- Disposable cartridge concept for the on-demand synthesis of turbo Grignards, Knochel–Hauser amides, and magnesium alkoxides
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Magnesium organometallic reagents occupy a central position in organic synthesis. The freshness of these compounds is the key for achieving a high conversion and reproducible results. Common methods for the synthesis of Grignard reagents from metallic magnesium present safety issues and exhibit a batch-to-batch variability. Tubular reactors of solid reagents combined with solution-phase reagents enable the continuous-flow preparation of organomagnesium reagents. The use of stratified packed-bed columns of magnesium metal and lithium chloride for the synthesis of highly concentrated turbo Grignards is reported. A low-cost pod-style synthesizer prototype, which incorporates single-use prepacked perfluorinated cartridges and bags of reagents for the automated on-demand lab-scale synthesis of carbon, nitrogen, and oxygen turbo magnesium bases is presented. This concept will provide access to fresh organomagnesium reagents on a discovery scale and will do so independent from the operator’s experience in flow and/or organometallic chemistry.
- Adamo, Andrea,Berton, Mateo,McQuade, D. Tyler,Sheehan, Kevin
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supporting information
p. 1343 - 1356
(2020/07/10)
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- Electron-Catalyzed Coupling of Magnesium Amides with Aryl Iodides
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An electron was found to catalyze the coupling of magnesium diarylamides with aryl iodides giving triarylamines through a radical-anion intermediate. The transformation requires no transition metal catalysts or additives, and a wide array of products are formed in good-to-excellent yields.
- Kiriyama, Kazuya,Okura, Keisho,Tamakuni, Fumiko,Shirakawa, Eiji
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supporting information
p. 4519 - 4522
(2018/03/13)
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- PROCATALYST FOR POLYMERIZATION OF OLEFINS
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The present invention relates to a procatalyst comprising the compound represented by formula A as an internal electron donor, Formula A wherein R is hydrogen or a methyl group, N is nitrogen atom; O is oxygen atom; and C is carbon atom. The present invention also relates to a process for preparing said polymerization procatalyst and to a polymerization catalyst system comprising said procatalyst, a co-catalyst and optionally an external electron donor. Furthermore, the present invention relates to a polyolefin obtainable by the process according to the present invention and to the use of the compound of formula A as in internal electron donor in catalysts for polymerization of olefins.
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Page/Page column 23
(2018/06/16)
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- Association and Dissociation of Grignard Reagents RMgCl and Their Turbo Variant RMgC?LiCl
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Grignard reagents RMgCl and their so-called turbo variant, the highly reactive RMgC?LiCl, are of exceptional synthetic utility. Nevertheless, it is still not fully understood which species these compounds form in solution and, in particular, in which way LiCl exerts its reactivity-enhancing effect. A combination of electrospray-ionization mass spectrometry, electrical conductivity measurements, NMR spectroscopy (including diffusion-ordered spectroscopy), and quantum chemical calculations is used to analyze solutions of RMgCl (R=Me, Et, Bu, Hex, Oct, Dec, iPr, tBu, Ph) in tetrahydrofuran and other ethereal solvents in the absence and presence of stoichiometric amounts of LiCl. In tetrahydrofuran, RMgCl forms mononuclear species, which are converted into trinuclear anions as a result of the concentration increase experienced during the electrospray process. These trinuclear anions are theoretically predicted to adopt open cubic geometries, which remarkably resemble structural motifs previously found in the solid state. The molecular constituents of RMgCl and RMgC?LiCl are interrelated via Schlenk equilibria and fast intermolecular exchange processes. A small portion of the Grignard reagent also forms anionic ate complexes in solution. The abundance of these more electron-rich and hence supposedly more nucleophilic ate complexes strongly increases upon the addition of LiCl, thus rationalizing its beneficial effect on the reactivity of Grignard reagents.
- Schnegelsberg, Christoph,Bachmann, Sebastian,Kolter, Marlene,Auth, Thomas,John, Michael,Stalke, Dietmar,Koszinowski, Konrad
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supporting information
p. 7752 - 7762
(2016/06/08)
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- Catalyst system for polymerisation of an olefin
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The present invention relates to a catalyst system comprising a procatalyst, a co-catalyst and an external electron donor, wherein the external electron donor comprises a compound having the structure according to Formula I: ????????Si (L)n (OR1)4-n?????(Formula I), wherein, Si is a silicon atom with valency 4+; O is an oxygen atom with valency 2- and O is bonded to Si via the silicon-oxygen bond; n is 1, 2, 3 or 4; R1 is a selected from the group consisting of linear, branched and cyclic alkyl having at most 20 carbon atoms and aromatic substituted and unsubstituted hydrocarbyl having 6 to 20 carbon atoms; L is a group represented by Formula II wherein, L is bonded to the silicon atom via the nitrogen-silicon bond; L has a single substituent on the nitrogen atom, where this single substituent is an imine carbon atom; and X and Y are independently selected from the group consisting of a hydrogen atom; a heteroatom selected from group 13, 14, 15, 16 or 17 of the IUPAC Periodic Table of the Elements; a linear, branched and cyclic alkyl having at most 20 carbon atoms, optionally containing a heteroatom selected from group 13, 14, 15, 16 or 17 of the IUPAC Periodic Table of the Elements and an aromatic substituted and unsubstituted hydrocarbyl having 6 to 20 carbon atoms, optionally containing a heteroatom selected from group 13, 14, 15, 16 or 17 of the IUPAC Periodic Table of the Elements.
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Paragraph 0124
(2015/03/03)
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- Steric parameters for substituents bound to atoms of silicon and some other elements of the third period
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The kinetics of a tetraethoxysilane reaction with n-butylmagnesium chloride, stoichiometrically monosolvated with isopropyl ether or with methyl tert-butyl ether, was studied in toluene. The pseudo-first-order rate constants determined at a great excess of Grignard reagent were used for separation of the appropriate equilibrium and rate constants. Equilibrium constants for five alkyl ether ligands at the magnesium center are in an excellent correlation with isosteric ES(Si) parameters. It was concluded that these constants should be applicable to all elements of the third period of the periodic table. Taylor & Francis Group, LLC.
- Ploom, Anu,Tuulmets, Ants,Jaerv, Jaak
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experimental part
p. 2503 - 2510
(2011/02/25)
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- AMINOSILANE COMPOUNDS, CATALYST COMPONENTS AND CATALYSTS FOR OLEFIN POLYMERIZATION, AND PROCESS FOR PRODUCTION OF OLEFIN POLYMERS WITH THE SAME
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A catalyst for polymerization of olefins formed from (A) a solid catalyst component containing magnesium, titanium, halogen, and an electron donor compound, (B) an organoaluminum compound shown by the formula, R6pAlQ3-p, and (C) an aminosilane compound shown by the formula, R3nSi(NR4R5)4-n; and a process for producing a catalyst for polymerization of olefins in the presence of the catalyst are provided. A novel aminosilane compound, a catalyst component for polymerization of olefins having a high catalytic activity, capable of producing polymers with high stereoregularity in a high yield, and exhibiting an excellent hydrogen response, a catalyst, and a process for producing olefin polymers using the catalyst are provided.
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Page/Page column 18
(2010/11/30)
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- Method of preparation of an alkyne with an optically active hydroxyl group in the beta or gamma position of a triple bond and intermediates obtained
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The present invention relates to a method of preparation of an alkyne with an optically active hydroxyl group in the β or γ position of a triple bond and intermediates obtained. The method of the invention for preparation of an alkyne with an optically active hydroxyl group in the β position of a triple bond is characterized in that it comprises the reaction, in the presence of a Lewis acid: of a compound of formula (IV): in which: R is a linear or branched alkyl group having from 1 to 6 carbon atoms. and of a compound of formula (V): [in-line-formulae]R′—C≡C-M ??(V) [/in-line-formulae]in which: R′ represents a hydrogen atom, a linear or branched alkyl group having from 1 to 8 carbon atoms, preferably a methyl group or a trialkylsilyl group. M represents a metal, preferably a metal of group (Ia) of the periodic table, preferably lithium. Another object of the invention comprises the production of an alkyne with an optically active hydroxyl group in the γ position of a triple bond by isomerization of an alkyne with an optically active hydroxyl group in the β position previously obtained.
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Page/Page column 6-7
(2010/11/25)
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- PROCESS FOR PRODUCING PHOSPHONIUM BORATE COMPOUND, NOVEL PHOSPHONIUM BORATE COMPOUND, AND METHOD OF USING THE SAME
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The invention relates to a phosphonium borate compound represented by Formula (I) (hereinafter, the compound (I)). The invention has objects of providing (A) a novel process whereby the compound is produced safely on an industrial scale, by simple reaction operations and in a high yield; (B) a novel compound that is easily handled; and (C) novel use as catalyst. ????????Formula (I) : (R1)(R2)(R3)PH·BAr4?????(I) wherein R1, R2, R3 and Ar are as defined in the specification. The process (A) includes reacting a phosphine with a) HCl or b) H2SO4 to produce a) a hydrochloride or b) a sulfate; and reacting the salt with a tetraarylborate compound. The compound (B) has for example a secondary or tertiary alkyl group as R1 and is easily handled in air without special attention. The use (C) is characterized in that the compound (I) is used instead of an unstable phosphine compound of a transition metal complex catalyst for catalyzing C-C bond, C-N bond and C-O bond forming reactions and the compound produces an effect that is equal to that achieved by the transition metal complex catalyst.
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Page/Page column 89-90
(2008/06/13)
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- HALIDE REDUCTION DIHYDROCARBYLMAGNESIUM MIXTURES
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This invention provides a process for reducing the amount of soluble halide in a solution comprising a liquid organic medium, at least one viscosity reducing agent, at least one dihydrocarbylmagnesium compound, and an initial amount of soluble halide. The process comprises mixing at least one alkali metal with the solution at a mole ratio of alkali metal to magnesium of less than about 1:2.5, thereby forming precipitated soluble halides. Also provided by this invention is a process for reducing the amount of soluble halide in a slurry comprising a liquid organic medium, at least one viscosity reducing agent, at least one dihydrocarbylmagnesium compound, solids from the formation of said dihydrocarbylmagnesium compound, and an initial amount of soluble halide. This process comprises mixing at least one alkali metal with the slurry at a mole ratio of alkali metal to magnesium of less than about 1:1.25, thereby forming precipitated soluble halides.
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Page/Page column 21
(2008/06/13)
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- Absolute kinetic rate constants and activation energies for the formation of Grignard reagents
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This paper reports the first absolute rate constants for the formation of Grignard reagents from magnesium metal and organohalides. The theory that allows calculation of heterogeneous rate constants from the rate of growth of individual pits is described. By monitoring the reaction of individual reactive sites on the magnesium surface using photomicrography, it is possible to determine the rate of reaction and the active surface area; rate constants then are calculated from those data. Rate constants are on the order of 10-4 cm/s and vary relatively little between various organohalides. By measuring rate constants over a range of temperatures, Arrhenius parameters are determined for the reaction. The magnitudes of the enthalpic and entropic barriers are not consistent with electron transfer as the rate-limiting step. Rather, the data suggest that the rate-limiting step is reaction of the organohalide at the magnesium surface with partial insertion of a magnesium atom into the carbon-halide bond in the transition state.
- Beals, Bridget J.,Bello, Zainab I.,Cuddihy, Kathleen P.,Healy, Ethan M.,Koon-Church, Stephanie E.,Owens, Jane M.,Teerlinck, Cynthia E.,Bowyer, Walter J.
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p. 498 - 503
(2007/10/03)
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- Active Magnesium from Catalytically Prepared Magnesium Hydride or from Magnesium Anthracene and its Uses in the Synthesis
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Highly reactive, pyrophoric forms of magnesium with specific surface areas of 20-109 m2/g (Mg*) can be generated by the dehydrogenation of catalytically prepared magnesium hydride (MgH2*) or by decomposition of magnesium anthracene * 3 THF (4).The decomposition of 4, with recovery of anthracene and THF, may be accomplished both thermally and by ultrasound in an organic solvent (toluene, n-heptane) or thermally in the solid state in vacuo.Mg* obtained by the latter method exhibits only weak reflections in the X-ray powder diagram and has, in comparison to other mentioned Mg* species, the highest reactivity toward hydrogen.Diverse Grignard compounds can be prepared under mild conditions (* from MgH2* or 4.The cleavage of THF with formation of 1-oxa-2-magnesiacyclohexane (2) is possible by employing Mg* from NgH2* or 4.
- Bartmann, Ekkehard,Bogdanovic, Borislav,Janke, Nikolaus,Liao, Shijan,Schlichte, Klaus,et al.
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p. 1517 - 1528
(2007/10/02)
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- Process for preparation of asymmetric triorganotin halide
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A process for the preparation of an asymmetric triorganotin halide which is represented by the general formula [III] STR1 wherein R represents alkyl or phenyl, R* represents cyclohexyl or neophyl, and X represents a chlorine or bromine atom, which comprises reacting in the presence or absence of an inert organic solvent an asymmetric tetraorganotin compound of the general formula [I] STR2 with a tin (IV) halide of the general formula [II] in approximately equimolar amounts to yield a reaction mixture including compounds of the general formula of [III] and [IV] STR3 and subsequently, without the isolation of the asymmetric triorganotin halide [III], reacting the reaction mixture with substantially twice the molar amount, based on monoorganotin trihalide [IV], of an ether solution of organomagnesium halide of the general formula of [V]
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- Use of Magnesium Anthracene * 3 THF in Synthesis: Generation of Grignard Compounds and Other Reactions with Organic Halides
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The course (a), (b), (c) (Scheme 1) of the reaction of magnesium anthracene * 3 THF (1) with organic halides (RX) is dependent on the nature of RX.With alkyl halides in THF 1 reacts as a nucleophile, whereby primary as well as secondary alkyl halides produce dialkyldihydroanthracenes (4-4'') and tertiary alkyl halides yield primarily monoalkyl-substituted dihydroanthracenes (2, 2').With bromo- and iodobenzene in THF 1 reacts predominantly as a radical with H atom abstraction from the solvent affording benzene and 9.The formation of Grignard compounds (5) and anthracene (6), originating from primary and secondary alkyl and aryl halides and 1 in toluene or ether at elevated temperatures, is not caused by the reaction of 1 but by the "active magnesium" (Mg*) formed by decomposition of 1 in these solvents.In contrast, allyl, propargyl, and benzyl halides react with 1 independently of the solvent under mild conditions to produce 5 and 6.Allyl- and the difficultly accessible allenylmagnesium chloride can be prepared in THF at -78 and 0 deg C, respectively, from the corresponding halides and ordinary Mg powder via catalytic amounts of 1.
- Bogdanovic, Borislav,Janke, Nikolaus,Kinzelmann, Hans-Georg
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p. 1507 - 1515
(2007/10/02)
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