Succinic acid

• Butanedioic
• Succinic acid

Colorless and odorless crystalline solid

Fixed

1.55 g · cm -3

184 ° C

235 ° C.

• PKS1 = 4.16
• PKa2 = 5.61

Soluble in water: 58 g · l-1 (20 ° C)

Attention

-940.5 KJ / mol

Template: Infobox chemical / molecular formula search available

Succinic acid, and succinic acid, succinate or succinic acid, E 363, is a colorless, crystalline aliphatic dicarboxylic acid. The crystals are readily soluble in boiling water.

• 5.1 use in the food industry
• 5.2 Technical Uses

History

The succinic acid was discovered in 1546 by Georgius Agricola in the dry distillation by heating amber. Nicolas Lemery first recognized in 1675, the acid nature of the substance and Jöns Jakob Berzelius discovered the composition ( C4H6O4 ) of the acid. Until well into the 20th century medicines were based on succinic acid and its salts for use in catarrh and syphilis in use.

End of the 19th century, who lives in Gdansk pharmacist Otto Helm tried to make reference to its content of succinic acid, the origin of amber. The information obtained in the way of dry distillation and sublimated in retorts acid weighed helmet and came to the conclusion that a proportion of between 3.2% and 8.2%, allow the conclusion that Baltic amber. He examined with this method also Sicilian amber and archaeological finds from Mycenae, among others. While he found no traces of acid in samples of Sicilian amber, reported the antique pieces on an acid content of 4.1 % to 6.3%. Helmet held so that from time immemorial archaeologists employing question concerning the origin of amber finds made ​​in the Mediterranean for answers. It had to act according to these findings by Baltic amber. Later it turned out that the content of succinic acid is not a reliable means of identification of Baltic amber, as well as in other European amber deposits, corresponding concentrations were found to succinic acid. Helms of origin retained, however, validity, since these deposits were not known in the ancient world.

Rolf CA Rottländer came in 1970 to the conclusion of succinic acid was not actually contain naturally in amber, but fancy themselves only in the course of alkaline hydrolysis of amber ( as an alkaline salt) or during dry distillation (as its anhydride ). He suggested to consider succinic acid (as salt or anhydride) as a natural oxidation product of Bernstein and thus as an indicator of the aging process.

The question of the origin of ancient amber from archaeological excavations is therefore still subject to scientific debate and an attempt is made recently by other research methods (infrared spectroscopy, mass spectrometry, gas chromatography, nuclear magnetic resonance [ NMR ], and others ) to answer.

Occurrence

The name derives from the succinic acid is the amber, a gem of fossil resin is contained in the succinic acid. Traditionally was the differentiation of various succinic types on the basis of chemical substances, depending on the content of succinic acid in succinite (3% to 8 %) and retinite (fossil resins having a content of succinic acid of less than 3 % or no succinic acid). In many lignite succinic acid is included.

In the metabolism of organisms, the salt of succinic acid is in the degradation of glucose as an intermediate step in the regeneration of the acceptor oxaloacetic before. Accordingly, it is a metabolic intermediate in the citric acid cycle, as well as it occurs in the urea cycle. In nature, succinic acid also comes in many plant juices before ( rhubarb, tomatoes) as well as in algae and fungi.

Succinic acid can also be an end product of metabolism in some anaerobic living bacteria, such as in the bovine rumen. This represents a system in which a number of anaerobic bacteria living their basic food related optional from the digested food. Of the rumen flora, especially fungi contained, the β -glucosidic bonds of cellulose are broken up in the food. The resulting sugar ( glucose ) is used as a substrate microorganisms. The products of bacterial metabolism are primarily short chain carboxylic acids such as acetic acid and succinic acid as well as ethanol. The bacterially produced succinic acid in turn serves as an energy source for other bacteria that convert to propionic acid.

Production and representation

Technically

Technically different synthetic routes for the production of succinic acid are known. The preparation is generally carried out via a catalytic hydrogenation of maleic acid, maleic anhydride or fumaric acid, using various catalysts can be used (Ni, Cu, NiO, CuZnCr, Pd -Al2O3, Pd - CaCO3). 20,000 to 30,000 tons of succinic acid are produced per year via this pathway.

In addition, the oxidation of 1,4-butanediol ( BDO) is possible, whereby various technical paths exist. The hydrocarboxylation of acetylene catalyzed via RhCl3 - pentachlorothiophenol, acetylene, acrylic acid, 1,4-dioxane and propiolactone is possible.

Biotechnological

Succinic acid can be produced by fermentation of carbohydrates, especially starch and various oligosaccharides ( C6 and C5 sugars ). Here, the natural occurrence of succinic acid can be used in metabolism, to make them produce targeted by microorganisms. Biotechnologically produced succinic acid is used primarily for use in foods, but there are now also pilot plants for biotechnological production of succinic acid for technical applications.

Biotechnology to produce on a large scale due to the possibility of succinic acid with the aid of bacteria is enhanced research with Basfia succiniciproducens, Mannheimia succiniciproducens and Anaerobiospirillum succiniciproducens. Also, the model organism Escherichia coli, which is to be optimized by metabolic engineering for the production of high amounts of succinic acid, is the focus of research.

Chemical Properties

Succinate is referred to as the salts and esters of the succinic acid. The term ' succinate ' is derived from the Latin word suc ( c ) inum from Amber. They contain in their crystal lattices, the succinate ion as negatively charged anion. The general formula is a Alkalisuccinats MOOC -CH 2 -CH 2- COOM, M particularly sodium and potassium ions. Alkalisuccinate dissolve readily in water. The Erdalkalisuccinate are difficult, the other Succinate not water soluble. So you can find calcium succinate in unripe fruits or algae. The ester-like succinates can be described by the half- structure formula R -O-CO -CH2-CH2 -CO-O -R.

If succinic acid heated, it gives off water and forms a ring closing the succinic anhydride.

Use

Use in the food industry

Succinic acid is approved in the EU as a food additive under the E number 363 and is due to the mildly acidic and at the same time slightly salty taste as a flavor enhancer for desserts, dry soups and powdered drinks. As a salt substitute in diet food different salts of succinic acid are used (Fe, Mg, Ca, K). Because the body's production and metabolism of succinic acid, the use of succinic acid is considered a food additive as safe.

During the alcoholic fermentation and during subsequent expansion of the wine in containers such as wooden barrels or stainless steel container in addition to the central acids of wine ( tartaric acid, malic acid and citric acid) are also formed succinic acid and acetic acid, butyric acid and lactic acid. Succinic acid is produced primarily in the carbonic maceration and tastes slightly bitter and salty, the esterification to Monomethylsuccinat brings a mild fruity component in the wine.

Technical uses

Succinic acid is a platform chemical with an annual demand of currently about 15,000 tons and a market value of six to nine euros per kilogram Represent is used eg for the production of polyester and alkyd resins. Some esterified with polyalcohols Succinate is used as solvents and plasticizers for plastics and waxes, other esters are used in the perfume industry. Sulphosuccinic acid esters in the form of succinic acid is used as a major surfactant group, but these are usually made on the basis of maleic acid.

Succinic acid is also one of the main hope for the Industrial Biotechnology as a platform chemical and thus as a raw material for various industrially produced chemicals and polymers. They can be used as feedstock for the biotechnological production bsp. 1,4-butanediol (BDO ), 1,4- butanediamine, tetrahydrofuran (THF), N-methyl -2-pyrrolidone (NMP), γ - butyrolactam, γ -butyrolactone ( GBL) and a number of other products used. Especially as the basis for different products in the chemical and pharmaceutical industries as well as for bio-based plastics such as polyamides ( PA ), polyesters and co- polyesters and polyester amides is succinic acid as a bio-engineered product interesting and it is predicted a market potential of several hundred thousand tons.

Together with other representatives of the C4 - dicarboxylic acids such as fumaric and malic acid, succinic acid was identified accordingly by the Department of Energy of the United States in 2004 as one of twelve platform chemicals with particular biotechnological production potential. Also, in a review of the list of 2010 as one of succinic acid to ten products of the biorefinery technology with the highest potential.