TANNIC ACID

Tannic acid is a pale yellow amorphous powder or a shiny, scaly-like, or sponge-like solid.
Tannic acid has no distinct odor, with a bitter taste and strong astringency.
Tannic acid gradually darkens upon exposure to air and sunlight.

CAS Number: 1401-55-4
Molecular Formula: C76H52O46
Molecular Weight: 1701.2
EINECS Number: 215-753-2

Synonyms: Tannic acid, Gallotannic acid, Tannicum acidum, Acid, tannic, Acide tannique, d’Acide tannique, Glycerite, Tannin (tannic acid), TANNICACID, tannic-acid, Tannin from mimosa, Mimosa tannin, Acacia mollissima tannin, Tannin from chestnut, Chestnut tannin, Castanea sativa Mill tannin, Tannin from quebracho, Schinopsis lorentzii tannin, Tannic acid (Quercus spp.), Asian holly oak nutgall, Chinese gallotannin, CAS 1401-55-4, EINECS 226-562-9, FEMA No. 3042, CHEBI:75211, CHEBI:81066, RefChem:6282, CHEMBL506247, NSC-656273, NSC-758670, DTXSID2026076, DTXSID00892987, DSSTox_CID_6076, DSSTox_RID_78006, DSSTox_GSID_26076, Beta-D-glucose pentakis(3,4-dihydroxy-5-((3,4,5-trihydroxybenzoyl)oxy)benzoate), β-D-Glucopyranose pentakis[3,4-dihydroxy-5-[(3,4,5-trihydroxybenzoyl)oxy]benzoate], 1,2,3,4,6-Pentakis-O-{3,4-dihydroxy-5-[(3,4,5-trihydroxybenzoyl)oxy]benzoyl}-β-D-glucopyranose, C76H52O46, Q427956, cid_16129778, MFCD00066397, MLS001335996, MLS001335995, SCHEMBL409692, SCHEMBL29351681, SCHEMBL29451248, BDBM60986, BDBM50442879, AKOS015951319, abcolsumack19;abcoltannicacidtech;abcoltannicacidusp/kosher;acaciamollissimatannin;acid,tannic;acidetannique;castaneasativamilltannin;chestnuttannin

Tannic acid is soluble in cold water and infinitely soluble in hot water, and it is also soluble in methanol, ethanol, acetone, and ethyl acetate, but insoluble in benzene, ether, chloroform, petroleum ether, and carbon disulfide.
The aqueous solution of tannic acid exhibits weak acidity and is easily oxidized, with the oxidation rate being faster in alkaline solutions and the solution color becoming deeper.
In the presence of trivalent iron ions, the solution exhibits a blue-black color and can react with gelatin and alkaloids to form precipitates.

Tannic acid can also react with metal ions such as lead, aluminum, and zinc to generate polynuclear complexes and insoluble salts with characteristic colors.
When heated to 210–215 °C, tannic acid decomposes into pyrogallic acid and carbon dioxide.
Tannic acid has low toxicity; however, high intake can cause vomiting, abdominal pain, and diarrhea, and may also lead to circulatory system disorders that can be fatal, with an LD₁₀₀ of 6.0 g/kg (rat, oral).
At high temperatures, it decomposes to form pyrogallol and carbon dioxide.

Commercially available tannic acid typically contains approximately 10% moisture.
Tannic acid is a naturally occurring plant polyphenol and can be found in virtually all aerial plant tissues.
Historically, tannic acid was used for the treatment of diarrhea, applied topically for dressing skin burns, and administered rectally for the treatment of unspecified rectal disorders.

Its pharmaceutical use has been discontinued due to the availability of safer and more effective alternatives.
An unusually high incidence of esophageal cancer has been reported in certain regions of South Africa, where tannin-rich sorghum is consumed.
A positive correlation has been observed between the tannin content of sorghum and the incidence of esophageal cancer.

Tannic acid, or hydrolysable gallotannin, is a complex polyphenolic organic compound that yields gallic acid and either glucose or quinic acid as hydrolysis products.
Tannic acid is odorless or has a faint characteristic odor and possesses an astringent taste.
Tannic acid is a polyphenolic compound and represents one of the commercially available tannins.

Tannic acid acts as a weak acid.
Tannic acid is found in nutgalls formed by insects on the twigs of certain oak trees, including Quercus infectoria and other Quercus species.
It is extracted and used as a medicinal substance.

Historically, Tannic acid was used as an antidote against various poisons.
Currently, tannic acid is applied topically for the treatment of cold sores, diaper rash, fever blisters, and poison ivy.
Tannic acid is also taken orally or applied directly for the treatment of bleeding, chronic diarrhea, dysentery, hematuria, painful joints, persistent coughs, and cancer.

Tannic acid is a naturally occurring polyphenolic compound belonging to the group of plant tannins.
It is generally classified as a hydrolyzable gallotannin, composed of a glucose core esterified with multiple gallic acid units.
The exact molecular structure of tannic acid is not completely defined, as it represents a mixture of closely related galloyl glucose esters rather than a single uniform compound.

Upon hydrolysis, tannic acid yields gallic acid and glucose or, in some cases, quinic acid.
Tannic acid is widely distributed in nature and is found in many aerial plant tissues, particularly in oak galls, chestnut wood, mimosa bark, quebracho wood, and gall nuts formed by insect activity.
These natural sources serve as the primary raw materials for industrial extraction.

Physically, tannic acid appears as a pale yellow to light brown amorphous powder or scaly solid.
Tannic acid is odorless or nearly odorless, with a strong astringent and bitter taste, and it darkens gradually upon exposure to air and light.
Chemically, tannic acid behaves as a weak organic acid and exhibits strong protein-binding, metal-chelating, and antioxidant properties.

Tannic acid readily forms insoluble complexes with proteins, alkaloids, and metal ions, which underlies many of its practical applications.
Based on chemical behavior, tannins are classified into hydrolyzable tannins, such as tannic acid, and condensed tannins, which are not hydrolyzable.

Tannic acid is the most commercially important representative of hydrolyzable tannins.
Because of these properties, tannic acid has been historically and industrially used in leather tanning, medicine, food and beverage clarification, analytical chemistry, and materials processing.

Melting point : 218 °C
Boiling point : 862.78 °C (rough estimate)
Density : 1.2965 (rough estimate)
Refractive index : 1.7040 (estimate)
FEMA : 3042 | TANNIC ACID (QUERCUS SPP.)
Flash point : 198 °C
Storage temperature : No restrictions
Solubility : Ethanol, soluble at 100 mg/mL (yellow to brown solution)
Form : Powder / Solid
Color : Yellow to light brown
pH : 3.5 (100 g/L, H₂O, 20 °C)
Odor : Slight in solution, typical tannic acid
Biological source : Synthetic
Water solubility : 250 g/L (20 °C)
Sensitivity : Air and light sensitive
Merck Index : 14,9052
BRN : 8186396
Stability : Stable; incompatible with metallic salts, strong oxidizing agents, iron, and other heavy metals
Major application : Pharma / biopharma processes
Cosmetic ingredient functions : Fragrance; astringent
LogP : 13.327 (estimated)
InChIKey : LRBQNJMCXXYXIU-PPKXGCFTSA-N

Tannic acid is a naturally occurring high–molecular-weight polyphenolic compound that belongs to the tannin family, a group of secondary plant metabolites widely distributed in the plant kingdom.
Tannic acid is most commonly classified as a hydrolyzable gallotannin, meaning that its structure can be cleaved by acids, bases, or enzymes to yield simpler phenolic compounds.

Structurally, tannic acid is generally described as an ester formed between a central glucose molecule and multiple gallic acid units.
Although it is often represented by an idealized chemical formula, tannic acid does not exist as a single, well-defined molecule but rather as a mixture of closely related galloyl glucose esters with varying degrees of substitution.
Upon hydrolysis, tannic acid produces gallic acid and glucose, which confirms its classification as a hydrolyzable tannin.

Tannic acid occurs naturally in a wide range of plants and is especially abundant in oak galls, gall nuts, chestnut wood, mimosa bark, quebracho wood, and certain fruits and leaves.
Oak galls, formed as a result of insect activity on oak trees, are among the richest natural sources and have historically been used for commercial extraction.
Industrial tannic acid is typically obtained by aqueous extraction of these plant materials, followed by concentration, purification, and drying.

In its pure or commercial form, tannic acid appears as a pale yellow to light brown amorphous powder or scaly solid.
It is odorless or nearly odorless and is characterized by a strongly astringent and bitter taste, which is a direct result of its ability to bind and precipitate proteins.
Tannic acid is readily soluble in water and polar organic solvents such as ethanol, while showing poor solubility in nonpolar solvents.

From a chemical standpoint, tannic acid behaves as a weak organic acid and exhibits pronounced chelating, reducing, and antioxidant properties.
It readily forms complexes with metal ions such as iron, aluminum, copper, and zinc, as well as with proteins, alkaloids, and polysaccharides, often resulting in insoluble precipitates.
These interactions explain many of its functional properties, including its role as a tanning agent, clarifying agent, and analytical reagent.

Tannins, as a broader class, are divided into hydrolyzable tannins (such as tannic acid) and condensed tannins, which are polymeric flavonoid-based compounds resistant to hydrolysis.
Among hydrolyzable tannins, tannic acid is the most widely studied and commercially important representative.
Tannic acid is mainly used as a dyeing mordant and is also used in the preparation of gallic acid and gallic acid pyrophosphate.

Tannic acid can also be used in the manufacture of leather tanning agents, rubber coagulants, and as a precipitating agent for proteins and alkaloids, as well as a reagent for the determination of beryllium, aluminum, nickel, and copper.
The light yellow to light brown amorphous powder obtained by evaporation and drying of the aqueous extract of galls is industrial tannic acid, with a tannic acid content of more than 80%.
It also contains small amounts of gallic acid, m-gallic acid, trigalloylgallic acid, and pentagalloylglucose.

Tannic acid has 1,3,4,6-tetra-O-galloyl-2-multi-O-galloyl-β-D-glucose as its core structure and is an ester formed by the combination of one glucose molecule with 8 to 9 gallic acid units.
Tannic acid is susceptible to acid or enzymatic hydrolysis, with gallic acid and glucose as the hydrolysis products.
These aphids carry out their parasitic life cycle on the leaves of certain plants of the family Anacardiaceae, particularly Rhus chinensis.

When the tender tissues of the host plant are subjected to mechanical and chemical stimulation by the aphids, abnormal growth occurs, resulting in swelling into irregular spherical, spindle-shaped, or cystic gall bodies with horn-like protrusions or flower-like appearances.
During parasitism, aphids obtain nutrients from the host plant while secreting saliva containing large amounts of enzymes, which enter the cambium through the feeding site.
As a result, cellular metabolism in the surrounding tissue is enhanced, stimulating meristematic cell activity.

Within the gall, aphids continuously proliferate and feed, causing the gall body to enlarge progressively.
In the initial stage, only a single aphid is present inside the gall; however, after several generations of reproduction, the population increases dramatically.
In the final generation, winged aphids emerge, the gall shell ruptures, and the aphids leave the gall and migrate to winter host plants (moss-type plants) to overwinter.

In the following year, they return to the primary host plant, Rhus chinensis, for reproduction, leading to the re-formation of galls.
Tannic acid can inhibit bacterial growth and intestinal absorption of toxins and can be used for the prevention and treatment of diarrhea.

Medicinal tannic acid can be directly used in beverages, frozen products, candy, ice cream, and meat products; as an astringent for burn wounds; as a gastric hemostatic agent; and for infection prevention.
Tannic acid can also be formulated into tannic acid glycerol, tannic acid protein complexes, tannic acid ointments, antipyretic agents (such as N-bis-amidino morpholino tannic acid), health-promoting agents, insect repellents, pesticides, radiation-protective agents, contraceptive agents, and special-effect toothpaste.

Uses Of Tannic acid:
Tannic acid is suitable for tanning harness leather, sole leather, and sheepskin.
Tannic acid is recommended to store it in a cool, dry, and well-ventilated warehouse.
Tannic acid is preferably used in combination with other tanning agents.

Tannic acid is mainly used for tanning and can also be applied in the pharmaceutical, ink, printing, rubber, metallurgical, and water treatment industries.
Tannic acid can be used for tanning, fishing net dyeing, boiler cleaning, drilling, and related applications.
It can be used as an analytical reagent and is also applied in the pharmaceutical industry.

It can be used for pH adjustment during pelt pickling and vegetable tanning solutions, as well as for vegetable tanning rinses.
Due to its strong acidity, it should not be packed in iron containers.
It should be stored in a cool warehouse.

Tannic acid can be used as a water-based drilling fluid viscosity reducer and as a cement retarder.
In the pharmaceutical industry, it can be used as a raw material for the preparation of gallic acid, pyrogallol, and sulfonamide drugs.
Tannin is a type of hemostatic agent.

In the medical field, it has been used for the treatment of pharyngitis, tonsillitis, hemorrhoids, and skin blistering disorders, while internal administration can inhibit diarrhea and intestinal hemorrhage.
Tannin can react with metals, alkaloids, and glycosides to form precipitates, thereby exerting a detoxifying effect against these substances.
Tannin can be used for leather tanning and the manufacture of ink, paper, and silk sizing agents, as well as for boiler cleaning.

Tannic acid can also be used as a mordant, a clarifying agent for beer and wine, a coagulating agent for rubber, and as a reagent for the determination of beryllium, aluminum, nickel, and copper.
In chemical production, it is used for the preparation of gallic acid and gallic acid pyrophosphate.
Tannin is used for dilution in drilling mud treatment.

When tannin powder is mixed proportionally with caustic soda, an alkaline tannin solution is obtained, which reduces the shear force of thickened and sticky mud and improves mud flow properties.
Conversely, when tannin powder is added directly to drilling mud, its weak acidity reduces the pH of the mud.
Through ion exchange with clay particles, it reduces surface hydration of the clay, leading to the formation of a clay particle network structure and improving the shear strength and viscosity of the mud.

According to the provisions of GB2760-89 of China, “curing tannins” may be used in low-alcohol wines and wines as clarifying agents to remove proteins responsible for turbidity and other suspended substances.
In the food industry, tannin can also be used as an astringent agent and a crude oil deodorizer.
Tannic acid can be used for the precipitation and gravimetric determination of beryllium, aluminum, gallium, indium, niobium, tantalum, and zirconium.

It can also be used for the colorimetric determination of copper, iron, vanadium, cerium, and cobalt.
Tannic acid can serve as a precipitating reagent for proteins and alkaloids and may also be used as an external indicator in the titration of lead with molybdate.
Tannic acids are phenolic compounds containing multiple hydrolyzable groups.

They are classified as (a) hydrolyzable tannins, which yield phenols such as gallic acid in the presence of acid and heat, and (b) condensed tannins, which are obtained from oak extracts and are not hydrolyzable.
Tannic acids are used for their taste and chemical properties and function as sequestrants.
They influence the color and flavor of fruits and vegetables.

They are used in fruits, wine, and beer to remove undesirable substances by forming insoluble complexes with proteins.
Tannic acid is a powder extracted from gall nuts that is soluble in water but less soluble in alcohol.
In the mid-1850s, tannic acid was used by Major Russell in the tannin process for preparing dry collodion plates.

In this process, the collodion plate was coated and sensitized as usual, after which excess silver was completely washed from the surface.
A solution of tannic acid was then applied to and removed from the plate, and the collodion film was allowed to dry completely in the dark.
The tannin-treated plate could be preserved for several months prior to exposure.

After exposure, the plate was developed using pyrogallic acid, citric acid, and silver nitrate to replace the silver removed during initial preparation.
Exposure times required for tannin plates were up to five times longer than those for wet collodion plates, making them suitable primarily for landscape photography.
Tannic acid is widely used as a vegetable tanning agent for harness leather, sole leather, sheepskin, and other hides, where it improves strength, durability, and resistance by crosslinking collagen fibers.

Tannic acid is also employed as a mordant in textile dyeing and fishing net coloring, enhancing dye fixation and color stability.
In industrial and chemical applications, tannic acid is used in the production of gallic acid, pyrogallol, and gallic acid pyrophosphate.
It functions as a rubber coagulant, a cement retarder, and a water-based drilling fluid viscosity reducer, improving the flow and shear behavior of drilling muds.

Tannic acid is additionally used for boiler cleaning and scale control.
In analytical chemistry and metallurgy, tannic acid serves as a precipitating reagent for proteins and alkaloids.
It is applied in the gravimetric and colorimetric determination of metals such as beryllium, aluminum, gallium, indium, niobium, tantalum, zirconium, copper, iron, vanadium, cerium, and cobalt.

Tannic acid can also be used as an external indicator in titration methods, including the determination of lead using molybdate.
In pharmaceutical and medical fields, tannic acid has historically been used as an astringent and hemostatic agent.
It has been applied in the treatment of diarrhea, intestinal hemorrhage, burns, skin blistering disorders, hemorrhoids, pharyngitis, and tonsillitis, and has been formulated into ointments, glycerol solutions, and protein complexes.

Many internal medical uses have been discontinued due to safety concerns and the availability of safer alternatives.
In the food and beverage industry, tannic acid is used as a clarifying agent in beer, wine, and low-alcohol beverages by removing proteins and other suspended substances responsible for turbidity.
Tannic acid may also be used as an astringent agent and as a deodorizer for crude oils in food processing, subject to regulatory approval.

Safety Profile Of Tannic acid:
Tannic acid may cause skin and eye irritation upon direct contact due to its strong astringent and protein-precipitating properties.
Prolonged or repeated exposure can lead to skin dryness, irritation, or dermatitis, especially in occupational settings.
Inhalation of tannic acid dust may irritate the respiratory tract, causing coughing, throat discomfort, and breathing difficulty in sensitive individuals.

Adequate ventilation and dust control measures are recommended during handling.
Ingestion of large amounts of tannic acid can result in gastrointestinal irritation, including nausea, vomiting, abdominal pain, and diarrhea.
Excessive intake may interfere with iron absorption and can lead to systemic toxicity, including circulatory disturbances, with severe cases potentially being fatal.

Tannic acid can undergo oxidation, particularly in alkaline environments, leading to darkening and degradation, which may affect product stability and performance.
At elevated temperatures, it decomposes to produce pyrogallol and carbon dioxide, and thermal decomposition products may pose additional health risks.