Gluconic acid is an

organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. T ...

with

molecular formula In chemistry, a chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, ...

C₆H₁₂O₇ and condensed structural formula HOCH₂(CHOH)₄COOH. It is one of the 16

stereoisomers In stereochemistry, stereoisomerism, or spatial isomerism, is a form of isomerism in which molecules have the same molecular formula and sequence of bonded atoms (constitution), but differ in the three-dimensional orientations of their atoms ...

of 2,3,4,5,6-pentahydroxyhexanoic acid. In aqueous solution at neutral pH, gluconic acid forms the gluconate ion. The

salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quant ...

s of gluconic acid are known as "gluconates". Gluconic acid, gluconate salts, and gluconate

ester In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides a ...

s occur widely in nature because such species arise from the

oxidation Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a ...

glucose Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, u ...

. Some drugs are injected in the form of gluconates.

Chemical structure

The

chemical structure A chemical structure determination includes a chemist's specifying the molecular geometry and, when feasible and necessary, the electronic structure of the target molecule or other solid. Molecular geometry refers to the spatial arrangement of ...

of gluconic acid consists of a six-carbon chain, with five

hydroxyl In chemistry, a hydroxy or hydroxyl group is a functional group with the chemical formula and composed of one oxygen atom covalently bonded to one hydrogen atom. In organic chemistry, alcohols and carboxylic acids contain one or more hydro ...

groups positioned in the same way as in the open-chained form of glucose, terminating in a carboxylic acid group. In aqueous solution, gluconic acid exists in equilibrium with the cyclic ester

glucono delta-lactone Glucono-delta-lactone (GDL), also known as gluconolactone, is a food additive with the E-number E575 used as a sequestrant, an acidifier, or a curing, pickling, or leavening agent. It is a lactone of D-gluconic acid. Pure GDL is a white odor ...

Production

Gluconic acid preparation was first reported by Hlasiwetz and Habermann in 1870 and involved the chemical oxidation of glucose. In 1880, Boutroux prepared and isolated gluconic acid using the glucose fermentation. Contemporary methods for the gluconic acid production utilize variations of glucose (or other carbohydrate-containing substrate) oxidation using fermentation or

noble metal A noble metal is ordinarily regarded as a metallic chemical element that is generally resistant to corrosion and is usually found in nature in its raw form. Gold, platinum, and the other platinum group metals ( ruthenium, rhodium, palladium, o ...

catalysis.

Occurrence and uses

Gluconic acid occurs naturally in

fruit In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering. Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in particu ...

honey Honey is a sweet and viscous substance made by several bees, the best-known of which are honey bees. Honey is made and stored to nourish bee colonies. Bees produce honey by gathering and then refining the sugary secretions of plants (primar ...

, and

wine Wine is an alcoholic drink typically made from fermented grapes. Yeast consumes the sugar in the grapes and converts it to ethanol and carbon dioxide, releasing heat in the process. Different varieties of grapes and strains of yeasts are m ...

. As a food additive (E574), it is now known as an acidity regulator. The gluconate anion chelates Ca²⁺, Fe²⁺, , Al³⁺, and other metals, including lanthanides and

actinide The actinide () or actinoid () series encompasses the 15 metallic chemical elements with atomic numbers from 89 to 103, actinium through lawrencium. The actinide series derives its name from the first element in the series, actinium. The info ...

s. It is also used in

cleaning products Cleaning agents or hard-surface cleaners are substances (usually liquids, powders, sprays, or granules) used to remove dirt, including dust, stains, bad smells, and clutter on surfaces. Purposes of cleaning agents include health, beauty, removin ...

, where it dissolves mineral deposits, especially in alkaline solution. Zinc gluconate injections are used to neuter male dogs. Gluconate is also used in building and construction as a concrete admixture (retarder) to slow down the cement hydration reactions, and to delay the cement setting time. It allows for a longer time to lay the concrete, or to spread the cement hydration heat over a longer period of time to avoid too high a temperature and the resulting cracking. Retarders are mixed in to concrete when the weather temperature is high or to cast large and thick concrete slabs in successive and sufficiently well-mixed layers. Gluconic acid aqueous solution finds application as a medium for organic synthesis.

Medicine

In medicine, gluconate is used most commonly as a biologically neutral carrier of , , , , and to treat

electrolyte imbalance Electrolyte imbalance, or water-electrolyte imbalance, is an abnormality in the concentration of electrolytes in the body. Electrolytes play a vital role in maintaining homeostasis in the body. They help to regulate heart and neurological function, ...

Calcium gluconate Calcium gluconate is a mineral supplement and medication. As a medication it is used by injection into a vein to treat low blood calcium, high blood potassium, and magnesium toxicity. Supplementation is generally only required when there is n ...

, in the form of a gel, is used to treat burns from hydrofluoric acid; calcium gluconate injections may be used for more severe cases to avoid necrosis of deep tissues, as well as to treat hypocalcemia in hospitalized patients. Gluconate is also an electrolyte present in certain solutions, such as " plasmalyte a", used for intravenous fluid resuscitation.

Quinine Quinine is a medication used to treat malaria and babesiosis. This includes the treatment of malaria due to '' Plasmodium falciparum'' that is resistant to chloroquine when artesunate is not available. While sometimes used for nocturnal le ...

gluconate is a salt of gluconic acid and quinine, which is used for intramuscular injection in the treatment of

malaria Malaria is a mosquito-borne infectious disease that affects humans and other animals. Malaria causes symptoms that typically include fever, tiredness, vomiting, and headaches. In severe cases, it can cause jaundice, seizures, coma, or death. S ...

. Ferrous gluconate injections have been proposed in the past to treat

anemia Anemia or anaemia (British English) is a blood disorder in which the blood has a reduced ability to carry oxygen due to a lower than normal number of red blood cells, or a reduction in the amount of hemoglobin. When anemia comes on slowly, t ...

.Paul Reznikoff and Walther F. Goebel (1937), ''The preparation of ferrous gluconate and its use in the treatment of hypochromic anelia in rats.'' Journal of Pharmacology and Experimental Therapy, volume 59 issue 2, page 182.

References

External links