0.0192/h (R2 = 0.9409). The spectra variation shows no blue shift of the major peaks at about 315 nm, 425 nm, and 618 nm, but the peaks exhibit a slight decrease trend. Meanwhile a slight increase trend between 200 nm and 280 nm is observable, indicating the slight increase trend of benzene rings and conjugated structure with double bonds. This observation is consistent with the LC–MS results. Based on the structure of MG, the triarylmethyl cation is stabilized by the conjugation that delocalizes the positive charge and Cl− is a good leaving group. Therefore, the hydrolysis mechanism should be SN1 mechanism and the reaction rate is unrelated to the concentration of the nucleophile H2O. The pH varied from 8.98 to 7.87 in the reaction process, which conformed to the presumption above.
Results from LC–MS conformed to the fact that MG, MG leucocarbinol and LMG can transform naturally to each other in water matrix.
Conclusion
Hydrolysis: 18.80 % after 40 h (rate constant: 0.0192/h; R2= 0.9409)
MG, MG leucocarbinol and LMG can transform naturally to each other in water matrix.
- Endpoint:
- hydrolysis
- Type of information:
- experimental study
- Adequacy of study:
- weight of evidence
- Reliability:
- 4 (not assignable)
- Rationale for reliability incl. deficiencies:
- other: Data from literature; despite the global experiment is well documented and scientifically acceptable, the hydrolysis determination part of study miss of some information and details.
- Principles of method if other than guideline:
- Data taken from an experiment of photodegradation. Hydrolysis experiments were performed using 250 ml amber glass bottles, which were kept in the dark during the tests and the substance decrease from the initial concentration was measured.
- GLP compliance:
- not specified
- Radiolabelling:
- no
- Preliminary study:
- A 45 % decrease in initial MG concentration was observed in 145 hours, showing that a part of MG degradation is due to hydrolysis.
- Transformation products:
- no
- Remarks on result:
- other: see details in the sections
- Remarks on result:
- other: see details in the sections
- Conclusions:
- A 45 % decrease in initial MG concentration was observed in 145 hours, showing that a part of MG degradation is due to hydrolysis.
- Executive summary:
Data obtained in combination with an experiment of photodegradation (see 5.1.3 phototransformation in water).
Hydrolysis experiments were performed using 250 ml amber glass bottles, which were kept in the dark during the tests and the substance decrease from the initial concentration was measured.
A 45 % decrease in initial Malachite Green Oxalate (MGO) concentration was observed in 145 hrs, showing that a part of MGO degradation is due to hydrolysis.
Referenceopen allclose all
Description of key information
Malachite Green Oxalate (MGO), hydrolysis t1/2 (45%) ca. 145h in dark conditions, ambient temperature
Key value for chemical safety assessment
Additional information
A 45 % decrease in initial Malachite Green Oxalate (MGO) concentration was observed in 145 hours under dark conditions, showing that an important part of MGO degradation is due to hydrolysis (Pérez-Estrada et al., 2008).
Further data, obtained in combination with an experiment of photodegradation, showed that MG hydrolysis reaction after 40 h was 18.80 %; hydrolysis was fit by first-order kinetics model and its apparent rate constant kh was 0.0192/h (R2 = 0.9409). Based on the structure of MG, the triarylmethyl cation is expected to be stabilized by the conjugation that delocalizes the positive charge and a good leaving group. Therefore, the hydrolysis mechanism should be SN1 mechanism and the reaction rate is unrelated to the concentration of the nucleophile H2O. The pH varied from 8.98 to 7.87 in the reaction process. Results from LC–MS confirmed to the fact that MG, MG leucocarbinol and Leucomalachite Green can transform naturally to each other in water matrix (Yong et al., 2015).
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