Sodium formate is a chemical compound that serves as the sodium salt of formic acid. It appears as a white, crystalline solid, often in powder or granular form. This organic sodium salt contains a formate ion combined with a sodium ion.
Chemical Identity and Properties
Sodium formate (HCOONa) is the sodium salt of formic acid (HCOOH). It presents as a white, crystalline powder and can be deliquescent, absorbing moisture from the air. Its density is approximately 1.92 grams per cubic centimeter at 20°C.
The compound is highly soluble in water, with solubility increasing significantly with temperature; for instance, at 20°C, about 97.2 grams can dissolve in 100 mL of water. It is also soluble in glycerol and alcohol but insoluble in ether. Sodium formate has a high melting point of 253°C and decomposes upon further heating, initially forming sodium oxalate and hydrogen.
Diverse Applications
Sodium formate finds extensive use across various industries due to its unique chemical properties.
De-icing Agent
It is a prominent de-icing agent, particularly on airport runways and roads. It serves as a less corrosive alternative to traditional chloride-based salts, and its high freezing point depression helps prevent ice formation even at temperatures below -15°C. This makes it a more environmentally sound choice for sensitive ecosystems near transportation infrastructure.
Leather Industry
In the leather industry, sodium formate is employed in the tanning process. It aids in stabilizing chromium, contributing to better leather quality and improving the penetration of tanning agents, which helps soften and preserve the leather.
Textile Industry
The textile industry utilizes sodium formate in dyeing and printing processes. It functions as a reducing agent or pH buffer, enhancing dye uptake and fixation, resulting in more vibrant colors and improved fabric quality.
Oil and Gas Industry
Sodium formate is also widely used in the oil and gas industry, specifically in drilling fluids. Saturated solutions of alkali metal formates, including sodium formate, achieve high densities in drilling and stabilizing aids. These solutions are biocidal, stable against microbial degradation, and can be recovered and recycled at drilling sites, reducing the need for solid fillers and improving exploration technology.
Other Applications
Other applications include its use as an animal feed additive (E237) to preserve feed. It also serves as a cryoprotectant in structural biology for X-ray diffraction experiments on protein crystals, protecting biological samples at very low temperatures. Additionally, it is used in the production of formic acid.
Safety and Environmental Considerations
Sodium formate has low toxicity but can cause irritation upon contact. It may be harmful if swallowed or inhaled, and direct contact with skin or eyes can cause irritation. Basic handling precautions include wearing gloves, eye protection, and ensuring good ventilation to avoid dust inhalation.
Sodium formate is biodegradable. This is advantageous in de-icing applications, where it poses a lower environmental impact than traditional de-icers like sodium chloride and urea. Its degradation rate varies with temperature. While low in acute toxicity to aquatic organisms, prolonged exposure to high concentrations can have adverse effects. Industries must manage its use responsibly to prevent issues like soil contamination from runoff.