Phosphonsure

Bezeichnung:Phosphonsure

CAS-Nr13598-36-2

Englisch Name:Phosphorous acid

CBNumberCB6700409

SummenformelH3O3P

Molgewicht82

MOL-Datei13598-36-2.mol

Synonyma

Phosphonsure

Phosphonsure physikalisch-chemischer Eigenschaften

Schmelzpunkt	73 °C
Siedepunkt	200 °C
Dichte	1.651 g/mL at 25 °C(lit.)
Dampfdruck	0.001Pa at 20℃
Flammpunkt	200°C
storage temp.	0-6°C
Löslichkeit	DMSO (Slightly), Methanol (Slightly), Water (Sparingly)
Aggregatzustand	Crystals
pka	pK1 1.29; pK2 6.74(at 25℃)
Wichte	1.651
Farbe	White
Wasserlöslichkeit	SOLUBLE
Sensitive	Air Sensitive & Hygroscopic
Merck	14,7346
Stabilität	Stable. Incompatible with strong bases. Hygroscopic.
CAS Datenbank	13598-36-2(CAS DataBase Reference)
NIST chemische Informationen	(HO)2HPO(13598-36-2)
EPA chemische Informationen	Phosphonic acid (13598-36-2)

Sicherheit

Kennzeichnung gefährlicher	C
R-Sätze:	22-35
S-Sätze:	26-36/37/39-45
RIDADR	UN 2834 8/PG 3
WGK Germany	1
RTECS-Nr.	SZ6400000
F	3
TSCA	Yes
HazardClass	8
PackingGroup	III
HS Code	28092019

Gefahreninformationscode (GHS)

Phosphorous acid Chemische Eigenschaften,Einsatz,Produktion Methoden

R-Sätze Betriebsanweisung:
R22:Gesundheitsschädlich beim Verschlucken.
R35:Verursacht schwere Verätzungen.
S-Sätze Betriebsanweisung:
S26:Bei Berührung mit den Augen sofort gründlich mit Wasser abspülen und Arzt konsultieren.
S36/37/39:Bei der Arbeit geeignete Schutzkleidung,Schutzhandschuhe und Schutzbrille/Gesichtsschutz tragen.
S45:Bei Unfall oder Unwohlsein sofort Arzt zuziehen (wenn möglich, dieses Etikett vorzeigen).
Beschreibung
Phosphorous acid, H3PO3, is diprotic (readily ionizes two protons), not triprotic as might be suggested by this formula. Phosphorous acid is as an intermediate in the preparation of other phosphorous compounds. Because preparation and uses of “phosphorous acid” actually pertain more to the major tautomer, phosphonic acid, it is more often referred to as “phosphorous acid”. Phosphorous acid has the chemical formula H3PO3, which is best expressed as HPO(OH)2 to show its diprotic character. P(OH)3 (IUPAC: phosphorous acid) has CAS number 10294-56-1. It has been shown to be a stable tautomer.
Chemische Eigenschaften
Phosphorous acid is a white crystalline deliquescent solid that can be prepared by the action of water on phosphorus( III) oxide or phosphorus(III) chloride. It is a dibasic acid producing the anions H2PO3- and HPO3 2- in water. The acid and its salts are slow reducing agents. On warming, phosphonic acid decomposes to phosphine and phosphoric(V) acid. Phosphorus acid is used to prepare phosphite salts. It is usually sold as a 20% aqueous solution.
Physikalische Eigenschaften
White crystalline mass; deliquescent; garlic-like odor; density 1.651 g/cm³ at 21°C; melts at 73.6°C; decomposes at 200°C to phosphine and phosphoric acid; soluble in water, about 310 g/100mL; K₁ 5.1x10^-2 and K₂ 1.8x10^-7; soluble in alcohol.
Verwenden
Phosphorous acid is used to produce the fertilizer phosphate salt like potassium phosphite, ammonium phosphite and calcium phosphite. It is actively involved in the preparation of phosphites like aminotris(methylenephosphonic acid) (ATMP), 1-hydroxyethane 1,1-diphosphonic acid (HEDP) and 2-phosphonobutane-1,2,4-tricarboxylic Acid (PBTC), which find application in water treatment as a scale or corrosive inhibitor. It is also used in chemical reactions as a reducing agent. Its salt, lead phosphite is used as PVC stabilizer. It is also used as a precursor in the preparation of phosphine and as an intermediate in the preparation of other phosphorus compounds.
Definition
ChEBI: Phosphorous acid is a phosphorus oxoacid. It is a conjugate acid of a dihydrogenphosphite. It is a tautomer of a phosphonic acid.
Application
Phosphorous acid (H3PO3, orthophosphorous acid) may be used as one of the reaction components for the synthesis of the following:
α-aminomethylphosphonic acids via Mannich-Type Multicomponent Reaction
1-aminoalkanephosphonic acids via amidoalkylation followed by hydrolysis
N-protected α-aminophosphonic acids (phospho-isosteres of natural amino acids) via amidoalkylation reaction
synthetische
Phosphorus acid can be prepared by the reaction of phosphorus trichloride with water:
PCl₃ + 3H₂O → H₃PO₄ + 3HCl
The reaction is violent. Addition of PCl₃ should be extremely cautious and slow. The addition can be carried out safely in the presence of concentrated HCl. Alternatively, a stream of air containing PCl₃ vapor is passed into icecold water and solid crystals of H₃PO₄ form.
Alternatively, phosphorus acid can be prepared by adding phosphorus trichloride to anhydrous oxalic acid:
PCl₃ + 3(COOH）₂ → H₃PO₃ + 3CO + 3CO₂ + 3HCl
In this reaction, all products except H₃PO₃ escape as gases leaving the liquid acid.
Dissolution of phosphorus sesquioxide in water also forms phosphorus acid. When shaken with ice water, phosphorus acid is the only product .
P₄O₆ + 6H₂O → 4H₃PO₃
However, in hot water part of the phosphorus acid disproportionates to phosphoric acid and phosphorus or phosphine.
Allgemeine Beschreibung
Phosphorous acid appears as a white or yellow crystalline solid (melting point 70.1 deg C) or a solution of the solid. Density 1.651 g /cm3 . Contact may severely irritate skin, eyes, and mucous membranes. Toxic by ingestion, inhalation and skin absorption.
Air & Water Reaktionen
Deliquescent. Absorbs oxygen from the air very readily to form phosphoric acid [Hawley]. Soluble in water.
Reaktivität anzeigen
Phosphorous acid decomposes when heated to form phosphine, a gas that usually ignites spontaneously in air. Absorbs oxygen from the air to form phosphoric acid [Hawley]. Forms yellow deposits in aqueous solution that are spontaneously flammable upon drying. Reacts exothermically with chemical bases (for example: amines and inorganic hydroxides) to form salts. These reactions can generate dangerously large amounts of heat in small spaces. Dissolution in water or dilution of a concentrated solution with additional water may generate significant heat. Reacts in the presence of moisture with active metals, including such structural metals as aluminum and iron, to release hydrogen, a flammable gas. Can initiate the polymerization of certain alkenes. Reacts with cyanide compounds to release gaseous hydrogen cyanide. May generate flammable and/or toxic gases in contact with dithiocarbamates, isocyanates, mercaptans, nitrides, nitriles, sulfides, and strong reducing agents. Additional gas-generating reactions occur with sulfites, nitrites, thiosulfates (to give H2S and SO3), dithionites (to give SO2), and carbonates (to give CO2).
Health Hazard
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.
Brandgefahr
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.
Flammability and Explosibility
Non flammable
Industrielle Verwendung
This collector was developed recently and was used primarily as specific collector for cassiterite from ores with complex gangue composition.On the basis of the phosphonic acid, Albright and Wilson had developed a range of collectors mainly for flotation of oxidic minerals (i.e. cassiterite, ilmenite and pyrochlore). Very little is known about the performance of these collectors. Limited studies conducted with cassiterite and rutile ores showed that some of these collectors produce voluminous froth but were very selective.
Sicherheitsprofil
Moderately toxic by ingestion. When heated to decomposition at 200℃ it emits toxic fumes of POx and phosphme whch may ignite. See also PHOSPHINE.

Phosphorous acid Upstream-Materialien And Downstream Produkte

Phosphonsure Anbieter Lieferant Produzent Hersteller Vertrieb Händler.

13598-36-2, Phosphorous acid Verwandte Suche:

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