CATECHOL

Catechol is an important phenolic intermediate recognized for its strong reactivity and wide usefulness in fine chemical and industrial synthesis.
Catechol's ortho-dihydroxybenzene structure supports applications in antioxidants, polymer systems, specialty formulations, and the manufacture of numerous functional derivatives.
This combination of structural simplicity and chemical versatility makes catechol a valuable raw material for both large-scale processing and advanced research applications.

CAS Number: 120-80-9
EC Number: 204-427-5
Molecular Formula: C6H6O2
Molecular Weight: 110.11 g/mol

Synonyms: pyrocatechol, catechol, 120-80-9, 1,2-dihydroxybenzene, 1,2-benzenediol, benzene-1,2-diol, pyrocatechin, 2-hydroxyphenol, o-Dihydroxybenzene, o-Hydroxyphenol, o-Benzenediol, o-Dioxybenzene, o-Hydroquinone, Phthalhydroquinone, Pyrocatechine, o-Phenylenediol, Oxyphenic acid, Fouramine PCH, Pelagol Grey C, Durafur developer C, Catechin (phenol), Fourrine 68, Benzene, o-dihydroxy-, Catechol (phenol), o-Diphenol, C.I. Oxidation Base 26, ortho-Hydroxyphenol, Pyrokatechin, Pyrokatechol, Katechol, ortho-Dihydroxybenzene, ortho-Benzenediol, ortho-Dioxybenzene, ortho-Hydroquinone, ortho-Phenylenediol, Pyrocatechinic acid, NCI-C55856, Phthalic alcohol, CI Oxidation Base 26, DTXSID3020257, NSC 1573, C.I. 76500, LF3AJ089DQ, CI 76500, AI3-03995, NSC-1573, DTXCID30257, CHEBI:18135, NSC1573, C.I.-76500, 1,2 dihydroxybenzene, RefChem:918128, 204-427-5, Brenzcatechin, benzenediol, MFCD00002188, Catechol-pyrocatechol, 12385-08-9, CHEMBL280998, 26982-53-6, CAQ, 1,?2-?Benzenediol, Katechol [Czech], Pyrokatechin [Czech], Pyrokatechol [Czech], Benzene-1,2-diol (Pyrocatechol), CAS-120-80-9, SMR000326660, CCRIS 741, HSDB 1436, EINECS 204-427-5, UNII-LF3AJ089DQ, BRN 0471401, Oxyphenate, Kachin, ortho-diphenol, benzene diol, ortho-Quinol, 4oow, alpha-hydroxyphenol, o-dihydroxy-benzene, 1,a2-aBenzenediol, phenol derivative, 2, Guaifenesin Impurity 7, 3fw4, 4k7i, CATECHOL [HSDB], CATECHOL [IARC], Pyrocatechol, >=99%, CATECHOL [VANDF], Lopac-C-9510, PYROCATECHOL [MI], WLN: QR BQ, bmse000385, EC 204-427-5, 1,2-Dihydroxybenzene, XI, 1,2-Benzenediol; Catechol, Lopac0_000280, SCHEMBL18351, MLS002153385, MLS002303022, BIDD:ER0327, Pyrocatechinic acidPyrocatechol, SCHEMBL123027, SCHEMBL127281, SCHEMBL135028, SCHEMBL446264, SCHEMBL600496, orb3027299, SCHEMBL7832581, Pyrocatechol, p.a., 99.0%, SCHEMBL10787139, SCHEMBL22284127, SCHEMBL22284136, SCHEMBL29352716, BDBM26188, Durafur Developer CFouramine PCH, MSK2905, HMS2233A17, HMS3260H22, HMS3373K16, DEA96358, Tox21_202317, Tox21_300153, Tox21_500280, EBC-00523, MSK2905-100A, s6305, SBB040792, STK398651, Pyrocatechol; Guaiacol EP Impurity A, AKOS000119002, MSK2905-1000A, CCG-204375, DB02232, FC19837, LP00280, SDCCGSBI-0050268.P002, Catechol(Discontinued,See C4X-12947), NCGC00015283-01, NCGC00015283-02, NCGC00015283-03, NCGC00015283-04, NCGC00015283-05, NCGC00015283-06, NCGC00015283-07, NCGC00015283-08, NCGC00015283-10, NCGC00091262-01, NCGC00091262-02, NCGC00091262-03, NCGC00253952-01, NCGC00259866-01, NCGC00260965-01, AC-34196, BP-21156, BS-20054, Catechol (Pyrocatechol; Benzene-1,2-diol), DB-003770, Catechol Solution in Acetonitrile, 100ug/mL, EU-0100280, NS00007130, P0317, P0567, ST50214346, T4847, 1,2-Benzenediol-1,2,3,4,5,6-13C6, Catechol Solution in Acetonitrile, 1000ug/mL, EN300-19426, C 9510, C00090, C01785, D91943, 1,2-Dihydroxybenzene, ReagentPlus(R), >=99%, Pyrocatechol, purified by sublimation, >=99.5%, AB-131/40235236, F005090, Q282440, SR-01000075791, SR-01000075791-1, 1,2-Dihydroxybenzene 1000 microg/mL in Dichloromethane, F0001-0332, Pyrocatechol, certified reference material, TraceCERT(R), Z104473810, InChI=1/C6H6O2/c7-5-3-1-2-4-6(5)8/h1-4,7-8, Pyrocatechol, plant cell culture tested, BioReagent, >=99%, powder, 2H-1-Benzopyran-3,5,7-triol, 2-(3,4-dihydroxyphenyl)-3,4-dihydro-,(2R-trans)-, 1,2-Benzenediol, 1,2-Benzènediol, 1,2-Benzoldiol, 1,2-dihydroxybenzene, 120-80-9, 204-427-5, 471401, benzene-1,2-diol, benzenediol, Benzol-1,2-diol, catechol, dihydroxybenzene, hydroxyphenol, Pyrocatechol, Pyrocatéchol, 1,2-Benzene-3,4,5,6-d4-diol-d2, 1,2-benzene<wbr/>diol, 1,2-dihydroxybenzen, 1,2-Dihydroxybenzene-[d4], 100 g, 103963-58-2, 115881-16-8, 16474-89-8, 16474-90-1, 2-Hydroxyphenol, 2-Hydroxyphenol; Pyrocatechol; Catechol; o-Benzenediol; 1,2-Benzenediol, 2-Hydroxyphenoxy radical, 202656-22-2, 204-617-8, 26982-53-6, 37349-32-9, 99%, ARGI1_BOVIN, Benzene, o-dihydroxy-, benzene-1,2,3-triol, C.I. Oxidation Base 26, CAH12_HUMAN, CAH13_MOUSE, CAH14_HUMAN, CAH1_HUMAN, CAH2_HUMAN, CAH3_BOVIN, CAH3_HUMAN, CAH4_HUMAN, CAH5A_HUMAN, CAH5B_HUMAN, CAH6_HUMAN, CAH7_HUMAN, CAH9_HUMAN, CAQ, Carbonic anhydrase 1, Carbonic anhydrase 12, Carbonic anhydrase 13, Carbonic anhydrase 14, Carbonic anhydrase 2, Carbonic anhydrase 3, Carbonic anhydrase 4, Carbonic anhydrase 5A, mitochondrial, Carbonic anhydrase 5B, mitochondrial, Carbonic anhydrase 6, Carbonic anhydrase 7, Carbonic anhydrase 9, Catechol-[13C6], Cayman, CI Oxidation Base 26, Durafur developer C, Fouramine PCH, Glutaminyl-peptide cyclotransferase, Kachin, o-Benzenediol, o-Benzosemiquinone, o-Dihydroxybenzene, o-Dioxybenzene, o-Diphenol, o-Hydroquinone, O-Hydroxyphenol, o-Phenylenediol, ortho-Benzenediol, ortho-Dihydroxybenzene, ortho-Dioxybenzene, ortho-Hydroquinone, ortho-Hydroxyphenol, ortho-Phenylenediol, Oxyphenate, Oxyphenic acid, P4HA1_CHICK, Pelagol Grey C, Phenoxy, 2-hydroxy-, Prolyl 4-hydroxylase subunit α-1, PYG, Pyrocatechin, QPCT_HUMAN, QR BQ, α-hydroxyphenol

Catechol is an organic compound with the molecular formula C6H4(OH)2.
Catechol is the ortho isomer of the three isomeric benzenediols.

Catechol occurs naturally in trace amounts.
Catechol was first discovered by destructive distillation of the plant extract catechin.

About 20,000 tonnes of catechol are now synthetically produced annually as a commodity organic chemical, mainly as a precursor to pesticides, flavors, and fragrances.
Small amounts of catechol occur in fruits and vegetables.

Catechol is a white crystalline solid.
Catechol is used as a developer for photographic films, dyes and an intermediate for antioxidants in rubber and lubricating oils.

Catechol is used in polymerization inhibitors and in pharmaceuticals.
Catechol is a building block in organic synthesis and involved in the preparation of flavors and fragrances.

Catechol is used as a replacement for sandalwood oil, which is prepared from catechol through guaiacol and camphor.
Further, Catechol is a precursor for the preparation of vanillin from guaiacol, which is obtained by methylation reaction with catechol.

Catechol is a benzenediol comprising of a benzene core carrying two hydroxy substituents ortho to each other.
Catechol has a role as a genotoxin, an allelochemical and a plant metabolite.
Catechol is a conjugate acid of a catecholate(1-).

Catechol is defined as a phenolic compound characterized by two adjacent hydroxyl groups, which serves as a strong reducing agent and can coordinate with metals.
Catechol is a white crystalline powder that is soluble in water, ether, and ethanol, and is utilized in the preparation of various phenol derivatives and as an adhesive and antibacterial material.

Catechol is defined as a vital chemical compound synthesized primarily through the hydroxylation of phenol, serving as an important reagent in various industrial applications, including pharmaceuticals, photography, and material science.
Catechol possesses versatile chemical properties, allowing for reversible interactions and incorporation into polymers for uses such as drug carriers and antimicrobial coatings.

Catechol is an aromatic organic compound with the molecular formula C6H6O2, consisting of a benzene ring bearing two adjacent hydroxyl groups.
Catechol is widely used as an intermediate in the manufacture of pharmaceuticals, agrochemicals, flavors, fragrances, dyes, antioxidants, and specialty chemicals.
Catechol's two neighboring hydroxyl groups provide distinctive chemical reactivity, making catechol an important building block in organic synthesis, polymer chemistry, and functional material development.

Catechol is an organic compound with the molecular formula C6H4(OH)2.
Catechol is a crystalline substance with a distinctive phenolic fragrance.

Catechol is an aromatic diol that was originally discovered in 1839 through the dry distillation of catechin by Reinsch.
Today, Catechol is synthesized industrially from phenol.

Catechol has been found in a range of sources, including raw beet sugar, crude wood tar, select species of eucalyptus, onions, and coal.

Catechol and its derivatives can be produced through a variety of techniques, such as dry distillation and other procedures, from substances such as tannin, lignin, wood, and bituminous coal.
Additionally, Catechol can be found in tobacco smoke and exists in the form of sulfuric ester in the urine of humans and horses.

Catechol Derivatives:
Catechol derivatives are found widely in nature.
They often arise by hydroxylation of phenols.

Arthropod cuticle consists of chitin linked by a catechol moiety to protein.
The cuticle may be strengthened by cross-linking (tanning and sclerotization), in particular, in insects, and of course by biomineralization.

The synthetic derivative 4-tert-butylcatechol is used as an antioxidant and polymerization inhibitor.

Nomenclature:
Although rarely encountered, the officially "preferred IUPAC name" (PIN) of catechol is benzene-1,2-diol.
The trivial name pyrocatechol is a retained IUPAC name, according to the 1993 Recommendations for the Nomenclature of Organic Chemistry.

Uses of Catechol:
Catechol is used as a photographic developer, a developer for fur dyes, as an intermediate for antioxidants in rubber and lubricating oils, in polymerization inhibitors, and in pharmaceuticals.
Catechol is used in the photography, rubber, dye, and oil industries as an antioxidant; also used to produce cosmetics and pharmaceuticals.

Catechol is used as a developer for photographic films, dyes and an intermediate for antioxidants in rubber and lubricating oils.
Catechol is used in polymerization inhibitors and in pharmaceuticals.

Catechol is a building block in organic synthesis and involved in the preparation of flavors and fragrances.
Catechol is used as a replacement for sandalwood oil, which is prepared from catechol through guaiacol and camphor.

Further, Catechol is a precursor for the preparation of vanillin from guaiacol, which is obtained by methylation reaction with catechol.
Catechol is used largely in the production of pesticides -Used as a precursor to fine chemicals such as perfumes and pharmaceuticals.

Catechol is used in production of ethylvanillin, a component of chocolate confectioneries.
Catechol is used for replacing sandalwood oil Guaiacol is prepared by methylation of catechol.

Approximately 50% of the synthetic catechol is consumed in the production of pesticides, the remainder being used as a precursor to fine chemicals such as perfumes and pharmaceuticals.
Catechol is a common building block in organic synthesis.

Several industrially significant flavors and fragrances are prepared starting from catechol.
Guaiacol is prepared by methylation of catechol and is then converted to vanillin on a scale of about 10M kg per year (1990).

The related monoethyl ether of catechol, guethol, is converted to ethylvanillin, a component of chocolate confectioneries.
3-trans-Isocamphylcyclohexanol, widely used as a replacement for sandalwood oil, is prepared from catechol via guaiacol and camphor.
Piperonal, a flowery scent, is prepared from the methylene diether of catechol followed by condensation with glyoxal and decarboxylation.

Josef Maria Eder published in 1879 his findings on the use of catechol as a black-and-white photographic developer but, except for some special purpose applications, its use is largely historical.
Catechol is rumored to have been used briefly in Eastman Kodak's HC-110 developer and Anchell supposes it to be a component in Tetenal's Neofin Blau developer.

Catechol is a key component of Tanol from Moersch Photochemie in Germany.
Modern catechol developing was pioneered by noted photographer Sandy King, whose "PyroCat" formulation is popular among modern black-and-white film photographers.
King's work has since inspired further 21st-century development by others such as Jay De Fehr with Hypercat and Obsidian Acqua developers, and others.

Industry Uses:
Intermediate

Consumer Uses:
Intermediate

Key Attributes and Properties of Catechol:
Catechol, also known as pyrocatechol or 1,2-dihydroxybenzene, is an organic compound essentially used as building block.

Catechol is available in two forms:
Flakes (solid form) and Molten (liquid form). 

Catechol offers multiple possibilities of bondings, providing different type of interactions and related properties:
Bi-functional molecule
Strong metal chelating agent
Cross linking agent
Oxygen scavenger
Antioxidant 

Isolation and Synthesis of Catechol:
Catechol was first isolated in 1839 by Edgar Hugo Emil Reinsch (1809–1884) by distilling it from the solid tannic preparation catechin, which is the residuum of catechu, the boiled or concentrated juice of Mimosa catechu (Acacia catechu).
Upon heating catechin above its decomposition point, a substance that Reinsch first named Brenz-Katechusäure (burned catechu acid) sublimated as a white efflorescence.

This was a thermal decomposition product of the flavanols in catechin.
In 1841, both Wackenroder and Zwenger independently rediscovered catechol; in reporting on their findings, Philosophical Magazine coined the name pyrocatechin.

By 1852, Erdmann realized that catechol was benzene with two oxygen atoms added to it; in 1867, August Kekulé realized that catechol was a diol of benzene, so by 1868, catechol was listed as pyrocatechol.
In 1879, the Journal of the Chemical Society recommended that catechol be called "catechol", and in the following year, Catechol was listed as such.

Catechol has since been shown to occur in free form naturally in kino and in beechwood tar.
Catechol's sulfonic acid has been detected in the urine of horses and humans.

Catechol is produced industrially by the hydroxylation of phenol using hydrogen peroxide.

C6H5OH + H2O2 → C6H4(OH)2 + H2O

Catechol can be produced by reaction of salicylaldehyde with base and hydrogen peroxide (Dakin oxidation) as well as the hydrolysis of 2-substituted phenols, especially 2-chlorophenol, with hot aqueous solutions containing alkali metal hydroxides.
Catechol's methyl ether derivative, guaiacol, converts to catechol via hydrolysis of the CH3−O bond as promoted by hydroiodic acid (HI).

Production Methods of Catechol:
Catechol may be obtained by the fusion of o-phenolsulfonic acid with alkali, by heating chorophenol with a solution of sodium hydroxide at 200°C in an autoclave, or by cleavage of the methyl ether group of guaiacol (obtained from beechwood tar) with hydriodic acid.

In the past, Catechol was primarily produced through the process of low-temperature carbonization of coal.
However, this technique is presently used only on rare cases.

Production of Catechol by Hydrolysis of 2-Chlorophenol:
In industrial settings, the production of catechol can be accomplished via the hydrolysis of 2-chlorophenol using a solution of barium hydroxide and sodium hydroxide.
The recovery of barium, which is transformed into hydroxide from carbonate and subsequently recycled into the process, contributes to the complexity of the method.
In response, alternative techniques that employ solely caustic alkali have been devised.

For instance, the reaction of 1 mole of 2-chlorophenol with 2.3 moles of a sodium hydroxide solution that ranges from 4-8% is carried out at 190°C for a duration of 3 hours within a copper autoclave, in the presence of copper(II) sulfate or copper(I) oxide.
The selectivity for catechol is 81–86%, while the conversion of 2-chlorophenol ranges from 96–99%.

The resulting mixture is then neutralized using sulfuric acid, and the crude catechol formed is subsequently extracted.
The solvent is recovered, and catechol is purified through distillation.
This method of production was employed for industrial catechol production until 1973.

Production of Catechol by Hydroxylation of Phenol:
The production of catechol is currently carried out by the direct hydroxylation of phenol with peroxides, which also produces hydroquinone.
Three plants employing this method are currently operational worldwide, with each plant utilizing a distinct peroxide or catalyst.

Due to the exothermic nature of the reaction and the tendency of benzenediols to be more readily oxidized than phenol, the reaction is performed with a significant excess of phenol.

A plant in France, operated by Rhone-Poulenc, reacts phenol with 70% hydrogen peroxide (molar ratio 20:1) in the presence of phosphoric acid and catalytic amounts of perchloric acid at 90°C.
This results in the production of catechol and hydroquinone in a ratio of approximately 3:2.

The reaction proceeds electrophilically, and phosphoric acid is employed as a masking reagent to prevent side reactions caused by trace amounts of metallic ions, such as the formation of resorcinol by a radical reaction that results in a lower yield.
Following the reaction, phosphoric and perchloric acids are removed by washing with water, and the reaction mixture is simultaneously extracted by diisopropyl ether, distilled, and continuously separated.

Brichima SpA (now Enichem) in Italy employs heavy metal compounds, such as small quantities of ferrocene and/or cobalt salts, as catalyst and reacts phenol with 60% aqueous hydrogen peroxide at 40°C.
Catechol and hydroquinone are produced in the ratio of 1.5–4.1 through a free-radical chain mechanism that proceeds rapidly.

In Japan, Ube Industries produces catechol with hydroquinone by hydroxylation of phenol with ketone peroxide (methyl ethyl ketone peroxide) formed in situ from a ketone and hydrogen peroxide in the presence of an acid catalyst.

The process is carried out by adding a trace amount of acid, such as sulfuric or sulfonic acid, a small volume of ketone, and 60% aqueous hydrogen peroxide to phenol at 70°C.
The ketone peroxide that is formed in situ reacts rapidly and electrophilically with phenol, and catechol and hydroquinone are produced in a molar ratio of approximately 3:2 in over 90% yield (based on phenol reacted).

When a solid acid such as clay is used as a catalyst, the molar ratio of catechol and hydroquinone is approximately 1:1.
The use of a small amount of catalyst prevents corrosion, and the reaction mixture can be distilled without removing the catalyst after the reaction.
The added ketone can be recycled to the process by recovering it through distillation.

The separation and purification methods employed in all three processes are fundamentally the same.
The reaction mixture is separated through distillation in various distillation columns.

Water is removed, low-boiling fractions (solvents, ketone, etc.), and unreacted phenol are recovered and recycled, the catechol fraction is made into a flaked product, and hydroquinone is purified by recrystallization of the corresponding fraction from water.

Production of Catechol by Dehydrogenation of 1,2-Cyclohexanediol:
Catechol can be synthesized with a 90% yield by dehydrogenation of 1,2-cyclohexanediol using a Pd/Te catalyst system at a temperature of 300 °C.
Catechol has been reported that catechol is produced as the sole product of this process.

Reactions of Catechol:
Like some other difunctional benzene derivatives, catechol readily condenses to form heterocyclic compounds.

For example, using phosphorus trichloride or phosphorus oxychloride gives the cyclic chlorophosphonite or chlorophosphonate, respectively; sulfuryl chloride gives the sulfate; and phosgene (COCl2) gives the carbonate:
C6H4(OH)2 + XCl2 → C6H4(O2X) + 2 HCl where X = PCl or POCl; SO2; CO

Basic solutions of catechol react with iron(III) to give the red [Fe(C6H4O2)3]3−.
Ferric chloride gives a green coloration with the aqueous solution, while the alkaline solution rapidly changes to a green and finally to a black color on exposure to the air.
Iron-containing dioxygenase enzymes catalyze the cleavage of catechol.

Redox chemistry:

Catechols convert to the semiquinone radical. At pH = 7, this conversion occurs at 100 mV:
C6H4(OH)2 → C6H4(O)(OH) + ½ H2

The semiquinone radical can be reduced to the catecholate dianion, the potential being dependent on pH:
C6H4(O)(OH) + e− → [C6H4O2]2− + H+

Catechol is produced by a reversible two-electron, two-proton reduction of 1,2-benzoquinone (E0 = +795 mV vs SHE; Em (at pH 7) = +380 mV vs SHE).

The redox series catecholate dianion, monoanionic semiquinonate, and benzoquinone are collectively called dioxolenes.
Dioxolenes can function as ligands for metal ions.

Stability and Reactivity of Catechol:

Chemical stability:
Catechol is stable under recommended storage conditions but may gradually darken during storage.

Reactivity:
No hazardous polymerization is expected under normal conditions of use.

Conditions to avoid:
Avoid excessive heat, ignition sources, direct sunlight, dust formation, and contact with incompatible materials.

Incompatible materials:
Avoid strong oxidizing agents, bases, acids, acid chlorides, and acid anhydrides.

Hazardous decomposition products:
Thermal decomposition or combustion may produce carbon monoxide, carbon dioxide, and irritating vapors.

Handling and Storage of Catechol:

Safe handling:
Avoid inhalation of dust and contact with the skin, eyes, and clothing.
Use adequate ventilation and minimize dust generation.

Storage conditions:
Keep the container tightly closed in a cool, dry, and well-ventilated place protected from direct sunlight and incompatible materials.

First Aid Measures of Catechol:

Inhalation:
Move the affected person to fresh air and obtain medical attention.

Skin contact:
Remove contaminated clothing and wash the affected area immediately with plenty of water.

Eye contact:
Rinse immediately with plenty of water, including under the eyelids, for at least 15 minutes and obtain medical attention.

Ingestion:
Do not induce vomiting.
Rinse the mouth and obtain immediate medical attention.

Firefighting Measures of Catechol:

Suitable extinguishing media:
Use water spray, carbon dioxide, dry chemical, or alcohol-resistant foam.

Protective equipment:
Firefighters should wear full protective equipment and self-contained breathing apparatus.

Fire hazards:
Fine catechol dust dispersed in air may form an ignitable dust mixture.
Combustion may generate carbon monoxide and carbon dioxide.

Accidental Release Measures of Catechol:

Personal precautions:
Ensure adequate ventilation, avoid dust formation, keep unnecessary personnel away, and use appropriate personal protective equipment.

Cleanup methods:
Carefully sweep or collect spilled material into suitable closed containers while minimizing airborne dust.

Environmental precautions:
Prevent release into drains, surface water, and sewer systems.

Exposure Controls/Personal Protection of Catechol:

Engineering controls:
Provide adequate general or local ventilation and ensure that eyewash stations and safety showers are readily accessible.

Eye protection:
Wear suitable safety glasses or chemical protective goggles.

Hand protection:
Wear appropriate chemical-resistant protective gloves.

Body protection:
Use suitable protective clothing to prevent skin exposure.

Respiratory protection:
Use appropriate respiratory protection when exposure limits may be exceeded or ventilation is insufficient.

Identifiers of Catechol:
Name: benzene-1,2-diol
CAS Number: 120-80-9
ECHA EINECS - REACH Pre-Reg: 204-427-5
FDA UNII: LF3AJ089DQ
Nikkaji Web: J2.921A
Beilstein Number: 0471401
MDL: MFCD00055728
CoE Number: 680
XlogP3: 0.90 (est)
Molecular Weight: 110.11222000
Formula: C6 H6 O2

Product Number: P0567
Purity / Analysis Method: >99.0%(GC)
Molecular Formula / Molecular Weight: C6H6O2 = 110.11
Physical State (20 deg.C): Solid
Storage Temperature: Room Temperature (Recommended in a cool and dark place, <15°C)
Store Under Inert Gas: Store under inert gas
Condition to Avoid: Light Sensitive,Air Sensitive
CAS RN: 120-80-9
Reaxys Registry Number: 471401
PubChem Substance ID: 87574739
SDBS (AIST Spectral DB): 555
Merck Index (14): 7999
MDL Number: MFCD00002188

Product Name: Catechol
[qr];c.i. 76500
CAS: 120-80-9
MF: C6H6O2
MW: 110.11
EINECS: 204-427-5

CAS Number: 120-80-9
3D model (JSmol): Interactive image
Beilstein Reference: 471401
ChEBI: CHEBI:18135
ChEMBL: ChEMBL280998
ChemSpider: 13837760
DrugBank: DB02232
ECHA InfoCard: 100.004.025
EC Number: 204-427-5
Gmelin Reference: 2936
KEGG: C00090
PubChem CID: 289
RTECS number: UX1050000
UNII: LF3AJ089DQ
CompTox Dashboard (EPA): DTXSID3020257
InChI: InChI=1S/C6H6O2/c7-5-3-1-2-4-6(5)8/h1-4,7-8H
Key: YCIMNLLNPGFGHC-UHFFFAOYSA-N
SMILES: Oc1c(O)cccc1

CAS: 120-80-9
IUPAC Name: benzene-1,2-diol
Molecular Formula: C6H6O2
InChI Key: YCIMNLLNPGFGHC-UHFFFAOYSA-N
SMILES: OC1=CC=CC=C1O
Molecular Weight (g/mol): 110.11

Properties of Catechol:
Chemical Formula: C6H6O2
Molar Mass: 110.112 g·mol−1
Appearance: white to brown feathery crystals
Odor: faint, phenolic odor
Density: 1.344 g/cm3, solid
Melting Point: 105 °C (221 °F; 378 K)
Boiling Point: 245.5 °C (473.9 °F; 518.6 K) (sublimes)
Solubility in Water: 312 g/L at 20 °C
Solubility: very soluble in pyridine
Solubility: soluble in chloroform, benzene, CCl4, ether, ethyl acetate
log P: 0.88
Vapor Pressure: 20 Pa (20 °C)
Acidity (pKa): 9.45, 12.8
Magnetic Susceptibility (χ): −6.876×10−5 cm3/mol
Refractive Index (nD): 1.604
Dipole Moment: 2.62±0.03 D

Melting Point: 100-103 °C (lit.)
Boiling Point: 245 °C (lit.)
Density: 1,371 g/cm3
Vapor Density: 3.8 (vs air)
Vapor Pressure: 1 mm Hg (75 °C)
Refractive Index: 1.6120 (estimate)
Fp: 279 °F
Storage Temperature: Store below +30°C.
Solubility: 430g/l
pKa: 9.85(at 20℃)
Form: Crystalline Flakes
Color: white to faintly beige
PH: 6 (100g/l, H2O, 20℃)
Explosive Limit: 1.97%(V)
Biological Source: synthetic (organic)
Water Solubility: 430 g/L (20 ºC)
Sensitive: Air & Light Sensitive
Merck: 14,7999
BRN: 471401
Henry's Law Constant: 8.2×103 mol/(m3Pa) at 25℃, Duchowicz et al. (2020)
Exposure Limits: TLV-TWA 5 ppm (～22 mg/m3) (ACGIH). .
Stability: Stable. Substances to be avoided include acid chlorides, acid anhydrides, bases, oxidizing agents, nitric acid. Light sensitive; may discolour on exposure to air. Combustible.
Cosmetics Ingredients Functions: HAIR DYEING
InChI: 1S/C6H6O2/c7-5-3-1-2-4-6(5)8/h1-4,7-8H
InChIKey: YCIMNLLNPGFGHC-UHFFFAOYSA-N
SMILES: Oc1ccccc1O
LogP: 0.93
CAS DataBase Reference: 120-80-9(CAS DataBase Reference)
NIST Chemistry Reference: 1,2-Benzenediol(120-80-9)
IARC: 2B (Vol. 15, Sup 7, 71) 1999
EPA Substance Registry System: Catechol (120-80-9)

Molecular Weight: 110.11 g/mol
XLogP3: 0.9
Hydrogen Bond Donor Count: 2
Hydrogen Bond Acceptor Count: 2
Rotatable Bond Count: 0
Exact Mass: 110.036779430 Da
Monoisotopic Mass: 110.036779430 Da
Topological Polar Surface Area: 40.5 Ų
Heavy Atom Count: 8
Formal Charge: 0
Complexity: 62.9
Isotope Atom Count: 0
Defined Atom Stereocenter Count: 0
Undefined Atom Stereocenter Count: 0
Defined Bond Stereocenter Count: 0
Undefined Bond Stereocenter Count: 0
Covalently-Bonded Unit Count: 1
Compound Is Canonicalized: Yes

Appearance: white to tan powder (est)
Assay: 97.00 to 100.00
Food Chemicals Codex Listed: No
Melting Point: 103.00 to 105.00 °C. @ 760.00 mm Hg
Boiling Point: 244.00 to 246.00 °C. @ 760.00 mm Hg
Vapor Pressure: 1.000000 mmHg @ 75.00 °C.
Vapor Density: 3.8 (Air = 1)
Flash Point: 279.00 °F. TCC (137.22 °C.)
logP (o/w): 0.880

Melting Point: 105 °C
Boiling Point: 246 °C
Solubility in Water: Soluble
Degree of Solubility in Water: 430 g/l 20 °C
Solubility (soluble in): Alcohol, Benzene, Ether, Chloroform

Specifications of Catechol:
Appearance: White to Light yellow to Light orange powder to crystal
Purity (GC): min. 99.0 %
Appearance (Color): White to cream to grey-brown to brown
Comment: May darken on storage
Melting Point (clear melt): 103-108?C
Form: Crystalline powder or flakes
Identification (FTIR): Conforms
Assay (GC): ≥98.5%

Structure of Catechol:
Crystal Structure: monoclinic

Thermochemistry of Catechol:
Std enthalpy of formation (ΔfH⦵298): −354.1 kJ·mol−1
Enthalpy of fusion (ΔfH⦵fus): 22.8 kJ·mol−1 (at melting point)

Related compounds of Catechol:
1,2-benzoquinone

Related benzenediols:
Resorcinol
Hydroquinone

Names of Catechol:

Preferred IUPAC name:
Benzene-1,2-diol

Other names:
Pyrocatechol
1,2-Benzenediol
2-Hydroxyphenol
1,2-Dihydroxybenzene
o-Benzenediol
o-Dihydroxybenzene