Resorcinol is a dihydroxy benzene
Benzene is an organic chemical compound. It is composed of 6 carbon atoms in a ring, with 1 hydrogen atom attached to each carbon atom, with the molecular formula C6H6....

. It is the 1,3-isomer
In chemistry, isomers are compounds with the same molecular formula but different structural formulas. Isomers do not necessarily share similar properties, unless they also have the same functional groups. There are many different classes of isomers, like stereoisomers, enantiomers, geometrical...

 of benzenediol
Benzenediols or dihydroxybenzenes are organic chemical compounds in which two hydroxyl groups are substituted onto a benzene ring. These aromatic compounds are classed as phenols, and more specifically as polyphenols...

 with the formula
Chemical formula
A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....



Benzene-1,3-diol is the name recommended by the International Union of Pure and Applied Chemistry
International Union of Pure and Applied Chemistry
The International Union of Pure and Applied Chemistry is an international federation of National Adhering Organizations that represents chemists in individual countries. It is a member of the International Council for Science . The international headquarters of IUPAC is located in Zürich,...

 (IUPAC) in its 1993 Recommendations for the Nomenclature of Organic Chemistry.


It is produced when any of a large number of resin
Resin in the most specific use of the term is a hydrocarbon secretion of many plants, particularly coniferous trees. Resins are valued for their chemical properties and associated uses, such as the production of varnishes, adhesives, and food glazing agents; as an important source of raw materials...

s (e.g., galbanum
Galbanum is an aromatic gum resin, the product of certain umbelliferous Persian plant species, chiefly Ferula gummosa and Ferula rubricaulis. Galbanum-yielding plants grow plentifully on the slopes of the mountain ranges of northern Iran...

, asafoetida
Asafoetida , alternative spelling asafetida, is the dried latex exuded from the living underground rhizome or tap root of several species of Ferula, which is a perennial herb...

, etc.) are melted with potassium hydroxide
Potassium hydroxide
Potassium hydroxide is an inorganic compound with the formula KOH, commonly called caustic potash.Along with sodium hydroxide , this colorless solid is a prototypical strong base. It has many industrial and niche applications. Most applications exploit its reactivity toward acids and its corrosive...

, or by the distillation
Distillation is a method of separating mixtures based on differences in volatilities of components in a boiling liquid mixture. Distillation is a unit operation, or a physical separation process, and not a chemical reaction....

 of Brazilwood
Caesalpinia echinata is a species of Brazilian timber tree in the pea family, Fabaceae. Common names include Brazilwood, Pau-Brasil, Pau de Pernambuco and Ibirapitanga . This plant has a dense, orange-red heartwood that takes a high shine, and it is the premier wood used for making bows for...

 extract. It may be prepared synthetically
Organic synthesis
Organic synthesis is a special branch of chemical synthesis and is concerned with the construction of organic compounds via organic reactions. Organic molecules can often contain a higher level of complexity compared to purely inorganic compounds, so the synthesis of organic compounds has...

 by melting 3-iodophenol, phenol-3-sulfonic acid, or benzene-1,3-disulfonic acid with potassium carbonate
Potassium carbonate
Potassium carbonate is a white salt, soluble in water , which forms a strongly alkaline solution. It can be made as the product of potassium hydroxide's absorbent reaction with carbon dioxide. It is deliquescent, often appearing a damp or wet solid...

; by the action of nitrous acid
Nitrous acid
Nitrous acid is a weak and monobasic acid known only in solution and in the form of nitrite salts.Nitrous acid is used to make diazides from amines; this occurs by nucleophilic attack of the amine onto the nitrite, reprotonation by the surrounding solvent, and double-elimination of water...

 on 3-aminophenol
3-Aminophenol is a compound with formula C6H4. It is an aromatic amine and aromatic alcohol. It is an isomer of 2-aminophenol and 4-aminophenol....

; or by the action of 10% hydrochloric acid
Hydrochloric acid
Hydrochloric acid is a solution of hydrogen chloride in water, that is a highly corrosive, strong mineral acid with many industrial uses. It is found naturally in gastric acid....

 on 1,3-diaminobenzene
m-Phenylenediamine, also called 1,3-diaminobenzene, is an organic compound with the formula C6H42. It is an isomer of o-phenylenediamine and p-phenylenediamine. It is a colourless solid.-Production:...

. 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.


Resorcinol crystallizes from benzene
Benzene is an organic chemical compound. It is composed of 6 carbon atoms in a ring, with 1 hydrogen atom attached to each carbon atom, with the molecular formula C6H6....

 as colorless needles that are readily soluble in water, alcohol, and ether, but insoluble in chloroform
Chloroform is an organic compound with formula CHCl3. It is one of the four chloromethanes. The colorless, sweet-smelling, dense liquid is a trihalomethane, and is considered somewhat hazardous...

 and carbon disulfide
Carbon disulfide
Carbon disulfide is a colorless volatile liquid with the formula CS2. The compound is used frequently as a building block in organic chemistry as well as an industrial and chemical non-polar solvent...

. It reduces Fehling's solution
Fehling's solution
Fehling's solution is a chemical test used to differentiate between water-soluble aldehyde and ketone functional groups, and as a test for monosaccharides. The test was developed by German chemist Hermann von Fehling in 1849.-Laboratory preparation:...

 and ammoniacal silver solutions
Tollens' reagent
Tollens' reagent is a chemical reagent most commonly used to determine whether a known carbonyl-containing compound is an aldehyde or a ketone. It is usually ammoniacal silver nitrate, but can also be other mixtures, as long as aqueous diamminesilver complex is present...

. It does not form a precipitate with lead acetate
Lead acetate
Lead acetate can refer to:* Lead acetate , Pb4* Lead acetate , Pb2...

solution, as the isomeric pyrocatechol
Catechol, also known as pyrocatechol or 1,2-dihydroxybenzene, is an organic compound with the molecular formula C6H42. It is the ortho isomer of the three isomeric benzenediols. This colourless compound occurs naturally in trace amounts...

 does. Iron(III) chloride
Iron(III) chloride
Iron chloride, also called ferric chloride, is an industrial scale commodity chemical compound, with the formula FeCl3. The colour of iron chloride crystals depends on the viewing angle: by reflected light the crystals appear dark green, but by transmitted light they appear purple-red...

 colors its aqueous solution a dark-violet, and bromine
Bromine ") is a chemical element with the symbol Br, an atomic number of 35, and an atomic mass of 79.904. It is in the halogen element group. The element was isolated independently by two chemists, Carl Jacob Löwig and Antoine Jerome Balard, in 1825–1826...

 water precipitates tribromoresorcin. These properties are what give it its use as a colouring agent for certain chromatography
Chromatography is the collective term for a set of laboratory techniques for the separation of mixtures....

 experiments. Sodium amalgam
Sodium amalgam
Sodium amalgam, commonly denoted Na, is an alloy of mercury and sodium. The term amalgam is used for alloys, intermetallic compounds, and solutions involving mercury as a major component. Sodium amalgam is often used in reactions as strong reducing agents with better handling properties compared...

 reduces it to dihydroresorcin, which when heated to 150 to 160 °C with concentrated barium hydroxide
Barium hydroxide
Barium hydroxide is the chemical compound with the formula Ba2. Also known as baryta, it is one of the principal compounds of barium. The white granular monohydrate is the usual commercial form.-Preparation:...

 solution gives γ-acetylbutyric acid (D. Vorlgnder); when fused with potassium hydroxide, resorcinol yields phloroglucin, pyrocatechol, and diresorcin. It condenses
Condensation reaction
A condensation reaction is a chemical reaction in which two molecules or moieties combine to form one single molecule, together with the loss of a small molecule. When this small molecule is water, it is known as a dehydration reaction; other possible small molecules lost are hydrogen chloride,...

 with acid
An acid is a substance which reacts with a base. Commonly, acids can be identified as tasting sour, reacting with metals such as calcium, and bases like sodium carbonate. Aqueous acids have a pH of less than 7, where an acid of lower pH is typically stronger, and turn blue litmus paper red...

s or acid chlorides, in the presence of dehydrating agents, to oxyketones, e.g.
with zinc chloride
Zinc chloride
Zinc chloride is the name of chemical compound with the formula ZnCl2 and its hydrates. Zinc chlorides, of which nine crystalline forms are known, are colorless or white, and are highly soluble in water. ZnCl2 itself is hygroscopic and even deliquescent. Samples should therefore be protected from...

 and glacial acetic acid
Acetic acid
Acetic acid is an organic compound with the chemical formula CH3CO2H . It is a colourless liquid that when undiluted is also called glacial acetic acid. Acetic acid is the main component of vinegar , and has a distinctive sour taste and pungent smell...

 at 145 °C it yields resacetophenone (HO)2C6H3~CO.CH3. With the anhydrides of dibasic acids, it yields fluorescein
Fluorescein is a synthetic organic compound available as a dark orange/red powder soluble in water and alcohol. It is widely used as a fluorescent tracer for many applications....

s. When heated with calcium chloride
Calcium chloride
Calcium chloride, CaCl2, is a salt of calcium and chlorine. It behaves as a typical ionic halide, and is solid at room temperature. Common applications include brine for refrigeration plants, ice and dust control on roads, and desiccation...

Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...

 to 200 °C it yields meta-dioxydiphenylamine. With sodium nitrite
Sodium nitrite
Sodium nitrite is the inorganic compound with the chemical formula NaNO2. It is a white to slight yellowish crystalline powder that is very soluble in water and is hygroscopic...

 it forms a water-soluble blue dye, which is turned red by acids, and is used as an indicator
PH indicator
A pH indicator is a halochromic chemical compound that is added in small amounts to a solution so that the pH of the solution can be determined visually. Hence a pH indicator is a chemical detector for hydronium ions or hydrogen ions in the Arrhenius model. Normally, the indicator causes the...

, under the name of lacmoid. It condenses readily with aldehyde
An aldehyde is an organic compound containing a formyl group. This functional group, with the structure R-CHO, consists of a carbonyl center bonded to hydrogen and an R group....

s, yielding with formaldehyde
Formaldehyde is an organic compound with the formula CH2O. It is the simplest aldehyde, hence its systematic name methanal.Formaldehyde is a colorless gas with a characteristic pungent odor. It is an important precursor to many other chemical compounds, especially for polymers...

, on the addition of catalytic hydrochloric acid
Hydrochloric acid
Hydrochloric acid is a solution of hydrogen chloride in water, that is a highly corrosive, strong mineral acid with many industrial uses. It is found naturally in gastric acid....

, methylene diresorcin [(HO)C6H3(O)]2•CH2. Reaction with chloral hydrate
Chloral hydrate
Chloral hydrate is a sedative and hypnotic drug as well as a chemical reagent and precursor. The name chloral hydrate indicates that it is formed from chloral by the addition of one molecule of water. Its chemical formula is C2H3Cl3O2....

 in the presence of potassium bisulfate yields the lactone
In chemistry, a lactone is a cyclic ester which can be seen as the condensation product of an alcohol group -OH and a carboxylic acid group -COOH in the same molecule...

 of tetra-oxydiphenyl methane
carboxylic acid. In alcoholic solution it condenses with sodium acetoacetate to form 4-methylumbelliferone.

In addition to electrophilic aromatic addition, resorcinol (and other poly-ols)undergo nucleophilic substitution via the enone form. With concentrated nitric acid
Nitric acid
Nitric acid , also known as aqua fortis and spirit of nitre, is a highly corrosive and toxic strong acid.Colorless when pure, older samples tend to acquire a yellow cast due to the accumulation of oxides of nitrogen. If the solution contains more than 86% nitric acid, it is referred to as fuming...

, in the presence of cold concentrated sulfuric acid
Sulfuric acid
Sulfuric acid is a strong mineral acid with the molecular formula . Its historical name is oil of vitriol. Pure sulfuric acid is a highly corrosive, colorless, viscous liquid. The salts of sulfuric acid are called sulfates...

, it yields trinitro-resorcin (styphnic acid
Styphnic acid
Styphnic acid, or 2,4,6-trinitro-1,3-benzenediol, is a yellow astringent acid that forms hexagonal crystals. It is used in the manufacture of dyes, pigments, inks, medicines, and explosives such as lead styphnate...

), which forms yellow crystals, exploding violently on rapid heating.


Parts of a molecule of catechin
Catechin is a natural phenol antioxidant plant secondary metabolite. The term catechins is also commonly used to refer to the related family of flavonoids and the subgroup flavan-3-ols ....

, another natural compound that is present in tea
Tea is an aromatic beverage prepared by adding cured leaves of the Camellia sinensis plant to hot water. The term also refers to the plant itself. After water, tea is the most widely consumed beverage in the world...

, has the resorcinol skeleton structure in it.


Used externally, it is an antiseptic
Antiseptics are antimicrobial substances that are applied to living tissue/skin to reduce the possibility of infection, sepsis, or putrefaction...

 and disinfectant, and is used 5 to 10% in ointments in the treatment of chronic skin diseases such as psoriasis
Psoriasis is an autoimmune disease that appears on the skin. It occurs when the immune system mistakes the skin cells as a pathogen, and sends out faulty signals that speed up the growth cycle of skin cells. Psoriasis is not contagious. However, psoriasis has been linked to an increased risk of...

, hidradenitis suppurativa
Hidradenitis suppurativa
Hidradenitis suppurativa is a skin disease that most commonly affects areas bearing apocrine sweat glands or sebaceous glands, such as the underarms, breasts, inner thighs, groin and buttocks.-Overview:...

, and eczema
Eczema is a form of dermatitis, or inflammation of the epidermis . In England, an estimated 5.7 million or about one in every nine people have been diagnosed with the disease by a clinician at some point in their lives.The term eczema is broadly applied to a range of persistent skin conditions...

 of a sub-acute character. It is present in over-the-counter topical acne
Acne is a general term used for acneiform eruptions. It is usually used as a synonym for acne vulgaris, but may also refer to:*Acne aestivalis*Acne conglobata*Acne cosmetica*Acne fulminans*Acne keloidalis nuchae*Acne mechanica...

 treatments at 2% or less 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
Hay Fever
Hay Fever is a comic play written by Noël Coward in 1924 and first produced in 1925 with Marie Tempest as the first Judith Bliss. Laura Hope Crews played the role in New York...

 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
Dandruff is the shedding of dead skin cells from the scalp . Dandruff is sometimes caused by frequent exposure to extreme heat and cold. As it is normal for skin cells to die and flake off, a small amount of flaking is normal and common; about 487,000 cells/cm2 get released normally after...

 agent in shampoo
Shampoo is a hair care product used for the removal of oils, dirt, skin particles, dandruff, environmental pollutants and other contaminant particles that gradually build up in hair...

 or in sunscreen
Sunblock is a lotion, spray, gel or other topical product that absorbs or reflects some of the sun's ultraviolet radiation on the skin exposed to sunlight and thus helps protect against sunburn...

 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
An analgesic is any member of the group of drugs used to relieve pain . The word analgesic derives from Greek an- and algos ....

 and haemostatic in its
action. In large doses, it is a poison
In the context of biology, poisons are substances that can cause disturbances to organisms, usually by chemical reaction or other activity on the molecular scale, when a sufficient quantity is absorbed by an organism....

, causing giddiness, deafness, salivation, sweating
Perspiration is the production of a fluid consisting primarily of water as well as various dissolved solids , that is excreted by the sweat glands in the skin of mammals...

, and convulsions. It is also worked up in certain medicated soaps. Monoacetylresorcinol, C6H4(OH)(O-COCH3), is used under the name of euresol. Resorcinol is one of the main active ingredients in products like Resinol
Resinol is a skin protectant and topical analgesic that is made by ResiCal Inc. from Orchard Park, New York. It is an over-the-counter drug that can currently be purchased in 1.25 or 3.3 ounce jars by contacting a local pharmacy's drug wholesaler to order the item or on the...

 and Vagisil.
Resorcinol is also an active ingredient in certain Clearasil
Clearasil is the top-selling brand of skin care and acne medication, whose products contain chiefly benzoyl peroxide, sulfur & resorcinol, triclosan, or salicylic acid as active ingredients...



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
Supramolecular chemistry
Supramolecular chemistry refers to the area of chemistry beyond the molecules and focuses on the chemical systems made up of a discrete number of assembled molecular subunits or components...

. The -OH groups on resorcinol form hydrogen bond
Hydrogen bond
A hydrogen bond is the attractive interaction of a hydrogen atom with an electronegative atom, such as nitrogen, oxygen or fluorine, that comes from another molecule or chemical group. The hydrogen must be covalently bonded to another electronegative atom to create the bond...

s 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
Phase (matter)
In the physical sciences, a phase is a region of space , throughout which all physical properties of a material are essentially uniform. Examples of physical properties include density, index of refraction, and chemical composition...

, thereby reducing or eliminating the use of solvents that may be harmful to the environment. (see Green chemistry
Green chemistry
Green chemistry, also called sustainable chemistry, is a philosophy of chemical research and engineering that encourages the design of products and processes that minimize the use and generation of hazardous substances...


Resorcinol is an analytical reagent for the qualitative determinaion of ketoses (Seliwanoff's test
Seliwanoff's test
Seliwanoff’s test is a chemical test which distinguishes between aldose and ketose sugars. Ketoses are distinguished from aldoses via their ketone/aldehyde functionality. If the sugar contains a ketone group, it is a ketose and if it contains an aldehyde group, it is an aldose...


Resorcinol is the starting material for resorcinarene
A resorcinarene is a macrocycle, or a cyclic oligomer, based on the condensation of resorcinol and an aldehyde. Resorcinarenes are a type of calixarene.-Synthesis:...

 molecules and the initiating explosive lead styphnate (Reference: Army TM 9-1300-214, p. 7–12).

Resorcinol reacts with formaldehyde to form a thermoset resin, which can form the basis of an aerogel
Aerogel is a synthetic porous material derived from a gel, in which the liquid component of the gel has been replaced with a gas. The result is a solid with extremely low density and thermal conductivity...


Related compounds

Resazurin is a blue dye, itself nonfluorescent until it is reduced to the pink colored and highly red fluorescent resorufin. It is used mainly as an oxidation-reduction indicator in cell viability assays for bacteria and mammalian cells...

, C12H7NO4, 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, C12H7NO3, 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)2C6H2(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.

Alkylresorcinols are a class of phenolic lipids found in wheat or rye brans.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.