- Enantioselective hydrogenation of ketones over a tartaric acid-modified raney nickel catalyst: Substrate-modifier interaction strength and enantioselectivity
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Chiral (R,R)-tartaric acid and NaBr-doubly modified Raney nickel (TA-MRNi) is a promising heterogeneous catalyst for enantioselective hydrogenation of prochiral β-keto esters. To obtain deeper insights into the factors ruling the enantioselectivity, enantiodifferentiating hydrogenation of substituted ketones was studied over TA-MRNi and NaBr-modified RNi by use of combined individual-competitive hydrogenation techniques. Relative equilibrium adsorption constants of the substrates were estimated to evaluate their relative interaction strength with adsorbed tartaric acid moiety. DFT calculations were also performed to estimate the interaction energy through hydrogen bonding, providing clear support to the kinetic analysis and surface model. It is concluded with the enantioselective hydrogenation of ketones over TA-MRNi that the enantioselectivity increases as the substrate-modifier interaction strength increases: Methyl acetoacetate (MAA) > acetylacetone (AA) ～ 4-hydroxy-2-butanone (HB) > 2-octanone (2O).
- Choliq, Azka Azkiya,Murakami, Eitaro,Yamamoto, Shota,Misaki, Tomonori,Fujita, Morifumi,Okamoto, Yasuaki,Sugimura, Takashi
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- The in situ transformation of the co-product formaldehyde in the reversible hydrolysis of 1,3-dixoane to obtain 1,3-propanediol efficiently
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Herein, a strategy is developed for efficient production of l,3-propanediol via the hydrolysis of 1,3-dioxane by the in situ transformation of the co-product formaldehyde (HCHO) in the presence of Eu(OH)3. The reversible hydrolysis reaction is promoted to yield 98% conversion and 99% 1,3-propanediol selectivity. Furthermore, HCHO is converted to formic acid (HCOOH) which could act as an acidic catalyst in the hydrolysis of 1,3-dioxane. The combination of FT-IR and control experiments demonstrates that HCOOH is generated via the hydrolysis of formate species which formed on the surface of Eu(OH)3.
- Wang, Yehong,Zhang, Jian,Zhang, Zhixin,Hou, Tingting,Zhang, Chaofeng,An, Jinghua,Wang, Feng
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- Hydroboration. 71. Hydroboration of Representative Heterocyclic Olefins with Borane-Methyl Sulfide, 9-Borabicyclononane, Dicyclohexylborane, and Disiamylborane. Synthesis of Heterocyclic Alcohols
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The hydroboration of representative heterocycles bearing an endocyclic double bond with borane-methyl sulfide (BMS), 9-borabicyclononane (9-BBN), dicyclohexylborane (Chx2BH), and disiamylborane (Sia2BH) was investigated systematically to establish the optimum conditions for the clean and quantitative hydroboration.The hydroboration of 2,3- and 2,5-dihydrofurans with BMS (3:1 molar ratio) at 25 deg C for 1 h affords the trialkylborane, readily oxidized to 3-hydroxytetrahydrofuran in excellent yield.However, preparation of the corresponding dialkylboranes from these olefins using 2 olefin/BMS was not possible even at 0 deg C.Excess hydride and prolongated reaction time cause ring cleavage of the alkylboranes to yield both unsaturated alcohol and the dihydroborated products 1,3- and 1,4-pentanediols.Hydroboration of both 2,3-dihydrothiophene and 2-methyl-4,5-dihydrofuran with BMS proceeds cleanly to the trialkylborane stage, oxidized to the corresponding alcohols in almost quantitative yields.Hydroboration of 3-pyrroline with BMS could not be achieved with the unprotected nitrogen atom.Such hydroboration could be accomplished by protecting the nitrogen atom with the benzyloxycarbonyl group affording the trialkylborane, readily converted to N-(benzyloxycarbonyl)-3-pyrrolidinol in good yield.Conditions for a clean hydroboration of these heterocyclic five-membered olefins with 9-BBN, Chx2BH, and Sia2BH were also established.In all cases clean trialkylboranes were obtained, readily oxidized to heterocyclic alcohols in high yields. 3,4-Dihydropyran, on hydroboration with BMS, followed by oxidation, affords 3-hydroxytetrahydropyran in good yield.However, ring cleavage in this case is greater when compared to 2,3-dihydrofuran. 2-Methoxy- or 2-ethoxy-3,4-dihydro-2H-pyran readily undergo hydroboration with BMS to the trialkylboranes, oxidized to the corresponding trans and cis alcohols in a 7:3 ratio.As the steric requirements of the dialkylborane are increased, more trans alcohol is formed.Thus at 0 deg C, the ratios of trans to cis alcohols were increased from 1:1 to 7:3 and then to 8:2 with 9-BBN, Chx2BH, and Sia2BH, respectively.N-(Benzyloxycarbonyl)-1,2,3,6-tetrahydropyridine is readily hydroborated with BMS, 9-BBN, Chx2BH, and Sia2BH to the corresponding trialkylboranes, readily oxidized to N-(benzyloxycarbonyl)-3- and -4-piperidinols in good yield.Strongly basic groups in the heterocyclic ring can greatly reduce the ease of hydroboration, and the introduction of boron β to the heteroatom can lead to elimination.However, both problems can be avoided to provide ready hydroboration-oxidation of heterocyclic olefins.
- Brown, Herbert C.,Prasad, J. V. N. Vara,Zee, Sheng-Hsu
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- One-pot synthesis of 1,3-butanediol by 1,4-anhydroerythritol hydrogenolysis over a tungsten-modified platinum on silica catalyst
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Chemical production of 1,3-butanediol from biomass-derived compounds was first reported by 1,4-anhydroerythritol hydrogenolysis over a Pt-WOx/SiO2 catalyst. The reaction proceeded by ring opening hydrogenolysis of 1,4-anhydroerythritol followed by selective removal of secondary OH groups in 1,2,3-butanetriol, and an overall 1,3-butanediol yield up to 54% was then obtained. The performance of the Pt-WOx/SiO2 catalyst for 1,4-anhydroerythritol hydrogenolysis was closely correlated with that for glycerol hydrogenolysis to 1,3-propanediol. The optimized Pt-WOx/SiO2 (Pt: 4 wt% and W: 0.94 wt%) catalyst showed 57% yield of 1,3-propanediol.
- Asano, Takehiro,Liu, Lujie,Nakagawa, Yoshinao,Tamura, Masazumi,Tomishige, Keiichi
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- C-O bond hydrogenolysis of cyclic ethers with OH groups over rhenium-modified supported iridium catalysts
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Hydrogenolysis of tetrahydrofurfuryl alcohol to 1,5-pentanediol and other related substrates such as 3-hydroxytetrahydrofuran and 1,2-cyclohexanediol proceeds over Ir-ReOx/SiO2 catalyst. TOF values are higher than those of Rh-ReOx/SiO2, which has been reported to be an effective catalyst. The selectivity to the product, where the C-O bond neighboring the C-OH group in the substrate is dissociated, is comparable to or higher than that of Rh-ReOx/SiO2. Hydrogenolysis of most substrates except 1,2-cyclohexanediol proceeds via the direct mechanism where hydride species formed from hydrogen molecule attacks the anti-position of C-O bond. In the case of hydrogenolysis of 1,2-cyclohexanediol where attack of anti-position of C-O bond is unfavorable, indirect mechanism involving dehydrogenation to 2-hydroxycyclohexanone is responsible for the formation of cyclohexanol.
- Chen, Kaiyou,Mori, Kazuma,Nakagawa, Yoshinao,Tomishige, Keiichi,Watanabe, Hideo
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- Selective hydrogenolysis of polyols and cyclic ethers over bifunctional surface sites on rhodium-rhenium catalysts
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A ReOx-promoted Rh/C catalyst is shown to be selective in the hydrogenolysis of secondary C-O bonds for a broad range of cyclic ethers and polyols, these being important classes of compounds in biomass-derived feedstocks. Experimentally observed reactivity trends, NH3 temperature-programmed desorption (TPD) profiles, and results from theoretical calculations based on density functional theory (DFT) are consistent with the hypothesis of a bifunctional catalyst that facilitates selective hydrogenolysis of C-O bonds by acid-catalyzed ring-opening and dehydration reactions coupled with metal-catalyzed hydrogenation. The presence of surface acid sites on 4 wt % Rh-ReOx/C (1:0.5) was confirmed by NH3 TPD, and the estimated acid site density and standard enthalpy of NH3 adsorption were 40 μmol g-1 and -100 kJ mol-1, respectively. Results from DFT calculations suggest that hydroxyl groups on rhenium atoms associated with rhodium are acidic, due to the strong binding of oxygen atoms by rhenium, and these groups are likely responsible for proton donation leading to the formation of carbenium ion transition states. Accordingly, the observed reactivity trends are consistent with the stabilization of resulting carbenium ion structures that form upon ring-opening or dehydration. The presence of hydroxyl groups that reside α to carbon in the C-O bond undergoing scission can form oxocarbenium ion intermediates that significantly stabilize the resulting transition states. The mechanistic insights from this work may be extended to provide a general description of a new class of bifunctional heterogeneous catalysts, based on the combination of a highly reducible metal with an oxophilic metal, for the selective C-O hydrogenolysis of biomass-derived feedstocks.
- Chia, Mei,Pagan-Torres, Yomaira J.,Hibbitts, David,Tan, Qiaohua,Pham, Hien N.,Datye, Abhaya K.,Neurock, Matthew,Davis, Robert J.,Dumesic, James A.
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- ZnCl2-catalyzed hydrodefluorination of gem-difluoromethylene derivatives with lithium aluminum hydride
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Hydrodefluorination of gem-difluoromethylene derivatives with lithium aluminum hydride in the presence of a catalytic amount of ZnCl2 in good to high yields was described. A possible mechanism is also suggested.
- Cheng, Jianhang,Wu, Jingjing,Cao, Song
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- Non-catalytic conversion of C-F bonds of gem-difluoromethylene derivatives to C-H bonds with lithium aluminum hydride under room temperature
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An unexpected hydrodefluorination of unactivated aliphatic C-F bonds of CF2 derivatives with LiAlH4 at room temperature without any added metal catalyst was reported. Deuterium-labeling experiments suggested that the hydrogens introduced into the products originated from LiAlH 4. Copyright
- Wu, Jing-Jing,Cheng, Jian-Hang,Zhang, Jian,Shen, Li,Qian, Xu-Hong,Cao, Song
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- Heterogeneous ceria catalyst with water-tolerant Lewis acidic sites for one-pot synthesis of 1,3-diols via prins condensation and hydrolysis reactions
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The use of a heterogeneous Lewis acid catalyst, which is insoluble and easily separable during the reaction, is a promising option for hydrolysis reactions from both environmental and practical viewpoints. In this study, ceria showed excellent catalytic activity in the hydrolysis of 4-methyl-1,3-dioxane to 1,3-butanediol in 95% yield and in the one-pot synthesis of 1,3-butanediol from propylene and formaldehyde via Prins condensation and hydrolysis reactions in an overall yield of 60%. In-depth investigations revealed that ceria is a water-tolerant Lewis acid catalyst, which has seldom been reported previously. The ceria catalysts showed rather unusual high activity in hydrolysis, with a turnover number (TON) of 260, which is rather high for bulk oxide catalysts, whose TONs are usually less than 100. Our conclusion that ceria functions as a Lewis acid catalyst in hydrolysis reactions is firmly supported by thorough characterizations with IR and Raman spectroscopy, acidity measurements with IR and 31P magic-angle-spinning NMR spectroscopy, Na+/H + exchange tests, analyses using the in situ active-site capping method, and isotope-labeling studies. A relationship between surface vacancy sites and catalytic activity has been established. CeO2(111) has been confirmed to be the catalytically active crystalline facet for hydrolysis. Water has been found to be associatively adsorbed on oxygen vacancy sites with medium strength, which does not lead to water dissociation to form stable hydroxides. This explains why the ceria catalyst is water-tolerant.
- Wang, Yehong,Wang, Feng,Song, Qi,Xin, Qin,Xu, Shutao,Xu, Jie
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- Electrochemistry for the generation of renewable chemicals: Electrochemical conversion of levulinic acid
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The oxidative and reductive electrochemical conversion of levulinic acid to its primary products valeric acid, γ-valerolactone, 2,7-octanedione, 4-hydroxy-2-butanone and 3-buten-2-one is studied in detail. The reactions were performed in aqueous solutions and at ambient temperature, following the principles of green chemistry. The obtained primary reaction products were studied with respect to the oxidative and reductive electrochemical formation of secondary products, such as n-octane, 1-butanol and 1,3-butanediol. It is shown that the choice of electrolyte composition, educt concentration and the nature of the electrode material has a strong influence on the selectivity of product formation. For instance it is demonstrated that in alkaline solutions γ-valerolactone can be gained from levulinic acid at iron electrodes with similar Coulombic efficiency (～20%) but higher selectivity (S = 70%) than on lead (S = 50%). Furthermore, for the first time the electrochemical two-step reaction of levulinic acid to 1-butanol via 4-hydroxy-2-butanone is reported. For some of the reaction pathways the main product is water insoluble, which allows a direct separation of the product and the potential electrolyte reuse in a semi-continuous process. Especially the use of the electrocatalytic hydrogenation may provide a path for the storage of electricity into liquid organic fuels as shown by a basic energetic assessment of all electrochemical conversions.
- Dos Santos, Tatiane R.,Nilges, Peter,Sauter, Waldemar,Harnisch, Falk,Schr?der, Uwe
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- Directing activator-assisted regio- and oxidation state-selective aerobic oxidation of secondary C(sp3)-H bonds in aliphatic alcohols
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The regioselective conversion of an unactivated C(sp3)-H bond of a methylene carbon (CH2) into a C-O single bond is an attractive reaction in organic synthesis. Herein, we present a strategy for a regio- and oxidation state-selective aerobic C-H oxidation based on an N-hydroxyamide-derived directing activator (DA), which is attached to a hydroxy group in alcohol substrates. The DA reacts with NOx species generated in situ from NaNO2, a Br?nsted acid, and aerobic oxygen, and effectively generates an amidoxyl radical from the N-hydroxy moiety of the DA. Then, the amidoxyl radical promotes site-selective intramolecular C-H abstraction from methylenes with γ- (or δ-) selectivity. The thus-generated methylene radicals are trapped by molecular oxygen and NO. This process results in the predominant formation of nitrate esters as products, which suppresses undesired overoxidation. The products can be easily converted into alcohols after hydrogenolysis.
- Ni, Jizhi,Ozawa, Jun,Oisaki, Kounosuke,Kanai, Motomu
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- A porous metal-organic aerogel based on dirhodium paddle-wheels as an efficient and stable heterogeneous catalyst towards the reduction reaction of aldehydes and ketones
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A new metal-organic aerogel (MOA-Rh-2) containing dirhodium paddle-wheels has been prepared from the reaction of dirhodium(ii) tetracarboxylate (Rh2(OAc)4) and tetrakis(4-carboxyphenyl)porphyrin (TCPP) in a mixed solvent of DMF and water, followed by supercritical CO2 extraction. MOA-Rh-2 has been fully characterized by ICP-OES, EDS, XPS, PXRD, SEM, TEM and TGA. Its porosity has been confirmed by N2 adsorption isotherms at 77 K, and the Barrett-Joyner-Halenda pore size is centered at 3.5 nm. The existence of mesopores has been further verified by dye adsorption tests using methylene blue (14.4 × 6.1 ?2) and rhodamine B (15.8 × 11.8 × 6.8 ?3). MOA-Rh-2 is air and moisture-stable. The catalytic results show that, under an air atmosphere and at ambient temperature, a low loading (0.1-0.4 mol%) of MOA-Rh-2 can efficiently promote the hydrosilylation of aldehydes and ketones with the commercially available silane of PhSiH3. After catalytic reactions, MOA-Rh-2 can be recycled and reused for 5 runs without significant loss of the activity, and the reaction conversions are in the range of 89-99%.
- Liu, Gang,Wang, Yanhu,Zhu, Baofu,Zhang, Li,Su, Cheng-Yong
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- METHOD FOR PRODUCING ALCOHOL
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The present invention provides a method for selectively producing an alcohol by efficiently hydrogenating a lactone. The present invention is a method for producing an alcohol, the method including hydrogenating a substrate lactone represented by Formula (1), in the presence of a catalyst described below, to produce an alcohol that is represented by Formula (2). In the formulae, R represents a divalent hydrocarbon group which may have a hydroxyl group. The catalyst comprises: metal species including M1 and M2; and a support supporting the metal species, and wherein M1 is rhodium, platinum, ruthenium, iridium, or palladium; M2 is tin, vanadium, molybdenum, tungsten, or rhenium; and the support is hydroxyapatite, fluorapatite, hydrotalcite, or ZrO2.
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Paragraph 0104; 0106
(2022/02/05)
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- 1,3-BUTYLENE GLYCOL PRODUCT
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To provide a high-purity 1,3-butylene glycol product which is colorless and odorless and is less likely to be colored with a lapse of time.SOLUTION: In a gas chromatographic analysis under specific conditions, an area ratio of a peak of 1,3-butylene glycol is 99.5% or more, and an APHA after holding at 180°C for 3 hours in an air atmosphere is 40 or less. When the relative retention time of the peak of 1,3-butylene glycol is 1.0, an area ratio of a peak appearing in the relative retention time in the range of 2.3 to 2.4 is more than 0 ppm and 150 ppm or less. A component applicable to the peak which appears in the relative retention time in the range of 2.3 to 2.4 includes an acetal product of 1,3-butylene glycol and acetaldol.SELECTED DRAWING: Figure 1
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Paragraph 0060
(2021/03/19)
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- METHOD FOR PRODUCING 1,3-BUTANEDIOL
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PROBLEM TO BE SOLVED: To achieve high conversion rates and selectivity coefficients in producing 1,3-butanediol by performing the hydrogenation of acetaldol obtained by the condensation of acetaldehyde. SOLUTION: A method for producing 1,3-butanediol includes hydrogenating acetaldol with a hydrogen gas, using a hydrogenation catalyst. From a reaction solution after hydrogenation, a low-boiling component of a reaction by-product is separated and collected, and all or part of the low-boiling component is used to dilute acetaldol as raw material, after which hydrogenation is performed. SELECTED DRAWING: None COPYRIGHT: (C)2021,JPOandINPIT
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Paragraph 0046-0049
(2021/04/23)
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- Method for preparing alcohol compound through hydrogenation of carbonyl-containing compound
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The invention provides a method for preparing an alcohol compound through hydrogenation of a carbonyl-containing compound, the method comprises the following steps: firstly, contacting the carbonyl-containing compound with a nickel catalyst precursor to obtain a nickel-containing solution, then carrying out a contact reaction on the nickel-containing solution and hydrogen, converting the contained nickel into a nickel catalyst, and carrying out in-situ catalysis on the hydrogenation reaction of the carbonyl-containing compound, and obtaining the alcohol compound. According to the preparation method provided by the invention, the preparation of the nickel catalyst and the hydrogenation reaction of the carbonyl-containing compound are carried out in the same technological process for the first time, the prepared nickel catalyst is good in catalytic activity and long in service life, and the alcohol compound prepared by in-situ catalysis is high in yield and good in selectivity, so that the production cost of the alcohol compound can be remarkably reduced, the production efficiency is improved, and the method is particularly suitable for large-scale industrial production.
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Paragraph 0050-0055
(2021/07/10)
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- Hydrodeoxygenation of C4-C6 sugar alcohols to diols or mono-alcohols with the retention of the carbon chain over a silica-supported tungsten oxide-modified platinum catalyst
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The hydrodeoxygenation of erythritol, xylitol, and sorbitol was investigated over a Pt-WOx/SiO2 (4 wt% Pt, W/Pt = 0.25, molar ratio) catalyst. 1,4-Butanediol can be selectively produced with 51% yield (carbon based) by erythritol hydrodeoxygenation at 413 K, based on the selectivity over this catalyst toward the regioselective removal of the C-O bond in the -O-C-CH2OH structure. Because the catalyst is also active in the hydrodeoxygenation of other polyols to some extent but much less active in that of mono-alcohols, at higher temperature (453 K), mono-alcohols can be produced from sugar alcohols. A good total yield (59%) of pentanols can be obtained from xylitol, which is mainly converted to C2 + C3 products in the literature hydrogenolysis systems. It can be applied to the hydrodeoxygenation of other sugar alcohols to mono-alcohols with high yields as well, such as erythritol to butanols (74%) and sorbitol to hexanols (59%) with very small amounts of C-C bond cleavage products. The active site is suggested to be the Pt-WOx interfacial site, which is supported by the reaction and characterization results (TEM and XAFS). WOx/SiO2 selectively catalyzed the dehydration of xylitol to 1,4-anhydroxylitol, whereas Pt-WOx/SiO2 promoted the transformation of xylitol to pentanols with 1,3,5-pentanetriol as the main intermediate. Pre-calcination of the reused catalyst at 573 K is important to prevent coke formation and to improve the reusability.
- Betchaku, Mii,Cao, Ji,Liu, Lujie,Nakagawa, Yoshinao,Tamura, Masazumi,Tomishige, Keiichi,Yabushita, Mizuho
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supporting information
p. 5665 - 5679
(2021/08/16)
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- Method for synthesizing 1, 3-dihydric alcohol by using olefin and methanol as raw materials
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The invention discloses a method for preparing 1, 3-dihydric alcohol by taking olefin and methanol as raw materials through one-step reaction and a catalyst for the method. The method comprises the following steps: 1) adding a catalyst into a reactor, heating and reducing in a hydrogen-nitrogen mixed atmosphere, then cooling to 60-180 DEG C, and keeping the pressure in the reactor to be 0.5-8 MPa for reaction; 2) respectively introducing olefin and a methanol aqueous solution into the reactor for reaction, wherein the airspeed is 0.01-10h in terms of methanol; 3) enabling that the reaction product enters a product storage tank after condensation and gas-liquid separation; and 4) carrying out rectification separation on the reaction product obtained in the step 3) to obtain a 1, 3-dihydric alcohol product with the purity of more than 99%. The method provided by the invention has the advantages of low raw material cost, simple steps and continuous production.
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Paragraph 0094-0120
(2021/07/28)
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- Method for preparing 1, 3-butanediol through acetaldehyde condensation
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The invention discloses a method for preparing 1, 3-butanediol through acetaldehyde condensation, which comprises the following steps: 1) adding 1, 3-butanediol and a solid acid catalyst into acetaldehyde condensation reaction liquid, and enabling 3-hydroxybutyraldehyde and condensation byproducts in the reaction liquid to completely react with the 1, 3-butanediol to generate an intermediate; and 2) rectifying to separate out acetaldehyde, and then hydrolyzing and hydrogenating the reaction liquid to generate the product 1, 3-butanediol from the intermediate generated in the reaction. The preparation method has the main advantages of high acetaldehyde recovery rate (greater than or equal to 95%), easiness in separation, low production cost, simplicity in operation and the like, and is suitable for industrial production.
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Paragraph 0041-0049; 0053; 0060-0061; 0065-0090
(2021/05/12)
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- Chemoenzymatic Buta-1,3-diene Synthesis from Syngas Using Biological Decarboxylative Claisen Condensation and Zeolite-Based Dehydration
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A method for producing buta-1,3-diene (1,3-BD) by an amalgamation of chemical and biological approaches with syngas as the carbon source is proposed. Syngas is converted to the central intermediate, acetyl-CoA, by microorganisms through a tetrahydrofolate metabolism pathway. Acetyl-CoA is subsequently converted to malonyl-CoA using a carbonyl donor in the presence of a carboxylase enzyme. A decarboxylative Claisen condensation of malonyl-CoA and acetaldehyde ensues in the presence of acyltransferases to form 3-hydroxybutyryl-CoA, which is subsequently reduced by aldehyde reductase to give butane-1,3-diol (1,3-BDO). An ensuing dehydration step converts 1,3-BDO to 1,3-BD in the presence of a chemical dehydrating reagent.
- Balasubramaniam, Sivaraman,Badle, Sneh,Badgujar, Swati,Veetil, Vinod P.,Rangaswamy, Vidhya
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p. 705 - 711
(2020/12/01)
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- Preparation method of 1,3-butanediol
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The invention provides a preparation method of 1,3-butanediol, which comprises the following steps: acetaldehyde condensation, hydrogenation and separation. In the hydrogenation step, the purity of the prepared 1,3-butanediol is greater than 99.5% by adopting methods of staged hydrogenation, addition of a modifier into a hydrogenation catalyst and the like, the content of 1,3-dioxane impurity canbe reduced to 0.01 wt% or below, and the product is odorless. The method has the advantages of simple process, low energy consumption, simple operation, high yield and selectivity of 1,3-butanediol, high purity of 1,3-butanediol and the like, and odorless 1,3-butanediol can be obtained.
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Paragraph 0077; 0078; 0079; 0080; 0081
(2020/03/05)
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- Method for improving selectivity of aldol condensation reaction
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The invention provides a method for improving selectivity of aldol condensation reaction. The method comprises the following steps: introducing C1-C5 aldehyde participating in the reaction and an aqueous solution of an alkaline compound into a coiled tube type reactor in a parallel flow manner, forming a continuous phase under a turbulence condition by the aqueous solution of the alkaline compound, and dispersing the C1-C5 aldehyde in the continuous phase in a droplet form. The C1-C5 aldehyde is selected from one or two of formaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, isobutyraldehyde, n-valeraldehyde and isovaleraldehyde; the alkaline compound is selected from at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate,ammonia water, trimethylamine, triethylamine and diisopropylamine. The invention also provides preparation of 1, 3-butanediol by condensation of acetaldehyde and an inorganic alkali compound and preparation of hydroxypivalaldehyde by condensation of formaldehyde, isobutyraldehyde and a trimethylamine aqueous solution. With application of the coiled tube type reactor, the reaction temperature, thematerial ratio and the retention time can be accurately controlled, side reactions are effectively reduced, and the reaction efficiency, the reaction stability and the product selectivity are improvedby adopting the reaction process.
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Paragraph 0024-0027; 0031-0036
(2020/09/16)
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- 1, 3 - Butylene glycol product
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[Problem] to provide an odorless, water hardly increase with time even in a state where the acid concentration, 1, 3 - butylene glycol product in high purity. The specific conditions in the gas chromatography analysis [solution], 1, 3 - butylene glycol 1.0 when the relative retention time of a peak, the peak of 1, 3 - butylene glycol is 100 ppm or less and the area ratio range of 1.35 - 1.45 relative retention time appears in the product. Figure 1 [drawing]
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Paragraph 0051
(2021/01/08)
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- 1, 3 - Butylene glycol product
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[A] · a colorless and odorless, and lapse of time hardly colored, highly pure 1, 3 - butylene glycol product. The specific conditions in the gas chromatography analysis [solution], 1, 3 - butylene glycol 1.0 when the relative retention time of a peak, the peak area ratio of 1, 3 - butylene glycol is less than 1000 ppm relative retention time 2.3 - 2.4 appear product. Figure 1 [drawing]
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Paragraph 0053
(2021/01/08)
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- Method for preparing 1, 3-butanediol
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The invention provides a method for preparing 1, 3-butanediol. The method comprises the following steps: (1) carrying out condensation cyclization reaction on butadiene, water and an aldehyde ketone compound according to a certain material ratio in the presence of hydrogen peroxide and a catalyst A to obtain a reaction solution containing an intermediate I; and (2) mixing the reaction solution containing the intermediate I with a certain amount of water, and carrying out hydrolysis reaction in the presence of a catalyst B to obtain 1, 3-butanediol and a corresponding aldehyde ketone compound.Compared with the existing production method, the method has the advantages of accessible reaction raw materials, high reaction conversion rate, high selectivity and the like, and is suitable for industrial production.
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Paragraph 0061; 0064-0066; 0076; 0077
(2020/11/22)
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- High purity 1,3-butanediol and its preparation method
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The present invention relates to a high purity 1,3-butanediol and a preparation method thereof. The preparation method of the present invention comprises: a step (a) of mixing distilled water, a buffer solution and paraformaldehyde to obtain a mixture, and heating the mixture to prepare formaldehyde; a step (b) of mixing formaldehyde of the step (a) (s100) with acetone, and making the formaldehyde of the step (a) react with the acetone to prepare a mixed solution as an intermediate; a step (c) of reducing the intermediate of the step (b) (s200) to prepare 1,3-butanediol; and a step (d) of deodorizing/purifying 1,3-butanediol of the step (c) (s300). According to the present invention, the high purity 1,3-butanediol prepared by the preparation method not only can be used as raw material for various resins such as polyester resins, alkyd resins, urethane resins, urethane coatings and the like as industrial uses, but also can be diversely used in other fabric softeners, pharmaceuticals, dyestuffs and others. Further, the high purity 1,3-butanediol not only can be used as a moisturizer for a cosmetic composition, perfume and hair since slight intoxication is not generated although the high purity 1,3-butanediol is stored for a long period, but also can be used in a preparation for spice of food products or the like.(AA) Start(BB) End(S10) Step of preparing high purity formaldehyde(S200) Step of preparing an intermediate(S300) Step of reducing the intermediate(S400) Step of performing deodorizing and purifying operationsCOPYRIGHT KIPO 2019
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Paragraph 0172; 0184-0188; 0190-0203; 0223-0234; 0238
(2019/05/25)
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- Method for synthesizing diene compounds based on aldehyde-ketone condensation reaction
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The invention provides a method for synthesizing diene compounds based on an aldehyde-ketone condensation reaction. The method comprises the following steps: firstly, under the action of a condensation catalyst, performing a condensation reaction on ketone compounds and aldehyde compounds to obtain condensation products; then, under the action of a reduction catalyst, performing a reduction reaction on the condensation products obtained in the previous step to obtain reduction products; under the action of a catalyst, performing a dehydration reaction on the reduction products obtained in theprevious step to obtain the diene compounds. According to the method, ketone, aldehyde as well as homologues of ketone and aldehyde which are cheap and easy to obtain can be used as raw materials forsynthesizing the diene compounds such as butadiene, piperylene as well as homologues of butadiene and piperylene, experimental conditions are mild, the operation is simple, and a large-scale synthesisprospect is achieved.
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Paragraph 0156; 0161-0165; 0205; 0209; 0210
(2019/05/08)
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- Preparation method of 1, 3-butylene glycol
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The invention provides a preparation method of 1, 3-butylene glycol. The preparation method comprises following steps: A, acetaldehyde is introduced into a fixed bed reactor, under the effect of a supported type solid basic catalyst, aldol condensation reaction is carried out so as to obtain 3-hydroxybutyraldehyde; and B, 3-hydroxybutyraldehyde is subjected to continuous hydrogenation reaction inthe fixed bed reactor so as to obtain 1, 3-butylene glycol. According to the preparation method, the fixed bed reactor is adopted, at the same time, the supported type solid basic catalyst is adoptedto replace a conventional liquid alkali (such as sodium hydroxide) catalysts, and in the step of hydrogenation reduction, a supported nickel hydrogenation catalyst is adopted. The preparation method is capable of solving problems in the prior art product quality is poor, product yield is low, technology process is complex, and a large amount of waste water and waste residue is generated; aldol condensation quenching step is avoided; side reactions are reduced; relatively high reaction conversion rate and yield are achieved; no neutralizing or desalting process is needed in reaction process; and great improvement of traditional 1, 3-butylene glycol preparation technology is realized.
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Page/Page column 5-7
(2019/03/26)
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- Capping experiments reveal multiple surface active sites in CeO2 and their cooperative catalysis
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Understanding of surface active sites (SAS) of CeO2 is crucial to its catalytic applications. In the present study, we have employed capping experiments, DFT calculations, and spectroscopic characterization to study pristine CeO2 catalyst. We find that multiple SAS coexist on the CeO2 surface: oxygen vacancies as redox sites and the coordinately unsaturated Ce cations near the oxygen vacancies and the neighboring oxygen ions as Lewis acid-base sites. Dimethylsulfoxide (DMSO), pyridine, and benzoic acid are utilized to cap the redox sites, Lewis acid sites, and base sites, respectively. Selective capping on the redox site does not have much effect on the acid-base catalysis, and vice versa, indicating the distinct surface proximity and independent catalysis of these SAS. We draw attention to a relationship between the well-known redox sites and the surface Lewis acid and Lewis base pairs on CeO2 surface, which are responsible for driving various heterogeneous catalytic reactions.
- Ren, Xiaoning,Zhang, Zhixin,Wang, Yehong,Lu, Jianmin,An, Jinghua,Zhang, Jian,Wang, Min,Wang, Xinkui,Luo, Yi
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p. 15229 - 15237
(2019/05/27)
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- Transfer Hydrogenation of Aldehydes and Ketones with Isopropanol under Neutral Conditions Catalyzed by a Metal-Ligand Bifunctional Catalyst [Cp?Ir(2,2′-bpyO)(H2O)]
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A Cp?Ir complex bearing a functional bipyridonate ligand [Cp?Ir(2,2′-bpyO)(H2O)] was found to be a highly efficient and general catalyst for transfer hydrogenation of aldehydes and chemoselective transfer hydrogenation of unsaturated aldehydes with isopropanol under neutral conditions. It was noteworthy that many readily reducible or labile functional groups such as nitro, cyano, ester, and halide did not undergo any change under the reaction conditions. Furthermore, this catalytic system exhibited high activity for transfer hydrogenation of ketones with isopropanol. Notably, this research exhibited new potential of metal-ligand bifunctional catalysts for transfer hydrogenation.
- Wang, Rongzhou,Tang, Yawen,Xu, Meng,Meng, Chong,Li, Feng
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p. 2274 - 2281
(2018/02/23)
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- Hydrogenation of CO2-Derived Carbonates and Polycarbonates to Methanol and Diols by Metal–Ligand Cooperative Manganese Catalysis
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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
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supporting information
p. 13439 - 13443
(2018/09/21)
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- N-substituted imidazole carboxylate compound, preparation method and medical uses thereof
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The present invention relates to a compound represented by a general formula (I) or a stereoisomer, a solvate, a pharmaceutically acceptable salt or a eutectic, a composition, a preparation method and medical uses thereof, wherein the general formula (I) is defined in the specification, and each substituent is defined in the specification.
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Paragraph 0283-0288
(2017/12/13)
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- PROCESS FOR PRODUCING 1,3-BUTANEDIOL AND FOR OPTIONALLY FURTHER PRODUCING (R)-3-HYDROXYBUTYL (R)-3-HYDROXYBUTYRATE
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A process is described for producing 1,3-butanediol, wherein an ester of poly-(R)-3-hydroxybutyrate such as formed by transesterification with an alcohol is reduced by hydrogenation in the presence of a skeletal copper-based catalyst to provide 1,3-butanediol. The 1,3-butanediol may be transesterified by reaction with additional poly-(R)-3-hydroxybutyrate ester to produce (R)-3-hydroxybutyl (R)-3-hydroxybutyrate.
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Paragraph 0036-0038
(2017/08/01)
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- Selective C?O Hydrogenolysis of Erythritol over Supported Rh-ReOx Catalysts in the Aqueous Phase
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Bimetallic Rh-ReOx (Re/Rh molar ratio 0.4–0.5) catalysts supported on TiO2 and ZrO2 were prepared by the successive impregnation of dried and calcined unreduced supported Rh catalysts. Their catalytic performances were evaluated in the hydrogenolysis of erythritol to butanetriols (BTO) and butanediols (BDO) in aqueous solution at 150–240 °C under 30–120 bar H2. The activity depended on the nature of the support, and the highest selectivity to BTO and BDO at 80 % conversion was 37 and 29 %, respectively, in the presence of 3.7 wt %Rh-3.5 wt %ReOx/ZrO2 at 200 °C under 120 bar. The characterization of the catalysts by CO chemisorption, TEM with energy-dispersive X-ray spectroscopy, thermogravimetric analysis with MS, and X-ray photoelectron spectroscopy suggests a different distribution and reducibility of Re species over the supported Rh nanoparticles, which depends on the support.
- Said, Achraf,Da Silva Perez, Denilson,Perret, Noémie,Pinel, Catherine,Besson, Michèle
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p. 2768 - 2783
(2017/07/28)
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- Reactivity of the CH-bonds of 2-butanol in liquid-phase oxidation
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The kinetics of product accumulation is studied in the azodiisobutyronitrile-initiated oxidation of 2-butanol. The relative reactivity for all types of the CH-bonds of 2-butanol is determined for reactions with peroxyl radicals at 60°C. It is established that the hydroxyl functional group of 2-butanol activates the CHbond in position 2 (α) and deactivates CH-bonds in positions 1, 3 (β), and 4 (γ), compared to the corresponding CH-bonds of saturated hydrocarbons.
- Puchkov,Nepomnyashchikh, Yu. V.
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p. 2337 - 2343
(2017/11/09)
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- Degradation of a cationic dye (Rhodamine 6G) using hydrodynamic cavitation coupled with other oxidative agents: Reaction mechanism and pathway
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In the present study, decolorization and mineralization of a cationic dye, Rhodamine 6G (Rh6G), has been carried out using hydrodynamic cavitation (HC). Two cavitating devices such as slit and circular venturi were used to generate cavitation in HC reactor. The process parameters such as initial dye concentration, solution pH, operating inlet pressure, and cavitation number were investigated in detail to evaluate their effects on the decolorization efficiency of Rh6G. Decolorization of Rh6G was marginally higher in the case of slit venturi as compared to circular venturi. The kinetic study showed that decolorization and mineralization of the dye fitted first-order kinetics. The loadings of H2O2 and ozone have been optimized to intensify the decolorization and mineralization efficiency of Rh6G using HC. Nearly 54% decolorization of Rh6G was obtained using a combination of HC and H2O2 at a dye to H2O2 molar ratio of 1:30. The combination of HC with ozone resulted in 100% decolorization in almost 5-10 min of processing time depending upon the initial dye concentration. To quantify the extent of mineralization, total organic carbon (TOC) analysis was also performed using various processes and almost 84% TOC removal was obtained using HC coupled with 3 g/h of ozone. The degradation by-products formed during the complete degradation process were qualitatively identified by liquid chromatography-mass spectrometry (LC-MS) and a detailed degradation pathway has been proposed.
- Rajoriya, Sunil,Bargole, Swapnil,Saharan, Virendra Kumar
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p. 183 - 194
(2016/06/06)
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- Method used for preparing 1,3-dihydric alcohol via Prins condensation reaction
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The invention relates to a method used for preparing a 1,3-dihydric alcohol via Prins condensation reaction. According to the method, an olefin and a formaldehyde aqueous solution are taken as reaction substrates, and direct preparation of the 1,3-dihydric alcohol is carried out under catalytic effect of an acidic composite metal oxide. The reaction process comprises following steps: the formaldehyde aqueous solution is mixed with a catalyst, and an obtained mixture is delivered into a pressure vessel for sealing; the olefin gas is added, stirring is carried out, and reaction is carried out for more than 2h at a temperature higher than 80 DEG C. After reaction, the catalyst is easily collected via separation from a reaction system, and can be recycled for a plurality of time, and the highest yield of the 1,3-dihydric alcohol is 90%.
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Paragraph 0119; 0120
(2016/10/10)
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- MODIFIED MICROORGANISMS AND METHODS FOR PRODUCTION OF USEFUL PRODUCTS
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The invention provides non-naturally occurring microbial organisms and related methods, processes and materials wherein the microbial organisms includes a genetic modification which enhances production of 3-hydroxybutanal or a downstream product of 3- hydroxybutanal such as 1,3-butanediol from endogenous central metabolic intermediates such as acetyl CoA or pyruvate which are converted to acetaldehyde, whereby two molecules of acetaldehyde are condensed to form said 3-hydroxybutanal using an aldolase capable of accepting acetaldehyde as both the acceptor and donor in an aldol condensation. The aldolase may be a deoxyribose phosphate aldolase type enzyme, and is typically introduced into the organisms. The invention provides for energetically favorable pathways for production of 3-hydroxybutanal or downstream products thereof.
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Page/Page column 83-84
(2016/08/03)
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- Epoxide hydrolysis and alcoholysis reactions over crystalline Mo-V-O oxide
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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
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p. 70842 - 70847
(2016/08/05)
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- A method for producing isomaltooligo hydrogenolytic
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PROBLEM TO BE SOLVED: To provide a production method for an erythritol hydrogenolysis product, including hydrocracking the erythritol on mild conditions to efficiently obtain butane-mono, di or triol.SOLUTION: The production method for the erythritol hydrogenolysis product comprises supplying to a reactor hydrogen and a material solution containing the erythritol and reacting in the reactor the erythritol with hydrogen in the presence of a catalyst to obtain the erythritol hydrogenolysis product, wherein, as the catalyst, a catalyst provided by supporting iridium on a carrier is used, and as the reactor, a trickle bed reactor is used. As the catalyst, at least one metal ingredient selected from the group consisting of rhenium, molybdenum, tungsten and manganese is preferably used together with the catalyst carrying the iridium on the carrier.
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Paragraph 0056; 0057; 0058
(2018/11/22)
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- The method of manufacture of a polyol hydrogenolytic
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PROBLEM TO BE SOLVED: To provide a production method for a polyol hydrogenolysis product, including hydrocracking a polyol to efficiently obtain the polyol hydrogenolysis product. SOLUTION: The production method for the polyol hydrogenolysis product comprises supplying to a reactor hydrogen and a material solution containing the polyol and reacting in the reactor the polyol with hydrogen in the presence of a catalyst to obtain the polyol hydrogenolysis product, wherein, as the catalyst, a catalyst provided by supporting on a carrier at least one metal ingredient selected from the group consisting of iridium, platinum, rhodium, cobalt and palladium, is used, and as the reactor, a metal reactor comprising a material whose iron and/or nickel ingredient content is COPYRIGHT: (C)2013,JPOandINPIT
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Paragraph 0082
(2017/01/05)
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- A method for producing isomaltooligo hydrogenolytic
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PROBLEM TO BE SOLVED: To provide a method for producing a hydrogenolysis product of erythritol, with which the erythritol is efficiently subjected to hydrogenolysis in mild conditions to provide butane-mono, di or triol.SOLUTION: The method for producing the hydrogenolysis product of erythritol includes a process of reacting the erythritol and hydrogen in the presence of a catalyst to prepare at least one of compound selected from butane-mono, di and triol, wherein, as the catalyst, a catalyst prepared by depositing at least one of metal component selected from a group comprising iridium, platinum, rhodium, cobalt, palladium and nickel is used.
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-
Paragraph 0079; 0082
(2017/01/02)
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- IMPROVED BUTANEDIOL MANUFACTURING PROCESS
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The disclosed process provides an improved process for manufacturing and recovering butanediol. More particularly, the disclosed process relates to an improved process for manufacturing and recovering butanediol from feedstock comprising butynediol in a reaction zone at reaction conditions, comprising the steps of reacting butynediol in the liquid phase and hydrogen in a reaction zone containing hydrogenation catalyst, recovering liquid phase product from the reaction zone, passing the recovered liquid phase product into a first liquid pressure let down vessel maintained at specific conditions, recovering first and second streams from the first liquid pressure let down vessel as liquid bottoms and overhead vent gas, respectively, passing the first stream liquid bottoms recovered to a second liquid pressure let down vessel maintained at specific conditions, and the second stream vent gas recovered to a vent gas cooler maintained at specific conditions, passing the gas from the vent gas cooler to a hydrogen recovery zone comprising a membrane filter, whereby the permeate comprises high purity hydrogen gas and the retentate comprises contaminants, recycling the permeate to the reaction zone, and recovering first and second streams from the second liquid pressure let down vessel as liquid bottoms comprising butanediol and overhead vent gas, respectively.
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Paragraph 0043-0045
(2015/11/10)
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- Highly versatile catalytic hydrogenation of carboxylic and carbonic acid derivatives using a Ru-triphos complex: Molecular control over selectivity and substrate scope
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The complex [Ru(Triphos)(TMM)] (Triphos = 1,1,1-tris(diphenylphosphinomethyl)ethane, TMM = trimethylene methane) provides an efficient catalytic system for the hydrogenation of a broad range of challenging functionalities encompassing carboxylic esters, amides, carboxylic acids, carbonates, and urea derivatives. The key control factor for this unique substrate scope results from selective activation to generate either the neutral species [Ru(Triphos)-(Solvent)H2] or the cationic intermediate [Ru(Triphos)-(Solvent)(H)(H2)]+ in the presence of an acid additive. Multinuclear NMR spectroscopic studies demonstrated together with DFT investigations that the neutral species generally provides lower energy pathways for the multistep reduction cascades comprising hydrogen transfer to C=O groups and C-O bond cleavage. Carboxylic esters, lactones, anhydrides, secondary amides, and carboxylic acids were hydrogenated in good to excellent yields under these conditions. The formation of the catalytically inactive complexes [Ru(Triphos)(CO)H2] and [Ru(Triphos)(μ-H)]2 was identified as major deactivation pathways. The former complex results from substrate-dependent decarbonylation and constitutes a major limitation for the substrate scope under the neutral conditions. The deactivation via the carbonyl complex can be suppressed by addition of catalytic amounts of acids comprising non-coordinating anions such as HNTf2 (bis(trifluoromethane)sulfonimide). Although the corresponding cationic cycle shows higher overall barriers of activation, it provides a powerful hydrogenation pathway at elevated temperatures, enabling the selective reduction of primary amides, carbonates, and ureas in high yields. Thus, the complex [Ru(Triphos)(TMM)] provides a unique platform for the rational selection of reaction conditions for the selective hydrogenation of challenging functional groups and opens novel synthetic pathways for the utilization of renewable carbon sources.
- Vom Stein, Thorsten,Meuresch, Markus,Limper, Dominik,Schmitz, Marc,H?lscher, Markus,Coetzee, Jacorien,Cole-Hamilton, David J.,Klankermayer, Jürgen,Leitner, Walter
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supporting information
p. 13217 - 13225
(2015/03/30)
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- Exploring the reaction conditions for Ru/C catalyzed selective hydrogenolysis of xylitol alkaline aqueous solutions to glycols in a trickle-bed reactor
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The hydrogenolysis of an alkaline aqueous solution of xylitol to mainly ethylene- and propylene-glycols was studied over a Ru/C catalyst in a high pressure fixed-bed reactor run in the trickle-bed mode with co-current downflow of liquid feed and hydrogen. The effects of reaction parameters including H 2 pressure (40-80 bar), temperature (190-200 °C) and pH values (NaOH/xylitol molar ratio in the range 0.1-0.2, pH 9-12) and residence time have been explored to increase the selectivity of this reaction to the desired ethyleneglycol product. The activity and final products distribution were much influenced by the hydrogen pressure. An optimum to afford a high conversion and a high selectivity to ethyleneglycol at different space times was found at 60 bar. The effects observed are in agreement with the reaction pathways previously proposed and the relative reaction rates of the dehydrogenation/hydrogenation and base-catalyzed reactions of the intermediates are affected by the hydrogen pressure and the concentration of the alkaline promoter.
- Auneau, Florian,Berchu, Maeva,Aubert, Guillaume,Pinel, Catherine,Besson, Michèle,Todaro, Daniela,Bernardi, Marco,Ponsetti, Tiziano,Di Felice, Renzo
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p. 100 - 106
(2014/07/07)
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- Formal hydration of non-activated terminal olefins using tandem catalysts
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The hydration of terminal olefins to secondary alcohols has been achieved using a Pd(ii)/Ru(ii) catalyst combination with high regioselectivity and yields. Both vinyl arenes and aliphatic olefins can be hydrated easily with the tandem catalyst system using a low catalyst loading of 1 mol%. The Royal Society of Chemistry 2014.
- Yang, Yongsheng,Guo, Jiayi,Ng, Huimin,Chen, Zhiyong,Teo, Peili
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supporting information
p. 2608 - 2611
(2014/03/21)
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- Facile microwave-assisted synthesis of monodispersed ball-like Ag@AgBr photocatalyst with high activity and durability
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We reported a rapid one-step microwave-assisted approach to synthesize a plasmonic photocatalyst of ball-like AgBr nanoparticles (ca. 290 nm in average diameter) with a small amount of metal Ag anchored on the surface. The obtained Ag@AgBr nanocomposites were characterized by means of X-ray diffraction, scanning electron microscopy, Transmission electron microscopy, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy and UV-visible diffuse reflectance spectroscopy. The shape, size, and compositions of the Ag@AgBr photocatalysts could be controlled by tuning the microwave irradiation time and the concentrations of polyvinylpyrrolidone (PVP) in the reaction solution. The as-prepared Ag@AgBr plasmonic photocatalysts show excellent visible-light photocatalytic performance and good reusability for decomposing organic pollutant of Rhodamine B (RhB) due to the surface plasmon resonance (SPR) effect of Ag nanoparticles. Meanwhile, the possible degradation pathways of RhB and a mechanism of the plasmonic photocatalytic process were also proposed.
- Xu, Xiang,Shen, Xiaoping,Zhou, Hu,Qiu, Dezhou,Zhu, Guoxing,Chen, Kangmin
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p. 183 - 192
(2013/05/21)
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- Asymmetric syntheses of the sex pheromones of pine sawflies, their homologs and stereoisomers
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We describe efficient and flexible enantioselective syntheses of the active enantiomers of the pheromones of pine sawflies, including the species Diprion jingyuanensis, their homologs and, stereoisomers, as well as those identified from the Chinese species Diprion jingyuanensis, i.e., 126. A total of 48 compounds, including acetates 78-101 and propanoates 102-125, have been synthesized. Our general approach towards these compounds originated from the commercially available chirons diethyl (S)- and (R)-malates, as well as ethyl (R)-3-hydroxybutanoate. The Seebach asymmetric methylation was employed in a key step to control additional configuration. Copyright
- Zheng, Jian-Feng,Lan, Hong-Qiao,Yang, Rui-Feng,Peng, Qi-Long,Xiao, Zhen-Hua,Tuo, Shi-Chuan,Hu, Kong-Zhen,Xiang, Yong-Gang,Wei, Zhen,Huang, Pei-Qiang,Zhang, Zhen
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p. 1799 - 1808,10
(2012/12/12)
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- Production of biobutanediols by the hydrogenolysis of erythritol
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The hydrogenolysis of erythritol using an Ir-ReOx/SiO 2 catalyst was performed for the production of butanediols, which are widely used as a raw material of polymers. The activity and selectivity to butanediols on Ir-ReOx/SiO2 was much higher than that on conventional hydrogenolysis catalysts. The maximum selectivity to 1,4- and 1,3-butanediols reached 33 and 12 % at 74 % conversion, respectively. The erythritol conversion and selectivity to butanediols was almost maintained during four repeating tests if small amounts of acid were added to the reaction and the catalyst was calcined again. The reaction kinetics, reactivity trends, and characterization results indicate a direct hydrogenolysis mechanism in which the hydride species on the Ir metal surface attacks the alkoxide species on the 3D ReOx clusters. Based on the production of erythritol by the fermentation of glucose and glycerol, erythritol hydrogenolysis may be a promising pathway for the production of biobutanediols. Happy hydrogenolysis: The direct hydrogenolysis of erythritol over an Ir-ReOx/SiO 2 catalyst is very effective for the production of biobutanediols. The selectivity to butanediols reached 48.0 % at 74.2 % conversion. Based on the production of erythritol by the fermentation of glucose and glycerol, erythritol hydrogenolysis will be promising in the production of biobutanediols.
- Amada, Yasushi,Watanabe, Hideo,Hirai, Yuichirou,Kajikawa, Yasuteru,Nakagawa, Yoshinao,Tomishige, Keiichi
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p. 1991 - 1999
(2013/01/15)
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- Efficient one-pot selective reduction of esters in β-ketoesters using LiHMDS and lithium aluminium hydride
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The ester functionality in β-keto esters is selectively reduced in one-pot, first by enolization using LiHMDS and then reduced with lithium aluminium hydride. This method produces β-hydroxyl ketones from the corresponding β-keto esters in high yield.
- Sivagurunathan,Raja Mohamed Kamil,Syed Shafi,Liakth Ali Khan,Ragavan, R. Venkat
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experimental part
p. 1205 - 1207
(2011/03/21)
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- The reactions of 4-chloro-2-butanol and 3-chloro-1-butanol with aqueous sodium hydroxide, and 1-chloro-2-propanol and 2-chloro-1-propanol with isopropyl amine
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The total reaction of 4-chloro-2-butanol 1 with NaOH(aq) is dominated (74%) by intramolecular substitution (SNi), besides which bimolecular substitution (SN2, 12%) and 1,4-elimination (i.e. fragmentation, contrary to earlier arguments) exhibit a significant contribution (11%). The total reaction of 3-chloro-1-butanol 2 instead is dominated by 1,4-(72%) and 1,2-elimination (25%), the substitution reactions being just observable (SNi 2% and SN2 1%). In 1 both the +I-effect and the conformational factors in the intermediate γ-chloroalkoxy anion favour the SNi-reaction, whereas in 2 the situation is opposite and the location of Cl on a secondary carbon also makes the SNi-reaction less favourable. The relative proportions of 1,4-and 1,2-eliminations for 2 can be explained by thermodynamic basis since the consequent products are more stable than the corresponding products from 1. 1-chloro-2-propanol 3 and 2-chloro-1-propanol 4 both react with isopropyl amine giving the same product, namely 1-isopropylamino-2-propanol, which indicates that the reaction proceeds through the propylene oxide intermediate. Compound 1 also reacted with isopropyl amine predominantly via SNi-reaction, giving first 2-methyloxetane which then further gave 4-isopropylamino-2-butanol, whereas 2 gave 3-isopropylamino-1-butanol through a direct S N2-reaction. ARKAT-USA, Inc.
- Pihlaja, Kalevi,Aaljoki, Kari,Lyytinen, Maija-Riitta,Huusko, Marja-Liisa,Hotokka, Marjut
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experimental part
p. 188 - 199
(2011/07/07)
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