In organic chemistry, a dicarboxylic acid is an organic compound containing two carboxyl groups (−COOH). The general molecular formula for dicarboxylic acids can be written as HO2C−R−CO2H, where R can be aliphatic or aromatic. In general, dicarboxylic acids show similar chemical behavior and reactivity to monocarboxylic acids.
Dicarboxylic acids are used in the preparation of copolymers such as polyamides and polyesters. The most widely used dicarboxylic acid in the industry is adipic acid, which is a precursor in the production of nylon. Other examples of dicarboxylic acids include aspartic acid and glutamic acid, two amino acids in the human body. The name can be abbreviated to diacid; long chain aliphatic dicarboxylic acids are known as fatty diacids.
The general formula for acyclic dicarboxylic acid is HO
2C(CH
2)
nCO
2H. [1] The PubChem links gives access to more information on the compounds, including other names, ids, toxicity and safety.
Acids from the two-carbon oxalic acid to the ten-member sebacic acid may be remembered using the mnemonic 'Oh My Son, Go And Pray Softly And Silently', and also 'Oh my! Such great Apple Pie, sweet as sugar!'.
C | n | Common name | Systematic IUPAC name | Structure | pKa1 | pKa2 | PubChem |
---|---|---|---|---|---|---|---|
C2 | 0 | Oxalic acid | ethanedioic acid | ![]() | 1.27 | 4.27 | 971 |
C3 | 1 | Malonic acid | propanedioic acid | ![]() | 2.85 | 5.05 | 867 |
C4 | 2 | Succinic acid | butanedioic acid | ![]() | 4.21 | 5.41 | 1110 |
C5 | 3 | Glutaric acid | pentanedioic acid | ![]() | 4.34 | 5.41 | 743 |
C6 | 4 | Adipic acid | hexanedioic acid | ![]() | 4.41 | 5.41 | 196 |
C7 | 5 | Pimelic acid | heptanedioic acid | ![]() | 4.50 | 5.43 | 385 |
C8 | 6 | Suberic acid | octanedioic acid | ![]() | 4.526 | 5.498 | 10457 |
C8 | 6 | 1,4-Cyclohexanedicarboxylic acid | ![]() | 14106 | |||
C9 | 7 | Azelaic acid | nonanedioic acid | ![]() | 4.550 | 5.498 | 2266 |
C10 | 8 | Sebacic acid | decanedioic acid | ![]() | 4.720 | 5.450 | 5192 |
C11 | 9 | undecanedioic acid | ![]() | 15816 | |||
C12 | 10 | dodecanedioic acid | ![]() | 12736 | |||
C13 | 11 | Brassylic acid | tridecanedioic acid | ![]() | 10458 | ||
C16 | 14 | Thapsic acid | hexadecanedioic acid | ![]() | 10459 | ||
C21 | 19 | Japanic acid | heneicosanedioic acid | 9543668 | |||
C22 | 20 | Phellogenic acid | docosanedioic acid | ![]() | 244872 | ||
C30 | 28 | Equisetolic acid | triacontanedioic acid | 5322010 |
Japan wax is a mixture containing triglycerides of C21, C22 and C23 dicarboxylic acids obtained from the sumac tree (Rhus sp.).
A large survey of the dicarboxylic acids present in Mediterranean nuts revealed unusual components. [6] A total of 26 minor acids (from 2 in pecan to 8% in peanut) were determined: 8 species derived from succinic acid, likely in relation with photosynthesis, and 18 species with a chain from 5 to 22 carbon atoms. Higher weight acids (>C20) are found in suberin present at vegetal surfaces (outer bark, root epidermis). C16 to C26 α,ω-dioic acids are considered as diagnostic for suberin. With C18:1 and C18:2, their content amount from 24 to 45% of whole suberin. They are present at low levels (< 5%) in plant cutin, except in Arabidopsis thaliana where their content can be higher than 50%. [7]
It was shown that hyperthermophilic microorganisms specifically contained a large variety of dicarboxylic acids. [8] This is probably the most important difference between these microorganisms and other marine bacteria. Dioic fatty acids from C16 to C22 were found in an hyperthermophilic archaeon, Pyrococcus furiosus . Short and medium chain (up to 11 carbon atoms) dioic acids have been discovered in Cyanobacteria of the genus Aphanizomenon . [9]
Dicarboxylic acids may be produced by ω-oxidation of fatty acids during their catabolism. It was discovered that these compounds appeared in urine after administration of tricaprin and triundecylin. Although the significance of their biosynthesis remains poorly understood, it was demonstrated that ω-oxidation occurs in rat liver but at a low rate, needs oxygen, NADPH and cytochrome P450. It was later shown that this reaction is more important in starving or diabetic animals where 15% of palmitic acid is subjected to ω-oxidation and then tob-oxidation, this generates malonyl-CoA which is further used in saturated fatty acid synthesis. [10] The determination of the dicarboxylic acids generated by permanganate-periodate oxidation of monoenoic fatty acids was useful to study the position of the double bond in the carbon chain. [11]
Long-chain dicarboxylic acids containing vicinal dimethyl branching near the centre of the carbon chain have been discovered in the genus Butyrivibrio , bacteria which participate in the digestion of cellulose in the rumen. [12] These fatty acids, named diabolic acids, have a chain length depending on the fatty acid used in the culture medium. The most abundant diabolic acid in Butyrivibrio had a 32-carbon chain length. Diabolic acids were also detected in the core lipids of the genus Thermotoga of the order Thermotogales, bacteria living in solfatara springs, deep-sea marine hydrothermal systems and high-temperature marine and continental oil fields. [13] It was shown that about 10% of their lipid fraction were symmetrical C30 to C34 diabolic acids. The C30 (13,14-dimethyloctacosanedioic acid) and C32 (15,16-dimethyltriacontanedioic acid) diabolic acids have been described in Thermotoga maritima. [14]
Some parent C29 to C32 diacids but with methyl groups on the carbons C-13 and C-16 have been isolated and characterized from the lipids of thermophilic anaerobic bacterium Thermoanaerobacter ethanolicus . [15] The most abundant diacid was the C30 α,ω-13,16-dimethyloctacosanedioic acid.
Biphytanic diacids are present in geological sediments and are considered as tracers of past anaerobic oxidation of methane. [16] Several forms without or with one or two pentacyclic rings have been detected in Cenozoic seep limestones. These lipids may be unrecognized metabolites from Archaea.
Crocetin is the core compound of crocins (crocetin glycosides) which are the main red pigments of the stigmas of saffron ( Crocus sativus ) and the fruits of gardenia ( Gardenia jasminoides ). Crocetin is a 20-carbon chain dicarboxylic acid which is a diterpenenoid and can be considered as a carotenoid. It was the first plant carotenoid to be recognized as early as 1818 while the history of saffron cultivation reaches back more than 3,000 years. The major active ingredient of saffron is the yellow pigment crocin 2 (three other derivatives with different glycosylations are known) containing a gentiobiose (disaccharide) group at each end of the molecule. A simple and specific HPLC-UV method has been developed to quantify the five major biologically active ingredients of saffron, namely the four crocins and crocetin. [17]
Type | Common name | IUPAC name | Isomer | Structural formula | PubChem |
---|---|---|---|---|---|
Monounsaturated | Maleic acid | (Z)-Butenedioic acid | cis | ![]() | 444266 |
Fumaric acid | (E)-Butenedioic acid | trans | ![]() | 444972 | |
Acetylenedicarboxylic acid | But-2-ynedioic acid | not applicable | ![]() | 371 | |
Glutaconic acid | (Z)-Pent-2-enedioic acid | cis | ![]() | 5370328 | |
(E)-Pent-2-enedioic acid | trans | ![]() | 5280498 | ||
2-Decenedioic acid | trans | ![]() | 6442613 | ||
Traumatic acid | Dodec-2-enedioic acid | trans | ![]() | 5283028 | |
Diunsaturated | Muconic acid | (2E,4E)-Hexa-2,4-dienedioic acid | trans,trans | ![]() | 5356793 |
(2Z,4E)-Hexa-2,4-dienedioic acid | cis,trans | ![]() | 280518 | ||
(2Z,4Z)-Hexa-2,4-dienedioic acid | cis,cis | ![]() | 5280518 | ||
Glutinic acid (Allene-1,3-dicarboxylic acid) | (RS)-Penta-2,3-dienedioic acid | HO2CCH=C=CHCO2H | 5242834 | ||
Branched | Citraconic acid | (2Z)-2-Methylbut-2-enedioic acid | cis | ![]() | 643798 |
Mesaconic acid | (2E)-2-Methyl-2-butenedioic acid | trans | ![]() | 638129 | |
Itaconic acid | 2-Methylidenebutanedioic acid | – | ![]() | 811 |
Traumatic acid, was among the first biologically active molecules isolated from plant tissues. This dicarboxylic acid was shown to be a potent wound healing agent in plant that stimulates cell division near a wound site, [18] it derives from 18:2 or 18:3 fatty acid hydroperoxides after conversion into oxo- fatty acids.
trans,trans-Muconic acid is a metabolite of benzene in humans. The determination of its concentration in urine is therefore used as a biomarker of occupational or environmental exposure to benzene. [19] [20]
Glutinic acid, a substituted allene, was isolated from Alnus glutinosa (Betulaceae). [21]
While polyunsaturated fatty acids are unusual in plant cuticles, a diunsaturated dicarboxylic acid has been reported as a component of the surface waxes or polyesters of some plant species. Thus, octadeca-c6,c9-diene-1,18-dioate, a derivative of linoleic acid, is present in Arabidopsis and Brassica napus cuticle. [22]
Several dicarboxylic acids having an alkyl side chain and an itaconate core have been isolated from lichens and fungi, itaconic acid (methylenesuccinic acid) being a metabolite produced by filamentous fungi. Among these compounds, several analogues, called chaetomellic acids with different chain lengths and degrees of unsaturation have been isolated from various species of the lichen Chaetomella. These molecules were shown to be valuable as basis for the development of anticancer drugs due to their strong farnesyltransferase inhibitory effects. [23]
A series of alkyl- and alkenyl-itaconates, known as ceriporic acids (Pub Chem 52921868), were found in cultures of a selective lignin-degrading fungus (white rot fungus), Ceriporiopsis subvermispora. [24] [25] The absolute configuration of ceriporic acids, their stereoselective biosynthetic pathway and the diversity of their metabolites have been discussed in detail. [26]
Common name | IUPAC name | Structural formula | PubChem |
---|---|---|---|
Tartronic acid | 2-Hydroxypropanedioic acid | ![]() | 45 |
Mesoxalic acid | Oxopropanedioic acid | ![]() | 10132 |
Malic acid | Hydroxybutanedioic acid | ![]() | 525 |
Tartaric acid | 2,3-Dihydroxybutanedioic acid | ![]() | 875 |
Oxaloacetic acid | Oxobutanedioic acid | ![]() | 970 |
Aspartic acid | 2-Aminobutanedioic acid | ![]() | 5960 |
dioxosuccinic acid | dioxobutanedioic acid | ![]() | 82062 |
α-hydroxyGlutaric acid | 2-hydroxypentanedioic acid | ![]() | 43 |
Arabinaric acid | 2,3,4-Trihydroxypentanedioic acid | 109475 | |
Acetonedicarboxylic acid | 3-Oxopentanedioic acid | ![]() | 68328 |
α-Ketoglutaric acid | 2-Oxopentanedioic acid | ![]() | 51 |
Glutamic acid | 2-Aminopentanedioic acid | ![]() | 611 |
Diaminopimelic acid | (2R,6S)-2,6-Diaminoheptanedioic acid | ![]() | 865 |
Saccharic acid | (2S,3S,4S,5R)-2,3,4,5-Tetrahydroxyhexanedioic acid | ![]() | 33037 |
Common names | IUPAC name | Structure | PubChem |
---|---|---|---|
Phthalic acid o-phthalic acid | Benzene-1,2-dicarboxylic acid | ![]() | 1017 |
Isophthalic acid m-phthalic acid | Benzene-1,3-dicarboxylic acid | ![]() | 8496 |
Terephthalic acid p-phthalic acid | Benzene-1,4-dicarboxylic acid | ![]() | 7489 |
Diphenic acid Biphenyl-2,2′-dicarboxylic acid | 2-(2-Carboxyphenyl)benzoic acid | ![]() | 10210 |
2,6-Naphthalenedicarboxylic acid | 2,6-Naphthalenedicarboxylic acid | ![]() | 14357 |
Terephthalic acid is a commodity chemical used in the manufacture of the polyester known by brand names such as PET, Terylene, Dacron and Lavsan.
Dicarboxylic acids are crystalline solids. Solubility in water and melting point of the α,ω- compounds progress in a series as the carbon chains become longer with alternating between odd and even numbers of carbon atoms, so that for even numbers of carbon atoms the melting point is higher than for the next in the series with an odd number. [27] These compounds are weak dibasic acids with pKa tending towards values of ca. 4.5 and 5.5 as the separation between the two carboxylate groups increases. Thus, in an aqueous solution at pH about 7, typical of biological systems, the Henderson–Hasselbalch equation indicates they exist predominantly as dicarboxylate anions.
The dicarboxylic acids, especially the small and linear ones, can be used as crosslinking reagents. [28] Dicarboxylic acids where the carboxylic groups are separated by none or one carbon atom decompose when they are heated to give off carbon dioxide and leave behind a monocarboxylic acid. [27]
Blanc's Rule says that heating a barium salt of a dicarboxylic acid, or dehydrating it with acetic anhydride will yield a cyclic acid anhydride if the carbon atoms bearing acid groups are in position 1 and (4 or 5). So succinic acid will yield succinic anhydride. For acids with carboxylic groups at position 1 and 6 this dehydration causes loss of carbon dioxide and water to form a cyclic ketone, for example, adipic acid will form cyclopentanone. [27]
As for monofunctional carboxylic acids, derivatives of the same types exist. However, there is the added complication that either one or two of the carboxylic groups could be altered. If only one is changed then the derivative is termed "acid", and if both ends are altered it is called "normal". These derivatives include salts, chlorides, esters, amides, and anhydrides. In the case of anhydrides or amides, two of the carboxyl groups can come together to form a cyclic compound, for example succinimide. [29]
In chemistry, particularly in biochemistry, a fatty acid is a carboxylic acid with an aliphatic chain, which is either saturated or unsaturated. Most naturally occurring fatty acids have an unbranched chain of an even number of carbon atoms, from 4 to 28. Fatty acids are a major component of the lipids in some species such as microalgae but in some other organisms are not found in their standalone form, but instead exist as three main classes of esters: triglycerides, phospholipids, and cholesteryl esters. In any of these forms, fatty acids are both important dietary sources of fuel for animals and important structural components for cells.
Lipids are a broad group of organic compounds which include fats, waxes, sterols, fat-soluble vitamins, monoglycerides, diglycerides, phospholipids, and others. The functions of lipids include storing energy, signaling, and acting as structural components of cell membranes. Lipids have applications in the cosmetic and food industries, and in nanotechnology.
Malonic acid (IUPAC systematic name: propanedioic acid) is a dicarboxylic acid with structure CH2(COOH)2. The ionized form of malonic acid, as well as its esters and salts, are known as malonates. For example, diethyl malonate is malonic acid's diethyl ester. The name originates from the Greek word μᾶλον (malon) meaning 'apple'.
In organic chemistry, an acyl halide is a chemical compound derived from an oxoacid by replacing a hydroxyl group with a halide group.
Enoyl-CoA-(∆) isomerase (EC 5.3.3.8, also known as dodecenoyl-CoA- isomerase, 3,2-trans-enoyl-CoA isomerase, ∆3 ,∆2 -enoyl-CoA isomerase, or acetylene-allene isomerase, is an enzyme that catalyzes the conversion of cis- or trans-double bonds of coenzyme A bound fatty acids at gamma-carbon to trans double bonds at beta-carbon as below:
Suberin is a lipophilic, complex polyester biopolymer of plants, composed of long-chain fatty acids called suberin acids and glycerol. Suberin, interconnected with cutins and lignins, also complex macromolecules, form a protective barrier in the epidermal and peridermal cell walls of higher plants. Suberins and lignins are considered covalently linked to lipids and carbohydrates, respectively, and lignin is covalently linked to suberin, and to a lesser extent, to cutin. Suberin is a major constituent of cork, and is named after the cork oak, Quercus suber. Its main function is as a barrier to movement of water and solutes.
Sebacic acid is a naturally occurring dicarboxylic acid with the chemical formula HO2C(CH2)8CO2H. It is a white flake or powdered solid. Sebaceus is Latin for tallow candle, sebum is Latin for tallow, and refers to its use in the manufacture of candles. Sebacic acid is a derivative of castor oil.
Aldaric acids are a group of sugar acids, where the terminal hydroxyl and carbonyl groups of the sugars have been replaced by terminal carboxylic acids, and are characterised by the formula HO2C-(CHOH)n-CO2H. Oxidation of just the aldehyde yields an aldonic acid while oxidation of just the terminal hydroxyl group yields an uronic acid.) Aldaric acids cannot form cyclic hemiacetals like unoxidized sugars, but they can sometimes form lactones.
In organic chemistry, ozonolysis is an organic reaction where the unsaturated bonds are cleaved with ozone. Multiple carbon–carbon bond are replaced by carbonyl groups, such as aldehydes, ketones, and carboxylic acids. The reaction is predominantly applied to alkenes, but alkynes and azo compounds are also susceptible to cleavage. The outcome of the reaction depends on the type of multiple bond being oxidized and the work-up conditions.
An organic acid anhydride is an acid anhydride that is also an organic compound. An acid anhydride is a compound that has two acyl groups bonded to the same oxygen atom. A common type of organic acid anhydride is a carboxylic anhydride, where the parent acid is a carboxylic acid, the formula of the anhydride being (RC(O))2O. Symmetrical acid anhydrides of this type are named by replacing the word acid in the name of the parent carboxylic acid by the word anhydride. Thus, (CH3CO)2O is called acetic anhydride.Mixed (or unsymmetrical) acid anhydrides, such as acetic formic anhydride (see below), are known, whereby reaction occurs between two different carboxylic acids. Nomenclature of unsymmetrical acid anhydrides list the names of both of the reacted carboxylic acids before the word "anhydride" (for example, the dehydration reaction between benzoic acid and propanoic acid would yield "benzoic propanoic anhydride").
Pimelic acid is the organic compound with the formula HO2C(CH2)5CO2H. Pimelic acid is one CH
2 unit longer than a related dicarboxylic acid, adipic acid, a precursor to many polyesters and polyamides. However compared to adipic acid, pimelic acid is relatively small in importance industrially. Derivatives of pimelic acid are involved in the biosynthesis of the amino acid lysine and the vitamin biotin.
Pelargonic acid, also called nonanoic acid, is an organic compound with structural formula CH3(CH2)7CO2H. It is a nine-carbon fatty acid. Nonanoic acid is a colorless oily liquid with an unpleasant, rancid odor. It is nearly insoluble in water, but very soluble in organic solvents. The esters and salts of pelargonic acid are called pelargonates or nonanoates.
Omega oxidation (ω-oxidation) is a process of fatty acid metabolism in some species of animals. It is an alternative pathway to beta oxidation that, instead of involving the β carbon, involves the oxidation of the ω carbon. The process is normally a minor catabolic pathway for medium-chain fatty acids, but becomes more important when β oxidation is defective.
Mead acid is an omega-9 fatty acid, first characterized by James F. Mead. As with some other omega-9 polyunsaturated fatty acids, animals can make Mead acid de novo. Its elevated presence in the blood is an indication of essential fatty acid deficiency. Mead acid is found in large quantities in cartilage.
Long-chain alcohol oxidase is one of two enzyme classes that oxidize long-chain or fatty alcohols to aldehydes. It has been found in certain Candida yeast, where it participates in omega oxidation of fatty acids to produce acyl-CoA for energy or industrial use, as well as in other fungi, plants, and bacteria.
Nervonic acid is a fatty acid. It is a monounsaturated analog of lignoceric acid (24:0). It is also known as selacholeic acid and cis-15-tetracosenoic acid. Its name derives from the Latin word nervus, meaning nerve or sinew.
Omega hydroxy acids are a class of naturally occurring straight-chain aliphatic organic acids n carbon atoms long with a carboxyl group at position 1, and a hydroxyl at terminal position n where n > 3. They are a subclass of hydroxycarboxylic acids. The C16 and C18 omega hydroxy acids 16-hydroxy palmitic acid and 18-hydroxy stearic acid are key monomers of cutin in the plant cuticle. The polymer cutin is formed by interesterification of omega hydroxy acids and derivatives of them that are substituted in mid-chain, such as 10,16-dihydroxy palmitic acid. Only the epidermal cells of plants synthesize cutin.
Dodecanedioic acid (DDDA) is a dicarboxylic acid with the formula (CH2)10(CO2H)2. A white solid, the compound finds a variety of applications ranging from polymers to materials. The unbranched compound is the most commonly encountered C12 dicarboxylic acid.
Short chain ω-phenylalkanoic acids have long been known to occur in natural products. Phenylacetic, 3-phenylpropanoic and 3-phenylpropenoic (cinnamic) acids are found in propolis, mammalian exocrine secretions or plant fragrances. During a systematic study of the lipids from seeds of the plant Araceae, the presence of 13-phenyltridecanoic acid as a major component was discovered. Other similar compounds but with 11 and 15 carbon chain lengths and saturated or unsaturated were shown to be also present but in lower amounts. At the same time, the even carbon chain ω-phenylalkanoic acids of C10 up to C16 were discovered in halophilic bacteria.
Cytochrome P450 omega hydroxylases, also termed cytochrome P450 ω-hydroxylases, CYP450 omega hydroxylases, CYP450 ω-hydroxylases, CYP omega hydroxylase, CYP ω-hydroxylases, fatty acid omega hydroxylases, cytochrome P450 monooxygenases, and fatty acid monooxygenases, are a set of cytochrome P450-containing enzymes that catalyze the addition of a hydroxyl residue to a fatty acid substrate. The CYP omega hydroxylases are often referred to as monoxygenases; however, the monooxygenases are CYP450 enzymes that add a hydroxyl group to a wide range of xenobiotic and naturally occurring endobiotic substrates, most of which are not fatty acids. The CYP450 omega hydroxylases are accordingly better viewed as a subset of monooxygenases that have the ability to hydroxylate fatty acids. While once regarded as functioning mainly in the catabolism of dietary fatty acids, the omega oxygenases are now considered critical in the production or break-down of fatty acid-derived mediators which are made by cells and act within their cells of origin as autocrine signaling agents or on nearby cells as paracrine signaling agents to regulate various functions such as blood pressure control and inflammation.