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Propynyllithium
Propynyllithium is an organolithium compound with the chemical formula . It is a white solid that is soluble in 1,2-dimethoxyethane, and tetrahydrofuran. To preclude its degradation by oxygen and water, propynyllithium and its solutions are handled under inert gas (argon or nitrogen). Although commonly depicted as a monomer, propynyllithium adopts a more complicated cluster structure as seen for many other organolithium compounds. Synthesis Various preparations of propynyllithium are known, but the most expeditious route starts with 1-bromopropene: :CH3CH=CHBr + 2 BuLi → CH3C≡CLi + 2 BuH + LiBr Historic routes It can be prepared by passing propyne gas through a solution of ''n''-butyllithium or by direct metallization of propyne with lithium in liquid ammonia or other solvent. Propyne, however, is an expensive gas, and, therefore, it is sometimes replaced by less expensive gas mixtures used for welding and containing a small percentage of propyne. Applicatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Propyne
Propyne (methylacetylene) is an alkyne with the chemical formula . It is a component of MAPD gas—along with its isomer propadiene (allene), which was commonly used in gas welding. Unlike acetylene, propyne can be safely condensed.Peter Pässler, Werner Hefner, Klaus Buckl, Helmut Meinass, Andreas Meiswinkel, Hans-Jürgen Wernicke, Günter Ebersberg, Richard Müller, Jürgen Bässler, Hartmut Behringer, Dieter Mayer, "Acetylene" in Ullmann's Encyclopedia of Industrial Chemistry Wiley-VCH, Weinheim 2007 (). Production and equilibrium with propadiene Propyne exists in equilibrium with propadiene, the mixture of propyne and propadiene being called MAPD: : The coefficient of equilibrium ''K''eq is 0.22 at 270 °C or 0.1 at 5 °C. MAPD is produced as a side product, often an undesirable one, by cracking propane to produce propene, an important feedstock in the chemical industry. MAPD interferes with the catalytic polymerization of propene. Laboratory methods Propyn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organolithium Compound
In organometallic chemistry, organolithium reagents are chemical compounds that contain carbon–lithium (C–Li) bonds. These reagents are important in organic synthesis, and are frequently used to transfer the organic group or the lithium atom to the substrates in synthetic steps, through nucleophilic addition or simple deprotonation. Organolithium reagents are used in industry as an initiator for anionic polymerization, which leads to the production of various elastomers. They have also been applied in asymmetric synthesis in the pharmaceutical industry. Due to the large difference in electronegativity between the carbon atom and the lithium atom, the C−Li bond is highly ionic. Owing to the polar nature of the C−Li bond, organolithium reagents are good nucleophiles and strong bases. For laboratory organic synthesis, many organolithium reagents are commercially available in solution form. These reagents are highly reactive, and are sometimes pyrophoric. History and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1,2-dimethoxyethane
Dimethoxyethane, also known as glyme, monoglyme, dimethyl glycol, ethylene glycol dimethyl ether, dimethyl cellosolve, and DME, is a colorless, aprotic, and liquid ether that is used as a solvent, especially in batteries. Dimethoxyethane is miscible with water. Production Monoglyme is produced industrially by the reaction of dimethylether with ethylene oxide: :CH3OCH3 + CH2CH2O → CH3OCH2CH2OCH3 Applications as solvent and ligand left, 144px, Structure of the coordination complex NbCl3(dimethoxyethane)(3-hexyne). Together with a high-permittivity solvent (e.g. propylene carbonate), dimethoxyethane is used as the low-viscosity component of the solvent for electrolytes of lithium batteries. In the laboratory, DME is used as a coordinating solvent. Dimethoxyethane is often used as a higher-boiling-point alternative to diethyl ether and tetrahydrofuran. Dimethoxyethane acts as a bidentate ligand for some metal cations. It is therefore often used in organometallic chemistry. Gri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetrahydrofuran
Tetrahydrofuran (THF), or oxolane, is an organic compound with the formula (CH2)4O. The compound is classified as heterocyclic compound, specifically a cyclic ether. It is a colorless, water- miscible organic liquid with low viscosity. It is mainly used as a precursor to polymers. Being polar and having a wide liquid range, THF is a versatile solvent. It is an isomer of another solvent, butanone. Production About 200,000 tonnes of tetrahydrofuran are produced annually. The most widely used industrial process involves the acid-catalyzed dehydration of 1,4-Butanediol, 1,4-butanediol. Ashland Inc., Ashland/ISP is one of the biggest producers of this chemical route. The method is similar to the production of diethyl ether from ethanol. The butanediol is derived from Condensation reaction, condensation of acetylene with formaldehyde followed by hydrogenation. DuPont developed a process for producing THF by oxidizing Butane#Isomers, ''n''-butane to crude maleic anhydride, follow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Argon
Argon is a chemical element; it has symbol Ar and atomic number 18. It is in group 18 of the periodic table and is a noble gas. Argon is the third most abundant gas in Earth's atmosphere, at 0.934% (9340 ppmv). It is more than twice as abundant as water vapor (which averages about 4000 ppmv, but varies greatly), 23 times as abundant as carbon dioxide (400 ppmv), and more than 500 times as abundant as neon (18 ppmv). Argon is the most abundant noble gas in Earth's crust, comprising 0.00015% of the crust. Nearly all argon in Earth's atmosphere is radiogenic argon-40, derived from the decay of potassium-40 in Earth's crust. In the universe, argon-36 is by far the most common argon isotope, as it is the most easily produced by stellar nucleosynthesis in supernovas. The name "argon" is derived from the Greek word , neuter singular form of meaning 'lazy' or 'inactive', as a reference to the fact that the element undergoes almost no chemical reactions. The complete oc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrogen
Nitrogen is a chemical element; it has Symbol (chemistry), symbol N and atomic number 7. Nitrogen is a Nonmetal (chemistry), nonmetal and the lightest member of pnictogen, group 15 of the periodic table, often called the Pnictogen, pnictogens. It is a common element in the universe, estimated at Abundance of the chemical elements, seventh in total abundance in the Milky Way and the Solar System. At standard temperature and pressure, two atoms of the element chemical bond, bond to form N2, a colourless and odourless diatomic molecule, diatomic gas. N2 forms about 78% of Atmosphere of Earth, Earth's atmosphere, making it the most abundant chemical species in air. Because of the volatility of nitrogen compounds, nitrogen is relatively rare in the solid parts of the Earth. It was first discovered and isolated by Scottish physician Daniel Rutherford in 1772 and independently by Carl Wilhelm Scheele and Henry Cavendish at about the same time. The name was suggested by French chemist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammonia
Ammonia is an inorganic chemical compound of nitrogen and hydrogen with the chemical formula, formula . A Binary compounds of hydrogen, stable binary hydride and the simplest pnictogen hydride, ammonia is a colourless gas with a distinctive pungent smell. It is widely used in fertilizers, refrigerants, explosives, cleaning agents, and is a precursor for numeous chemicals. Biologically, it is a common nitrogenous waste, and it contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to fertilisers. Around 70% of ammonia produced industrially is used to make fertilisers in various forms and composition, such as urea and diammonium phosphate. Ammonia in pure form is also applied directly into the soil. Ammonia, either directly or indirectly, is also a building block for the synthesis of many chemicals. In many countries, it is classified as an List of extremely hazardous substances, extremely hazardous substance. Ammonia is toxic, cau ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organic Synthesis
Organic synthesis is a branch of chemical synthesis concerned with the construction of organic compounds. Organic compounds are molecules consisting of combinations of covalently-linked hydrogen, carbon, oxygen, and nitrogen atoms. Within the general subject of organic synthesis, there are many different types of synthetic routes that can be completed including total synthesis, Enantioselective synthesis, stereoselective synthesis, automated synthesis, and many more. Additionally, in understanding organic synthesis it is necessary to be familiar with the methodology, techniques, and applications of the subject. Total synthesis A total synthesis refers to the complete chemical synthesis of molecules from simple, Precursor (chemistry), natural precursors. Total synthesis is accomplished either via a linear or convergent approach. In a Linear synthesis, ''linear'' synthesis—often adequate for simple structures—several steps are performed sequentially until the molecule is com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nucleophile
In chemistry, a nucleophile is a chemical species that forms bonds by donating an electron pair. All molecules and ions with a free pair of electrons or at least one pi bond can act as nucleophiles. Because nucleophiles donate electrons, they are Lewis bases. ''Nucleophilic'' describes the affinity of a nucleophile to bond with positively charged Atomic nucleus, atomic nuclei. Nucleophilicity, sometimes referred to as nucleophile strength, refers to a substance's nucleophilic character and is often used to compare the affinity of atoms. Neutral nucleophilic reactions with solvents such as Alcohol (chemistry), alcohols and water are named solvolysis. Nucleophiles may take part in nucleophilic substitution, whereby a nucleophile becomes attracted to a full or partial positive charge, and nucleophilic addition. Nucleophilicity is closely related to basicity. The difference between the two is, that basicity is a thermodynamic property (i.e. relates to an equilibrium state), but nucleop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Secondary Alcohols
In chemistry, an alcohol (), is a type of organic compound that carries at least one hydroxyl () functional group bound to a saturated carbon atom. Alcohols range from the simple, like methanol and ethanol, to complex, like sugar alcohols and cholesterol. The presence of an OH group strongly modifies the properties of hydrocarbons, conferring hydrophilic (water-loving) properties. The OH group provides a site at which many reactions can occur. History The flammable nature of the exhalations of wine was already known to ancient natural philosophers such as Aristotle (384–322 BCE), Theophrastus (–287 BCE), and Pliny the Elder (23/24–79 CE). However, this did not immediately lead to the isolation of alcohol, even despite the development of more advanced distillation techniques in second- and third-century Roman Egypt. An important recognition, first found in one of the writings attributed to Jābir ibn Ḥayyān (ninth century CE), was that by adding salt to boiling win ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tertiary Alcohols
In chemistry, an alcohol (), is a type of organic compound that carries at least one hydroxyl () functional group bound to a Saturated and unsaturated compounds, saturated carbon atom. Alcohols range from the simple, like methanol and ethanol, to complex, like sugar alcohols and cholesterol. The presence of an OH group strongly modifies the properties of Hydrocarbon, hydrocarbons, conferring Hydrophile, hydrophilic (water-loving) properties. The OH group provides a site at which many reactions can occur. History The flammable nature of the exhalations of wine was already known to ancient natural philosophers such as Aristotle (384–322 BCE), Theophrastus (–287 BCE), and Pliny the Elder (23/24–79 CE). However, this did not immediately lead to the isolation of alcohol, even despite the development of more advanced distillation techniques in second- and third-century Roman Egypt. An important recognition, first found in one of the writings attributed to Jabir ibn Hayyan, J� ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
