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See also: C6H4(OH)2, first prepared in 1839 by H
.
Reinsch on distilling catechin (the juice of Mimosa See also: catechu); occurs See also: free in kino and in beechwood See also: tar; its sulphonic acid is See also: present in the urine of the See also: horse and See also: man
.
It results in the alkaline See also: fusion of many resins, and may be prepared by fusing ortho-phenolsulphonic acid, o-chlorphenol, o-bromphenol, and o-phenoldisulphonic acid with potash, or, better, by See also: heating its methyl See also: ether, guaiacol, C6H4(OH) (OCH3), a constituent of beechwood tar, with hydriodic acid
.
See also: Pyrocatechin crystallizes in See also: white rhombic prisms, which melt at 104° and
See also: boil at 245°; it is readily soluble in See also: water, See also: alcohol and ether
.
Ferric chloride gives a See also: green coloration with the aqueous solution, whilst the alkaline solution rapidly changes to a green and finally to a black colour on exposure to the air
.
It reduces See also: silver solutions in the cold and alkaline copper on heating
.
Guaiacol may be obtained directly from beechwood tar, from pyrocatechin by methylation with potash and potassium methyl sulphate at 18o°, or from anisol by nitration, reduction of the ortho-nitroanisol to amino-anisol, which is then diazotized and
boiled with water
.
It melts at 28° and boils at 25o°
.
It is employed
in See also: medicine as an expectorant
.
The dimethyl ether or veratrol i phosphate (PbCl)Pb4(PO4)3, sometimes occurring in sufficient is also used in medicine
.
Many other pyrocatechin derivatives have abundance to be See also: mined as an ore of See also: lead. been suggested for therapeutic application
.
Guaiacol carbonate
is known as duotal, the phosphate as phosphatol, the phosphite as guaiaco-phosphal; phosphotal is a mixture of the phosphites of See also: creosote phenols
.
The valerianic ester of guaiacol is known as geosote, the benzoic as benzosol, the salicylic as guaiacolsalol, while the See also: glycerin ether appears as guaiamar
.
Pyrocatechin readily condenses to See also: form heterocyclic compounds; cyclic See also: esters are formed by phosphorus trichloride and oxychloride, carbonyl chloride, sulphuryl chloride, &c.; whilst ortho-phenylenediamine, o-aminophenol, and o-aminothiophenol give See also: phenazine, phenoxazine and thiodiphenylamine
.
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