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Salts & Minerals

Potassium sodium tartrate tetrahydrate

CAS: 6381-59-5

Overview

Potassium sodium tartrate tetrahydrate (CAS 6381-59-5 ), also known as Rochelle salt and approved as E337 , is a double salt of tartaric acid used across food, pharmaceutical, and cosmetic manufacturing.

It functions primarily as a buffering agent, chelating agent, and stabilizer in formulated products. In food processing, E337 buffers pH in confectionery, dairy, and baked goods while sequestering metal ions.

These metal ions would otherwise accelerate oxidative spoilage. Pharmaceutical manufacturers use it as an excipient in effervescent formulations and laxative preparations, where its buffering capacity supports product stability.

In personal care, it chelates trace metals in creams and lotions, protecting active ingredients from degradation during shelf life. It also serves as a complexing agent in electroplating baths and analytical reagent applications.

Consistent purity is critical for these industrial uses. Potassium sodium tartrate tetrahydrate is supplied as a white crystalline powder or granules. Food-grade material is available to FCC specification.

Pharmaceutical supply meets USP and BP / Ph. Eur. standards. Technical grade is also available for industrial and laboratory use, ensuring versatility across various manufacturing sectors.

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Physical Properties

Melting Point70-80 °C
Boiling Point220°C
Density1.77 g/cm³
Appearancewhite semi-transparent crystals
ColorWhite semi-transparent
OdorOdorless
FormSolid
Water Solubility630 g/L (20 ºC)
Refractive Index22 ° (C=10, H2O)
pH7.0-8.5 (25℃, 50mg/mL in H2O)
Log P-1.426 (est)

Trade & Regulatory

HS Code29181300
Storage Class11 - Combustible Solids
WGK (Germany)3

Other Names

Rochelle potassium sodium tartrate | PotassiuM SodiuM L-(+)-Tartrate Tetrahydrate | rel-Potassium sodium (2R3R)-23-dihydroxysuccinate tetrahydrate | Monopotassium monosodium tartrate tetrahydrate | Potassium sodium tartrate [USP] | potassiumsodium(2R3R)-23-dihydroxybutanedioatetetrahydrate | Tartaric acidmonopotassium monosodium salttetrahydrateL-(+)- | Sodium potassium tartrate | E337

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Chemical Properties

CAS Number
6381-59-5
EC Number
613-385-0
Mol. Weight
282.22
HS Code
29181300

Industries

Documentation