Everything about Resorcinol totally explained
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Resorcinol (or
resorcin) is a
chemical compound from the dihydroxy
phenols. it's the 1,3-
isomer of
benzenediol. It is also known with a variety of other names, including: m-dihydroxybenzene, 1,3-benzenediol, 1,3-dihydroxybenzene, 3-hydroxyphenol, m-hydroquinone, m-benzenediol, and 3-hydroxycyclohexadien-1-one.
Nomenclature
Resorcinol is the name recommended by the
International Union of Pure and Applied Chemistry (IUPAC) in its
1993 Recommendations for the Nomenclature of Organic Chemistry.
Production
It is obtained on fusing many
resins (
galbanum,
asafoetida, etc.) with
potassium hydroxide, or by the
distillation of
Brazilwood extract. It may be prepared
synthetically by fusing
3-iodophenol,
phenol-3-sulfonic acid or
benzene-1,3-disulfonic acid with
potassium carbonate; by the action of
nitrous acid on
3-aminophenol; or by the action of 10%
hydrochloric acid on
1,3-diaminobenzene . Many
ortho- and
para-compounds of the
aromatic series (for example, the bromophenols, benzene-
para-disulfonic acid) also yield resorcinol on fusion with potassium hydroxide.
Properties
Resorcinol crystallizes from
benzene as colorless needles which are readily soluble in water, alcohol and ether, but insoluble in
chloroform and
carbon disulfide. It reduces
Fehling's solution, and
ammoniacal silver solutions. It doesn't form a precipitate with
lead acetate solution, as the isomeric
pyrocatechol does.
Iron(III) chloride colors its aqueous solution a dark violet, and
bromine water precipitates tribromoresorcin. These properties are what give it its use as a colouring agent for certain
Chromatography experiments.
Sodium amalgam reduces it to dihydroresorcin, which when heated to 150 to 160 °C with concentrated
barium hydroxide solution gives γ-acetylbutyric acid (D. Vorlgnder); when fused with potassium hydroxide, resorcinol yields
phloroglucin, pyrocatechol and
diresorcin. It
condenses with
acids or
acid chlorides, in the presence of dehydrating agents, to oxyketones, for example with
zinc chloride and glacial
acetic acid at 145 °C it yields resacetophenone (HO)
2C
6H
3~CO.CH
3(M. Nencki and N. Sieber, Jour. prak. Chem., 1881, 23, p. 147). With the
anhydrides of dibasic acids it yields
fluoresceins. When heated with
calcium chloride—
ammonia to 200 °C it yields meta-dioxydiphenylamine (A. Seyewitz, Bull. Soc. Chins., 1890, 3, p. 811). With
sodium nitrite it forms a water-soluble blue dye, which is turned red by acids, and is used as an
indicator, under the name of lacmoid (M. C. Traub and C. Hock, Ber., 1884, 17, p. 2615). It condenses readily with
aldehydes, yielding with
formaldehyde, on the addition of catalytic
hydrochloric acid, methylene diresorcin [(HO)C
6H
3(O)]
2•CH
2, whilst with
chloral hydrate, in the presence of
potassium bisulfate, it yields the
lactone of tetra-oxydiphenyl methane carboxylic acid (J. T. Hewitt and F. G. Pope, Jour. C/tern. Soc., 1897, 75, p. 1084). In alcoholic solution it condenses with
sodium acetoacetate to form 13-methylumbelliferone, C~OH
8O
3 (A. Michael, Jour. prak. Chem., 1888, 37, 470).
With concentrated
nitric acid, in the presence of cold concentrated
sulfuric acid, it yields trinitro-resorcin (
styphnic acid), which forms yellow crystals, exploding violently on rapid heating.
Applications
Medical
Used externally it's an
antiseptic and
disinfectant, and is used 5 to 10% in ointments in the treatment of chronic skin diseases such as
psoriasis and
eczema of a sub-acute character. It is present in over-the-counter topical
acne treatments at 2% concentration, and in prescription treatments at higher concentrations. Weak, watery solutions of resorcinol (25 to 35 g/kg) are useful in allaying the itching in
erythematous eczema. A 2% solution used as a spray has been used with marked effect in
hay fever and in
whooping cough. In the latter disease 0.6 mL of the 2% solution has been given internally. It can be included as an anti-
dandruff agent in
shampoo or in
sunscreen cosmetics. It has also been employed in the treatment of
gastric ulcers in doses of 125 to 250 mg in pills, and is said to be
analgesic and
haemostatic in its action. In large doses it's a
poison causing
giddiness,
deafness,
salivation,
sweating and
convulsions. It is also worked up in certain medicated soaps. Monoacetylresorcinol, C
6H
4(OH)(O-COCH
3), is used under the name of
euresol.
Chemical
Resorcinol is also used as a chemical intermediate for the synthesis of pharmaceuticals and other organic compounds. It is used in the production of diazo dyes and plasticizers and as a
UV absorber in resins.
An emerging use of resorcinol is as a template molecule in
supramolecular chemistry. The -OH groups on resorcinol form
hydrogen bonds to target molecules holding them in the proper orientation for a reaction. Many such reactions are able to be carried out in the
solid state thereby reducing or eliminating the use of solvents that may be harmful to the environment. (see
Green chemistry)
Resorcinol is an analytical reagent for the qualitative determinaion of ketoses (
Seliwanoff's test).
Resorcinol is the starting material for
resorcinarene molecules.
Related compounds
Resazurin, C
12H
7NO
4, obtained by the action of nitrous acid on resorcinol, forms small dark red crystals possessing a greenish metallic glance. When dissolved in concentrated sulfuric acid and warmed to 210 °C, the solution on pouring into water yields a precipitate of resorufin, C
12H
7NO
3, an oxyphenoxazone, which is insoluble in water, but is readily soluble in hot concentrated hydrochloric acid, and in solutions of caustic alkalis. The alkaline solutions are of a rose-red color and show a cinnabar-red fluorescence. A tetrabromresorufin is used as a dye-stuff under the name of Fluorescent Resorcin Blue.
Thioresorcinol is obtained by the action of zinc and hydrochloric acid on the chloride of benzene meta-disulfonic acid. It melts at 27 °C and boils at 243 °C. Resorcinol disulfonic acid (HO)
2C
6H
2(HSO3)
2, is a deliquescent mass obtained by the action of sulfuric acid on resorcin . It is easily soluble in water and decomposes when heated to 100 °C.
Further Information
Get more info on 'Resorcinol'.
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