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Trithioacetone
Trithioacetone (2,2,4,4,6,6-hexamethyl-1,3,5-trithiane) is an organic chemical with chemical formula, formula . Its Covalent bond, covalent structure is , that is, a six-membered ring of alternating carbon and sulfur atoms, with two methyl groups attached to each carbon. It can be viewed as a derivative of 1,3,5-trithiane, with methyl-group substituents for all of the hydrogen atoms in that parent structure. The compound Trithioacetone is a stable cyclic compound, cyclic trimer of thioacetone (propane-2-thione), which by itself is an unstable compound. In contrast, the analogous 1,3,5-trioxane, trioxane compound, 2,2,4,4,6,6-hexamethyl-1,3,5-trioxane (Triacetone), with oxygen atoms in place of the sulfur atoms, seems to be unstable, while its corresponding monomer acetone (2-propanone) is stable. Synthesis Trithioacetone was first made in 1889 by Baumann and Fromm, by reaction of hydrogen sulfide with acetone. In the presence of an acidified catalyst at 25 °C, one obtains ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thioacetone
Thioacetone is an organosulfur compound belonging to the -thione group called thioketones, with a chemical formula (CH3)2CS. It is an unstable orange or brown substance that can be isolated only at low temperatures. Above , thioacetone readily converts to a polymer and a trimer, trithioacetone. It has an extremely potent, unpleasant odor, and is considered one of the worst-smelling chemicals known. Thioacetone was first obtained in 1889 by Baumann and Fromm, as a minor impurity in their synthesis of trithioacetone.William H. Sharkey (1979): "Polymerization through the carbon-sulfur double bond". ''Polymerization'', series ''Advances in Polymer Science'', volume 17, pages 73-103. Preparation Thioacetone is usually obtained by cracking the cyclic trimer trithioacetone, CH3)2CSsub>3. The trimer is prepared by pyrolysis of allyl isopropyl sulfide or by treating acetone with hydrogen sulfide in the presence of a Lewis acid. The trimer cracks at to give the thione. : Polymeri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acetone
Acetone (2-propanone or dimethyl ketone), is an organic compound with the formula . It is the simplest and smallest ketone (). It is a colorless, highly volatile and flammable liquid with a characteristic pungent odour. Acetone is miscible with water and serves as an important organic solvent in its own right, in industry, home, and laboratory. About 6.7 million tonnes were produced worldwide in 2010, mainly for use as a solvent and production of methyl methacrylate (and from that PMMA) as well as bisphenol A.Acetone World Petrochemicals report, January 2010Stylianos Sifniades, Alan B. Levy, "Acetone" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005. It is a common building block in |
Organic Chemical
In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The study of the properties, reactions, and syntheses of organic compounds comprise the discipline known as organic chemistry. For historical reasons, a few classes of carbon-containing compounds (e.g., carbonate salts and cyanide salts), along with a few other exceptions (e.g., carbon dioxide, hydrogen cyanide), are not classified as organic compounds and are considered inorganic. Other than those just named, little consensus exists among chemists on precisely which carbon-containing compounds are excluded, making any rigorous definition of an organic compound elusive. Although organic compounds make up only a small percentage of Earth's crust, they are of central importance because all known life is based on organic compounds. Living thing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyrolysis
The pyrolysis (or devolatilization) process is the thermal decomposition of materials at elevated temperatures, often in an inert atmosphere. It involves a change of chemical composition. The word is coined from the Greek-derived elements ''pyro'' "fire", "heat", "fever" and '' lysis'' "separating". Pyrolysis is most commonly used in the treatment of organic materials. It is one of the processes involved in charring wood.''Burning of wood'' , InnoFireWood's website. Accessed on 2010-02-06. In general, pyrolysis of organic substances produces volatile products and leaves , a carbon-rich solid residue. Extreme pyrolysis, which leaves mostly |
2,2,4,4,6,6-hexamethyl-1,3,5-triselena-2,4,6-tristannacyclohexane
The comma is a punctuation mark that appears in several variants in different languages. It has the same shape as an apostrophe or single closing quotation mark () in many typefaces, but it differs from them in being placed on the baseline of the text. Some typefaces render it as a small line, slightly curved or straight, but inclined from the vertical. Other fonts give it the appearance of a miniature filled-in figure on the baseline. The comma is used in many contexts and languages, mainly to separate parts of a sentence such as clauses, and items in lists mainly when there are three or more items listed. The word ''comma'' comes from the Greek (), which originally meant a cut-off piece, specifically in grammar, a short clause. A comma-shaped mark is used as a diacritic in several writing systems and is considered distinct from the cedilla. In Byzantine and modern copies of Ancient Greek, the "rough" and "smooth breathings" () appear above the letter. In Latvian, Ro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrogen
Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at seventh in total abundance in the Milky Way and the Solar System. At standard temperature and pressure, two atoms of the element bond to form N2, a colorless and odorless diatomic gas. N2 forms about 78% of Earth's atmosphere, making it the most abundant uncombined element. Nitrogen occurs in all organisms, primarily in amino acids (and thus proteins), in the nucleic acids ( DNA and RNA) and in the energy transfer molecule adenosine triphosphate. The human body contains about 3% nitrogen by mass, the fourth most abundant element in the body after oxygen, carbon, and hydrogen. The nitrogen cycle describes the movement of the element from the air, into the biosphere and organic compounds, then back into the atmosphere. Many indus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexamethylcyclotrisilazane
Hexamethylcyclotrisilazane is a chemical compound with formula or . Its molecule consists of a six-member ring of three silicon atoms alternating with three nitrogen atoms, with two methyl groups bonded to each silicon and one hydrogen atom bonded to each nitrogen. It can be described as a derivative of the hypothetical compound cyclotrisilazane , or as a cyclic trimer of hypothetical dimethylsilazane . The compound is a clear colorless liquid at room temperature. The compound has been extensively studied because of its applications in the semiconductor industry, as a precursor for the deposition of fils of silicon nitride and silicon carbonitride and as an additive in photoresist formulations. It has also been proposed as an additive to silica for liquid chromatography. Other names for the compound are 2,2,4,4,6,6-hexamethyl-1,3,5,2,4,6-triazatrisilinane (IUPAC), 1,1,3,3,5,5-hexamethyl-2,4,6,1,3,5-triazatrisilinane, and 2,4,4,6,6-hexamethyl-1,3,5-triaza-2,4,6-trisilacyc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silicon
Silicon is a chemical element with the symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic luster, and is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic table: carbon is above it; and germanium, tin, lead, and flerovium are below it. It is relatively unreactive. Because of its high chemical affinity for oxygen, it was not until 1823 that Jöns Jakob Berzelius was first able to prepare it and characterize it in pure form. Its oxides form a family of anions known as silicates. Its melting and boiling points of 1414 °C and 3265 °C, respectively, are the second highest among all the metalloids and nonmetals, being surpassed only by boron. Silicon is the eighth most common element in the universe by mass, but very rarely occurs as the pure element in the Earth's crust. It is widely distributed in space in cosmic dusts, planetoids, and planets as various forms of silicon dioxide ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexamethylcyclotrisiloxane
Hexamethylcyclotrisiloxane, also known as D3 and D3, is the organosilicon compound with the formula . It is a colorless or white volatile solid. It finds limited use in organic chemistry. The larger tetrameric and pentameric siloxanes, respectively octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane, are of significant industrial interest, whereas 1,000–10,000 tonnes per year of the trimer is manufactured and/or imported in the European Economic Area. Structure and reactions Hexamethylcyclotrisiloxane adopts a planar structure and is considered strained. It reacts with organolithium reagents to give, after hydrolysis, dimethylsilanols: : : Safety and environmental considerations The LD50 for the related pentamer (D5) is >50 g/kg in rats. See also * Octamethylcyclotetrasiloxane (D4) * Decamethylcyclopentasiloxane Decamethylcyclopentasiloxane, also known as D5 and D5, is an organosilicon compound with the formula . It is a colorless and odorless liquid that is sli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lethal Dose
In toxicology, the lethal dose (LD) is an indication of the lethal toxicity of a given substance or type of radiation. Because resistance varies from one individual to another, the "lethal dose" represents a dose (usually recorded as dose per kilogram of subject body weight) at which a given ''percentage'' of subjects will die. The lethal concentration is a lethal dose measurement used for gases or particulates. The LD may be based on the standard person concept, a theoretical individual that has perfectly "normal" characteristics, and thus not apply to all sub-populations. Median lethal dose (LD50) The median lethal dose, LD50 (abbreviation for "lethal dose, 50%"), LC50 (lethal concentration, 50%) or LCt50 (lethal concentration and time) of a toxin, radiation, or pathogen is the dose required to kill half the members of a tested population after a specified test duration. LD50 figures are frequently used as a general indicator of a substance's acute toxicity. A lower LD50 is indi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flavor And Extract Manufacturers Association
The Flavor and Extract Manufacturers Association (FEMA) is a food industry trade group based in the United States. FEMA was founded in 1909 by several flavor firms in response to the passage of the Pure Food and Drug Act of 1906. Founding members were McCormick & Company, Ulman Driefus & Company, Jones Brothers, Blanke Baer Chemical Company, Frank Tea & Spice Company, Foote & Jenkes, Sherer Gillett Company, and C.F. Sauer Company. Since its founding, FEMA has played instrumental roles in creating a program to assess the safety and " generally recognized as safe" status of flavor ingredients, advocating for policies that positively impact the food and flavor industry, and in representing its members' interests during the creation of the Food Additives Amendment of 1958, an amendment to the United States' Food, Drugs, and Cosmetic Act of 1938. FEMA maintains a Flavor Ingredient Library, a list of all flavoring ingredients allowed in the United States. Critics of FEMA have said th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
