Potassium Hydroxide

General Information:

Structure:

CAS Number: 1310-58-3

Molecular Weight: 56.11 g/mol

Appearance: White solid

Potassium hydroxide (KOH) is a strong base commonly used in organic chemistry. It is typically bought in pellet form as 85% KOH, 15% water. The pKa of the conjugate acid of potassium hydroxide is 15.7. The hydroxide ion is not only a base, it is also an effective nucleophile. It is capable of nucleophilic reactions such as the diplacement of alkyl halides to form alcohols, and the hydrolysis of esters and nitriles to carboxylic acids.

Common Uses:

Reagent for the hydrolysis of esters to carboxylic acids

Reagent for the hydrolysis of nitriles to primary amides

Reagent for the hydrolysis of nitriles to carboxylic acids

Reagent for Wolff-Kishner reactions

Reagent for acetyl deprotection of amines

Reagent for Cbz deprotection of amines

Base for substitution reactions

Base for S_NAr reactions

Base for aldol condensation reactions

Base for iodination reactions

Safety:

Potassium hydroxide (KOH) is a strong base. It reacts readily with acids in exothermic manner. Dissolving potassium hydroxide in water is also an exothermic event and care should be taken. Potassium hydroxide is corrosive and toxic. It is extremely destructive to skin, eyes, and the tissue of the mucous membranes and upper respiratory tract. Potassium hydroxide is incompatible with acids, acid chlorides, acid anhydrides, and aluminum metal. Potassium hydroxide is extremely hygroscopic.

References:

1) Patent Reference: WO2012129338, page 135, (12.0 MB)

2) Patent Reference: WO2012069948, page 63, (3.9 MB)

3) Patent Reference: WO2016014463, page 126, (6.7 MB)

4) US20080293730, page 8

5) Patent Reference: WO2014177977, page 65, (6.0 MB)

6) Patent Reference: WO2016100281, page 98, (10.3 MB)

7) Patent Reference: WO2011014535, page 47, (17.3 MB)

8) Patent Reference: WO2016023832, page 71, (3.2 MB)

9) Patent Reference: WO2012129338, page 84, (12.0 MB)

10) Wikipedia: Potassium hydroxide (link)

11) www.sigmaaldrich.com: Potassium hydroxide (link)

12) Reich, H. J.; Rigby, J. H.; Handbook of Reagents for Organic Synthesis, Acidic and Basic Reagents