Phosphorus pentoxide brief introduction

Phosphorus pentoxide(Chemical formula: P2O5, molecular formula: P4O10), phosphorus oxide generated by the combustion of phosphorus in air. It has strong water absorption and extremely strong dehydration ability, and can even dehydrate concentrated sulfuric acid to produce sulfur trioxide. Highly deliquescent, it is a powerful desiccant. It generates phosphoric acid with cold water and mainly forms orthophosphate with hot water.

Phosphorus pentoxide Basic information

Phosphorus pentoxide Numbering system

Phosphorus pentoxide Physical and Chemical Properties

Appearance and characteristics:

White to yellow crystalline powder

Density:

2.3 g/mL at 25 °C(lit.)

Boiling point:

122 °C (1 mmHg)

Melting point:

340 °C(lit.)

Flash point:

340-360°C

Refractive index:

1.433-1.436

Stability:

Stability Stable, but reacts violently with water, alcohols, metals, sodium, potassium, ammonia, oxidizing agents, HF, peroxides, magnesium, strong bases.

Storage conditions:

The warehouse is ventilated, low-temperature and dry, and stored separately from alkaline and flammable materials

Steam density:

4.9 (vs air)

Steam pressure:

1 mm Hg ( 384 °C)

security information

• RTECS：

• TH3945000

Safety instructions:

S22-S26-S45

Hazard category code:

R35

WGK Germany：

one

Dangerous goods transportation code:

UN 1807 8/PG 2

Customs code:

two billion eight hundred and nine million and one hundred thousand

Hazard category:

eight

Packaging grade:

II

Dangerous goods signs:

C

Hazard description:

H314

Hazard prevention instructions:

P260; P280; P303 + P361 + P353; P304 + P340 + P310; P305 + P351 + P338

Signal words:

Danger

Supplementary Hazard Statement:

Reacts violently with water.

Danger signs:

GHS05

Production method and purpose

Production method

1. The oxidation method heats and melts yellow phosphorus, which is then sent to an oxidation combustion furnace. Dry air (dehydrated with concentrated sulfuric acid) is used for oxidation combustion reaction, generating pentoxide. Phosphorus pentoxide sublimates due to heating and falls into the settling chamber at the bottom of the oxidation combustion furnace when cooled at the top of the furnace, producing finished pentoxide. The tail gas emitted from the oxidation combustion furnace is separated by a cyclone separator to recover phosphorus pentoxide dust. The recycled products are packaged together with the products in the settling chamber as finished products. Its 4P+5O2 → 2P2O5 uses reagent grade phosphorus pentoxide as raw material, and is purified by burning and sublimating in a fully dry oxygen flow. The sublimate is captured by a condenser to produce high-purity phosphorus pentoxide products.

2. Install a wide mouthed funnel made of tinplate on the wide mouthed bottle, with a tinplate cylinder (diameter 350mm, height 500mm) lined with tin that is smaller than the funnel mouth. The bottom of the cylinder is equipped with a ventilation elbow, and there is a hole in the middle and upper parts for installing a combustion spoon. Heat the burning spoon, add dry white phosphorus to the spoon, quickly insert it into the cylinder, and fix it on the cylinder with the stopper on the handle of the burning spoon. Repeat this operation after the phosphorus is burned out. The ventilation intensity and combustion speed can be controlled by adjusting the gap size between the cylinder and the funnel. The phosphorus oxide generated by combustion is cooled on the inner wall of the cylinder. Gently tap the cylinder and it will fall into the wide mouthed bottle. The purified phosphorus oxide produced in the market or as mentioned above often contains low valent oxides of phosphorus, sometimes also yellow phosphorus. It can be directly used in general experiments, but if a purer one is needed, it can be further calcined and sublimated in a dry oxygen stream. Invert a dry and clean T-shaped tube, and install a P2O5 glass tube with starting materials on the tube mouth. Introduce oxygen dried with CaCl2 from one end of the T-shaped tube, and connect the other end to a glass cooling tube. Heat the P2O5 to be burned and sublimated in a T-shaped tube. 200g of commercially available sample can yield approximately 70g of pure product after 2 hours. Using reagent grade phosphorus pentoxide as the raw material, high-purity phosphorus pentoxide products are obtained by burning, sublimating, and purifying in a fully dry oxygen gas stream. The sublimates are captured by a condenser.

3. Under the action of pure oxygen gas stream pre dried with concentrated sulfuric acid, solid potassium hydroxide, and industrial phosphorus pentoxide, industrial phosphorus pentoxide can be sublimated and purified to obtain phosphorus pentoxide without lower oxides.

use to

Phosphorus pentoxide is a common raw material and reagent in the chemical industry. This product is widely used in industries such as medicine, coating additives, printing and dyeing additives, anti-static agents, titanium ester coupling agents, phosphorus oxychloride, chemical industry, etc. It is mainly used to manufacture high-purity phosphoric acid and is used as a gas and liquid desiccant.