What Is Sodium Formate?
Sodium formate is the sodium salt of formic acid, with the molecular formula HCOONa and a molecular weight of 68.01. Its Chemical Abstracts Service number is 141-53-7. The compound is produced by the reaction of formic acid with sodium hydroxide or sodium carbonate, and it also arises as a by-product in certain industrial processes such as pentaerythritol production. Pure sodium formate occurs as a white crystalline powder or granules and is hygroscopic, meaning it tends to absorb moisture from the air.
Physical and Chemical Properties
Sodium formate combines the properties of a salt, a mild reducing agent and a buffer. The table below summarizes its main characteristics.
| Property | Value |
|---|---|
| Chemical name | Sodium formate |
| CAS number | 141-53-7 |
| Molecular formula | HCOONa |
| Molecular weight | 68.01 |
| Appearance | White crystalline powder or granules |
| Solubility | Readily soluble in water; slightly soluble in ethanol; practically insoluble in ether |
| pH behavior | Acts as a buffering salt around the pKa of formic acid, approximately 3.75 |
Because the formate ion can donate hydrogen, sodium formate behaves as a mild reducing agent and can decompose to release formic acid when acidified. These properties are the basis of most of its applications.
What Does Food Grade Sodium Formate Mean?
The food grade designation refers to a purity standard rather than a role as a direct food additive. Food grade sodium formate is manufactured with tightly controlled impurity levels, particularly for heavy metals and other contaminants, so that it can be used in food processing environments, feed applications and other sensitive uses where technical grade material would not be acceptable. Buyers should verify the certificate of analysis against the applicable specification, as requirements differ by region and end use.
Main Applications of Sodium Formate
Sodium formate serves multiple functions across different industries:
Buffering agent: in leather tanning and textile dyeing, it stabilizes pH and supports chrome tanning baths.
De-icing agent: it is used in runway and road de-icing formulations, offering lower corrosion than chloride-based salts.
Reducing agent: in chemical synthesis, formate salts are used in reduction reactions and in catalytic transfer hydrogenation.
Pharmaceuticals: it is an intermediate or auxiliary material in the production of formate derivatives and other active ingredients.
Rubber industry: it serves as a coagulant and process auxiliary in rubber manufacturing.
Agriculture and feed: high-purity sodium formate is used as a silage additive and in certain feed applications subject to local regulations.
Oilfield and drilling: it is used in drilling fluid formulations as a density and buffering additive.
This wide application range makes sodium formate a versatile commodity chemical with steady industrial demand.
Quality Criteria and Handling
When purchasing sodium formate, the following quality and handling points should be considered:
Assay: food grade material typically has a sodium formate content of 99% or higher.
Impurities: verify limits for heavy metals, chloride, sulfate and moisture against the applicable specification.
Packaging: sodium formate is usually supplied in multi-layer paper or woven bags with a polyethylene liner to protect against moisture.
Storage: keep in a dry, ventilated warehouse; protect from moisture and from contact with strong acids, which release formic acid.
Handling: wear dust protection, gloves and eye protection; avoid inhaling dust and wash after handling.
Correct specification and storage ensure that the material performs reliably in its intended application.
Frequently Asked Questions
Is sodium formate the same as sodium benzoate?
No. Sodium formate is the sodium salt of formic acid, while sodium benzoate is the sodium salt of benzoic acid. They have different chemical structures, properties and applications.
What is food grade sodium formate used for?
Food grade sodium formate is used as a buffering agent, de-icing agent and reducing agent in applications with stricter purity requirements, including food processing environments, feed and silage applications, subject to the regulations of the relevant market.
Is sodium formate safe?
Sodium formate has low acute toxicity, but it can irritate the eyes, skin and respiratory tract, and it releases formic acid when mixed with strong acids. Food grade material meets defined impurity limits, but industrial handling still requires dust protection and good hygiene.
What is the CAS number of sodium formate?
The CAS number of sodium formate is 141-53-7.
How is sodium formate produced?
Sodium formate is produced by neutralizing formic acid with sodium hydroxide or sodium carbonate. It is also recovered as a by-product in the manufacture of pentaerythritol and other chemicals.
Does sodium formate dissolve in water?
Yes. Sodium formate is readily soluble in water, which is why it is convenient to dose as an aqueous solution in most industrial applications.
