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44-411: Nettle refers to plants with stinging hairs , particularly those of the genus Urtica . It can also refer to plants which resemble Urtica species in appearance but do not have stinging hairs. Plants called "nettle" include: Stinging plant Other plants, such as opuntias , have hairs or spines that cause mechanical irritation, but do not inject chemicals. Stinging hairs occur particularly in

88-463: A mutagen . Chronic exposure in humans may cause kidney damage. Another possible effect of chronic exposure is development of a skin allergy that manifests upon re-exposure to the chemical. Concentrated formic acid slowly decomposes to carbon monoxide and water, leading to pressure buildup in the containing vessel. For this reason, 98% formic acid is shipped in plastic bottles with self-venting caps. The hazards of solutions of formic acid depend on

132-463: A large excess of water. Some routes proceed indirectly by first treating the methyl formate with ammonia to give formamide , which is then hydrolyzed with sulfuric acid : A disadvantage of this approach is the need to dispose of the ammonium sulfate byproduct. This problem has led some manufacturers to develop energy-efficient methods of separating formic acid from the excess water used in direct hydrolysis. In one of these processes, used by BASF ,

176-485: A large-scale source of formate by various groups. The formate could be used as feed to modified E. coli bacteria for producing biomass . Natural methylotroph microbes can feed on formic acid or formate. Formic acid has been considered as a means of hydrogen storage . The co-product of this decomposition, carbon dioxide, can be rehydrogenated back to formic acid in a second step. Formic acid contains 53 g/L hydrogen at room temperature and atmospheric pressure, which

220-696: A lower temperature, reducing the loss of nutritional value. It is widely used to preserve winter feed for cattle , and is sometimes added to poultry feed to kill E. coli bacteria. Use as a preservative for silage and other animal feed constituted 30% of the global consumption in 2009. Beekeepers use formic acid as a miticide against the tracheal mite ( Acarapis woodi ) and the Varroa destructor mite and Varroa jacobsoni mite . Formic acid can be used directly in formic acid fuel cells or indirectly in hydrogen fuel cells . Electrolytic conversion of electrical energy to chemical fuel has been proposed as

264-506: A point that easily breaks off, allowing the irritants in the cell below to enter through the skin. Being stung in this way has been shown to deter grazing mammals, such as rabbits, and even large herbivores such as cows. Many plant species respond to physical damage by producing a higher density of trichomes of all kinds. The general structure of a stinging hair is very similar in all the families of plants that possess them (except Tragia and Dalechampia ). A multicellular base supports

308-551: A preservative and antibacterial in livestock feed. Formic acid is a colorless liquid having a pungent, penetrating odor at room temperature, comparable to the related acetic acid . Formic acid is about ten times stronger than acetic acid . It is miscible with water and most polar organic solvents , and is somewhat soluble in hydrocarbons . In hydrocarbons and in the vapor phase, it consists of hydrogen-bonded dimers rather than individual molecules. Owing to its tendency to hydrogen-bond, gaseous formic acid does not obey

352-495: A single long thin cell, typically 1–8 mm long, with a brittle tip that easily breaks to form a sharp point that can penetrate skin. Stinging hairs of Urtica species have been studied in some detail. Each hair contains a fine tube, stiffened with calcium carbonate (calcified) at its base and with silica (silicified) at its tip. In Urtica thunbergiana , individual hairs contain around 4 nanolitres ( 4 × 10  ml ) of fluid. The silicified tip breaks off on contact, and

396-452: Is a neurotransmitter . When it is released naturally, inflammation of the skin results, causing pain and itching. Injection of histamine by stinging hairs has been considered to have the same effect. This traditional interpretation was challenged in 2006 by research on Urtica thunbergiana , the main species of Urtica present in Taiwan . In tests on rats, the long-lasting pain caused by stings

440-510: Is a convenient laboratory source of CO. In the presence of platinum , it decomposes with a release of hydrogen and carbon dioxide . Soluble ruthenium catalysts are also effective for producing carbon monoxide-free hydrogen. Formic acid shares most of the chemical properties of other carboxylic acids . Because of its high acidity, solutions in alcohols form esters spontaneously; in Fischer esterifications of formic acid, it self-catalyzes

484-492: Is a naturally occurring component of the atmosphere primarily due to forest emissions. As early as the 15th century, some alchemists and naturalists were aware that ant hills give off an acidic vapor. The first person to describe the isolation of this substance (by the distillation of large numbers of ants) was the English naturalist John Ray , in 1671. Ants secrete the formic acid for attack and defense purposes. Formic acid

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528-426: Is also used in place of mineral acids for various cleaning products, such as limescale remover and toilet bowl cleaner . Some formate esters are artificial flavorings and perfumes. Formic acid application has been reported to be an effective treatment for warts . Formic acid has low toxicity (hence its use as a food additive), with an LD 50 of 1.8   g/kg (tested orally on mice). The concentrated acid

572-435: Is an important intermediate in chemical synthesis and occurs naturally, most notably in some ants. Esters , salts and the anion derived from formic acid are called formates . Industrially, formic acid is produced from methanol . Formic acid is found naturally in insects, weeds, fruits and vegetables, and forest emissions. It appears in most ants and in stingless bees of the genus Oxytrigona . Wood ants from

616-474: Is based on the reaction of formate with bacterial formate dehydrogenase . A major use of formic acid is as a preservative and antibacterial agent in livestock feed. It arrests certain decay processes and causes the feed to retain its nutritive value longer, In Europe, it is applied on silage , including fresh hay, to promote the fermentation of lactic acid and to suppress the formation of butyric acid ; it also allows fermentation to occur quickly, and at

660-438: Is corrosive to the skin. Formic acid is readily metabolized and eliminated by the body. Nonetheless, it has specific toxic effects; the formic acid and formaldehyde produced as metabolites of methanol are responsible for the optic nerve damage, causing blindness, seen in methanol poisoning . Some chronic effects of formic acid exposure have been documented. Some experiments on bacterial species have demonstrated it to be

704-404: Is evolved at the anode, the total reaction is: Formic acid is named after ants which have high concentrations of the compound in their venom, derived from serine through a 5,10-methenyltetrahydrofolate intermediate. The conjugate base of formic acid, formate, also occurs widely in nature. An assay for formic acid in body fluids, designed for determination of formate after methanol poisoning,

748-501: Is generally similar. A solid base supports a single elongated cell with a brittle tip. When the tip is broken, the exposed sharp point penetrates the skin and pressure injects toxins. The precise chemicals involved in causing pain and irritation are not yet fully understood. Stiff hairs or trichomes without the ability to inject irritating compounds occur on the leaves and stems of many plants. They appear to deter feeding insects to some degree by impeding movement and restricting access to

792-405: Is heated to higher temperatures, allyl alcohol results. The net reaction is thus: Another illustrative method involves the reaction between lead formate and hydrogen sulfide , driven by the formation of lead sulfide . Formate is formed by the electrochemical reduction of CO 2 (in the form of bicarbonate ) at a lead cathode at pH 8.6: or If the feed is CO 2 and oxygen

836-443: Is known: a lightly clad young man died five hours after walking through a dense patch. After cooking, some plants with stinging hairs, such as Urtica dioica (stinging nettle), are eaten as vegetables. Formic acid Formic acid (from Latin formica  ' ant '), systematically named methanoic acid , is the simplest carboxylic acid , and has the chemical formula HCOOH and structure H−C(=O)−O−H . It

880-490: Is then intensified by the effect of the oxalate. The effects of the stinging hairs of Urtica species, particularly some subspecies of Urtica dioica , have been attributed to a number of substances, including histamine , acetylcholine , serotonin , and formic acid . Histamine is a component of the stinging hairs of other Urtica species (e.g. U. urens and U. parviflora ) and of Cnidoscolus urens and Laportea species. In vertebrates , histamine

924-554: Is three and a half times as much as compressed hydrogen gas can attain at 350 bar pressure (14.7 g/L). Pure formic acid is a liquid with a flash point of 69 °C, much higher than that of gasoline (−40 °C) or ethanol (13 °C). It is possible to use formic acid as an intermediary to produce isobutanol from CO 2 using microbes. Formic acid has a potential application in soldering . Due to its capacity to reduce oxide layers, formic acid gas can be blasted at an oxide surface to increase solder wettability . Formic acid

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968-519: Is used as a volatile pH modifier in HPLC and capillary electrophoresis . Formic acid is often used as a component of mobile phase in reversed-phase high-performance liquid chromatography (RP-HPLC) analysis and separation techniques for the separation of hydrophobic macromolecules, such as peptides, proteins and more complex structures including intact viruses. Especially when paired with mass spectrometry detection, formic acid offers several advantages over

1012-463: The families Urticaceae , Loasaceae , Boraginaceae (subfamily Hydrophylloideae ) and Euphorbiaceae . Such hairs have been shown to deter grazing mammals, but are no more effective against insect attack than non-stinging hairs. Many plants with stinging hairs have the word "nettle" in their English name, but may not be related to "true nettles" (the genus Urtica ). Though several unrelated families of plants have stinging hairs, their structure

1056-545: The Eschweiler–Clarke reaction : It is used as a source of hydrogen in transfer hydrogenation , as in the Leuckart reaction to make amines , and (in aqueous solution or in its azeotrope with triethylamine ) for hydrogenation of ketones . Formic acid is unique among the carboxylic acids in its ability to participate in addition reactions with alkenes . Formic acids and alkenes readily react to form formate esters . In

1100-484: The ideal gas law . Solid formic acid, which can exist in either of two polymorphs , consists of an effectively endless network of hydrogen-bonded formic acid molecules. Formic acid forms a high-boiling azeotrope with water (107.3 °C; 77.5% formic acid). Liquid formic acid tends to supercool . Formic acid readily decomposes by dehydration in the presence of concentrated sulfuric acid to form carbon monoxide and water: Treatment of formic acid with sulfuric acid

1144-530: The United States. When methanol and carbon monoxide are combined in the presence of a strong base , the result is methyl formate , according to the chemical equation : In industry, this reaction is performed in the liquid phase at elevated pressure. Typical reaction conditions are 80 °C and 40 atm. The most widely used base is sodium methoxide . Hydrolysis of the methyl formate produces formic acid: Efficient hydrolysis of methyl formate requires

1188-450: The aforementioned dedicated routes to formic acid have become more important. The catalytic hydrogenation of CO 2 to formic acid has long been studied. This reaction can be conducted homogeneously. Formic acid can also be obtained by aqueous catalytic partial oxidation of wet biomass by the OxFA process . A Keggin-type polyoxometalate (H 5 PV 2 Mo 10 O 40 ) is used as

1232-541: The concentration. The following table lists the Globally Harmonized System of Classification and Labelling of Chemicals for formic acid solutions: Formic acid in 85% concentration is flammable, and diluted formic acid is on the U.S. Food and Drug Administration list of food additives. The principal danger from formic acid is from skin or eye contact with the concentrated liquid or vapors. The U.S. OSHA Permissible Exposure Level ( PEL ) of formic acid vapor in

1276-405: The difference between "stinging hairs" and "irritating hairs" is not always clear. For example, the hairs of Mucuna species are described in both ways. Some species of Mucuna have sharply tipped hairs, in which the upper part easily breaks off, whereas other species have hairs that are blunter. In those subspecies of Urtica dioica that have stinging hairs (stinging nettles), these also have

1320-409: The formic acid is removed from the water by liquid-liquid extraction with an organic base. A significant amount of formic acid is produced as a byproduct in the manufacture of other chemicals. At one time, acetic acid was produced on a large scale by oxidation of alkanes , by a process that cogenerates significant formic acid. This oxidative route to acetic acid has declined in importance so that

1364-574: The genus Formica can spray formic acid on their prey or to defend the nest. The puss moth caterpillar ( Cerura vinula ) will spray it as well when threatened by predators. It is also found in the trichomes of stinging nettle ( Urtica dioica ). Apart from that, this acid is incorporated in many fruits such as pineapple (0.21 mg per 100 g), apple (2 mg per 100 g) and kiwi (1 mg per 100 g), as well as in many vegetables, namely onion (45 mg per 100 g), eggplant (1.34 mg per 100 g) and, in extremely low concentrations, cucumber (0.11 mg per 100 g). Formic acid

List of plants known as nettle - Misplaced Pages Continue

1408-477: The genus Urtica in the family Urticaceae fall into this category, with a cosmopolitan though mainly temperate distribution. They are mostly herbaceous perennial plants , but some are annual and a few are shrubby . The most prominent member of the genus Urtica is the stinging nettle , Urtica dioica , native to Europe , Africa , Asia , and North America . The family Urticaceae also contains some other plants with stinging hairs that are not members of

1452-535: The genus Urtica . These include: There are also plants with stinging hairs that are unrelated to the Urticaceae: Though plants with stinging hairs can cause pain and acute urticaria , only a few are seriously harmful. The genus Dendrocnide (stinging trees) has been said to cause the most pain, particularly the Australian Dendrocnide moroides (gympie-gympie), although other sources describe

1496-419: The homogeneous catalyst to convert sugars, wood, waste paper, or cyanobacteria to formic acid and CO 2 as the sole byproduct. Yields of up to 53% formic acid can be achieved. In the laboratory, formic acid can be obtained by heating oxalic acid in glycerol followed by steam distillation. Glycerol acts as a catalyst, as the reaction proceeds through a glyceryl oxalate intermediate. If the reaction mixture

1540-673: The largest producers are BASF , Eastman Chemical Company , LC Industrial , and Feicheng Acid Chemicals , with the largest production facilities in Ludwigshafen (200 thousand tonnes or 440 million pounds per year, BASF, Germany), Oulu (105 thousand tonnes or 230 million pounds, Eastman, Finland), Nakhon Pathom (n/a, LC Industrial), and Feicheng (100 thousand tonnes or 220 million pounds, Feicheng, China). 2010 prices ranged from around €650/tonne (equivalent to around $ 800/tonne) in Western Europe to $ 1250/tonne in

1584-399: The more traditionally used phosphoric acid . Formic acid is also significantly used in the production of leather, including tanning (23% of the global consumption in 2009 ), and in dyeing and finishing textiles (9% of the global consumption in 2009 ) because of its acidic nature. Use as a coagulant in the production of rubber consumed 6% of the global production in 2009. Formic acid

1628-447: The pain of stinging trees as only differing from that of nettles in terms of persistence rather than severity. There are reports of dogs and horses being killed, and once of a human death. The researcher Marina Hurley reports being hospitalized after being stung by a dead leaf. Deaths are probably due to heart failure caused by pain and shock. Urtica ferox (tree nettle or ongaonga) is endemic to New Zealand . One recorded human death

1672-484: The presence of certain acids, including sulfuric and hydrofluoric acids , however, a variant of the Koch reaction occurs instead, and formic acid adds to the alkene to produce a larger carboxylic acid. An unstable formic anhydride , H(C=O)−O−(C=O)H, can be obtained by dehydration of formic acid with N , N ′ -dicyclohexylcarbodiimide in ether at low temperature. In 2009, the worldwide capacity for producing formic acid

1716-429: The reaction and no additional acid catalyst is needed. Formic acid shares some of the reducing properties of aldehydes , reducing solutions of metal oxides to their respective metal. Formic acid is a source for a formyl group for example in the formylation of N -methylaniline to N -methylformanilide in toluene . In synthetic organic chemistry , formic acid is often used as a source of hydride ion, as in

1760-455: The resulting fine point pierces the skin. Pressure forces the fluid out of the hair. Different toxins may be involved. The stinging hairs of Tragia spp, notably Tragia volubilis , a South American member of the Euphorbiaceae , are capable of injecting a crystal of calcium oxalate . The stinging sensation is initially caused by the mechanical entry of the stiff hair into the skin, but

1804-487: The surface of the stem or leaf. Some plants have glandular hairs, either as well as non-glandular hairs or instead of them. Glandular hairs have regions of tissue that produce secretions of secondary metabolites. These chemical substances can repel or poison feeding insects. Stinging hairs may be defined as those with ability to inject a chemical substance through the skin of an animal causing irritation or pain. Since some glandular hairs can cause irritation merely by contact,

List of plants known as nettle - Misplaced Pages Continue

1848-578: Was 720 thousand tonnes (1.6 billion pounds) per year, roughly equally divided between Europe (350 thousand tonnes or 770 million pounds, mainly in Germany) and Asia (370 thousand tonnes or 820 million pounds, mainly in China) while production was below 1 thousand tonnes or 2.2 million pounds per year in all other continents. It is commercially available in solutions of various concentrations between 85 and 99 w/w %. As of 2009 ,

1892-453: Was attributed to oxalic and tartaric acid , although a synergistic effect of the other components of the stinging hairs was not ruled out. Fu et al. concluded that "stinging hairs, although studied for a long time, are still mysterious, particularly concerning the mechanism of the skin reaction after being stung." Many plants with stinging hairs belong to the genus Urtica . Between twenty-four and thirty-nine species of flowering plants of

1936-565: Was first synthesized from hydrocyanic acid by the French chemist Joseph Gay-Lussac . In 1855, another French chemist, Marcellin Berthelot , developed a synthesis from carbon monoxide similar to the process used today. Formic acid was long considered a chemical compound of only minor interest in the chemical industry. In the late 1960s, significant quantities became available as a byproduct of acetic acid production. It now finds increasing use as

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