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. The ...
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, ...
C
6H
12O
7 and condensed
structural formula
The structural formula of a chemical compound is a graphic representation of the molecular structure (determined by structural chemistry methods), showing how the atoms are possibly arranged in the real three-dimensional space. The chemical bondi ...
HOCH
2(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 in ...
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 quantitie ...
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 ar ...
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 d ...
of
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, using ...
. 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 at ...
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 hydroxy ...
groups positioned in the same way as in the
open-chained form of glucose, terminating in a
carboxylic acid
In organic chemistry, a carboxylic acid is an organic acid that contains a carboxyl group () attached to an R-group. The general formula of a carboxylic acid is or , with R referring to the alkyl, alkenyl, aryl, or other group. Carboxylic ...
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 odorless ...
.
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
Fermentation is a metabolic process that produces chemical changes in organic substrates through the action of enzymes. In biochemistry, it is narrowly defined as the extraction of energy from carbohydrates in the absence of oxygen. In food ...
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
Food additives are substances added to food to preserve flavor or enhance taste, appearance, or other sensory qualities. Some additives have been used for centuries as part of an effort to preserve food, for example vinegar (pickling), salt (salt ...
(E574), it is now known as an
acidity regulator
Acidity regulators, or pH control agents, are food additives used to change or maintain pH (acidity or basicity). They can be organic or mineral acids, bases, neutralizing agents, or buffering agents. Typical agents include the following acids ...
.
The gluconate anion
chelates
Chelation is a type of bonding of ions and molecules to metal ions. It involves the formation or presence of two or more separate coordinate bonds between a polydentate (multiple bonded) ligand and a single central metal atom. These ligands are ...
Ca2+,
Fe2+,
,
Al3+, and other metals, including
lanthanide
The lanthanide () or lanthanoid () series of chemical elements comprises the 15 metallic chemical elements with atomic numbers 57–71, from lanthanum through lutetium. These elements, along with the chemically similar elements scandium and yttr ...
s 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 inform ...
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, removing ...
, where it dissolves mineral deposits, especially in alkaline solution.
Zinc gluconate
Zinc gluconate is the zinc salt of gluconic acid. It is an ionic compound consisting of two anions of gluconate for each zinc(II) cation. Zinc gluconate is a popular form for the delivery of zinc as a dietary supplement providing 14.35% elementa ...
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
Organic synthesis is a special branch of chemical synthesis and is concerned with the intentional construction of organic compounds. Organic molecules are often more complex than inorganic compounds, and their synthesis has developed into one o ...
.
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 no ...
, in the form of a gel, is used to treat burns from
hydrofluoric acid
Hydrofluoric acid is a Solution (chemistry), solution of hydrogen fluoride (HF) in water. Solutions of HF are colourless, acidic and highly Corrosive substance, corrosive. It is used to make most fluorine-containing compounds; examples include th ...
;
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 leg cr ...
gluconate is a salt of gluconic acid and quinine, which is used for
intramuscular injection
Intramuscular injection, often abbreviated IM, is the injection of a substance into a muscle. In medicine, it is one of several methods for parenteral administration of medications. Intramuscular injection may be preferred because muscles have ...
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
Iron(II) gluconate, or ferrous gluconate, is a black compound often used as an iron supplement. It is the iron(II) salt of gluconic acid. It is marketed under brand names such as ''Fergon'', ''Ferralet'' and ''Simron''.
Uses Medical
Ferrous glu ...
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, th ...
.
[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.]
See also
*
Uronic acid
300px, The Fischer projections of glucose and glucuronic acid">glucose.html" ;"title="Fischer projections of glucose">Fischer projections of glucose and glucuronic acid. Glucose's terminal carbon's primary alcohol group has been oxidized to a ...
*
Glucuronic acid
Glucuronic acid (from Greek γλεῦκος "''wine, must''" and οὖρον "''urine''") is a uronic acid that was first isolated from urine (hence the name). It is found in many gums such as gum arabic (c. 18%), xanthan, and kombucha tea and ...
*
Isosaccharinic acid
Isosaccharinic acid (ISA) is a six-carbon sugar acid which is formed by the action of calcium hydroxide on lactose and other carbohydrates. It is of interest because it may form in intermediate-level nuclear waste stores when cellulose is degrade ...
(ISA)
References
External links
Gluconic acid on NIST.gov
{{Authority control
Acids in wine
Alpha hydroxy acids
Chelating agents
Concrete admixtures
E-number additives
Food additives
Radioactive waste
Sugar acids
Vicinal diols