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EC / List no.: 201-762-9
CAS no.: 87-66-1
Mol. formula: C6H6O3
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.
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.
PMK
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
Methods of Manufacturing
From gallic acid (decarboxylation); from cyclohexanone (alpha chlorination/hydration/dehydrochlorination)
Heating gallic acid with three times its weight of water in an autoclave
Commercially produced by decarboxylation of gallic acid, which is prepared by hydrolysis of tannin.
... Methods for producing Pyrogallic Acid include oxidation of resorcinol with hydrogen peroxide, hydrolysis of 2,6-diamino-4-butylphenol, demethylation of 4-substituted 2,6-dimethoxyphenols, oxidation of 2,6-dimethylphenol, hydrolysis of 2,2,6,6-tetrachlorocyclohexanone, deoximation of 1,2,3-cyclohexanetrion-1,3-dioxime, and dehydrogenation of 1,2,3-trihydroxycyclohexane.
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 , Pyrogallic acid, Pyrogallic Acid .
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.
Chemical name: 1,2,3-Trihydroxybenene
Molecular formula: C6H3(OH) 3
Molecular weight: 126.11
Property: the product is white glossy crystal powder; soluble in water, ethyl alcohol and diethyl ether
Uses: chemical reagent, medical intermediate, fine chemical, food fresh keeping
Uses: Developer in photography.
Making colloidal solutions of metals.
As mordant for wool, staining leather.
Manufacturing various dyes.
Oxygen absorbant in gas analysis
About Pyrogallic Acid
Helpful information
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 formulation or re-packing and at industrial sites.
Consumer Uses
ECHA has no public registered data indicating whether or in which chemical products the substance might be used. ECHA has no public registered data on the routes by which Pyrogallic Acid is most likely to be released to the environment.
Article service life
ECHA has no public registered data on the routes by which Pyrogallic Acid is most likely to be released to the environment. ECHA has no public registered data indicating whether or into which articles the substance might have been processed.
Widespread uses by professional workers
ECHA has no public registered data indicating whether or in which chemical products the substance might be used. ECHA has no public registered data on the types of manufacture using Pyrogallic Acid. ECHA has no public registered data on the routes by which Pyrogallic Acid is most likely to be released to the environment.
Formulation or re-packing
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.
Uses at industrial sites
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.
Manufacture
ECHA has no public registered data on the routes by which Pyrogallic Acid is most likely to be released to the environment.
IUPAC NAMES:
1,2,3-trihydroxybenzene
1,2,3-Trihydroxybenzol
Benzene-1,2,3-triol
benzene-1,2,3-triol
PYROGALLIC ACID
Pyrogallic acid
Pyrogallic Acid
Pyrogallic Acid
Pyrogallic Acid
SYNONYMS:
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'
