691-37-2Relevant academic research and scientific papers
Merging Halogen-Atom Transfer (XAT) and Cobalt Catalysis to Override E2-Selectivity in the Elimination of Alkyl Halides: A Mild Route towardcontra-Thermodynamic Olefins
Zhao, Huaibo,McMillan, Alastair J.,Constantin, Timothée,Mykura, Rory C.,Juliá, Fabio,Leonori, Daniele
supporting information, p. 14806 - 14813 (2021/09/18)
We report here a mechanistically distinct tactic to carry E2-type eliminations on alkyl halides. This strategy exploits the interplay of α-aminoalkyl radical-mediated halogen-atom transfer (XAT) with desaturative cobalt catalysis. The methodology is high-yielding, tolerates many functionalities, and was used to access industrially relevant materials. In contrast to thermal E2 eliminations where unsymmetrical substrates give regioisomeric mixtures, this approach enables, by fine-tuning of the electronic and steric properties of the cobalt catalyst, to obtain high olefin positional selectivity. This unprecedented mechanistic feature has allowed access tocontra-thermodynamic olefins, elusive by E2 eliminations.
METHOD OF PRODUCING TERMINAL DOUBLE BOND-CONTAINING COMPOUND
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Paragraph 0044-0048, (2020/10/09)
SOLUTION: A method of producing a terminal double bond-containing compound includes: reacting a compound represented by the following general formula (I) under a pressure of 0 MPa-G or lower in the presence of a metal oxide catalyst to produce a terminal double bond-containing compound represented by the following general formula (II). In formula (I) and formula (II), R1 and R2 represent hydrocarbon groups, and R1 and R2 may bond each other to form a ring together with carbon atoms by which R1 and R2 bond. EFFECT: According to the present invention, a terminal double bond-containing compound can be safely and easily produced with high selectivity. SELECTED DRAWING: None COPYRIGHT: (C)2020,JPOandINPIT
CATALYSTS AND METHODS FOR DIMERIZING PROPYLENE
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Paragraph 0052-0057, (2020/02/06)
Catalysts for producing a branched aliphatic alkene are described. The catalyst can include a catalytic alkali metal or alkali metal composite on a mixed metal oxide support that includes a Column 1 metal and at least one of a Column 3 metal, a Column 4 metal or a lanthanide. The catalyst can have less than 50 wt.% of a metal carbonate. Methods of producing branched aliphatic alkenes by contacting the catalyst of the present invention with an aliphatic alpha olefin are also described.
Pyridylamido hafnium complexes with a silylene bridge: Synthesis and olefin polymerization
Canich, Jo Ann M.,Hagadorn, John R.,Kulyabin, Pavel S.,Uborsky, Dmitry V.,Voskoboynikov, Alexander Z.
supporting information, p. 6693 - 6702 (2020/06/08)
The synthesis and characterisation of six novel Cs-symmetric pyridylamido hafnium complexes with a silylene bridge of the type [ArPy(R2Si)NAr′]HfAlk2 are reported. Four complexes have been structurally characterised using single crystal X-ray diffraction. Appreciable differences between the solid state structures of these complexes and the pyridylamido hafnium complexes with a CRR′ bridge were noted. Reactions with B(C6F5)3, [Ph3C][B(C6F5)4] and [HMe2NPh][B(C6F5)4] yielded active catalysts for the homopolymerisations of propene and 1-hexene and ethene/1-octene copolymerization. In spite of the Cs-symmetry of the precatalysts, isotactically enriched polypropylene and poly(1-hexene) were obtained. The fact that the mechanism of the catalyst activation includes the insertion of alkene into the Hf-CAr bond was demonstrated. It was found that the structures of Ar and the R2Si bridge influence the activity, molecular weight capability and 1-octene affinity of the catalysts.
Synthesis, structure and reactivity of some chiral benzylthio alcohols, 1,3-oxathiolanes and their S-oxides
Aitken, R. Alan,Lightfoot, Philip,Thomas, Andrew W.
, p. 369 - 387 (2020/05/25)
A series of amino acid-derived chiral benzylthio alcohols have been prepared and characterized. A chiral mercapto alcohol derived from S-leucine has been used to form three chiral 2,4-disubstituted 1,3-oxathiolanes. One of these has been oxidized to the S-oxide and another to the S,S-dioxide. The cis and trans isomers have been characterized by 1H NMR in each case and it appears that thermal epimerisation at C-2 is possible at the sulfoxide oxidation state. The X-ray structure of major trans diastereomer of 2-phenyl-4-isobutyl-1,3-oxathiolane S,S-dioxide shows an envelope conformation with oxygen at the flap and an internal angle at sulfur of just 93.8°. This compound fragments upon flash vacuum pyrolysis at 700°C to give SO2, benzaldehyde and 4-methylpent-1-ene.
METHOD FOR PRODUCING 4-METHYL-1-PENTENE
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Paragraph 0021; 0022, (2018/05/05)
PROBLEM TO BE SOLVED: To provide a method for producing 4-methyl-1-pentene that can inhibit the by-production of olefins other than 4-methyl-1-pentene and is relatively safe. SOLUTION: A method for producing 4-methyl-1-pentene includes the step of dehydrating 4-methyl-1-pentanol in the presence of a solid acid catalyst. SELECTED DRAWING: None COPYRIGHT: (C)2018,JPOandINPIT
Dispersion of nanosized ceria-terbia solid solutions over silica surface: Evaluation of structural characteristics and catalytic activity
Miah, Abu Taleb,Saikia, Pranjal
, p. 96 - 104 (2018/04/05)
In this work, we investigated the dispersion effects of nanosized ceria-terbia solid solutions over silica surface in terms of structural characteristics and catalytic activity. The dispersion process was carried out via a soft chemical route using colloidal silica precursor and nitrate precursors of cerium and terbium. The structural features were elucidated by means of analytical techniques namely TGA, BET surface area, XRD, Raman Spectroscopy, UV-vis DRS, TEM, XPS, and TPR-TPO. The catalyst samples were subjected to thermal treatments at different temperatures ranging from 773 to 1073 K to understand the influence of silica support on dispersion, textural properties, and thermal stability. Catalytic activity was evaluated for selective dehydration of 4-methylpentan-2-ol to 4-methylpent-1-ene in the vapor phase at atmospheric pressure. The silica supported ceria-terbia catalyst exhibited better dehydration activity as well as selectivity in comparison to the unsupported catalyst. The catalytic properties were found to be dependent on structural features of the prepared catalyst samples.
Palladium-Catalyzed Electrochemical Allylic Alkylation between Alkyl and Allylic Halides in Aqueous Solution
Lai, Yin-Long,Huang, Jing-Mei
supporting information, p. 2022 - 2025 (2017/04/28)
A new route for the direct cross-coupling of alkyl and allylic halides using electrochemical technique has been developed in aqueous media under air. Catalyzed by Pd(OAc)2, the Zn-mediated allylic alkylations proceed smoothly between a full range of alkyl halides (primary, secondary, and tertiary) and substituted allylic halides. Protection-deprotection of acidic hydrogen in the substrates is avoided.
Low Temperature Oligomerization of Ethylene over Ni/Al-KIT-6 Catalysts
Hwang, Ahron,Kim, Sungtak,Kwak, Geunjae,Kim, Seok Ki,Park, Hae-Gu,Kang, Seok Chang,Jun, Ki-Won,Kim, Yong Tae
, p. 1303 - 1314 (2017/05/19)
Abstract: In this paper, we have studied the oligomerization of ethylene with a liquid heptane solvent over bifunctional Ni catalysts in a continuous flow reactor. We have prepared an Al-containing KIT-6 silica that was used as a support after calcination in the temperature range of 300–900 °C. The Ni/Al-KIT-6 catalysts had uniform mesopores with diameters in the range of 5.4–6.3 nm, excepting Ni/Al-KIT-6 (900). The calcination temperature of Al-KIT-6 support changed the surface acidity as well as the interaction of Ni2+ and acid sites for the Ni catalysts, as determined by temperature-programmed desorption of ammonia, temperature-programmed reduction, infrared spectroscopy after the adsorption of pyridine, solid-state 27Al magic-angle spinning nuclear magnetic resonance spectroscopy, and X-ray adsorption spectroscopy. Among the tested catalysts, the Ni/Al-KIT-6 (300) showed the highest ethylene conversion because of the increased intimate contact between Ni2+ and acid sites. The strong interaction of Ni2+ species and the support is not effective in increasing active sites for ethylene conversion. The Ni/Al-KIT-6 catalysts produced internal linear C4 and C6 olefins with high selectivity. The Ni/Al-KIT-6 (300) had 2.2–6.1 times lower selectivities toward 2-ethyl-1-butene than other catalysts at similar ethylene conversions. The reaction product mixture showed that the Ni/Al-KIT-6 catalysts shifted the product distribution towards acid-catalyzed oligomerization/cracking/realkylation products (i.e. C3, C7, C7, and C8+ olefins) as the concentration of Br?nsted acid sites increased. Among the tested catalysts, the Ni/Al-KIT-6 (300) showed the highest yield of C4 and C6 olefins (78.3%). Graphical Abstract: [Figure not available: see fulltext.].
Dimerization method for high activity and selectivity propylene
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Paragraph 0114; 0115; 0116; 0118-0121; 0124-0139; 0142-0153, (2017/06/02)
The invention provides a dimerization method for high activity and selectivity propylene. The method includes the following steps that methylaluminoxane (MAO) or modified methylaluminoxane (MMAO) is used as a catalyst promoter, and the propylene is subjected to a dimerization reaction under the catalytic action of an ethylidene bridged substituted diindene titanium group metal complex catalyst; and the ethylidene bridged substituted diindene titanium group metal complex catalyst is an internal compensation (meso-) ethylidene bridged substituted diindene titanium group metal complex catalyst or a racemization (rac-) ethylidene bridged substituted diindene titanium group metal complex catalyst. Compared with the prior art, the dimerization method provided by the invention is high in catalytic activity and high in dimerization selectivity, the rate can reach 99%, numerous follow-up operation steps in separation of products with the high degree of polymerization are omitted, the industrialization cost is reduced, and the industrial production needs can be met.
