What's Sorbic acid ?

Sorbic acid is a white crystalline solid. It has a melting point of 134.5°C, a boiling point of 228°C and a pKa of 4.76.The chemistry of sorbic acid is determined by the carboxyl group and the conjugate double bonds.



Sorbic acid, or 2,4-hexadienoic acid, is a natural organic compound used as a food preservative. It has the chemical formula C6H8O2. It is a white crystalline solid that is slightly soluble in water and sublimes readily. It has a melting point of 134.5°C, a boiling point of 228°C and a pKa of 4.76. The chemistry of sorbic acid is determined by the carboxyl group and the conjugate double bonds.  It was first isolated from the unripe berries of the rowan tree (Sorbus aucuparia), hence its name.

Sorbic acid can be inactivated by oxidation and to some extent by nonionic surfactants and plastics. The activity of the sorbates may be reduced by increases in pH. Sorbic acids are relatively ineffective above a pH of 6.5.
Sorbic acid and its mineral salts, such as sodium sorbate, potassium sorbate and calcium sorbate, are antimicrobial agents often used as preservatives in food and drinks to prevent the growth of mold, yeast, and fungi. In general, the salts are preferred over the acid form because they are more soluble in water.

The un-dissociated sorbic acid molecule is responsible for the inhibitory effect of this compound. The exact mechanism of this inhibitory effect is unknown. Most scientists propose that it is not possible for food cells to develop resistance to sorbic acid. However, the break down time of sorbic acid is not known; the unknown mechanisms, expiration date, and effects of sorbic acid and its derivatives have caused concern among some people. These issues are under investigation by the scientific community.


1.Sorbic acid Chemical Properties

Product Name: Sorbic acid

Synonyms: 2-PROPENYL ACRYLIC ACID;2,4-HEXANEDIENOIC ACID;2,4-HEXADIENOIC ACID;1,3-Pentadiene-1-carboxylic acid;ACIDUM SORBICUM;(E,E) 2,4-HEXADIENOIC ACID;FEMA 3921;Hexa-2,4-dienoic acid

CAS: 110-44-1

MF: C6H8O2

MW: 112.13

EINECS: 203-768-7

mp:  132-135 °C(lit.)

bp:  228°C

density:  1,205 g/cm3

vapor pressure:  0.01 mm Hg ( 20 °C)

FEMA:  3921

Fp : 127 °C 

storage temp:2-8°C

solubility  ethanol: 0.1 g/mL, clear

Water Solubility : 1.6 g/L (20 ºC)

Merck : 14,8721

BRN : 1741831

Stability: Stability Material saturated with this acid may ignite spontaneously. Incompatible with strong oxidizing agents. May be light sensitive.

CAS DataBase Reference: 110-44-1

NIST Chemistry Reference :2,4-Hexadienoic acid, (E,E)-(110-44-1)

EPA Substance Registry System: 2,4-Hexadienoic acid, (2E,4E)-(110-44-1)


2.Safety Information
Hazard Codes : Xi

Risk Statements: 36/37/38-36/38

Safety Statements : 26-36-24/25

WGK Germany : 1

RTECS : WG2100000

F: 8

HS Code:  29161930

Hazardous Substances Data: 110-44-1

Safety: Sorbic acid may be an irritant. An allergic reaction to sorbic acid may occur if it is inhaled, ingested or in contact with the skin. Inhalation or ingestion of pure sorbic acid should be considered a medical emergency.