Orcin

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Structural formula
Structural formula of orcin
General
Surname Orcin
other names
  • 5-methylbenzene-1,3-diol ( IUPAC )
  • 3,5-dihydroxytoluene
  • 5-methylresorcinol
  • Orcinol
Molecular formula C 7 H 8 O 2
Brief description

white to yellowish white powder with a phenolic odor

External identifiers / databases
CAS number
  • 504-15-4
  • 6153-39-5 (monohydrate)
EC number 207-984-2
ECHA InfoCard 100.007.259
PubChem 10436
ChemSpider 13839080
Wikidata Q412476
properties
Molar mass
  • 124.14 g mol −1
  • 142.15 g mol −1 (monohydrate)
Physical state

firmly

Melting point
  • 106-112 ° C
  • 56–58 ° C (monohydrate)
boiling point

290 ° C

pK s value

9.52

solubility

80 g / l (20 ° C)

safety instructions
GHS labeling of hazardous substances
07 - Warning

Caution

H and P phrases H: 302-315-319-335
P: 261-305 + 351 + 338
Toxicological data

> 2000 mg kg −1 ( LD 50 ,  rat ,  oral )

As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Orcin ( 3,5-dihydroxytoluene , 5-methylresorcinol , formerly also called orcinol ) is an aromatic chemical compound , the structure of which consists of a benzene ring with two attached hydroxyl groups  (-OH) and a methyl group  (-CH 3 ) as substituents . It belongs to the group of dihydroxytoluenes , a group of six constitutional isomers . Namely and structurally it is closely related to resorcinol , it is its methyl derivative.

History and occurrence

Orcin was obtained in 1829 by the French chemist Pierre Jean Robiquet from lichens of the genus Rocella by treating an extract from the lichens with alkalis. It is also found in the flowers of mosses such as Ditrichia viscosa and the leaves of tree heather ( Erica arborea ). Orcine is the parent substance of many lichen dyes, such as litmus , orcein, and orseille . Orsellic acid, orcin and penicillic acid are found in cultures of Penicillium fennelliae .

presentation

Orcin arises u. a. with rapid heating of orsellinic that at 176 ° C decarboxylation .

Decarboxylation of orsellic acid to orcin
Orcin, e.g. T. reddish discoloration

properties

Physical Properties

Orcine is a white to yellowish-white powder with a phenol-like odor that slowly turns reddish in color when exposed to air. In the anhydrous form it has a melting point of 106–112 ° C, as a monohydrate one at 56–58 ° C; the boiling point is 290 ° C.

Chemical properties

Chemically it behaves typically like a phenol , for example in alkaline solution it forms a phenolate , which has a significantly higher water solubility. In contrast to resorcinol, it does not form a triphenylmethane dye with phthalic anhydride similar to fluorescein . It also has an antimicrobial effect.

use

It finds its use u. a. in the bial sample . Riboses form furfural under the action of strong mineral acids . The green-blue color is caused by an iron complex being formed. Detection reactions with aldehydes and hexoses have also been described.

literature

Individual evidence

  1. ↑ a b c data sheet 3,5-dihydroxytoluene (PDF) from Merck , accessed on June 28, 2013.
  2. ↑ a b c data sheet 3,5-dihydroxytoluene (orcinol 97%) from Sigma-Aldrich , accessed on June 28, 2013 ( PDF ).
  3. ↑ a b data sheet 3,5-dihydroxytoluene (orcinol monohydrate) from Sigma-Aldrich , accessed on June 28, 2013 ( PDF ).
  4. ↑ Chemical Dictionary Online: orcinol ; Retrieved June 28, 2013.
  5. ↑ Robiquet: "Essai analytique des lichens de l'orseille", in: Annales de Chimie et de Physique , 1829 , 42 , pp. 236-257. (Translation: Attempt to analyze the lichenes which the Orseille provide. In: Polytechnisches Journal . 36, 1830, pp. 153-169. )
  6. ↑ Robiquet: "Essai analytique des lichens de l'orseille", in: Annales scientifique de l'Auvergne , 1830 , pp. 337–341.
  7. ↑ Robiquet: “Nouvelles Observations sur l'Orcine”, in: Annales de Chimie et de Physique , 1835 , 58 , pp. 320-335. (Translation: New observations on orcin, the dye of "Variolaria dealbata". In: Polytechnisches Journal . 57, 1835, pp. 215-223. )
  8. ↑ Robiquet: "New observations on orcin", in: Annalen der Chemie und Pharmacie , 1835 , 15 , pp. 289-300.
  9. ↑ Dumas: "Ueber das Orcin", in: Journal für Praktische Chemie , 1839 , 16  (1), pp. 422-428 ( doi : 10.1002 / prac.183901601100 ).
  10. ↑ V. de Luynes: "Investigations on Orcin", in: Justus Liebigs Annalen der Chemie , 1864 , 130  (1), pp. 31-35 ( doi : 10.1002 / jlac.18641300104 ).
  11. ↑ V. de Luynes: "Investigations on Orcin", in: Justus Liebigs Annalen der Chemie , 1865 , 136  (1), pp. 72-75 ( doi : 10.1002 / jlac.18651360107 ).
  12. ↑ "Ueber das Orcin", in: Journal für Praktische Chemie , 1866 , 98  (1), pp. 111-113 ( doi : 10.1002 / prac.18660980126 ).
  13. ^ RHC Nevile and A. Winther: "Ueber Orcin und some other Dioxytoluole", in: Reports of the German Chemical Society , 1882 , 15  (2), pp. 2976-2995 ( doi : 10.1002 / cber.188201502292 ).
  14. ↑ GW Eijk: "Isolation and identification of orsellinic acid and penicillic acid produced by Penicillium fennelliae Stolk", in: Antonie van Leeuwenhoek , 1969 , 35  (1), pp. 497-504 ( doi : 10.1007 / BF02219167 ).
  15. ↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Physical Constants of Organic Compounds, pp. 3-182.
  16. ^ R. Hegnauer: Chemotaxonomy of Plants , Volume 1: Thallophyten, Bryophyten; Pteridophytes and gymnosperms, Birkhäuser Verlag, Basel 1962, p. 160 ( limited preview in Google book search).
  17. ↑ W. Grütz: “About the detection of aldehydes by color reactions with orcin”, in: Fresenius' Journal of Analytical Chemistry , 1953 , 138  (1), pp. 144-145 ( doi : 10.1007 / BF00460899 ).
  18. ↑ M. Schönenberger, H. Kellner, H. Südhof and H. Haupt: “On the methodology of hexose determination in serum proteins with orcin”, in: Hoppe-Seyler's Zeitschrift für Physiologische Chemie , 1958 , 309  (1), pp. 145–157 ( doi : 10.1515 / bchm2.1958.309.1.145 ).
  19. ↑ Winfried Opitz and Josef Pieper: “Determination of hexoses by the orcin method; Calculation of the total  amount of hexoses ", in: Clinica Chimica Acta , 1964 , 10 (2), pp. 181-187 ( doi : 10.1016 / 0009-8981 (64) 90163-9 ).

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