cas 6920-22-5, DL-1,2-Hexanediol | Articles data

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A METHOD FOR PREPARING 1,2-HEXANEDIOL
The present invention provides a colourless. A method for producing high purity 1,2 - hexanediol by reacting 1 - hexenes and hydrogen peroxide to produce 1,2 - hexanediol and reacting with a reducing agent and activated carbon to produce colorless, odorless high purity 1,2 - hexanediol. The method for preparing 1,2 - hexanediol according to the present invention greatly improves purity, yield and quality, is simple and economical and industrially useful, and can be mass-produced and can be applied to various industrial fields.
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Paragraph 0040; 0064-0071; 0076

(2021/10/27)

Sterically controlling 2-carboxylated imidazolium salts for one-step efficient hydration of epoxides into 1,2-diols
In order to overcome the disadvantages of excessive water and many byproducts in the conventional process of epoxide hydration into 1,2-diols, 2-carboxylated imidazolium salts were first adopted as efficient catalysts for one-step hydration of epoxides into 1,2-diols. By regulating the cation chain lengths, different steric structures of 2-carboxylated imidazolium salts with chain lengths from C1 to C4 were prepared. The salt with the shortest substituent chain (DMIC) exhibited better thermal stability and catalytic performance for hydration, achieving nearly 100% ethylene oxide (EO) conversion and 100% ethylene glycol (EG) selectivity at 120 °C, 0.5 h with just 5 times molar ratio of H2O to EO. Such a tendency is further confirmed and explained by both XPS analysis and DFT calculations. Compared with other salts with longer chains, DMIC has stronger interaction of CO2?anions and imidazolium cations, exhibiting a lower tendency to release CO2?and form HO-CO2?, which can nucleophilically attack and synergistically activate ring-opening of epoxides with imidazolium cations. The strong huge sterically dynamic structure ring-opening transition state slows down the side reaction, and both cations and anions stabilized the transition state imidazolium-EG-HO-CO2?, both of which could avoid excessive hydration into byproducts, explaining the high 1,2-diol yield. Based on this, the cation-anion synergistic mechanism is then proposed.
Cheng, Weiguo,Dong, Li,Fu, Mengqian,Su, Qian,Tan, Xin,Yao, Xiaoqian,Ying, Ting,Zhang, Suojiang
p. 2992 - 3000
(2021/05/07)

Diol-Ritter Reaction: Regio- And Stereoselective Synthesis of Protected Vicinal Aminoalcohols and Mechanistic Aspects of Diol Monoester Disproportionation
The well-known epoxide-Ritter reaction generally affords oxazolines with poor to average regioselectivity. Herein, a mechanism-based study of the less known diol-Ritter reaction has provided a highly regioselective procedure for the synthesis of 1-vic-amido-2-esters from either terminal epoxides or 1,2-diols via Lewis acid-catalyzed monoesterification. When treated with a stoichiometric Lewis acid catalyst (BF3), these diol monoesters form dioxonium cation intermediates that are ring-opened with nitrile nucleophiles to form nitrilium intermediates, which undergo rapid and irreversible hydration to give the desired amidoesters. Diester byproduct formation is irreversible and appears to occur through disproportionation of diol monoester. With chiral epoxide starting materials, the formation of amidoester occurs with retention of configuration and no apparent erosion of optical purity as determined by single-crystal X-ray analyses and chiral chromatography, respectively. The direct access to chiral vic-amidoesters is especially practical with regard to the synthesis of antibacterial oxazolidinone analogues of the Zyvox antimicrobial family.
Abboud, Khalil A.,Cheng, Kevin,Klosin, Jerzy,Kruper, William J.,Kruper, William R.,Lysenko, Ivan,Ondari, Mark E.,Thomas, Pulikkottil J.
(2021/10/20)

Understanding the mechanism of N coordination on framework Ti of Ti-BEA zeolite and its promoting effect on alkene epoxidation reaction
The function of ammonium salts on the epoxidation performance over Ti-BEA zeolite was investigated in detail. Experiments of alkene epoxidation, side reactions of epoxide and decomposition of H2O2 with or without ammonium salts were designed, and the UV-Vis spectroscopy was employed to analyze the structure of Ti-hydroperoxo species. It is revealed that the ammonia (or amines) dissociated from the ammonium salt would chelate with the linear Ti-η1(OOH) species and form a bridged Ti-η2(OOH)-R species, which is more stable, more weaker in epoxide adsorption and acidity as well. Therefore, side reactions and H2O2 decomposition would be suppressed, and both alkene conversion and epoxide selectivity would be promoted simultaneously. On the other hand, the excessive NH3?H2O (NH3/Ti>1) or NaOH bond with the Ti-η2(OOH)-R species and generate salt-like Ti-η2(OO)-M+ species, resulting in the deactivation of Ti active center. While for ammonium salts, e.g. NH4Cl, the limited dissociation degree along with the acidic environment help the Ti active center to maintain in highly active. In short, this work provides a practical Ti active center tuning method for Ti-BEA zeolite, as well as a thorough understanding of its Ti-hydroperoxo species.
Liang, Xiaohang,Liu, Dan,Luo, Yibin,Peng, Xinxin,Shu, Xingtian,Xia, Changjiu
(2021/07/31)

Chromium-Catalyzed Production of Diols From Olefins
Processes for converting an olefin reactant into a diol compound are disclosed, and these processes include the steps of contacting the olefin reactant and a supported chromium catalyst comprising chromium in a hexavalent oxidation state to reduce at least a portion of the supported chromium catalyst to form a reduced chromium catalyst, and hydrolyzing the reduced chromium catalyst to form a reaction product comprising the diol compound. While being contacted, the olefin reactant and the supported chromium catalyst can be irradiated with a light beam at a wavelength in the UV-visible spectrum. Optionally, these processes can further comprise a step of calcining at least a portion of the reduced chromium catalyst to regenerate the supported chromium catalyst.
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Paragraph 0111

(2021/03/19)

Diethylene Glycol/NaBr Catalyzed CO2 Insertion into Terminal Epoxides: From Batch to Continuous Flow
CO2 insertion reactions on terminal epoxides (styrene oxide, 1,2-epoxyhexane and butyl glycidyl ether) were performed in a binary homogeneous mixture comprising NaBr as the nucleophilic catalyst and diethylene glycol (DEG) as both solvent and catalyst activator (cation coordinating agent). The reaction protocol was initially studied under batch conditions either in autoclaves and glass reactors: quantitative formation of the cyclic organic carbonate products (COCs) were achieved at T=100 °C and p0(CO2)=1–40 bar. The process was then transferred to continuous-flow (CF) mode. The effects of the reaction parameters (T, p(CO2), catalyst loading, and flow rates) were studied using microfluidic reactors of capacities variable from 7.85 ? 10?2 to 0.157 cm3. Albeit the CF reaction took place at T=220 °C and 120 bar, CF improved the productivity and allowed catalyst recycle through a semi-continuous extraction procedure. For the model case of 1,2-epoxyhexane, the (non-optimized) rate of formation of the corresponding carbonate, 4-butyl-1,3-dioxolan-2-one, was increased up to 27.6 mmol h?1 equiv.?1, a value 2.5 higher than in the batch mode. Moreover, the NaBr/DEG mixture was reusable without loss of performance for at least 4 subsequent CF-tests.
Rigo, Davide,Calmanti, Roberto,Perosa, Alvise,Selva, Maurizio,Fiorani, Giulia
p. 2005 - 2016
(2021/02/27)

A Heterogeneous Pt-ReOx/C Catalyst for Making Renewable Adipates in One Step from Sugar Acids
Renewable adipic acid is a value-added chemical for the production of bioderived nylon. Here, the one-step conversion of mucic acid to adipates was achieved in high yield through deoxydehydration (DODH) and catalytic transfer hydrogenation (CTH) by a bifunctional Pt-ReOx/C heterogeneous catalyst with isopropanol as solvent and reductant. The Pt-ReOx/C catalyst is reusable and was regenerated at least five times. The catalyst exhibits a broad substrate scope of various diols. Spectroscopic studies of Pt-ReOx/C revealed ReVII and Pt0 as the relevant species for DODH and CTH, respectively. Isotope labeling experiments support a monohydride mechanism for CTH over Pt. This work demonstrates a reusable bifunctional catalyst for a one-step valorization of sugar acids to a practical monomer, which opens the door to multifunctional catalysis streamlining valorization of biomass-derived molecules.
Jang, Jun Hee,Ro, Insoo,Christopher, Phillip,Abu-Omar, Mahdi M.
p. 95 - 109
(2021/01/12)

An Amphiphilic (salen)Co Complex – Utilizing Hydrophobic Interactions to Enhance the Efficiency of a Cooperative Catalyst
An amphiphilic (salen)Co(III) complex is presented that accelerates the hydrolytic kinetic resolution (HKR) of epoxides almost 10 times faster than catalysts from commercially available sources. This was achieved by introducing hydrophobic chains that increase the rate of reaction in one of two ways – by enhancing cooperativity under homogeneous conditions, and increasing the interfacial area under biphasic reaction conditions. While numerous strategies have been employed to increase the efficiency of cooperative catalysts, the utilization of hydrophobic interactions is scarce. With the recent upsurge in green chemistry methods that conduct reactions ‘on water’ and at the oil-water interface, the introduction of hydrophobic interactions has potential to become a general strategy for enhancing the catalytic efficiency of cooperative catalytic systems. (Figure presented.).
Solís-Mu?ana, Pablo,Salam, Joanne,Ren, Chloe Z.-J.,Carr, Bronte,Whitten, Andrew E.,Warr, Gregory G.,Chen, Jack L.-Y.
supporting information
p. 3207 - 3213
(2021/06/01)

Well-defined Cp*Co(III)-catalyzed Hydrogenation of Carbonates and Polycarbonates
We herein report the catalytic hydrogenation of carbonates and polycarbonates into their corresponding diols/alcohols using well-defined, air-stable, high-valent cobalt complexes. Several novel Cp*Co(III) complexes bearing N,O-chelation were isolated for the first time and structurally characterized by various spectroscopic techniques including single crystal X-ray crystallography. These novel Co(III) complexes have shown excellent catalytic activity to produce value added diols/alcohols from carbonate and polycarbonates through hydrogenation using molecular hydrogen as sole reductant or iPrOH as transfer hydrogenation source. To demonstrate the developed methodology's practical applicability, we have recycled the bisphenol A monomer from compact disc (CD) through hydrogenation under the established reaction conditions using phosphine-free, earth-abundant, air- and moisture-stable high-valent cobalt catalysts.
Dahiya, Pardeep,Gangwar, Manoj Kumar,Sundararaju, Basker
p. 934 - 939
(2020/12/15)

Dendrimer crown-ether tethered multi-wall carbon nanotubes support methyltrioxorhenium in the selective oxidation of olefins to epoxides
Benzo-15-crown-5 ether supported on multi-wall carbon nanotubes (MWCNTs) by tethered poly(amidoamine) (PAMAM) dendrimers efficiently coordinated methyltrioxorhenium in the selective oxidation of olefins to epoxides. Environmentally friendly hydrogen peroxide was used as a primary oxidant. Up to first and second generation dendrimer aggregates were prepared by applying a divergent PAMAM methodology. FT-IR, XRD and ICP-MS analyses confirmed the effective coordination of methyltrioxorhenium by the benzo-15-crown-5 ether moiety after immobilization on MWCNTs. The novel catalysts converted olefins to the corresponding epoxides in high yield without the use of Lewis base additives, or anhydrous hydrogen peroxide, the catalyst being stable for more than six oxidative runs. In the absence of the PAMAM structure, the synthesis of diols largely prevailed.
Bizzarri, Bruno Mattia,Botta, Lorenzo,Crucianelli, Marcello,Fanelli, Angelica,Ferella, Francesco,Gontrani, Lorenzo,Sadun, Claudia,Saladino, Raffaele
p. 17185 - 17194
(2020/05/18)

The charge-assisted hydrogen-bonded organic framework (CAHOF) self-assembled from the conjugated acid of tetrakis(4-aminophenyl)methane and 2,6-naphthalenedisulfonate as a new class of recyclable Br?nsted acid catalysts
The acid–base neutralization reaction of commercially available disodium 2,6-naphthalenedisulfonate (NDS, 2 equivalents) and the tetrahydrochloride salt of tetrakis(4-aminophenyl)methane (TAPM, 1 equivalent) in water gave a novel three-dimensional charge-assisted hydrogen-bonded framework (CAHOF, F-1). The framework F-1 was characterized by X-ray diffraction, TGA, elemental analysis, and 1H NMR spectroscopy. The framework was supported by hydrogen bonds between the sulfonate anions and the ammonium cations of NDS and protonated TAPM moieties, respectively. The CAHOF material functioned as a new type of catalytically active Br?nsted acid in a series of reactions, including the ring opening of epoxides by water and alcohols. A Diels–Alder reaction between cyclopentadiene and methyl vinyl ketone was also catalyzed by F-1 in heptane. Depending on the polarity of the solvent mixture, the CAHOF F-1 could function as a purely heterogeneous catalyst or partly dissociate, providing some dissolved F-1 as the real catalyst. In all cases, the catalyst could easily be recovered and recycled.
Belokon, Yuri N.,Dmitrienko, Artem O.,Gak, Alexander S.,Gerasimov, Igor S.,Kuznetsova, Svetlana A.,Larionov, Vladimir A.,Li, Han,Medvedev, Michael G.,Nelyubina, Yulia V.,North, Michael,Saghyan, Ashot S.,Smol'yakov, Alexander F.,Zhereb, Vladimir P.
supporting information
p. 1124 - 1134
(2020/07/10)

The formyloxyl radical: Electrophilicity, C-H bond activation and anti-Markovnikov selectivity in the oxidation of aliphatic alkenes
In the past the formyloxyl radical, HC(O)O, had only been rarely experimentally observed, and those studies were theoretical-spectroscopic in the context of electronic structure. The absence of a convenient method for the preparation of the formyloxyl radical has precluded investigations into its reactivity towards organic substrates. Very recently, we discovered that HC(O)O is formed in the anodic electrochemical oxidation of formic acid/lithium formate. Using a [CoIIIW12O40]5- polyanion catalyst, this led to the formation of phenyl formate from benzene. Here, we present our studies into the reactivity of electrochemically in situ generated HC(O)O with organic substrates. Reactions with benzene and a selection of substituted derivatives showed that HC(O)O is mildly electrophilic according to both experimentally and computationally derived Hammett linear free energy relationships. The reactions of HC(O)O with terminal alkenes significantly favor anti-Markovnikov oxidations yielding the corresponding aldehyde as the major product as well as further oxidation products. Analysis of plausible reaction pathways using 1-hexene as a representative substrate favored the likelihood of hydrogen abstraction from the allylic C-H bond forming a hexallyl radical followed by strongly preferred further attack of a second HC(O)O radical at the C1 position. Further oxidation products are surmised to be mostly a result of two consecutive addition reactions of HC(O)O to the CC double bond. An outer-sphere electron transfer between the formyloxyl radical donor and the [CoIIIW12O40]5- polyanion acceptor forming a donor-acceptor [D+-A-] complex is proposed to induce the observed anti-Markovnikov selectivity. Finally, the overall reactivity of HC(O)O towards hydrogen abstraction was evaluated using additional substrates. Alkanes were only slightly reactive, while the reactions of alkylarenes showed that aromatic substitution on the ring competes with C-H bond activation at the benzylic position. C-H bonds with bond dissociation energies (BDE) ≤ 85 kcal mol-1 are easily attacked by HC(O)O and reactivity appears to be significant for C-H bonds with a BDE of up to 90 kcal mol-1. In summary, this research identifies the reactivity of HC(O)O towards radical electrophilic substitution of arenes, anti-Markovnikov type oxidation of terminal alkenes, and indirectly defines the activity of HC(O)O towards C-H bond activation.
Iron, Mark A.,Khenkin, Alexander M.,Neumann, Ronny,Somekh, Miriam
p. 11584 - 11591
(2020/11/23)

Hydrogenolysis of Glucose into Propylene Glycol over Pt/SiO2@Mg(OH)2 Catalyst
One-pot selective conversion of glucose is a green approach compared with petroleum-based processes to produce 1,2-propylene glycol (1,2-PG), but its realization is hindered by various side reactions. Here we demonstrate a feasible strategy of Pt/SiO2@Mg(OH)2 core-shell catalyst to achieve the 1,2-PG yield of 53.8 % by a three-pronged promotion, including enhancement of the glucose-fructose isomerization and retro-aldol condensation (RAC), as well as re-conversion of by-product hexitol into 1,2-PG. We realized the in situ synthesis of the core-shell structure using a self-existent Mg(OH)2 base instead of an extraneous base in the hydrothermal process and it achieved a stable performance during reuse by protecting Pt from leaching.
Gu, Minyan,Shen, Zheng,Zhang, Wei,Xia, Meng,Jiang, Jikang,Dong, Wenjie,Zhou, Xuefei,Zhang, Yalei
p. 3447 - 3452
(2020/05/18)

PNN tridentate ligand, ruthenium complex, and preparation method and application of ruthenium complex
The invention discloses a PNN tridentate ligand, a ruthenium complex, and a preparation method and an application of the ruthenium complex. The structure of the ruthenium complex is represented by formula I, and the ruthenium complex has good catalytic activity in a reaction of converting cyclic carbonate into methanol and a reaction of hydrogenating and degrading polyester and polycarbonate. In addition, the PNN tridentate ligand and the ruthenium complex of the PNN tridentate ligand are good in stability, and the synthesis process is simple.
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Paragraph 0187-0192

(2020/06/04)

1. 2 - O-alcohol synthetic method of the compound (by machine translation)
The invention relates to a 1, 2 - O-alcohol synthetic method of the compound. The synthetic method comprises the following steps: (1) in order to at the end of the olefin as raw materials, potassium persulfate compound salt as the oxidizing agent, inorganic salt as catalyst, water and ketone organic solvent as a reaction solvent, for 30 - 100 °C reaction; (2) reaction after the end of the, 0 - 40 °C adding inorganic alkali, the pH for the reaction system 10 - 14; (3) for 30 - 100 °C continue to reaction, after the end of the reaction, separation and purification, be 1, 2 - O-alcohol compound. The method for synthesis of mild reaction system, the raw material is cheap, the oxidizing agent is environment-friendly, good reaction selectivity, high conversion rate. (by machine translation)
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Paragraph 0028; 0029; 0041; 0042; 0043; 0044

(2019/03/17)

Topotactic Conversion of Alkali-Treated Intergrown Germanosilicate CIT-13 into Single-Crystalline ECNU-21 Zeolite as Shape-Selective Catalyst for Ethylene Oxide Hydration
The conversion of the alkali-treated intergrowth germanosilicate CIT-13 into the single-crystalline high-silica ECNU-21 (named after East China Normal University) zeolite, with a novel topology and a highly crystalline zeolite framework, has been realized through a creative top-down strategy involving a mild alkaline-induced multistep process consisting of structural degradation and reconstruction. Instead of acid treatment, hydrolysis in aqueous ammonia solution not only readily cleaved the chemically weak Ge(Si)?O?Ge bonds located within the interlayer double four ring (D4R) units of CIT-13, but also cleaved the metastable Si?O?Si bonds therein. This led to extensive removal of the D4R units, and also generated silanol groups on adjacent silica-rich layers, which then condensed to form a novel daughter structure upon calcination. Individual oxygen bridges in the reassembled ECNU-21 replaced the germanium-rich D4R units in CIT-13, thereby eliminating the original intergrowth phenomenon along the b axis. With an ordered crystalline structure of 10-ring (R) channels as well as suitable germanium-related Lewis acid sites, ECNU-21 serves as a stable solid Lewis acid catalyst for the shape-selective hydration of ethylene oxide (EO) to ethylene glycol (EG) at greatly reduced H2O/EO ratios and reaction temperature in comparison with the noncatalytic industrial process.
Liu, Xue,Mao, Wenting,Jiang, Jingang,Lu, Xinqing,Peng, Mingming,Xu, Hao,Han, Lu,Che, Shun-ai,Wu, Peng
p. 4520 - 4529
(2019/03/07)

Transfer hydrogenation of cyclic carbonates and polycarbonate to methanol and diols by iron pincer catalysts
Herein, we report the first example on the use of an earth-abundant metal complex as the catalyst for the transfer hydrogenation of cyclic carbonates to methanol and diols. The advantage of this method is the use of isopropanol as the hydrogen source, thus avoiding the handling of flammable hydrogen under high pressure. The reaction offers an indirect route for the reduction of CO2 to methanol. In addition, poly(propylene carbonate) was converted to methanol and propylene glycol. This methodology can be considered as an attractive opportunity for the chemical recycling of polycarbonates.
Liu, Xin,De Vries, Johannes G.,Werner, Thomas
p. 5248 - 5255
(2019/10/11)

Aromatic Donor-Acceptor Interaction-Based Co(III)-salen Self-Assemblies and Their Applications in Asymmetric Ring Opening of Epoxides
Aromatic donor-acceptor interaction as the driving force to assemble cooperative catalysts is described. Pyrene/naphthalenediimide functionalized Co(III)-salen complexes self-assembled into bimetallic catalysts through aromatic donor-acceptor interactions and showed high catalytic activity and selectivity in the asymmetric ring opening of various epoxides. Control experiments, nuclear magnetic resonance (NMR) spectroscopy titrations, mass spectrometry measurement, and X-ray crystal structure analysis confirmed that the catalysts assembled based on the aromatic donor-acceptor interaction, which can be a valuable noncovalent interaction in supramolecular catalyst development.
Liang, Jian,Soucie, Luke N.,Blechschmidt, Daniel R.,Yoder, Aaron,Gustafson, Addie,Liu, Yu
supporting information
p. 513 - 518
(2019/01/14)

Post-modified porphyrin imine gels with improved chemical stability and efficient heterogeneous activity in CO2 transformation
Efficient heterogeneous gel catalysts have been developed based on dynamic covalent chemistry and post-modification methods for the chemical fixation of CO2. Various porphyrin-based imine gels are synthesized and subsequent reduction of imine bonds and metallation with various metal centers yields gel catalysts. The gels are characterized by a number of techniques including SEM, TEM, EDX, FT-IR, CP/MAS 13C NMR, and XPS. The resulting gels not only have network structures including micro-, meso- and macropores, but also show improved chemical stability and strong interactions between CO2 and pore channels. The gel catalysts show good catalytic activity towards the cycloaddition of epoxides with CO2 to cyclic carbonates using wet gels. Post-modified gel catalysts with a Zn(ii) center (ZnTAPP-Go-r) show a high product yield and high stability with recyclability over 5 cycles.
Liao, Peisen,Cai, Guangmei,Shi, Jianying,Zhang, Jianyong
p. 10017 - 10024
(2019/07/04)

Straightforward synthesis of MTW-type magnesium silicalite for CO2 fixation with epoxides under mild conditions
Aluminum-free magnesium silicalite with MTW topology (Mg-Si-ZSM-12) was fabricated via a straightforward hydrothermal synthesis route involving an initial acid co-hydrolysis step. Mg incorporation endowed superior basic properties to the MTW framework, as illustrated by CO2 sorption and temperature programmed desorption plus the activity in a typical basic reaction, Knoevenagel condensation. Mg-Si-ZSM-12 catalyzed the coupling of atmospheric CO2 with epoxides and led to the efficient production of cyclic carbonates with high yield and selectivity at relatively low temperature (down to 60 °C). The present strategy afforded a zeolitic solid base with regular 12-membered ring microporous channels that has potential application in CO2 fixation.
Wen, Haimeng,Xie, Jingyan,Zhou, Yang,Zhou, Yu,Wang, Jun
p. 5725 - 5735
(2019/10/23)

Bifunctional organocatalysts for the conversion of CO2, epoxides and aryl amines to 3-aryl-2-oxazolidinones
A route to synthesize 3-aryl-2-oxazolidinones is developed, which is achieved through a three component reaction between CO2, aryl amines, and epoxides with a binary organocatalytic system composed of organocatalysts and DBU (1,8-diazabicyclo[5.4.0]undec-7-ene). The method allows wide scopes of epoxide and aryl amine substrates with various functional groups under mild reaction conditions. The control experiments indicate that a cyclic carbonate is formed via cycloaddition of epoxides with CO2, which further reacts with the β-amino alcohol originating from epoxides and aryl amines, resulting in the formation of 3-aryl-2-oxazolidinones finally.
Xie, Ya-Fei,Guo, Cheng,Shi, Lei,Peng, Bang-Hua,Liu, Ning
supporting information
p. 3497 - 3506
(2019/04/14)

A catalytic oxidation of 1 - hexene process for preparing 1, 2 - hexane diol (by machine translation)
The invention discloses a catalytic oxidation 1 - hexene process for preparing 1, 2 - hexane diol, the technical features are: formic acid is used as the reaction medium, hydrogen peroxide as the oxidizing agent, in-situ received oxidation formic acid, in the catalyst MVO2 Dipic under the action of the 1 - hexene oxide epoxy compound, after hydrolysis, separation and purification to obtain the 1, 2 - hexanediol. The method of the invention high catalytic efficiency, mild reaction conditions, 1, 2 - hexanediol yield of 85% or more, the purity is greater than 99%. (by machine translation)
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Paragraph 0023-0053

(2018/05/01)

Raw and waste plant materials as sources of fungi with epoxide hydrolase activity. Application to the kinetic resolution of aryl and alkyl glycidyl ethers
The by-products of olive oil production can be used as sources of microbial strains. Penicillium sp., Aspergillus terreus, Penicillium aurantiogriseum, Aspergillus tubingensis and Aspergillus niger were selected on the basis of their epoxide-hydrolyzing activity towards racemic rac-glycidyl phenyl ether. We studied the effect on enzymatic activity of adding styrene oxide to the growth medium. It induced the biosynthesis of epoxide hydrolases and reduced cell growth. The resolution capacity of the five fungi was tested on rac-glycidyl phenyl ether, rac-benzyl glycidyl ether, rac-1,2-epoxyhexane and rac-1,2-epoxyoctane. The resolution of rac-glycidyl phenyl ether by A. niger, rac-benzyl glycidyl ether by P. aurantiogriseum and A. terreus, rac-1,2-epoxyhexane by A. tubingensis and rac-1,2-epoxyoctane by A. terreus provided (S)-3-phenoxy-1,2-propanediol (45.1% yield, 51.4% ee), (R)-3-benzyloxy-1,2-propanediol (40.8% yield, 43.3% ee), (S)-3-benzyloxy-1,2-propanediol (45.4% yield, 45.6% ee), (R)-1,2-hexanediol (70.4% yield, 24.4% ee) and (R)-1,2-octanediol (21.4% yield, 27.5% ee), respectively. The (R)-enantiopreference of the epoxide hydrolases from P. aurantiogriseum is unprecedented.
Dolcet, Marta,Torres, Mercè,Canela-Garayoa, Ramon
p. 78 - 88
(2017/09/30)

Hydrogenation of CO2-Derived Carbonates and Polycarbonates to Methanol and Diols by Metal–Ligand Cooperative Manganese Catalysis
The first base-metal-catalysed hydrogenation of CO2-derived carbonates to alcohols is presented. The reaction proceeds under mild conditions in the presence of a well-defined manganese complex with a loading as low as 0.25 mol %. The non-precious-metal homogenous catalytic system provides an indirect route for the conversion of CO2 into methanol with the co-production of value-added (vicinal) diols in yields of up to 99 %. Experimental and computational studies indicate a metal–ligand cooperative catalysis mechanism.
Zubar, Viktoriia,Lebedev, Yury,Azofra, Luis Miguel,Cavallo, Luigi,El-Sepelgy, Osama,Rueping, Magnus
supporting information
p. 13439 - 13443
(2018/09/21)

Gas-liquid pipeline type preparation method of 1,2-hexanediol
The invention relates to a gas-liquid pipeline type preparation method of 1,2-hexanediol. The method is technically characterized by comprising the following steps: by adopting a gas-liquid pipeline type reactor, performing an epoxidation reaction in an anhydrous organic solvent by taking 1-hexene as a raw material and organic acid peroxide as an oxidizing agent; adding alkali to generate a prilezhayev ring opening reaction to obtain a crude product of 1,2-hexanediol; adding acid to regulate to neutrality; and performing extraction, drying and rectification to obtain 1,2-hexanediol with purity of over 99.0%. The method provided by the invention has the advantages of high reaction efficiency, high yield, good product quality, small floor area, low cost, simplicity in aftertreatment operation, low environmental pollution and high safety of reaction operation and facilitates industrialization.
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Paragraph 0012

(2017/02/02)

Enhanced solvent-free selective oxidation of cyclohexene to 1,2-cyclohexanediol by polyaniline@halloysite nanotubes
One-dimensional polyaniline@halloysite (PANI@HA) nanotubes with enhanced selective oxidation activity of cyclohexene are fabricated by employing aniline (ANI) chemical polymerization on halloysite nanotubes in situ. By facilely controlling the doping acid, acidity, and ANI/HA weight ratio during the fabrication, PANI with a controllable doping degree, redox state, and content is grown on halloysite nanotubes. The cyclohexene selective oxidation result shows that PANI@HA nanotubes are effective catalysts in a solvent-free reaction system with H2O2 as the oxidant, and their catalytic activity relies on the doping acid, acidity, and ANI/HA weight ratio in the fabrication. PANI@HA synthesized with HCl as a doping acid to condition the acidity at 1 M and 2.04 ANI/HA weight ratio (PANI@HA/1 M/2.04-HCl) demonstrates highest catalytic activity (98.17% conversion and 99.50% selectivity to 1,2-cyclohexanediol). The cyclohexene selective catalytic activity matches well with the PANI doping degree in PANI@HA. In addition, the optimal reaction condition is 20 mg catalyst, 2.5 mL H2O2, 70 °C, and 24 h. Furthermore, PANI@HA/1 M/2.04-HCl exhibits superior dihydroxylation activity toward 2,3-dimethyl-2-butene and cycling performance with 99.11% conversion and 96.92% selectivity to 1,2-cyclohexanediol after five cycles. The CV of PANI@HA indicates that the cyclohexene selective oxidation is attributed to a reversible redox reaction of PANI in PANI@HA for catalytic decomposition of H2O2.
Zhou, Tianzhu,Zhao, Yue,Han, Wenmei,Xie, Huazhong,Li, Cuiping,Yuan, Mingquan
p. 18230 - 18241
(2017/09/08)

Cooperative Activation of Cobalt–Salen Complexes for Epoxide Hydration Promoted on Flexible Porous Organic Frameworks
Developing solid catalysts with multiple active sites working cooperatively is desirable for efficient chemical transformations. However, most solid catalysts are rigid and impede the cooperation between their spatially isolated active sites. Two flexible porous organic frameworks (POFs) with integrated Co(salen) as active sites have been successfully synthesized for mimicking the cooperative modes of enzymes. The POFs exhibit second-order rate dependence on Co(salen) concentration in the network and afford much higher TOF (3300 versus 2670 h?1) than the homogeneous counterpart in the hydration of propylene epoxide. POFs with a flexible network thus not only facilitate but also enhance the cooperation of nearby Co(salen). Moreover, POFs could catalyze oversized substrates, have a wide substrate scope, and exhibit high stability.
Zhong, Mingmei,Li, He,Chen, Jian,Tao, Lin,Li, Can,Yang, Qihua
supporting information
p. 11504 - 11508
(2017/08/30)

Conversion of Carbon Dioxide into Oxazolidinones Mediated by Quaternary Ammonium Salts and DBU
A straightforward method to construct oxazolidinones through a three-component reaction involving CO2, epoxides, and amines promoted by a combination of Bu4NI and 1,8-diazabicyclo[5.4.0]undec-7-ene was developed. A wide range of aromatic and aliphatic amines and monosubstituted epoxides were converted into 3,5-disubstituted-2-oxazolidines in up to 95 % yield. This metal-free and easily available catalytic system was applicable to a broad range of substrates, including conventionally challenging ones such as aliphatic epoxides, at atmospheric pressure. Preliminary mechanistic studies suggested a reaction pathway involving β-amino alcohols.
Lv, Min,Wang, Peng,Yuan, Dan,Yao, Yingming
p. 4451 - 4455
(2017/12/26)

Metal nanoparticles supported on WO3 nanosheets for highly selective hydrogenolysis of cellulose to ethylene glycol
Although the conversion of cellulose to polyols is currently well-developed, the production of the considerably valuable ethylene glycol (EG) is still challenging. Reactions have long relied on the design of suitable catalysts to obtain a high selectivity and yield of EG. Herein, using well-shaped rectangular tungsten trioxide nanosheets as the substrate, we investigated the catalytic performances of various metal supported catalysts for the convertion of cellulose to EG. Results show that Ru/WO3 is more favorable for EG production, with the highest EG yield of 76.3% over the 1% Ru/WO3 nanosheet catalyst. Our characterizations and activity tests suggest that the embedding of Ru nanoparticles onto the WO3 nanosheets produces more W5+ active sites under the same reduction conditions (NaBH4 or H2), which act as Lewis base sites to promote the glucose retro-aldol condensation reaction. Moreover, the Ru/WO3 catalyst holds a portion of Ru in the form of amorphous RuOxδ+ phases, which could further increase the H+ released into an aqueous solution for cellulose hydrogenolysis. A possible catalytic mechanism for this hydrogenolysis process is accordingly proposed.
Li, Naixu,Zheng, Yu,Wei, Lingfei,Teng, Hongcheng,Zhou, Jiancheng
p. 682 - 691
(2017/02/26)

Cp2TiCl2-catalyzed cycloboration of α-olefins with PhBCl2in the synthesis of 2-alkyl(aryl,benzyl)-1-phenylboriranes
A one-pot method for the synthesis of 2-alkyl(aryl, benzyl)-1-phenylboriranes has been developed via the reaction of α-olefins with PhBCl2in the presence of Cp2TiCl2as the catalyst. The method implies the formation of boriranes as the result of transmetalation of titanacyclopropane intermediates generated in the reaction of α-olefins with Cp2TiCl2. Individual 1-phenyl-2-substituted boriranes were isolated and their structures confirmed by NMR spectral methods.
Khusainova, Liliya I.,Khafizova, Leila O.,Tyumkina, Tatyana V.,Ryazanov, Kirill S.,Dzhemilev, Usein M.
p. 12 - 17
(2017/02/05)

Direct conversion of carbohydrates to diol by the combination of niobic acid and a hydrophobic ruthenium catalyst
Tetrahydro-2,5-furandimethanol (THFDM) was obtained directly from a wide variety of carbohydrates by the combination of niobic acid and a hydrophobic ruthenium catalyst. Fructose, glucose, and polysaccharides consisting of fructose or glucose could be converted to THFDM in one-step. The selectivity to THFDM was kept around 60% while the glucose conversion varied from 9% to 49%. The as-synthesized niobic acid was characterized by TEM, N2 adsorption/desorption, XRD, NH3-TPD and FT-IR spectra of adsorpted pyridine. The niobic acid was proved to have medium and strong acid sites with a high Br?nsted/Lewis ratio, which played a great role for keeping high THFDM selectivity using glucose as a substrate.
Duan, Ying,Zhang, Jun,Li, Dongmi,Deng, Dongsheng,Ma, Lu-Fang,Yang, Yanliang
p. 26487 - 26493
(2017/07/07)

Asymmetric Hydrolytic and Aminolytic Kinetic Resolution of Racemic Epoxides using Recyclable Macrocyclic Chiral Cobalt(III) Salen Complexes
New chiral macrocyclic cobalt(III) salen complexes were synthesized and used as catalyst for the asymmetric kinetic resolution (AKR) of terminal epoxides and glycidyl ethers with aromatic/aliphatic amines and water as nucleophiles. This is the first occasion where a Co(III) salen complex demonstrated its ability to catalyze AKR as well as hydrolytic kinetic resolution (HKR) reactions. Excellent enantiomeric excesses of the epoxides, the corresponding amino alcohols and diols (upto 99%) with quantitative yields were achieved by using the chiral Co(III) salen complexes in dichloromethane at room temperature. This protocol was further extended for the synthesis of two important drug molecules, i.e., (S)-propranolol and (R)-naftopidil. The catalytic system was also explored for the synthesis of chirally pure diols and chiral cyclic carbonates using carbon dioxide as a greener renewable C1 source. The catalyst was recycled for upto 5 catalytic cycles with retention of enantioselectivity. (Figure presented.).
Tak, Rajkumar,Kumar, Manish,Menapara, Tusharkumar,Gupta, Naveen,Kureshy, Rukhsana I.,Khan, Noor-ul H.,Suresh
supporting information
p. 3990 - 4001
(2017/11/22)

Influence of the functional groups of multiwalled carbon nanotubes on performance of Ru catalysts in sorbitol hydrogenolysis to glycols
Different functional groups (i.e. [sbnd]NH2, [sbnd]COOH, [sbnd]OH and nitrogen-doping) modified CNTs (denoted as AMCN, CMCN, HMCN and NMCN, respectively) supported ruthenium catalysts (Ru/AMCN, Ru/CMCN, Ru/HMCN and Ru/NMCN) were prepared by incipient wetness impregnation method. They were fully characterized by XRD, TG, Raman, XPS, TPD and TEM to elucidate the relationship between the physical property and their catalytic performance. TEM results shown that Ru particles were well dispersed on the surface for all the samples with the size of 1.48–1.99 nm. The effects of functional groups of carbon nanotubes (CNTs), nitrogen doping and base additive types on activity and selectivity of ethylene glycol (EG) and propylene glycol (1,2-PD) were investigated. In addition, the activity and final products distribution were much influenced by the properties of functional groups on CNTs and the type of metal cation of the base promoters, which probably participated in the reaction for accelerating a retro-aldol reaction for C[sbnd]C cleavage. Among the catalysts, Ru supported on AMCN exhibited the best catalytic activities and glycols selectivities than on MCN, CMCN, HMCN and NMCN.
Guo, Xingcui,Dong, Huihuan,Li, Bin,Dong, Linlin,Mu, Xindong,Chen, Xiufang
p. 79 - 87
(2016/12/09)

Synthesis, Characterization and Catalytic Application of Pyridine-Bridged N-Heterocyclic Carbene–Ruthenium Complexes in the Hydrogenation of Carbonates
A series of bulky pyridine-bridged NHC–Ru complexes have been rationally designed and synthesized; these exhibited very high catalytic activity in the hydrogenation of cyclic and linear carbonates under mild reaction conditions. In the presence of catalytic amounts of a weak base, a broad range of substrates with different ring size and steric bulk were well tolerated, providing methanol and the corresponding diols in excellent yields with a catalyst loading as low as 0.5 mol %.
Chen, Jiangbo,Zhu, Haibo,Chen, Jinjin,Le, Zhang-Gao,Tu, Tao
supporting information
p. 2809 - 2812
(2017/10/23)

Heterometallic Metal-Organic Frameworks That Catalyze Two Different Reactions Sequentially
A series of copper- and alkaline-earth-metal-based multidimensional metal-organic frameworks, {[CuMg(pdc)2(H2O)4]·2H2O}n (1), [CuCa(pdc)2]n (2), [CuSr(pdc)2(H2O)3]n (3), and {[Cuba(pdc)2(H2O)5]·H2O}n (4), where H2Pdc = pyridine-2,5-dicarboxylic acid, were hydrothermally synthesized and characterized. Two different metals act as the active center to catalyze two kinds of reactions, viz., olefin to its epoxide followed by epoxide ring opening to afford the corresponding vicinal diol in a sequential manner.
Saha, Debraj,Hazra, Dipak K.,Maity, Tanmoy,Koner, Subratanath
supporting information
p. 5729 - 5731
(2016/07/06)

Aerobic Acetoxyhydroxylation of Alkenes Co-catalyzed by Organic Nitrite and Palladium
An aerobic acetoxyhydroxylation of alkenes cooperatively catalyzed by organic nitrite and palladium at room temperature using clean and cheap air as the sole oxidant has been developed. Various vicinal diols, diacetoxyalkanes, and dihalogenoalkanes have been synthesized. The gram-scale synthesis has also been approached. Vicinal difluorination and dichlorolation products have also been achieved via this reaction.
Chen, Xian-Min,Ning, Xiao-Shan,Kang, Yan-Biao
supporting information
p. 5368 - 5371
(2016/11/02)

Epoxides hydration on CoIII(salen)-OTs encapsulated in silica nanocages modified with prehydrolyzed TMOS
The silylation for reducing the pore entrance size is crucial for the success encapsulation of molecular catalysts. Herein, we reported the preparation of an efficient solid catalyst for epoxide hydration via encapsulation of CoIII(salen)-OTs in the nanocages of FDU-12 using prehydrolyzed tetramethylorthosilicate (TMOS) as silylation reagent under mild condition. CoIII(salen)-OTs in nanocages could afford TOF of 2760 h-1 in the hydration of propylene epoxide (PO), which is the highest ever reported at low PO/H2O molar ratio. Comparison of the activity of CoIII(salen)-OTs accommodated in nanocages with different microenvironments suggests that CoIII(salen)-OTs in hydrophilic microenvironment was more active than that in hydrophobic microenvironment in the hydration of propylene epoxide. Moreover, studies show that the deactivation rate of CoIII(salen)-OAc is lower than that of CoIII(salen)-OTs in nanocages due to the confinement effect of the nanoreactor.
Zhong, Mingmei,Zhao, Yaopeng,Yang, Qihua,Li, Can
p. 184 - 191
(2016/04/04)

Enhancement of Catalytic Activity in Epoxide Hydration by Increasing the Concentration of Cobalt(III)/Salen in Porous Polymer Catalysts
The rational design of catalytic materials from the reaction characteristics is expected to be a useful strategy to create highly efficient catalysts. Herein, according to a well-established reaction pathway of epoxide hydration catalyzed a dual-molecular system of Co3+/salen in which a high concentration of active sites is favorable to enhance the activity, we provide an alternative way to prepare a highly efficient heterogeneous catalyst with a high concentration of Co3+/salen from the polymerization of vinyl-functionalized salen monomers followed by the loading of Co3+ species (Co3+/POL-salen). Co3+/POL-salen has a hierarchical porosity and an extraordinary hydrothermal stability. Importantly, catalytic tests in epoxide hydration demonstrate that Co3+/POL-salen affords excellent high activities, which are even better than those of the homogeneous version. This phenomenon is related to the very high concentration of Co3+/salen in the catalyst. In addition, this catalyst can be recycled readily because of its excellent hydrothermal stability.
Dai, Zhifeng,Sun, Qi,Chen, Fang,Pan, Shuxiang,Wang, Liang,Meng, Xiangju,Li, Jixue,Xiao, Feng-Shou
p. 812 - 817
(2016/03/05)

Epoxide hydrolysis and alcoholysis reactions over crystalline Mo-V-O oxide
Crystalline Mo-V-O oxides have been used as a catalyst for the hydrolysis and alcoholysis of propylene oxide to diols and ethers, respectively. Relationships between the active crystal facet, the acidity of Mo-V-O catalysts and the activity have been established. Our results indicate that the a-b plane is the active facet for the hydrolysis reaction.
Zhang, Xiaochen,Wang, Min,Zhang, Chaofeng,Lu, Jianmin,Wang, Yehong,Wang, Feng
p. 70842 - 70847
(2016/08/05)

Selective oxidation of olefins with aqueous hydrogen peroxide over phosphomolybdic acid functionalized knitting aryl network polymer
A phosphomolybdic acid (PMA)-based heterogeneous catalyst, denoted as PMA/KAP, was prepared by immobilizing PMA onto a knitting aryl network polymer (KAP) based on triphenylphosphine (PPh3). The catalytic property of PMA/KAP was investigated for the selective oxidation of olefins with aqueous hydrogen peroxide (H2O2) as oxidant. When using ethyl acetate (EAC) as reaction medium, PMA/KAP performs higher activity and selectivity to epoxide for a variety of olefins, and it can be reused for several times without obvious loss of activity. When the reaction was carried out in acetonitrile (AN) medium, deactivation of PMA/KAP catalyst can be observed immediately. A variety of characterization results suggest that the degradation of PMA unit to (PO4[MoO(O2)2]4)3- occurs easily when the PMA/KAP catalyst is operated in H2O2/AN system, while such degradation behavior could be significantly inhibited when the catalyst is used in the system of H2O2/EAC. We proposed that the neighbouring P-containing ligands dispersed in the framework of KAP can produce a steric pocket with low electron density, which can promote the formation of multi-weak coordination interaction between PMA unit and several P ligands. Such multi-weak interaction can inhibit the degradation of PMA to (PO4[MoO(O2)2]4)3-, thus avoiding the leaching of active species from the KAP support, and resulting in the formation of relatively stable heterogeneous PMA supported catalyst for olefin epoxidation with H2O2 in the media of EAC.
Song, Xiaojing,Zhu, Wanchun,Yan, Yan,Gao, Hongcheng,Gao, Wenxiu,Zhang, Wenxiang,Jia, Mingjun
p. 32 - 39
(2016/01/09)

Cation-exchange resin towards low-cost synthesis of high-performance TS-1 zeolites in the presence of alkali-metal ions
Zeolite TS-1 is an important commercial catalyst for green production of oxyfunctionalized chemicals such as alcohols, ketones, epoxides, and oximes. However, the extremely high price greatly restricts its wide applications. In this paper, we developed a new route to synthesize highly active TS-1 zeolites by using low-cost tetrapropylammonium hydroxide (TPAOH) as a starting reagent that contains alkali-metal cations such as Na+ and K+ and is much cheaper than the high-purity TPAOH currently used in reported routes. The key point is the introduction of a cation-exchange resin into the synthetic system to capture the alkali-metal cations via ion exchange between the alkali-metal cations in the synthetic medium and protons in the resin, as well as adjusting the pH value of the TS-1 synthetic system. The present development shows great commercial potential and opens the possibility of preparing cheap TS-1 catalysts by using commercial TPAOH raw materials.
Wang, Jin-Gui,Wang, Yabo,Chen, Hongzhong,Lim, Jiesheng,Tatsumi, Takashi,Zhao, Yanli
p. 15615 - 15621
(2016/02/26)

Selective transition-metal-free vicinal cis-dihydroxylation of saturated hydrocarbons
A transition-metal-free cis-dihydroxylation of saturated hydrocarbons under ambient reaction conditions has been developed. The described approach allows a direct and selective synthesis of vicinal diols. The new reaction thereby proceeds via radical iodination and a sequence of oxidation steps. A broad scope of one-pot dual C(sp3)-H bond functionalization for the selective synthesis of vicinal syn-diols was demonstrated.
Bering, Luis,Antonchick, Andrey P.
p. 452 - 457
(2016/12/30)

PROCESS FOR THE TRANSFORMATION OF LIGNOCELLULOSIC BIOMASS INTO MONO- OR POLY-OXYGENATED MOLECULES
The invention concerns a process for the transformation of lignocellulosic biomass or cellulose into mono- or poly-oxygenated compounds, in which the lignocellulosic biomass or the cellulose is brought into simultaneous contact with a catalytic system comprising a combination of one or more homogeneous catalysts and one or more heterogeneous catalysts, in the same reaction chamber, in the presence of at least one solvent, said solvent being water alone or as a mixture with at least one other solvent, in a reducing atmosphere, and at a temperature in the range 80° C. to 250° C. and at a pressure in the range 0.5 MPa to 20 MPa.
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Paragraph 0122-0126

(2016/05/09)

Osmium on chelate resin: Nonvolatile catalyst for the synthesis of DIOLS from alkenes
Osmium tetraoxide (OsO4) was immobilized on a commercially available chelate resin DIAION CR11 (CR11) just by simply immersing it in a methanol solution of OsO4 at room temperature. The resulting purple solid, 5% Os/CR11, indicated no volatility, and effectively catalyzed the oxidation of various alkenes to the corresponding diols.
Monguchi, Yasunari,Wakayama, Fumika,Takada, Hitoshi,Sawama, Yoshinari,Sajiki, Hironao
supporting information
p. 700 - 704
(2015/03/14)

Oxidation of cyclooctene to suberic acid using perrhenate-containing composite ionic liquids as green catalysts
A series of quaternary ammonium perrhenate/3-hexyl-1-methyl-imidazolium hydrogen sulfate ([Hmim]HSO4) composite ionic liquids has been prepared. For the first time, the composite ionic liquids are used both as catalyst and solvent in oxidation of cyclooctene to suberic acid in the presence of hydrogen peroxide as a green oxidant. It was found that organic perrhenate salts play the important role in improving the selectivity of cyclooctene oxidation to suberic acid. The yield of suberic acid under the mild conditions is from good to high.
Wang,Zhou,Yuan,Fu,Zang
p. 2378 - 2385
(2015/11/24)

First example of borirane synthesis by α-olefins reaction with BCl3·SMe2 Catalyzed with (η5-C5H5)2TiCl2
New method was developed of the synthesis of 2-phenyl(alkyl, benzyl, phenoxy)-1-chloroboriranes via reaction of α-olefins with BCl3·SMe2 catalyzed by Cp2TiCl2. The method is based on the boracyclopropanes (boriranes) formation resulting from transmetallation of titanacyclopropanes arising from the reaction of α-olefins with Cp2TiCl2. The calculations were fulfilled of thermodynamic and activation parameters of possible reaction routes.
Khusainova,Khafizova,Tyumkina,Dzhemilev
p. 1517 - 1523
(2015/12/30)

Hydrophobicity enhancement of Ti-MWW catalyst and its improvement in oxidation activity
The effect of the preparation conditions of the Ti-MWW catalyst on the hydrophobicity of the catalyst and its catalytic activity was investigated. Our findings demonstrated that the condensation of interlayer hydroxyl groups was greatly affected by the preparation conditions, in particular washing conditions of the as-synthesized lamellar precursor of Ti-MWW, then further controlling the final hydrophobicity and oxidation properties. Using organic solvents, especially EAOH, instead of water to wash the wet lamellar precursor would synchronize the interlayer hydroxyl condensation with the decrease of interlayer distance mainly caused by the leaching of piperidine, which was used as structure-directing agent (SDA). After acid-treatment, less SDA was kept in the EAOH washed sample and 3D-MWW with less defects was formed by calcination. Both drying temperature and acid-treatment would also affect the amount of SDA occluded in the interlayer void space of the acid-treated samples and then further affect the final interlayer hydroxyl condensation upon the following calcination. The lower both drying temperature and acid-treatment temperature were favorite to unequal interlayer dehydroxylation to form MCM-56, while higher drying temperature such as 150 C not only caused the anatase phase in the calcined samples but also occluded more SDA molecules in the acid-treated samples which greatly affect the further interlayer hydroxyl condensation upon the calcination. Ti-MWW-OH-100 containing smallest amount of silanols and less defect sites showed the best hydrophobicity and the highest catalytic activity in 1-hexene oxidation.
Zhao, Hong,Yokoi, Toshiyuki,Kondo, Junko N.,Tatsumi, Takashi
p. 156 - 164
(2015/08/04)

Design and synthesis of binuclear Co-salen catalysts for the hydrolytic kinetic resolution of epoxides
Three binuclear Co(III)-salen complexes have been synthesized based on a series of hydrophilic cyclic frameworks with different ring sizes. The catalytic performance of Co-salen complexes have further been evaluated in the hydrolytic kinetic resolution of racemic epoxides. And kinetic studies reveal that the binuclear Co-salen catalysts show a higher reactivity and better enantioselectivity in comparison to monometallic reference complex, indicating the two Co-salen units on the cyclic framework may work in a cooperative manner. Specifically, Co3, with the most flexible cyclic framework exhibits the best catalytic performance among the three catalysts, due to the efficient cooperative interactions between two cobalt centers.
Wu, Fengshou,Wang, Kai,Li, Zaoying,Zhu, Xunjin
p. 101 - 104
(2015/05/27)

Dinuclear salen cobalt complex incorporating Y(OTf)3: enhanced enantioselectivity in the hydrolytic kinetic resolution of epoxides
The activation of inactive Jacobsen's chiral salen Co(ii) (salen = N,N′-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexanediamine) compound is attained by dinuclear chiral salen Co(iii)-OTf complex formation with yttrium triflate. The yttrium metal not only displays a promoting effect on electron transfer, but also assists in forming two stereocentres of a Lewis acid complex with Co(iii)-OTf. We found that the binuclear Co-complex significantly enhanced reactivity and enantioselectivity in the hydrolytic kinetic resolution of terminal epoxides compared to its analogous monomer and kinetic data are also consistent with these results.
Patel, Deepak,Kurrey, Ganesh Ram,Shinde, Sandip S.,Kumar, Pradeep,Kim, Geon-Joong,Thakur, Santosh Singh
p. 82699 - 82703
(2015/10/19)

Ionophilic imidazolium-tagged cinchona ligand on LDH-immobilized osmium: Recyclable and recoverable catalytic system for asymmetric dihydroxylation reaction of olefins
Abstract A catalytic system for the asymmetric dihydroxylation of olefins was developed by using an ionic-tagged biscinchona alkaloid ligand immobilized onto OsO4-exchanged layered double hydroxide (LDH) as a robust recyclable homogenous-heterogeneous catalytic system. The desired products were obtained in high yield and enantioselectivity.
Kaur, Amanpreet,Singh, Vasundhara
p. 1191 - 1194
(2015/06/02)