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Pyrogallic Acid is an organic compound with the formula C6H3(OH)3.
Pyrogallic Acid is a white, water-soluble solid although samples are typically brownish because of its sensitivity toward oxygen.
Pyrogallic Acid is one of three isomeric benzenetriols.
CAS Number: 87-66-1
EC Number: 201-762-9
IUPAC Name: Benzene-1,2,3-triol
Chemmical Formula: C6H6O3
Other names: pyrogallol, benzene-1,2,3-triol, 87-66-1, 1,2,3-trihydroxybenzene, pyrogallic acid, 1,2,3-benzenetriol, Fouramine Brown AP, fourrine PG, fourrine 85, Pyro, Piral, C.I. Oxidation Base 32, fouramine base ap, C.I. 76515, 1,2,3-Trihydroxybenzen, Benzene, 1,2,3-trihydroxy-, NSC 5035, UNII-01Y4A2QXY0, 2,3-Dihydroxyphenol, 1,2,3-Trihydroxybenzen [Czech], 1,2,3-TRIHYDROXY-BENZENE, Pyrogallol, ACS reagent, MFCD00002192, 01Y4A2QXY0, CHEMBL307145, CHEBI:16164, 1,2,3-Benzenetriol, homopolymer, Pyrogallol, 99%, NCGC00091507-01, 1, 2, 3-Benzenetriol, DSSTox_CID_5983, DSSTox_RID_77980, DSSTox_GSID_25983, 1,2,3-Trihydroxybenzen (CZECH), CI Oxidation Base 32, Benzene-1,2,3-triol (Pyrogallol), CAS-87-66-1, Pyrogallol [NF], 30813-84-4, PYG, CCRIS 1940, HSDB 794, PYROGALLOL, ACS, EINECS 201-762-9, BRN 0907431, CI 76515, Pyrogallol;, pyrogallyl group, trihydroxybenzene, AI3-00709, Pyrogallol polymer, Pyrogallol solution, Pyrogallol-[d6], 1,3-Benzenetriol, Pyrogallol, 98%, PYROP, 1,3-Trihydroxybenzen, Pyrogallic Acid,(S), 1,3-Trihydroxybenzene, benzene-1,2-3-triol, Benzene,2,3-trihydroxy-, ACMC-1AG9D, WLN: QR BQ CQ, SCHEMBL3532, C.I. Oxidation Base 32, 4-06-00-07327 (Beilstein Handbook Reference), MLS001066376, Pyrogallol, analytical standard, 1,2,3-Trihydroxybenzene, XIV, DTXSID6025983, Pyrogallol, >=98% (HPLC), Pyrogallol, p.a., ACS reagent, NSC5035, ZINC330141, BCP15871, HY-N1579, NSC-5035, Pyrogallol, ACS reagent, >=99%, STR08708, Tox21_111143, Tox21_202373, ANW-38873, BBL011607, BDBM50031472, CP0116, Pyrogallol, Vetec(TM) reagent grade, s3885, SBB060422, STL163335, AKOS000120163, AM10660, CCG-266100, CS-W019928, MCULE-6282052463, 1,2,3-Benzenetriol (ACD/Name 4.0), NCGC00091507-02, NCGC00091507-03, NCGC00259922-01, Pyrogallol, purum, >=98.0% (HPLC), AC-11384, BP-12538, DA-40956, GMN, K567, Pyrogallol, SAJ first grade, >=98.0%, SMR000471842, Pyrogallol, JIS special grade, >=99.0%, FT-0606230, P0570, ST51046603, 6328-EP2292597A1, 6328-EP2305685A1, 6328-EP2305825A1, C01108, AB-131/40221933, Q388692, W-104009, 2,3-Dihydroxyphenol; Benzene-1,2,3-triol; NSC 5035, F0001-2163, 1216684-97-7, 1,2,3-Trihydroxybenzen, 1,2,3-trihydroxy-benzen, 1,2,3-trihydroxybenzen(czech), 1,2,3-trihydroxybenzene(pyrogallol), 2,3-Dihydroxyphenol, Benzene, 1,2,3-trihydroxy-, benzene-1,2,3-triol, C.I. Oxidation Base 32, c.i.oxidationbase32, cioxidationbase32, Fouramine base ap, Fouramine Brown AP, fouraminebrownap, Fourrine 85, Fourrine PG, fourrine85, fourrinepg, Piral, pyrogallic, PYROGALLOL TRIMETHYL ETHER, PYROGALLIC ACID TRIMETHYL ETHER, PYROGALLOL (1,2,3-TRIHYDROXYBENZENE), Pyrogallol (Pyrogallic Acid), PYROGALLOL extrapure AR, 1,2,3-Trihydroxybenzene, Pyrogallolum, Pyrogallol, Crystal, Reagent, Pyrogallol ,99%, 1,2,3-Benzenetriol, 1,2,3-Trihydroxybenzene, C.I. 76515, Pyrogallol, ISOCINCHOMERONIC ACID(RG), PYROGALLOL, >=98% (HPLC), 1,2,3-Trihydroxybenzene Pyrogallol Pyrogallic acid 1,2,3-Benzenetriol, Coke gallic acid, Pyrogallo, Pyrogallol, 99.8%, Phloroglucinol Impurity A, Focus of gallic acid, Pyrogallol, 99% 500GR, (1S,3R)-1-(2-Nitrophenyl)ethylcarboxyaminocyclopentane-1,3-dicarboxylicacid, NPEC-caged-(1S,3R)-ACPD, Pyrogallol solution,1,2,3-Trihydroxybenzene, Pyrogallol, synthesis grade, Spiro[3H-2,1-benzoxanthiole-3,9′-xanthene]3′,4′,5′,6′-tetrol-1,1-dioxide, Phloroglucinol Impurity 1, Benzene-1,2,3-triol 98+%, 1-(2,3-Dichlorophenyl)piperazine dimer, Pyrogallol 87-66-1 1,2,3-Trihydroxybenzene, 1,2,3-Trihydroxybenzene 87-66-1 Pyrogallol, Pyrogallol 87-66-1, PYROGALLOL, REAGENT (ACS)PYROGALLOL, REAGENT (ACS)PYROGALLOL, REAGENT (ACS), Alkaline pyrogallic acid test solution(ChP), AMPK&gamma, Pyrogallic, AR, Pyrogallic, >99.0%(GC), 1/2/3 (5' -AMP-Activated Protein Kinase Subunit gamma-1, AMPK gamma1, AMPK Subunit gamma-1, AMPKg, PRKAG1, AMPKy1, AMPK-y1, 5'
Production, occurrence, reactions
Pyrogallic Acid is produced in the manner it was first prepared by Scheele (1786): heating gallic acid.
Presently gallic acid is obtained from tannin.
Because tannin is expensive, many alternative routes have been devised.
An alternate preparation involves treating para-chlorophenoldisulfonic acid with potassium hydroxide, a variant on the time-honored route to phenols from sulfonic acids.
The aquatic plant Myriophyllum spicatum produces pyrogallic acid.
When in alkaline solution, it absorbs oxygen from the air, turning brown from a colourless solution.
Pyrogallic Acid can be used in this way to calculate the amount of oxygen in air, notably via the use of the Orsat apparatus.
Uses:
One can find its uses in hair dyeing, dyeing of suturing materials and for oxygen absorption in gas analysis.
Pyrogallic Acid also has antiseptic properties.
Pyrogallic Acid was also used as a developing agent in black-and-white developers, but its use is largely historical except for special purpose applications.
Hydroquinone is more commonly used today.
Pyrogallic Acid is also used in isolation of inert gases from a mixture of gases, which requires absorption of oxygen from the mixture.
Use in photography
Though a popular photographic developing agent in the 19th and early 20th centuries, Pyrogallic Acid largely fell out of favor around the 1920s, although it was still used by a few notable photographers including Edward Weston.
In those days it had a reputation for erratic and unreliable behavior, due possibly to its propensity for oxidation.
Pyrogallic Acid experienced a revival starting in the 1980s due largely to the efforts of experimenters Gordon Hutchings and John Wimberley.
Hutchings spent over a decade working on Pyrogallic Acid formulas, eventually producing one he named PMK for its main ingredients: Pyrogallic Acid , Metol, and Kodalk (the trade name of Kodak for sodium metaborate).
This formulation resolved the consistency issues, and Hutchings found that an interaction between the greenish stain given to film by pyro developers and the color sensitivity of modern variable-contrast photographic papers gave the effect of an extreme compensating developer.
From 1969 to 1977, Wimberley experimented with the Pyrogallic Acid developing agent.
He published his formula for WD2D in 1977 in Petersen's Photographic. PMK and other modern pyro formulations are now used by many black-and-white photographers.
The Film Developing Cookbook has examples.
510-pyro
Another developer mainly based on Pyrogallic Acid was formulated by Jay DeFehr.
The 510-pyro, is a concentrate that uses Triethanolamine as Alkali, and Pyrogallic Acid and phenidone as combined developers.
This developer has both staining and tanning properties and negatives developed with it are immune to the callier effect.
Pyrogallic Acid can be used for small and large negative formats.
The Darkroom Cookbook (Alternative Process Photography) has examples.
Use and Manufacturing
Developer in photography; making colloidal soln of metals; as mordant for wool, staining leather; process engraving; manufacture of various dyes; dyeing furs, hair; analytical chemistry reagent for antimony and bismuth; active reducer for gold, silver and mercury salts; for absorption of oxygen in gas analysis
Dyestuffs intermediate; mordant (wool/leather dyeing); analytical reagent (antimony, bismuth, gas analysis)
Manufacture of polymers
For more Uses (Complete) data for Pyrogallic acid (6 total), please visit the HSDB record page.
Industry Uses
Processing aids, not otherwise listed
Consumer Uses
Personal care products
General Manufacturing Information
Industry Processing Sectors
All other basic organic chemical manufacturing
Chemical Properties:
white crystalline solid
White or nearly white needle- or leaf-shaped crystals or crystalline powder.
Pyrogallic Acid is practically odorless.
Uses:
Pyrogallic Acid is used in the manufacture of various dyes; in dyeing furs, hairs, and feathers; for staining leather; in engraving;as a developer in photography; and as an analytical reagent..
Pyrogallic Acid possesses importance as a spectrophotometric reagent in the determination of niobium and tantalum.
The absorptions of niobium and tantalum complexes are usually measured at 340 and 335 nm, respectively.
The niobium complex is formed in slightly acidic medium, and the tantalum complex in strongly acidic medium (4 N HC1).
The absorption spectra are pH-dependen.
Uses:
Complexing agent; reducing agent; alkaline solution indicator for gaseous oxygen.
Definition
ChEBI: A benzenetriol carrying hydroxy groups at positions 1, 2 and 3.
Production Methods
Pyrogallic Acid is prepared by heating dried gallic acid at about 200°C with the loss of carbon dioxide or by the chlorination of cyclohexanol to tetrachlorocyclohexanone, followed by hydrolysis.
General Description
Odorless white to gray solid. Sinks and mixes with water.
Air & Water Reactions
Turns gray on exposure to light or air.
Water soluble.
Reactivity Profile
Pyrogallic Acid is a strong reducing agent.
Reacts with alkalis, NH3, antipyrine, camphor, phenol, iron and lead salts, iodine, lime water, menthol and KMnO4.
Pyrogallic Acid , also called pyrogallic acid, or 1,2,3-trihydroxybenzene, an organic compound belonging to the phenol family, used as a photographic film developer and in the preparation of other chemicals.
Pyrogallic Acid was first obtained in 1786 from gallic acid, obtainable from galls and barks of various trees.
Pyrogallic Acid is converted to Pyrogallic Acid by heating with water under pressure.
Pyrogallic Acid is the oldest photographic developer, its rapid deposition of silver from silver salts having first been noted in 1832.
kAlkaline solutions of Pyrogallic Acid absorb oxygen efficiently and are used in determining the oxygen content of gas mixtures.
Description
Tiny, white, light-sensitive crystals that tend to float with air movement.
Pyrogallic acid, or pyro, is used as a developer in photographic solutions.
Pyrogallic Acid reduces the salts of Gold, Silver, Mercury, and Platinum to their metallic state.
This characteristic was first noted in 1832 and soon after it was applied to photograph development. Pyrogallic acid is also used in the manufacture of dyes.
Synonyms and Related Terms
Pyrogallic Acid ; pyro; 1,2,3-trihydroxybenzene; 1,2,3-benzenetriol; Fouramine brown AP; Fourrin; CI 76515; Oxidation base 32; Piral
These corrosion data are mainly based on results of general corrosion laboratory tests, carried out with pure chemicals and water solutions nearly saturated with air (the corrosion rate can be quite different if the solution is free from oxygen).
All concentrations are given in weight-% and the solvent is water if nothing else is shown.
The corrosion data apply to annealed materials with normal microstructure and clean surfaces, throughout.
Pyrogallic Acid, also known as 1,2,3-Trihydroxybenzene, 1,2,3-Benzenetriol
At room temperature, it is a white shiny crystalline powder that tastes bitter and slowly turns dark gray when exposed to the air.
Slow heating can sublimate. soluble in water.
The aqueous solution gradually turns dark when exposed to air, and the caustic soda aqueous solution discolors quickly.
Soluble in ethanol and ether, slightly soluble in benzene, chloroform, carbon disulfide.
Uses: Developer in photography.
Making colloidal solutions of metals.
As mordant for wool, staining leather.
Manufacturing various dyes.
Oxygen absorbant in gas analysis
Pyrogallic Acid is registered under the REACH Regulation and is manufactured in and / or imported to the European Economic Area, at ≥ 10 to < 100 tonnes per annum.
Pyrogallic Acid is used in the following products: pH regulators and water treatment products.
Release to the environment of Pyrogallic Acid can occur from industrial use: formulation of mixtures.
Pyrogallic Acid is used in the following products: coating products, inks and toners and pH regulators and water treatment products.
Pyrogallic Acid is used for the manufacture of: chemicals.
Release to the environment of Pyrogallic Acid can occur from industrial use: as an intermediate step in further manufacturing of another substance (use of intermediates), in the production of articles and as processing aid.
