Ammonium acetate

Structural formula
General
Surname	Ammonium acetate
Molecular formula	C 2 H 7 NO 2
External identifiers / databases
CAS number 631-61-8 EC number 211-162-9 ECHA InfoCard 100.010.149 PubChem 12432 Wikidata Q410156
properties
Molar mass	77.08 g mol −1
Physical state	firmly
density	1.17 g cm −3
Melting point	114 ° C
boiling point	Decomposition from 90 ° C
solubility	very good in water (1480 g l −1 at 20 ° C) good in ethanol
safety instructions
GHS labeling of hazardous substances no GHS pictograms H and P phrases H: no H-phrases P: no P-phrases
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Ammonium acetate , CH ₃ COONH ₄ , is the ammonium salt of acetic acid . It forms colorless crystals with a faint smell of acetic acid , which dissolve very well in water and well in ethanol . In the solid state it forms a hygroscopic mass which reacts neutrally in solution.

synthesis

Ammonium acetate can be obtained by reacting ammonium carbonate or ammonia with glacial acetic acid .

${\displaystyle \mathrm {2\ CH_{3}COOH+(NH_{4})_{2}CO_{3}\longrightarrow 2\ NH_{4}(CH_{3}COO)+\ H_{2}O+\ CO_{2}\uparrow } }$

${\displaystyle \mathrm {CH_{3}COOH+NH_{3}\longrightarrow NH_{4}(CH_{3}COO)} }$

use

Ammonium acetate is used in dyeing, meat preservation and in biochemical laboratory work. In the laboratory it is used to make buffer solutions to stabilize the pH . The dissociation constants of ammonia and acetic acid in water are almost identical; Solutions of ammonium acetate therefore have a pH of 7.0, relatively regardless of the concentration. In microscopy , it is used in a mixture with gum arabic as an inclusion agent for the production of permanent preparations.

In genetic engineering , the DNA is sometimes precipitated with the help of ammonium acetate. In contrast to sodium acetate , no oligonucleotides and no free dNTPs are precipitated, so that DNA precipitated in this way is more suitable for the transfection of mammalian cells. However, it is not suitable if kinases are to be used later .

Reactions

When heated, ammonium acetate breaks down to acetamide, splitting off water .

${\displaystyle \mathrm {CH_{3}COONH_{4}\ {\xrightarrow[{}]{\Delta T}}\ CH_{3}{-}CO{-}NH_{2}+H_{2}O} }$

In organic synthesis, the compound is used as a reagent to introduce nitrogen into organic molecules. The reaction with alcohols gives tertiary amines .

${\displaystyle \mathrm {CH_{3}COONH_{4}+RCH_{2}OH\ {\xrightarrow[{}]{Ir-Katalysator}}\ N(CH_{2}R)_{3}} }$

A one-pot reaction with substituted benzoins , 1,3-dicarbonyl compounds and ammonium acetate leads to tetrasubstituted pyrroles without a solvent or catalyst .

As a variant of the Hantzsch dihydropyridine synthesis , substituted 1,4-dihydropyridines can be obtained by reacting β-ketocarboxylic acid esters, aldehydes and ammonium acetate.

Individual evidence

1. ↑ ^{a b c d e f} Entry on ammonium acetate in the GESTIS substance database of the IFA , accessed on December 19, 2019 (JavaScript required)
2. ↑ Entry on ammonium acetate. In: Römpp Online . Georg Thieme Verlag, accessed on September 29, 2014.
3. ↑ RJ Williams, CM Lyman: A Neutral Buffered Standard for Hydrogen Ion Work and Accurate Titrations Which Can be Prepared in One Minute. In: J. Am. Chem. Soc. 54 (5), 1932, pp. 1911-1912. doi: 10.1021 / ja01344a025
4. ↑ ^{a b c d e} Ammonium acetate. In: e-EROS Encyclopedia of Reagents for Organic Synthesis . John Wiley and Sons, 1999-2013, accessed February 17, 2018.
5. ^ R. Yamaguchi, S. Kawagoe, C. Asai, K. Fujita: Selective Synthesis of Secondary and Tertiary Amines by Cp * Iridium-Catalyzed Multialkylation of Ammonium Salts with Alcohols. In: Org. Lett. 10, 2008, pp. 181-184. doi: 10.1021 / ol702522k .
6. ^ SI Bhat, DR Trivedi: A catalyst- and solvent-free three-component reaction for the regioselective one-pot access to polyfunctionalized pyrroles. In: Tetrahedron Lett. 54, 2013, pp. 5577-5582. doi: 10.1016 / j.tetlet.2013.07.153 .
7. ↑ K. Azizi, J. Azarnia, M. Karimi, E. Yazdani, A. Heydari: Novel Magnetically Separable Sulfated Boric Acid Functionalized Nanoparticles for Hantzsch Ester Synthesis. In: Synlett . 27, 2016, pp. 1810-1813. doi: 10.1055 / s-0035-1561441 .