77-92-9 Usage
Description
Citric acid is a white, crystalline, weak organic acid that is naturally present in most plants and many animals as an intermediate in cellular respiration. It is derived from citrus fruits and has astringent and antioxidant properties. Citric acid is a tricarboxylic acid with the formula C6H8O7 and is an important metabolite in the pathway of all aerobic organisms. It is a natural preservative, pH adjuster, and is used to add an acidic or sour taste to foods and soft drinks.
Uses
Used in Food and Beverage Industry:
Citric acid is used as an acidulant for adding a sour taste to fruit drinks and carbonated beverages at 0.25-0.40%, in cheese at 3-4%, and in jellies. It is also used as a flavoring agent and a chelating agent.
Used in Pharmaceutical Industry:
Citric acid is used as a product stabilizer, pH adjuster, and preservative with a low sensitizing potential. It is not usually irritating to normal skin but can cause burning and redness when applied to chapped, cracked, or inflamed skin.
Used in Cosmetics Industry:
Citric acid is used in the formulation of cosmetics due to its astringent and antioxidant properties.
Used in Biotechnology:
Citric acid is involved in the citric acid cycle, which is central to nearly all metabolic reactions and is the source of two-thirds of the food-derived energy in higher organisms.
Used in Chemical Restraint:
Citric acid was also used as a chemical restrainer, particularly in developers for the collodion process and in silver nitrate solutions used for sensitizing salted and albumen papers.
Used in Antioxidant Applications:
Citric acid is used as an antioxidant in instant potatoes, wheat chips, and potato sticks, where it prevents spoilage by trapping metal ions. It is also used in combination with antioxidants in the processing of fresh frozen fruits to prevent discoloration.
Used in Industrial Production:
Citric acid is produced by mycological fermentation on an industrial scale using crude sugar solutions, such as molasses and strains of Aspergillus niger. It is a commodity chemical, with more than a million tonnes produced every year, and is widely distributed in plants and animal tissues and fluids.
History
The discovery of citric acid is credited to Jabir ibn Hayyan (Latin name Geber, 721–815). Citric acid was first isolated in 1784 by the Swedish chemist Carl Wilhelm Scheele (1742–1786), who crystallized it from lemon juice.The crystalline structure of anhydrous citric acid, obtained by cooling hot concentrated solution of the monohydrate form, was first elucidated by Yuill and Bennett in 1934 by X-ray diffraction.In 1960 Nordman and co-workers further suggested that in the anhydrous form two molecules of the acid are linked through hydrogen bonds between two –COOH groups of each monomer.
Preparation
By mycological fermentation using molasses and strains of Aspergillus niger; from citrus juices and pineapple wastes
Biotechnological Production
Fermentation is the technology of choice for citric acid synthesis. Different bacteria
(e.g. Arthrobacter paraffinens and Bacillus licheniformis), filamentous fungi
(e.g. Aspergilus niger and Penicillium citrinum) and yeasts (e.g. Candida tropicalis
and Yarrowia lipolytica) are able to produce citric acid. Due to high
productivity and easy handling, citric acid is usually produced by fermentation
with A. niger. For example, a product concentration of 114 g.L-1 within
168 h has been reached by cultivation of A. niger GCMC 7 on cane molasses
. On the industrial scale, submerged cultivation, surface fermentation and
solid-state fermentation are used.
In general, molasses, starch hydrolyzate and starch are used as substrates.
However, there are various studies for alternative raw materials. Solid-state
fermentation of inexpensive agricultural wastes is one possibility. For
example, high yields up to 88 % have been achieved using grape pomace as
substrate. Lowering the cost of product recovery is crucial. Different methods
using precipitation, solvent extraction, adsorption, or in situ product recovery have
been described. One interesting process could be the in situ crystallization of
citric acid during fermentation to improve the economics.
benefits
Citric acid is not a vitamin or mineral and is not required in the diet. However, citric acid, not to be confused with ascorbic acid (vitamin C), is beneficial for people with kidney stones. It inhibits stone formation and breaks up small stones that are beginning to form. Citric acid is protective; the more citric acid in your urine, the more protected you are against forming new kidney stones. Citrate, used in calcium citrate supplements and in some medications (such as potassium citrate), is closely related to citric acid and also has stone prevention benefits. These medications may be prescribed to alkalinize your urine.
Air & Water Reactions
The pure material is moisture sensitive (undergoes slow hydrolysis) Water soluble.
Reactivity Profile
Citric acid reacts with oxidizing agents, bases, reducing agents and metal nitrates . Reactions with metal nitrates are potentially explosive. Heating to the point of decomposition causes emission of acrid smoke and fumes [Lewis].
Biochem/physiol Actions
Citric acid in dietary form can augments absorption of aluminium in antacids. It also facilitates the phytoremediation of heavy metal contaminated soil and can transform cadmium into more transportable forms.
Safety Profile
Poison by intravenous
route. Moderately toxic by subcutaneous
and intraperitoneal routes. Mildly toxic byingestion. A severe eye and moderate skin
irritant. An irritating organic acid, some
allergenic properties. Combustible liquid.
Potentially explosive reaction with metal
nitrates. When heated to decomposition it
emits acrid smoke and fumes.
Check Digit Verification of cas no
The CAS Registry Mumber 77-92-9 includes 5 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 2 digits, 7 and 7 respectively; the second part has 2 digits, 9 and 2 respectively.
Calculate Digit Verification of CAS Registry Number 77-92:
(4*7)+(3*7)+(2*9)+(1*2)=69
69 % 10 = 9
So 77-92-9 is a valid CAS Registry Number.
InChI:InChI=1/C6H8O7/c7-3(8)1-6(13,5(11)12)2-4(9)10/h13H,1-2H2,(H,7,8)(H,9,10)(H,11,12)/p-3
77-92-9Relevant articles and documents
-
Warneford,Hardy
, (1926)
-
Discovery and Biosynthesis of Bolagladins: Unusual Lipodepsipeptides from Burkholderia gladioli Clinical Isolates**
Challis, Gregory L.,Dashti, Yousef,Jian, Xinyun,Mahenthiralingam, Eshwar,Mullins, Alex J.,Nakou, Ioanna T.,Webster, Gordon
, (2020)
Two Burkholderia gladioli strains isolated from the lungs of cystic fibrosis patients were found to produce unusual lipodepsipeptides containing a unique citrate-derived fatty acid and a rare dehydro-β-alanine residue. The gene cluster responsible for the
SYNTHESIS OF 4-(HYDROXYMETHYL)TETRAHYDRO-4-PYRANOL - A NEW INTERMEDIATE FOR THE PREPARATION OF SYNTHETIC CITRIC ACID
Gevorkyan, A. A.,Kazaryan, P. I.,Sargysyan, M. S.,Petrosyan, K. A.,Mkrtumyan, S. A.
, p. 712 - 713 (1983)
The hydroxylation of 4-methylenetetrahydropyran with hydrogen peroxide in the presence of various acidic catalysts was investigated.The oxidation of 4-(hydroxymethyl)tetrahydro-4-pyranol with concentrated nitric acid leads to citric acid in 50percent yield.
Absolute stereochemical course of the 3-carboxymuconate cycloisomerases from Pseudomonas putida and Acinetobacter colcoaceticus: Analysis and implications
Chari,Whitman,Kozarich,et al.
, p. 5514 - 5519 (1987)
The absolute stereochemical course of the 3-carboxymuconate cycloisomerases [EC 5.5.1.2; 2-carboxy-5-oxo-2,5-dihydrofuran-2-acetate lyase (decyclizing)] from Pseudomonas putida and Acinetobacter calcoaceticus has been determined by chemical and 1H NMR methods. The product of the enzyme-catalyzed reaction in 2H2O was detected by NMR and trapped by catalytic hydrogenation to afford 5-[2H]homocitrate lactone. Subsequent chemical degradation of the monodeuteriated homocitrate lactone gave (2r,3S)-2-[2H]citrate as determined by 1H NMR analysis. The product of the cycloisomerase reaction was established as (4R,5R)-5-[2H]-4-carboxymuconate, indicating that the lactonization proceeded by an anti addition - the mechanistic and stereochemical antipode of the previously studied muconate cycloisomerase from P. putida and 3-carboxymuconate cycloisomerase from Neurospora crassa. The anti addition probably represents the lower energy pathway for the reaction and suggests that the evolutionary relationship between the two classes of cycloisomerases is more remote than previously believed.
Kusnetzow
, p. 341 (1925)
Cyanide as a primordial reductant enables a protometabolic reductive glyoxylate pathway
Krishnamurthy, Ramanarayanan,Pulletikurti, Sunil,Yadav, Mahipal,Yerabolu, Jayasudhan R.
, p. 170 - 178 (2022/02/11)
Investigation of prebiotic metabolic pathways is predominantly based on abiotically replicating the reductive citric acid cycle. While attractive from a parsimony point of view, attempts using metal/mineral-mediated reductions have produced complex mixtures with inefficient and uncontrolled reactions. Here we show that cyanide acts as a mild and efficient reducing agent mediating abiotic transformations of tricarboxylic acid intermediates and derivatives. The hydrolysis of the cyanide adducts followed by their decarboxylation enables the reduction of oxaloacetate to malate and of fumarate to succinate, whereas pyruvate and α-ketoglutarate themselves are not reduced. In the presence of glyoxylate, malonate and malononitrile, alternative pathways emerge that bypass the challenging reductive carboxylation steps to produce metabolic intermediates and compounds found in meteorites. These results suggest a simpler prebiotic forerunner of today’s metabolism, involving a reductive glyoxylate pathway without oxaloacetate and α-ketoglutarate—implying that the extant metabolic reductive carboxylation chemistries are an evolutionary invention mediated by complex metalloproteins. [Figure not available: see fulltext.].
Catalytic Oxidation of VOCs over SmMnO3 Perovskites: Catalyst Synthesis, Change Mechanism of Active Species, and Degradation Path of Toluene
Liu, Lizhong,Sun, Jiangtian,Ding, Jiandong,Zhang, Yan,Jia, Jinping,Sun, Tonghua
, p. 14275 - 14283 (2019/10/17)
Highly active samarium manganese perovskite oxides were successfully prepared by employing self-molten-polymerization, coprecipitation, sol-gel, and impregnation methods. The physicochemical properties of perovskite oxides were investigated by XRD, N2 adsorption-desorption, XPS, and H2-TPR. Their catalytic performances were compared via the catalytic oxidation of toluene. The perovskite prepared by self-molten-polymerization possessed the highest catalytic capacity, which can be ascribed to its higher oxygen adspecies concentration (Olatt/Oads = 0.53), higher surface Mn4+/Mn3+ ratio (Mn4+/Mn3+ = 0.95), and best low-temperature reducibility (H2 consumption = 0.27; below 350 °C). The most active catalyst also exhibited good cycling and long-term stability for toluene oxidation. After a multistep cycle reaction and a long-term reaction of 42 h, the toluene conversion maintained above 99.9% at 270 °C. Mechanistic study hinted that lattice oxygen was involved in toluene oxidation. The oxidation reaction was dependent on the synergism of lattice oxygen, adsorbed oxygen, and oxygen vacancies. The degradation pathway of toluene, researched by diffuse reflectance infrared Fourier transform spectroscopy and online mass spectrometry technologies, demonstrated that a series of organic byproducts existed at a relatively low temperature. This work provides an efficient and practical method for selecting highly active catalysts and for exploring the catalytic mechanism for the removal of atmospheric environmental pollution.
