- Synthesis and transformation of metallacycles 25.* On a mechanism of the Ni(acac)2-catalyzed converson of 3-alkyl-1-ethylalumacyclopentanes into 1,1-disubstituted cyclopropanes
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The reactions of 3-alkyl-1-ethylalumacyclopentanes with allyl halides in the presence of Ni(acac)2 as a catalyst were studied by dynamic NMR spectroscopy. Under the action of Ni complexes, alumacyclopentanes initially undergo intramolecular hydride transfer to give but-3-enyl(ethyl)aluminum hydrides and then react with the starting allyl halide, yielding but-3-enyl(ethyl)aluminum halides. Subsequent intramolecular carboalumination affords the corresponding 1,1-disubstituted cyclopropanes.
- Dzhemilev,Ibragimov,Khafizova,Parfenova,Yalalova,Khalilov
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Read Online
- 'One-pot' synthesis of 1,1-disubstituted cyclopropanes in the presence of metal complex catalysts
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A 'one-pot' catalytic method for the synthesis of 1,1-disubstituted cyclopropanes starting from olefins, acetylenes and AlEt3 in the presence of Cp2ZrCl2, via a step involving in situ formation of aluminacyclopentanes and aluminacyclopentenes, respectively, was developed. Five-membered organoaluminium compounds obtained without preliminary isolation are transformed to cyclopropanes under the effect of Ni(acac)2 in combination with allylhalogenides in the case of aluminacyclopentanes and alkylsulphates in experiments with aluminacyclopentenes.
- Dzhemilev, Usein M.,Ibragimov, Askhat G.,Khafizova, Leyla O.,Ramazanov, Ilfir R.,Yalalova, Dina F.,Tolstikov, Genrikh A.
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Read Online
- Elongation and branching of a-olefins by two ethylene molecules
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a-Olefins are important starting materials for the production of plastics, pharmaceuticals, and fine and bulk chemicals. However, the selective synthesis of a-olefins from ethylene, a highly abundant and inexpensive feedstock, is restricted, and thus a broadly applicable selective a-olefin synthesis using ethylene is highly desirable. Here, we report the catalytic reaction of an a-olefin with two ethylene molecules. The first ethylene molecule forms a 4-ethyl branch and the second a new terminal carbon-carbon double bond (C2 elongation). The key to this reaction is the development of a highly active and stable molecular titanium catalyst that undergoes extremely fast b-hydride elimination and transfer.
- Dietel, Thomas,Lukas, Fabian,Kretschmer, Winfried P.,Kempe, Rhett
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p. 1021 - 1024
(2022/03/15)
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- Renewable plasticizer alcohols from olefin oligomers and methods for making the same
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An efficient, low-temperature process to convert well-defined olefin oligomers, particularly butene oligomers to branched chain alcohols suitable for use as precursors to plasticizers commonly used in industry, and more specifically, the olefin feedstocks can be conveniently and renewably produced from short chain alcohols.
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Page/Page column 5
(2018/04/20)
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- Thermally induced structural transformations of linear coordination polymers based on aluminum tris(diorganophosphates)
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The thermal transitions of inorganic-organic hybrid polymers composed of linear aluminum tris(diorganophosphate) chains with a general formula of catena-Al[O2P(OR)2]3 (where R = C1-C8 alkyl group or phenyl moiety) have been studied by means of DSC, powder XRD, TGA and TG-QMS, as well as optical spectroscopy. DSC and XRD reveal that most of them undergo reversible structural transformations in the solid state between ?100 and 200 °C caused by the changes in conformation of their organic substituents; however, a translational displacement of the rigid polymeric chains occurs only in the case of the derivative bearing long 2-ethylhexyl groups, which becomes liquid at about 140 °C. The thermal decomposition of the studied polymers begins between 200 and 265 °C depending on the type of organic substituent R decorating their aluminophospate core. TGA combined with mass spectrometry of the evolved gaseous products shows that the pyrolytic decomposition of Al[O2P(OR)2]3 proceeds either through β-elimination of olefin (for compounds with C2-C8 aliphatic ligands), or a homolytic cleavage of the P-OR bond (for methyl and phenyl derivatives); both processes are accompanied by condensation of the newly formed POH groups and liberation of water. Powder XRD, FTIR and SEM analyses of the solid residues indicate that thermolysis of Al[O2P(OR)2]3 accompanied by olefin elimination leads to the formation of condensed aluminum phosphates, mainly aluminum cyclohexaphosphate, exhibiting porous morphology. On the other hand, thermal degradation of methyl or phenyl derivatives results in amorphous aluminophosphate residues, and the latter contains conducting carbonaceous phases.
- D?bowski, Maciej,?okaj, Krzysztof,Ostrowski, Andrzej,Zachara, Janusz,Wiecińska, Paulina,Falkowski, Pawe?,Krztoń-Maziopa, Anna,Florjańczyk, Zbigniew
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supporting information
p. 16480 - 16491
(2018/12/05)
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- Effect of Alcohol Structure on the Kinetics of Etherification and Dehydration over Tungstated Zirconia
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Linear and branched ether molecules have attracted recent interest as diesel additives and lubricants that can be produced from biomass-derived alcohols. In this study, tungstated zirconia was identified as a selective and green solid acid catalyst for the direct etherification of primary alcohols in the liquid phase, achieving ether selectivities of >94 % for C6–C12 linear alcohol coupling at 393 K. The length of linear primary alcohols (C6–C12) was shown to have a negligible effect on apparent activation energies for etherification and dehydration, demonstrating the possibility to produce both symmetrical and asymmetrical linear ethers. Reactions over a series of C6 alcohols with varying methyl branch positions indicated that substituted alcohols (2°, 3°) and alcohols with branches on the β-carbon readily undergo dehydration, but alcohols with branches at least three carbons away from the -OH group are highly selective to ether. A novel model compound, 4-hexyl-1dodecanol, was synthesized and tested to further demonstrate this structure–activity relationship. Trends in the effects of alcohol structure on selectivity were consistent with previously proposed mechanisms for etherification and dehydration, and help to define possible pathways to selectively form ethers from biomass-derived alcohols.
- Rorrer, Julie,Pindi, Suresh,Toste, F. Dean,Bell, Alexis T.
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p. 3104 - 3111
(2018/09/06)
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- DIARYL AMINE ANTIOXIDANTS PREPARED FROM BRANCHED OLEFINS
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Diaryl amines are selectively alkylated by reaction with branched olefins, which olefins are capable of forming tertiary carbonium ions and can be conveniently prepared from readily available branched alcohols. The diaryl amine products are effective antioxidants and often comprise a high amount of di-alkylated diaryl amines and a low amount of tri- and tetra-alkylated diaryl amines.
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Paragraph 0058; 0059
(2017/02/09)
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- Oligomerization of 1-butene with a homogeneous catalyst system based on allylic nickel complexes
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The oligomerization of 1-butene with a nickel-based catalyst system constitutes an elegant synthesis method for obtaining linear octenes from readily available chemicals. It is well known that the bis-(cyclooctadiene)nickel(0)-complex (Ni(COD)2) can be used in combination with 1,1,1,5,5,5-hexafluoroacetylacetone (hfacac) forming [Ni-1] as a catalyst for the dimerization of 1-butene, which produces a linear octene yield of 75-83% at reaction temperatures between 70-80 °C. We are the first to demonstrate that it is also possible to use allylic nickel complexes in combination with hfacac to produce linear octenes with a selectivity of 70% under very mild reaction conditions and at low catalyst concentrations. Additionally the catalyst can be formed simply by adding the activator hfacac to a solution of the allylic nickel complex. No complicated synthesis or purification is needed.
- Behr,Bayrak,Peitz,Stochniol,Maschmeyer
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p. 41372 - 41376
(2015/05/27)
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- Isononylamines from 2-Ethylhexanol, Processes for Their Preparation, and Their Use
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Process for preparing isononylamines starting out from 2-ethylhexanol, characterized in that (a) 2-ethylhexanol is dehydrated in the presence of a catalyst to form octene; (b) the octene obtained in step a) is reacted with carbon monoxide and hydrogen in the presence of a transition metal compound of group VIII of the Periodic Table of the Elements to form isononanal; and (c) the isononanal obtained in step b) is converted into isononylamines.
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Paragraph 0056-0057
(2015/06/10)
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- Vinyl Esters of Isononanoic Acid Starting from 2-Ethyl Hexanol, Methods for the Production Thereof and Use Thereof
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Process for preparing the vinyl ester of isononanoic acid starting out from 2-ethylhexanol, characterized in that (a) 2-ethylhexanol is dehydrated in the presence of a catalyst to form octene; (b) the octene obtained in step a) is converted into an isononanoic acid having one more carbon atom; and (c) the isononanoic acid obtained in step b) is converted into the corresponding vinyl ester.
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Paragraph 0075-0077
(2015/06/24)
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- Method for Producing Isononanoic Acid Esters, Starting from 2-Ethyl Hexanol
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A Process for preparing carboxylic esters of a mixture of structurally branched C9 monocarboxylic acids proceeding from 2-ethylhexanol is characterized in that (a) 2-ethylhexanol is dehydrated to an octene mixture in the presence of a catalyst; (b) the octene mixture obtained in step a) is reacted in the presence of a transition metal compound of group VIII of the periodic table of the elements with carbon monoxide and hydrogen to give a mixture of isomeric isononanals; (c) the mixture of isomeric isononanals obtained in step b) is oxidized to a mixture of structurally branched C9 monocarboxylic acids; and (d) the mixture of structurally branched C9 monocarboxylic acids obtained in step c) is reacted with alcohols to give carboxylic esters.
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Paragraph 0074-0076
(2015/06/17)
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- Method for Producing Isononanoic Acids from 2-Ethyl Hexanol
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Process for preparing isononanoic acid proceeding from 2-ethylhexanol, characterized in that (a) 2-ethylhexanol is dehydrated to octene in the presence of a catalyst; (b) the octene obtained in step a) is reacted in the presence of a transition metal compound of group VIII of the periodic table of the elements with carbon monoxide and hydrogen to give isononanal; and (c) the isononanal obtained in step b) is oxidized to isononanoic acid.
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Paragraph 0062-0063
(2015/07/15)
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- Method for the preparation and use of bis (alkoxysilylorgano)-dicarboxylates
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A method for preparing a bis(alkoxysilylorgano) dicarboxylate includes reacting a haloorganoalkoxysilane, a dimetal salt of a dicarboxyl functional compound, and a phase transfer catalyst. A quaternary iminium compound of a polyaza,polycycloalkene is useful as the phase transfer catalyst. The product may be a bis(alkoxysilylalkyl) fumarate, which is useful as a coupling agent in rubber compositions for tire applications.
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Paragraph 0075
(2013/04/10)
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- ESTER-FUNCTIONAL SILANES AND THE PREPARATION AND USE THEREOF;AND USE OF IMINIUM COMPOUNDS AS PHASE TRANSFER CATALYSTS
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A method for producing a reaction product comprising an ester-functional silane, the method comprising: i) reacting a composition comprising: a) a haloorganosilane, b) a metal salt of a carboxy-functional compound, c) a phase transfer catalyst comprising a bicyclic amidine, an iminium compound, or a mixture thereof, provided that the iminium compound is not an acyclic guanidinium compound or pyridinium compound, and d) a co-catalyst, provided that the co-catalyst is optional when the phase transfer catalyst comprises the iminium compound.
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Paragraph 0094
(2013/06/27)
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- Synthesis of renewable plasticizer alcohols by formal anti-Markovnikov hydration of terminal branched chain alkenes via a borane-free oxidation/reduction sequence
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An efficient method for the formal anti-Markovnikov hydration of 1,1-disubstituted alkenes has been developed. The utility of the process has been demonstrated by conversion of bio-derived butene oligomers into primary alcohols through initial oxidation to vicinal acetoxy-alcohols, diols, or diacetates, followed by selective dehydration/tautomerization of the diols, and hydrogenation of the intermediary aldehydes. This approach allows for the isolation of important industrial plasticizer alcohols from a renewable source. In a broader context, this pathway, which can be conducted with sustainable, conventional reagents under mild conditions, represents a unique alternative to hydroboration for a challenging subset of hindered olefins.
- Harvey, Benjamin G.,Meylemans, Heather A.,Quintana, Roxanne L.
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p. 2450 - 2456
(2013/02/23)
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- Enantioselectivity of chiral zirconocenes as catalysts in alkene hydro-, carbo- and cycloalumination reactions
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The enantioselectivity of chiral Zr catalysts L1L2ZrCl2 [L1 = L2 = 1-neomenthylindenyl (Ind*), 1; L1 = Cp, L2 = Ind* 2; L1 = Cp, L2 = 1-neomenthylindenyl-4,5,6,7-tetrahydroindenyl (Cp*) 3] in the hydro-, carbo- and cycloalumination of alkenes by organoaluminium compounds (OAC) (AlMe3, AlEt3, HAlBu2i) has been studied. It was found that OAC exhibit the most effect on the reaction chemo- and enantioselectivity. The reaction chemo- and enantioselectivity depend on the catalyst structure and reaction conditions (solvent type, catalyst concentration, temperature) as well. It is shown that the lack of asymmetric induction in the reaction of α-methylstyrene hydroalumination by HAlBu2i, catalyzed with complexes 1 or 3, is the result of the formation of Zr hydride complexes of different structures as reaction intermediates. MTPA was used as a derivatization reagent for the enantiomeric excess estimation and absolute configuration assignment of β-chiral alcohols obtained after the oxidation and hydrolysis of the reaction products. The applicability of MTPA for the assignment of the absolute configuration of the stereogenic centre in β-ethyl substituted primary alcohols and β-alkyl-1,4-butanediols is shown.
- Parfenova, Lyudmila V.,Berestova, Tatyana V.,Tyumkina, Tatyana V.,Kovyazin, Pavel V.,Khalilov, Leonard M.,Whitby, Richard J.,Dzhemilev, Usein M.
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experimental part
p. 299 - 310
(2010/06/14)
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- On study of chemoselectivity of reaction of trialkylalanes with alkenes, catalyzed with Zr π-complexes
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The influence of the organoaluminium compound nature, Zr π-ligand environment, solvent type and reagent ratio on the chemoselectivity of reactions of trialkylalanes (AlMe3, AlEt3) with alkenes, catalyzed with L2ZrCl2
- Parfenova, Lyudmila V.,Gabdrakhmanov, Vener Z.,Khalilov, Leonard M.,Dzhemilev, Usein M.
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scheme or table
p. 3725 - 3731
(2009/12/31)
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- Comparative Dimerization of 1-Butene mith a Variety of Metal Catalysts, and the Investigation of a New Catalyst for C-H Bond Activation
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Catalytic dimerization of 1-butene by a variety of catalysts is carried out, and the products are analyzed by gas chromatography and mass spectrometry. Catalysts based on cobalt and iron can produce highly linear dimers, with the cobalt-based dimers exceeding 97% linearity. Catalysts based on vanadium and aluminum prefer to make branched dimers, which are most often methyl-heptenes in the case of vanadium and almost exclusively 2-ethyl-1-butene in the case of aluminum. The vanadium catalyst also produces substantial amounts of dienes and alkanes, suggesting a competing hydrogenation/dehydrogenation pathway that appears to involve vinyl C-H bond activation. Nickel catalysts are generally less selective than those based on iron or cobalt for making linear dimers, but they can make dimers with 60% linearity. The major by-products for the nickel systems are trisubstituted internal olefins. An important side reaction that must be considered for dimerization reactions is 1-butene isomerization to 2-butene, which makes recycling the butene difficult for a linear dimerization process. Aluminum, iron, and vanadium systems promote very little isomerization, but nickel and cobalt systems tend to isomerize the undimerized substrate heavily.
- Small, Brooke L.,Schmidt, Roland
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p. 1014 - 1020
(2007/10/03)
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- Method of decomposing by-product during the production of (meth)acrylic ester
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A problem of the invention is to provide a method of decomposing a Michael addition reaction product formed as a by-product in the production step of a (meth)acrylic ester and recovering (meth)acrylic acid, a (meth)acrylic ester and an alcohol, in which the formation of an olefin as a by-product can be suppressed. The invention relates to a method of thermally decomposing a by-product at the time of production of a (meth)acrylic ester using an alcohol bearing a branched chain and having 3 or more carbon atoms, wherein the decomposition reaction is carried out in the absence of a catalyst.
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- Photochemistry of Thietane Excited to Its Second Excited Electronic Singlet State
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Thietane, excited to its S2 state, undergoes fragmentation to ethylene and thioformaldehyde by one channel and a competing reaction, unique to the S2 state, is decomposition to cyclopropane and sulfur atoms.Previous work on the S2 state of thietane has been extended to include a more detailed examination of the spectra and energy partitioning in the cyclopropane formimg reaction; and, by photolizing cis- and trans-3-ethyl-2-propylthietane, we have followed the stereochemical course of both reaction channels.The products of both reactions largely retain the stereochemistry of the reactant.Energy partitioning indicates that S(3P) is the atomic fragment when cyclopropane is produced.A mechanism which accomodates the experimental results assumes that, once excited to its 1B2 electronic state, intersystem crossing to the 3B2 state competes with C-S bond rupture that forms the 1,4-diradical intermediate which yields the ring cleavage products.The 3B2 state decomposes to cyclopropane and S(3P) by a mechanism that likely involves a singlet trimethylene diradical as an intermediate.
- Dorer, F.H.,Okazaki, M. E.,Salomon, K. E.
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p. 2671 - 2676
(2007/10/02)
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