Misplaced Pages

#622377

73-444: Ethylvanillin is the organic compound with the formula (C 2 H 5 O)(HO)C 6 H 3 CHO. This colorless solid consists of a benzene ring with hydroxyl , ethoxy, and formyl groups on the 4, 3, and 1 positions, respectively. It is a homologue of vanillin , differing on the 3 position. Ethylvanillin is prepared from catechol , beginning with ethylation to give guaethol ( 1 ). This ether condenses with glyoxylic acid to give

146-472: A honeycomb lattice with a bond length of 0.142 nm, and the distance between planes is 0.335 nm. Bonding between layers is relatively weak van der Waals bonds , which allows the graphene-like layers to be easily separated and to glide past each other. Electrical conductivity perpendicular to the layers is consequently about 1000 times lower. There are two allotropic forms called alpha ( hexagonal ) and beta ( rhombohedral ), differing in terms of

219-462: A fluidized bed at 1000–1300 °C then it is isotropic turbostratic, and is used in blood-contacting devices like mechanical heart valves and is called pyrolytic carbon , and is not diamagnetic. Pyrolytic graphite and pyrolytic carbon are often confused but are very different materials. ) For a long time graphite has been considered to be hydrophobic. However, recent studies using highly ordered pyrolytic graphite have shown that freshly clean graphite

292-454: A gear lubricant for mining machinery, and to lubricate locks. Having low-grit graphite, or even better, no-grit graphite (ultra high purity), is highly desirable. It can be used as a dry powder, in water or oil, or as colloidal graphite (a permanent suspension in a liquid). An estimate based on USGS graphite consumption statistics indicates that 2,200 tonnes were used in this fashion in 2005. Metal can also be impregnated into graphite to create

365-523: A growth in demand for graphite in the late 1980s and early 1990s – a growth driven by portable electronics, such as portable CD players and power tools . Laptops , mobile phones , tablets , and smartphone products have increased the demand for batteries. Electric-vehicle batteries are anticipated to increase graphite demand. As an example, a lithium-ion battery in a fully electric Nissan Leaf contains nearly 40 kg of graphite. Radioactive graphite removed from nuclear reactors has been investigated as

438-431: A ladle or red-hot steel ingots and decrease heat loss, or as firestops fitted around a fire door or in sheet metal collars surrounding plastic pipe (during a fire, the graphite expands and chars to resist fire penetration and spread), or to make high-performance gasket material for high-temperature use. After being made into graphite foil, the foil is machined and assembled into the bipolar plates in fuel cells . The foil

511-646: A processing plant there, and a factory to manufacture pencils, crucibles and other products in New Jersey, described in the Engineering & Mining Journal 21 December 1878. The Dixon pencil is still in production. The beginnings of the revolutionary froth flotation process are associated with graphite mining. Included in the E&;MJ article on the Dixon Crucible Company is a sketch of

584-474: A regulative force must exist within living bodies. Berzelius also contended that compounds could be distinguished by whether they required any organisms in their synthesis (organic compounds) or whether they did not ( inorganic compounds ). Vitalism taught that formation of these "organic" compounds were fundamentally different from the "inorganic" compounds that could be obtained from the elements by chemical manipulations in laboratories. Vitalism survived for

657-509: A result of the reduction of sedimentary carbon compounds during metamorphism . It also occurs in igneous rocks and in meteorites . Minerals associated with graphite include quartz , calcite , micas and tourmaline . The principal export sources of mined graphite are in order of tonnage: China , Mexico , Canada , Brazil , and Madagascar . Significant unexploited graphite resources also exists in Colombia 's Cordillera Central in

730-535: A self-lubricating alloy for application in extreme conditions, such as bearings for machines exposed to high or low temperatures. The ability to leave marks on paper and other objects gave graphite its name, given in 1789 by German mineralogist Abraham Gottlob Werner . It stems from γράφειν ("graphein") , meaning to write or draw in Ancient Greek . From the 16th century, all pencils were made with leads of English natural graphite, but modern pencil lead

803-452: A short period after the formulation of modern ideas about the atomic theory and chemical elements . It first came under question in 1824, when Friedrich Wöhler synthesized oxalic acid , a compound known to occur only in living organisms, from cyanogen . A further experiment was Wöhler's 1828 synthesis of urea from the inorganic salts potassium cyanate and ammonium sulfate . Urea had long been considered an "organic" compound, as it

SECTION 10

#1732798546623

876-404: A single element and so not generally considered chemical compounds . The word "organic" in this context does not mean "natural". Vitalism was a widespread conception that substances found in organic nature are formed from the chemical elements by the action of a "vital force" or "life-force" ( vis vitalis ) that only living organisms possess. In the 1810s, Jöns Jacob Berzelius argued that

949-436: A small but significant market for natural graphite. Around 7% of the 1.1 million tonnes produced in 2011 was used to make pencils. Low-quality amorphous graphite is used and sourced mainly from China. In art, graphite is typically used to create detailed and precise drawings, as it allows for a wide range of values (light to dark) to be achieved. It can also be used to create softer, more subtle lines and shading. Graphite

1022-634: A small percentage of Earth's crust , they are of central importance because all known life is based on organic compounds. Living things incorporate inorganic carbon compounds into organic compounds through a network of processes ( the carbon cycle ) that begins with the conversion of carbon dioxide and a hydrogen source like water into simple sugars and other organic molecules by autotrophic organisms using light ( photosynthesis ) or other sources of energy. Most synthetically-produced organic compounds are ultimately derived from petrochemicals consisting mainly of hydrocarbons , which are themselves formed from

1095-433: A source of electricity for low-power applications. This waste is rich in carbon-14 , which emits electrons through beta decay , so it could potentially be used as the basis for a betavoltaic device . This concept is known as the diamond battery . Graphite is 'predominant anode material used today in lithium-ion batteries'. EV batteries contain four basic components: anode, cathode, electrolyte, and separator. While there

1168-421: A transition metal and to oxygen, and are often prepared directly from metal and carbon monoxide . Nickel tetracarbonyl is typically classified as an organometallic compound as it satisfies the broad definition that organometallic chemistry covers all compounds that contain at least one carbon to metal covalent bond; it is unknown whether organometallic compounds form a subset of organic compounds. For example,

1241-1692: A variety of ways. One major distinction is between natural and synthetic compounds. Organic compounds can also be classified or subdivided by the presence of heteroatoms , e.g., organometallic compounds , which feature bonds between carbon and a metal , and organophosphorus compounds , which feature bonds between carbon and a phosphorus . Another distinction, based on the size of organic compounds, distinguishes between small molecules and polymers . Natural compounds refer to those that are produced by plants or animals. Many of these are still extracted from natural sources because they would be more expensive to produce artificially. Examples include most sugars , some alkaloids and terpenoids , certain nutrients such as vitamin B 12 , and, in general, those natural products with large or stereoisometrically complicated molecules present in reasonable concentrations in living organisms. Further compounds of prime importance in biochemistry are antigens , carbohydrates , enzymes , hormones , lipids and fatty acids , neurotransmitters , nucleic acids , proteins , peptides and amino acids , lectins , vitamins , and fats and oils . Compounds that are prepared by reaction of other compounds are known as " synthetic ". They may be either compounds that are already found in plants/animals or those artificial compounds that do not occur naturally . Most polymers (a category that includes all plastics and rubbers ) are organic synthetic or semi-synthetic compounds. Many organic compounds—two examples are ethanol and insulin —are manufactured industrially using organisms such as bacteria and yeast. Typically,

1314-964: Is a crystalline allotrope (form) of the element carbon . It consists of many stacked layers of graphene , typically in the excess of hundreds of layers. Graphite occurs naturally and is the most stable form of carbon under standard conditions . Synthetic and natural graphite are consumed on a large scale (1.3   million metric tons per year in 2022) for uses in many critical industries including refractories (50%), lithium-ion batteries (18%), foundries (10%), lubricants (5%), among others (17%). Under extremely high pressures and extremely high temperatures it converts to diamond . Graphite's low cost, thermal and chemical inertness and characteristic conductivity of heat and electricity finds numerous applications in high energy and high temperature processes. Graphite occurs naturally in ores that can be classified into one of two categories either amorphous (microcrystalline) or crystalline (flake or lump/chip) which

1387-630: Is a commercial product proposal for reducing the carbon footprint of lithium iron phosphate (LFP) batteries . It is produced from forestry waste and similar byproducts by a company in New Zealand using a novel process called thermo-catalytic graphitisation which project is supported by grants from interested parties including a forestry company in Finland and a battery maker in Hong Kong Graphite occurs in metamorphic rocks as

1460-738: Is added to increase the carbon content of the steel to a specified level. An estimate based on USGS 's graphite consumption statistics indicates that steelmakers in the US used 10,500 tonnes in this fashion in 2005. Natural amorphous and fine flake graphite are used in brake linings or brake shoes for heavier (nonautomotive) vehicles, and became important with the need to substitute for asbestos . This use has been important for quite some time, but nonasbestos organic (NAO) compositions are beginning to reduce graphite's market share. A brake-lining industry shake-out with some plant closures has not been beneficial, nor has an indifferent automotive market. According to

1533-627: Is an electrical conductor , hence useful in such applications as arc lamp electrodes . It can conduct electricity due to the vast electron delocalization within the carbon layers (a phenomenon called aromaticity ). These valence electrons are free to move, so are able to conduct electricity. However, the electricity is primarily conducted within the plane of the layers. The conductive properties of powdered graphite allow its use as pressure sensor in carbon microphones . Graphite and graphite powder are valued in industrial applications for their self-lubricating and dry lubricating properties. However,

SECTION 20

#1732798546623

1606-972: Is any compound that contains a significant amount of carbon—even though many of the organic compounds known today have no connection to any substance found in living organisms. The term carbogenic has been proposed by E. J. Corey as a modern alternative to organic , but this neologism remains relatively obscure. The organic compound L -isoleucine molecule presents some features typical of organic compounds: carbon–carbon bonds , carbon–hydrogen bonds , as well as covalent bonds from carbon to oxygen and to nitrogen. As described in detail below, any definition of organic compound that uses simple, broadly-applicable criteria turns out to be unsatisfactory, to varying degrees. The modern, commonly accepted definition of organic compound essentially amounts to any carbon-containing compound, excluding several classes of substances traditionally considered "inorganic". The list of substances so excluded varies from author to author. Still, it

1679-439: Is determined by the ore morphology , crystallinity , and grain size . All naturally occurring graphite deposits are formed from the metamorphism of carbonaceous sedimentary rocks , and the ore type is due to its geologic setting. Coal that has been thermally metamorphosed is the typical source of amorphous graphite. Crystalline flake graphite is mined from carbonaceous metamorphic rocks , while lump or chip graphite

1752-710: Is generally agreed upon that there are (at least) a few carbon-containing compounds that should not be considered organic. For instance, almost all authorities would require the exclusion of alloys that contain carbon, including steel (which contains cementite , Fe 3 C ), as well as other metal and semimetal carbides (including "ionic" carbides, e.g, Al 4 C 3 and CaC 2 and "covalent" carbides, e.g. B 4 C and SiC , and graphite intercalation compounds, e.g. KC 8 ). Other compounds and materials that are considered 'inorganic' by most authorities include: metal carbonates , simple oxides of carbon ( CO , CO 2 , and arguably, C 3 O 2 ),

1825-428: Is hydrophilic ( contact angle of 70° approximately), and it becomes hydrophobic (contact angle of 95° approximately) due to airborne pollutants (hydrocarbons) present in the atmosphere. Those contaminants also alter the electric equipotential surface of graphite by creating domains with potential differences of up to 200 mV as measured with kelvin probe force microscopy . Such contaminants can be desorbed by increasing

1898-512: Is made into heat sinks for laptop computers which keeps them cool while saving weight, and is made into a foil laminate that can be used in valve packings or made into gaskets. Old-style packings are now a minor member of this grouping: fine flake graphite in oils or greases for uses requiring heat resistance. A GAN estimate of current US natural graphite consumption in this end-use is 7,500 tonnes. Graphite forms intercalation compounds with some metals and small molecules. In these compounds,

1971-487: Is mined from veins which occur in high-grade metamorphic regions. There are serious negative environmental impacts to graphite mining. Synthetic graphite is graphite of high purity produced by thermal graphitization at temperatures in excess of 2,100 °C from hydrocarbon materials most commonly by a process known as the Acheson process . The high temperatures are maintained for weeks, and are required not only to form

2044-488: Is most commonly a mix of powdered graphite and clay; it was invented by Nicolas-Jacques Conté in 1795. It is chemically unrelated to the metal lead , whose ores had a similar appearance, hence the continuation of the name. Plumbago is another older term for natural graphite used for drawing , typically as a lump of the mineral without a wood casing. The term plumbago drawing is normally restricted to 17th and 18th-century works, mostly portraits. Today, pencils are still

2117-481: Is much focus on the cathode materials – lithium, nickel, cobalt, manganese, etc. – the predominant anode material used in virtually all EV batteries is graphite. Natural graphite in steelmaking mostly goes into raising the carbon content in molten steel; it can also serve to lubricate the dies used to extrude hot steel. Carbon additives face competitive pricing from alternatives such as synthetic graphite powder, petroleum coke, and other forms of carbon. A carbon raiser

2190-448: Is now a minor part of refractories . In the mid-1980s, the carbon- magnesite brick became important, and a bit later the alumina-graphite shape. As of 2017 the order of importance is: alumina-graphite shapes, carbon-magnesite brick, Monolithics (gunning and ramming mixes), and then crucibles. Crucibles began using very large flake graphite, and carbon-magnesite bricks requiring not quite so large flake graphite; for these and others there

2263-452: Is now much more flexibility in the size of flake required, and amorphous graphite is no longer restricted to low-end refractories. Alumina-graphite shapes are used as continuous casting ware, such as nozzles and troughs, to convey the molten steel from ladle to mold, and carbon magnesite bricks line steel converters and electric-arc furnaces to withstand extreme temperatures. Graphite blocks are also used in parts of blast furnace linings where

Ethylvanillin - Misplaced Pages Continue

2336-479: Is on a carbon atom. For historical reasons discussed below, a few types of carbon-containing compounds, such as carbides , carbonates (excluding carbonate esters ), simple oxides of carbon (for example, CO and CO 2 ) and cyanides are generally considered inorganic compounds . Different forms ( allotropes ) of pure carbon, such as diamond , graphite , fullerenes and carbon nanotubes are also excluded because they are simple substances composed of

2409-438: Is popular among artists because it is easy to control, easy to erase, and produces a clean, professional look. It is also relatively inexpensive and widely available. Many artists use graphite in conjunction with other media, such as charcoal or ink, to create a range of effects and textures in their work. Graphite of various hardness or softness results in different qualities and tones when used as an artistic medium . Graphite

2482-404: Is probably the most-used lubricant in pinewood derbies . Natural graphite has found uses in zinc-carbon batteries , electric motor brushes, and various specialized applications. Railroads would often mix powdered graphite with waste oil or linseed oil to create a heat-resistant protective coating for the exposed portions of a steam locomotive's boiler, such as the smokebox or lower part of

2555-464: Is what makes it the dominant anode material in lithium-ion batteries. In 1893, Charles Street of Le Carbone discovered a process for making artificial graphite. In the mid-1890s, Edward Goodrich Acheson (1856–1931) accidentally invented another way to produce synthetic graphite after synthesizing carborundum (also called silicon carbide). He discovered that overheating carborundum, as opposed to pure carbon, produced almost pure graphite. While studying

2628-551: The DNA of an organism is altered to express compounds not ordinarily produced by the organism. Many such biotechnology -engineered compounds did not previously exist in nature. A great number of more specialized databases exist for diverse branches of organic chemistry. The main tools are proton and carbon-13 NMR spectroscopy , IR Spectroscopy , Mass spectrometry , UV/Vis Spectroscopy and X-ray crystallography . Graphite Graphite ( / ˈ ɡ r æ f aɪ t / )

2701-527: The USGS , US natural graphite consumption in brake linings was 6,510 tonnes in 2005. A foundry-facing mold wash is a water-based paint of amorphous or fine flake graphite. Painting the inside of a mold with it and letting it dry leaves a fine graphite coat that will ease the separation of the object cast after the hot metal has cooled. Graphite lubricants are specialty items for use at very high or very low temperatures, as forging die lubricant, an antiseize agent,

2774-781: The allotropes of carbon, cyanide derivatives not containing an organic residue (e.g., KCN , (CN) 2 , BrCN , cyanate anion OCN , etc.), and heavier analogs thereof (e.g., cyaphide anion CP , CSe 2 , COS ; although carbon disulfide CS 2 is often classed as an organic solvent). Halides of carbon without hydrogen (e.g., CF 4 and CClF 3 ), phosgene ( COCl 2 ), carboranes , metal carbonyls (e.g., nickel tetracarbonyl ), mellitic anhydride ( C 12 O 9 ), and other exotic oxocarbons are also considered inorganic by some authorities. Nickel tetracarbonyl ( Ni(CO) 4 ) and other metal carbonyls are often volatile liquids, like many organic compounds, yet they contain only carbon bonded to

2847-415: The firebox . The Scope soldering iron uses a graphite tip as its heating element. Expanded graphite is made by immersing natural flake graphite in a bath of chromic acid , then concentrated sulfuric acid , which forces the crystal lattice planes apart, thus expanding the graphite. The expanded graphite can be used to make graphite foil or used directly as a "hot top" compound to insulate molten metal in

2920-414: The "floating tanks" used in the age-old process of extracting graphite. Because graphite is so light, the mix of graphite and waste was sent through a final series of water tanks where a cleaner graphite "floated" off, which left waste to drop out. In an 1877 patent, the two brothers Bessel (Adolph and August) of Dresden, Germany, took this "floating" process a step further and added a small amount of oil to

2993-517: The 100th anniversary of flotation. In the United States, in 1885, Hezekiah Bradford of Philadelphia patented a similar process, but it is uncertain if his process was used successfully in the nearby graphite deposits of Chester County, Pennsylvania, a major producer by the 1890s. The Bessel process was limited in use, primarily because of the abundant cleaner deposits found around the globe, which needed not much more than hand-sorting to gather

Ethylvanillin - Misplaced Pages Continue

3066-546: The English navy. This particular deposit of graphite was extremely pure and soft, and could easily be cut into sticks. Because of its military importance, this unique mine and its production were strictly controlled by the Crown. During the 19th century, graphite's uses greatly expanded to include stove polish, lubricants, paints, crucibles, foundry facings, and pencils , a major factor in the expansion of educational tools during

3139-531: The English term for this grey metallic-sheened mineral and even to the leadworts or plumbagos , plants with flowers that resemble this colour. The term black lead usually refers to a powdered or processed graphite, matte black in color. Abraham Gottlob Werner coined the name graphite ("writing stone") in 1789. He attempted to clear up the confusion between molybdena, plumbago and black lead after Carl Wilhelm Scheele in 1778 proved that these were at least three different minerals. Scheele's analysis showed that

3212-546: The above refractories are used to make steel and account for 75% of refractory consumption; the rest is used by a variety of industries, such as cement. According to the USGS , US natural graphite consumption in refractories comprised 12,500 tonnes in 2010. The use of graphite in batteries has increased since the 1970s. Natural and synthetic graphite are used as an anode material to construct electrodes in major battery technologies. The demand for batteries, primarily nickel–metal hydride and lithium-ion batteries , caused

3285-406: The beta form reverts to the alpha form when it is heated to 1300 °C for four hours. The equilibrium pressure and temperature conditions for a transition between graphite and diamond is well established theoretically and experimentally. The pressure changes linearly between 1.7  GPa at 0 K and 12 GPa at 5000 K (the diamond/graphite/liquid triple point ). However,

3358-434: The chemical compounds molybdenum sulfide ( molybdenite ), lead(II) sulfide ( galena ) and graphite were three different soft black minerals. Natural graphite is mostly used for refractories, batteries, steelmaking, expanded graphite, brake linings, foundry facings, and lubricants. The use of graphite as a refractory (heat-resistant) material began before 1900 with graphite crucibles used to hold molten metal; this

3431-431: The corresponding mandelic acid derivative ( 2 ), which by oxidation ( 3 ) and decarboxylation, gives ethylvanillin ( 4 ). As a flavorant, ethylvanillin is about three times as potent as vanillin and is used in the production of chocolate . The molecule revolutionized both the design and aesthetics of olfactory art ; artist Jacques Guerlain added a large quantity of it to a bottle of Jicky (1889) perfume, creating

3504-576: The discipline known as organic chemistry . For historical reasons, a few classes of carbon-containing compounds (e.g., carbonate salts and cyanide salts ), along with a few other exceptions (e.g., carbon dioxide , and even hydrogen cyanide despite the fact it contains a carbon-hydrogen bond), are generally considered inorganic . Other than those just named, little consensus exists among chemists on precisely which carbon-containing compounds are excluded, making any rigorous definition of an organic compound elusive. Although organic compounds make up only

3577-462: The effects of high temperature on carborundum, he had found that silicon vaporizes at about 4,150 °C (7,500 °F), leaving the carbon behind in graphitic carbon. This graphite became valuable as a lubricant. Acheson's technique for producing silicon carbide and graphite is named the Acheson process . In 1896, Acheson received a patent for his method of synthesizing graphite, and in 1897 started commercial production. The Acheson Graphite Co.

3650-480: The ejecta when supernovae exploded or low to intermediate-sized stars expelled their outer envelopes late in their lives. Graphite may be the second or third oldest mineral in the Universe. Graphite consists of sheets of trigonal planar carbon. The individual layers are called graphene . In each layer, each carbon atom is bonded to three other atoms forming a continuous layer of sp bonded carbon hexagons, like

3723-613: The equilibrium line: at 2000 K , a pressure of 35 GPa is needed. The acoustic and thermal properties of graphite are highly anisotropic , since phonons propagate quickly along the tightly bound planes, but are slower to travel from one plane to another. Graphite's high thermal stability and electrical and thermal conductivity facilitate its widespread use as electrodes and refractories in high temperature material processing applications. However, in oxygen-containing atmospheres graphite readily oxidizes to form carbon dioxide at temperatures of 700 °C and above. Graphite

SECTION 50

#1732798546623

3796-938: The evidence of covalent Fe-C bonding in cementite , a major component of steel, places it within this broad definition of organometallic, yet steel and other carbon-containing alloys are seldom regarded as organic compounds. Thus, it is unclear whether the definition of organometallic should be narrowed, whether these considerations imply that organometallic compounds are not necessarily organic, or both. Metal complexes with organic ligands but no carbon-metal bonds (e.g., (CH 3 CO 2 ) 2 Cu ) are not considered organometallic; instead, they are called metal-organic compounds (and might be considered organic). The relatively narrow definition of organic compounds as those containing C-H bonds excludes compounds that are (historically and practically) considered organic. Neither urea CO(NH 2 ) 2 nor oxalic acid (COOH) 2 are organic by this definition, yet they were two key compounds in

3869-490: The first great rise of education for the masses. The British Empire controlled most of the world's production (especially from Ceylon), but production from Austrian, German, and American deposits expanded by mid-century. For example, the Dixon Crucible Company of Jersey City, New Jersey, founded by Joseph Dixon and partner Orestes Cleveland in 1845, opened mines in the Lake Ticonderoga district of New York, built

3942-598: The form of graphite-bearing schists . In meteorites , graphite occurs with troilite and silicate minerals . Small graphitic crystals in meteoritic iron are called cliftonite . Some microscopic grains have distinctive isotopic compositions, indicating that they were formed before the Solar System . They are one of about 12 known types of minerals that predate the Solar System and have also been detected in molecular clouds . These minerals were formed in

4015-800: The graphite from the precursor carbons but to also vaporize any impurities that may be present, including hydrogen, nitrogen, sulfur, organics, and metals. This is why synthetic graphite is highly pure in excess of 99.9% C purity, but typically has lower density, conductivity and a higher porosity than its natural equivalent. Synthetic graphite can also be formed into very large flakes (cm) while maintaining its high purity unlike almost all sources of natural graphite. Synthetic graphite has also been known to be formed by other methods including by chemical vapor deposition from hydrocarbons at temperatures above 2,500 K (2,230 °C), by decomposition of thermally unstable carbides or by crystallizing from metal melts supersaturated with carbon . Biographite

4088-404: The high pressure and temperature degradation of organic matter underground over geological timescales. This ultimate derivation notwithstanding, organic compounds are no longer defined as compounds originating in living things, as they were historically. In chemical nomenclature, an organyl group , frequently represented by the letter R, refers to any monovalent substituent whose open valence

4161-460: The high thermal conductivity of the graphite is critical to ensuring adequate cooling of the bottom and hearth of the furnace. High-purity monolithics are often used as a continuous furnace lining instead of carbon-magnesite bricks. The US and European refractories industry had a crisis in 2000–2003, with an indifferent market for steel and a declining refractory consumption per tonne of steel underlying firm buyouts and many plant closures. Many of

4234-612: The host molecule or atom gets "sandwiched" between the graphite layers, resulting in a type of compound with variable stoichiometry. A prominent example of an intercalation compound is potassium graphite, denoted by the formula KC 8 . Some graphite intercalation compounds are superconductors . The highest transition temperature (by June 2009) T c = 11.5 K is achieved in CaC 6 , and it further increases under applied pressure (15.1 K at 8 GPa). Graphite's ability to intercalate lithium ions without significant damage from swelling

4307-440: The main accord for the perfume house's flagship fragrance, Shalimar (perfume) (1925). This is one of the earliest uses of synthetic molecules that freed scent artists from the limits of natural materials. Organic compound Due to carbon's ability to catenate (form chains with other carbon atoms ), millions of organic compounds are known. The study of the properties, reactions, and syntheses of organic compounds comprise

4380-601: The mineral mellite ( Al 2 C 6 (COO) 6 ·16H 2 O ). A slightly broader definition of the organic compound includes all compounds bearing C-H or C-C bonds. This would still exclude urea. Moreover, this definition still leads to somewhat arbitrary divisions in sets of carbon-halogen compounds. For example, CF 4 and CCl 4 would be considered by this rule to be "inorganic", whereas CHF 3 , CHCl 3 , and C 2 Cl 6 would be organic, though these compounds share many physical and chemical properties. Organic compounds may be classified in

4453-457: The phases have a wide region about this line where they can coexist. At normal temperature and pressure , 20 °C (293 K) and 1 standard atmosphere (0.10 MPa), the stable phase of carbon is graphite, but diamond is metastable and its rate of conversion to graphite is negligible. However, at temperatures above about 4500 K , diamond rapidly converts to graphite. Rapid conversion of graphite to diamond requires pressures well above

SECTION 60

#1732798546623

4526-408: The plant closures resulted from the acquisition of Harbison-Walker Refractories by RHI AG and some plants had their equipment auctioned off. Since much of the lost capacity was for carbon-magnesite brick, graphite consumption within the refractories area moved towards alumina-graphite shapes and Monolithics, and away from the brick. The major source of carbon-magnesite brick is now China. Almost all of

4599-575: The pure graphite. The state of the art, c.  1900 , is described in the Canadian Department of Mines report on graphite mines and mining when Canadian deposits began to become important producers of graphite. Historically, graphite was called black lead or plumbago . Plumbago was commonly used in its massive mineral form. Both of these names arise from confusion with the similar-appearing lead ores, particularly galena . The Latin word for lead, plumbum , gave its name to

4672-405: The same molecular structure as graphite. It is sometimes called white graphite , due to its similar properties. When a large number of crystallographic defects bind these planes together, graphite loses its lubrication properties and becomes what is known as pyrolytic graphite . It is also highly anisotropic, and diamagnetic , thus it will float in mid-air above a strong magnet. (If it is made in

4745-405: The stacking of the graphene layers: stacking in alpha graphite is ABA, as opposed to ABC stacking in the energetically less stable beta graphite. Rhombohedral graphite cannot occur in pure form. Natural graphite, or commercial natural graphite, contains 5 to 15% rhombohedral graphite and this may be due to intensive milling. The alpha form can be converted to the beta form through shear forces, and

4818-592: The tanks and boiled the mix – an agitation or frothing step – to collect the graphite, the first steps toward the future flotation process. Adolph Bessel received the Wohler Medal for the patented process that upgraded the recovery of graphite to 90% from the German deposit. In 1977, the German Society of Mining Engineers and Metallurgists organized a special symposium dedicated to their discovery and, thus,

4891-600: The temperature of graphite to approximately 50 °C or higher. Natural and crystalline graphites are not often used in pure form as structural materials, due to their shear-planes, brittleness, and inconsistent mechanical properties. In the 4th millennium BCE , during the Neolithic Age in southeastern Europe, the Marița culture used graphite in a ceramic paint for decorating pottery . Sometime before 1565 (some sources say as early as 1500), an enormous deposit of graphite

4964-632: The use of graphite is limited by its tendency to facilitate pitting corrosion in some stainless steel , and to promote galvanic corrosion between dissimilar metals (due to its electrical conductivity). It is also corrosive to aluminium in the presence of moisture. For this reason, the US Air Force banned its use as a lubricant in aluminium aircraft, and discouraged its use in aluminium-containing automatic weapons. Even graphite pencil marks on aluminium parts may facilitate corrosion. Another high-temperature lubricant, hexagonal boron nitride , has

5037-484: The vast majority of steel furnaces . They are made from petroleum coke after it is mixed with coal tar pitch . They are extruded and shaped, then baked to carbonize the binder (pitch). This is finally graphitized by heating it to temperatures approaching 3,000 °C (5,430 °F), at which the carbon atoms arrange into graphite. They can vary in size up to 3.5 m (11 ft) long and 75 cm (30 in) in diameter. An increasing proportion of global steel

5110-589: The vitalism debate. However, the IUPAC Blue Book on organic nomenclature specifically mentions urea and oxalic acid as organic compounds. Other compounds lacking C-H bonds but traditionally considered organic include benzenehexol , mesoxalic acid , and carbon tetrachloride . Mellitic acid , which contains no C-H bonds, is considered a possible organic compound in Martian soil. Terrestrially, it, and its anhydride, mellitic anhydride , are associated with

5183-466: Was discovered on the approach to Grey Knotts from the hamlet of Seathwaite in Borrowdale parish , Cumbria , England , which the locals found useful for marking sheep. During the reign of Elizabeth I (1558–1603), Borrowdale graphite was used as a refractory material to line molds for cannonballs, resulting in rounder, smoother balls that could be fired farther, contributing to the strength of

5256-488: Was formed in 1899. Synthetic graphite can also be prepared from polyimide and then commercialized. Highly oriented pyrolytic graphite (HOPG) is the highest-quality synthetic form of graphite. It is used in scientific research, in particular, as a length standard for the calibration of scanning probe microscopes . Graphite electrodes carry the electricity that melts scrap iron and steel, and sometimes direct-reduced iron (DRI), in electric arc furnaces , which are

5329-445: Was known to occur only in the urine of living organisms. Wöhler's experiments were followed by many others, in which increasingly complex "organic" substances were produced from "inorganic" ones without the involvement of any living organism, thus disproving vitalism. Although vitalism has been discredited, scientific nomenclature retains the distinction between organic and inorganic compounds. The modern meaning of organic compound

#622377