- Asymmetric Catalysis by Vitamin B12. The isomerization of Achiral Epoxides to Optically Active Allylic Alcohols
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Achiral epoxides are isomerized to optically active allylic alcohols under the influence of catalytical amounts of cob(I)alamin in protic polar solvents.
- Su, Heng,Walder, Lorenz,Zhang, Zhong-da,Scheffold, Rolf
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- Evidence for a Concerted SN2' Mechanism in the Gas-Phase Acid-induced Nucleophilic Substitutions on Allylic Substrates
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Gas phase nucleophilic substitution on oxygen-protonated but-1-en-3-ol and trans-but-2-en-1-ol by methanol proceeds via the concerted SN2' mechanism in competition with the classical SN2 mechanism.
- Dezi, Emanuela,Lombardozzi, Antonietta,Pizzabiocca, Adriano,Renzi, Gabriele,Speranza, Maurizio
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- Active site structure of a lithium phosphate catalyst for the isomerization of 2,3-epoxybutane to 3-buten-2-ol
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Basic lithium phosphate (B-LPO) catalyst selectively produces unsaturated alcohols from epoxides. The catalytic activity of B-LPO is known to originate from appropriate acidic-basic properties, but no details were available on the structure of the active site. In this study, experimental methods and DFT calculations were performed in an attempt to identify the active surface structure of B-LPO for the isomerization of 2,3-epoxybutane to 3-buten-2-ol. The experimental results showed that exchanged Na ions in B-LPO suppressed the formation of an acid-catalyzed by-product (methyl ethyl ketone). In addition, H2O had a negative effect on the formation of 3-buten-2-ol due to the preoccupation of the active site. DFT calculations in conjunction with these experimental observations showed that the most plausible active surface for the formation of 3-buten-2-ol is the (001) surface of LPO whose acidic proton is exchanged with Na atom. On this surface, the under-coordinated Li atoms and the surface P[dbnd]O groups are exposed, and these play a role in activating the C–O bond of an epoxide ring, and in receiving a proton from the terminal carbon, respectively.
- Kim, Tae Yong,Song, Chyan Kyung,Yun, Yang Sik,Yun, Danim,Han, Jeong Woo,Yi, Jongheop
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- THE cis REDUCTION OF 4-(TRIMETHYLSILYL)-3-BUTYN-2-OL WITH LITHIUM ALUMINIUM HYDRIDE
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A systematic study led to a method for the preparation of (Z)-4-(trimethylsilyl)-3-buten-2-ol (2) in at least 99percent purity by the reduction of the alkyne 4-(trimethylsilyl)-3-butyn-2-ol (1) with lithium aluminium hydride (LAH) as a clear solvate in ether.
- Mancini, Michael L.,Honek, John F.
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- Probing Molecular Motion and Chemical Reactions inside the Chiral Tri-o-thymotide Clathrate Cavity by Solid State NMR Techniques
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Solid state NMR techniques offer a non-destructive alternative to wet chemistry methods in following enantiomeric excess and reactions in chiral clathrates, and show that the two optically distinct populations, one of which cannot be defined by X-ray diffraction, can be characterized by their distinct dynamic behaviour.
- Facey, Glenn,Ripmeester, John A.
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- Regio- And Enantioselective Iridium-Catalyzed Amination of Alkyl-Substituted Allylic Acetates with Secondary Amines
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Robust air-stable cyclometalated π-allyliridium C,O-benzoates modified by (S)-tol-BINAP catalyze the reaction of secondary aliphatic amines with racemic alkyl-substituted allylic acetates to furnish products of allylic amination with high levels of enantioselectivity. Complete branched regioselectivities were observed despite the formation of more highly substituted C-N bonds.
- Jung, Woo-Ok,Krische, Michael J.,Migliozzi, Madyson M.,Stivala, Craig E.,Yoo, Minjin,Zbieg, Jason R.
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supporting information
(2021/12/27)
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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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- 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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- PROCESS FOR PRODUCING DIENES
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A process for producing a diene, preferably a conjugated diene, more preferably 1,3-butadiene, comprising dehydrating at least one alkenol in the presence of at least one catalytic material comprising at least one acid catalyst based on silica (SiO2) and alumina (AI2O3), preferably a silica-alumina (SiO2-Al2O3), said catalyst having an alumina content (Al2O3) lower than or equal to 12% by weight, preferably between 0.1% by weight and 10% by weight, with respect to the catalyst total weight, said alumina content being referred to the catalyst total weight without binder, and a pore modal diameter between 9 nm and 170 nm, preferably between 10 nm and 150 nm, still more preferably between 12 nm and 120 nm. Preferably, said alkenol can be obtained directly from biosynthetic processes, or by catalytic dehydration processes of at least one diol, preferably a butanediol, more preferably 1,3-butanediol, still more preferably bio-1,3-butanediol, deriving from biosynthetic processes. Preferably, said 1,3-butadiene is bio-1,3-butadiene.
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Page/Page column 30-34
(2021/06/26)
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- Dehydration of 2,3-butanediol to produce 1,3-butadiene over Sc2O3 catalyst prepared through hydrothermal aging
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Vapor-phase catalytic dehydration of 2,3-butanediol (2,3-BDO) to form 1,3-butadiene (BD) via 3-buten-2-ol (3B2OL) was studied over various single metal oxide catalysts. Among the catalysts, Sc2O3 prepared under hydrothermal (HT) conditions at 200 °C followed by 800 °C calcination showed the most excellent catalytic activity. The crystallization of precursor ScOOH during HT aging noticeably enhances the catalytic activity of the resulting Sc2O3 for the formation of 3B2OL in the dehydration of 2,3-BDO. The formation rate of 3B2OL from 2,3-BDO over the HT-aged Sc2O3 was twice as high as Sc2O3 without HT aging. Calcination temperatures of Sc2O3 are also important: calcination at 800 °C is efficient for the selective formation of 3B2OL from 2,3-BDO. The HT-aged Sc2O3 also showed an excellent catalytic activity for the formation of BD with the yield higher than 80% in the dehydration of 2,3-BDO at 411 °C.
- Nakazono, Kazuki,Sato, Satoshi,Takahashi, Ryoji,Yamada, Yasuhiro
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- Asymmetric Synthesis of γ-Secondary Amino Alcohols via a Borrowing-Hydrogen Cascade
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The borrowing-hydrogen (or hydrogen autotransfer) process, where the catalyst dehydrogenates a substrate and formally transfers the H atom to an unsaturated intermediate, is an atom-efficient and environmentally benign transformation. Described here is an example of an asymmetric borrowing-hydrogen cascade for the formal anti-Markovnikov hydroamination of allyl alcohols to synthesize optically enriched γ-secondary amino alcohols. By exploiting the Ru-(S)-iPrPyme catalyst with minimal stereogenicity, a cascade process including dehydrogenation, conjugate addition, and asymmetric reduction was developed. The mild conditions, functional group tolerance, and broad substrate scope (54 examples) demonstrate the synthetic practicality of the catalytic system.
- Chang, Xiaoyong,Chen, Fumin,He, Dongxu,Jin, Ming Yu,Pan, Yupeng,Xing, Xiangyou,You, Yipeng
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supporting information
p. 7278 - 7283
(2020/10/02)
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- PROCESS FOR BIO-1,3-BUTANEDIOL PURIFICATION FROM A FERMENTATION BROTH
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Process for bio-1,3-butanediol purification from a fermentation broth comprising the following steps: (a) subjecting the fermentation broth to separation; (b) subjecting the product obtained in step (a) to treatment with ion-exchange resins; (c) subjecting the product obtained in step (b) to a first evaporation; (d) subjecting the product obtained in step (c) to a second evaporation; (e) subjecting the product obtained in step (d) to a third evaporation, obtaining purified bio-1,3-butanediol. Said purified bio-1,3-butanediol may advantageously be used for the production of bio- 1,3-butadiene, which in turn may advantageously be used as a monomer or as an intermediate in the production of elastomers and (co)polymers.
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Page/Page column 45; 47-49
(2020/04/25)
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- Rh-Catalyzed Regioselective Dialkylation of Cage B-H bonds in o-Carboranes: Oxidative Heck Reactions via an Enol Isomerization
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In the presence of a carboxylic acid directing group, Rh-catalyzed regioselective directed dialkylation of B(4,5)-H bonds in o-carboranes and oxidative coupling with allylic alcohols is reported. This strategy constructs a series of 4,5-dialkylated o-carboranes in good yields with excellent regioselectivity. A possible catalytic cycle is proposed that involves a tandem sequence of Rh-catalyzed cage B-H activation, alkene insertion, selective β-H elimination, enol isomerization, and decarboxylation.
- Wang, Qian,Tian, Song,Zhang, Chuyi,Li, Jiangwei,Wang, Zhixuan,Du, Yongmei,Zhou, Ling,Lu, Jian
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supporting information
p. 8018 - 8021
(2019/10/19)
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- 2,3-Butanediol dehydration catalyzed by silica-supported alkali phosphates
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Characterization of acid-base centers and catalytic dehydration of 2,3-butanediol (BDO) was performed over a wide range of silica-supported alkali phosphates (M_P/SiO2; M = Na, K, Cs; M:P = 0.5–3 mol:mol). Selectivity to 1,3-butadiene (BD) and 3-butene-2-ol (3B2OL) formed by elimination correlates with the densities of conjugated acid-base pairs and increases in the order Na ??M+ moieties. Isolated Br?nsted acid centers are probably silica grafted phosphoric acid molecules at low M/P and –PO(OH)2 end groups of oligophosphates at M/P > 1.5. Deactivation rate increases with the increase of M/P ratio in order Na K Cs. Deactivation patterns imply that sites responsible for elimination are active in dehydrative epoxidation. Dehydration of 3B2OL smoothly proceeds to BD, but the catalysts deactivate faster compared to BDO dehydration.
- Kim, Wooyoung,Shin, Wookyun,Lee, Kyoung Jun,Cho, YongSeok,Kim, Hyung Soon,Filimonov, Igor N.
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p. 148 - 163
(2018/11/26)
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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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- DEHYDRATION OF DIOLS
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Provided is a method for producing an alkene. The method comprises a step of converting a compound (I) comprising at least two hydroxyl functions into a compound (II) comprising at least two alkenyl functions with cerium oxide particles as catalyst. It notably permits the conversion of 1,3-butanediol,1,4-butanediol into butadiene.
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Page/Page column 15; 16
(2018/03/25)
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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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- A new anthraquinoid ligand for the iron-catalyzed hydrosilylation of carbonyl compounds at room temperature: New insights and kinetics
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The reaction of 1-((2-(pyridin-2-yl)ethyl)amino)anthraquinone with either Fe(HMDS)2 or Li(HMDS)/FeCl2 allowed the preparation of a new anthraquinoid-based iron(ii) complex active in the hydrosilylations of carbonyls. The new complex Fe(2)2 was characterized by single-crystal X-ray diffraction, infrared spectroscopy, NMR, and high resolution mass spectrometry (electrospray ionization). Superconducting quantum interference device (SQUID) magnetometry established no spin crossover behavior with an S = 2 state at room temperature. This complex was determined to be an effective catalyst for the hydrosilylation of aldehydes and ketones, exhibiting turnover frequencies of up to 63 min-1 with a broad functional group tolerance by just using 0.25 mol% of the catalyst at room temperature, and even under solvent-free conditions. The aldehyde hydrosilylation makes it one of the most efficient first-row transition metal catalysts for this transformation. Kinetic studies have proven first-order dependences with respect to acetophenone and Ph2SiH2 and a fractional order in the case of the catalyst.
- Raya-Barón, álvaro,Galdeano-Ruano, Carmen P.,O?a-Burgos, Pascual,Rodríguez-Diéguez, Antonio,Langer, Robert,López-Ruiz, Rosalía,Romero-González, Roberto,Kuzu, Istemi,Fernández, Ignacio
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supporting information
p. 7272 - 7281
(2018/06/04)
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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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- Rhodium-Catalyzed Asymmetric N?H Functionalization of Quinazolinones with Allenes and Allylic Carbonates: The First Enantioselective Formal Total Synthesis of (?)-Chaetominine
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An unprecedented asymmetric N?H functionalization of quinazolinones with allenes and allylic carbonates was successfully achieved by rhodium catalysis with the assistance of chiral bidentate diphosphine ligands. The high efficiency and practicality of this method was demonstrated by a low catalyst loading of 1 mol % as well as excellent chemo-, regio-, and enantioselectivities with broad functional group compatibility. Furthermore, this newly developed strategy was applied as key step in the first enantioselective formal total synthesis of (?)-chaetominine.
- Zhou, Yirong,Breit, Bernhard
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supporting information
p. 18156 - 18160
(2017/12/13)
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- Vapor-phase catalytic dehydration of 2,3-butanediol to 3-buten-2-ol over ZrO2 modified with alkaline earth metal oxides
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Vapor-phase catalytic dehydration of 2,3-butanediol (2,3-BDO) to produce 3-buten-2-ol (3B2OL) was investigated over several monoclinic ZrO2 (m-ZrO2) catalysts modified with alkaline earth metal oxides (MOs), such as SrO, BaO, and MgO, to compare with the previously reported CaO/m-ZrO2. It was found that these modifiers enhanced the 3B2OL formation to the same level as CaO did by loading an appropriate MO content. Among all the tested catalysts, the BaO/m-ZrO2 calcined at 800?°C with a low BaO content (molar ratio of BaO/ZrO2?=?0.0452) shows the highest 2,3-BDO conversion (72.4%) and 3B2OL selectivity (74.4%) in the initial stage of 5?h at 350?°C. In order to characterize those catalysts, their catalytic activities, crystal structures, and basic properties were studied in detail. In X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) experiment, it was elucidated that highly dispersed M-O-Zr (M?=?Ca, Sr, and Ba) hetero-linkages were formed on the surface by loading these MOs onto m-ZrO2 with an appropriate content and then calcining at 800?°C. It can be concluded that the M-O-Zr hetero-linkages generate the proper base-acid balance for the efficient formation of 3B2OL from 2,3-BDO.
- Duan, Hailing,Yamada, Yasuhiro,Kubo, Shingo,Sato, Satoshi
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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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- METHOD OF PREPARING 1,3-BUTADIENE AND METHYL ETHYL KETONE FROM 2,3-BUTANEDIOL USING ADIABATIC REACTOR
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Disclosed is a method of preparing 1,3-butadiene and methyl ethyl ketone from 2,3-butanediol, including: a) providing a plurality of adiabatic reactors, which include a catalyst bed for dehydrating 2,3-butanediol, without a heat transfer medium, and are connected in series; b) introducing a stream including 2,3-butanediol at a temperature ranging from 200° C. to 400° C. into a first adiabatic reactor among the plurality of adiabatic reactors; c) dehydrating the 2,3-butanediol so as to be converted into 1,3-butadiene and methyl ethyl ketone and discharging a product stream including 1,3-butadiene and methyl ethyl ketone; d) heating the discharged product stream to 200° C. to 400° C.; and e) introducing the heated product stream into a second adiabatic reactor so that 2,3-butanediol is further dehydrated and converted into 1,3-butadiene and methyl ethyl ketone and then discharging the product stream including 1,3-butadiene and methyl ethyl ketone.
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Paragraph 0080; 0081; 0083
(2018/01/04)
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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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- 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 00191-00194
(2016/01/25)
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- Influence of basicity on 1,3-butadiene formation from catalytic 2,3-butanediol dehydration over γ-alumina
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The direct catalytic conversion of 2,3-butanediol (BDO) to 1,3-butadiene (BD) was studied over two commercial forms of alumina (denoted as F200 and SCFa) at temperatures between 240?°C and 450?°C. Even though these two catalysts are both high surface area forms of γ-alumina, they gave remarkably different results, with SCFa giving higher BD selectivities at all experimental conditions. The difference is attributed to the higher surface area of F200, which means a greater number of acid sites that can convert BDO to methyl ethyl ketone (MEK). NH3 and CO2-TPD results supported this conclusion by showing that the two forms of alumina had different acid/base properties. Experimental results also showed that BD selectivity was improved by increasing temperature, increasing residence time and co-feeding water. The residence time study combined with density functional theory (DFT) calculations proved that 3-buten-2-ol (3B2OL) is an important intermediate in the conversion of BDO to BD. BD selectivity decreases over sodium modified alumina SCFa. It is hypothesized that on sodium-modified alumina, 3B2OL is dehydrogenated to form methyl vinyl ketone (MVK) as opposed to dehydration to BD. Basic sites catalyzed the retro-aldol condensation of MVK, which produces acetone and formaldehyde via cleavage of the C[dbnd]C bond. This is in agreement with DFT calculations showing that the proposed pathway for acetone formation is more energetically favored on Na-modified γ-Al2O3 (1?1?0) surface compared to the pristine (1?1?0) surface.
- Zeng, Fan,Tenn, William J.,Aki, Sudhir N.V.K.,Xu, Jiayi,Liu, Bin,Hohn, Keith L.
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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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- PROCESS FOR THE PRODUCTION OF DIENES
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Process for the production of a diene, preferably a conjugated diene, more preferably 1,3-butadiene, comprising the dehydration of at least one alkenol in the presence of at least one catalytic material comprising at least one acid catalyst based on silica (SiO2) and alumina (AI2O3), preferably a silica-alumina (SiO2-AI2O3), said catalyst having a content of alumina (AI2O3) lower than or equal to 12% by weight, preferably ranging from 0.1% by weight to 10% by weight, with respect to the total weight of the catalyst. Preferably, said alkenol can be obtained directly from biosynthesis processes, or through the catalytic dehydration of at least one diol, preferably a butanediol, more preferably 1, 3-butanediol, even more preferably bio-1,3-butanediol, deriving from biosynthesis processes. Preferably, said 1,3-butadiene is bio-1,3-butadiene.
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Page/Page column 43; 44
(2016/09/22)
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- Conversion of 2,3-Butanediol over Phosphate Catalysts
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2,3-Butanediol (BDO) is an excellent feedstock for expanding the network of bio-based chemicals through catalytic technologies. The dehydration of BDO provides an alternative green route to important chemicals such as methyl ethyl ketone (MEK) and 1,3-butadiene (BD). In this contribution, we report on the catalytic performance of boron (BP), aluminum (AlP), titanium (TiP), zirconium (ZrP), and niobium (NbP) phosphates in BDO dehydration. The kinetic study points to three reaction pathways operating over phosphate catalysts, leading to MEK, 2-methyl-propanal (MP), and BD via intermediate 3-butene-2-ol (3B2OL) formation. The major reaction pathway is shown to involve pinacol rearrangement to MEK. The reactivity of phosphates is found to increase in the order: BPTiPZrP=NbPAlP. The best catalytic performance is achieved over AlP, which shows the highest selectivity towards MEK (78 %) at 100 % 2,3-butanediol conversion.
- Nikitina, Maria A.,Ivanova, Irina I.
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p. 1346 - 1353
(2016/04/20)
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- 2,3-Butanediol dehydration catalyzed by silica-supported sodium phosphates
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Catalytic gas phase dehydration of 2,3 butanediol (BDO) was studied in the fixed bed reactor over silica-supported sodium phosphates for a wide range of Na/P ratios (Na/P = 0-3) and variable content of phosphates. Major products were 1,3-butadiene (BD) and methyl ethyl ketone (MEK) for long contact times. 3-Buten-2-ol (3B2OL) and MEK are major products for the short contact times. Achieved yields of elimination products (BD + 3B2OL) were over 60% per pass at Na/P = 1.8-1.9 which is the optimum combination of acidic and basic components for the long term production of BD or 3B2OL from BDO. Minor products detected at short contact times (2,3-epoxybutane, 2,3-butanedione and acetoin) imply that hydrogen transfer and dehydrative epoxidation are minor pathways. Mass transport limitations are more apparent for BDO → 3B2OL → BD route (elimination) than for BDO → MEK route (rearrangement). This leads to the lower selectivity of elimination products at long contact time and/or insufficient flow rate of the carrier gas. 2-butanol dehydration using the same catalysts shows considerable selectivity to 1-butene (1-BT) providing evidence for E1cB elimination mechanism that requires concerted action of acid-base pairs. NH3 and CO2 TPD studies confirmed existence of weak acid and basic sites for the sodium phosphates supported on silica. High affinity adsorption of pyridine (Py) and benzoic acid (BA) shows maximum of acid/base ratio at Na/P~1.5-2. According to XRD and 31P MAS NMR data the catalysts providing the best performance are composed of pyrophosphates and tripolyphosphates finely dispersed on the surface of silica. XPS shows considerable migration of surface sodium cations into the bulk when Na/P ratio exceeds 1.4.
- Kim, Wooyoung,Shin, Wookyun,Lee, Kyoung Jun,Song, Hyohak,Kim, Hyung Soon,Seung, Doyoung,Filimonov, Igor N.
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p. 156 - 167
(2016/01/09)
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- Method for producing 1,3-butadiene and/or 3-buten-2-ol
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Disclosed is a method for producing 1,3-butadiene and/or 3-buten-2-ol from 2,3-butanediol with high selectivity without requiring the use of a radioactive substance. The method for producing 1,3-butadiene and/or 3-buten-2-ol comprises a step of dehydrating 2,3-butanediol in the presence of scandium oxide. The method enables the production of 1,3-butadiene and/or 3-buten-2-ol from 2,3-butanediol with high selectivity without requiring the use of a radioactive substance.
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Paragraph 0070; 0071; 0072; 0073; 0074; 0075; 0076
(2017/01/31)
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- Iridium-catalyzed enantioselective allylation of silyl enol ethers derived from ketones and α,β-unsaturated ketones
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The unified Ir-catalyzed enantioselective allylic substitution reactions of silyl enol ethers derived from ketones and α,β-unsaturated ketones with branched, racemic allylic alcohols are described. This transformation is catalyzed by the Carreira system and proceeds without fluoride, and with high ee and b:l ratio. The synthetic utility of this method was illustrated by the concise enantioselective total synthesis of marine natural products calyxolane A, B and by the assignment of the absolute configuration of calyxolane A.
- Liang, Xiao,Wei, Kun,Yang, Yu-Rong
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supporting information
p. 17471 - 17474
(2015/12/09)
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- METHOD FOR PRODUCING 3-BUTENE-2-OL AND 1,3-BUTADIENE
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PROBLEM TO BE SOLVED: To provide a method for producing 3-butene-2-ol and 1,3-butadiene from 2, 3-butanediol at a high selectivity without using radioactive substances. SOLUTION: Provided is a method for producing 3-butene-2-ol in which 2, 3-butanediol is dewatered using at least one kind selected from a group consisting of zirconium oxide, a zirconium oxide-alkali metal compound complex and zirconium-alkaline-earth metallic compound complex as a catalyst. COPYRIGHT: (C)2015,JPOandINPIT
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Paragraph 0066-0071; 0084; 0085
(2018/11/22)
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- METHOD FOR PRODUCING 3-BUTENE-2-OL
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PROBLEM TO BE SOLVED: To provide a method for efficiently producing racemic 3-butene-2-ol having an (S)- or (R)-configuration. SOLUTION: There is provided a method for producing racemic 3-butene-2-ol, wherein an ammonium salt compound represented by the following general formula (1) (wherein, R1, R2 or R3 represents an alkyl group, an aryl group or an aralkyl group; X- represents OH-, HCO3-, CO32-, R4O-, R5CO2-, R6SO3- (R4, R5 or R6 represents an alkyl group, an aryl group or an aralkyl group) and a halide ion; n represents 0.5 when X- is CO32- and n represents 1 when X- is other than CO32-; the carbon atom marked with * is an asymmetric carbon atom) is subjected to Hofmann elimination. COPYRIGHT: (C)2016,JPOandINPIT
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Paragraph 0037; 0038
(2016/11/07)
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- METHOD FOR PRODUCING BUTADIENE AND/OR 3-BUTENE-2-OL
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PROBLEM TO BE SOLVED: To industrially produce butadiene and/or 3-butene-2-ol from 2,3-butanediol at a high selectivity coefficient without using thorium oxide. SOLUTION: In the production method, using the alkali metal salt of phosphoric acid as a catalyst, 2,3-butanediol is dewatered to produce butanediol and/or 3-butene-2-ol. As the alkali metal salt of phosphoric acid, at least one kind selected from the group consisting of K, Rb and Cs or their mixture is used. The 3-butene-2-ol is dewatered in the presence of an acid catalyst to produce butadiene. COPYRIGHT: (C)2015,JPOandINPIT
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Paragraph 0072
(2017/01/02)
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- Gas-phase dehydration of vicinal diols to epoxides: Dehydrative epoxidation over a Cs/SiO2 catalyst
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A novel type of dehydration reaction that produces epoxides from vicinal diols (dehydrative epoxidation) using a basic catalyst is reported. Epoxyethane, 1,2-epoxypropane, and 2,3-epoxybutane were produced from the dehydrative epoxidation of ethylene glycol, 1,2-propanediol, and 2,3-butanediol, respectively. Among a number of tested basic catalysts, the Cs/SiO2 catalyst showed outstanding performance for the dehydrative epoxidation of 2,3-butanediol and is considered to be the most promising catalyst for this type of reaction. In order to identify the superiority of the Cs/SiO2 catalyst and a mechanism of the reaction, structure-activity relationships were studied along with density functional theory (DFT) calculations. The following features are found to be responsible for the excellent activity of the Cs/SiO2 catalyst: i) strong basic sites formed by Cs+, ii) low penetration of Cs+ into SiO2 which permits basic sites to be accessible to the reactant, iii) stable basic sites due to the strong interactions between Cs+ and SiO2 surface, and iv) mildly acidic surface of SiO2 which is advantageous for the elimination to H2O. In addition, the dehydrative epoxidation involves an inversion of chirality (e.g. meso-2,3-butanediol (R,S) to trans-2,3-epoxybutane (R,R or S,S)), which is in agreement with DFT results that the reaction follows a stereospecific SN2-like mechanism.
- Kim, Tae Yong,Baek, Jayeon,Song, Chyan Kyung,Yun, Yang Sik,Park, Dae Sung,Kim, Wooyoung,Han, Jeong Woo,Yi, Jongheop
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- CONVERSION OF 2,3-BUTANEDIOL TO BUTADIENE
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A composition comprising 2,3-butanediol is dehydrated to methyl vinyl carbinol and/or 1,3-butadiene by exposure to a catalyst comprising (a) MxOy wherein M is a rare earth metal, a group IIIA metal, Zr, or a combination thereof, and x and y are based upon an oxidation state of M, or (b) M3a(PO4)b where M3 is a group IA, a group IIA metal, a group IIIA metal, or a combination thereof, and a and b are based upon the oxidation state of M3. Embodiments of the catalyst comprising MxOy may further include M2, wherein M2 is a rare earth metal, a group IIA metal, Zr, Al, or a combination thereof. In some embodiments, 2,3-butanediol is dehydrated to methyl vinyl carbinol and/or 1,3-butadiene by a catalyst comprising MxOy, and the methyl vinyl carbinol is subsequently dehydrated to 1,3-butadiene by exposure to a solid acid catalyst.
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Paragraph 0083
(2015/09/22)
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- Efficient production of 1,3-butadiene in the catalytic dehydration of 2,3-butanediol
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Vapor-phase catalytic dehydration of 2,3-butanediol (2,3-BDO) was investigated over rare earth oxide catalysts and In2O3 at around 400 ° C. In the dehydration of 2,3-BDO over Sc2O3,1,3-butadiene was mainly produced together with butanone, 2-methyl-propanal, 2-methyl-propanol, 3-buten-2-ol, and butene isomers. Sc2O3 calcined at 800°C showed the highest 1,3-butadiene yield of 88.3% at 411 °C in H2 carrier gas flow. Since 3-buten-2-ol is produced selectively from 2,3-BDO over Sc2O3 at a low temperature of 325 °C, 3-buten-2-ol rather than butanone is a probable intermediate from 2,3-BDO to 1,3-butadiene. 3-Buten-2-ol is readily converted into 1,3-butadiene at temperatures lower than 411 °C over Sc2O3 and Al2O3. In addition, double-bed catalysts composed of an upper catalyst bed of Sc2O3 and a lower of Al2O3 successfully converted 2,3-BDO directly into 1,3-butadiene with a stable selectivity higher than 94% at 318°C and 100% conversion of 2,3-BDO.
- Duan, Hailing,Yamada, Yasuhiro,Sato, Satoshi
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p. 163 - 169
(2015/05/05)
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- Efficient production of 1,3-butadiene in the catalytic dehydration of 2,3-butanediol
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Vapor-phase catalytic dehydration of 2,3-butanediol (2,3-BDO) was investigated over rare earth oxide catalysts and In2O3 at around 400°C. In the dehydration of 2,3-BDO over Sc2O3, 1,3-butadiene was mainly produced together with butanone, 2-methyl-propanal, 2-methyl-propanol, 3-buten-2-ol, and butene isomers. Sc2O3 calcined at 800°C showed the highest 1,3-butadiene yield of 88.3% at 411°C in H2 carrier gas flow. Since 3-buten-2-ol is produced selectively from 2,3-BDO over Sc2O3 at a low temperature of 325°C, 3-buten-2-ol rather than butanone is a probable intermediate from 2,3-BDO to 1,3-butadiene. 3-Buten-2-ol is readily converted into 1,3-butadiene at temperatures lower than 411°C over Sc2O3 and Al2O3. In addition, double-bed catalysts composed of an upper catalyst bed of Sc2O3 and a lower of Al2O3 successfully converted 2,3-BDO directly into 1,3-butadiene with a stable selectivity higher than 94% at 318°C and 100% conversion of 2,3-BDO.
- Duan, Hailing,Yamada, Yasuhiro,Sato, Satoshi
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p. 163 - 169
(2015/05/05)
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- Enantioselective synthesis of 3-substituted 1,2-oxazinanes via organocatalytic intramolecular aza-Michael addition
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A highly enantioselective intramolecular 6-exo-trig aza-Michael addition was developed to afford chiral 3-substituted 1,2-oxazinanes in high yields (up to 99% yield) and good enantioselectivities (up to 98/2 er). These reactions were enabled by a quinine-derived primary-tertiary diamine as a catalyst and pentafluoropropionic acid (PFP) as a co-catalyst.
- Cheng, Shuanghua,Yu, Shouyun
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supporting information
p. 8607 - 8610
(2014/12/10)
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- N-Heterocyclic carbene-catalyzed double acylation of enones with benzils
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Thiazolium carbene-catalyzed reaction of aromatic 1,2-diketones with enones in aprotic solvents gave double acylation products in good yields, whereas hydroacylation products formed by Stetter reaction were not detected at all. These results suggested the generation of aroyloxyenamine species from the 1,2-diketones instead of hydroxyenamines (Breslow intermediates). This journal is
- Takaki, Ken,Ohno, Akira,Hino, Makoto,Shitaoka, Takashi,Komeyama, Kimihiro,Yoshida, Hiroto
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supporting information
p. 12285 - 12288
(2014/12/11)
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- Vapor-phase catalytic dehydration of 2,3-butanediol into 3-buten-2-ol over Sc2O3
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Vapor-phase catalytic dehydration of 2,3-butanediol (2,3-BDO) was investigated over rare earth oxide (REO) catalysts as well as In2O3. In the dehydration of 2,3-BDO, 3-buten-2-ol (3B2OL) was produced together with 3-hydroxy-2-butanone (3H2BO), butanone (MEK), 2-methylpropanal (IBA), 2-methyl-1-propanol (IBO), etc. Sc2O3 and In2O3 showed hi gher 3B2OL select ivities than other REOs. In particular, Sc2O3 converted 2,3-BDO into 3B2OL with an excellent selectivity of 85.0% at 99.9% conversion.
- Duan, Hailing,Yamada, Yasuhiro,Sato, Satoshi
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p. 1773 - 1775
(2015/02/19)
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- Upgrading of diols by gas-phase dehydrogenation and dehydration reactions on bifunctional Cu-based oxides
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Biomass-derived short-chain polyols can be transformed into valuable oxygenates used as building blocks. The gas phase conversion of a model molecule of 1,3-diols (1,3-butanediol), was studied on bifunctional Cu-Mg, Cu-Al and Cu-Mg-Al mixed oxide catalysts that exhibit surface Cu0 particles and acid-base properties. A series of ZCuMgAl catalysts (Z = 0.3-61.2 wt.% Cu, Mg/Al = 1.5 molar ratio) was prepared by coprecipitation and thoroughly characterized by several techniques such as BET surface area, TPR-N2O chemisorption, XRD and TPD of CO2. The ZCuMgAl catalysts promote the upgrading of diols by a series of dehydrogenation and/or dehydration reactions proceeding at reaction rates that depend on the copper content (Z). The overall activity increases linearly with the amount of surface Cu0 species thereby confirming the participation of metallic sites in the rate-limiting steps. Besides, surface Cu0 sites favor the reaction pathway toward 1,3-butanediol dehydrogenation. Thus, the dehydrogenation/dehydration selectivity ratio increases with Z as a result of the enhanced amount of exposed Cu0 particles. ZCuMgAl catalysts with Z 4 ketones and break the intermediates forming C1-C 3 oxygenates; catalysts with Z > 8 wt.% have higher activity and yield valuable multifunctional C4 oxygenates such as hydroxyketones and, to a lesser extent, unsaturated alcohols and ketones. A strongly basic Cu-Mg catalyst promotes the C-C bond cleavage reaction giving short carbon chain oxygenates at low rates; an acidic Cu-Al catalyst converts the diol into C 4 saturated ketones and olefins. the Partner Organisations 2014.
- Torresi,Diez,Luggren,Di Cosimo
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p. 3203 - 3213
(2014/08/18)
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- From the lindlar catalyst to supported ligand-modified palladium nanoparticles: Selectivity patterns and accessibility constraints in the continuous-flow three-phase hydrogenation of acetylenic compounds
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Site modification and isolation through selective poisoning comprise an effective strategy to enhance the selectivity of palladium catalysts in the partial hydrogenation of triple bonds in acetylenic compounds. The recent emergence of supported hybrid materials matching the stereo- and chemoselectivity of the classical Lindlar catalyst holds promise to revolutionize palladium-catalyzed hydrogenations, and will benefit from an in-depth understanding of these new materials. In this work, we compare the performance of bare, lead-poisoned, and ligand-modified palladium catalysts in the hydrogenation of diverse alkynes. Catalytic tests, conducted in a continuous-flow three-phase reactor, coupled with theoretical calculations and characterization methods, enable elucidation of the structural origins of the observed selectivity patterns. Distinctions in the catalytic performance are correlated with the relative accessibility of the active site to the organic substrate, and with the adsorption configuration and strength, depending on the ensemble size and surface potentials. This explains the role of the ligand in the colloidally prepared catalysts in promoting superior performance in the hydrogenation of terminal and internal alkynes, and short-chain alkynols. In contrast, the greater accessibility of the active surface of the Pd-Pb alloy and the absence of polar groups are shown to be favorable in the conversion of alkynes containing long aliphatic chains and/or ketone groups. These findings provide detailed insights for the advanced design of supported nanostructured catalysts. Hybrid nanocatalysts: The classical Lindlar and the newly developed NanoSelectTM catalysts are confronted in the semi-hydrogenation of alkynes (see figure). Systematic testing under continuous-flow three-phase conditions, coupled with detailed characterization analyses and molecular simulations, enable the understanding of the structure of the catalysts and the associated activity and selectivity patterns for a wide range of acetylenic compounds.
- Vile, Gianvito,Almora-Barrios, Neyvis,Mitchell, Sharon,Lopez, Nuria,Perez-Ramirez, Javier
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p. 5926 - 5937
(2014/05/20)
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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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- One-pot reductive sulfenylation and thiocyanation of carbonyl compounds in ionic liquid media
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The first example of an efficient one-pot reductive sulfenylation and thiocyanation of carbonyl compounds in environmentally benign ionic liquid (IL) media is reported. The process involves reduction of carbonyl compounds with NaBH4 in the IL [bmim]BF4 followed by I2-catalyzed reaction of the resulting alcohols with aromatic/aliphatic thiols or ammonium thiocyanate in the same vessel to afford sulfides or thiocyanates, respectively, in excellent yields (78-93%). Notably, the protocol precludes the necessity to prepare and isolate the intermediate alcohols in a separate step as they are formed in situ, and the IL used can be recycled easily for further use without any loss of efficiency. Copyright
- Yadav, Lal Dhar S.,Garima,Kapoor, Ritu
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experimental part
p. 100 - 112
(2011/03/17)
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- Dehydration of 1,3-butanediol over rare earth oxides
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Vapor-phase catalytic dehydration of 1,3-butanediol was investigated over rare earth oxides (REOs) calcined at different temperatures. In the dehydration of 1,3-butanediol over REOs such as Dy2O3, Ho2O3, Er2O3, Tm2O3, Yb2O3, Lu2O3, and Y2O3, 3-buten-2-ol and 2-buten-1-ol were preferentially produced. REOs exhibited different catalytic activities in the dehydration of 1,3-butanediol depending on their crystal structures. CeO2 showed the highest formation rate with the highest selectivity to the unsaturated alcohols among the REOs. Cubic REOs also selectively produced the unsaturated alcohols: cubic Er2O3, Yb2O3, and Lu2O3 showed high formation rate of the unsaturated alcohols. Since the formation rates of the unsaturated alcohols over Er2O3 and CeO2 were suppressed in CO2 and NH3 carrier gas flows more than in H2 flow, it is probable that the acid-base sites play a major role of the formation of the unsaturated alcohols.
- Gotoh, Hiroshi,Yamada, Yasuhiro,Sato, Satoshi
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scheme or table
p. 92 - 98
(2010/08/06)
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- H-bonding as a control element in stereoselective Ru-catalyzed olefin metathesis
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(Chemical Equation Presented) H-bonding interactions have been exploitedextensively in the design of catalysts for stereoselective synthesis bu t have rarely been utilized in the development of metal-catalyzed processes. Studies described herein demonstrate that intramolecular H-bonding interactions can significantly increase the rate and levels of stereochemical control in Ru-catalyzed olefin metathesis reactions. The utility of H-bonding in catalytic olefin metathesis is elucidated through development of exceptionally facile and highly diastereoselective ring-opening/cross-metathesis (DROCM) reactions, involving achiral Ru catalysts and enantiomerically enriched allylic alcohols. Transformations proceed to completion readily (>98percent conversion, up to 87percent yield), often within minutes, in the presence of ≤2 mol percent of an achiral catalyst to afford synthetically versatile products of high stereochemical purity (up to >98:2 dr and 11:1 E:Z).
- Hoveyda, Amir H.,Lombardi, Pamela J.,O'Brien, Robert V.,Zhugralin, Adil R.
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supporting information; experimental part
p. 8378 - 8379
(2009/10/23)
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- Enantioselective hydrolysis of 1-arylallyl acetates catalyzed by Candida antarctica lipase
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(R)-1-Arylallyl alcohols were obtained with excellent enantioselectivities via kinetic resolution of the corresponding acetates using immobilized Candida antarctica lipase. The scope and limitations of this reaction were investigated. The best results are obtained using the water/acetonitrile solvent system, and the reaction tolerates a variety of aryl and heteroaryl substituents.
- Kadnikova, Ekaterina N.,Thakor, Vikalp A.
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p. 1053 - 1058
(2008/09/19)
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