- A recoverable Pd nanocatalyst for selective semi-hydrogenation of alkynes: Hydrogenation of benzyl-propargylamines as a challenging model
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We describe a recyclable heterogeneous palladium nanocatalyst for the selective hydrogenation of alkynes to alkenes. The catalyst was prepared through the decomposition of the organometallic precursor Pd2(dba)3 over a magnetic support, obtaining well-dispersed Pd nanoparticles that formed exclusively on the support surface, with average diameter of 3.5 ± 0.8 nm. The catalytic activity was investigated in the hydrogenation reactions of alkenes and alkynes, and the chemo- and stereoselectivity were evaluated in the hydrogenation of benzyl-propargylamines. The catalyst is highly selective in performing semi-hydrogenation reactions under mild conditions and short reaction times, with good overall yields. Furthermore, it can be easily recovered and recycled, with no leaching of palladium detected, and activities and selectivity retained over multiple reaction cycles. This journal is
- Uberman, Paula M.,Costa, Natalia J. S.,Philippot, Karine,C. Carmona, Rafaela,Dos Santos, Alcindo A.,Rossi, Liane M.
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- Vapor-phase dehydration of 1,4-butanediol to 1,3-butadiene over Y2Zr2O7 catalyst
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Vapor-phase catalytic dehydration of 1,4-butanediol (1,4-BDO) was investigated over Y2O3-ZrO2 catalysts. In the dehydration, 1,3-butadiene (BD) together with 3-buten-1-ol (3B1OL), tetrahydrofuran, and propylene was produced depending on the reaction conditions. In the dehydration over Y2O3-ZrO2 catalysts with different Y contents at 325°C, Y2Zr2O7 with an equimolar ratio of Y/Zr showed high selectivity to 3B1OL, an intermediate to BD. In the dehydration at 360°C, a BD yield higher than 90% was achieved over the Y2Zr2O7 calcined at 700°C throughout 10 h. In the dehydration of 3B1OL over Y2Zr2O7, however, the catalytic activity affected by the calcination temperature is roughly proportional to the specific surface area of the sample. The highest activity of Y2Zr2O7 calcined at 700 °C for the BD formation from 1,4-BDO is explained by the trade-off relation in the activities for the first-step dehydration of 1,4-BDO to 3B1OL and for the second-step dehydration of 3B1OL to BD. The higher reactivity of 3B1OL than saturated alcohols such as 1-butanol and 2-butanol suggests that the C=C double bond of 3B1OL induces an attractive interaction to anchor the catalyst surface and promotes the dehydration. A probable mechanism for the one-step dehydration of 1,4-BDO to BD was discussed.
- Matsuda, Asami,Matsumura, Yoshitaka,Sato, Satoshi,Yamada, Yasuhiro
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- Selective production of 1,3-butadiene from 1,3-butanediol over Y2Zr2O7 catalyst
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The vapor-phase dehydration of 1,3-butanediol (1,3-BDO) to produce 1,3-butadiene (BD) was evaluated over yttrium zirconate, which was prepared through a hydrothermal aging process. 1,3-BDO was initially dehydrated to three unsaturated alcohols, namely 3-buten-2-ol, 3-buten-1-ol, and 2-buten-1-ol, followed by the further dehydration to BD. The catalytic activity of yttrium zirconate was greatly dependent on the calcination temperature. Also, the reaction temperature was one of the important factors to produce BD efficiently. The selectivity to BD was increased with increasing reaction temperature up to 375°C, while coke formation resulted in catalyst deactivation together with by-product formation at higher temperatures. Yttrium zirconate catalyst calcined at 900°C showed a high BD yield of 95% at 375°C and 10 hr on stream.
- Matsuda, Asami,Matsumura, Yoshitaka,Sato, Satoshi,Yamada, Yasuhiro
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p. 1651 - 1658
(2021/07/21)
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- Preparation method of 3-butene-1-ol
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The invention relates to a preparation method of 3-butene-1-ol. Ethyl acetate is used as a solvent, allyl bromide, zinc powder, formaldehyde and ammonium chloride are used as raw materials, copper salt is used as a catalyst, and a reaction product is 3-butene-1-ol. The reaction yield is greater than 87%, and the purity is greater than 99%. In order to overcome the defects in the prior art, the catalyst is added, so that the reaction time is greatly shortened; a distillation method is used for replacing multiple times of extraction treatment of the reaction water phase, the operation is easierand more convenient, and the cost is greatly reduced; and an environment-friendly organic matter is used as the solvent, and the green and environment-friendly production concept is met.
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Paragraph 0009-0013
(2020/10/05)
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- Selective oxidation of crotyl alcohol by Au: X Pd bimetallic pseudo-single-atom catalysts
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AuPd bimetallic single-atom catalysts are being extensively studied as selective catalysts for hydrogenation and oxidation reactions due to their high selectivity. Previous work in our group has shown that alloy and core-shell AuPd nanoparticle catalysts can selectively oxidize crotyl alcohol to crotonaldehyde at room temperature in base-free conditions. In this work, we discuss the synthesis, extensive characterization, and activity for crotyl alcohol oxidation across a series of AuxPd catalysts (x = 4, 3, 2, and 1) made by both co-reduction and sequential reduction strategies, in order to examine whether single-atom systems can lead to improved activity and/or selectivity for this reaction. X-ray absorption spectroscopy data shows that both co-and sequentially-reduced Au4Pd catalysts have very small Pd-Pd coordination numbers, with values of 1.2 ± 0.3 and 1.6 ± 0.3, respectively, which indicates that they are closest to single-atom systems. The co-Au4Pd catalyst, with the lowest Pd-Pd CN, also exhibits the highest selectivity for the selective oxidation of crotyl alcohol to crotonaldehyde. We were further able to enhance the selectivity of the AuPd nanoparticle catalysts by incorporating vinyl acetate as a hydride scavenger. We show in this paper that dispersing Pd in a Au matrix can lead to very selective catalysts while also lowering the amount of Pd needed in the system.
- Chivers, Brandon A.,Scott, Robert W. J.
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p. 7706 - 7718
(2020/11/27)
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- Dialkyl Ether Formation at High-Valent Nickel
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In this article, we investigated the I2-promoted cyclic dialkyl ether formation from 6-membered oxanickelacycles originally reported by Hillhouse. A detailed mechanistic investigation based on spectroscopic and crystallographic analysis revealed that a putative reductive elimination to forge C(sp3)-OC(sp3) using I2 might not be operative. We isolated a paramagnetic bimetallic NiIII intermediate featuring a unique Ni2(OR)2 (OR = alkoxide) diamond-like core complemented by a μ-iodo bridge between the two Ni centers, which remains stable at low temperatures, thus permitting its characterization by NMR, EPR, X-ray, and HRMS. At higher temperatures (>-10 °C), such bimetallic intermediate thermally decomposes to afford large amounts of elimination products together with iodoalkanols. Observation of the latter suggests that a C(sp3)-I bond reductive elimination occurs preferentially to any other challenging C-O bond reductive elimination. Formation of cyclized THF rings is then believed to occur through cyclization of an alcohol/alkoxide to the recently forged C(sp3)-I bond. The results of this article indicate that the use of F+ oxidants permits the challenging C(sp3)-OC(sp3) bond formation at a high-valent nickel center to proceed in good yields while minimizing deleterious elimination reactions. Preliminary investigations suggest the involvement of a high-valent bimetallic NiIII intermediate which rapidly extrudes the C-O bond product at remarkably low temperatures. The new set of conditions permitted the elusive synthesis of diethyl ether through reductive elimination, a remarkable feature currently beyond the scope of Ni.
- Le Vaillant, Franck,Reijerse, Edward J.,Leutzsch, Markus,Cornella, Josep
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supporting information
p. 19540 - 19550
(2020/12/01)
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- Synthesis of α,β- and β-Unsaturated Acids and Hydroxy Acids by Tandem Oxidation, Epoxidation, and Hydrolysis/Hydrogenation of Bioethanol Derivatives
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We report a reaction platform for the synthesis of three different high-value specialty chemical building blocks starting from bio-ethanol, which might have an important impact in the implementation of biorefineries. First, oxidative dehydrogenation of ethanol to acetaldehyde generates an aldehyde-containing stream active for the production of C4 aldehydes via base-catalyzed aldol-condensation. Then, the resulting C4 adduct is selectively converted into crotonic acid via catalytic aerobic oxidation (62 % yield). Using a sequential epoxidation and hydrogenation of crotonic acid leads to 29 % yield of β-hydroxy acid (3-hydroxybutanoic acid). By controlling the pH of the reaction media, it is possible to hydrolyze the oxirane moiety leading to 21 % yield of α,β-dihydroxy acid (2,3-dihydroxybutanoic acid). Crotonic acid, 3-hydroxybutanoic acid, and 2,3-dihydroxybutanoic acid are archetypal specialty chemicals used in the synthesis of polyvinyl-co-unsaturated acids resins, pharmaceutics, and bio-degradable/ -compatible polymers, respectively.
- Faria, Jimmy,Komarneni, Mallik R.,Li, Gengnan,Pham, Tu,Resasco, Daniel E.,Ruiz, Maria P.,Santhanaraj, Daniel
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supporting information
p. 7456 - 7460
(2020/03/23)
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- Palladium-Catalyzed Selective Reduction of Carbonyl Compounds
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Two new examples of structurally characterized β-diketiminate analogues i.e., conjugated bis-guanidinate (CBG) supported palladium(II) complexes, [LPdX]2; [L= {(ArHN)(ArN)–C=N–C=(NAr)(NHAr)}; Ar = 2,6-Et2-C6H3], X = Cl (1), Br (2) have been reported. The synthesis of complexes 1–2 was achieved by two methods. Method A involves deprotonation of LH by nBuLi followed by the treatment of LLi (insitu formed) with PdCl2 in THF, which afforded compound 1 in good yield (75 %). In Method B, the reaction between free LH and PdX2 (X = Cl or Br) in THF allowed the formation of complexes 1 (Yield 73 %) and 2 (Yield 52 %), respectively. Moreover, these complexes were characterized thoroughly by several spectroscopic techniques (1H, 13C NMR, UV/Vis, FT-IR, and HRMS), including single-crystal X-ray structural and elemental analyses. In addition, we tested the catalytic activity of these complexes 1–2 for the hydroboration of carbonyl compounds with pinacolborane (HBpin). We observed that compound 1 exhibits superior catalytic activity when compared to 2. Compound 1 efficiently catalyzes various aldehydes and ketones under solvent-free conditions. Furthermore, both inter- and intramolecular chemoselectivity hydroboration of aldehydes over other functionalities have been established.
- Sarkar, Nabin,Mahato, Mamata,Nembenna, Sharanappa
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p. 2295 - 2301
(2020/05/18)
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- Catalytic Dehydration of 1,4-Butanediol over Mg?Yb Binary Oxides and the Mechanism Study
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In this study, Mg?Yb binary oxides were synthesized using different MgO concentrations and investigated for the catalytic dehydration of 1,4-butanediol (BDO) into 3-buten-1-ol (BTO). The physicochemical properties of the catalysts were characterized by N
- Hu, Zhun,Mi, Rongli,Yang, Bolun,Yi, Chunhai
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- Vapor-phase catalytic dehydration of butanediols to unsaturated alcohols over yttria-stabilized zirconia catalysts
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Vapor-phase catalytic dehydration of butanediols (BDOs) such as 1,3-, 1,4-, and 2,3-butanediol was investigated over yttria-stabilized tetragonal zirconia (YSZ) catalysts as well as monoclinic zirconia (MZ). BDOs were converted to unsaturated alcohols with some by-products over YSZ and MZ. YSZ is superior to MZ for these reactions in a view point of selective formation of unsaturated alcohols. Calcination temperature of YSZ significantly affected the products selectivity as well as the conversion of BDOs: high selectivity to unsaturated alcohols was obtained over the YSZ calcined at high temperatures over 800 °C. In the conversion of 1,4-butanediol at 325 °C, the highest 3-buten-1-ol selectivity of 75.3% was obtained over the YSZ calcined at 1050 °C, whereas 2,3-butanediol was less reactive than the other BDOs. In the dehydration of 1,3-butanediol at 325 °C, in particular, it was found that a YSZ catalyst with a Y2O3 content of 3.2 wt.% exhibited an excellent stable catalytic activity: the highest selectivity to unsaturated alcohols such as 2-buten-1-ol and 3-buten-2-ol over 98% was obtained at a conversion of 66%. Structures of active sites for the dehydration of 1,3-butanediol were discussed using a crystal model of tetragonal ZrO2 and a probable model structure of active site was proposed. The well-crystalized YSZ inevitably has oxygen defect sites on the most stable surface of tetragonal ZrO2 (101). The defect site, which exposes three cations such as Zr4+ and Y3+, is surrounded by six O2? anions. The selective dehydration of 1,3-butanediol to produce 3-buten-2-ol over the YSZ could be explained by tridentate interactions followed by sequential dehydration: the position-2 hydrogen is firstly abstracted by a basic O2? anion and then the position-1 hydroxyl group is subsequently or simultaneously abstracted by an acidic Y3+ cation. Another OH group at position 3 plays an important role of anchoring 1,3-butanediol to the catalyst surface. Thus, the selective dehydration of 1,3-butanediol could proceed via the speculative base-acid-concerted mechanism.
- Ohtsuka, Shota,Nemoto, Takuma,Yotsumoto, Rikako,Yamada, Yasuhiro,Sato, Fumiya,Takahashi, Ryoji,Sato, Satoshi
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- Importance of the Nature of the Active Acid/Base Pairs of Hydroxyapatite Involved in the Catalytic Transformation of Ethanol to n-Butanol Revealed by Operando DRIFTS
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Operando DRIFTS is used to identify the nature and the role of the surface sites of hydroxyapatites (HAps) involved in the catalytic transformation of ethanol to n-butanol. The surface processes occurring upon a first reaction step followed by a step under He flow greatly influence the reactivity of HAps in a subsequent second reaction step. Ethanol is found to be mostly activated by the basic OH? groups of HAps, as indicated by the concomitant recovery of ethanol conversion and OH? groups under He flow. The drastic changes in selectivity observed during the second reaction step reveal the key role of acidic sites cooperatively acting with basic sites for basic reaction steps. Once the POH groups are poisoned by extensive formation of polymeric carbon species and the Ca2+ sites are available, the production of acetaldehyde is drastically promoted at the expense of that of n-butanol. It is concluded that i) acetaldehyde acts as an intermediate in the formation of n-butanol, and ii) various active sites are involved in the key basic reaction steps such as Ca2+?OH? and POH?OH? acid-base pairs in the dehydrogenation of ethanol to acetaldehyde and the aldol condensation for n-butanol formation, respectively.
- Osman, Manel Ben,Krafft, Jean-Marc,Thomas, Cyril,Yoshioka, Tetsuya,Kubo, Jun,Costentin, Guylène
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p. 1765 - 1778
(2019/02/26)
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- In situ DRIFTS for the mechanistic studies of 1,4-butanediol dehydration over Yb/Zr catalysts
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To study the effect of acid-base properties of catalysts on 1,4-butanediol (BDO) dehydration to 3-buten-1-ol (BTO), Yb/Zr catalysts with different Yb content were synthesized by a wet impregnation method. The texture property, crystalline form and surface
- Mi, Rongli,Hu, Zhun,Yang, Bolun
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p. 138 - 151
(2019/01/04)
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- SYNTHESIS OF PHEROMONES AND RELATED MATERIALS VIA OLEFIN METATHESIS
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Methods for preparation of olefins, including 8- and 11-unsaturated monoenes and polyenes, via transition metathesis-based synthetic routes are described. Metathesis reactions in the methods are catalyzed by transition metal catalysts including tungsten-, molybdenum-, and ruthenium-based catalysts. The olefins include insect pheromones useful in a number of agricultural applications.
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Paragraph 0257
(2018/09/12)
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- Visible light-driven photocatalytic generation of sulfonamidyl radicals for alkene hydroamination of unsaturated sulfonamides
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A visible light-driven photocatalytic generation of sulfonamidyl radicals, and application to intramolecular alkene hydroamination, has been accomplished, providing a mild and efficient approach to various functionalized isoxazolidines. The success of this protocol is based on the strategy of oxidative deprotonation electron transfer by merging the base and the photocatalyst under visible light irradiation, obviating installation of a photolabile handle or stoichiometric external oxidants.
- Chen, Jun,Guo, Hong-Mei,Zhao, Quan-Qing,Chen, Jia-Rong,Xiao, Wen-Jing
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supporting information
p. 6780 - 6783
(2018/06/26)
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- Rhenium-catalyzed deoxydehydration of renewable triols derived from sugars
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An efficient method for the catalytic deoxydehydration of renewable triols, including those obtained from 5-HMF, is described. The corresponding unsaturated alcohols were obtained in good yields using simple rhenium(vii)oxide under neat conditions and ambient atmosphere at 165 °C.
- Wozniak, Bartosz,Li, Yuehui,Tin, Sergey,De Vries, Johannes G.
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supporting information
p. 4433 - 4437
(2018/10/17)
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- Preparation method of 3-butene-1-ol
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The invention relates to a preparation method of 3-butene-1-ol. The preparation method comprises the following steps: (1) dissolving chloroethylene into a solvent so as to generate a Grignard reagent,namely vinyl magnesium chloride under the effect of an initiator; (2) adding ethylene oxide into the Grignard reagent at 10 DEG C below zero-10 DEG C, so as to generate a substitution product; and (3) finally carrying out acidic hydrolysis on the substitution product, so as to obtain 3-butene-1-ol. The preparation method has the beneficial effects that the adopted raw materials are relatively cheap, reaction conditions are relatively mild, and the operation time is short; and prepared 3-buten-e1-ol is high in purity and can completely meet the requirements on the use as a drug or a perfume intermediate.
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Paragraph 0028-0042
(2018/11/22)
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- Ru-Photoredox-Catalyzed Decarboxylative Oxygenation of Aliphatic Carboxylic Acids through N-(acyloxy)phthalimide
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Decarboxylative aminoxylation of aliphatic carboxylic acid derivatives with (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) in the presence of ruthenium photoredox catalysis is reported. The key transformation entails a highly efficient photoredox catalytic cycle using Hantzsch ester as a reductant. The ensuing alkoxyamine can be readily converted to the corresponding alcohol in one pot, representing an alternative approach to access aliphatic alcohols under photoredox conditions.
- Zheng, Chao,Wang, Yuting,Xu, Yangrui,Chen, Zhen,Chen, Guangying,Liang, Steven H.
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supporting information
p. 4824 - 4827
(2018/08/24)
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- 3-buten-1-ol
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The invention discloses a 3-butene-1-ol. The 3-butene-1-ol is prepared through the following steps: (1) DMF and 1,4-dibromobutane are pumped into a reaction kettle; (2) anhydrous dipotassium hydrogenphosphate is added; stirred, heated to reflux, after refluxing, anhydrous dipotassium phosphate is distillated, and crude products are collected; (3) the crude products are pumped into the reaction kettle, anhydrous sodium acetate is added, heat preservation reaction is conducted after heating up, sampling and detection are conducted; (4) after the detection is qualified, liquid caustic soda is added, stirred, after sampling and detection are qualified again, temperature is reduced to room temperature, methylene chloride is added for extraction, an organic layer mergers, rectification is conducted to remove methylene chloride to obtain the crude products; (5) the crude products are sent to a rectifying tower for rectification to obtain the 3-butene-1-ol; (6) kettle residue and stratified water layers are barreled or recycled. The 3-butene-1-ol has the advantages that an adopted preparation process not only has the high product selectivity and yield, easy availability of raw materials and safe operation, but also overcomes the disadvantages of the prior art such as high temperature and high pressure, low conversion rate, and difficult separation of products, and the obtained products have higher purity.
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Paragraph 0050-0056; 0061-0067; 0073-0079
(2018/06/26)
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- Selective production of 1,3-butadiene in the dehydration of 1,4-butanediol over rare earth oxides
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Vapor-phase dehydration of 1,4-butanediol and 3-buten-1-ol to produce 1,3-butadiene was investigated over rare earth oxides such as Lu2O3, Yb2O3, Tm2O3, Er2O3, and Sc1.0Yb1.0O3. In the dehydration of 3-buten-1-ol, heavy rare earth oxides such as Lu2O3, Yb2O3, and Er2O3 showed high catalytic performance for the selective formation of 1,3-butadiene with producing small amount of propylene whereas acidic catalysts such as alumina decomposed 3-buten-1-ol into propylene. In particular, over Yb2O3 calcined at 800 °C, 3-buten-1-ol was converted with a yield of 1,3-butadiene higher than 95% at 340 °C. In the dehydration of 1,4-butanediol, furthermore, we developed an efficient catalytic system: 1,3-butadiene was produced via an intermediate, 3-buten-1-ol, over Yb2O3 with an excellent yield of 96% at 360 °C and a high contact time of 2.26 h. Yb2O3 successfully inhibited the major side reaction such as decomposition of 3-buten-1-ol to propylene and provided the selective production of 1,3-butadiene from 1,4-butanediol.
- Wang, Yuchao,Sun, Daolai,Yamada, Yasuhiro,Sato, Satoshi
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- Production of homoallyl (by machine translation)
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1, 4 - butanediol 3 - butene -1 - ol [to] a dehydration reaction of the manufacturing method, without the use of expensive rare earth oxide or the like, using an inexpensive catalyst while suppressing the formation of byproducts, 3 - butene -1 - ol efficiently producing method. [Solution] the presence of the catalyst, by a dehydration reaction, 3 - 1, 4 - butanediol -1 - butene produced ol, as a catalyst, the catalyst components carried on the zirconium oxide and calcium oxide and zirconium oxide in a ratio of calcium oxide to the total weight of the monoclinic 0.1 weight % or more to less than 12% by weight with, 0.1 weight % or more weight percentage is less than 6% zirconium oxide carrying simultaneously impregnated catalyst. [Drawing] no (by machine translation)
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Paragraph 0031-0048
(2017/12/08)
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- Zeolite-Catalyzed Formaldehyde–Propylene Prins Condensation
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Prins condensation of formaldehyde with propylene to form 3-buten-1-ol is investigated using microporous solid acid catalysts. Zn/H-beta shows high conversion but leads to a broad product distribution composed primarily of pyrans. Mechanistic studies revealed that 3-buten-1-ol reacts via Prins cyclization or dehydrate to 1,3-butadiene that further reacts with formaldehyde via a hetero-Diels–Alder reaction. These secondary reactions are suppressed over ZSM-5 catalysts: 3-buten-1-ol is the predominant product over H-ZSM-5 zeolite under all conditions investigated. 3-Buten-1-ol selectivity of up to 75 % is achieved. In a second step 3-buten-1-ol dehydrates at temperatures as low as 423 K, forming 1,3-butadiene. Although Br?nsted acid sites are the primary catalytic sites, ion exchange of ZnII increases the overall rate and 3-buten-1-ol selectivity. H-ZSM-5 showed significant differences in reactivity and selectivity as a function of the Si/Al ratio; optimal catalytic properties were observed within Si/Al=40–140.
- Vasiliadou, Efterpi S.,Gould, Nicholas S.,Lobo, Raul F.
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p. 4417 - 4425
(2017/11/20)
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- Nano-flowered Ce@MOR hybrids with modulated acid properties for the vapor-phase dehydration of 1,3-butanediol into butadiene
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A series of Ce@MOR hybrids based on CeOx nanoparticles (1-2.5 nm) encapsulated in mordenite exhibiting a genuine flower-like morphology were prepared by simple hydrothermal synthesis. The cerium content in the catalysts could be easily tuned by adjusting the Si:Al:Ce composition of the preformed gel, affecting the textural properties and the density of acid sites of the catalysts. The genesis of acid sites with medium strength was directly correlated to the catalytic activity for the vapor-phase dehydration of 1,3-butanediol into butadiene. A Ce@MOR hybrid with a Si/Ce atomic ratio of 50 displayed a superior activity and selectivity compared to the parent MOR at a comparable Si/Al atomic ratio (10), as well as to control Ce-MOR catalysts post-synthesized by incipient wetness impregnation from the parent mordenite. A higher density of Br?nsted acid sites with medium strength induced by encapsulated CeOx nanoparticles was argued as the main reason for such an enhanced catalytic performance.
- Fang, Lin,Jing, Fangli,Lu, Jingya,Hu, Bingwen,Pera-Titus, Marc
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supporting information
p. 4610 - 4621
(2017/10/13)
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- METHOD FOR PRODUCING UNSATURATED ALCOHOL AND CATALYST
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PROBLEM TO BE SOLVED: To provide a method for the selective production of allyl type unsaturated alcohol from 1,3-diol. SOLUTION: As shown in the following reaction formula, a catalyst comprising zirconium oxide (ZrO2) and calcium oxide (CaO) acts on diol, to produce allyl type unsaturated alcohol (where R1-R4 independently represent H, a C1-5 alkyl group or the like). SELECTED DRAWING: None COPYRIGHT: (C)2017,JPOandINPIT
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Paragraph 0038; 0043
(2017/07/31)
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- MANUFACTURING METHOD OF UNSATURATED ALCOHOL AND CATALYST
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PROBLEM TO BE SOLVED: To provide a method for selectively manufacturing allyl type unsaturated alcohol form a 1,3-diol type raw material. SOLUTION: There is provided a manufacturing method of aimed allyl type unsaturated alcohol by making zirconia having total percentage content of a fluorite type tetragonal crystal and a fluorite type cubic crystal in an X-ray diffraction to diol represented by the formula (1) of 70% or more, containing at least one kind of dopant selected from alkali earth elements and rare earth elements and total content of the dopant atom to 1 mol of zirconium atom of 0.01 to 0.5 mol act and selectively proceeding one molecule dehydration. In the formula, R1 to R4 are each independently H, a C1 to 5 alkyl group or a C6 to 12 aryl group. SELECTED DRAWING: None COPYRIGHT: (C)2017,JPO&INPIT
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Paragraph 0062; 0063
(2017/05/10)
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- MANUFACTURING METHOD OF DIENE COMPOUND
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PROBLEM TO BE SOLVED: To provide a method for manufacturing a corresponding diene compound from 1,3-diol type raw material, loss in generation of by-product (impurities) impossible to reuse as a raw material. SOLUTION: There is provided a method for manufacturing a diene compound represented by the formula (3) by a first dehydration process for manufacturing unsaturated alcohol from a diol compound with dopant-containing zirconia containing one or more kind of dopant selected from an alkali earth element and a rear earth element with 0.010 to 0.500 mol of total dopant to 1 mol of zirconium atom as a catalyst and a second dehydrating process to manufacture the diene compound from unsaturated alcohol in presence of a dehydration catalyst consisting of one or more kind of compound selected from metal inorganic salt, metal oxide or inorganic acid. (3), R1 to R6 are each independently a C1 to 5 alkyl group or a C6 to 12 aryl group. SELECTED DRAWING: None COPYRIGHT: (C)2018,JPOandINPIT
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Paragraph 0086; 0087
(2018/04/10)
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- PROCESS FOR PRODUCING DIENE COMPOUND
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PROBLEM TO BE SOLVED: To provide a process for efficiently producing a corresponding diene compound from a 1,3-diol type raw material in which the formation of a byproduct that is impossible to be reused as a raw material, is small. SOLUTION: Provided is a process for producing diene compound in which a first dehydration step of producing an unsaturated alcohol from a diol compound represented by formula (1) by using a composite metal oxide having defect fluorite type crystalline structure or pyrochlore type crystalline structure, and a second dehydration step of carrying out dehydration reaction of the unsaturated alcohol in the presence of a dehydration catalyst comprising at least one selected from a metal phosphate, a metal condensed phosphate, a metal hydrochloride, an oxide of a typical metal or an inorganic acid to produce a diene compound, are implemented. SELECTED DRAWING: None COPYRIGHT: (C)2018,JPOandINPIT
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Paragraph 0088-0090
(2018/06/30)
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- Vapor-phase catalytic dehydration of 1,4-butanediol to 3-buten-1-ol over modified ZrO2 catalysts
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Vapor-phase catalytic dehydration of 1,4-butanediol (1,4-BDO) was investigated over modified ZrO2catalysts. In the dehydration of 1,4-BDO over monoclinic ZrO2(m-ZrO2), an unsaturated alcohol, 3-buten-1-ol (3B1OL), was produced together with tetrahydrofuranand γ-butyrolactone. Among alkaline earth metal oxide modifiers, CaO with an appropriate content significantly enhanced the 3B1OL selectivity of m-ZrO2. The modification of CaO was more efficient over m-ZrO2than tetragonal ZrO2. CO2-TPD measurements reveal that CaO supported on m-ZrO2calcined at 800?°C or higher generated new basic sites, which are attributed from Ca-O-Zr hetero-linkages, for the effective formation of 3B1OL from 1,4-BDO. In order to create more Ca-O-Zr hetero-linkages on the m-ZrO2surface efficiently, additional ZrO2was loaded on m-ZrO2together with CaO via a co-impregnation method. At an appropriate weight ratio of CaO/ZrO2?=?7/2 loaded on m-ZrO2, both the 1,4-BDO conversion and the 3B1OL selectivity were enhanced greatly. Especially, the 3B1OL selectivity exceeded 90% at 350?°C.
- Duan, Hailing,Hirota, Tomoya,Ohtsuka, Shota,Yamada, Yasuhiro,Sato, Satoshi
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- Selective Cobalt-Catalyzed Reduction of Terminal Alkenes and Alkynes Using (EtO)2Si(Me)H as a Stoichiometric Reductant
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While attempting to effect Co-catalyzed hydrosilylation of β-vinyl trimethylsilyl enol ethers, we discovered that, depending on the silane, solvent, and the method of generation of the reduced cobalt catalyst, a highly efficient and selective reduction or hydrosilylation of an alkene can be achieved. This paper deals with this reduction reaction, which has not been reported before in spite of the huge research activity in this area. The reaction, which uses the air-stable [2,6-bis(aryliminoyl)pyridine)]CoCl2 activated by 2 equiv of NaEt3BH as the catalyst (0.001-0.05 equiv) and (EtO)2SiMeH as the hydrogen source, is best run at ambient temperature in toluene and is highly selective for the reduction of simple unsubstituted 1-alkenes and the terminal double bonds in 1,3- and 1,4-dienes, β-vinyl ketones, and silyloxy dienes. The reaction is tolerant of various functional groups such as bromide, alcohol, amine, carbonyl, di- or trisubstituted double bonds, and water. Highly selective reduction of a terminal alkyne to either an alkene or alkane can be accomplished by using stoichiometric amounts of the silane. Preliminary mechanistic studies indicate that the reaction is stoichiometric in the silane and both hydrogens in the product come from the silane.
- Raya, Balaram,Biswas, Souvagya,Rajanbabu
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p. 6318 - 6323
(2016/09/09)
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- Synthesis of highly selective nano-structured functionalized SBA-15 metformin palladium composite catalyst in partial hydrogenation of alkynes
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In this research, a heterogeneous Nano-Structured functionalized SBA-15 metformin palladium composite catalyst is reported for the selective hydrogenation of alkynes. In the first place, A series of the heterogeneous mesoporous SBA-15 metformin palladium catalyst were prepared and afterwards the condition and the ratio of used materials were optimized to give rise a suitable high performance catalyst. The final nano-structured catalyst was characterized by X-ray powder diffraction, BET surface area, FT-IR spectrophotometer, Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) and served in partial hydrogenation of different alkynes, with high selectivity and high yield. The liquid phase hydrogenation was conducted under mild condition of room temperature and atmospheric pressure. The reactions were monitored every half an hour by gas chromatography and all of them were completed during 4-6 hours. The products were characterized by 1H-NMR, 13C-NMR, FT-IR, and Mass Spectrometry (MS) that strongly confirmed the (Z)-double bond configuration of produced alkenes. This prepared catalyst is competitive with the best palladium catalysts known for the selective liquid phase hydrogenation of alkynes and can be easily recovered and regenerated with keeping high activity and selectivity over multiple cycles with a simple regeneration procedure.
- Kojoori, Reza Kia
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p. 3144 - 3149
(2016/11/18)
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- Partial hydrogenation of alkynes on highly selective nano-structured mesoporous silica MCM-41 composite catalyst
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In this research, we have developed a silica MCM-41/Metformin/Pd (II) nano composite catalyst for the selective hydrogenation of alkynes to the corresponding (Z)-alkenes under a mild condition of atmospheric pressure and room temperature. Firstly, functionalized Si-MCM-41 metformin catalyst with the optimum performance was prepared. Then, the synthesized catalyst was elucidated by X-ray powder diffraction, BET surface area, FT-IR spectrophotometer, Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) and applied in partial hydrogenation of different alkynes, with high selectivity and high yield. The products were characterized by 1H-NMR, 13C-NMR, FT-IR, and Mass Spectrometry (MS) that strongly approved the (Z)-double bond configuration of produced alkenes. This prepared catalyst is competitive with the best palladium catalysts known for the selective liquid phase hydrogenation of alkynes and can be easily recovered and regenerated with keeping high activity and selectivity over at least three cycles with a simple regeneration procedure.
- Kojoori, Reza Kia
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p. 1121 - 1128
(2017/01/25)
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- Hydroalumination of terminal β-acetylene alcohols with lithium aluminum hydride
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Hydrogenation of terminal β-acetylene alcohols with lithium aluminum hydride in THF has afforded homoallylic alcohols. Decomposition of the intermediate organoaluminum complex with deuterated water, iodine, or pyridinium dibromide has evidenced about the non-regioselective hydride attack at the triple bond.
- Garibyan,Makaryan,Ogannisyan,Chobanyan
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p. 267 - 272
(2016/04/20)
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- MANUFACTURING METHOD OF OLEFIN COMPOUND, ALLOY PARTICLE AND CATALYST CONTAINING THE SAME
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PROBLEM TO BE SOLVED: To provide a manufacturing method of an olefin compound using a catalyst capable of inhibiting corrosion of a reaction vessel, high in degree of freedom of a substrate selectivity and easy to separate and collect from the olefin compound which is a product material. SOLUTION: There is provide a manufacturing method of an olefin compound (3) by reacting an olefin compound (1) and an aldehyde compound or a polymer thereof in a presence of a catalyst having a B2 type or L12 type crystal structure constituted by Cu and Pd or a L10 type crystal structure constituted by Cu and Au and having average particle diameter of 0.5 to 1000 nm. SELECTED DRAWING: None COPYRIGHT: (C)2016,JPOandINPIT
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Paragraph 0147; 0148
(2017/03/25)
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- ReOx/TiO2: A Recyclable Solid Catalyst for Deoxydehydration
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Deoxydehydration (DODH) enables the transformation of two adjacent hydroxyl functions into a C-C double bond: e.g., facilitating synthesis of 1,3,5-hexatriene from sorbitol. Here we report the first stable heterogeneous catalyst for DODH based on ReOx supported on TiO2. ReOx/TiO2 exhibits not only catalytic activity and selectivity comparable to those of previously described molecular rhenium catalysts but also excellent stability without deactivation over at least six consecutive runs. X-ray absorption spectroscopy (XAFS) measurements indicate a mixture of Re(VII), Re(IV), and Re(0) species at a ratio of 0.47:0.27:0.25, remaining comparatively stable during catalysis.
- Sandbrink, Lennart,Klindtworth, Elisabeth,Islam, Husn-Ubayda,Beale, Andrew M.,Palkovits, Regina
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p. 677 - 680
(2016/02/18)
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- One-Step Production of 1,3-Butadiene from 2,3-Butanediol Dehydration
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We report the direct production of 1,3-butadiene from the dehydration of 2,3-butandiol by using alumina as catalyst. Under optimized kinetic reaction conditions, the production of methyl ethyl ketone and isobutyraldehyde, formed via the pinacol–pinacolone rearrangement, was markedly reduced and almost 80 % selectivity to 1,3-butadiene and 1,3-butadiene could be achieved. The presence of water plays a critical role in the inhibition of oligomerization. The amphoteric nature of γ-Al2O3was identified as important and this contributed to the improved catalytic selectivity when compared with other acidic catalysts.
- Liu, Xi,Fabos, Viktoria,Taylor, Stuart,Knight, David W.,Whiston, Keith,Hutchings, Graham J.
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p. 12290 - 12294
(2016/08/24)
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- Core cross-linked micelles of polyphosphoester containing amphiphilic block copolymers as drug nanocarriers
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Poly(ethylene oxide)-b-polyphosphoester amphiphilic block copolymers are known to self-assemble into polymer micelles when dissolved in water. This work aims at reporting on the improvement of the stability of the micelles at high dilution by crosslinking the hydrophobic polyphosphoester micellar core. Typically, an unsaturated alkene side-chain was introduced onto the cyclic phosphate monomer according to a one-step reaction followed by its organocatalyzed polymerization initiated by a poly(ethylene oxide) macroinitiator. This strategy avoids the use of any organometallic compounds in order to facilitate the purification and meet the stringent requirements of biomedical applications. After self-assembly in water, the micelles were cross-linked by simple UV irradiation. These cross-linked micelles have then been loaded with doxorubicin to evaluate their potential as drug nanocarriers and monitor the impact of crosslinking on the release profile.
- Yilmaz, Z. Ergul,Zeynep, Ergul Yilmaz,Vanslambrouck,Cajot,Thiry,Debuigne,Lecomte,Jér?me,Riva
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p. 42081 - 42088
(2016/05/24)
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- Synthesis of C4 and C8 Chemicals from Ethanol on MgO-Incorporated Faujasite Catalysts with Balanced Confinement Effects and Basicity
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A new type of catalyst has been designed to adjust the basicity and level of molecular confinement of KNaX faujasites by controlled incorporation of Mg through ion exchange and precipitation of extraframework MgO clusters at varying loadings. The catalytic performance of these catalysts was compared in the conversion of C2 and C4 aldehydes to value-added products. The product distribution depends on both the level of acetaldehyde conversion and the fraction of magnesium as extraframework species. These species form rather uniform and highly dispersed nanostructures that resemble nanopetals. Specifically, the sample containing Mg only in the form of exchangeable Mg2+ ions has much lower activity than those in which a significant fraction of Mg exists as extraframework MgO. Both the (C6+C8)/C4 and C8/C6 ratios increase with additional extraframework Mg at high acetaldehyde conversion levels. These differences in product distribution can be attributed to 1) higher basicity density on the samples with extraframework species, and 2) enhanced confinement inside the zeolite cages in the presence of these species. Additionally, the formation of linear or aromatic C8 aldehyde compounds depends on the position on the crotonaldehyde molecule from which abstraction of a proton occurs. In addition, catalysts with different confinement effects result in different C8 products.
- Zhang, Lu,Pham, Tu N.,Faria, Jimmy,Santhanaraj, Daniel,Sooknoi, Tawan,Tan, Qiaohua,Zhao, Zheng,Resasco, Daniel E.
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p. 736 - 748
(2016/05/09)
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- MICROORGANISMS FOR PRODUCING 4C-5C COMPOUNDS WITH UNSATURATION AND METHODS RELATED THERETO
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The invention provides a non-naturally occurring microbial organism having a butadiene, crotyl alcohol, 2,4-pentadienoate, 3-buten-2-ol, or 3-buten-1-ol, pathway. The microbial organism contains at least one exogenous nucleic acid encoding an enzyme in a pathway. The invention additionally provides a method for producing butadiene, crotyl alcohol, 2,4-pentadienoate, 3-buten-2-ol, or 3-buten-1-ol,. The method can include culturing a butadiene, crotyl alcohol, 2,4-pentadienoate, 3-buten-2-ol, or 3-buten-1-ol-producing microbial organism, where the microbial organism expresses at least one exogenous nucleic acid encoding a pathway enzyme in a sufficient amount, and under conditions and for a sufficient period of time to produce butadiene, crotyl alcohol, 2,4-pentadienoate, 3-buten-2-ol, or 3-buten-1-ol.
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Paragraph 0015; 00101
(2016/01/25)
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- Synthesis of active tin: An efficient reagent for allylation reaction of carbonyl compounds
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High purity Sn(0) has been obtained as a result of reduction of SnO by sodium stannite (Na2SnO2) in aqueous solution. The process stands unique for the production of tin metal. The as-synthesized tin finds applications in synthetic organic chemistry as a reagent for the allylation of aldehydes and ketones in distilled water at room temperature to give rise to the corresponding homoallylic alcohols with high yield. The reaction occurs without the assistance of heat, ultrasonic vibration, co-solvents/co-reagents, etc. Enhancement of the reaction rate of allylation was observed in water rather than THF. The manipulation of allylation reaction becomes easy with active tin material.
- Sinha, Arun Kumar,Sil, Amit,Sasmal, Anup Kumar,Pradhan, Mukul,Pal, Tarasankar
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p. 1685 - 1690
(2015/03/30)
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- Dibutyltin oxide mediated diastereoselective cyclodehydration/sulfonylation of 1,2,4-triols
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Dibutyltin oxide (Bu2SnO) mediated cyclodehydration or sulfonylation of 1,2,4-triols is predictably diastereoselective depending on the steric bulk of the substituents at C4. A larger difference (ΔA-value >1 kcal/mol) leads to the syn-1,2,4-triols favouring cyclodehydration (78-85%) to form 3-hydroxytetrahydrofurans, with the anti-1,2,4-triols favouring monosulfonylation (66-87%). Triols from symmetrical ketones preferentially undergo cyclodehydration in high yield (>75%) due to a gem-disubstituent effect. Thus, the 1,2,4-triols derived from simple cyclic ketones also favour cyclodehydration to form spirocyclic 3-hydroxytetrahydrofurans in 72-79% yields.
- Gamedze, Makhosazana P.,Nkambule, Comfort M.
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supporting information
p. 1825 - 1829
(2015/03/30)
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- A new method for the preparation of non-terminal alkynes: Application to the total syntheses of tulearin A and C
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Lactones are known to react with the reagent generated in situ from CCl4 and PPh3 in a Wittig-type fashion to give gem-dichloro-olefin derivatives. Such compounds are now shown to undergo reductive alkylation on treatment with organolithium reagents RLi to furnish acetylene derivatives bearing the substituent R at their termini (R=Me, n-, sec-, tert-alkyl, silyl); the reaction can be catalyzed with either Cu(acac)2 or Fe(acac)3/1,2-diaminobenzene. Two alkynol derivatives prepared in this way from readily accessible lactone precursors served as the key building blocks for the total syntheses of the cytotoxic marine macrolides tulearin A (1) and C (2). The assembly of these fragile targets hinged upon ring closing alkyne metathesis (RCAM) followed by a formal trans-reduction of the resulting cycloalkynes via trans-hydrosilylation/protodesilylation.
- Lehr, Konrad,Schulthoff, Saskia,Ueda, Yoshihiro,Mariz, Ronaldo,Leseurre, Lucie,Gabor, Barbara,Fürstner, Alois
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supporting information
p. 219 - 227
(2015/02/19)
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- On the chemistry of ethanol on basic oxides: Revising mechanisms and intermediates in the lebedev and guerbet reactions
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A common way to convert ethanol into chemicals is by upgrading it over oxide catalysts with basic features; this method makes it possible to obtain important chemicals such as 1-butanol (Guerbet reaction) and 1,3-butadiene (Lebedev reaction). Despite their long history in chemistry, the details of the close inter-relationship of these reactions have yet to be discussed properly. Our present study focuses on reactivity tests, in situ diffuse reflectance infrared Fourier transform spectroscopy, MS analysis, and theoretical modeling. We used MgO as a reference catalyst with pure basic features to explore ethanol conversion from its very early stages. Based on the obtained results, we formulate a new mechanistic theory able to explain not only our results but also most of the scientific literature on Lebedev and Guerbet chemistry. This provides a rational description of the intermediates shared by the two reaction pathways as well as an innovative perspective on the catalyst requirements to direct the reaction pathway toward 1-butanol or butadiene.
- Chieregato, Alessandro,Ochoa, Juliana Velasquez,Bandinelli, Claudia,Fornasari, Giuseppe,Cavani, Fabrizio,Mella, Massimo
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p. 377 - 388
(2015/01/30)
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- Mild deprotection of PMB ethers using tert-butyl bromide
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A convenient and high yielding method for the cleavage and scavenging of p-methoxybenzyl protecting group of several alcohols using tert-butyl bromide in refluxing acetonitrile is described. Under these mild conditions other protecting groups such as acid sensitive allyl, benzyl, and Me3CPh2Si ethers, or isopropylidene acetals were unchanged. Interestingly, a selective alkoxy-PMB cleavage was observed in the presence of a PMB phenoxy ether.
- Rival, Nicolas,Albornoz Grados, Arantxa,Schiavo, Lucie,Colobert, Fran?oise,Hanquet, Gilles
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p. 6823 - 6826
(2015/11/27)
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- Conversion of diols by dehydrogenation and dehydration reactions on silica-supported copper catalysts
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The gas-phase conversion of a 1,3-polyol (1,3-butanediol) containing primary and secondary OH functions was studied on a series of copper-silica catalysts, ZCuSiO2 (Z = 1-25 wt.% Cu), and thoroughly characterized by several techniques such as BET surface area, TPR, XRD, N2O chemisorption, and UV-vis-DRS. The physicochemical properties of the ZCuSiO 2 catalysts depended on whether the metal loading was above or below the copper monolayer surface coverage (Z = 13.5 wt.% Cu). Copper species presenting different degrees of interaction with the silica support were detected. At low Z values Cu0 dispersion was high (D ≈ 40%) due to a predominant contribution of nano-sized Cu species (3 nm) which are difficult to reduce, but for Z > 13.5 wt.%, D abruptly dropped to 3-8% because of formation of larger tridimensional Cu clustered species (30 nm) that reduced at lower temperatures because of a decreased copper-silica interaction. On ZCuSiO2 catalysts, dehydrogenation of the 1,3-butanediol secondary OH function prevailed over that of the primary one and therefore valuable ketones were the main reaction products. Consecutively to dehydrogenation, dehydration and hydrogenation reactions also took place. Products of the tandem reaction were the β-hydroxy ketone (4-hydroxy-2-butanone), the α,β- unsaturated ketone (methyl vinyl ketone) and the saturated ketone (methyl ethyl ketone). A direct 1,3-butanediol dehydration pathway toward methyl ethyl ketone was also found. Reaction pathways were strongly dependent on the Cu loading and therefore on the kind of Cu species (isolated or clustered). When compared at similar conversion levels, selectivity to the dehydrogenation product 4-hydroxy-2-butanone increased with Z suggesting that on large Cu0 particles 4-hydroxy-2-butanone was released to the gas phase before being converted in consecutive steps. On the contrary, on highly dispersed Cu 0 crystals of low Cu loading catalysts, 1,3-butanediol was readily dehydrated giving the saturated ketone. Kinetically relevant reaction steps of 1,3-butanediol conversion by dehydrogenation and dehydration were promoted on Cu0 sites. Dehydration of the intermediate 4-hydroxy-2-butanone also occurred on Cu0 sites. Turnover rates were constant on Cu0 nano particles and slightly higher on clustered species.
- Torresi,Díez,Luggren,Di Cosimo
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p. 119 - 129
(2013/07/19)
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- Heterogeneous CaO-ZrO2 acid-base bifunctional catalysts for vapor-phase selective dehydration of 1,4-butanediol to 3-buten-1-ol
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A series of acid-base bifunctional CaO-ZrO2 catalysts was prepared simply by the impregnation method and evaluated for the vapour-phase dehydration of 1,4-butanediol (BDO). The effects of CaO content and calcination temperature on the catalytic properties of the CaO-ZrO2 catalysts were investigated. It was found that the catalyst with 12.5 wt% CaO and at a calcination temperature of 650°C exhibited favorable catalytic performance and good stability for the selective dehydration of BDO to 3-buten-1-ol (BTO). The maximum BTO selectivity and BDO conversion reached 68.9% and 94.6%, respectively. The formation of by-product, THF, was markedly suppressed. These catalysts were characterized by N2 physisorption, XRD, FT-IR spectra, NH3-TPD and CO2-TPD. The results indicated that the CaO-ZrO2 catalysts showed higher basicity density and similar acidity density compared to unmodified ZrO2 due to the formation of Ca-O-Zr Hetero-linkage by CaO introduction. The catalytic performance depended on the coexistence of acidic and basic sites on the surface of catalysts.
- Zhang, Qian,Zhang, Yin,Li, Haitao,Gao, Chunguang,Zhao, Yongxiang
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p. 233 - 239
(2013/08/23)
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- Preparation of Er2O3 nanorod catalyst without using organic additive and its application to catalytic dehydration of 1,4-butanediol
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Er2O3 nanorods were successfully prepared with hydrothermal treatment without using organic additives such as surfactant, fatty acid, or alcohol. Er2 O3 nanorods were obtained under high temperature and/or long reaction times. Er2O3 nanorods mainly exposed {440} and {400} facets on the surface. Er2O3 nanorods showed excellent catalytic activity compared to commercial Er2O3 nanoparticles in the dehydration of 1,4-butanediol to produce 3-buten-1-ol.
- Sato, Fumiya,Yamada, Yasuhiro,Sato, Satoshi
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supporting information; scheme or table
p. 593 - 594
(2012/08/08)
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- Unprecedented synergistic effects between weak Lewis and Bronsted acids in Prins cyclization
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Novel synergistic effects between Lewis and Bronsted acids in Prins cyclization are reported. Non-reactive Lewis acids and non-reactive Bronsted acids, which failed to perform Prins cyclization when used alone, have shown remarkable synergistic effects wh
- Borkar, Prashant,Van De Weghe, Pierre,Reddy, B. V. Subba,Yadav,Gree, Rene
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supporting information; experimental part
p. 9316 - 9318
(2012/09/22)
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- Dehydration of 1,5-pentanediol over bixbyite Sc2-xYb xO3 catalysts
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Vapor-phase dehydration of 1,4- and 1,5-alkanediols was investigated over three scandium ytterbium mixed oxides, Sc2-xYbxO 3 (x = 0.5, 1.0, and 1.5), to produce the corresponding unsaturated alcohols. In the dehydration of
- Sato, Fumiya,Sato, Satoshi
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p. 129 - 133
(2013/01/13)
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- Total synthesis of tulearin C
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With the help of the smaller brother: Although alkyne metathesis will always be the little brother of alkene metathesis, it allows problems to be solved that are currently beyond reach of the more famous sibling. This notion is exemplified by the tulearin macrolides, which could only be selectively forged by ring-closing alkyne metathesis (RCAM)/transreduction using the latest generation of alkyne metathesis catalysts.
- Lehr, Konrad,Mariz, Ronaldo,Leseurre, Lucie,Gabor, Barbara,Fuerstner, Alois
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scheme or table
p. 11373 - 11377
(2012/01/11)
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- Co-metathesis of ethylene and olefinic compounds in ionic liquids
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Tungsten(VI) chloride dissolved in the ionic liquids is capable of catalyzing metathesis of 4-octene and co-metathesis of 4-penten-1-ol with ethylene; the latter reaction is preceded by double bond shift in the starting alkenol.
- Greish, Alexander A.,Kustov, Leonid M.,Vasnev, Alexander V.
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experimental part
p. 329 - 330
(2012/02/01)
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- Preparation, characterization, and kinetic evaluation of dendrimer-derived bimetallic Pt-Ru/SiO2 catalysts
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A series of silica-supported Pt, Ru, and Pt-Ru catalysts has been synthesized using dendrimer-metal nanocomposite (DMN) precursors prepared by both co- and sequential complexation with metal salts. The catalysts have been characterized by several techniqu
- Liu, Dongxia,Lopez-De Jesus, Yaritza M.,Monnier, John R.,Williams, Christopher T.
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experimental part
p. 376 - 387
(2010/04/02)
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