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Ammonium Hydroxide

Other Names:

Aqueous ammonia

Ammonia water

General Information:


CAS Number: 1336-21-6

Molecular Weight: 35.04 g/mol

Appearance: Colorless liquid

Chemical Formula: NH4OH

Melting Point: -57.5 C (25% w/w)

Boiling Point: 37.3 C (25% w/w)

Density: 0.91 g/mL (25% w/w)

Ammonium hydroxide (NH4OH) solutions are basic, with a 1M NH3 solution having a pH of 11.63. Saturated NH4OH solutions contain 35% ammonia (by mass), however, concentrated solutions that are used in organic chemistry labs are typically 28-30% ammonia (by mass). The concentration of ammonia decreases slightly every time a bottle is opened due to evaporation of ammonia, especially if the bottle was removed from a refrigerator and allowed to warm to room temperature.

Common Uses:

Reagent in amide coupling reactions (serves as a source of NH3)

Nucleophile in SNAr reactions

Additive in the catalytic reduction of nitriles

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…

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…


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).


1) WO2014149164, page 213

2) WO2012149280, page 72

3) WO2016014463, page 91

4) WO2015084384, page 62

5) WO2015051043, page 127

6) Wikipedia: Ammonium hydroxide (link)

7) Ammonium hydroxide solution (link)

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