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Pyrocatechol
Pyrocatechol
IUPAC name Pyrocatechol
Other names catechol
benzene-1,2-diol
2-hydroxyphenol
α-hydroxyphenol
o-benzenediol
o-hydroxyphenol
1,2-dihydroxybenzene
pyrocatechin
Identifiers
CAS number [120-80-9]
RTECS number UX1050000
SMILES Oc1c(O)cccc1
Properties
Molecular formula C6H6O2
Molar mass 110. IUPAC Nomenclature is a system of naming Chemical compounds and of describing the science of Chemistry in general CAS registry numbers are unique numerical identifiers for Chemical compounds Polymers biological sequences mixtures and Alloys They are also referred to Registry of Toxic Effects of Chemical Substances ( RTECS) is a Database of Toxicity information compiled from the open scientific literature without reference A chemical formula is a way of expressing information about the Atoms that constitute a particular Chemical compound, and how the relationship between those atoms changes Molar mass, symbol M, is the Mass of one mole of a substance ( Chemical element or Chemical compound) 1 g/mol
Appearance white solid
Density 1. The density of a material is defined as its Mass per unit Volume: \rho = \frac{m}{V} Different materials usually have different 344 g/cm³, solid
Melting point

105 °C, 378 K, 221 °F
Boiling point

245. The melting point of a solid is the temperature range at which it changes state from solid to Liquid. The boiling point of a liquid is the temperature at which the Vapor pressure of the liquid equals the environmental pressure surrounding the liquid 5 °C, 519 K, 474 °F
Solubility in water 43 g/100 mL
Hazards
EU classification Harmful (Xn)
NFPA 704
1
2
0
 
R-phrases R21/22, R36/38
S-phrases (S2), S22, S26, S37
Flash point 127 °C
Related compounds
Related benzenediols Resorcinol
Hydroquinone
Related compounds 1,2-benzoquinone
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)
Infobox disclaimer and references

Pyrocatechol, more commonly known as catechol, is a benzenediol, with the formula C6H4(OH)2. Solubility is the characteristic Physical property referring to the ability of a given substance the Solute, to dissolve in a Solvent. Water is a common Chemical substance that is essential for the survival of all known forms of Life. Council Directive 67/548/EEC of 27 June 1967 on the approximation of laws regulations and administrative provisions relating to the classification packaging and labelling Symbolism The four divisions are typically color-coded with blue indicating level of Health Hazard, red indicating R-phrases (short for Risk Phrases) are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous R-phrases (short for Risk Phrases) are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous R-phrases (short for Risk Phrases) are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. The flash point of a flammable liquid is the lowest Temperature at which it can form an ignitable mixture in air Benzenediols or dihydroxybenzenes are Aromatic Chemical compounds and Polyphenols in which two Hydroxyl groups are substituted onto a Resorcinol (or resorcin) is a Chemical compound from the dihydroxy Phenols it is the 13- Isomer of Benzenediol. Hydroquinone, also benzene-14-diol or quinol, is an Aromatic Organic compound which is a type of phenol, having the Chemical In Chemistry, the standard state of a material is its state at 1 bar (100 Kilopascals exactly Benzenediols or dihydroxybenzenes are Aromatic Chemical compounds and Polyphenols in which two Hydroxyl groups are substituted onto a It is a commonly used building block in organic synthesis. Organic synthesis is a special branch of Chemical synthesis and is concerned with the construction of Organic compounds via Organic reactions Organic

Contents

Isolation and synthesis

Catechol was first isolated in 1839 by H. Year 1839 ( MDCCCXXXIX) was a Common year starting on Tuesday (link will display the full calendar of the Gregorian Calendar (or a Common Reinsch by distilling catechin (the juice of Mimosa catechu (Acacia catechu L. Catechins are polyphenolic Antioxidant Plant Metabolites. They belong to the family of Flavonoids and to be more specific flavan-3-ols Acacia catechu is a deciduous thorny tree which grows up to 15m in height f)); it occurs free in kino and in beechwood tar; its sulfonic acid is present in the urine of horse and humans. Pterocarpus marsupium ( Indian Kino Tree, also known as the Malabar Kino Benga, Bijiayasal Nepal or Venkai) is a species of For the babyfood see Beech-Nut. Beech ( Fagus) is a genus of ten Species of Deciduous Trees in the Sulfonic acid is an unstable Acid with the formula H-S(=O2-OH Urine is a liquid waste product of the body secreted by the Kidneys by a process of filtration from Blood and Excreted through the Urethra.

Catechol can be prepared by fusing 2-phenolsulfonic acid, 2-chlorphenol, 2-bromophenol, or 2,6-phenoldisulfonic acid with potash, or, better, by heating its methyl ether, guaiacol, a constituent of beechwood tar, with hydriodic acid. 2-Chlorophenol or ortho -chlorophenol has a medicinal taste and smell and is a slightly acidic liquid (its Acid dissociation constant is 8 Potash (or carbonate of potash) is an impure form of Potassium carbonate ( K 2 CO3) Guaiacol is a naturally occurring Organic compound with the formula C6H4(OH(OCH3 Hydrogen iodide (HI is a Diatomic molecule. Aqueous solutions of HI are known as hydroiodic acid or hydriodic acid, a Strong acid. Many pyrocatechin derivatives have been suggested for therapeutic applications.

Reactions

Organic chemistry

Like other difunctional benzene derivatives, catechol readily condenses to form heterocyclic compounds. Cyclic esters are formed upon treatment with phosphorus trichloride and phosphorus oxychloride, carbonyl chloride, and sulphuryl chloride:

C6H4(OH)2 + XCl2 → C6H4(O2X) + 2 HCl
where X = CO, SO2, PCl, P(O)Cl. Esters are a class of Chemical compounds and Functional groups Esters consist of an inorganic or organic Acid in which at least Phosphorus trichloride (formula P[[Chlorine Cl]]3 is the most important of the three Phosphorus chlorides. Submit to get this template --> Phosphoryl chloride (commonly called phosphorus oxychloride) is a colourless liquid with the formula 3 Phosgene is the Chemical compound with the formula COCl2 This colorless gas gained infamy as a Chemical weapon during World War I

Catechols produce quinones with the addition of Ceric ammonium nitrate (CAN). "DDQ" redirects here DDQ is also the former callsign of a TV station in Toowoomba Queensland Australia Ceric ammonium nitrate, or in lab jargon "CAN" is the Chemical compound with the formula ( NH4)2Ce(NO36

With metal ions

Catechol is the conjugate acid of a chelating agent used widely in coordination chemistry. The term complex in Chemistry is usually used to describe molecules or ensembles formed by the combination of Ligands and metal Ions. 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, whilst the alkaline solution rapidly changes to a green and finally to a black color on exposure to the air. Iron chloride redirects here For Iron(II chloride see Iron(II chloride. It reduces silver solutions in the cold and alkaline copper on heating. Catechol can also be conjugated to ruthenium. [RuIII(NH3)4(catechol)]+ oxidizes faster than catechol in the presence of oxygen, but controlled potential electrolysis showed that its oxidation involves only one electron (Almeida et al. , 2007).

Occurrence

The catechol skeleton occurs in a variety of natural products such as urushiols, which are the skin-irritating poisons found in plants like poison ivy, and catecholamines, hormones/neurotransmitters, and catechin, which is found in tea. For information on urushiol poisoning see Urushiol-induced contact dermatitis. In the context of Biology, poisons are substances that can cause damage, Illness, or Death to Organisms usually by Hormones (from Greek ὁρμή - "impetus" are chemicals released by cells that affect cells in other parts of the body See Chemical synapse for an introduction to concepts and terminology used in this article Catechins are polyphenolic Antioxidant Plant Metabolites. They belong to the family of Flavonoids and to be more specific flavan-3-ols Tea refers to the cured agricultural product of the leaves leaf buds and internodes of Camellia sinensis, which have been prepared and cured for the market

Small amounts of catechol occur naturally in fruits and vegetables, along with the enzyme polyphenol oxidase. Upon mixing the enzyme with the substrate and exposure to oxygen (as when a potato or apple is cut), the colorless catechol oxidizes to reddish-brown benzoquinone derivatives. The enzyme is inactivated by adding an acid, such as lemon juice, or by refrigeration. Excluding oxygen also prevents the browning reaction. Benzoquinone is said to be antimicrobial, which slows the spoilage of wounded fruits and other plant parts.

Uses

Pyrocatechol was used as a developing agent in black-and-white photographic developers, but except for some special purpose applications, its use is largely historical. In Film developing, photographic developer (or just developer) is a chemical that makes the Latent image on the film or print visible

Nomenclature

Pyrocatechol is the name recommended by the International Union of Pure and Applied Chemistry (IUPAC) in its 1993 Recommendations for the Nomenclature of Organic Chemistry. The International Union of Pure and Applied Chemistry ( IUPAC) (aɪjuːpæk or ay-yoo-pec) is an international Non-governmental organization [1]

References

See also

References

  1. ^ Panico, R. For information on urushiol poisoning see Urushiol-induced contact dermatitis. ; & Powell, W. H. (Eds. ) (1994). A Guide to IUPAC Nomenclature of Organic Compounds 1993. Oxford: Blackwell Science. ISBN 0-632-03488-2.  

External links

This article incorporates text from the Encyclopædia Britannica Eleventh Edition, a publication now in the public domain. The Encyclopædia Britannica Eleventh Edition (1910–1911 is a 29-volume reference work that marked the beginning of the Encyclopædia Britannica The public domain is a range of abstract materials &ndash commonly referred to as Intellectual property &ndash which are not owned or controlled by anyone

Dictionary

pyrocatechol

-noun

  1. (organic chemistry) A dihydric phenol, benzene-1,2-diol, present in some tars.
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