Succinic Acid Structure Properties and Applications

Succinic acid is a dicarboxylic acid. The chemical formula of this acid contains four carbon atoms, six hydrogen atoms, and four oxygen atoms, it is (CH2)2(CO2H)2. Its name is derived from the Latin word “succinum” which means amber. Succinic acid is also known by the name of amber acid as it was first obtained from amber through the distillation method. This dicarboxylic acid takes the form of an anion (succinate ion) in living organisms that possess multiple biological roles. It is also used in the food industry and marketed as food additive E363. It is generated via the tricarboxylic acid cycle (TCA) in mitochondria.

Properties of Succinic Acid

Some of the physical and chemical properties of succinic acid are given below.

• Succinic acid is very acidic in taste, appearance in white, and an odorless solid.

• Succinic Acid is a four-carbon dicarboxylic acid. The succinic acid formula (molecular formula) is C4H6O4.

• Succinic acid molecular weight is 118.09 g/mol.

• The succinic acid melting point is 184^oC.  

• Succinic acid readily ionizes In an aqueous solution to form its conjugate base, called succinate.

• As a diprotic acid (acid contains at least two hydrogen atoms in its molecule that are able to be released or ionized in water)  it undergoes two successive deprotonation reactions that are given below.

(CH2)2(CO2H)2 → (CH2)2(CO2H)(CO2)^- + H⁺

(CH2)2(CO2H)(CO2)^- → (CH2)2(CO2)2^2- + H⁺

The acid dissociation constant of the above two processes is 4.3 and 5.6, respectively. Both anions formed after deprotonation reactions are colorless and can be isolated as salts, for example, their sodium salt would be, Na(CH2)2(CO2H)(CO2) and Na2(CH2)2(CO2)2.

• It is called a succinyl group as a radical group.

• Similar to the most simple mono- and dicarboxylic acids, it is not harmful but can be an irritating substance for skin and eyes.

• It is a polar substance hence it is easily soluble in water, with the solubility at 25 ^oC 1g/13ml at.

• In some organic solvents, it is soluble such as in ethanol (5.4g/100ml) and glycerol (5.0g/100ml) but it is not soluble in ether and petroleum ether.

How is Succinic Acid made?

There are two common manufacturing processes currently in practice for its production. The first one is the traditional chemical synthesis from petroleum-derived raw materials and another is biological-based fermentation from carbohydrates. These processes are mentioned below. 

• Chemical Synthesis

In the commercially chemical synthesis process, succinic acid is obtained from maleic anhydride, obtained by oxidation of n-butane or butadiene. There are two major steps in the chemical synthesis process: First maleic anhydride is catalytic hydrogenated to succinic anhydride and later it reacts with water to form succinic acid. Succinic acid can also prepare fumaric acid hydrogenation.

The following reaction is involved in the production of succinic acid by chemical synthesis.  

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• Bio-based Fermentation

In the year 2014, there was a brief manufacturing process that was based on fermentation used by the manufacturer BioAmber. A gene-modified Pichia sp. strain of Saccharomycetaceae yeast and biomass as the substrate was used for the production of succinic acid. 

Succinic acid is produced by many microorganisms as an intermediate of several biochemical reactions. In ethanol fermentation succinic acid is one of the metabolic co-products. This fermentation is done by the yeast Saccharomyces cerevisiae in addition to lactic acid, glycerol and acetic acid. 

Succinic Acid Structure

Succinic acid is dicarboxylic acid which is formed from the formal oxidation of each of the terminal methyl groups of butane to the corresponding carboxy group. Butanedioic acid is its IUPAC name.  In the citric acid cycle, it is formed as an intermediate metabolite. This process is both expensive as well as harmful to the environment.

The two active methylene groups of succinic acid can be used for the preparation of a lot of complex organic compounds for their reaction characteristics of esterification, halogenation, sulphonation, dehydration, acylation, oxidation, reduction, etc. 

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 Succinic Acid Uses

Some of the important uses of succinic acid are given below.

• This acid is used in a variety of industries such as in the cloth industry in polymers for making clothing fibers, the food industry, surfactants and detergents, flavors, and fragrances.

• It is used for the preparation of a number of important chemicals such as 2-pyrrolidinone, adipic acid, succinate salts, N-methyl pyrrolidinone, 1,4-butanediol, gamma-butyrolactone, maleic anhydride, tetrahydrofuran, etc. 

• Succinic acid has many uses in the pharmaceutical industry. It is an active pharmaceutical ingredient (APIs). It is used as an additive in formulation, succinic acid monoethyl ester (an insulinotropic agent), and a crosslinker in drug control release polymers.

• This chemical plays an important role in the Krebs cycle (intermediary metabolism) in the body. The Krebs cycle is also known as the citric acid cycle which is a sequence process of enzymatic reaction.

Do you know?

In 1546,  through dry distillation (heating in vacuum) of amber, Succinic acid was discovered by Agricola.

Conclusion