Potassium Carbonate

General Information:

Structure:

CAS Number: 584-08-7

Molecular Weight: 138.21 g/mol

Appearance: White solid

Chemical Formula: K2CO3

Melting Point: 891 C

Potassium carbonate (K2CO3) is a commonly used base in organic chemistry. The pKa of its conjugate acid is 10.25. It is commonly used to deprotonate moderately acidic protons such as phenols (pKa ~10) and 1,3-dicarbonyl compounds (pKa ~9-13). Potassium carbonate has high solubility in water (1.12 g/mL, at 20 C), and has low solubility in ethanol, acetone, and many other common organic solvents.

Common Uses:

- Base for alkylations (including Benzyl Protections, SEM Protections, and Cbz Protections)

- Base for Pd Coupling reactions

- Base to neutralize acidic reaction mixtures prior to workup

Safety:

Potassium carbonate is considered a weak base. Avoid contact with skin and eyes. Potassium carbonate is relatively non-toxic.

References:

1) Wikipedia: Potassium carbonate (link)

2) www.sigmaaldrich.com: Potassium carbonate (link)

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