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Crotonaldehyde
Crotonaldehyde is a chemical compound with the formula CH3CH=CHCHO. The compound is usually sold as a mixture of the ''E''- and ''Z''-isomers, which differ with respect to the relative position of the methyl and formyl groups. The ''E''-isomer is more common (data given in Table is for the ''E''-isomer). This lachrymatory liquid is moderately soluble in water and miscible in organic solvents. As an unsaturated aldehyde, crotonaldehyde is a versatile intermediate in organic synthesis. It occurs in a variety of foodstuffs, e.g. soybean oils. Production and reactivity Crotonaldehyde is produced by the aldol condensation of acetaldehyde: :2 CH3CHO → CH3CH=CHCHO + H2O Crotonaldehyde is a multifunctional molecule that exhibits diverse reactivity. It is a prochiral dienophile. It is a Michael acceptor. Addition of methylmagnesium chloride produces 3-penten-2-ol. Polyurethane catalyst ''N'',''N'',''N''′,''N''′-tetramethyl-1,4-butanediamine (also known as NIAX TMBD ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crotyl Alcohol
Crotyl alcohol, or crotonyl alcohol, is an unsaturated alcohol. It is a colourless liquid that is moderately soluble in water and miscible with most organic solvents. Two isomers of this alcohol exist, cis and trans. It can be synthesized by the hydrogenation of crotonaldehyde. The compound is of little commercial interest.. See also * Crotyl * Allyl alcohol * Crotonaldehyde Crotonaldehyde is a chemical compound with the formula CH3CH=CHCHO. The compound is usually sold as a mixture of the ''E''- and ''Z''-isomers, which differ with respect to the relative position of the methyl and formyl groups. The ''E''-isomer ... * Crotonic acid References Primary alcohols Alkene derivatives Crotyl compounds {{alcohol-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crotonic Acid
Crotonic acid ((2''E'')-but-2-enoic acid) is a short-chain unsaturated carboxylic acid, described by the formula CH3CH=CHCO2H. It is called crotonic acid because it was erroneously thought to be a saponification product of croton oil. It crystallizes as colorless needles from hot water. The ''cis''-isomer of crotonic acid is called isocrotonic acid. Crotonic acid is soluble in water and many organic solvents. Its odor is similar to butyric acid. Production Crotonic acid may be obtained by several methods: *by oxidation of crotonaldehyde: : *by Knoevenagel condensation of acetaldehyde with malonic acid in pyridine: : *or by alkaline hydrolysis of allyl cyanide after the intramolecular rearrangement of the double bond: : *Furthermore, it is formed during the distillation of 3-hydroxybutyric acid: : Properties Crotonic acid crystallizes in the monoclinic crystal system in the space group P21/a (space group 14, position 3) with the lattice parameters , , and . The uni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acrolein
Acrolein (systematic name: propenal) is the simplest unsaturated aldehyde. It is a colorless liquid with a piercing, acrid smell. The smell of burnt fat (as when cooking oil is heated to its smoke point) is caused by glycerol in the burning fat breaking down into acrolein. It is produced industrially from propylene and mainly used as a biocide and a building block to other chemical compounds, such as the amino acid methionine. History Acrolein was first named and characterized as an aldehyde by the Swedish chemist Jöns Jacob Berzelius in 1839. He had been working with it as a thermal degradation product of glycerol, a material used in the manufacture of soap. The name is a contraction of ‘acrid’ (referring to its pungent smell) and ‘oleum’ (referring to its oil-like consistency). In the 20th century, acrolein became an important intermediate for the industrial production of acrylic acid and acrylic plastics. Production Acrolein is prepared industrially by oxidation o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cis-3-hexenal
''cis''-3-Hexenal, also known as (''Z'')-3-hexenal and leaf aldehyde, is an organic compound with the formula CH3CH2CH=CHCH2CHO. It is classified as an unsaturated aldehyde. It is a colorless liquid and an aroma compound with an intense odor of freshly cut grass and leaves. Occurrence It is one of the major volatile compounds in ripe tomatoes, although it tends to isomerize into the conjugated ''trans''-2-hexenal. It is produced in small amounts by most plants and it acts as an attractant to many predatory insects. It is also a pheromone in many insect species. See also * ''cis''-3-hexen-1-ol has a similar but weaker odor and is used in flavors and perfumes. *1-Hexanol, another volatile organic compound Volatile organic compounds (VOCs) are organic compounds that have a high vapour pressure at room temperature. High vapor pressure correlates with a low boiling point, which relates to the number of the sample's molecules in the surrounding air, a ..., also considered ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Merck Index
''The Merck Index'' is an encyclopedia of chemicals, drugs and biologicals with over 10,000 monograph on single substances or groups of related compounds published online by the Royal Society of Chemistry. History The first edition of the Merck's Index was published in 1889 by the German chemical company Emanuel Merck and was primarily used as a sales catalog for Merck's growing list of chemicals it sold. The American subsidiary was established two years later and continued to publish it. During World War I the US government seized Merck's US operations and made it a separate American "Merck" company that continued to publish the Merck Index. In 2012 the Merck Index was licensed to the Royal Society of Chemistry. An online version of The Merck Index, including historic records and new updates not in the print edition, is commonly available through research libraries. It also includes an appendix with monographs on organic named reactions. The 15th edition was published in A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prochiral
In stereochemistry, prochiral molecules are those that can be converted from achiral to chiral in a single step. An achiral species which can be converted to a chiral in two steps is called proprochiral. If two identical substituents are attached to a sp3-hybridized atom, the descriptors ''pro''-R and ''pro''-S are used to distinguish between the two. Promoting the ''pro''-R substituent to higher priority than the other identical substituent results in an ''R'' chirality center at the original sp3-hybridized atom, and analogously for the ''pro''-S substituent. A trigonal planar sp2-hybridized atom can be converted to a chiral center when a substituent is added to the ''re'' or ''si'' () face of the molecule. A face is labeled ''re'' if, when looking at that face, the substituents at the trigonal atom are arranged in increasing Cahn-Ingold-Prelog priority order (1 to 2 to 3) in a clockwise order, and ''si'' if the priorities increase in anti-clockwise order; note that the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methacrolein
Methacrolein, or methacrylaldehyde, is an unsaturated aldehyde. It is a clear, colorless, flammable liquid. Methacrolein is one of two major products resulting from the reaction of isoprene with OH in the atmosphere, the other product being methyl vinyl ketone (MVK, also known as butenone). These compounds are important components of the atmospheric oxidation chemistry of biogenic chemicals, which can result in the formation of ozone and/or particulates. Methacrylaldehyde is also present in cigarette smoke. It can be found in the essential oil of the plant Big Sagebrush (''Artemisia tridentata'') which contains 5% methacrolein. Industrially, the primary use of methacrolein is in the manufacture of polymers and synthetic resins. Exposure to methacrolein is highly irritating to the eyes, nose, throat and lungs. See also * Acrolein * Methacrylic acid Methacrylic acid, abbreviated MAA, is an organic compound. This colorless, viscous liquid is a carboxylic acid with an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crotyl
{{Unreferenced, date=November 2021 A crotyl group is an organic functional group with the formula RCH2CH=CHCH3. Systematically, it is called a but-2-en-1-yl group and exhibits geometric isomerism, being either ''cis'' (''Z'') or ''trans'' (''E''). There are many simple compounds in which the crotyl group forms base carbon chain: crotyl alcohol, crotonaldehyde, crotonic acid, and crotyl acrylate are examples. Synthesis of crotylates Crotylate (crotyl anions) can be synthesised from 2-butene (either isomer): this reaction must be performed in the presence of organometallic reagents, as a base, usually alkyl lithium, or any alkylates of ''s''-block metals, in a solvent, typically THF, and at low temperatures, generally below -20 °C. The negative charge is delocalised over three of the carbon atoms of the crotylate group and there is resonance between the two possible delocalised forms (one for each terminal carbon). Crotylation reactions Crotylation readily occurs with alkoxy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Controlled-release Fertilizer
224px, Methylene diurea (MDU) is component of the most popular controlled-release fertilizers. A controlled-release fertiliser (CRF) is a granulated fertiliser that releases nutrients gradually into the soil (i.e., with a controlled release period). Controlled-release fertilizer is also known as controlled-availability fertilizer, delayed-release fertilizer, metered-release fertilizer, or slow-acting fertilizer. Usually CRF refers to nitrogen-based fertilizers. Slow- and controlled-release involve only 0.15% (562,000 tons) of the fertilizer market (1995). History Controlled-nitrogen-release technologies based on polymers derived from combining urea and formaldehyde were first produced in 1936 and commercialized in 1955. The early product had 60 percent of the total nitrogen cold-water-insoluble, and the unreacted (quick-release) less than 15%. Methylene ureas, e.g. methylene diurea, were commercialized in the 1960s and 1970s, having 25% and 60% of the nitrogen as cold-water-insolu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyrimidine
Pyrimidine (; ) is an aromatic, heterocyclic, organic compound similar to pyridine (). One of the three diazines (six-membered heterocyclics with two nitrogen atoms in the ring), it has nitrogen atoms at positions 1 and 3 in the ring. The other diazines are pyrazine (nitrogen atoms at the 1 and 4 positions) and pyridazine (nitrogen atoms at the 1 and 2 positions). In nucleic acids, three types of nucleobases are pyrimidine derivatives: cytosine (C), thymine (T), and uracil (U). Occurrence and history The pyrimidine ring system has wide occurrence in nature as substituted and ring fused compounds and derivatives, including the nucleotides cytosine, thymine and uracil, thiamine (vitamin B1) and alloxan. It is also found in many synthetic compounds such as barbiturates and the HIV drug, zidovudine. Although pyrimidine derivatives such as alloxan were known in the early 19th century, a laboratory synthesis of a pyrimidine was not carried out until 1879, when Grimaux reporte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vitamin E
Vitamin E is a group of eight fat soluble compounds that include four tocopherols and four tocotrienols. Vitamin E deficiency, which is rare and usually due to an underlying problem with digesting dietary fat rather than from a diet low in vitamin E, can cause nerve problems. Vitamin E is a fat-soluble antioxidant which may help protect cell membranes from reactive oxygen species. Worldwide, government organizations recommend adults consume in the range of 3 to 15 mg per day. As of 2016, consumption was below recommendations according to a worldwide summary of more than one hundred studies that reported a median dietary intake of 6.2 mg per day for alpha-tocopherol. Population studies suggested that people who consumed foods with more vitamin E, or who chose on their own to consume a vitamin E dietary supplement, had lower incidence of cardiovascular diseases, cancer, dementia, and other diseases. However, placebo-controlled clinical trials using alpha-tocopherol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sorbic Acid
Sorbic acid, or 2,4-hexadienoic acid, is a natural organic compound used as a food preservative. It has the chemical formula and the structure . It is a colourless solid that is slightly soluble in water and sublimes readily. It was first isolated from the unripe berries of the ''Sorbus aucuparia'' (rowan tree), hence its name. Production The traditional route to sorbic acid involves condensation of malonic acid and crotonaldehyde. It can also be prepared from isomeric hexadienoic acids, which are available via a nickel-catalyzed reaction of allyl chloride, acetylene, and carbon monoxide. The route used commercially, however, is from crotonaldehyde and ketene. An estimated 30,000 tons are produced annually. History Sorbic acid was isolated in 1859 by distillation of rowanberry oil by A. W. von Hofmann. This affords parasorbic acid, the lactone of sorbic acid, which he converted to sorbic acid by hydrolysis. Its antimicrobial activities were discovered in the late 1930s an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
