Adipic acid
From Wikipedia, the free encyclopedia
| Adipic acid | |
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| IUPAC name | hexanedioic acid |
| Other names | butane-1,4-dicarboxylic acid |
| Identifiers | |
| CAS number | [124-04-9] |
| SMILES | OC(=O)CCCCC(=O)O |
| Properties | |
| Molecular formula | C6H10O4 |
| Molar mass | 146.14 g/mol |
| Appearance | White crystals |
| Density | 1.36 g/cm³ |
| Melting point |
152 °C (425 K) |
| Boiling point |
337 °C (610 K) |
| Solubility in water | slightly soluble |
| Hazards | |
| Main hazards | flammable |
| R-phrases | R: R36 |
| Flash point | 232 °C |
| Related compounds | |
| Related dicarboxylic acids | glutaric acid pimelic acid |
| Related compounds | hexanoic acid |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
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Adipic acid (IUPAC systematic name: hexanedioic acid) is a dicarboxylic acid. It is a white crystalline powder. Due to its long aliphatic chain, it is not very soluble in water.
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[edit] Preparation
Historically, adipic acid was prepared from various fats using oxidation. Current commercial adipic acid is produced from cyclohexane by two oxidation steps.
- Cyclohexane + O2 → cyclohexanol and cyclohexanone+byproducts
- cyclohexanol/cyclohexanone + nitric acid + air → adipic acid + nitrous oxide
(The mixture of cyclohexanol and cyclohexanone produced from cyclohexane is commercially called "KA oil", the abbreviation of "Ketone-Alcohol oil".)
Other patented processes include those using phenol as feedstock. For example, phenol can be oxidized to KA oil, which is further processed give adipic acid.[1]
Utilizing principles of green chemistry, a new method of synthesis has been developed, which involves oxidizing cyclohexene with hydrogen peroxide via a tungsten catalyst and a phase transfer catalyst to produce adipic acid.[2] The waste product is water.
[edit] Uses
By far the main use of adipic acid is as monomer for the production of nylon by a polycondensation reaction with hexamethylene diamine forming 6,6-nylon. Other uses include:
- Monomer for production of Polyurethane
- reactant to form plasticizers and lubricant components
- Food Ingredient as a flavorant and gelling aid.E-number E355.
- 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
[edit] References
- ^ U.S. Patent 7,250,537
- ^ Sato, K.; Aoki, M.; Noyori, R. (1998). "A "Green" route to adipic acid: direct oxidation of cyclohexenes with 30 percent hydrogen peroxide". Science 281 (5383): 1646-7. doi:.
