PRODUCTS

PHOSPHINE OXIDE

Phosphine oxide, or Phosphinic acid, is a phosphorus oxyacid and a powerful reducing agent with molecular formula H3PO2.
Phosphine oxide is a colorless low-melting compound, which is soluble in water, dioxane, and alcohols.
Phosphine oxide is used in articles, in formulation or re-packing, at industrial sites and in manufacturing.

CAS Number: 6303-21-5
EC Number: 228-601-5
Chemical Frmula: H3PO2
Molar Mass: 66.00 g/mol

Synonyms: 12164-97-5 [RN], 228-601-5 [EINECS], hydroxyphosphanone, MFCD02183592 [MDL number], Phosphenous acid [ACD/Index Name], Phosphinic acid [ACD/Index Name] [ACD/IUPAC Name], phosphinic-acid, phosphorus dioxide, Phosphorus oxide (PO2), 10039-56-2 [RN], 15460-68-1 [RN], 60062-19-3 [RN], 68412-68-0 [RN], 68412-69-1 [RN], 7789-79-9 [RN], HOPO, HPA, HPH2O2, hydrophosphorous acid, hydroxidooxidophosphorus, hydroxyl phosphine oxide, Hydroxyphosphine oxide, hypophosphite [Wiki], HYPOPHOSPHITE ION, Hypophosphoric acid [ACD/Index Name], Phosphine oxide, hydroxy-, PHOSPHINYLOXY, phosphorus(IV) oxide, Hypophosphorous acid [NF] [Wiki], 6303-21-5 [RN], Acide phosphinique [French] [ACD/IUPAC Name], H2PO(OH) [Formula], Hypophosphorous acid (VAN), PH2(OH)O [Formula], PH2O(OH) [Formula], Phosphinic acid [ACD/Index Name] [ACD/IUPAC Name], Phosphinsäure [German] [ACD/IUPAC Name], [PH2(OH)O], [PH2O(OH)], dihydridodioxophosphoric acid, dihydridohydroxidooxidophosphorus, dihydroxyphosphanium, dihydroxyphosphonium, H3PO2, HPA, hydrophosphorous acid, Hypophosphorous acidmissing, MFCD02183592 [MDL number], UNII-8B1RL9B4ZJ, 次磷酸 [Chinese]

Phosphine oxide is an ingredient to many etching solutions, such as solutions for etching of Al (Aluminum), GaAs (gallium arsenide), InP (indium phosphide), Ag (silver) or ZnO (zinc oxide).
Very hot concentrated phosphoric acid can also be used for etching of SiNx (silicon nitride).

Phosphine oxide is a phosphorus oxoacid and a powerful reducing agent.
Inorganic chemists refer to the free acid by this name (also as "HPA") although Phosphine oxide official IUPAC name is Phosphine oxide.

Phosphine oxide is a colorless low-melting compound, which is soluble in water, dioxane, and alcohols.
The formula for Phosphine oxide is generally written H3PO2, but a more descriptive presentation is HOP(O)H2 which highlights Phosphine oxide monoprotic character.
Salts derived from this acid are called hypophosphites.

HOP(O)H2 exists in equilibrium with the minor tautomer HP(OH)2.
Sometimes the minor tautomer is called Phosphine oxide and the major tautomer is called Phosphine oxide.

Phosphine oxide derivatives exhibit diverse biological activities and a high degree of structural diversity, rendering them a versatile tool in the development of new medicinal agents.

Phosphine oxide is an oxoacid of phosphorus.
Phosphine oxide chemical formula is H3PO2.

Phosphine oxide also known as Phosphinic acid is a phosphorous oxoacid and also acts as a good reducing agent.
Phosphine oxide is basically a colourless aqueous solution that is soluble in water, dioxin as well as in alcohol.

Phosphine oxide formula is H3PO2 is a neutral molecule with no spare charge on it.
Thus the oxidation number of the central atom phosphorus is +1 which can be described as follows.

As the whole charge on the H3PO2 molecule is zero.
Charge on a single hydrogen atom is one and there are three atoms present in the molecules that make Phosphine oxide 3.

Similarly, the valency of a single oxygen atom is (-2) and there are 2 oxygen atoms present in the molecule.
Thus the formula would be considering the oxidation state of the phosphorus atom as unknown as therefore represented as X.
1x31x3 + X +(−2)x2 (−2)x2 = 3 - 4 + X = -1 + X or, X = 1.

Phosphine oxide formula that has a more precise and descriptive presentation as HOP(O)H2 which is the actual Phosphine oxide chemical formula that actually represents the monoprotic characteristics by the later molecular formula.

HOP(O)H2 is in equilibrium with the minor structural formula of Phosphine oxide that is interconvertible like HP(OH)2.
The minor tautomers are referred to as Phosphine oxide and the major monomers are called Phosphine oxide.

Phosphine oxide compounds (phosphinates) are derivatives of Phosphine oxide H 2 P(O)(OH).
Phosphine oxide peptides (phosphinic pseudopeptides) are peptide isosteres where one peptide bond is substituted by the nonhydrolysable phosphinate moiety -P(O)(OH)-CH 2 - or -P(O)(OH)-.

This substitution represents a very convenient mimic of a substrate in the transition state for at least two distinct classes of hydrolytic enzymes, Zn-metalloproteinases and aspartic acid proteinases.

These proteins are mainly proteinases, however other types of proteins such as transferases, synthetases, ligases or even receptors are also discussed.
Genome sequencing projects have been identifying protein sequences faster than Phosphine oxide is possible to discover their functions.

The development of combinatorial chemistry in the past few years has boosted up the interest in the use of chemistry to address biological problems.
Phosphinates, especially in conjunction with combinatorial chemistry approaches, represent an extremely versatile tool in the search for proteome and Phosphine oxide function.

Phosphine oxide is registered under the REACH Regulation and is manufactured in and / or imported to the European Economic Area, at ≥ 100 to < 1 000 tonnes per annum.
Phosphine oxide is used in articles, in formulation or re-packing, at industrial sites and in manufacturing.

Phosphine oxide (HPA), or Phosphine oxide, is a phosphorus oxyacid and a powerful reducing agent with molecular formula H3PO2.
Phosphine oxide is a colorless low-melting compound, which is soluble in water, dioxane, and alcohols.

Phosphine oxide, or Phosphine oxide, is a phosphorus oxyacid and a powerful reducing agent with molecular formula H3PO2.
Phosphine oxide is a colorless low-melting compound, which is soluble in water, dioxane and alcohols.

The formula for this acid is generally written H3PO2, but a more descriptive presentation is HOP(O)H2, which highlights Phosphine oxide monoprotic character.
Salts derived from this acid are called hypophosphites.

HOP(O)H2 exists in equilibrium with the minor tautomer HP(OH)2.
Sometimes the minor tautomer is called Phosphine oxide and the major tautomer is called Phosphine oxide.

The formula for Phosphine oxide is generally written H3PO2, but a more descriptive presentation is HOP(O)H2, which highlights Phosphine oxide monoprotic character.
Salts derived from Phosphine oxide are called hypophosphites.

HOP(O)H2 exists in equilibrium with the minor tautomer HP(OH)2.
Sometimes the minor tautomer is called Phosphine oxide and the major tautomer is called Phosphine oxide.

Phosphine oxide is a phosphorus oxoacid that consists of a single pentavalent phosphorus covalently bound via single bonds to two hydrogens and a hydroxy group and via a double bond to an oxygen.J
Phosphine oxide has role antioxidant.

Phosphine oxide is a phosphorus oxoacid.
Phosphine oxide is conjugate acid of phosphinate.

Phosphine oxide is a powerful reducing agent with a molecular formula of H3PO2.
Inorganic chemists refer to the free acid by this name although Phosphine oxide IUPAC name is dihydridohydroxidooxidophosphorus, or the acceptable name of Phosphine oxide.

In organic chemistry, H3PO2 best known for their use in the reduction of arenediazonium salts, converting ArN2+ to Ar-H.
When diazotized in a concentrated solution of Phosphine oxide, an amine substituent can be removed from arenes, selectively over alkyl amines.

Phosphine oxide (HPA) is also known as Phosphine oxide, hydroxy(oxo)-λ5-phosphane, oxo-λ5-phosphinous acid and oxo-λ5-phosphanol.
Phosphine oxide molecular formula is H3PO2 or HOP(O)H2.

Phosphine oxide is a hydroxy phosphine oxide or phosphorus oxyacid having a monobasic character.
Phosphine oxide is a low-melting colorless compound, which is highly soluble in alcohols, dioxane and water.

Hypophosphoric acid is a mineral acid with the formula H4P2O6, with phosphorus in a formal oxidation state of +4.
In the solid state Phosphine oxide is present as the dihydrate, H4P2O6·2H2O.
In hypophosphoric acid the phosphorus atoms are identical and joined directly with a P−P bond.

Isohypophosphoric acid is a structural isomer of hypophosphoric acid in which one phosphorus has a hydrogen directedly bonded to Phosphine oxide and that phosphorus atom is linked to the other one by an oxygen bridge to give a phosphorous acid/phosphoric acid mixed anhydride.
The two phosphorus atoms are in the +3 and +5 oxidation states, respectively.

Phosphine oxide is a phosphorus oxoacid and a member of Phosphine oxides.
Phosphine oxide is a conjugate acid of a phosphinate.

Phosphine oxide is an important chemical product with wide applications in pharmaceuticals and electroless plating.

Free Phosphine oxide is prepared by acidifying aqueous solutions of hypophosphite ions, H2PO2−.
For example, the solution remaining when phosphine is prepared from the reaction of white phosphorus and a base contains the H2PO2− ion.
If barium hydroxide (BaOH) is used as the base and the solution is acidified with sulfuric acid, barium sulfate, BaSO4, precipitates, and an aqueous solution of Phosphine oxide results.

Ba2+ + 2H2PO2− + 2H3O+ + SO42− → BaSO4 + 2H3PO2 + 2H2O

The pure acid cannot be isolated merely by evaporating the water, however, because of the easy oxidation of the phosphoric acids (and elemental phosphorus) and Phosphine oxide disproportionation to phosphine and phosphorous acid.
The pure acid can be obtained by extraction of Phosphine oxide aqueous solution by diethyl ether, (C2H5)2O.

Pure Phosphine oxide forms white crystals that melt at 26.5 °C (79.7 °F).

The electronic structure of Phosphine oxide is such that Phosphine oxide has only one hydrogen atom bound to oxygen, and Phosphine oxide is thus a monoprotic oxyacid.
Phosphine oxide is a weak acid and forms only one series of salts, the hypophosphites.
Hydrated sodium hypophosphite, NaH2PO2 · H2O, is used as an industrial reducing agent, particularly for the electroless plating of nickel onto metals and nonmetals.

Applications of Phosphine oxide:
Phosphine oxide (and Phosphine oxide salts) are used to reduce metal salts back into bulk metals.
Phosphine oxide is effective for various transition metals ions (i.e. those of: Co, Cu, Ag, Mn, Pt) but is most commonly used to reduce nickel.

This forms the basis of electroless nickel plating (Ni–P), which is the single largest industrial application of hypophosphites.
For this application Phosphine oxide is principally used as a salt (sodium hypophosphite).

Phosphine oxide is primarily used for electroless nickel plating.
Phosphine oxide is involved in the reduction of arenediazonium salts.

Phosphine oxide acts as an additive in Fischer esterification reactions.
Also, Phosphine oxide serves as a neutralizing agent, antioxidant, catalyst in polymerization and poly condensation, and wetting agent.

Further, Phosphine oxide is used in the formulation of pharmaceuticals, discoloration of polymers, water treatment and retrieval of precious or non-ferrous metals.
In addition to this, Phosphine oxide is used as bleaching agents for plastics, synthetic fibers, decolorizing agent and for color stabilization during the manufacture of chemicals and several plastics.

Phosphine oxide is used as a pharmaceutical additive as antioxidant, as an ingredient of electroless plating solutions, for the retrieval of precious or non-ferrous metals as a water treatment agent, as a meat preservative to prevent the discoloration of polymers and for the production of chemicals

Uses of Phosphine oxide:
Phosphine oxide is used as a chain transfer agent in aqueous polymerizations.
Phosphine oxide has color stabilizer function, antioxydant property and Phosphine oxide is also used as reducer or catalyst in multiple industries.

Phosphine oxide is used in the formulation of pharmaceuticals, discoloration of polymers, water treatment, retrieval of precious or non-ferrous metals.
Phosphine oxide main use is for electroless plating, i.e. deposition of metal films from solution.

Phosphine oxide is majorly manufactured from Sodium Hypophosphite.
Phosphine oxide is widely used as a reducing agent to reduce Cu, Hg and Ag etc. to verify impurities, such as Nb, As and Ta, etc.

Phosphine oxide is also used as a catalyst during esterification and in medicines, Phosphine oxide is used to detect tellurium and arsenic, etc
Phosphine oxide is used as a decolorizing or bleaching agent in plastics, chemicals and synthetic fibers.
Phosphine oxide is also used as a color stabilizer during the manufacturing of chemicals and plastics, including polyamides, nylon fibers, polyacrilonitrile, polyester fiber, epoxies, glycerols, fatty acid esters and alkyd resins.

Phosphine oxide is also used as a polycondensation and polymerization agent, reducing agent, an antioxidant and stimulant in pharmaceuticals, etc.
Thus, due to the wide areas of application of Phosphine oxide, Phosphine oxide consumption is expected to grow at a significant rate during the forecast period.

Phosphine oxide is used in various end use industries, such as building and construction, electronics and electrical, chemical and plastics, etc.
Thus, owing to the growing use of Phosphine oxide in various industries, Phosphine oxide sales is expected to increase, thereby propelling the growth of the global Phosphine oxide market during the forecast period.

Phosphine oxide is used as reducing agent for electroless plating.
Phosphine oxide can be used to prevent discoloration of phosphoric acid resin.

Phosphine oxide is used as esterification catalyst, the refrigerant.
Phosphine oxide is used to produce hypophosphite, sodium salts, manganese salts, iron salts are generally used as nourishing substances.

Phosphine oxide is used in medicine and as reducing agent, the determination of arsenic, tellurium and separation of tantalum, niobium and other reagents.
Phosphine oxide is strong reducing agent, Phosphine oxide can be used for the preparation of sodium hypophosphite, calcium phosphate and other hypophosphite.

Phosphine oxide can be used for the plating bath, pharmaceuticals, reducing agent, general reagents.
Phosphine oxide is strong reducing agent, Phosphine oxide can be used in making sodium hypophosphite, calcium phosphate and other hypophosphite.
Phosphine oxide is widely used as reducing agent, Ag, Cu, Ni, Hg and other metals are reduced to the corresponding metal, for the verification of As, Nb, Ta and other reagents, Phosphine oxide can be used for the preparation of Na, K, Ca, Mn, Fe and other types of hypophosphite.

Bleaching Agent:
Phosphine oxide is used as a bleaching or decolorizing agent for plastics, synthetic fibers, and chemicals

Color Stabilizer:
Phosphine oxide is used as a decolorizing agent and for color stabilization during the manufacture of chemicals and several plastics including: nylon fibers, polyamides, polyester fiber, polyacrilonitrile, alkyd rsins, epoxies, fatty acid esters, and glycerols.

Hypophosphite Salts:
Phosphine oxide is used in the production of Hypophosphite Salts (i.e., Calcium, Magnesium, Manganese, Potassium, Iron, and Ammonium) which are in turn used in synthetic fibers as wetting dispersing, emulsifying, and anti-static agents.

Chemical Intermediate:
Phosphine oxide is used in organic synthesis and organo Phosphine oxide production.

Neturalizing Agent:
Phosphine oxide is used as a moderately strong monobasic acid.

Catalyst:
Phosphine oxide is a polymerization and polycondensation catalyst.

Wetting Agent:
Phosphine oxide is a as a wetting, dispersing, or emulsifying agent in electroplating.

Reducing Agent:
Phosphine oxide may be used for Phosphine oxide strong but slow reducing action.

Antioxidant:
Phosphine oxide may be used as an antioxidant.

Pharmaceutical:
Phosphine oxide may be used as a stimulant in pharmaceuticals.

Uses at industrial sites:
Phosphine oxide is used in the following products: pH regulators and water treatment products, coating products, fillers, putties, plasters, modelling clay, finger paints, metal surface treatment products, non-metal-surface treatment products, laboratory chemicals, polymers, washing & cleaning products, water treatment chemicals and welding & soldering products.
Phosphine oxide has an industrial use resulting in manufacture of another substance (use of intermediates).

Phosphine oxide is used in the following areas: formulation of mixtures and/or re-packaging.
Phosphine oxide is used for the manufacture of: chemicals and plastic products.
Release to the environment of Phosphine oxide can occur from industrial use: in processing aids at industrial sites, as processing aid, as an intermediate step in further manufacturing of another substance (use of intermediates) and in the production of articles.

Preparation and Availability of Phosphine oxide:
Phosphine oxide was first prepared in 1816 by the French chemist Pierre Louis Dulong (1785–1838).

The acid is prepared industrially via a two step process:

Firstly, elemental white phosphorus reacts with alkali and alkaline earth hydroxides to give an aqueous solution of hypophosphites:
P4 + 4 OH− + 4 H2O → 4 H2PO−2 + 2 H2

Any phosphites produced in this step can be selectively precipitated out by treatment with calcium salts.

The purified material is then treated with a strong, non-oxidizing acid (often sulfuric acid) to give the free Phosphine oxide:
H2PO−2 + H+ → H3PO2

Phosphine oxide is usually supplied as a 50% aqueous solution.
Anhydrous acid cannot be obtained by simple evaporation of the water, as the acid readily oxidises to phosphorous acid and phosphoric acid and also disproportionates to phosphorous acid and phosphine.
Pure anhydrous Phosphine oxide can be formed by the continuous extraction of aqueous solutions with diethyl ether.

Preparation method of Phosphine oxide:
1. Phosphorus and barium hydroxide solution is heated, barium salt Ba (H2PO2) 2 • 2H2O can generate, sulfuric acid is added into Phosphine oxide barium solution, Ba2+ can precipitate:
Ba(H2PO2)2+H2SO4=BaSO4+2H3PO2

Phosphine oxide can be obtained by evaporating under reduced pressure and low temperature crystallization.
Due to in this process, the solubility of the barium salt is small, so the concentration of obtained Phosphine oxide is not high, industrial product should be purified by recrystallization.

2. the barium oxide (or lime) and solution of white phosphorus is heated together to form secondary barium phosphate (or calcium), and then reacts with sulfuric acid, Phosphine oxide is filtered, concentrated to obtain product, or sodium hypophosphite solution proceeds H-type ion exchange resin can derive product.
This method requires a large amount of resin, and resin regeneration and washing step is cumbersome, Phosphine oxide generally costs more than $ 7 per pound, Phosphine oxide is only suitable for small batch production, and not suitable for large-scale industrial applications.

3. Phosphine oxide is prepared by electrodialysis method, wherein the electrodialysis cell divides into three parts, they are anode chamber, raw material chamber and cathode chamber, the intermediate is separated by anionic membrane and cationic membrane, between two membranes sodium hypophosphite solution is placed (concentration of 100g/L~500g/L), anode chamber is dilute solution of Phosphine oxide 5g/L, anode chamber is dilute sodium hydroxide solution ( 5g /L), between the poles DC (3V~36V) is passed, anode releases oxygen, and generates secondary product of Phosphine oxide; cathode emits hydrogen, and generates secondary product of sodium hydroxide, the reaction time is 3~21h.

The reactions of anode chamber and cathode chamber are as follows:

Anode chamber:
H2O==H++OH-
2OH-==O2+2H2O+4e
H++H2PO2-==H3PO2

Cathode chamber:
H2O==H++OH-
2H++2e==H2
Na++OH-==NaOH

Electrodialysis method of preparation Phosphine oxide is simple and equipment investment is small, Phosphine oxide is suitable for mass production.

4. Starting from the industrial grade sodium hypophosphite, Cl-, SO42-anions which affect the quality indicators of Phosphine oxide are removed by precipitation, heavy metal ions are removed from the solution by forming sulfide, and then using strong acid cation exchange resin to obtain sodium secondary phosphate, high purity grade product can obtain.
The process can produce high-grade secondary phosphate, technically is feasible, the process is simple, easy operation, good product quality, Phosphine oxide can meet the needs of the electronics industry, defense industry and other high-tech fields.

5. Ion exchange resin method: about 70g of cation exchange resin wetted with water is packed into a glass tube with 5 mol/L hydrochloric acid circulating about 15min, after thoroughly washed with water, high purity aqueous sodium hypophosphite aqueous solution (15 g/60 ml H2O) flows through it, the resin column is first washed with 50 ml, then with 25 rnl distilled water.
The effluent acid and washing is combined, Phosphine oxide is concentrated by evaporation in water bath.
The concentrated acid is placed in high vacuum with P205 dryer for dehydration, cooling and crystallization, filtration, recrystallization, to obtain Phosphine oxide product.

Hypophosphate salts:
Many hypophosphate salts are known, for example, K4P2O6·8H2O, Ca2P2O6·2H2O, K3HP2O6·3H2O, K2H2P2O6·2H2O, KH3P2O6.

On standing in air, hypophosphates tend to oxidise to pyrophosphates containing the P2O4−7 ion where P has a formal oxidation state of +5.
Hypophosphates are stable to alkali hydroxides.
In fused sodium hydroxide they convert rapidly to the orthophosphate containing PO3−4.

Structure of Phosphine oxide:
Hypophosphorus acid contains oxonium ions and is best formulated [H3O+]2 [H2P2O6]2−.
The acid is isostructural with the diammonium salt which contains the [HOPO2PO2OH]2− anion with a P−P bond length of 219 pm.

The HOPO2PO2OH2− anion in Na2H2P2O6·6H2O has a symmetric, staggered ethane-like structure with a P−P bond of length 219 pm.
Each phosphorus atom has two P−O bonds with length 151 pm, and a P−OH bond length of 159 pm.

Chemical Structure of Phosphine oxide:
A chemical structure of a molecule includes the arrangement of atoms and the chemical bonds that hold the atoms together.
The Phosphine oxide molecule contains a total of 5 bond(s).
There are 2 non-H bond(s), 1 multiple bond(s), 1 double bond(s), and 1 hydroxyl group(s).

Formula of Phosphine oxide:
Hypophosphoric acid is a mineral acid with phosphorus in an oxidation state of +4.
Phosphine oxide has a chemical formula H4P2O6.

In the solid-state, Phosphine oxide exists as a dihydrate, H4P2O6.2H2O.
Phosphine oxide can be manufactured by reacting red phosphorus with sodium chlorite at room temperature.
In this short piece of article, let us discuss the hypophosphoric acid formula along with Phosphine oxide chemical structure, properties and uses.

Properties of Phosphine oxide:
The molecule displays P(═O)H to P–OH tautomerism similar to that of phosphorous acid; the P(═O) form is strongly favoured.

Phosphine oxide is usually supplied as a 50% aqueous solution and heating at low temperatures (up to about 90°C) prompts Phosphine oxide to react with water to form phosphorous acid and hydrogen gas.
H3PO2 + H2O → H3PO3 + H2

Heating above 110°C causes Phosphine oxide to undergo disproportionation to give phosphorous acid and phosphine.
3 H3PO2 → 2 H3PO3 + PH3

Chemical properties:
Phosphine oxide is deliquescent crystals or colorless oil.
Phosphine oxide is soluble in water, ethanol and ether, and Phosphine oxide can be mixed in any proportion with water, ethanol, acetone.
In the air, Phosphine oxide easily deliquesce to syrupy liquid, and the aqueous solution is acidic.

Phosphine oxide is monobasic acid, in aqueous solution, Phosphine oxide is strong acid, Ka = 10-2 (25℃).
Phosphine oxide is relatively stable at room temperature.

Disproportionation reaction can proceed at 130℃, decompose into phosphine and phosphorous acid:
2H3PO2=H3PO4+PH3

Phosphine oxide has strong reduction, heavy metal salt solution can be restored to metals such as Cu2 +, Hg2 +, Ag +, such as:
4Ag+H3PO2+2H2)=4Ag+H3PO4+4H+

Phosphine oxide is weak oxidizer, Phosphine oxide can be reduced to phosphine, phosphine when encounters strong reducing agent.

Reactions of Phosphine oxide:

Inorganic:
Phosphine oxide can reduce chromium(III) oxide to chromium(II) oxide:
H3PO2 + 2 Cr2O3 → 4 CrO + H3PO4

Inorganic derivatives:
Most metal-hypophosphite complexes are unstable, owing to the tendency of hypophosphites to reduce metal cations back into the bulk metal.
Some examples have been characterised, including the important nickel salt [Ni(H2O)6](H2PO2)2.

DEA List I chemical status:
Because Phosphine oxide can reduce elemental iodine to form hydroiodic acid, which is a reagent effective for reducing ephedrine or pseudoephedrine to methamphetamine, the United States Drug Enforcement Administration designated Phosphine oxide (and Phosphine oxide salts) as a List I precursor chemical effective November 16, 2001.
Accordingly, handlers of Phosphine oxide or Phosphine oxide salts in the United States are subject to stringent regulatory controls including registration, recordkeeping, reporting, and import/export requirements pursuant to the Controlled Substances Act and 21 CFR §§ 1309 and 1310.

Organic:
In organic chemistry, H3PO2 can be used for the reduction of arenediazonium salts, converting ArN+2 to Ar–H.
When diazotized in a concentrated solution of Phosphine oxide, an amine substituent can be removed from arenes.

Owing to Phosphine oxide ability to function as a mild reducing agent and oxygen scavenger Phosphine oxide is sometimes used as an additive in Fischer esterification reactions, where Phosphine oxide prevents the formation of colored impurities.

Phosphine oxide is used to prepare Phosphine oxide derivatives.

Production method of Phosphine oxide:
Ion exchange resin method: put about 70 g water-soluble cation exchange resins to fill into a glass tube.
Circulate with 5 mol/L hydrochloric acid for about 15 min and wash sufficiently with water.

Have a high aqueous sodium hypophosphite solution (15 g/60 ml H2O) to flow through the resin column, followed by being washed first with 50 ml water, and then rinsing with 25 rnl distilled water.
The effluent acid and the washings were combined and concentrated by evaporation on a water bath.
The concentrated acid is send to the highly vacuum, P205 dryer for dehydration, followed by cooling crystallization, filtration and recrystallization to obtain the finished product of Phosphine oxide.

Handling and storage of Phosphine oxide:

Precautions for safe handling:
Handling in a well ventilated place.
Wear suitable protective clothing.

Avoid contact with skin and eyes.
Avoid formation of dust and aerosols.

Use non-sparking tools.
Prevent fire caused by electrostatic discharge steam.

Conditions for safe storage, including any incompatibilities:
Store the container tightly closed in a dry, cool and well-ventilated place.
Store apart from foodstuff containers or incompatible materials.

Stability and reactivity of Phosphine oxide:

Reactivity:
Deliquescent.
Water soluble.

Possibility of hazardous reactions:
Phosphine oxide decomposes when heated into phosphoric acid and spontaneously flammable phosphine.
Phosphine oxide is oxidized by sulfuric acid with release of sulfur dioxide and sulfur.

Reacts explosively with mercury(II) oxide.
Reacts violently with mercury(II) nitrate.
Neutralizes bases in exothermic reactions.

First-aid measures of Phosphine oxide:

If inhaled:
Move the victim into fresh air.
If breathing is difficult, give oxygen.

If not breathing, give artificial respiration and consult a doctor immediately.
Do not use mouth to mouth resuscitation if the victim ingested or inhaled the chemical.

Following skin contact:
Take off contaminated clothing immediately.
Wash off with soap and plenty of water.
Consult a doctor.

Following eye contact:
Rinse with pure water for at least 15 minutes.
Consult a doctor.

Following ingestion:
Rinse mouth with water.
Do not induce vomiting.

Never give anything by mouth to an unconscious person.
Call a doctor or Poison Control Center immediately.

Most important symptoms/effects, acute and delayed:
TOXIC; inhalation, ingestion or skin contact with material may cause severe injury or death.
Contact with molten substance may cause severe burns to skin and eyes.

Avoid any skin contact.
Effects of contact or inhalation may be delayed.

Fire may produce irritating, corrosive and/or toxic gases.
Runoff from fire control or dilution water may be corrosive and/or toxic and cause pollution.

Indication of immediate medical attention and special treatment needed, if necessary:
no data available

Fire-fighting measures of Phosphine oxide:

SMALL FIRE:
Dry chemical, CO2 or water spray.

LARGE FIRE:
Dry chemical, CO2, alcohol-resistant foam or water spray.
Move containers from fire area if you can do Phosphine oxide without risk.
Dike fire-control water for later disposal; do not scatter Phosphine oxide.

FIRE INVOLVING TANKS OR CAR/TRAILER LOADS:
Fight fire from maximum distance or use unmanned hose holders or monitor nozzles.
Do not get water inside containers.

Cool containers with flooding quantities of water until well after fire is out.
Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank.
ALWAYS stay away from tanks engulfed in fire.

Specific hazards arising from the chemical:
Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes.
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.

Special protective actions for fire-fighters:
Wear self-contained breathing apparatus for firefighting if necessary.

Accidental release measures of Phosphine oxide:

Personal precautions, protective equipment and emergency procedures:
Avoid dust formation.
Avoid breathing mist, gas or vapours.

Avoid contacting with skin and eye.
Use personal protective equipment.

Wear chemical impermeable gloves.
Ensure adequate ventilation.

Remove all sources of ignition.
Evacuate personnel to safe areas.
Keep people away from and upwind of spill/leak.

Environmental precautions:
Prevent further spillage or leakage if Phosphine oxide is safe to do so.
Do not let the chemical enter drains.
Discharge into the environment must be avoided.

Methods and materials for containment and cleaning up:
Collect and arrange disposal.
Keep the chemical in suitable and closed containers for disposal.

Remove all sources of ignition.
Use spark-proof tools and explosion-proof equipment.
Adhered or collected material should be promptly disposed of, in accordance with appropriate laws and regulations.

Identifiers of Phosphine oxide:
CAS Number: 6303-21-5
ChEBI: CHEBI:29031
ChEMBL: ChEMBL2105054
ChemSpider:
10449263
10459437 (17O2)k
2342086 (2H3)
ECHA InfoCard: 100.026.001
KEGG: D02334
PubChem CID: 3085127 (2H3)
UNII: 8B1RL9B4ZJ
UN number: UN 3264
CompTox Dashboard (EPA): DTXSID90206211
InChI: InChI=1S/H3O2P/c1-3-2/h3H2,(H,1,2)
Key: ACVYVLVWPXVTIT-UHFFFAOYSA-N
InChI=1/H3O2P/c1-3-2/h3H2,(H,1,2)
Key: ACVYVLVWPXVTIT-UHFFFAOYAQ
SMILES: O[PH2]=O

CAS Numbers (All): 6303-21-5
EC Number: 228-601-5
Linear Formula: H3PO2
MDL Number: MFCD02183592
Molar Mass: 66.0 g/mol
Synonyms: Hypophosphorous acid

Synonym(s): Hypophosphorous acid
Linear Formula: H3PO2
CAS Number: 6303-21-5
Molecular Weight: 66.00
MDL number: MFCD02183592
PubChem Substance ID: 329752159
NACRES: NA.21

Properties of Phosphine oxide:
Chemical formula: H3PO2
Molar mass: 66.00 g/mol
Appearance: colorless, deliquescent crystals or oily liquid
Density: 1.493 g/cm3[2]
1.22 g/cm3 (50 wt% aq. solution)
Melting point: 26.5 °C (79.7 °F; 299.6 K)
Boiling point: 130 °C (266 °F; 403 K) decomposes
Solubility in water: miscible
Solubility: very soluble in alcohol, ether
Acidity (pKa): 1.2
Conjugate base: Phosphinate

Boiling point: 108 °C (1013 hPa) (decomposition)
Density: 1.21 g/cm3 (20 °C)
Melting Point: <-25 °C
pH value: 1 (H₂O, 20 °C)
Vapor pressure: 30 hPa (20 °C)

vapor pressure: <17 mmHg ( 20 °C)
Quality Level: 200
form: liquid

concentration:
48-52% in NaOH (titration)
50 wt. % in H2O

pH: 1 (20 °C, 500 g/L)
density: 1.206 g/mL at 25 °C
SMILES string: O[PH2]=O
InChI: 1S/H3O2P/c1-3-2/h3H2,(H,1,2)
InChI key: ACVYVLVWPXVTIT-UHFFFAOYSA-N

Boiling Point/Range: 108 °C.Decomposes on heating.
Color: Colorless
Concentration: 50.00%
Corrosivity: Corrosive to metals
Density: 1.210 - 1.260 g/cm3 (20 °C)
Flashpoint: Not applicable
Form: Liquid
Grade: Reagent Grade
Incompatible Materials: Oxidizing agents. Bases. Corrosive in contact with metals. Decomposes by reaction with alkaline solutions.
Lower Explosion Limit: Not applicable
Melting Point/Range: < -25 °C
Partition Coefficient: no data available
Purity Percentage: 50.00
Purity Details: ~50.00%
Solubility in Water: completely miscible
Upper Explosion Limit: Not applicable
Vapor Pressure: 30 hPa (20 °C)
Viscosity: no data available
pH-Value: 1.0 (20 °C)
Product Line: Puriss. p.a.
Storage Temperature: Ambient

Molecular Weight: 65.996 g/mol
XLogP3-AA: -1.1
Hydrogen Bond Donor Count: 1
Hydrogen Bond Acceptor Count: 2
Rotatable Bond Count: 0
Exact Mass: 65.98706633 g/mol
Monoisotopic Mass: 65.98706633 g/mol
Topological Polar Surface Area: 37.3Å²
Heavy Atom Count: 3
Complexity: 10.3
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: 1
Compound Is Canonicalized: Yes

Specifications of Phosphine oxide:
Property: Value
Assay: 48.5 - 51.4 %
Density (D 20/4): 1.208 - 1.220
Arsenic (As): Max. 0.5 ppm
Barium (Ba): Max. 50 ppm
Calcium (Ca): Max. 50 ppm
Cadmium (Cd): Max. 1 ppm
Cobalt (Co): Max. 1 ppm
Chromium (Cr): Max. 1 ppm
Copper (Cu): Max. 1 ppm
Iron (Fe): Max. 10 ppm
Potassium (K): Max. 10 ppm
Magnesium (Mg): Max. 10 ppm
Manganese (Mn): Max. 1 ppm
Sodium (Na): Max. 2000 ppm
Nickel (Ni): Max. 1 ppm
Lead (Pb): Max. 1 ppm
Zinc (Zn): Max. 1 ppm
Chloride (Cl): Max. 200 ppm
Total S (as SO4): Max. 200 ppm
Phosphate, phosphite (as H3PO4): Max. 1 %

Assay (alkalimetric): ≥ 49.5 %
Phosphorous acid and phosphoric acid (as H₃PO₃): ≤ 2
Chloride (Cl): ≤ 0.015 %
Total sulfur (as SO₄): ≤ 0.02 %
As (Arsenic): ≤ 0.0005 %
Ba (Barium): ≤ 0.005 %
Ca (Calcium): ≤ 0.005 %
Cd (Cadmium): ≤ 0.0001 %
Cu (Copper): ≤ 0.0005 %
Fe (Iron): ≤ 0.005 %
K (Potassium): ≤ 0.001 %
Mn (Manganese): ≤ 0.0005 %
Na (Sodium): ≤ 0.10 %
Ni (Nickel): ≤ 0.0005 %
Pb (Lead): ≤ 0.0005 %
Zn (Zinc): ≤ 0.0001 %

Structure of Phosphine oxide:
Molecular shape: pseudo-tetrahedral

Related compounds of Phosphine oxide:
Sodium hypophosphite
Barium hypophosphite

Related phosphorus oxoacids:
Phosphorous acid
Phosphoric acid

Names of Phosphine oxide:

Regulatory process names:
Hypophosphorous acid
hypophosphorous acid
Hypophosphorous acid (VAN)
Hypophosphorus acid
Phosphine oxide, hydroxy-
Phosphinic acid
Phosphinic acid
phosphinic acid
Phosphonous acid (VAN)

IUPAC names:
hydroxy-oxophosphanium
HYPOPHOSPHOROUS ACID
Hypophosphorous acid
hypophosphorous acid
Hypophosphorous acid
Hypophosphorus Acid
phosphenous acid
Phosphinic acid
phosphinic acid
Phospinic Acid
Unterphosphorige Säure
Phosphinic acid

Trade names:
Hypophosphorous acid
Hypophosphorous acid 50 %

Other names:
Hydroxy(oxo)-λ5-phosphane
Hydroxy-λ5-phosphanone
Oxo-λ5-phosphanol
Oxo-λ5-phosphinous acid
Phosphonous acid (for minor tautomer)

Other identifiers:
60062-19-3
6303-21-5