- Chromium-Catalyzed Production of Diols From Olefins
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Processes for converting an olefin reactant into a diol compound are disclosed, and these processes include the steps of contacting the olefin reactant and a supported chromium catalyst comprising chromium in a hexavalent oxidation state to reduce at least a portion of the supported chromium catalyst to form a reduced chromium catalyst, and hydrolyzing the reduced chromium catalyst to form a reaction product comprising the diol compound. While being contacted, the olefin reactant and the supported chromium catalyst can be irradiated with a light beam at a wavelength in the UV-visible spectrum. Optionally, these processes can further comprise a step of calcining at least a portion of the reduced chromium catalyst to regenerate the supported chromium catalyst.
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Paragraph 0111
(2021/03/19)
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- Environment-friendly method for synthesizing propenyl ketone compound
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The invention discloses an environment-friendly method for synthesizing a propenyl ketone compound. The method comprises the following steps: subjecting an aldehyde compound and allyl bromide to a Barbier reaction in the presence of metal powder, so as to obtain an allyl alcohol compound; and subjecting the allyl alcohol compound to a structural isomerization reaction in the presence of a catalyst, thereby obtaining the propenyl ketone compound. The method disclosed by the invention has the advantages of short synthesis route, mild reaction conditions, simplicity in operation, readily available raw materials, and the like and has relatively high academic research value and market economy significance.
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Paragraph 0019; 0021
(2019/01/04)
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- Expedient Synthesis of 1,5-Diketones by Rhodium-Catalyzed Hydroacylation Enabled by C-C Bond Cleavage
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A rhodium-catalyzed intermolecular hydroacylation reaction of vinyl cyclobutanols with non-chelating aldehydes has been developed. This reaction offers a new and atom-economical approach for the selective preparation of 1,5-diketones in high yields. Experimental data suggest a sequential ring-opening, transfer hydrogenation, and hydroacylation mechanism. We propose that aldehyde decarbonylation is avoided by the formation of a novel rhodium enolate species that also accounts for the compatibility of a broad range of aldehydes and its anti-Markovnikov selectivity.
- Guo, Rui,Zhang, Guozhu
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supporting information
p. 12891 - 12894
(2017/09/26)
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- 4-hydroxy-3-hexanone catalytic dehydration method
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The invention relates to a 4-hydroxyl-3-hexanone catalytic dehydration method and mainly aims to solve the problems of a catalyst in the prior art, such as low activity, high reaction temperature and low space velocity. According to the technical scheme, 4-hydroxyl-3-hexanone serving as a raw material comes into contact with a catalyst to generate 4-hexylene-3-hexanone under the conditions that the reaction temperature ranges from 200 DEG C to 400 DEG C and the liquid mass space velocity relative to the 4-hydroxyl-3-hexanone is equal to 0.5-15h, wherein the used catalyst has the crystal grain diameter being at most 5mm, and has ZSM-5 zeolite with mesopores and micropores, and the ratio of the volume of the mesopores to the volume of the micropores in the ZSM-5 zeolite is equal to 1.5-10. The problems in the prior art can be well solved by adoption of the technical scheme. The 4-hydroxyl-3-hexanone catalytic dehydration method can be used for industrial production of 4-hexylene-3-hexanone prepared by using the 4-hydroxyl-3-hexanone.
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Paragraph 0020-0024; 0052
(2017/01/09)
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- POSS-derived mesoporous ionic copolymer-polyoxometalate catalysts with a surfactant function for epoxidation reactions
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A series of novel polyoxometalate (POM)-based stable polymeric hybrids were successfully synthesized using polyhedral oligomeric vinylsilsesquioxanes (POSS) and ionic liquids (IL) bearing hydrophobic alkyl chains as the building blocks, followed by ion exchange with Keggin-type phosphotungstic acid (PW). The obtained hybrids POSS-ILx-PW were demonstrated to be mesostructured and amphiphilic materials with good thermal stability. Catalytic tests for the H2O2-based epoxidation of cyclooctene have shown that these newly designed catalysts exhibit extraordinary catalytic activities, catalytic rates, and quite stable reusability. The unique amphiphilic property and the mesoporous structure are revealed to be responsible for the catalysts' excellent performance in epoxidation reactions with H2O2.
- Zhao, Jiwei,Leng, Yan,Jiang, Pingping,Wang, Jun,Zhang, Chenjun
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p. 1022 - 1028
(2016/02/19)
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- High turnover numbers for the catalytic selective epoxidation of alkenes with 1 atm of molecular oxygen
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The diiron-substituted silicotungstate γ-SiW10{Fe3+(OH2}2O 386- (schematically shown) is an effective catalyst for the oxygenation of alkenes in homogeneous reaction media with 1 atm of molecular oxygen. For example, a selectivity for cyclooctene oxide of 98% and a turnover number of 10000 were achieved in the epoxidation of cyclooctene. The catalyst is stable under the reaction conditions, and its ability to use molecular oxygen raises the prospect of using it in industrial epoxidation processes.
- Nishiyama, Yoshiyuki,Nakagawa, Yoshinao,Mizuno, Noritaka
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p. 3639 - 3641
(2007/10/03)
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- β-Carbonyl substituted glutathione conjugates as inhibitors of O. volvulus GST2
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A series of β-carbonyl substituted glutathione conjugates were prepared and evaluated as inhibitors of OvGST2. Their specificity for the parasite derived protein was assessed through comparison with their inhibition of human πGST. Inhibition of OvGST2 has been demonstrated at low micromolar concentrations for these conjugates and selectivity for OvGST2 over human π-GST of greater than 10-fold has been achieved. (C) 2000 Elsevier Science Ltd. All rights reserved.
- Brophy, Peter M.,Campbell, Alison M.,Van Eldik, Annamaria J.,Teesdale-Spittle, Paul H.,Liebau, Eva,Wang, Meng F.
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p. 979 - 981
(2007/10/03)
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- Lewis Acid-Promoted Coupling Reactions of Acid Chlorides with Organoaluminum and Organozinc Reagents
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An efficient synthesis of α,α-unsaturated ketones by the reaction of acid chlorides with trialkyl-aluminum (1/3 mole equiv) in the presence of AlCl3 (1 mol equiv) is described. Dialkylzincs were also useful and are easier to prepare than trialkylaluminum. Reaction of RCOCl with R′AlCl3 or R′2AlCl gave R′COR, without AlCl3, in high yield.
- Arisawa, Mitsuhiro,Torisawa, Yasuhiro,Kawahara, Michiaki,Yamanaka, Masamichi,Nishida, Atsushi,Nakagawa, Masako
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p. 4327 - 4329
(2007/10/03)
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- Practical synthesis of (E)-pent-3-en-2-one and its conversion to (E)-2-triethylsilyloxypenta-1,3-diene
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An improved procedure for the preparation of (E)-pent-3-en-2-one in high yields utilizing a Friedel-Crafts type alkylation of crotonyl chloride with trimethylaluminum is reported. Conversion of this enone into the corresponding enol silyl ether is also described.
- Arisawa,Torisawa,Nakagawa
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p. 1371 - 1372
(2007/10/02)
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- Stereochemistry of the Michael Addition of N,N-Disubstituted Amide and Thioamide Enolates to α,β-Unsaturated Ketones
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A systematic study of the regio- and diastereoselectivity of the kinetic Michael addition of amide and thioamide enolates to a series of α,β-unsaturated ketones has been carried out.Factors that influence the diastereo- and regiochemical outcome of the reaction include the substitution pattern of the enone and enolate, the enolate counterion, and the solvent.Numerous examples of high selectivity have been discovered.In a number of examples, either the syn or the anti addition products can be obtained by varying the nature of the solvent, donor atom, and/or counterion.These results have correlated in terms of a coherent transition-state model.
- Oare, David A.,Henderson, Mark A.,Sanner, Mark A.,Heathcock, Clayton H.
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p. 132 - 157
(2007/10/02)
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- Condensation of Propiolactones with Phosphorus Ylides: a Convenient Synthesis of α,β-Ethylenic Ketones
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δ-Hydroxy-β-ketophosphoranes have been obtained by condensation of propiolactones with ylides and afforded α,β-unsaturated ketones on heating.
- Le Roux, Juliette,Le Corre, Maurice
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p. 1464 - 1465
(2007/10/02)
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- Chromium(II) Reagents; 1. Reduction of α-Acetylenic Ketones to trans-Enones
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The preparation and chromium(II)-induced reduction of twelve α-acetylenic ketones are reported.In general only trans-olefinic products were observed; the yields ranged from 40-84percent.A particular advantage of this protocol is its selectivity, thereby permitting use with a wide variety of functionalities.
- Smith, Amos B.,Levenberg, Patricia A.,Suits, Joan Z.
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p. 184 - 189
(2007/10/02)
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- Synthesis of β,γ- and α,β-Unsaturated Ketones Using Allyltitanium Reagents
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Carboxylic acid imidazolides (N-acylimidazoles) (4, 7a-c, 12) react with allyltitanium tris(amides) (3b, c, 10) to form β,γ-unsaturated ketones (5, 8a-c, 11a-d, 13) without carbinol formation or isomerization of the olefinic double bond.Controlled isomerization to α,β-isomers having E-configuration is possible under mild conditions using Al2O3.
- Reetz, Manfred T.,Wenderoth, Bernd,Urz, Ralf
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p. 348 - 353
(2007/10/02)
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- Complexations of 1,4-Dienes to Rhodium(I) Pentane-2,4-dionates; Thermal Rearrangements of the Complexes
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As models for natural products containing a 'skipped' diene fragment (-CH=CHCH2CH=CH-), a series of hepta-2,5-dienes, hepta-2,5-dien-4-ols, and hepta-2,5-dien-4-ol acetates have been prepared.Some of these dienes react with either bis(ethylene)(pentane-2,4-dionato)rhodium(I) or bis(ethylene)(1,1,1,5,5,5-hexafluoropentane-2,4-dionato)rhodium(I) to afford 1:1 complexes, e.g. (1,1,1,5,5,5-hexafluoropentane-2,4-dionato)rhodium(I).Other dienes, e.g. (Z,Z)-hepta-2,5-diene, form 2:1 complexes in which for each molecule of diene, one double bond is co-ordinated to rhodium, whereas the other is not.The (Z,Z)-dienes do not form 1:1 complexes because there would be a severe steric interaction between the terminal substituents of each double bond in such complexes.For the complexes of the dienols and certain allylic alcohols (e.g. prop-2-en-1-ol), evidence was obtained for the presence of a stabilizing intramolecular hydrogen bond between each OH and its nearest CO of the pentane-2,4-dionate.When heated in benzene with 5 mol percent of bis(ethylene)-(pentane-2,4-dionato)rhodium(I) each dienol rearranged to give an enone as the main product .Their acetates rearranged to isomeric conjugated dienes .The hepta-2,5-dienes were recovered unchanged.The mechanism of the rearrangements observed are explained in terms of intermediate (?-allyl)rhodium complexes.
- Aneja, Rajindra,Golding, Bernard T.,Pierpoint, Colin
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p. 219 - 224
(2007/10/02)
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- Reaction of Aromatic Sulfonyl Azides with Dienes
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THe addition of aromatic sulfonyl azides to simple acyclic and cyclic dienes in a 1:2 molar ratio was investigated.In no case was the triazoline cycloaddition product isolated from the thermal cycloaddition.With the nonconjugated dienes 1,5-hexadiene and 1,7-octadiene, hydrogen migration occurred with nitrogen loss, affording sulfonimide products.No evidence for olefinic participation or alkyl group migration was obtained.Hydrolysis of the sulfonimides gave the corresponding unsaturated ketones 5-hexen-2-one and 7-octen-2-one, respectively.Conjugated dienes reacted with aromatic sulfonyl azides to give enamines rather than sulfonimides.The reaction of p-nitrobenzenesulfonyl azide with 1,3-cyclohexadiene followed by hydrolysis afforded only 2-cyclohexen-1-one resulting from hydrogen migration.Addition to either cis,trans- or trans,trans-2,4-hexadiene gave, after hydrolysis, trans-4-hexen-3-one and trans-2-methyl-2-pentenal arising from competitive hydrogen and vinyl group migration, respectively.
- Abramovitch, Rudolph A.,Ortiz, Margarita,McManus, Samuel P.
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p. 330 - 335
(2007/10/02)
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- IMPROVED SYNTHESIS OF β,γ-UNSATURATED KETONES BY THE REACTION OF ALLYLIC ZINC BROMIDES WITH NITRILES.
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The reaction of allylic bromides with nitriles in the presence of Zn-Ag couple leads, after hydrolysis, to β,γ-unsaturated ketones in high yield.
- Rousseau, G.,Conia, J. M.
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p. 649 - 652
(2007/10/02)
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- Process for preparing ketones using zinc acetate condensation catalysts, products produced thereby and organoleptic uses of same
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Described is a process for the production of alpha, beta unsaturated ketones by reaction of an aldehyde with a ketone in the presence of a catalyst consisting essentially of either zinc acetate or zinc acetate dihydrate. The ketones obtained are suitable and some cases as solvents and in some cases as intermediates for the production of valuable odorants, dyes, plastics and especially nature-identical substances and are also useful as odorants per se.
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