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90-507: The range of chemicals studied in organic chemistry includes hydrocarbons (compounds containing only carbon and hydrogen ) as well as compounds based on carbon, but also containing other elements, especially oxygen , nitrogen , sulfur , phosphorus (included in many biochemicals ) and the halogens . Organometallic chemistry is the study of compounds containing carbon– metal bonds. In addition, contemporary research focuses on organic chemistry involving other organometallics including

180-509: A =4), thiols (13), malonates (13), alcohols (17), aldehydes (20), nitriles (25), esters (25), then amines (35). Amines are very basic, and are great nucleophiles/attackers. The aliphatic hydrocarbons are subdivided into three groups of homologous series according to their state of saturation : The rest of the group is classified according to the functional groups present. Such compounds can be "straight-chain", branched-chain or cyclic. The degree of branching affects characteristics, such as

270-722: A molar mass less than approximately 1000 g/mol. Fullerenes and carbon nanotubes , carbon compounds with spheroidal and tubular structures, have stimulated much research into the related field of materials science . The first fullerene was discovered in 1985 by Sir Harold W. Kroto of the United Kingdom and by Richard E. Smalley and Robert F. Curl Jr., of the United States. Using a laser to vaporize graphite rods in an atmosphere of helium gas, these chemists and their assistants obtained cagelike molecules composed of 60 carbon atoms (C60) joined by single and double bonds to form

360-546: A branch of organic chemistry. Although the history of biochemistry might be taken to span some four centuries, fundamental understanding of the field only began to develop in the late 19th century and the actual term biochemistry was coined around the start of 20th century. Research in the field increased throughout the twentieth century, without any indication of slackening in the rate of increase, as may be verified by inspection of abstraction and indexing services such as BIOSIS Previews and Biological Abstracts , which began in

450-423: A broad range of industrial and commercial products including, among (many) others: plastics , synthetic rubber , organic adhesives , and various property-modifying petroleum additives and catalysts . The majority of chemical compounds occurring in biological organisms are carbon compounds, so the association between organic chemistry and biochemistry is so close that biochemistry might be regarded as in essence

540-508: A carbon lattice, and that the detailed patterns of atomic bonding could be discerned by skillful interpretations of appropriate chemical reactions. The era of the pharmaceutical industry began in the last decade of the 19th century when the German company, Bayer , first manufactured acetylsalicylic acid—more commonly known as aspirin . By 1910 Paul Ehrlich and his laboratory group began developing arsenic-based arsphenamine , (Salvarsan), as

630-415: A class of hydrocarbons called biopolymer polyisoprenoids present in the latex of various species of plants, which is the basis for making rubber . Biologists usually classify the above-mentioned biomolecules into four main groups, i.e., proteins, lipids, carbohydrates, and nucleic acids. Petroleum and its derivatives are considered organic molecules, which is consistent with the fact that this oil comes from

720-461: A combination of luck and preparation for unexpected observations. The latter half of the 19th century however witnessed systematic studies of organic compounds. The development of synthetic indigo is illustrative. The production of indigo from plant sources dropped from 19,000 tons in 1897 to 1,000 tons by 1914 thanks to the synthetic methods developed by Adolf von Baeyer . In 2002, 17,000 tons of synthetic indigo were produced from petrochemicals . In

810-414: A common thermoplastic material. Addition reactions apply to alkenes and alkynes. It is because they add reagents that they are called unsaturated. In this reaction a variety of reagents add "across" the pi-bond(s). Chlorine, hydrogen chloride, water , and hydrogen are illustrative reagents. Polymerization is a form of addition. Alkenes and some alkynes also undergo polymerization by opening of

900-419: A common reaction is a substitution reaction written as: where X is some functional group and Nu is a nucleophile . The number of possible organic reactions is infinite. However, certain general patterns are observed that can be used to describe many common or useful reactions. Each reaction has a stepwise reaction mechanism that explains how it happens in sequence—although the detailed description of steps

990-426: A double bond between carbon atoms are sometimes referred to as 'olefins'. The predominant use of hydrocarbons is as a combustible fuel source. Methane is the predominant component of natural gas. C through C alkanes, alkenes, cycloalkanes, and aromatic hydrocarbons are the main components of gasoline , naphtha , jet fuel , and specialized industrial solvent mixtures. With the progressive addition of carbon units,

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1080-422: A former student of Kekulé, who argued that Kekulé's 1865 structure implied two distinct "ortho" structures, depending on whether the substituted carbons are separated by a single or a double bond. Since ortho derivatives of benzene were never actually found in more than one isomeric form, Kekulé modified his proposal in 1872 and suggested that the benzene molecule oscillates between two equivalent structures, in such

1170-576: A hollow sphere with 12 pentagonal and 20 hexagonal faces—a design that resembles a football, or soccer ball. In 1996 the trio was awarded the Nobel Prize for their pioneering efforts. The C60 molecule was named buckminsterfullerene (or, more simply, the buckyball) after the American architect R. Buckminster Fuller, whose geodesic dome is constructed on the same structural principles. Organic compounds containing bonds of carbon to nitrogen, oxygen and

1260-427: A lower p K a on another molecule (intermolecular) or within the same molecule (intramolecular). Any group with a net acidic p K a that gets within range, such as an acyl or carbonyl group is fair game. Since the likelihood of being attacked decreases with an increase in p K a , acyl chloride components with the lowest measured p K a values are most likely to be attacked, followed by carboxylic acids (p K

1350-484: A melting point, boiling point, solubility, and index of refraction. Qualitative properties include odor, consistency, and color. Organic compounds typically melt and many boil. In contrast, while inorganic materials generally can be melted, many do not boil, and instead tend to degrade. In earlier times, the melting point (m.p.) and boiling point (b.p.) provided crucial information on the purity and identity of organic compounds. The melting and boiling points correlate with

1440-475: A novel compound is a problem-solving task, where a synthesis is designed for a target molecule by selecting optimal reactions from optimal starting materials. Complex compounds can have tens of reaction steps that sequentially build the desired molecule. The synthesis proceeds by utilizing the reactivity of the functional groups in the molecule. For example, a carbonyl compound can be used as a nucleophile by converting it into an enolate , or as an electrophile ;

1530-641: A paper in French (for he was then still in Belgium) suggesting that the structure contained a six-membered ring of carbon atoms with alternating single and double bonds. The following year he published a much longer paper in German on the same subject. The empirical formula for benzene had been long known, but its highly unsaturated structure was a challenge to determine. Archibald Scott Couper in 1858 and Joseph Loschmidt in 1861 suggested possible structures that contained multiple double bonds or multiple rings, but

1620-552: A respectfully natural environment, or without human intervention. Biomolecular chemistry is a major category within organic chemistry which is frequently studied by biochemists . Many complex multi-functional group molecules are important in living organisms. Some are long-chain biopolymers , and these include peptides , DNA , RNA and the polysaccharides such as starches in animals and celluloses in plants. The other main classes are amino acids (monomer building blocks of peptides and proteins), carbohydrates (which includes

1710-529: A single C–C bond it is alkane metathesis , for a double C–C bond it is alkene metathesis (olefin metathesis), and for a triple C–C bond it is alkyne metathesis . The vast majority of hydrocarbons found on Earth occur in crude oil , petroleum, coal , and natural gas. Since thousands of years they have been exploited and used for a vast range of purposes. Petroleum ( lit.   ' rock oil ' ) and coal are generally thought to be products of decomposition of organic matter. Coal, in contrast to petroleum,

1800-468: A two neutral radical atoms ( homolytic fission ). all the way to CCl 4 ( carbon tetrachloride ) all the way to C 2 Cl 6 ( hexachloroethane ) Aromatic compounds, almost uniquely for hydrocarbons, undergo substitution reactions. The chemical process practiced on the largest scale is the reaction of benzene and ethene to give ethylbenzene : The resulting ethylbenzene is dehydrogenated to styrene and then polymerized to manufacture polystyrene ,

1890-685: A variety of chemical tests, called "wet methods", but such tests have been largely displaced by spectroscopic or other computer-intensive methods of analysis. Listed in approximate order of utility, the chief analytical methods are: Traditional spectroscopic methods such as infrared spectroscopy , optical rotation , and UV/VIS spectroscopy provide relatively nonspecific structural information but remain in use for specific applications. Refractive index and density can also be important for substance identification. The physical properties of organic compounds typically of interest include both quantitative and qualitative features. Quantitative information includes

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1980-576: A variety of molecules. Functional groups can have a decisive influence on the chemical and physical properties of organic compounds. Molecules are classified based on their functional groups. Alcohols, for example, all have the subunit C-O-H. All alcohols tend to be somewhat hydrophilic , usually form esters , and usually can be converted to the corresponding halides . Most functional groups feature heteroatoms (atoms other than C and H). Organic compounds are classified according to functional groups, alcohols, carboxylic acids, amines, etc. Functional groups make

2070-551: A way that the single and double bonds continually interchange positions. This implies that all six carbon-carbon bonds are equivalent, as each is single half the time and double half the time. A firmer theoretical basis for a similar idea was later proposed in 1928 by Linus Pauling , who replaced Kekulé's oscillation by the concept of resonance between quantum-mechanical structures. The new understanding of benzene, and hence of all aromatic compounds, proved to be so important for both pure and applied chemistry after 1865 that in 1890

2160-514: A wide range of biochemical compounds such as alkaloids , vitamins, steroids, and nucleic acids (e.g. DNA, RNA). Rings can fuse with other rings on an edge to give polycyclic compounds . The purine nucleoside bases are notable polycyclic aromatic heterocycles. Rings can also fuse on a "corner" such that one atom (almost always carbon) has two bonds going to one ring and two to another. Such compounds are termed spiro and are important in several natural products . One important property of carbon

2250-696: Is also potential to harvest hydrocarbons from plants like Euphorbia lathyris and E. tirucalli as an alternative and renewable energy source for vehicles that use diesel. Furthermore, endophytic bacteria from plants that naturally produce hydrocarbons have been used in hydrocarbon degradation in attempts to deplete hydrocarbon concentration in polluted soils. Saturated hydrocarbons are notable for their inertness. Unsaturated hydrocarbons (alkanes, alkenes and aromatic compounds) react more readily, by means of substitution, addition, polymerization. At higher temperatures they undergo dehydrogenation, oxidation and combustion. The cracking of saturated hydrocarbons

2340-400: Is called autoxidation , begins with the formation of hydroperoxides (ROOH). Combustion of hydrocarbons is currently the main source of the world's energy for electric power generation , heating (such as home heating), and transportation. Often this energy is used directly as heat such as in home heaters, which use either petroleum or natural gas . The hydrocarbon is burnt and the heat

2430-420: Is conferred by the presence of 4n + 2 delocalized pi electrons, where n is an integer. Particular instability ( antiaromaticity ) is conferred by the presence of 4n conjugated pi electrons. The characteristics of the cyclic hydrocarbons are again altered if heteroatoms are present, which can exist as either substituents attached externally to the ring (exocyclic) or as a member of the ring itself (endocyclic). In

2520-482: Is estimated at more than 58 million metric tons, which will increase to 60 million tons in 2022. Hydrocarbons are also prevalent in nature. Some eusocial arthropods, such as the Brazilian stingless bee, Schwarziana quadripunctata , use unique cuticular hydrocarbon "scents" in order to determine kin from non-kin. This hydrocarbon composition varies between age, sex, nest location, and hierarchal position. There

2610-479: Is not always clear from a list of reactants alone. The stepwise course of any given reaction mechanism can be represented using arrow pushing techniques in which curved arrows are used to track the movement of electrons as starting materials transition through intermediates to final products. Synthetic organic chemistry is an applied science as it borders engineering , the "design, analysis, and/or construction of works for practical purposes". Organic synthesis of

2700-645: Is possible. Hydrocarbons are generally of low toxicity, hence the widespread use of gasoline and related volatile products. Aromatic compounds such as benzene and toluene are narcotic and chronic toxins, and benzene in particular is known to be carcinogenic . Certain rare polycyclic aromatic compounds are carcinogenic. Hydrocarbons are highly flammable . Friedrich August Kekul%C3%A9 Friedrich August Kekulé , later Friedrich August Kekule von Stradonitz ( / ˈ k eɪ k əl eɪ / KAY -kə-lay , German: [ˈfʁiːdʁɪç ˈʔaʊɡʊst ˈkeːkuleː fɔn ʃtʁaˈdoːnɪts] ; 7 September 1829 – 13 July 1896),

2790-463: Is richer in carbon and poorer in hydrogen. Natural gas is the product of methanogenesis . A seemingly limitless variety of compounds comprise petroleum, hence the necessity of refineries. These hydrocarbons consist of saturated hydrocarbons, aromatic hydrocarbons, or combinations of the two. Missing in petroleum are alkenes and alkynes. Their production requires refineries. Petroleum-derived hydrocarbons are mainly consumed for fuel, but they are also

Organic chemistry - Misplaced Pages Continue

2880-444: Is simple and unambiguous. In this system, the endpoints and intersections of each line represent one carbon, and hydrogen atoms can either be notated explicitly or assumed to be present as implied by tetravalent carbon. By 1880 an explosion in the number of chemical compounds being discovered occurred assisted by new synthetic and analytical techniques. Grignard described the situation as "chaos le plus complet" (complete chaos) due to

2970-451: Is systematically named (6a R ,9 R )- N , N -diethyl-7-methyl-4,6,6a,7,8,9-hexahydroindolo-[4,3- fg ] quinoline-9-carboxamide. With the increased use of computing, other naming methods have evolved that are intended to be interpreted by machines. Two popular formats are SMILES and InChI . Organic molecules are described more commonly by drawings or structural formulas , combinations of drawings and chemical symbols. The line-angle formula

3060-455: Is that it readily forms chains, or networks, that are linked by carbon-carbon (carbon-to-carbon) bonds. The linking process is called polymerization , while the chains, or networks, are called polymers . The source compound is called a monomer . Two main groups of polymers exist synthetic polymers and biopolymers . Synthetic polymers are artificially manufactured, and are commonly referred to as industrial polymers . Biopolymers occur within

3150-616: Is the main industrial route to alkenes and alkyne . These reactions require heterogeneous catalysts and temperatures >500 °C. Widely practice conversions of hydrocarbons involves their reaction with oxygen. In the presence of excess oxygen, hydrocarbons combust. With, however, careful conditions, which have been optimized for many years, partial oxidation results. Useful compounds can obtained in this way: maleic acid from butane , terephthalic acid from xylenes , acetone together with phenol from cumene (isopropylbenzene), and cyclohexanone from cyclohexane]]. The process, which

3240-757: Is the main source of the world's energy. Petroleum is the dominant raw-material source for organic commodity chemicals such as solvents and polymers. Most anthropogenic (human-generated) emissions of greenhouse gases are either carbon dioxide released by the burning of fossil fuels , or methane released from the handling of natural gas or from agriculture. As defined by the International Union of Pure and Applied Chemistry 's nomenclature of organic chemistry , hydrocarbons are classified as follows: The term 'aliphatic' refers to non-aromatic hydrocarbons. Saturated aliphatic hydrocarbons are sometimes referred to as 'paraffins'. Aliphatic hydrocarbons containing

3330-398: Is the paucity of enzymes that act on them. Nonetheless, the area has received regular attention. Bacteria in the gabbroic layer of the ocean's crust can degrade hydrocarbons; but the extreme environment makes research difficult. Other bacteria such as Lutibacterium anuloederans can also degrade hydrocarbons. Mycoremediation or breaking down of hydrocarbon by mycelium and mushrooms

3420-411: Is typically taught at the college or university level. It is considered a very challenging course, but has also been made accessible to students. Before the 18th century, chemists generally believed that compounds obtained from living organisms were endowed with a vital force that distinguished them from inorganic compounds . According to the concept of vitalism (vital force theory), organic matter

3510-597: Is used to heat water, which is then circulated. A similar principle is used to create electrical energy in power plants . Both saturated and unsaturated hydrocarbons undergo this process. Common properties of hydrocarbons are the facts that they produce steam, carbon dioxide and heat during combustion and that oxygen is required for combustion to take place. The simplest hydrocarbon, methane , burns as follows: In inadequate supply of air, carbon black and water vapour are formed: And finally, for any linear alkane of n carbon atoms, Partial oxidation characterizes

3600-563: Is usually faint, and may be similar to that of gasoline or lighter fluid . They occur in a diverse range of molecular structures and phases: they can be gases (such as methane and propane ), liquids (such as hexane and benzene ), low melting solids (such as paraffin wax and naphthalene ) or polymers (such as polyethylene and polystyrene ). In the fossil fuel industries, hydrocarbon refers to naturally occurring petroleum , natural gas and coal , or their hydrocarbon derivatives and purified forms. Combustion of hydrocarbons

3690-694: The Berichte der Durstigen Chemischen Gesellschaft (Journal of the Thirsty Chemical Society), a parody of the Berichte der Deutschen Chemischen Gesellschaft , only the parody had six monkeys seizing each other in a circle, rather than a single snake as in Kekulé's anecdote. Some historians have suggested that the parody was a lampoon of the snake anecdote, possibly already well-known through oral transmission even if it had not yet appeared in print. Others have speculated that Kekulé's story in 1890

Organic chemistry - Misplaced Pages Continue

3780-980: The Grand Duchy of Hesse . After graduating from secondary school (the Grand Ducal Gymnasium in Darmstadt), in the fall of 1847 he entered the University of Giessen , with the intention of studying architecture. After hearing the lectures of Justus von Liebig in his first semester, he decided to study chemistry. Following four years of study in Giessen and a brief compulsory military service, he took temporary assistantships in Paris (1851–52), in Chur , Switzerland (1852–53), and in London (1853–55), where he

3870-541: The Solar System . Lakes of liquid methane and ethane have been found on Titan , Saturn 's largest moon, as confirmed by the Cassini–Huygens space probe. Hydrocarbons are also abundant in nebulae forming polycyclic aromatic hydrocarbon compounds. Burning hydrocarbons as fuel, which produces carbon dioxide and water , is a major contributor to anthropogenic global warming . Hydrocarbons are introduced into

3960-435: The cycloalkenes and the cycloalkynes do. Aromatic hydrocarbons contain conjugated double bonds. This means that every carbon atom in the ring is sp2 hybridized, allowing for added stability. The most important example is benzene , the structure of which was formulated by Kekulé who first proposed the delocalization or resonance principle for explaining its structure. For "conventional" cyclic compounds, aromaticity

4050-419: The electron affinity of key atoms, bond strengths and steric hindrance . These factors can determine the relative stability of short-lived reactive intermediates , which usually directly determine the path of the reaction. The basic reaction types are: addition reactions , elimination reactions , substitution reactions , pericyclic reactions , rearrangement reactions and redox reactions . An example of

4140-483: The lanthanides , but especially the transition metals zinc, copper, palladium , nickel, cobalt, titanium and chromium. Organic compounds form the basis of all earthly life and constitute the majority of known chemicals. The bonding patterns of carbon, with its valence of four—formal single, double, and triple bonds, plus structures with delocalized electrons —make the array of organic compounds structurally diverse, and their range of applications enormous. They form

4230-541: The octane number or cetane number in petroleum chemistry. Both saturated ( alicyclic ) compounds and unsaturated compounds exist as cyclic derivatives. The most stable rings contain five or six carbon atoms, but large rings (macrocycles) and smaller rings are common. The smallest cycloalkane family is the three-membered cyclopropane ((CH 2 ) 3 ). Saturated cyclic compounds contain single bonds only, whereas aromatic rings have an alternating (or conjugated) double bond. Cycloalkanes do not contain multiple bonds, whereas

4320-617: The 1920s as a single annual volume, but has grown so drastically that by the end of the 20th century it was only available to the everyday user as an online electronic database . Since organic compounds often exist as mixtures , a variety of techniques have also been developed to assess purity; chromatography techniques are especially important for this application, and include HPLC and gas chromatography . Traditional methods of separation include distillation , crystallization , evaporation , magnetic separation and solvent extraction . Organic compounds were traditionally characterized by

4410-524: The German Chemical Society organized an elaborate appreciation in Kekulé's honor, celebrating the twenty-fifth anniversary of his first benzene paper. Here Kekulé spoke of the creation of the theory. He said that he had discovered the ring shape of the benzene molecule after having a reverie or day-dream of a snake seizing its own tail (this is an ancient symbol known as the ouroboros ). Another depiction of benzene had appeared in 1886 in

4500-421: The basis of, or are constituents of, many commercial products including pharmaceuticals ; petrochemicals and agrichemicals , and products made from them including lubricants , solvents ; plastics ; fuels and explosives . The study of organic chemistry overlaps organometallic chemistry and biochemistry , but also with medicinal chemistry , polymer chemistry , and materials science . Organic chemistry

4590-495: The case of the latter, the ring is termed a heterocycle . Pyridine and furan are examples of aromatic heterocycles while piperidine and tetrahydrofuran are the corresponding alicyclic heterocycles. The heteroatom of heterocyclic molecules is generally oxygen, sulfur, or nitrogen, with the latter being particularly common in biochemical systems. Heterocycles are commonly found in a wide range of products including aniline dyes and medicines. Additionally, they are prevalent in

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4680-472: The combination of the two is called the aldol reaction . Designing practically useful syntheses always requires conducting the actual synthesis in the laboratory. The scientific practice of creating novel synthetic routes for complex molecules is called total synthesis . Strategies to design a synthesis include retrosynthesis , popularized by E.J. Corey , which starts with the target molecule and splices it to pieces according to known reactions. The pieces, or

4770-480: The early part of the 20th century, polymers and enzymes were shown to be large organic molecules, and petroleum was shown to be of biological origin. The multiple-step synthesis of complex organic compounds is called total synthesis. Total synthesis of complex natural compounds increased in complexity to glucose and terpineol . For example, cholesterol -related compounds have opened ways to synthesize complex human hormones and their modified derivatives. Since

4860-524: The environment through their extensive use as fuels and chemicals as well as through leaks or accidental spills during exploration, production, refining, or transport of fossil fuels. Anthropogenic hydrocarbon contamination of soil is a serious global issue due to contaminant persistence and the negative impact on human health. When soil is contaminated by hydrocarbons, it can have a significant impact on its microbiological, chemical, and physical properties. This can serve to prevent, slow down or even accelerate

4950-426: The first effective medicinal treatment of syphilis , and thereby initiated the medical practice of chemotherapy . Ehrlich popularized the concepts of "magic bullet" drugs and of systematically improving drug therapies. His laboratory made decisive contributions to developing antiserum for diphtheria and standardizing therapeutic serums. Early examples of organic reactions and applications were often found because of

5040-421: The fossilization of living beings, i.e., biomolecules. See also: peptide synthesis , oligonucleotide synthesis and carbohydrate synthesis . In pharmacology, an important group of organic compounds is small molecules , also referred to as 'small organic compounds'. In this context, a small molecule is a small organic compound that is biologically active but is not a polymer . In practice, small molecules have

5130-437: The functional group have an intermolecular and intramolecular effect on the surrounding environment and pH level. Different functional groups have different p K a values and bond strengths (single, double, triple) leading to increased electrophilicity with lower p K a and increased nucleophile strength with higher p K a . More basic/nucleophilic functional groups desire to attack an electrophilic functional group with

5220-495: The growth of vegetation depending on the exact changes that occur. Crude oil and natural gas are the two largest sources of hydrocarbon contamination of soil. Bioremediation of hydrocarbon from soil or water contaminated is a formidable challenge because of the chemical inertness that characterize hydrocarbons (hence they survived millions of years in the source rock). Nonetheless, many strategies have been devised, bioremediation being prominent. The basic problem with bioremediation

5310-493: The halogens are not normally grouped separately. Others are sometimes put into major groups within organic chemistry and discussed under titles such as organosulfur chemistry , organometallic chemistry , organophosphorus chemistry and organosilicon chemistry . Organic reactions are chemical reactions involving organic compounds . Many of these reactions are associated with functional groups. The general theory of these reactions involves careful analysis of such properties as

5400-750: The idea of self-linking of carbon atoms (his paper appeared in June 1858), and provided the first molecular formulas where lines symbolize bonds connecting the atoms. For organic chemists, the theory of structure provided dramatic new clarity of understanding, and a reliable guide to both analytic and especially synthetic work. As a consequence, the field of organic chemistry developed explosively from this point. Among those who were most active in pursuing early structural investigations were, in addition to Kekulé and Couper, Frankland , Wurtz , Alexander Crum Brown , Emil Erlenmeyer , and Alexander Butlerov . Kekulé's idea of assigning certain atoms to certain positions within

5490-462: The lack of convention it was possible to have multiple names for the same compound. This led to the creation of the Geneva rules in 1892. The concept of functional groups is central in organic chemistry, both as a means to classify structures and for predicting properties. A functional group is a molecular module, and the reactivity of that functional group is assumed, within limits, to be the same in

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5580-476: The late summer of 1855. In 1895, Kekulé was ennobled by Kaiser Wilhelm II of Germany , giving him the right to add "von Stradonitz" to his name, referring to a possession of his patrilineal ancestors in Stradonice , Bohemia. His name thus became Friedrich August Kekule von Stradonitz, without the French accent on the last "e" of his name, and this is the form of the name that some libraries use. This title

5670-567: The molecule more acidic or basic due to their electronic influence on surrounding parts of the molecule. As the p K a (aka basicity ) of the molecular addition/functional group increases, there is a corresponding dipole , when measured, increases in strength. A dipole directed towards the functional group (higher p K a therefore basic nature of group) points towards it and decreases in strength with increasing distance. Dipole distance (measured in Angstroms ) and steric hindrance towards

5760-412: The molecule of interest. This parent name is then modified by prefixes, suffixes, and numbers to unambiguously convey the structure. Given that millions of organic compounds are known, rigorous use of systematic names can be cumbersome. Thus, IUPAC recommendations are more closely followed for simple compounds, but not complex molecules. To use the systematic naming, one must know the structures and names of

5850-548: The molecule, and schematically connecting them using what he called their "Verwandtschaftseinheiten" ("affinity units", now called " valences " or "bonds"), was based largely on evidence from chemical reactions, rather than on instrumental methods that could peer directly into the molecule, such as X-ray crystallography . Such physical methods of structural determination had not yet been developed, so chemists of Kekulé's day had to rely almost entirely on so-called "wet" chemistry. Some chemists, notably Hermann Kolbe , heavily criticized

5940-509: The multiple bonds to produce polyethylene , polybutylene , and polystyrene . The alkyne acetylene polymerizes to produce polyacetylene . Oligomers (chains of a few monomers) may be produced, for example in the Shell higher olefin process , where α-olefins are extended to make longer α-olefins by adding ethylene repeatedly. Some hydrocarbons undergo metathesis , in which substituents attached by C–C bonds are exchanged between molecules. For

6030-435: The organic dye now known as Perkin's mauve . His discovery, made widely known through its financial success, greatly increased interest in organic chemistry. A crucial breakthrough for organic chemistry was the concept of chemical structure, developed independently in 1858 by both Friedrich August Kekulé and Archibald Scott Couper . Both researchers suggested that tetravalent carbon atoms could link to each other to form

6120-464: The organic solute and with the organic solvent. Various specialized properties of molecular crystals and organic polymers with conjugated systems are of interest depending on applications, e.g. thermo-mechanical and electro-mechanical such as piezoelectricity , electrical conductivity (see conductive polymers and organic semiconductors ), and electro-optical (e.g. non-linear optics ) properties. For historical reasons, such properties are mainly

6210-422: The parent structures. Parent structures include unsubstituted hydrocarbons, heterocycles, and mono functionalized derivatives thereof. Nonsystematic nomenclature is simpler and unambiguous, at least to organic chemists. Nonsystematic names do not indicate the structure of the compound. They are common for complex molecules, which include most natural products. Thus, the informally named lysergic acid diethylamide

6300-769: The polarity of the molecules and their molecular weight. Some organic compounds, especially symmetrical ones, sublime . A well-known example of a sublimable organic compound is para-dichlorobenzene , the odiferous constituent of modern mothballs. Organic compounds are usually not very stable at temperatures above 300 °C, although some exceptions exist. Neutral organic compounds tend to be hydrophobic ; that is, they are less soluble in water than inorganic solvents. Exceptions include organic compounds that contain ionizable groups as well as low molecular weight alcohols , amines , and carboxylic acids where hydrogen bonding occurs. Otherwise, organic compounds tend to dissolve in organic solvents . Solubility varies widely with

6390-524: The polysaccharides), the nucleic acids (which include DNA and RNA as polymers), and the lipids . Besides, animal biochemistry contains many small molecule intermediates which assist in energy production through the Krebs cycle , and produces isoprene , the most common hydrocarbon in animals. Isoprenes in animals form the important steroid structural ( cholesterol ) and steroid hormone compounds; and in plants form terpenes , terpenoids , some alkaloids , and

6480-577: The proposed precursors, receive the same treatment, until available and ideally inexpensive starting materials are reached. Then, the retrosynthesis is written in the opposite direction to give the synthesis. A "synthetic tree" can be constructed because each compound and also each precursor has multiple syntheses. Hydrocarbon In organic chemistry , a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon . Hydrocarbons are examples of group 14 hydrides . Hydrocarbons are generally colourless and hydrophobic ; their odor

6570-401: The reactions of alkenes and oxygen. This process is the basis of rancidification and paint drying . Benzene burns with sooty flame when heated in air: Saturated hydrocarbons react with chlorine and fluorine . In the case of chlorination, one of the chlorine atoms replaces a hydrogen atom. The reactions proceed via free-radical pathways , in which the halogen first dissociates into

6660-449: The same 1890 speech, of an earlier vision of dancing atoms and molecules that led to his theory of structure, published in May 1858. This happened, he claimed, while he was riding on the upper deck of a horse-drawn omnibus in London. Once again, if one takes the anecdote as reflecting an accurate memory of a real event, circumstances related in the anecdote suggest that it must have occurred in

6750-737: The simple non-ring structured hydrocarbons have higher viscosities , lubricating indices, boiling points, and solidification temperatures. At the opposite extreme from methane lie the heavy tars that remain as the lowest fraction in a crude oil refining retort. They are collected and widely utilized as roofing compounds, pavement material ( bitumen ), wood preservatives (the creosote series) and as extremely high viscosity shear-resisting liquids. Some large-scale non-fuel applications of hydrocarbons begin with ethane and propane, which are obtained from petroleum and natural gas. These two gases are converted either to syngas or to ethylene and propylene respectively. Global consumption of benzene in 2021

6840-517: The source of virtually all synthetic organic compounds, including plastics and pharmaceuticals. Natural gas is consumed almost exclusively as fuel. Coal is used as a fuel and as a reducing agent in metallurgy . A small fraction of hydrocarbon found on earth, and all currently known hydrocarbon found on other planets and moons, is thought to be abiological . Hydrocarbons such as ethylene, isoprene, and monoterpenes are emitted by living vegetation. Some hydrocarbons also are widespread and abundant in

6930-429: The start of the 20th century, complexity of total syntheses has been increased to include molecules of high complexity such as lysergic acid and vitamin B 12 . The discovery of petroleum and the development of the petrochemical industry spurred the development of organic chemistry. Converting individual petroleum compounds into types of compounds by various chemical processes led to organic reactions enabling

7020-482: The study of aromatic compounds was in its earliest years, and too little evidence was then available to help chemists decide on any particular structure. More evidence was available by 1865, especially regarding the relationships of aromatic isomers . Kekulé argued for his proposed structure by considering the number of isomers observed for derivatives of benzene. For every monoderivative of benzene (C 6 H 5 X, where X = Cl, OH, CH 3 , NH 2 , etc.) only one isomer

7110-415: The subjects of the areas of polymer science and materials science . The names of organic compounds are either systematic, following logically from a set of rules, or nonsystematic, following various traditions. Systematic nomenclature is stipulated by specifications from IUPAC (International Union of Pure and Applied Chemistry). Systematic nomenclature starts with the name for a parent structure within

7200-513: The use of structural formulas that were offered, as he thought, without proof. However, most chemists followed Kekulé's lead in pursuing and developing what some have called "classical" structure theory, which was modified after the discovery of electrons (1897) and the development of quantum mechanics (in the 1920s). The idea that the number of valences of a given element was invariant was a key component of Kekulé's version of structural chemistry. This generalization suffered from many exceptions, and

7290-540: Was a German organic chemist . From the 1850s until his death, Kekulé was one of the most prominent chemists in Europe, especially in the field of theoretical chemistry . He was the principal founder of the theory of chemical structure and in particular the Kekulé structure of benzene . Kekulé never used his first given name; he was known throughout his life as August Kekulé. He did however say it once in his work. After he

7380-419: Was a re-parody of the monkey spoof, and was a mere invention rather than a recollection of an event in his life. Kekulé's 1890 speech, in which these anecdotes appeared, has been translated into English. If one takes the anecdote as reflecting an accurate memory of a real event, circumstances mentioned in the story suggest that it must have happened early in 1862. He told another autobiographical anecdote in

7470-507: Was cautious about claiming he had disproved vitalism, this was the first time a substance thought to be organic was synthesized in the laboratory without biological (organic) starting materials. The event is now generally accepted as indeed disproving the doctrine of vitalism. After Wöhler, Justus von Liebig worked on the organization of organic chemistry, being considered one of its principal founders. In 1856, William Henry Perkin , while trying to manufacture quinine , accidentally produced

7560-526: Was decisively influenced by Alexander Williamson . His Giessen doctoral degree was awarded in the summer of 1852. In 1856, Kekulé became Privatdozent at the University of Heidelberg . In 1858, he was hired as full professor at the University of Ghent , then in 1867 he was called to Bonn , where he remained for the rest of his career. Basing his ideas on those of predecessors such as Williamson, Charles Gerhardt , Edward Frankland , William Odling , Auguste Laurent , Charles-Adolphe Wurtz and others, Kekulé

7650-402: Was endowed with a "vital force". During the first half of the nineteenth century, some of the first systematic studies of organic compounds were reported. Around 1816 Michel Chevreul started a study of soaps made from various fats and alkalis . He separated the acids that, in combination with the alkali, produced the soap. Since these were all individual compounds, he demonstrated that it

7740-576: Was ennobled by the Kaiser in 1895, he adopted the name August Kekule von Stradonitz, without the French acute accent over the second "e". The French accent had apparently been added to the name by Kekulé's father during the Napoleonic occupation of Hesse by France, to ensure that French-speakers pronounced the third syllable. The son of a civil servant, Kekulé was born in Darmstadt , the capital of

7830-527: Was ever found, implying that all six carbons are equivalent, so that substitution on any carbon gives only a single possible product. For diderivatives such as the toluidines , C 6 H 4 (NH 2 )(CH 3 ), three isomers were observed, for which Kekulé proposed structures with the two substituted carbon atoms separated by one, two and three carbon-carbon bonds, later named ortho, meta, and para isomers respectively. The counting of possible isomers for diderivatives was, however, criticized by Albert Ladenburg ,

7920-471: Was possible to make a chemical change in various fats (which traditionally come from organic sources), producing new compounds, without "vital force". In 1828 Friedrich Wöhler produced the organic chemical urea (carbamide), a constituent of urine , from inorganic starting materials (the salts potassium cyanate and ammonium sulfate ), in what is now called the Wöhler synthesis . Although Wöhler himself

8010-449: Was subsequently replaced by the suggestion that valences were fixed at certain oxidation states . For example, periodic acid according to Kekuléan structure theory could be represented by the chain structure I-O-O-O-O-H. By contrast, the modern structure of (meta) periodic acid has all four oxygen atoms surrounding the iodine in a tetrahedral geometry. Kekulé's most famous work was on the structure of benzene . In 1865 Kekulé published

8100-436: Was the principal formulator of the theory of chemical structure (1857–58). This theory proceeds from the idea of atomic valence, especially the tetravalence of carbon (which Kekulé announced late in 1857) and the ability of carbon atoms to link to each other (announced in a paper published in May 1858), to the determination of the bonding order of all of the atoms in a molecule. Archibald Scott Couper independently arrived at

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