|
Triphenylphosphine Oxide
Triphenylphosphine oxide (often abbreviated TPPO) is the organophosphorus compound with the formula OP(C6H5)3, also written as Ph3PO or PPh3O (Ph = phenyl, C6H5). This colourless crystalline compound is a common but potentially useful waste product in reactions involving triphenylphosphine. It is a popular reagent to induce the crystallization, crystallizing of chemical compounds. Structure and properties Ph3PO is a tetrahedral molecule related to POCl3. The oxygen center is relatively basic. The rigidity of the backbone and the basicity of the oxygen center make this species a popular agent to crystallize otherwise difficult to crystallize molecules. This trick is applicable to molecules that have acidic hydrogen atoms, e.g. phenols. Up to now, several modifications of Ph3PO have been found: For example, a monoclinic form crystalizes in the space group ''P''21/''c'' with Z = 4 and a = 15.066(1) Å, b = 9.037(2) Å, c = 11.296(3) Å, and β = 98.47(1)°. The orthorhombic modif ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triphenylphosphine Sulfide
Triphenylphosphine sulfide (IUPAC name: triphenyl-''λ''5-phosphanethione) is the organophosphorus compound with the formula , usually written (where Ph = phenyl). It is a colourless solid, which is soluble in a variety of organic solvents. Structurally, the molecule resembles the corresponding oxide, with idealized C3 symmetry group, point group symmetry. It is weakly nucleophilic at the sulfur atom. Applications Organic synthesis Triphenylphosphine sulfide is useful for the conversion of epoxides to the corresponding episulfides: : Analytical chemistry In analytical chemistry, triphenylphosphine is used for the analysis of certain kinds of sulfur compounds. Elemental sulfur (), as occurs in some oils, and labile organosulfur compounds, such as organic trisulfides, react with triphenylphosphine to give , which can be detected by gas chromatography. References {{reflist Organophosphine sulfides Phenyl compounds ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mitsunobu Reaction
The Mitsunobu reaction is an organic reaction that converts an alcohol into a variety of functional groups, such as an ester, using triphenylphosphine and an azodicarboxylate such as diethyl azodicarboxylate (DEAD) or diisopropyl azodicarboxylate (DIAD). Although DEAD and DIAD are most commonly used, there are a variety of other azodicarboxylates available which facilitate an easier workup and/or purification and in some cases, facilitate the use of more basic nucleophiles. It was discovered by Oyo Mitsunobu (1934–2003). Typical protocol is to add the phosphine and azodicarboxylate together at −10 °C, typically in THF or toluene, until a white precipitate forms. This white, cloudy suspension is the ylide. Then a solution of the nucleophile and alcohol are added together and the reaction can be, and in many cases is, heated to reflux. The alcohol reacts with the phosphine to create a good leaving group then undergoes an inversion of stereochemistry in classic SN2 fashion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HSAB Concept
HSAB concept is a jargon for "hard and soft (Lewis) acids and bases". HSAB is widely used in chemistry for explaining stability of compounds, reaction mechanisms and pathways. It assigns the terms 'hard' or 'soft', and 'acid' or 'base' to chemical species. 'Hard' applies to species which are small, have high charge states (the charge criterion applies mainly to acids, to a lesser extent to bases), and are weakly polarizable. 'Soft' applies to species which are big, have low charge states and are strongly polarizable. The theory is used in contexts where a qualitative, rather than quantitative, description would help in understanding the predominant factors which drive chemical properties and reactions. This is especially so in transition metal chemistry, where numerous experiments have been done to determine the relative ordering of ligands and transition metal ions in terms of their hardness and softness. HSAB theory is also useful in predicting the products of metathesis rea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diethyl Ether
Diethyl ether, or simply ether, is an organic compound in the ether class with the formula , sometimes abbreviated as (see Pseudoelement symbols). It is a colourless, highly volatile, sweet-smelling ("ethereal odour"), extremely flammable liquid. It is commonly used as a solvent in laboratories and as a starting fluid for some engines. It was formerly used as a general anesthetic, until non-flammable drugs were developed, such as halothane. It has been used as a recreational drug to cause intoxication. Production Most diethyl ether is produced as a byproduct of the vapor-phase hydration of ethylene to make ethanol. This process uses solid-supported phosphoric acid catalysts and can be adjusted to make more ether if the need arises. Vapor-phase dehydration of ethanol over some alumina catalysts can give diethyl ether yields of up to 95%. Diethyl ether can be prepared both in laboratories and on an industrial scale by the acid ether synthesis. Ethanol is mixed with a stro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexane
Hexane () is an organic compound, a straight-chain alkane with six carbon atoms and has the molecular formula C6H14. It is a colorless liquid, odorless when pure, and with boiling points approximately . It is widely used as a cheap, relatively safe, largely unreactive, and easily evaporated non-polar solvent, and modern gasoline blends contain about 3% hexane. The term ''hexanes'' refers to a mixture, composed largely (>60%) of hexane, with varying amounts of the isomeric compounds 2-methylpentane and 3-methylpentane, and, possibly, smaller amounts of nonisomeric C5, C6, and C7 (cyclo)alkanes. These ''hexanes'' are cheaper than pure hexane and are often used in large-scale operations not requiring a single isomer (e.g., as cleaning solvent or for chromatography). Isomers Uses In industry, hexanes are used in the formulation of adhesive, glues for shoes, leather products, and roofing. They are also used to extract cooking oils (such as canola oil or soy oil) from seeds, for c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trichlorosilane
Trichlorosilane is an inorganic compound with the formula HCl3Si. It is a colourless, volatile liquid. Purified trichlorosilane is the principal precursor to ultrapure silicon in the semiconductor industry. In water, it rapidly decomposes to produce a siloxane polymer while giving off hydrochloric acid. Because of its reactivity and wide availability, it is frequently used in the synthesis of silicon-containing organic compounds. Production Trichlorosilane is produced by treating powdered metallurgical grade silicon with blowing hydrogen chloride at 300 °C. Hydrogen is also produced, as described in the chemical equation: :Si + 3 HCl → HCl3Si + H2 Yields of 80-90% can be achieved. The main byproducts are silicon tetrachloride (chemical formula SiCl4), hexachlorodisilane (Si2Cl6) and dichlorosilane (H2SiCl2), from which trichlorosilane can be separated by distillation. It is also produced from silicon tetrachloride: :Si + 3 SiCl4 + 2 H2 → 4 HCl3Si Application ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosgene
Phosgene is the organic chemical compound with the formula COCl2. It is a toxic, colorless gas; in low concentrations, its musty odor resembles that of freshly cut hay or grass. Phosgene is a valued and important industrial building block, especially for the production of precursors of polyurethanes and polycarbonate plastics. Phosgene is extremely poisonous and was used as a chemical weapon during World War I, where it was responsible for 85,000 deaths. It was a highly potent pulmonary irritant and quickly filled enemy trenches due to it being a heavy gas. It is classified as a Schedule 3 substance under the Chemical Weapons Convention. In addition to its industrial production, small amounts occur from the breakdown and the combustion of organochlorine compounds, such as chloroform. Structure and basic properties Phosgene is a planar molecule as predicted by VSEPR theory. The C=O distance is 1.18 Å, the C−Cl distance is 1.74 Å and the Cl−C−Cl angle is 111 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alcohol (chemistry)
In chemistry, an alcohol is a type of organic compound that carries at least one hydroxyl () functional group bound to a saturated carbon atom. The term ''alcohol'' originally referred to the primary alcohol ethanol (ethyl alcohol), which is used as a drug and is the main alcohol present in alcoholic drinks. An important class of alcohols, of which methanol and ethanol are the simplest examples, includes all compounds which conform to the general formula . Simple monoalcohols that are the subject of this article include primary (), secondary () and tertiary () alcohols. The suffix ''-ol'' appears in the IUPAC chemical name of all substances where the hydroxyl group is the functional group with the highest priority. When a higher priority group is present in the compound, the prefix ''hydroxy-'' is used in its IUPAC name. The suffix ''-ol'' in non-IUPAC names (such as paracetamol or cholesterol) also typically indicates that the substance is an alcohol. However, some compou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Staudinger Reaction
The Staudinger reaction is a chemical reaction of an organic azide with a phosphine or phosphite produces an iminophosphorane. The reaction was discovered by and named after Hermann Staudinger. The reaction follows this stoichiometry: :R3P + R'N3 → R3P=NR' + N2 Staudinger reduction The Staudinger reduction is conducted in two steps. First phosphine imine-forming reaction is conducted involving treatment of the azide with the phosphine. The intermediate, e.g. triphenylphosphine phenylimide, is then subjected to hydrolysis to produce a phosphine oxide and an amine: :R3P=NR' + H2O → R3P=O + R'NH2 The overall conversion is a mild method of reducing an azide to an amine. Triphenylphosphine or tributylphosphine are most commonly used, yielding tributylphosphine oxide or triphenylphosphine oxide as a side product in addition to the desired amine. An example of a Staudinger reduction is the organic synthesis of the pinwheel compound 1,3,5-tris(aminomethyl)-2,4,6-triethylbenz ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triphenylphosphine
Triphenylphosphine (IUPAC name: triphenylphosphane) is a common organophosphorus compound with the formula P(C6H5)3 and often abbreviated to P Ph3 or Ph3P. It is widely used in the synthesis of organic and organometallic compounds. PPh3 exists as relatively air stable, colorless crystals at room temperature. It dissolves in non-polar organic solvents such as benzene and diethyl ether. Preparation and structure Triphenylphosphine can be prepared in the laboratory by treatment of phosphorus trichloride with phenylmagnesium bromide or phenyllithium. The industrial synthesis involves the reaction between phosphorus trichloride, chlorobenzene, and sodium: :PCl3 + 3 PhCl + 6 Na → PPh3 + 6 NaCl Triphenylphosphine crystallizes in triclinic and monoclinic modification. In both cases, the molecule adopts a pyramidal structure with propeller-like arrangement of the three phenyl groups. Principal reactions with chalcogens, halogens, and acids Oxidation Triphenylphosphine undergoes slow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
nickel(II)-from-xtal-3D-balls.png "Click for more on -> Triphenylphosphine Oxide")
