124-04-9 Usage
Uses
Used in Plastics and Polymers Industry:
Adipic acid is used as a precursor in the production of 6,6 nylon, making it a key component in the synthesis of this widely used polymer. It is also used in the solid-state polymerization of nylon analogs.
Used in Chemical Industry:
Adipic acid is utilized in the production of resins, plasticizers, lubricants, polyurethanes, and other chemical products.
Used in Food Industry:
Adipic acid is used as an acidulant and flavoring agent in powdered drinks, beverages, gelatin desserts, lozenges, canned vegetables, and as a leavening acidulant in baking powder. It can also be used as a buffering agent to maintain acidities within a range of pH 2.5–3.0 and occasionally in edible oils to prevent rancidity.
Occurrence:
Adipic acid has been reported as a minor constituent in butter and found in other fats as a product of oxidative rancidity. It also occurs naturally in beet juice, pork fat, guava fruit (Psidium guajava L.), papaya (Carica papaya L.), and raspberry (Rubus idaeus L.).
Production Methods
Adipic acid is prepared by nitric acid oxidation of cyclohexanol or
cyclohexanone or a mixture of the two compounds. Recently,
oxidation of cyclohexene with 30% aqueous hydrogen peroxide
under organic solvent- and halide-free conditions has been
proposed as an environmentally friendly alternative for obtaining
colorless crystalline adipic acid.
Production Methods
Adipic acid can be manufactured using several methods, but the traditional and main route of preparation is by the two-step oxidation of cyclohexane (C6H12). In the first step, cyclohexane is oxidized to cyclohexanone and cyclohexanol with oxygen or air. This occurs at a temperature of approximately 150°C in the presence of cobalt or manganese catalysts. The second oxidation is done with nitric acid and air using copper or vanadium catalysts. In this step, the ring structure is opened and adipic acid and nitrous oxide are formed. Other feedstocks such as benzene and phenol may be use to synthesize adipic acid. Adipic acid production used to be a large emitter of nitrous oxide, a greenhouse gas, but these have been controlled in recent years using pollution abatement technology.
Preparation
Adipic acid is produced from a mixture of cyclohexanol and cyclohexanone called "KA oil", the abbreviation of "ketone-alcohol oil." The KA oil is oxidized with nitric acid to give adipic acid, via a multistep pathway. Early in the reaction the cyclohexanol is converted to the ketone, releasing nitrous acid: HOC6H11 + HNO3 → OC6H10 + HNO2 + H2O Among its many reactions, the cyclohexanone is nitrosated, setting the stage for the scission of the C- C bond: HNO2 + HNO3 → NO+NO3- + H2O OC6H10 + NO+→ OC6H9-2 - NO + H+ Side products of the method include glutaric and succinic acids. Related processes start from cyclohexanol, which is obtained from the hydrogenation of phenol.
Reactions
Adipic acid is a dibasic acid (can be deprotonated twice). Its pKa's are 4.41 and 5.41. With the carboxylate groups separated by four methylene groups, adipic acid is suited for intramolecular condensation reactions. Upon treatment with barium hydroxide at elevated temperatures, it undergoes ketonization to give cyclopentanone.
Biotechnological Production
Adipic acid is industrially produced by chemical synthesis. However, there
are new efforts to develop an adipic acid production process using biorenewable
sources. A direct biosynthesis route has not yet been reported. The possible
precursors Z,Z-muconic acid and glucaric acid can be produced biotechnologically
by fermentation. Z,Z-muconic acid can be made from benzoate with concentrations
up to 130 mM with a yield of close to 100 % (mol/mol) by Pseudomonas putida
KT2440-JD1 grown on glucose. Alternatively, it can be produced by engineered
E. coli directly from glucose at up to 260 mM with a yield of 0.2 mol Z,Zmuconic
acid per mole glucose .
The production of the second possible precursor, glucaric acid, by engineered
E. coli growing on glucose has been reported. However, the product titers were
low (e.g. 4.8 and 12 mM. To overcome the problem of low product
concentrations, an alternative synthetic pathway has been suggested but not yet
demonstrated .
In a hydrogenation process, Z,Z-muconic acid and glucaric acid could be
converted chemically into adipic acid. Therefore, bimetallic nanoparticles or
platinum on activated carbon as catalysts have been studied . In particular,
nanoparticles of Ru10Pt2 anchored within pores of mesoporous silica showed high
selectivity and conversion rates, greater than 0.90 mol adipic acid per mole Z,Zmuconicacid. With platinum on activated carbon, conversion rates of
0.97 mol.mol-1 of Z,Z-muconic acid into adipic acid have been shown.
Another possibility would be the production of adipic acid from glucose via the
a–aminoadipate pathway ]. Finally, the production of adipic acid from longchain
carbon substrates has been suggested. The conversion of fatty acids into
dicarboxylic acids by engineered yeast strains has been reported.
Air & Water Reactions
Dust may form explosive mixture with air [USCG, 1999]. Insoluble in water.
Reactivity Profile
Adipic acid is a carboxylic acid. Carboxylic acids donate hydrogen ions if a base is present to accept them. They react in this way with all bases, both organic (for example, the amines) and inorganic. Their reactions with bases, called "neutralizations", are accompanied by the evolution of substantial amounts of heat. Neutralization between an acid and a base produces water plus a salt. Carboxylic acids with six or fewer carbon atoms are freely or moderately soluble in water; those with more than six carbons are slightly soluble in water. Soluble carboxylic acid dissociate to an extent in water to yield hydrogen ions. The pH of solutions of carboxylic acids is therefore less than 7.0. Many insoluble carboxylic acids react rapidly with aqueous solutions containing a chemical base and dissolve as the neutralization generates a soluble salt. Carboxylic acids in aqueous solution and liquid or molten carboxylic acids can react with active metals to form gaseous hydrogen and a metal salt. Such reactions occur in principle for solid carboxylic acids as well, but are slow if the solid acid remains dry. Even "insoluble" carboxylic acids may absorb enough water from the air and dissolve sufficiently in Adipic acid to corrode or dissolve iron, steel, and aluminum parts and containers. Carboxylic acids, like other acids, react with cyanide salts to generate gaseous hydrogen cyanide. The reaction is slower for dry, solid carboxylic acids. Insoluble carboxylic acids react with solutions of cyanides to cause the release of gaseous hydrogen cyanide. Flammable and/or toxic gases and heat are generated by the reaction of carboxylic acids with diazo compounds, dithiocarbamates, isocyanates, mercaptans, nitrides, and sulfides. Carboxylic acids, especially in aqueous solution, also react with sulfites, nitrites, thiosulfates (to give H2S and SO3), dithionites (SO2), to generate flammable and/or toxic gases and heat. Their reaction with carbonates and bicarbonates generates a harmless gas (carbon dioxide) but still heat. Like other organic compounds, carboxylic acids can be oxidized by strong oxidizing agents and reduced by strong reducing agents. These reactions generate heat. A wide variety of products is possible. Like other acids, carboxylic acids may initiate polymerization reactions; like other acids, they often catalyze (increase the rate of) chemical reactions. Behavior in Fire: Melts and may decompose to give volatile acidic vapors of valeric acid and other substances.
Health Hazard
Exposures to adipic acid cause pain, redness of the skin and eyes, tearing or lacrimation.
Adipic acid has been reported as a non-toxic chemical. Excessive concentrations of adipic
acid dust are known to cause moderate eye irritation, irritation to the skin, and dermatitis.It may be harmful if swallowed or inhaled. It causes respiratory tract irritation with symptoms
of coughing, sneezing, and blood-tinged mucous.
Flammability and Explosibility
Nonflammable
Pharmaceutical Applications
Adipic acid is used as an acidifying and buffering agent in
intramuscular, intravenous and vaginal formulations. It is also
used in food products as a leavening, pH-controlling, or flavoring
agent.
Adipic acid has been incorporated into controlled-release
formulation matrix tablets to obtain pH-independent release for
both weakly basicand weakly acidic drugs.It has also been
incorporated into the polymeric coating of hydrophilic monolithic
systems to modulate the intragel pH, resulting in zero-order release
of a hydrophilic drug.The disintegration at intestinal pH of the
enteric polymer shellac has been reported to improve when adipic
acid was used as a pore-forming agent without affecting release in
the acidic media.Other controlled-release formulations have
included adipic acid with the intention of obtaining a late-burst
release profile.
Safety Profile
Poison by intraperitoneal route. Moderately toxic by other routes. A severe eye irritant. Combustible when exposed to heat or flame; can react with oxidzing materials. When heated to decomposition it emits acrid smoke and fumes.
Safety
Adipic acid is used in pharmaceutical formulations and food
products. The pure form of adipic acid is toxic by the IP route, and
moderately toxic by other routes. It is a severe eye irritant, and may
cause occupational asthma.
LD50 (mouse, IP): 0.28 g/kg
LD50 (mouse, IV): 0.68 g/kg
LD50 (mouse, oral): 1.9 g/kg
LD50 (rat, IP): 0.28 g/kg
LD50 (rat, oral): >11 g/kg
Synthesis
By oxidation of cyclohexanol with concentrated nitric acid; by catalytic oxidation of cyclohexanone with air.
Potential Exposure
Workers in manufacture of nylon, plasticizers, urethanes, adhesives, and food additives
storage
Adipic acid is normally stable but decomposes above boiling point.
It should be stored in a tightly closed container in a cool, dry place,
and should be kept away from heat, sparks, and open flame.
Shipping
UN3077 Environmentally hazardous substances, solid, n.o.s., Hazard class: 9; Labels: 9-Miscellaneous hazardous material, Technical Name Required
Purification Methods
For use as a volumetric standard, adipic acid is crystallised once from hot water with the addition of a little animal charcoal, dried at 120o for 2hours, then recrystallised from acetone and again dried at 120o for 2hours. Other purification procedures include crystallisation from ethyl acetate and from acetone/petroleum ether, fusion followed by filtration and crystallisation from the melt, and preliminary distillation under vacuum. [Beilstein 2 IV 1956.]
Incompatibilities
Adipic acid is incompatible with strong oxidizing agents as well as
strong bases and reducing agents. Contact with alcohols, glycols,
aldehydes, epoxides, or other polymerizing compounds can result in
violent reactions.
Precautions
Occupational workers should avoid contact of the adipic acid with the eyes, avoid breathing
dust, and keep the container closed. Workers should use adipic acid only with adequate
ventilation. Workers should wash thoroughly after handling adipic acid and keep
away from heat, sparks, and flame. Also, workers should use rubber gloves and laboratory
coats, aprons, or coveralls, and avoid creating a dust cloud when handling, transferring,
and cleaning up.
Regulatory Status
GRAS listed. Included in the FDA Inactive Ingredients Database
(IM, IV, and vaginal preparations). Accepted for use as a food
additive in Europe. Included in an oral pastille formulation
available in the UK. Included in the Canadian List of Acceptable
Non-medicinal Ingredients.
Check Digit Verification of cas no
The CAS Registry Mumber 124-04-9 includes 6 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 3 digits, 1,2 and 4 respectively; the second part has 2 digits, 0 and 4 respectively.
Calculate Digit Verification of CAS Registry Number 124-04:
(5*1)+(4*2)+(3*4)+(2*0)+(1*4)=29
29 % 10 = 9
So 124-04-9 is a valid CAS Registry Number.
InChI:InChI=1/C6H10O4/c7-5(8)3-1-2-4-6(9)10/h1-4H2,(H,7,8)(H,9,10)/p-2
124-04-9Relevant articles and documents
A Green Route to Produce Adipic Acid on TiO2–Fe2O3 Nanocomposites
Ameur, Nawal,Bachir, Redouane,Bedrane, Sumeya,Choukchou-Braham, Abderrahim
, p. 1096 - 1103 (2017)
In this work, we study cyclohexene oxidation by molecular oxygen on doped-TiO2. The improvement of the oxidizing capacity of titanium oxide by doping with iron oxide at different molar ratios is checked. All materials with different molar ratios (Ti/Fe = 9, 4, and 2) are prepared by the sol–gel method and fully characterized by ICP, XRD, SEM, DR/UV–vis, IR, and N2 adsorption/desorption. The results show that iron is successfully incorporated into the titanium matrix but the incorporated amount is limited. In catalytic tests, improved activity is noticed while using TiO2 in the presence of Fe2O3, which is due the improved oxidation. Conversion in the range of 21–42% depending on the presence of iron oxide was obtained with excellent yield of adipic acid (97% selectivity).
Optimization of adiponitrile hydrolysis in subcritical water using an orthogonal array design
Duan, Peigao,Wang, Yuanyuan,Yang, Yan,Dai, Liyi
, p. 241 - 258 (2009)
A study of the hydrolysis of adiponitrile (ADN) was performed in subcritical water to research the dependence on experimental conditions. An L25(56) orthogonal array design (OAD) with six factors at five levels using statistical analysis was employed to optimize the experimental conditions for each product in which the interactions between the variables were temporarily neglected. The six factors were adiponitrile concentration (ADN c, wt%), temperature (T), time (t h), percentage of additives (reactant/additive, wt/wt%), additives (A), and pressure (p, MPa). The effects of these parameters were investigated using the analysis of variance (ANOVA) to determine the relationship between experimental conditions and yield levels of different products. The results showed that (ADN c) and T had a significant influence on the yields of adipamide, adipamic acid, and adipic acid at p0.05. Time was the statistically significant factor for the yield of 5-cyanovalermic acid at p0.05 and (ADN c) was the significant factor for the yield of 5-cyanovaleramide at p0.1. Finally, five supplementary experiments were conducted under optimized conditions predicted by the Taguchi method; the results showed that the yield obtained of each product was no lower than that of the highest in the 25 experiments. Carbon balance was calculated to demonstrate the validity of the experimental technique and the reliability of the results. Based on the experimental results, a possible reaction mechanism was proposed.
A Novel Reaction of Some Enolisable Ketones not involving the Rate-determining Enolisation Step. Kinetics of the Reaction of Ketones with Trichloroisocyanuric Acid in the Presence of Added Chloride Ion in Acid Medium
Radhakrishnamurti, Patapati Subu,Rath, Nabeen Kumar,Panda, Rama Krushna
, p. 517 - 522 (1987)
Kinetics of the reaction between some enolisable ketones (S) and trichloroisocyanuric acid (TCICA) in aqueous acid-acetic acid medium at 35 deg C follow pseudo-zero-order and pseudo-first-order disappearance of 0 in the absence and the presence of added Cl-, respectively.The rate constants for the latter system exhibit a linear dependence each on 0 and +>, and an increasing and limiting dependence on added ->.The results are interpreted in terms of probable mechanisms involving (i) rate-determining enol formation from the conjugate acid of the ketone (SH+) in the absence of added Cl- and (ii) rate-determining interaction of SH+ with the most effective molecular chlorine species produced by the hydrolysis of TCICA (rather than a rate-determining interaction of enol with Cl2) in the presence of added Cl-, prior to the rapid steps of product formation.
One pot oxidative cleavage of cyclohexene to adipic acid using silver tungstate nano-rods in a Br?nsted acidic ionic liquid
Vafaeezadeh, Majid,Mahmoodi Hashemi, Mohammad
, p. 31298 - 31302 (2015)
A green and facile method for oxidation of cyclohexene to adipic acid is introduced using 30% H2O2 as oxidant. The catalytic system comprises small amounts of Ag2WO4 nano-rods and a Br?nsted acidic ionic liquid (1,2-dimethyl-3-dodecylidazolium hydrogensulfate).
PHOTOREACTION OF 2-BENZOYLCYCLOHEXANONES ON A SILICA GEL SURFACE: DEVIATION FROM THEIR SOLUTION PHOTOCHEMISTRY
Hasegawa, Tadashi,Imada, Manabu,Yoshioka, Michikazu
, p. 494 - 498 (1993)
On irradiation on a dry silica gel surface, 2-benzoylcyclohexanones which have the lowest n, ?* state and are devoid of methyl substituents on their cyclohexanone rings, undergo an oxidative cleavage to give adipic acid and substituted benzoic acid along with the Norrish Type II product.Irradiation of 2-chlorocyclohexanone and cyclohexane-1,2-dione on silica gel gives adipic acid.The cyclohexanoyl radical on the surface, which is produced from the α-cleavage of the 2-benzoyl group of the 2-benzoylcyclohexanones or the cleavage of the C-Cl bond of 2-chlorocyclohexanone, is suggested as the precursor of adipic acid; the radical is probably converted into cyclohexane-1,2-dione, which undergoes a secondary photoreaction to give adipic acid on the surface.
Synthesis of AgWCNx Nanocomposites for the One-Step Conversion of Cyclohexene to Adipic Acid and Its Mechanistic Studies
Goyal, Reena,Sameer, Siddharth,Sarkar, Bipul,Bag, Arijit,Singhal, Nikita,Bordoloi, Ankur
, p. 16555 - 16565 (2017)
A novel catalyst composed of silver nanoparticles grafted on WCNx has been prepared by using a facile pH-adjusted method. The material reported in this study presents a non-mineral acid route for the synthesis of the industrially significant monomer adipic acid through the selective oxidation of cyclohexene. Ag has been stabilized in the hydrophobic matrix during the formation of the mesoporous silica material by using aniline as stabilizing agent. A cyclohexene conversion of 92.2 % with 96.2 % selectivity for adipic acid was observed with the AgWCNx-2 catalyst, therefore, the AgWCNx catalyst was found to be efficient for the direct conversion to adipic acid with respect to their monometallic counterparts. The energy profile diagrams for each reaction path by using the AgWCNx catalyst were studied along with their monometallic counterparts by using the Gaussian 09 package. The reported material can avoid the use of harmful phase-transfer catalysts (PTC) and/or chlorinated additives, which are two among other benefits of the reported work.
Oxidation of cyclohexane to adipic acid using Fe-porphyrin as a biomimetic catalyst
Yuan, Ying,Ji, Hongbing,Chen, Yixia,Han, Yong,Song, Xufeng,She, Yuanbin,Zhong, Rugang
, p. 418 - 420 (2004)
A one-pot oxidation from cyclohexane to adipic acid has been developed, catalyzed by Fe-porphyrin in the presence of molecular oxygen without any additives. When the reaction temperature is 140°C, oxygen pressure is 2.5 MPa, concentration of catalyst is 1.33 × 10-5 mol %, and reaction time is 8 h, the yield of adipic acid reaches 21.4%. A turnover number of about 24582 is thus far the highest one among those reported for the direct oxidation from cyclohexane to adipic acid.
The primary stages of polyoxomolybdate catalyzed cyclohexanone oxidation by hydrogen peroxide as investigated by in situ NMR. Substrate activation and evolution of the working catalyst
Amitouche, Dahbia,Haouas, Mohamed,Mazari, Tassadit,Mouanni, Sihem,Canioni, Romain,Rabia, Chérifa,Cadot, Emmanuel,Marchal-Roch, Catherine
, p. 104 - 116 (2018)
The catalytic process of cyclohexanone oxidation by hydrogen peroxide was investigated using in situ NMR spectroscopy in real working conditions. The behavior of the Keggin heteropolyacid H3PMo12O40, used as a model catalyst, was explored before and after adding the oxidant agent. This study revealed the evolution pathways to different reduced states of H3PMo12O40 and its reversible transformation into peroxomolybdate complexes. These latter were identified as the active species for the adipic acid formation, while the acid function of the catalyst was found important for the substrate activation via ketonic-enolic tautomerism. The oxidative mechanism of the cyclohexanone was described through three successive steps to produce adipic acid.
Liquid-phase catalytic oxidation of C6-C7 cycloolefins into carboxylic acids in a pseudohomogeneous system
Alimardanov, Kh. M.,Sadygov,Garibov,Abbasov,Abdullaeva, M. Ya.,Dzhafarova
, p. 236 - 242 (2011)
Liquid-phase oxidation of cyclohexene, methylcyclohexene isomers, and norbornene with a 30% solution of hydrogen peroxide in a pseudohomogeneous system involving highly dispersed compounds of Group-VIb and -VIIIb metals supported by nanosize carbon particles was studied.
Oxidation of cyclohexene into adipic acid in aqueous dispersions of mesoporous oxides with built-in catalytical sites
Bohstroem, Zebastian,Rico-Lattes, Isabelle,Holmberg, Krister
, p. 1861 - 1869 (2010)
Reactant incompatibility is a common problem in organic chemistry. This study investigates the use of concentrated aqueous dispersions of mesoporous oxides to overcome incompatibility. Oxidation of cyclohexene into adipic acid using aqueous hydrogen peroxide as oxidant has been performed in a range of ordered and disordered mesoporous materials. The different mesoporous oxides have been characterised with diffraction techniques (XRD and SAXS), electron microscopy (TEM and SEM) and nitrogen adsorption isotherms (BET and BJH methods). The catalyst used in the reaction was either soluble sodium tungstate added to a reaction system based on mesoporous silica, alumina or a silica/alumina mixture; or a catalytic oxide, tungsten oxide or titania, present in the framework of the mesoporous material. Tungsten oxide, either used as the sole oxide material or as a mixed oxide with silica turned out to be very efficient and gave almost quantitative yield of adipic acid. A major advantage with having the catalyst chemically incorporated in the walls of the porous material is that it can be easily reused. The results from recycling experiments show that the catalytic activity is retained.
