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Ammonia


Other Names:

Azane







General Information:


Structure:



CAS Number: 7664-41-7

Molecular Weight: 17.031 g/mol

Appearance: Colorless gas

Chemical Formula: NH3

Melting Point: -78 C

Boiling Point: -33 C

Acidity (Pka): 32.5

Basicity (Pkb): 4.75


Ammonia (NH3) has a strong pungent odor. It is a gas at room temperature and is lighter than air. Ammonia is often stored as a liquid in high pressure tanks. In organic chemistry labs ammonia is often used in other, more easy to handle forms. For example, liquid sources of ammonia are ammonium hydroxide (NH4OH) and ammonia in MeOH (typically 2N or 7N). The most common solid source of ammonia is ammonium chloride (NH4Cl).


Note: The examples below include ammonia in its commonly used forms: NH4OH, NH3 in MeOH, and NH4Cl




Common Uses:


Reagent in amide couplings



Procedure excerpt:

To a solution of the SM (1.0 g, 6.4 mmol) in DMF (5.0 mL) at 0 C was added EDC-HCl (1.2 g, 7.7 mmol), NH4Cl (1.4 g, 26.9 mmol), and HOBt (1.1 g, 8.3 mmol). The reaction . . .

[full procedure]




Reagent in the conversion of acid chlorides to amides





Reagent in substitution reactions





Reagent in SNAr reactions



Procedure excerpt:

In a steel pressure vessel was added the SM (3.15 g, 11.1 mmol) and 40% aq NH4OH (21.6 mL, 222 mmol) in dioxane (30 mL) and the mixture was heated . . .

[full procedure]




Reagent in reductive aminations





Additive in the catalytic reduction of nitriles to amines



Procedure excerpt:

A mixture of the SM (180 g, 1.10 mol), Raney Ni (40.0 g), and NH4OH (250 mL) in MeOH (1.0 L) was stirred under H2 (50 psi) at RT for 5 h. The mixture . . .

[full procedure]




Additive in silica gel chromatography



Procedure excerpt:

. . . concentrated in vacuo. The resulting crude material was purified by chromatography [330 g SiO2, 0-5% (10% NH4OH in MeOH)/(DCM)] to provide . . .

[full procedure]




Additive in reverse phase chromatography



Procedure excerpt:

. . . heated with shaking at 90 C overnight. The crude solution was purified by reverse phase chromatography (C18, 5-95% ACN/H2O, 0.1% NH4OH) to provide . . .

[full procedure]




Safety:


Mixing ammonia containing compounds (ex. NH3, NH4OH, or NH4Cl) and bleach (NaOCl) is very dangerous because it produces toxic by-pdts. People have died from mixing cleaning supplies that contain ammonia and bleach. Household cleaning products that contain ammonia are typically aqueous solutions (NH4OH).




References:


1) Patent Reference: WO2014149164, page 227, (23.7 MB)

2) Patent Reference: WO2012149280, page 72, (4.1 MB)

3) Patent Reference: WO2016014463, page 91, (6.7 MB)

4) Patent Reference: WO2015084384, page 62, (4.2 MB)

5) Patent Reference: WO2015051043, page 127, (9.7 MB)

6) Wikipedia: Ammonia (link)

7) www.sigmaaldrich.com: Ammonia (link)

8) The Chlorine Institute, Sodium Hypochlorite Incompatibility Chart (link)