Sodium formate

Structural formula
General
Surname	Sodium formate
other names	Sodium methanoate
Molecular formula	CHNaO 2
Brief description	colorless, deliquescent, bitter-salty tasting, rhombic prisms or bars
External identifiers / databases
CAS number 141-53-7 EC number 205-488-0 ECHA InfoCard 100.004.990 PubChem 2723810 Wikidata Q409209
properties
Molar mass	68.01 g mol −1
Physical state	firmly
density	1.92 g cm −3 (20 ° C)
Melting point	261 ° C (decomposition)
solubility	> 490 g l −1 (20 ° C) in water
safety instructions
GHS labeling of hazardous substances no GHS pictograms H and P phrases H: no H-phrases P: no P-phrases
Thermodynamic properties
ΔH f 0	−666.5 kJ / mol
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Sodium formate is the sodium salt of formic acid with the constitutional formula Na (HCOO).

presentation

Technically, sodium formate is produced from caustic soda and carbon monoxide at 130 ° C and 6–8 bar pressure:

${\displaystyle \mathrm {NaOH+CO\longrightarrow HCOONa} }$

Sodium hydroxide reacts with carbon monoxide to form sodium formate.

Because of the inexpensive large-scale availability of formic acid by carbonylation of methanol and hydrolysis of the resulting methyl formate , sodium formate is usually produced by neutralizing formic acid with sodium hydroxide solution . Sodium formate is also produced as an inevitable product in the last stage of pentaerythritol synthesis, the cross Cannizzaro reaction of formaldehyde with the aldol reaction product trimethylolacetaldehyde [3-hydroxy-2,2-bis (hydroxymethyl) propanal].

properties

Physical Properties

Sodium formate crystallizes in the monoclinic crystal system in the space group C 2 / n (space group no.15, position 5) with the lattice parameters a = 6.19  Å , b = 6.72 Å, c = 6.49 Å and β = 121, 7 °.

Chemical properties

When heated, sodium formate first decomposes to form sodium oxalate and hydrogen . The resulting sodium oxalate changes into sodium carbonate on further heating, releasing carbon monoxide .

${\displaystyle \mathrm {2\ HCOONa\ {\xrightarrow {\ \Delta \ }}\ \ (COO)_{2}Na_{2}+H_{2}\uparrow } }$

${\displaystyle \mathrm {(COO)_{2}Na_{2}\ {\xrightarrow {>290^{o}}}\ \ Na_{2}CO_{3}+CO\uparrow } }$

As a salt of a weak acid (formic acid) and a strong base ( caustic soda ), a solution of sodium formate in water has a basic reaction:

${\displaystyle \mathrm {HCOO^{-}+H_{2}O\ \leftrightharpoons HCOOH+OH^{-}} }$

A solution of formic acid and sodium formate can therefore be used as a buffer solution .

use

Sodium formate plays a role in the synthesis of formic acid , here it is converted to sulfuric acid under the following reaction equation:

${\displaystyle \mathrm {2\ HCOONa+H_{2}SO_{4}\longrightarrow 2\ HCOOH+Na_{2}SO_{4}} }$

The sodium formate is reacted with sulfuric acid to form formic acid and sodium sulfate

In addition to formic acid, the stinging hairs of nettles also contain sodium formate.

Sodium formate is slightly hazardous to water and inhibits some types of bacteria , but it is broken down by others.

Solid sodium formate is used at airports to de-icing runways, taxiways and aprons, mixed with anti-corrosive agents and other additives, as a non-corrosive grit that quickly penetrates solid layers of snow and ice, detaches them from the asphalt or concrete and the ice quickly melts ("De-icing effect"). The high freezing point depression z. For example, in comparison to the thawing agent urea , which is still frequently used but problematic because of its eutrophication effect , effectively prevents re-icing ("anti-icing effect"), even at very low temperatures below −15 ° C. The thawing effect of the solid sodium formate can be increased by moistening it with aqueous potassium formate or potassium acetate solutions. The degradability of the sodium formate is connected to a chemical oxygen demand COD of 211 mg O ₂ / g compared with the de-icing sodium acetate with 740 mg O ₂ / g and urea with> 2,000 mg O ₂ / g is particularly advantageous.

Saturated sodium formate solutions as well as mixtures of other alkali metal formates, e.g. B. potassium and cesium formate, used because of their relatively high density as an important drilling and stabilization aid in gas and oil exploration. Any desired densities between 1.0 and 2.3 g / cm ^{3 can be} set by mixing the corresponding saturated alkali metal formate solutions . The saturated solutions are biocidal and have long-term stability against microbial degradation. Once diluted, they are quickly and completely biodegradable. Since in alkali metal formates as drilling aids on the addition of solid fillers, such as. B. barite to increase the density can be dispensed with and formate solutions can be recovered and recycled at the drilling site, formates represent an important advance in exploration technology.

Sodium formate is also used to make oxalic acid .

Individual evidence

1. ↑ Entry on sodium formate. In: Römpp Online . Georg Thieme Verlag, accessed on June 19, 2014.
2. ↑ ^{a b c d e} Entry on sodium formate in the GESTIS substance database of the IFA , accessed on December 19, 2019 (JavaScript required)
3. ↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Standard Thermodynamic Properties of Chemical Substances, pp. 5-19.
4. ^ Arnold Willmes, Pocket Book Chemical Substances , Harri Deutsch, Frankfurt (M.), 2007.
5. ↑ H.-J. Arpe, Industrial Organic Chemistry , 6th, completely revised. Ed., Wiley-VCH Verlag, 2007, ISBN 978-3-527-31540-6
6. ^ WH Zachariasen: "The Crystal Structure of Sodium Formats, NaHCO ₂ " in J. Am. Chem. Soc. , 1940 , 62 (5), pp. 1011-1013. doi : 10.1021 / ja01862a007
7. ^ ^{A b} T. Meisel, Z. Halmos, K. Seybold, E. Pungor: "The thermal decomposition of alkali metal formats" in Journal of Thermal Analysis and Calorimetry 1975 , 7 (1). Pp. 73-80. doi : 10.1007 / BF01911627
8. ↑ T. Yoshimori, Y. Asano, Y. Toriumi, T. Shiota: "Investigation on the drying and decomposition of sodium oxalate" in Talanta 1978 , 25 (10) pp. 603-605. doi : 10.1016 / 0039-9140 (78) 80158-1
9. ↑ Deicer anti-icing Snow melting Thawing Chemicals Manufacturers
10. ^ William Benton and Jim Turner, Cabot Specialty Fluids: Cesium formats fluid succeeds in North Sea HPHT field trials (PDF; 88 kB); In: Drilling Contractor, May / June 2000.