Cyanuric chloride is an organic compound with the formula 3. This white solid is the derivative of 1,3. It is the trimer of cyanogen chloride, cyanuric chloride is the main precursor to the popular but controversial herbicide atrazine. It is estimated that 70% of cyanuric chloride is used in the preparation of the triazine-class pesticides, cyanuric chloride is used as a precursor to dyes and crosslinking agents. The largest class of dyes are the sulfonated triazine-stilbene optical brighteners or fluorescent whitening agents commonly found in detergent formulas. Many reactive dyes incorporate a triazine ring and they are manufactured by way of the chloride displacement reaction shown above. Heating with DMF gives Golds reagent Me2NCH=NCH=NMe2+Cl−, which is a source of aminoalkylations. Cyanuric Chloride can be used as an alternative to oxalyl chloride in the Swern oxidation
1,3, 5-Trithiane is the chemical compound with the formula 3. This heterocycle is the trimer of the otherwise unstable species thioformaldehyde. It consists of a ring with alternating methylene bridges and thioether groups. It is prepared by treatment of formaldehyde with hydrogen sulfide, trithiane is a building block molecule in organic synthesis, being a masked source of formaldehyde. In one application, it is deprotonated with organolithium reagents to give the lithium derivative,3 + RLi →2 + RH2 + R’Br →2 + LiBr 2 + H2O → R’CHO + …. Trithiane is the dithioacetal of formaldehyde, other dithioacetals undergo similar reactions to the above. It is a precursor to other organosulfur reagents, the species often arise from thiation of ketones and aldehydes. The incipient thioketones and thioaldehydes suffer trimerization
A nitrile is any organic compound that has a −C≡N functional group. The prefix cyano- is used interchangeably with the nitrile in industrial literature. Nitriles are found in many compounds, including methyl cyanoacrylate, used in super glue, and nitrile rubber. Nitrile rubber is widely used as automotive and other seals since it is resistant to fuels and oils. Organic compounds containing multiple nitrile groups are known as cyanocarbons, inorganic compounds containing the −C≡N group are not called nitriles, but cyanides instead. Though both nitriles and cyanides can be derived from cyanide salts, most nitriles are not nearly as toxic, the N−C−C geometry is linear in nitriles, reflecting the sp hybridization of the triply bonded carbon. The C−N distance is short at 1.16 Å, consistent with a triple bond, Nitriles are polar, as indicated by high dipole moments. As liquids, they have high dielectric constants, often in the 30s, the first compound of the homolog row of nitriles, the nitrile of formic acid, hydrogen cyanide was first synthesized by C. W.
Scheele in 1782. In 1811 J. L. Gay-Lussac was able to prepare the very toxic, théophile-Jules Pelouze synthesized propionitrile in 1834 suggesting it to be an ether of propionic alcohol and hydrocyanic acid. The synthesis of benzonitrile by Hermann Fehling in 1844, by heating ammonium benzoate, was the first method yielding enough of the substance for chemical research and he determined the structure by comparing it to the already known synthesis of hydrogen cyanide by heating ammonium formate to his results. He coined the name nitrile for the substance, which became the name for this group of compounds. Industrially, the methods for producing nitriles are ammoxidation and hydrocyanation. Both routes are green in the sense that they do not generate stoichiometric amounts of salts, in ammoxidation, a hydrocarbon is partially oxidized in the presence of ammonia. This conversion is practiced on a scale for acrylonitrile, CH3CH=CH2 + 3⁄2 O2 + NH3 → NCCH=CH2 +3 H2O In the production of acrylonitrile.
On an industrial scale, several derivatives of benzonitrile, the process is catalysed by metal oxides and is assumed to proceed via the imine. Hydrocyanation is a method for producing nitriles from hydrogen cyanide. In the Kolbe nitrile synthesis, alkyl halides undergo nucleophilic aliphatic substitution with alkali metal cyanides, aryl nitriles are prepared in the Rosenmund-von Braun synthesis. The cyanohydrins are a class of nitriles
1,3, 5-Trioxane, sometimes called trioxane or trioxin, is a chemical compound with molecular formula C3H6O3. It is a solid with a chloroform-like odor. Thus, cyclotrimerization of formaldehyde affords 1,3, 5-trioxane, Trioxane is produced by trimerization of formaldehyde using acid catalysts, the reaction is conducted in concentrated aqueous solution and the product is separated by solvent extraction. An idealized mechanism is shown below, Trioxane is mainly consumed in the production of polyoxymethylene plastics, other applications exploit its tendency to release formaldehyde. As such it is used as a binder in textiles, wood products, Trioxane is combined with hexamine and compressed into solid bars to make hexamine fuel tablets, used by the military and outdoorsmen as a cooking fuel. In the laboratory, trioxane is used as a source of formaldehyde
Cyclododecatrienes are cyclic trienes with the formula C12H18. Four isomers are known for 1,5, 9-cyclododecatriene, the trans, cis-isomer is a precursor in the production of nylon-12. The trans, cis-isomer is obtained by cyclotrimerization of butadiene catalyzed by a mixture of titanium tetrachloride, production capacity in 1995 was 8000 tons. As aforementioned, titanium catalysts predominately produce the important cis, the all-trans isomer is, the product from nickel- and chromium-catalyzed trimerization reactions. The yield of cyclododecatriene through these methods is often greater than 80%, the principal side products are the dimers and oligomers of butadiene. All of the isomers of 1,5, 9-cyclododecatriene are colorless, possess typical terpene-like odors, the all-trans isomer melts at 34 °C while the other three isomers melt below room temperature. All of the isomers behave like typical olefins, the all-trans and cis, trans isomers in particular tend to form complexes with transition metals.
They undergo transannular reactions and isomerization, in the final step this mixture oxidized further by nitric acid, The alcohol and the ketone can be purified from the alcohol/ketone mixture under different reaction conditions. Pure cyclododecanol can be produced from the hydrogenation of the mixture in the presence of a copper-chromium catalyst at 30 MPa and 160 ˚C, pure cyclododecanone can be converted into cyclododecanone oxime, which yields laurolactam after Beckmann rearrangement. Laurolactam is the precursor to plastics, such as polyamide 12. In March 2012, a fire at the Evonik Industries plant in Marl, the plant produced a substantial proportion of the worlds production of CDT, particularly that needed to produce laurolactam, a precursor to the polyamide PA12. This in turn led to concerns for global production of finished goods, other biobased polyamides, not dependent on laurolactam or CDT, have been put forward as alternative materials
1,3, 5-triazine, called s-triazine, is an organic chemical compound with the formula 3. It is a heterocyclic aromatic ring, one of several isomeric triazines. S-triazine and its derivatives are useful in a variety of applications, symmetrical 1,3, 5-triazines are prepared by trimerization of certain nitriles such as cyanogen chloride or cyanimide. Benzoguanamine is synthesised from benzonitrile and dicyandiamide, as a reagent in organic synthesis, s-triazine is used as the equivalent of hydrogen cyanide. Being a solid, triazine is sometimes easier to handle in the laboratory, one application is in the Gattermann reaction, used to attach the formyl group to aromatic substrates. N- and C-substituted triazines are used industrially, the most common derivative of 1,3, 5-triazine is 1,3, 5-triazine-2,4, 6-triamine, commonly known as melamine or cyanuramide. Another important derivative is 1,3, 5-triazine-2,4,2,4, 6-Trichloro-1,3, 5-triazine is the starting point for the manufacture of many herbicides such as Simazine and atrazine.
Chlorinated triazines are the basis of an important family of reactive dyes, triazines are found in pharmaceutical products
Pyrolysis is a thermochemical decomposition of organic material at elevated temperatures in the absence of oxygen. It involves the change of chemical composition and physical phase. The word is coined from the Greek-derived elements pyro fire and lysis separating, Pyrolysis is a type of thermolysis, and is most commonly observed in organic materials exposed to high temperatures. It is one of the involved in charring wood, starting at 200–300 °C. It occurs in fires where solid fuels are burning or when vegetation comes into contact with lava in volcanic eruptions, in general, pyrolysis of organic substances produces gas and liquid products and leaves a solid residue richer in carbon content, char. Extreme pyrolysis, which leaves mostly carbon as the residue, is called carbonization and these specialized uses of pyrolysis may be called various names, such as dry distillation, destructive distillation, or cracking. Pyrolysis is used in the creation of nanoparticles, Pyrolysis plays an important role in several cooking procedures, such as baking, frying and caramelizing.
It is a tool of analysis, for example, in mass spectrometry. Indeed, many important chemical substances, such as phosphorus and sulfuric acid, were first obtained by this process, Pyrolysis has been assumed to take place during catagenesis, the conversion of buried organic matter to fossil fuels. It is the basis of pyrography, in their embalming process, the ancient Egyptians used a mixture of substances, including methanol, which they obtained from the pyrolysis of wood. Pyrolysis differs from other processes like combustion and hydrolysis in that it usually does not involve reactions with oxygen, water, in practice, it is not possible to achieve a completely oxygen-free atmosphere. Because some oxygen is present in any system, a small amount of oxidation occurs. The term has applied to the decomposition of organic material in the presence of superheated water or steam, for example. Pyrolysis is usually the first chemical reaction occurs in the burning of many solid organic fuels, like wood and paper.
Thus, the pyrolysis of common materials like wood, plastic, in pyrolysis there is a gas phase present. Pyrolysis occurs whenever food is exposed to high temperatures in a dry environment, such as roasting, toasting. It is the process responsible for the formation of the golden-brown crust in foods prepared by those methods. In normal cooking, the food components that undergo pyrolysis are carbohydrates
Benzene is an important organic chemical compound with the chemical formula C6H6. The benzene molecule is composed of 6 carbon atoms joined in a ring with 1 hydrogen atom attached to each, because it contains only carbon and hydrogen atoms, benzene is classed as a hydrocarbon. Benzene is a constituent of crude oil and is one of the elementary petrochemicals. Because of the cyclic continuous pi bond between the atoms, benzene is classed as an aromatic hydrocarbon, the second -annulene. Benzene is a colorless and highly flammable liquid with a sweet smell and it is used primarily as a precursor to the manufacture of chemicals with more complex structure, such as ethylbenzene and cumene, of which billions of kilograms are produced. Because benzene has a high number, it is an important component of gasoline. Because benzene is a carcinogen, most non-industrial applications have been limited. The word benzene derives historically from gum benzoin, a resin known to European pharmacists. An acidic material was derived from benzoin by sublimation, and named flowers of benzoin, the hydrocarbon derived from benzoic acid thus acquired the name benzin, benzol, or benzene.
Michael Faraday first isolated and identified benzene in 1825 from the oily residue derived from the production of illuminating gas, in 1833, Eilhard Mitscherlich produced it by distilling benzoic acid and lime. He gave the compound the name benzin, in 1845, Charles Mansfield, working under August Wilhelm von Hofmann, isolated benzene from coal tar. Four years later, Mansfield began the first industrial-scale production of benzene, the sense developed among chemists that a number of substances were chemically related to benzene, comprising a diverse chemical family. In 1855, Hofmann used the word aromatic to designate this family relationship, in 1997, benzene was detected in deep space. The empirical formula for benzene was known, but its highly polyunsaturated structure. In 1865, the German chemist Friedrich August Kekulé published a paper in French suggesting that the structure contained a ring of six carbon atoms with alternating single and double bonds, the next year he published a much longer paper in German on the same subject.
Kekulés symmetrical ring could explain these facts, as well as benzenes 1,1 carbon-hydrogen ratio. Here Kekulé spoke of the creation of the theory and 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 vision, he said, came to him years of studying the nature of carbon-carbon bonds
Urea, known as carbamide, is an organic compound with the chemical formula CO2. This amide has two groups joined by a carbonyl functional group. Urea serves an important role in the metabolism of nitrogen-containing compounds by animals and is the main nitrogen-containing substance in the urine of mammals and it is a colorless, odorless solid, highly soluble in water, and practically non-toxic. Dissolved in water, it is neither acidic nor alkaline, the body uses it in many processes, most notably nitrogen excretion. The liver forms it by combining two molecules with a carbon dioxide molecule in the urea cycle. Urea is widely used in fertilizers as a source of nitrogen and is an important raw material for the chemical industry, Friedrich Wöhlers discovery in 1828 that urea can be produced from inorganic starting materials was an important conceptual milestone in chemistry. More than 90% of world production of urea is destined for use as a nitrogen-release fertilizer. Urea has the highest nitrogen content of all solid nitrogenous fertilizers in common use, therefore, it has the lowest transportation costs per unit of nitrogen nutrient.
The standard crop-nutrient rating of urea is 46-0-0, many soil bacteria possess the enzyme urease, which catalyzes conversion of urea to ammonia or ammonium ion and bicarbonate ion. Thus urea fertilizers rapidly transform to the form in soils. Ammonium and nitrate are readily absorbed by plants, and are the dominant sources of nitrogen for plant growth, Urea is used in many multi-component solid fertilizer formulations. Urea is highly soluble in water and is very suitable for use in fertilizer solutions. For fertilizer use, granules are preferred over prills because of their particle size distribution. The most common impurity of synthetic urea is biuret, which impairs plant growth, Urea is usually spread at rates of between 40 and 300 kg/ha but rates vary. Smaller applications incur lower losses due to leaching, during summer, urea is often spread just before or during rain to minimize losses from volatilization. Because of the nitrogen concentration in urea, it is very important to achieve an even spread.
The application equipment must be calibrated and properly used. Drilling must not occur on contact with or close to seed, Urea dissolves in water for application as a spray or through irrigation systems
An alkyne trimerisation reaction is a 2+2+2 cyclization reaction in which three alkyne molecules react to form an aromatic compound. Berthelot reported the first example of leading to aromatic products in 1866. The reaction required very high temperatures to proceed and produced a mixture of products. The reaction is highly chemoselective for triple bonds and can tolerate a variety of functional groups on the starting materials. For cotrimerizations involving two or three different acetylenes, a variety of regioisomers may form, these reactions usually require elevated temperatures and sometimes require irradiation to facilitate the dissociation of strongly binding carbon monoxide ligands. Catalyst deactivation can occur through the formation of stable, 18-electron η4-complexes incorporating cyclobutadiene, the most problematic side products of the reaction are due to cyclotetramerization and alkyne dimerization. The most common mechanism for the cyclotrimerization of acetylenes begins with the formation of a metallocyclopentadiene complex, oxidative cyclization of two coordinated alkyne units produces either metallocycle 3 or 4.
After dissociation of a ligand and coordination of a third alkyne. Either alkyne insertion generates metallocycloheptatriene 5, or cycloaddition generates bridged bicycle 6, the former pathway is questionable however, as reductive elimination from a metallocycloheptatriene to form an arene is symmetry forbidden. A third pathway proposed for ruthenium catalysts involves formal cycloaddition of the alkyne followed by rearrangement, reductive elimination, the intermediacy of bicycle 7 was supported by DFT calculations. For cyclotrimerization reactions of asymmetrically substituted acetylenes, a number of products are possible. The substitution pattern about the product depends on two events, formation of the metallocyclopentadiene intermediate and incorporation of the third equivalent of alkyne. Although both head-to-head and tail-to-tail metallocyclopentadienes lead to 1, a number of acetylenic substrates selectively form regioisomers of type 2, steric bulk on the alkyne coupling partners and catalyst have been invoked as the controlling elements of regioselectivity.
Chiral catalysts have been employed in combination with arynes to produce amounts of atropisomeric products. Selective cyclotrimerization of one of a pair of enantiotopic alkynes has facilitated by a chiral catalyst. Hoewever, the reaction is not generally compatible with unsaturated functionalities other than carbonyl compounds, for instance, in addition, some reactions are limited by catalyst deactivation via formation of stable, 18-electron η4-complexes. Cyclobutadiene and arene complexes have all been observed as off-cycle, in addition to high-order polymers and dimers and trimers, which originate from low regio- and chemoselectivities, enyne side products derived from alkyne dimerization have been observed. Rhodium catalysts are particularly adept at enyne formation, for nickel catalysis, formation of larger rings can be a problem
Acetylene is the chemical compound with the formula C2H2. It is a hydrocarbon and the simplest alkyne and this colorless gas is widely used as a fuel and a chemical building block. It is unstable in its form and thus is usually handled as a solution. Pure acetylene is odorless, but commercial grades usually have a marked odor due to impurities, as an alkyne, acetylene is unsaturated because its two carbon atoms are bonded together in a triple bond. The carbon–carbon triple bond places all four atoms in the straight line. Acetylene was discovered in 1836 by Edmund Davy, who identified it as a new carburet of hydrogen and it was rediscovered in 1860 by French chemist Marcellin Berthelot, who coined the name acétylène. Berthelots empirical formula for acetylene, as well as the alternative name quadricarbure dhydrogène were incorrect because chemists at that used the wrong atomic mass for carbon. Berthelot was able to prepare this gas by passing vapours of organic compounds through a red-hot tube and he found acetylene was formed by sparking electricity through mixed cyanogen and hydrogen gases.
Berthelot obtained acetylene directly by passing hydrogen between the poles of a carbon arc, commercially available acetylene gas could smell foul due to the common impurities hydrogen sulfide and phosphine. However, as purity increases it will become odourless, since the 1950s, acetylene has mainly been manufactured by the partial combustion of methane or appears as a side product in the ethylene stream from cracking of hydrocarbons. Approximately 400,000 tonnes were produced by method in 1983. Its presence in ethylene is usually undesirable because of its explosive character and it is selectively hydrogenated into ethylene, usually using Pd–Ag catalysts. Until the 1950s, when oil supplanted coal as the source of reduced carbon. In the US, this process was an important part of the late-19th century revolution in chemistry enabled by the hydroelectric power project at Niagara Falls. In terms of valence bond theory, in each carbon atom the 2s orbital hybridizes with one 2p orbital thus forming an sp hybrid, the other two 2p orbitals remain unhybridized.
The two ends of the two sp hybrid orbital overlap to form a strong σ valence bond between the carbons, while on each of the two ends hydrogen atoms attach by σ bonds. The two unchanged 2p orbitals form a pair of weaker π bonds, since acetylene is a linear symmetrical molecule, it possesses the D∞h point group. At atmospheric pressure, acetylene cannot exist as a liquid and does not have a melting point, the triple point on the phase diagram corresponds to the melting point at the minimum pressure at which liquid acetylene can exist