107-88-0Relevant academic research and scientific papers
Enantioselective hydrogenation of ketones over a tartaric acid-modified raney nickel catalyst: Substrate-modifier interaction strength and enantioselectivity
Choliq, Azka Azkiya,Murakami, Eitaro,Yamamoto, Shota,Misaki, Tomonori,Fujita, Morifumi,Okamoto, Yasuaki,Sugimura, Takashi
, p. 1325 - 1332 (2018)
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).
The in situ transformation of the co-product formaldehyde in the reversible hydrolysis of 1,3-dixoane to obtain 1,3-propanediol efficiently
Wang, Yehong,Zhang, Jian,Zhang, Zhixin,Hou, Tingting,Zhang, Chaofeng,An, Jinghua,Wang, Feng
, p. 1455 - 1458 (2018)
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.
Hydroboration. 71. Hydroboration of Representative Heterocyclic Olefins with Borane-Methyl Sulfide, 9-Borabicyclononane, Dicyclohexylborane, and Disiamylborane. Synthesis of Heterocyclic Alcohols
Brown, Herbert C.,Prasad, J. V. N. Vara,Zee, Sheng-Hsu
, p. 1582 - 1589 (1985)
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.
One-pot synthesis of 1,3-butanediol by 1,4-anhydroerythritol hydrogenolysis over a tungsten-modified platinum on silica catalyst
Asano, Takehiro,Liu, Lujie,Nakagawa, Yoshinao,Tamura, Masazumi,Tomishige, Keiichi
, p. 2375 - 2380 (2020)
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.
C-O bond hydrogenolysis of cyclic ethers with OH groups over rhenium-modified supported iridium catalysts
Chen, Kaiyou,Mori, Kazuma,Nakagawa, Yoshinao,Tomishige, Keiichi,Watanabe, Hideo
, p. 171 - 183,13 (2012)
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.
Selective hydrogenolysis of polyols and cyclic ethers over bifunctional surface sites on rhodium-rhenium catalysts
Chia, Mei,Pagan-Torres, Yomaira J.,Hibbitts, David,Tan, Qiaohua,Pham, Hien N.,Datye, Abhaya K.,Neurock, Matthew,Davis, Robert J.,Dumesic, James A.
, p. 12675 - 12689 (2011)
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.
ZnCl2-catalyzed hydrodefluorination of gem-difluoromethylene derivatives with lithium aluminum hydride
Cheng, Jianhang,Wu, Jingjing,Cao, Song
, p. 3481 - 3484 (2011)
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.
Non-catalytic conversion of C-F bonds of gem-difluoromethylene derivatives to C-H bonds with lithium aluminum hydride under room temperature
Wu, Jing-Jing,Cheng, Jian-Hang,Zhang, Jian,Shen, Li,Qian, Xu-Hong,Cao, Song
, p. 285 - 288 (2011)
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
Heterogeneous ceria catalyst with water-tolerant Lewis acidic sites for one-pot synthesis of 1,3-diols via prins condensation and hydrolysis reactions
Wang, Yehong,Wang, Feng,Song, Qi,Xin, Qin,Xu, Shutao,Xu, Jie
, p. 1506 - 1515 (2013)
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.
Electrochemistry for the generation of renewable chemicals: Electrochemical conversion of levulinic acid
Dos Santos, Tatiane R.,Nilges, Peter,Sauter, Waldemar,Harnisch, Falk,Schr?der, Uwe
, p. 26634 - 26643 (2015)
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.
