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Diazald
Diazald (''N''-methyl-''N''-nitroso-''p''-toluenesulfonamide) is used as a relatively safe and easily handled precursor to diazomethane, which is toxic and unstable. Diazald has become the favored commercially available precursor for the synthesis of diazomethane, compared to reagents like ''N''-methyl''-N-''nitrosourea and ''N-''methyl-''N'''-nitro-''N-''nitrosoguanidine, which are less thermally stable and more toxic and mutagenic, respectively. Upon the addition of a base such as sodium hydroxide or potassium hydroxide and mild heating (65–70 °C) in a mixture of water, diethyl ether, and a high boiling polar cosolvent (e.g., diethylene glycol monomethyl ether), the ''N-''nitrososulfonamide undergoes successive elimination reactions to produce diazomethane (which is codistilled as an ethereal solution) as well as a ''p''-toluenesulfonate salt as a byproduct, according to the following mechanism: Like other nitroso In organic chemistry, nitroso refers to a functiona ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diazomethane
Diazomethane is the chemical compound CH2N2, discovered by German chemist Hans von Pechmann in 1894. It is the simplest diazo compound. In the pure form at room temperature, it is an extremely sensitive explosive yellow gas; thus, it is almost universally used as a solution in diethyl ether. The compound is a popular methylating agent in the laboratory, but it is too hazardous to be employed on an industrial scale without special precautions. Use of diazomethane has been significantly reduced by the introduction of the safer and equivalent reagent trimethylsilyldiazomethane. Use For safety and convenience diazomethane is always prepared as needed as a solution in ether and used as such. It converts carboxylic acids to methyl esters and phenols into their methyl ethers. The reaction is thought to proceed via proton transfer from carboxylic acid to diazomethane to give methyldiazonium cation, which reacts with the carboxylate ion to give the methyl ester and nitrogen gas. Label ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N-Nitroso-N-methylurea
''N''-Nitroso-''N''-methylurea (NMU) is a highly reliable carcinogen, mutagen, and teratogen. NMU is an alkylating agent, and exhibits its toxicity by transferring its methyl group to nucleobases in nucleic acids, which can lead to AT:GC transition mutations. NMU is the traditional precursor in the synthesis of diazomethane. It has the potentially advantageous property that the stoichiometric byproducts formed are water, carbon dioxide, and ammonia, which are innocuous or easily removed. However, because it is unstable at temperatures beyond 20 °C and somewhat shock-sensitive, it has become obsolete for this purpose and replaced by other N-nitroso compounds: (''N''-methyl)nitrosamides and nitrosamines. Most chemical supply houses have stopped carrying it. Acute exposure to NMU in humans can result in skin and eye irritation, headache, nausea, and vomiting. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methylnitronitrosoguanidine
Methylnitronitrosoguanidine (MNNG or MNG, NTG when referred to colloquially as nitrosoguanidine) is a biochemical tool used experimentally as a carcinogen and mutagen. It acts by adding alkyl groups to the O6 of guanine and O4 of thymine, which can lead to transition mutations between GC and AT. These changes do not cause a heavy distortion in the double helix of DNA and thus are hard to detect by the DNA mismatch repair system. One of the earliest uses of methylnitronitrosoguanidine was in 1985. A group of scientists tested whether or not the chemical composition of methylnitronitrosoguanidine would directly affect the growth of tumors and cancer cells in rats. In the experiment, the cancer cells from a Japanese cancer patient was injected into 8 rats. The biochemical tool and showed a decline of cancer cells in a few of the rats' bodies. In organic chemistry, MNNG is used as a source of diazomethane when reacted with aqueous potassium hydroxide. MNNG is a probable human carci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Base (chemistry)
In chemistry, there are three definitions in common use of the word base, known as Arrhenius bases, Brønsted bases, and Lewis bases. All definitions agree that bases are substances that react with acids, as originally proposed by G.-F. Rouelle in the mid-18th century. In 1884, Svante Arrhenius proposed that a base is a substance which dissociates in aqueous solution to form Hydroxide ions OH−. These ions can react with hydrogen ions (H+ according to Arrhenius) from the dissociation of acids to form water in an acid–base reaction An acid–base reaction is a chemical reaction that occurs between an acid and a base. It can be used to determine pH via titration. Several theoretical frameworks provide alternative conceptions of the reaction mechanisms and their applica .... A base was therefore a metal hydroxide such as Sodium hydroxide, NaOH or Calcium hydroxide, Ca(OH)2. Such aqueous hydroxide solutions were also described by certain characteristic properties. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Hydroxide
Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula NaOH. It is a white solid ionic compound consisting of sodium cations and hydroxide anions . Sodium hydroxide is a highly caustic base and alkali that decomposes proteins at ordinary ambient temperatures and may cause severe chemical burns. It is highly soluble in water, and readily absorbs moisture and carbon dioxide from the air. It forms a series of hydrates . The monohydrate crystallizes from water solutions between 12.3 and 61.8 °C. The commercially available "sodium hydroxide" is often this monohydrate, and published data may refer to it instead of the anhydrous compound. As one of the simplest hydroxides, sodium hydroxide is frequently used alongside neutral water and acidic hydrochloric acid to demonstrate the pH scale to chemistry students. Sodium hydroxide is used in many industries: in the manufacture of pulp and paper, textiles, drinking water, soaps and deterge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potassium Hydroxide
Potassium hydroxide is an inorganic compound with the formula K OH, and is commonly called caustic potash. Along with sodium hydroxide (NaOH), KOH is a prototypical strong base. It has many industrial and niche applications, most of which exploit its caustic nature and its reactivity toward acids. An estimated 700,000 to 800,000 tonnes were produced in 2005. KOH is noteworthy as the precursor to most soft and liquid soaps, as well as numerous potassium-containing chemicals. It is a white solid that is dangerously corrosive. Properties and structure KOH exhibits high thermal stability. Because of this high stability and relatively low melting point, it is often melt-cast as pellets or rods, forms that have low surface area and convenient handling properties. These pellets become tacky in air because KOH is hygroscopic. Most commercial samples are ca. 90% pure, the remainder being water and carbonates. Its dissolution in water is strongly exothermic. Concentrated aqueous solut ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2-(2-Methoxyethoxy)ethanol
2-(2-Methoxyethoxy)ethanol, also known under trade names Methyl carbitol, is an industrial solvent and is also commonly used as a fuel system icing inhibitor (FSII) in jet fuels. It is a clear, colorless, hygroscopic liquid. Structurally it is an alcohol and an ether, with a formula CH3OCH2CH2OCH2CH2OH. At direct contact it causes drying of skin by leaching fats, and is mildly irritating to the eyes. It is flammable. See also * Cellosolve * 2-Ethoxyethanol External links Methyl Carbitol Technical Data Sheet, Dow Chemical Company The Dow Chemical Company, officially Dow Inc., is an American multinational chemical corporation headquartered in Midland, Michigan, United States. The company is among the three largest chemical producers in the world. Dow manufactures plastic ... {{DEFAULTSORT:Methoxyethoxyethanol, 2-(2- Primary alcohols Glycol ethers Alcohol solvents Ether solvents ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
P-Toluenesulfonic Acid
''p''-Toluenesulfonic acid (PTSA or ''p''TsOH) or tosylic acid (TsOH) is an organic compound with the formula CH3 C6H4 SO3H. It is a white extremely hygroscopic solid that is soluble in water, alcohols, and other polar organic solvents. The CH3C6H4SO2 group is known as the tosyl group and is often abbreviated as Ts or Tos. Most often, TsOH refers to the monohydrate, TsOH.H2O. As with other aryl sulfonic acids, TsOH is a strong organic acid. It is about one million times stronger than benzoic acid. It is one of the few strong acids that is solid and therefore is conveniently weighed and stored. Preparation and uses TsOH is prepared on an industrial scale by the sulfonation of toluene. Common impurities include benzenesulfonic acid and sulfuric acid. TsOH monohydrate contains an amount of water. To estimate the total moisture present as impurity, the Karl Fischer method is used. Impurities can be removed by recrystallization from its concentrated aqueous solution followed by az ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitroso
In organic chemistry, nitroso refers to a functional group in which the nitric oxide () group is attached to an organic moiety. As such, various nitroso groups can be categorized as ''C''-nitroso compounds (e.g., nitrosoalkanes; ), ''S''-nitroso compounds ( nitrosothiols; ), ''N''-nitroso compounds (e.g., nitrosamines, ), and ''O''-nitroso compounds ( alkyl nitrites; ). Synthesis Nitroso compounds can be prepared by the reduction of nitro compounds or by the oxidation of hydroxylamines. Ortho-nitrosophenols may be produced by the Baudisch reaction. In the Fischer–Hepp rearrangement aromatic 4-nitrosoanilines are prepared from the corresponding nitrosamines. Properties Nitrosoarenes typically participate in a monomer–dimer equilibrium. The dimers, which are often pale yellow, are often favored in the solid state, whereas the deep-green monomers are favored in dilute solution or at higher temperatures. They exist as ''cis'' and ''trans'' isomers. Due to the stability o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfonamides
In organic chemistry, the sulfonamide functional group (also spelled sulphonamide) is an organosulfur group with the structure . It consists of a sulfonyl group () connected to an amine group (). Relatively speaking this group is unreactive. Because of the rigidity of the functional group, sulfonamides are typically crystalline; for this reason, the formation of a sulfonamide is a classic method to convert an amine into a crystalline derivative which can be identified by its melting point. Many important drugs contain the sulfonamide group. A sulfonamide (compound) is a chemical compound that contains this group. The general formula is or , where each R is some organic group; for example, "methanesulfonamide" (where R = methane, R' = R" = hydrogen) is . Any sulfonamide can be considered as derived from a sulfonic acid by replacing a hydroxyl group () with an amine group. In medicine, the term "sulfonamide" is sometimes used as a synonym for sulfa drug, a derivative or var ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitroso Compounds
In organic chemistry, nitroso refers to a functional group in which the nitric oxide () group is attached to an organic moiety. As such, various nitroso groups can be categorized as ''C''-nitroso compounds (e.g., nitrosoalkanes; ), ''S''-nitroso compounds ( nitrosothiols; ), ''N''-nitroso compounds (e.g., nitrosamines, ), and ''O''-nitroso compounds ( alkyl nitrites; ). Synthesis Nitroso compounds can be prepared by the reduction of nitro compounds or by the oxidation of hydroxylamines. Ortho-nitrosophenols may be produced by the Baudisch reaction. In the Fischer–Hepp rearrangement aromatic 4-nitrosoanilines are prepared from the corresponding nitrosamines. Properties Nitrosoarenes typically participate in a monomer–dimer equilibrium. The dimers, which are often pale yellow, are often favored in the solid state, whereas the deep-green monomers are favored in dilute solution or at higher temperatures. They exist as ''cis'' and ''trans'' isomers. Due to the stability o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
