Citric Acid

Other Names:

2-hydroxypropane-1,2,3-tricarboxylic acid

General Information:

Structure:

CAS Number: 77-92-9

Molecular Weight: 192.12 g/mol

Appearance: White crystalline solid

Melting Point: 153-159 C

Acidity (pKa): pKa1 = 3.13

pKa2 = 4.76

pKa3 = 6.4

Citric acid is a weak organic acid containing three carboxylic acid functional groups. In organic chemistry it is generally used as an aqueous solution during aqueous work-ups.

Common Uses:

Weak acid for neutralizing reaction mixtures

Procedure Excerpt:

. . . After completion, the reaction mixture was neutralized with 1M aq citric acid (50 mL) and extracted with EtOAc (50 mL). The org layer was . . .

[full procedure]

Weak acid wash for work-ups

Procedure Excerpt:

. . . The resulting mixture was stirred at RT overnight, after which time it was washed successively with 10% aq citric acid, H2O, sat aq Na2CO3, and brine . . .

[full procedure]

References:

1) Patent Reference: WO2014149164, page 337, (23.7 MB)

2) Patent Reference: WO2015158653, page 27, (2.9 MB)

3) Wikipedia: Citric acid (link)

4) www.sigmaaldrich.com: Citric acid (link)