Adipic acid
Names | |
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Preferred IUPAC name
Hexanedioic acid | |
Other names
Adipic acid
Butane-1,4-dicarboxylic acid Hexane-1,6-dioic acid 1,4-butanedicarboxylic acid | |
Identifiers | |
3D model (
JSmol ) |
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1209788 | |
ChEBI | |
ChEMBL | |
ChemSpider | |
ECHA InfoCard
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100.004.250 |
EC Number |
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E number | E355 (antioxidants, ...) |
3166 | |
KEGG | |
PubChem CID
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RTECS number
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UNII | |
UN number | 3077 |
CompTox Dashboard (EPA)
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Properties | |
C6H10O4 | |
Molar mass | 146.142 g·mol−1 |
Appearance | White crystals[1] Monoclinic prisms[2] |
Odor | Odorless |
Density | 1.360 g/cm3 |
Melting point | 152.1 °C (305.8 °F; 425.2 K) |
Boiling point | 337.5 °C (639.5 °F; 610.6 K) |
14 g/L (10 °C) 24 g/L (25 °C) 1600 g/L (100 °C) | |
Solubility | Very soluble in methanol, ethanol soluble in acetone, acetic acid slightly soluble in cyclohexane negligible in benzene, petroleum ether |
log P | 0.08 |
Vapor pressure | 0.097 hPa (18.5 °C) = 0.073 mmHg |
Acidity (pKa) | 4.43, 5.41 |
Conjugate base
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Adipate |
Viscosity | 4.54 cP (160 °C) |
Structure | |
Monoclinic | |
Thermochemistry | |
Std enthalpy of (ΔfH⦵298)formation |
−994.3 kJ/mol[3] |
Hazards | |
GHS labelling: | |
Warning | |
H319 | |
P264, P280, P305+P351+P338, P337+P313 | |
NFPA 704 (fire diamond) | |
Flash point | 196 °C (385 °F; 469 K) |
422 °C (792 °F; 695 K) | |
Lethal dose or concentration (LD, LC): | |
LD50 (median dose)
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3600 mg/kg (rat) |
Safety data sheet (SDS) | External MSDS |
Related compounds | |
Related dicarboxylic acids
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glutaric acid pimelic acid |
Related compounds
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hexanediamide
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Adipic acid or hexanedioic acid is the
Preparation and reactivity
Adipic acid is produced by oxidation of a mixture of cyclohexanone and cyclohexanol, which is called KA oil, an abbreviation of ketone-alcohol oil. Nitric acid is the oxidant. The pathway is multistep. Early in the reaction, the cyclohexanol is converted to the ketone, releasing nitrous acid:
- HOCH(CH2)5 + HNO3 → O=C(CH2)5 + HNO2 + H2O
The cyclohexanone is then nitrosated, setting the stage for the scission of the C-C bond:
- HNO2 + HNO3 → [NO+]NO3]− + H2O
- O=C(CH2)5 + NO+ → O=C(CHNO)(CH2)4 + H+
Side products of the method include glutaric and succinic acids. Nitrous oxide is produced in about one to one mole ratio to the adipic acid,[5] as well, via the intermediacy of a nitrolic acid.[4]
Related processes start from cyclohexanol, which is obtained from the hydrogenation of phenol.[4][6]
Alternative methods of production
Several methods have been developed by
- CH2=CH−CH=CH2 + 2 CO + 2 H2O → HO2C(CH2)4CO2H
Another method is oxidative cleavage of cyclohexene using hydrogen peroxide.[7] The waste product is water.
Historically, adipic acid was prepared by oxidation of various fats,[8] thus the name (ultimately from Latin adeps, adipis – "animal fat"; cf. adipose tissue).
Reactions
Adipic acid is a
With the carboxylate groups separated by four
Uses
About 60% of the 2.5 billion kg of adipic acid produced annually is used as monomer for the production of
In medicine
Adipic acid has been incorporated into controlled-release formulation matrix tablets to obtain pH-independent release for both weakly basic and weakly acidic drugs. It has also been incorporated into the polymeric coating of
In foods
Small but significant amounts of adipic acid are used as a food ingredient as a
Safety
Adipic acid, like most carboxylic acids, is a mild skin irritant. It is mildly toxic, with a median lethal dose of 3600 mg/kg for oral ingestion by rats.[4]
Environmental
The production of adipic acid is linked to emissions of
- 2 N2O → 2 N2 + O2
Adipate salts and esters
The anionic (HO2C(CH2)4CO2−) and dianionic (−O2C(CH2)4CO2−) forms of adipic acid are referred to as adipates. An adipate compound is a
Some adipate salts are used as acidity regulators, including:
- Sodium adipate (E number E356)
- Potassium adipate (E357)
Some adipate esters are used as plasticizers, including:
References
- .
- ^ The Merck Index. Royal Society of Chemistry. 2013. Retrieved 2 March 2017.
- ISBN 978-1-4665-7114-3.
- ^ ISBN 3527306730.
- .
- ^ Ellis, B. A. (1925). "Adipic Acid". Organic Syntheses. 5: 9; Collected Volumes, vol. 1, p. 560.
- PMID 9733504.
- .
- ISBN 978-3527306732.
- ^ Thorpe, J. F.; Kon, G. A. R. (1925). "Cyclopentanone". Organic Syntheses. 5: 37; Collected Volumes, vol. 1, p. 192.
- ^ "Adipic Acid". Archived from the original on 2015-05-18. Retrieved 2015-05-09. PCI abstract for adipic acid
- ^ "Polyvinylchloride - an overview | ScienceDirect Topics". www.sciencedirect.com. Retrieved 2023-11-10.
- ^ Roew, Raymond (2009), "Adipic Acid", Handbook of Pharmaceutical Excipients, pp. 11–12
- ^ "Cherry Jell-O Nutrition Facts". Kraft Foods. Archived from the original on 24 September 2019. Retrieved 21 Mar 2012.
- ^ American Chemical Society (9 February 2015). "Molecule of the Week: Adipic Acid".
- ^ US EPA (12 August 2013). "U.S. Greenhouse Gas Inventory Report, Chapter 4. Industrial Processes" (PDF). Retrieved 2013-11-29.
- ISBN 978-94-015-9343-4.
Appendix
- U.S. FDA citations – GRAS (21 CFR 184.1009), Indirect additive (21 CFR 175.300, 21 CFR 175.320, 21 CFR 176.170, 21 CFR 176.180, 21 CFR 177.1200, 21 CFR 177.1390, 21 CFR 177.1500, 21 CFR 177.1630, 21 CFR 177.1680, 21 CFR 177.2420, 21 CFR 177.2600)
- European Union Citations – Decision 1999/217/EC – Flavoing Substance; Directive 95/2/EC, Annex IV – Permitted Food Additive; 2002/72/EC, Annex A – Authorized monomer for Food Contact Plastics
External links
- International Chemical Safety Card 0369
- SIDS Initial Assessment Report for Adipic acid from the Organisation for Economic Co-operation and Development(OECD)
- adipic acid on chemicalland