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CAS Number: 10101-89-0
Synonyms: Sodium phosphate tribasic dodecahydrate; Phosphoric acid trisodium salt dodecahydrate; TSP dodecahydrate; Trisodium orthophosphate dodecahydrate; Sodium phosphate dodecahydrate
Chemical Identity and Properties:
Trisodium phosphate dodecahydrate is an inorganic salt with the molecular formula Na₃PO₄·12H₂O. It has a molecular weight of 380.12 g/mol, of which the water of crystallization accounts for approximately 56.8% (12 moles of water). The compound crystallizes as colorless to white, large prismatic crystals or as a granular powder. It has a density of approximately 1.62 g/cm³ and a melting point of 73.4°C (at which it loses water of crystallization). It is highly soluble in water (approximately 28 g/100 mL at 25°C), and its aqueous solutions are strongly alkaline with a 1% solution having a pH of approximately 12.0. The compound is efflorescent in dry air, gradually losing water to form the hemihydrate or anhydrous form.
Manufacturing Process:
Trisodium phosphate dodecahydrate is produced industrially by the neutralization of phosphoric acid with sodium hydroxide or sodium carbonate:
Reaction: Phosphoric acid (H₃PO₄) is reacted with three equivalents of sodium hydroxide (NaOH) to form trisodium phosphate (Na₃PO₄) and water.
Crystallization: The solution is concentrated and cooled to crystallize the dodecahydrate form.
Separation: The crystals are separated by centrifugation or filtration and may be dried under controlled conditions to maintain the desired hydration state.
Applications:
Heavy-Duty Cleaners and Degreasers: TSP is a classic component of industrial and institutional cleaning formulations, including concrete cleaners, masonry cleaners, engine degreasers, and surface preparation products. Its high alkalinity saponifies fats and oils, enabling effective removal.
Boiler Water Treatment: Used as a water softener and scale inhibitor in boiler systems. It reacts with calcium and magnesium ions to form insoluble phosphates that can be removed by blowdown, preventing scale formation.
Leather Tanning: Employed in the liming process to swell hides and remove hair, as well as a degreasing agent in leather processing.
Pulp and Paper Industry: Used as a bleaching aid, a stain remover, and a processing aid in paper manufacturing.
Sugar Refining: Functions as a clarifying agent in sugar processing, helping to remove impurities and color bodies.
Photographic Chemicals: Used in photographic developers and as a pH buffer in processing solutions.
Food Industry: In some regions and under specific regulatory approvals, anhydrous trisodium phosphate is permitted as a food additive (E339(iii)) as a sequestrant, emulsifier, and pH control agent. However, the dodecahydrate form is primarily used in non-food applications.
Safety and Handling:
Trisodium phosphate dodecahydrate is classified as a corrosive substance:
Skin and Eye Hazard: Causes severe skin burns and eye damage (H314). Contact with eyes can result in severe irritation or corneal damage.
Respiratory Hazard: Inhalation of dust may cause respiratory tract irritation and coughing (H335).
Ingestion: Harmful if swallowed (H302). Ingestion can cause severe gastrointestinal irritation, nausea, vomiting, and diarrhea.
Environmental: May cause alkalinity changes in aquatic environments if released in large quantities.
SAFETY INFORMATION ABOUT TRISODIUM PHOSPHATE DODECAHYDRATE
First aid measures:
Description of first aid measures:
General advice:
Consult a physician.
Show this safety data sheet to the doctor in attendance.
Move out of dangerous area:
If inhaled:
If breathed in, move person into fresh air.
If not breathing, give artificial respiration.
Consult a physician.
In case of skin contact:
Take off contaminated clothing and shoes immediately.
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.
Continue rinsing eyes during transport to hospital.
If swallowed:
Do NOT induce vomiting.
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
Carbon oxides, Nitrogen oxides (NOx), Hydrogen chloride gas
Advice for firefighters:
Wear self-contained breathing apparatus for firefighting if necessary.
Accidental release measures:
Personal precautions, protective equipment and emergency procedures
Use personal protective equipment.
Avoid breathing vapours, mist or gas.
Evacuate personnel to safe areas.
Environmental precautions:
Prevent further leakage or spillage if safe to do so.
Do not let product enter drains.
Discharge into the environment must be avoided.
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:
Avoid inhalation of vapour or mist.
Conditions for safe storage, including any incompatibilities:
Keep container tightly closed in a dry and well-ventilated place.
Containers which are opened must be carefully resealed and kept upright to prevent leakage.
Storage class (TRGS 510): 8A: Combustible, corrosive hazardous materials
Exposure controls/personal protection:
Control parameters:
Components with workplace control parameters
Contains no substances with occupational exposure limit values.
Exposure controls:
Appropriate engineering controls:
Handle in accordance with good industrial hygiene and safety practice.
Wash hands before breaks and at the end of workday.
Personal protective equipment:
Eye/face protection:
Tightly fitting safety goggles.
Faceshield (8-inch minimum).
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.
Full contact:
Material: Nitrile rubber
Minimum layer thickness: 0.11 mm
Break through time: 480 min
Material tested:Dermatril (KCL 740 / Aldrich Z677272, Size M)
Splash contact
Material: Nitrile rubber
Minimum layer thickness: 0.11 mm
Break through time: 480 min
Material tested:Dermatril (KCL 740 / Aldrich Z677272, Size M)
It should not be construed as offering an approval for any specific use scenario.
Body Protection:
Complete suit protecting against chemicals, 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).
Control of environmental exposure
Prevent further leakage or spillage if safe to do so.
Do not let product enter drains.
Discharge into the environment must be avoided.
Stability and reactivity:
Chemical stability:
Stable under recommended storage conditions.
Incompatible materials:
Strong oxidizing agents:
Hazardous decomposition products:
Hazardous decomposition products formed under fire conditions.
Carbon oxides, Nitrogen oxides (NOx), Hydrogen chloride gas.
Disposal considerations:
Waste treatment methods:
Product:
Offer surplus and non-recyclable solutions to a licensed disposal company.
Contact a licensed professional waste disposal service to dispose of this material.
Contaminated packaging:
Dispose of as unused product
