Difference between revisions of "Gallein"

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3',4',5',6'-tetrahydroxyfluoran; pyrogallolphthalein; CI 45445; mordant violet 25
 
3',4',5',6'-tetrahydroxyfluoran; pyrogallolphthalein; CI 45445; mordant violet 25
  
== Other Properties ==
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== Risks ==
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* Inhalation, ingestion or skin absorption may be harmful. 
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* Sigma Aldrich: [https://www.sigmaaldrich.com/US/en/product/sigma/g1137 SDS]
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==Physical and Chemical Properties==
  
 
Insoluble in cold water, benzene, chloroform.  Slightly soluble in hot water, ether.  Soluble in alkalis, alcohol, acetone.   
 
Insoluble in cold water, benzene, chloroform.  Slightly soluble in hot water, ether.  Soluble in alkalis, alcohol, acetone.   
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== Hazards and Safety ==
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==Resources and Citations==
 
 
Inhalation, ingestion or skin absorption may be harmful. 
 
 
 
Sigma Chemical: [http://hazard.com/msds/f2/bwq/bwqjd.html MSDS]
 
 
 
== Authority ==
 
  
 
* ''The Merck Index'', Martha Windholz (ed.), Merck Research Labs, Rahway NJ, 10th edition, 1983  Comment: entry 4362
 
* ''The Merck Index'', Martha Windholz (ed.), Merck Research Labs, Rahway NJ, 10th edition, 1983  Comment: entry 4362

Latest revision as of 11:22, 25 July 2022

Description

Brownish-red crystals used as a red dye. Gallein was first prepared by Baeyer in 1871 by mixing Pyrogallic acid with Phthalic anhydride. Gallein was used as a dye in the late 19th century but was soon replaced by aniline colors. It produces a bluish-red color with Alumina or iron mordants and a dark violet with lead and tin mordants. Gallein is also used as an acid-base indicator and as a detection reagent for phosphates.

Synonyms and Related Terms

3',4',5',6'-tetrahydroxyfluoran; pyrogallolphthalein; CI 45445; mordant violet 25

Risks

  • Inhalation, ingestion or skin absorption may be harmful.
  • Sigma Aldrich: SDS

Physical and Chemical Properties

Insoluble in cold water, benzene, chloroform. Slightly soluble in hot water, ether. Soluble in alkalis, alcohol, acetone.

As an indicator, brownish-yellow below pH=3.8; red above pH 6.6

Composition C20H12O7
CAS 2103-64-2
Molecular Weight mol. wt. = 364.31

Resources and Citations

  • The Merck Index, Martha Windholz (ed.), Merck Research Labs, Rahway NJ, 10th edition, 1983 Comment: entry 4362
  • F. Crace-Calvert, Dyeing and Calico Printing, Palmer & Howe, London, 1876