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Silicomolybdic Acid
CAS Number = 11089-20-6
Formula = H4(Mo12SiO40).x H2O
IUPAC Name = 6-hydroxy-1,3,5-trioxa-2λ6,4λ6,6λ5-trimolybdacyclohexane 2,2,4,4,6-pentaoxide;silicic acid
Properties of Silicomolybdic Acid
Molecular Weight 1827.5
Hydrogen Bond Donor Count 8
Hydrogen Bond Acceptor Count 40
Rotatable Bond Count 0
Exact Mass 1825.705530
Monoisotopic Mass 1850.70095
Topological Polar Surface Area 614 Ų
Heavy Atom Count 53
Formal Charge 0
Complexity 1920
Isotope Atom Count 0
Defined Atom Stereocenter Count 0
Undefined Atom Stereocenter Count 0
Defined Bond Stereocenter Count 0
Undefined Bond Stereocenter Count 0
Covalently-Bonded Unit Count 5
Compound Is Canonicalized Yes
Silicomolybdic acid, also known as 12- silicomolybdic acid, is a yellow crystal and its solution is yellow.
It has the same crystal form as phosphomolybdic acid and phosphotungstic acid isomorphic and it will melt at 47 ~ 55 ℃, lose crystal water at 100 ~ 105 ℃.
Its chemical formula is SiO2 • 12MoO3 • xH2O and molecular weight is 1823.36.
Molecular structure is H4SiO4 • 12MoO3 • xH2O and can soluble in water, ethanol, ethyl ether, but can not soluble in benzene and carbon disulfide.
Molybdenum acid is hazardous to the environment, so do not discharge undiluted product to reach ground water, water course or sewage system and without government permission do not allow material discharged into the surrounding environment.
In addition, it should be sealed storage in a cool dry place, if it is used and stored according to specifications will no decomposition.
Anhydrous silicon molybdate production processes: Dry silicomolybdic acid at 40 ℃ to constant weight.
The sample burns at 460 ~ 480 ℃ for 15min for determining the total moisture of partially dehydrated material.
Further, the sample can’t heat to above 500 ℃, because at this temperature, molybdenum trioxide will be full evaporate.
Molybdenum trioxide in anhydrous silicon molybdate volatilized in dry hydrogen chloride gas stream and the residue is impure silica.
The residue should deal with hydrofluoric acid and sulfuric acid and to test the content of silicon dioxide and molybdenum trioxide.
Use methyl orange as indicator to titrate the acid, they equivalent is 485.
Aic offers a wide range of products which includes silicomolybdic acid.
It belongs to acs reagents category.
Silicomolybdic Acid Hydrate is generally immediately available in most volumes.
High purity, submicron and nanopowder forms may be considered.
American Elements produces to many standard grades when applicable, including Mil Spec (military grade); ACS, Reagent and Technical Grade; Food, Agricultural and Pharmaceutical Grade; Optical Grade, USP and EP/BP (European Pharmacopoeia/British Pharmacopoeia) and follows applicable ASTM testing standards.
Uses
Reactant for:
Use in electrostatic synthesis of compounds comprising ultrathin layers of silicododecamolybdate anions and poly(allyl ammonium) cations.
Preparation of charge transfer compounds with Keggin anions and 2,2′-biquinolinium
Silicon is the second most abundant element in the Earth's crust.
Subaerial weathering processes produce orthosilicic acid Si(OH)4 which eventually is deposited in the oceans.
In seawater, various groups of organisms (diatoms, radiolarians, silicoflagellates, sponges and some fungi) utilize silica primarily as a structural component.
The analysis of soluble reactive silica is based upon the formation of yellow silicomolybdic acid from the reaction of ammonium molybdate and silica at low pH.
Phosphate also reacts to produce a positive interference due to the formation of molybdophosphoric acid.
The addition of oxalic acid eliminates the phosphate interference.
The sensitivity of the analysis is increased by a further reduction of the yellow silicomolybdic acid using ascorbic acid, in order to produce "molybdenum blue".
Application
Silicomolybdic acid (Keggin Acid, SMA) can be used to prepare supported acid catalysts for various organic transformations.
For example, it is used to prepare:
SMA immobilized on mesoporous silica spheres for hydrolysis of ammonia borane.
SMA doped carbon-ceramic composite electrodes for electrocatalytic reduction of bromate.
SMA supported on silica gel (SiO2) for Hosomi–Sakurai allylation of carbonyl compounds.
SMA supported on mesoporous SiO2 hollow spheres for Friedel–Crafts alkylation reaction.
Reactant for:
Use in electrostatic synthesis of compounds comprising ultrathin layers of silicododecamolybdate anions and poly(allyl ammonium) cations
Preparation of charge transfer compounds with Keggin anions and 2,2′-biquinolinium
Silicon is the second most abundant element in nature.
Accordingly, it is not surprising that mostwaters contain compounds of silicon, usually as silica (SiO2) or silicates (SiO4– and SiO32–).
Silica concentration in water is commonly less than 30 mg/L, although concentrations greater than 100 mg/L are not unusual; concentrations exceeding 1000 mg/L are possible in brines and brackish water.
Silica and silicates are added to water for a number of uses, such as water conditioners, detergents, and corrosion inhibitors.
However, silica in water can cause significant problems for industries, primarily in boiler and turbine applications.
High pressures and high temperatures cause silica deposits on tubes of boilers and heat exchangers.
These glassy deposits lower the efficiency of heat transfer and lead to premature failure.
Silica deposits on steam turbine blades decrease efficiency and necessitate costly downtime for cleaning.
Silica levels must be kept below 0.005 mg/L in very high pressure applications.
Measuring silica in water is useful when efficiency of demineralizers is monitored.
Testing for silica (one of the first impurities detected when the exchange capacity of a demineralizer is exhausted) provides a sensitive check of demineralizer performance.
Analytical procedures for silica include the Silicomolybdate Method for high range measurement and the Heteropoly Blue Method for low range measurement.
The Heteropoly Blue method is an extension of the Silicomolybdate method to increase sensitivity.
Availability
Special and quality requirements for molybdenum silicon hydroxide oxide are available upon request: silicomolybdic acid is normally available in various concentrations.
SAFETY INFORMATION for Silicomolybdic Acid
Pictograms: Exclamation mark GHS07
Signal Word: Warning
Hazard Statements: H315 - H319 - H335
Precautionary Statements: P261 - P264 - P271 - P280 - P302 + P352 - P305 + P351 + P338
Hazard Classifications: Eye Irrit.
2 - Skin Irrit.
2 - STOT SE 3
Storage Class Code: 10 - Combustible liquids
WGK: WGK 3
Flash Point(F): Not applicable
Flash Point(C):Not applicable
First aid measures
Description of first-aid measures
General advice
If inhaled:
If breathed in, move person into fresh air.
If not breathing, give artificial respiration.
Consult a physician.
In case of skin contact:
Wash off with soap and plenty of water.
Consult a physician.
In case of eye contact:
Rinse thoroughly with plenty of water for at least 15 minutes and consult a physician.
If swallowed:
Never give anything by mouth to an unconscious person.
Rinse mouth with water.
Consult a physician.
Firefighting measures
Extinguishing media
Suitable extinguishing media
Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide.
Special hazards arising from the substance or mixture
Nature of decomposition products not known.
Accidental release measures
Personal precautions, protective equipment and emergency procedures
Use personal protective equipment.
Avoid breathing vapors, mist or gas.
Ensure adequate ventilation.
Evacuate personnel to safe areas.
Environmental precautions
Do not let product enter drains.
Methods and materials for containment and cleaning up
Soak up with inert absorbent material and dispose of as hazardous waste.
Keep in suitable, closed containers for disposal.
Handling and storage
Precautions for safe handling
Advice on safe handling
Avoid contact with skin and eyes.
Avoid inhalation of vapor or mist.
Hygiene measures
Handle in accordance with good industrial hygiene and safety practice.
Wash hands before
breaks and at the end of workday.
Conditions for safe storage, including any incompatibilities
Storage conditions
Keep container tightly closed in a dry and well-ventilated place.
Store in cool place.
Storage class
Storage class (TRGS 510): 10: Combustible liquids
Exposure controls/personal protection
Control parameters
Ingredients with workplace control parameters
Exposure controls
Personal protective equipment
Eye/face protection
Safety glasses with side-shields conforming to EN166 Use equipment for eye protection tested and approved under appropriate government standards such as NIOSH (US) or EN 166(EU).
Skin protection
Handle with gloves.
Gloves must be inspected prior to use.
Use proper glove removal technique (without touching glove's outer surface) to avoid skin contact with this product.
Dispose of contaminated gloves after use in accordance with applicable laws and good laboratory practices.
Wash and dry hands.
The selected protective gloves have to satisfy the specifications of Regulation (EU) 2016/425 and the standard EN 374 derived from it.
Body Protection
Impervious clothing, The type of protective equipment must be selected according to the concentration and amount of the dangerous substance at the specific workplace.
Respiratory protection
Where risk assessment shows air-purifying respirators are appropriate use a fullface respirator with multi-purpose combination (US) or type ABEK (EN 14387) respirator cartridges as a backup to engineering controls.
If the respirator is the sole means of protection, use a full-face supplied air respirator.
Use respirators and components tested and approved under appropriate government standards such as NIOSH (US) or CEN (EU).
The life science business of Merck operates as MilliporeSigma in the US and Canada.
Control of environmental exposure
Do not let product enter drains.
Physical and chemical properties
Information on basic physical and chemical properties
a) Appearance Form: liquid
b) Odor No data available
c) Odor Threshold No data available
d) pH No data available
e) Melting
point/freezing point
No data available
f) Initial boiling point
and boiling range
No data available
g) Flash point No data available
h) Evaporation rate No data available
i) Flammability (solid,
gas)
No data available
j) Upper/lower
flammability or
explosive limits
No data available
k) Vapor pressure No data available
l) Vapor density No data available
m) Density 1,156 g/cm3
Relative density No data available
n) Water solubility No data available
o) Partition coefficient:
n-octanol/water
No data available
p) Autoignition
temperature
No data available
q) Decomposition
temperature
No data available
r) Viscosity Viscosity, kinematic: No data available
Viscosity, dynamic: No data available
s) Explosive properties Not classified as explosive.
t) Oxidizing properties none
Toxicological information
Information on toxicological effects
Mixture
Acute toxicity
Acute toxicity estimate Oral - > 2.000 mg/kg
Acute toxicity estimate Dermal - > 2.000 mg/kg
Additional Information
To the best of our knowledge, the chemical, physical, and toxicological properties have not been thoroughly investigated.
Components
Silicomolybdic acid hydrate
LC50 Inhalation - 4 h - 1,5 mg/l - dust/mist
(Acute toxicity estimate)
LD50 Dermal - 1.100 mg/kg
Ecological information
Toxicity
Results of PBT and vPvB assessment
This substance/mixture contains no components considered to be either persistent, bioaccumulative and toxic (PBT), or very persistent and very bioaccumulative (vPvB) at levels of 0.1% or higher.
Disposal considerations
Waste treatment methods
Product
Offer surplus and non-recyclable solutions to a licensed disposal company.
Waste material must be disposed of in accordance with the Directive on waste 2008/98/EC as well as other national and local regulations.
Leave chemicals in original containers.
No mixing with other waste.
Handle uncleaned containers like the product itself.
Contaminated packaging
Dispose of as unused product.
Transport information
UN number
ADR/RID: - IMDG: - IATA: -
UN proper shipping name
ADR/RID: Not dangerous goods
IMDG: Not dangerous goods
IATA: Not dangerous goods
Transport hazard class(es)
ADR/RID: - IMDG: - IATA: -
Packaging group
ADR/RID: - IMDG: - IATA: -
Environmental hazards
ADR/RID: no IMDG Marine pollutant: no IATA: no
Further information
Not classified as dangerous in the meaning of transport regulations.
Chemical Safety Assessment
For this product a chemical safety assessment was not carried out
Other information
H302 Harmful if swallowed.
H312 Harmful in contact with skin.
H315 Causes skin irritation.
H319 Causes serious eye irritation.
H332 Harmful if inhaled.
H335 May cause respiratory irritation.
Synonyms of Silicomolybdic Acid
12-molybdosilicicacid hydrate
[(hydroxy-dioxo-molybdenio)oxy-dioxo-molybdenio]oxy-dioxo-tris[[[(hydroxy-dioxo-molybdenio)oxy-dioxo-molybdenio]oxy-dioxo-molybdenio]oxy]silyloxy-molybdenum hydrate
cas 11104-89-5 (anhydrous)
