Potassium Hydroxide (KOH) is a Strong Base
Potassium hydroxide (KOH) is a strong base commonly used in organic chemistry. 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 typically bought in pellet form as 85% KOH – official statement – , 15% water. 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 SNAr reactions
Base for aldol condensation reactions
Base for iodination reactions
Safety:
Potassium hydroxide (KOH) is a strong base. Dissolving potassium hydroxide in water is also an exothermic event and care should be taken. Potassium hydroxide is corrosive and toxic. It reacts readily with acids in exothermic manner. Potassium hydroxide is incompatible with acids, acid chlorides, acid anhydrides, and aluminum metal. It is extremely destructive to skin, eyes, and the tissue of the mucous membranes and upper respiratory tract. 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.
