Phosphoric acid

  • White phosphoric acid
  • Orthophosphoric acid
  • Amberphos 54
  • 3M Etching Liquid
  • Ultra-Etch Gel
  • WC-Reiniger
Formula
H3PO4
Structure
Description
Colorless, odorless, syruppy liquid.
Uses
Polymer gasoline catalyst, etchant (semiconductor manufacture), acidulant (soft drinks, prepared foods), aluminum brighteninganodizing agent, aluminumsteelmagnesiumzinc anticorrosion treatment reagent, microbial fermentation nutrient, refractories raw material.

Registry Numbers and Inventories.
CAS
7664-38-2
EC (EINECS/ELINCS)
231-633-2
EC Index Number
015-011-00-6
EC Class
Corrosive
RTECS
TB6300000
RTECS class
Mutagen; Human Data; Primary Irritant
UN (DOT)
1805
Merck
12,7500
Beilstein/Gmelin
2000 (G)
EPA OPP
76001
Swiss Giftliste 1
G-9514
Canada DSL/NDSL
DSL
US TSCA
Listed
Austrailia AICS
Listed
New Zealand
Listed
Japan ENCS (MITI)
Listed
Korea ECL
Listed

Properties.
Formula
H3O4P
Formula mass
98.0
Melting point, °C
21
Boiling point, °C
158
Vapor pressure, mmHg
0.01 (130 C)
Vapor density (air=1)
3.4
Odor Threshold Odor threshold Odorless
Density
1.541 g/cm3
Solubility in water
Very soluble
Viscosity
3.86 cp (40% solution at 20C).
Surface tension
74.6 erg/cm2 (20 C)
Refractive index
1.3420 (20 C)
pKa/pKb
1.97 (pKa)
Partition coefficient, pKow
-2.15
Heat of fusion
10.6 kJ/mol

Hazards and Protection.
Storage
May be stored in suitable stainless steel containers. (Hot acid attacks porcelain and graniteware).
E
Handling
Containers of this material may be hazardous when emptied. Since emptied containers retain product residues (vapor, liquid, and/or solid), all hazard precautions given in the data sheet must be observed. Addition to water releases heat which can result in violent boiling and spattering. Always add slowly and in small amounts. Never use hot water. Never add water to acids. Always add acids to water.
Protection
Wear appropriate protective gloves, clothing and goggles.
Respirators
Wear positive pressure self-contained breathing apparatus (SCBA).
Small spills/leaks
Keep material out of water sources and sewers. Build dikes to contain flow as necessary. Neutralize spilled material with crushed limestone, soda ash, or lime. Apply water spray or mist to knock down vapors. Vapor knockdown water is corrosive or toxic and should be diked for containment. Land spill: Dig a pit, pond, lagoon, holding area to contain liquid or solid material. Dike surface flow using soil, sand bags, foamed polyurethane, or foamed concrete. Absorb bulk liquid with fly ash or cement powder. Neutralize with agricultural lime (CaO), crushed limestone (CaCO3) or sodium bicarbonate (NaHCO3). Water spill: Neutralize with agricultural lime (CaO), crushed limestone (CaCO3), or sodium bicarbonate (NaHCO3). Adjust pH to neutral (pH=7). Use mechanical dredges or lifts to remove immobilized masses of pollutants and precipitates.
Stability
Stable.
Incompatibilities
Reacts exothermically with bases May react with active metals, including such structural metals as aluminum and iron, to release hydrogen, a flammable gas Reacts with cyanide compounds to release gaseous hydrogen cyanide Reacts violently with sodium tetrahydroborate.
Decomposition
Oxides of phosphorus are formed during thermal decomposition. Decomposition products: converted to pyrophosphoric acid (H4P2O7) when heated to 213 C.

Fire.
Fire fighting
Extinguish fire using agent suitable for type of surrounding fire. (Material itself does not burn or burns with difficulty.) Use water in flooding quantities as fog. Cool all affected containers with flooding quantities of water. Apply water from as far a distance as possible.
Fire potential
May heat combustibles to ignition point.
Hazards
Some are oxidizers and may ignite combustibles (wood, paper, oil, clothing, etc.). Contact with metals may evolve flammable hydrogen gas. Containers may explode when heated.
Combustion products
Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes.
Health
2
 
Flammability
0
 
 
Reactivity
0
 

Health.
Exposure limit(s)
OSHA PEL: TWA 1 mg/m3 NIOSH REL: TWA 1 mg/m3 ST 3 mg/m3 NIOSH IDLH: 1000 mg/m3
Poison_Class
5
Exposure effects
Coma and seizures have occurred.
   Ingestion
Irritation or burns of the oropharynx, esophagus, or gi tract may occur following ingestion. Nausea, vomiting, abdominal pain, hematemesis, bloody diarrhea, and perforation with severe burns may be noted.
   Inhalation
Respiratory tract irritation and coughing may develop. Aspiration pneumonitis has occurred.
   Skin
Dermal irritation or burns may develop.
   Eyes
Eyes, nose, and throat irritation may occur.

First aid
 
   Ingestion
Seek medical assistance.
   Inhalation
Move victim to fresh air. Apply artificial respiration if victim is not breathing. Do not use mouth-to-mouth method if victim ingested or inhaled the substance; induce artificial respiration with the aid of a pocket mask equipped with a one-way valve or other proper respiratory medical device. Administer oxygen if breathing is difficult.
   Skin
Remove contaminated clothing and wash exposed area thoroughly with soap and water. A physician should examine the area if irritation or pain persists.
   Eyes
Irrigate exposed eyes with copious amounts of tepid water for at least 15 minutes. If irritation, pain, swelling, lacrimation, or photophobia persist, the patient should be seen in a health care facility.

Transport.
UN number
1805
Response guide
Hazard class
8
Packing Group
III
 
USCG CHRIS Code
PAC
 
1 Non-oxidizing mineral acids
Std. Transport #
4930248 4930247 4930249
 
IMO Chemical Code
17
IMO Pollution Category
D
IMO Hazard code
S