Мононатрийфосфат

Description

Monosodium phosphate (monobasic sodium phosphate, sodium dihydrogen phosphate) is the acidic sodium salt of orthophosphoric acid, formula H3O4P.Na (NaH2PO4), CAS 7558-80-7. It is found in anhydrous form and as mono- and dihydrate.

Synonyms

Monosodium phosphate, Sodium dihydrogen phosphate, Monobasic sodium phosphate, Sodium primary phosphate, Sodium dihydrogen orthophosphate.

Basic Attributes

• Molecular weight: 119.97700
• Exact weight: 119.95900
• EU number: 618-243-1
• UNII: KH7I04HPUU
• DSSTox ID: DTXSID7035222
• HS code: 2835220000
• PSA: 90.40000
• XLogP3: -0.49040

Physico-chemical characteristics

• Color/form: colorless monoclinic crystals or white crystalline powder
• Appearance: white, slightly diffuse crystals or odorless granules

Scope of application

Monosodium phosphate is an acidic component of phosphate buffer systems, widely used in the food industry as an acidity regulator, leavening agent and stabilizer (in combination with dibasic and tribasic sodium phosphates to fine-tune the pH), in pharmaceuticals - as a component of saline laxatives that help increase the volume of fluid in the small intestine and stimulate bowel movements, usually within 30 minutes - 6 hours after administration. It is also used in laboratory practice for the preparation of phosphate buffer solutions and in water treatment.

Mechanism of action

In pharmacological use, sodium phosphate acts as an osmotic laxative: phosphate ions retain water in the intestinal lumen, increasing the volume of its contents and mechanically stimulating peristalsis. In buffer systems, the dihydrogen phosphate ion (H2PO4-) forms a conjugate acid-base pair with hydrogen phosphate (HPO4²-), stabilizing the pH of the solution in the range of about 6.2-7.2 (the buffer capacity region of the phosphate system).

Forms of existence

According to USP 32 nomenclature, monobasic sodium phosphate may contain one or two molecules of water of hydration or be anhydrous. Hydrated forms are odorless, colorless or white crystals, slightly blurry; anhydrous form - white crystalline powder or granules.

Storage and transportation

Store in a dry, well-closed container at room temperature - the substance is hygroscopic and slightly diffuses in air. There is no special transport hazard classification given in the dump.

Additional Applications

Monosodium phosphate is a component of classical phosphate buffer systems (for example, Sorensen buffer) in biochemical and microbiological laboratories, a source of phosphorus and a pH regulator in nutrient media for yeast and microorganisms during fermentation, as well as an active component of effervescent tablets and flame retardant impregnations for wood and textiles, where phosphate slows down combustion due to the formation of a non-flammable protective crust during thermal decomposition.