- The influence of long-term exposure of Mg–Al mixed oxide at ambient conditions on its transition to hydrotalcite: The long-term aging of Mg–Al mixed oxide
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The paper is focused on the study of long-term aging of Mg–Al mixed oxides, which causes the rebuilding of the hydrotalcite layered structure in the presence of humidity. The novelty consists in the description of influence during the long-term aging (6 m
- Bábelová, Monika,Hájek, Martin,Kocík, Jaroslav,Strejcová, Kate?ina,Ti?ler, Zdeněk,Velvarská, Romana
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- Production of liquid fuel intermediates from furfural via aldol condensation over La2O2CO3-ZnO-Al2O3 catalyst
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Aldol condensation of furfural with acetone over basic catalysts allows the production of furanic adducts 4-(2-furyl)-3-buten-2-one (FAc, C8) and 1,5-di-2-furanyl-1,4-pentadien-3-one (F2Ac, C13)) that can be transformed into high-quality diesel
- Fang, Zhen,Kong, Xiao,Lei, Hanwu,Li, Lu-ping,Wei, Xiao-jie
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- Synthesis of jet fuel intermediates via aldol condensation of biomass-derived furfural with lanthanide catalyst
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Jet fuel precursors (4-(2-furyl)-3-buten-2-one (FAc) and 1,5-di-2-furanyl-1,4-pentadien-3-one (F2Ac)) can be produced from aldol condensation between furfural and acetone over basic catalysts. However, there is still a need to develop efficient alkaline catalysts and understand the role of alkaline sites. In this work, La2O2CO3-Al2O3 catalyst was successfully prepared by coprecipitation and the effect of preparation conditions on the properties and catalytic performance was investigated. Experiments showed that La2O2CO3 and La2O3 were formed after calcination, and the activity was greatly improved by the introduction of La2O2CO3. At higher coprecipitation pH, rod-shaped La2O2CO3 was formed, which exhibits higher exposure of basic La3+-O2? sites and shows good performance in aldol condensation reactions. The catalytic performance of La2O2CO3-Al2O3 in aldol condensation of furfural with acetone was also evaluated and compared with that of Al2O3, La2O3, La2O3-Al2O3, La(OH)?/Al2O3 and La2O2CO3/Al2O3. A total conversion of furfural can be realized with F2Ac yield of 67.8% at a furfural/acetone ratio of 1/1 and 90 °C, with a FAc yield of 25.8% at the same time. The deactivation mechanism of the La2O2CO3-Al2O3 catalyst was also studied.
- Cong, Wen-Jie,Fang, Zhen,Kong, Xiao,Li, Lu-ping
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- Methylene-Linked Bis-NHC Half-Sandwich Ruthenium Complexes: Binding of Small Molecules and Catalysis toward Ketone Transfer Hydrogenation
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The complex [Cp*RuCl(COD)] reacts with LH2Cl2 (L = bis(3-methylimidazol-2-ylidene)) and LiBun in tetrahydrofuran at 65 °C furnishing the bis-carbene derivative [Cp*RuCl(L)] (2). This compound reacts with NaBPh4 in MeOH under dinitrogen to yield the labile dinitrogen-bridged complex [{Cp*Ru(L)}2(μ-N2)][BPh4]2 (4). The dinitrogen ligand in 4 is readily replaced by a series of donor molecules leading to the corresponding cationic complexes [Cp*Ru(X)(L)][BPh4] (X = MeCN 3, H2 6, C2H4 8a, CH2CHCOOMe 8b, CHPh 9). Attempts to recrystallize 4 from MeNO2/EtOH solutions led to the isolation of the nitrosyl derivative [Cp*Ru(NO)(L)][BPh4]2 (5), which was structurally characterized. The allenylidene complex [Cp*Ru═C═C═CPh2(L)][BPh4] (10) was also obtained, and it was prepared by reaction of 2 with HCCC(OH)Ph2 and NaBPh4 in MeOH at 60 °C. Complexes 3, 4, and 6 are efficient catalyst precursors for the transfer hydrogenation of a broad range of ketones. The dihydrogen complex 6 has proven particularly effective, reaching TOF values up to 455 h-1 at catalyst loadings of 0.1% mol, with a high functional group tolerance on the reduction of a broad scope of aryl and aliphatic ketones to yield the corresponding alcohols.
- Botubol-Ares, José Manuel,Cordón-Ouahhabi, Safa,Moutaoukil, Zakaria,Collado, Isidro G.,Jiménez-Tenorio, Manuel,Puerta, M. Carmen,Valerga, Pedro
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supporting information
p. 792 - 803
(2021/04/06)
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- High efficiency photoinitiators with extremely low concentration based on furans derivative
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In this paper, two type II photoinitiators (1E,4E)1,5-di(furan-2-yl) penta-1,4-dien-3-one (DFP) and (E)-1,3-di(furan-2-yl) prop-2-en-1-one (DFP-e) were synthesized via Claisen-Schmidt reaction. The maximum peak of absorption could reach about 360 nm and the molar extinction coefficient as high as 4 × 104 M?1 cm?1, it could initiate photopolymerization of HDDA and PEGDA at very low concentration, and the photopolymerization efficiency is much higher than that of ITX at the same concentration. In addition, the synthesized initiators show higher photopolymerization efficiency for PEGDA than that of ITX in the absence of co-initiators as well. On the other hand, the initiators had high rate of photo-bleach exposure upon LED lamp, it could be appropriate for light color and colorless system. With the properties, these initiators could be a promising candidate for UV LED photopolymerization.
- Li, Jingfang,Nie, Jun,Sun, Fang,Yang, Fan,Zhao, Xiangchen,Zhong, Meijuan,Zhu, Xiaoqun
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- Synthesis and characterization of functionalized NaP Zeolite@CoFe2O4 hybrid materials: a micro–meso-structure catalyst for aldol condensation
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In this work, magnetic nanocomposite of NaP Zeolite and CoFe2O4 as magnetic nanoparticles (MNP’s) with different ratios were prepared and in the second step functionalized with 2-aminopyridine as a basic group. All samples were characterized by FT-IR, XRD, VSM, FESEM, EDX, TEM, and BET and thermal analyses. The results show that CoFe2O4 MNP’s was dispersed on NaP Zeolite without any significant aggregation with particle size about 30–50?nm. The BET and TEM confirmed the presence of mesoporous phase in the surface of NaP Zeolite/CoFe2O4 and preparation a micro–meso-structure. The NaP Zeolite/CoFe2O4 and NaP Zeolite/CoFe2O4/Am-Py were used as acid–base catalysts for aldol condensation of cyclohexanone with benzaldehyde, and furfural with acetone which produce curcumin and biofuel intermediates, respectively, in solvent-free condition. The effect of different factors such as the percent of CoFe2O4 MNP’s, catalyst amount, solvent, time and temperature was investigated. The catalyst was easily separated with an external magnet and reused four times without significant change in the yield. These catalysts have various advantages including high loading capacity, low leaching for CoFe2O4 MNP’s and simple and efficient recovery procedure which can be used under mild and ecofriendly condition.
- Mortezaei, Zohreh,Zendehdel, Mojgan,Bodaghifard, Mohammad Ali
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p. 2169 - 2193
(2020/01/29)
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- Synthesis of tetracyclic oxindoles and evaluation of their α-glucosidase inhibitory and glucose consumption-promoting activity
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A series of tetracyclic oxindole derivatives was synthesized by asymmetric 1, 3-dipole reaction in 2–4 steps in 57–86% overall yields. These compounds were evaluated for α-glucosidase inhibitory and glucose consumption-promoting activity in vitro. Compound 4l competitively and reversibly inhibited α-glucosidase (IC50 = 3.64 μM) with activity 14-fold higher than that of acarbose. Docking analysis substantiated these findings. In addition, compound 4l exhibited significant glucose consumption promoting activity at 1 μM.
- Dodd, Robert H.,Hao, Lei,Ma, Ying,Ma, Yujiao,Sun, Hua,Yu, Peng,Zhang, Xinying,Zhang, Yinan,Zhao, Lianbo
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supporting information
(2020/05/27)
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- METHOD FOR PRODUCING DIFURAN COMPOUND
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PROBLEM TO BE SOLVED: To provide a method for producing a difuran compound with high productivity by increasing a yield of the resulting difuran compound while suppressing the used amount of a base catalyst. SOLUTION: The method for producing a difuran compound of the present invention comprises reacting a furfural compound and a ketone compound in the presence of a base to produce a difuran compound. Both of the furfural compound and the ketone compound are added to a reaction vessel into which the base has been charged over a predetermined period of time of 30 minutes or longer and are reacted with them while adding both thereof in which the charged amount of the base is less than 0.75 mol equivalent based on the furfural compound. SELECTED DRAWING: None COPYRIGHT: (C)2019,JPOandINPIT
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Paragraph 0035-0038
(2019/07/09)
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- Upgrading of furfural to biofuel precursors: Via aldol condensation with acetone over magnesium hydroxide fluorides MgF2- x(OH)x
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Wastes from lignocellulosic materials, especially hemicellulose, are extremely promising resources to produce fuels from renewable raw materials. Furfural, resulting from the depolymerization of hemicellulose, is often considered as an extremely interesting platform molecule. Particularly, new biofuels containing molecules with 8 and 13 carbon atoms can be produced from aldol condensation of furfural and acetone followed by a deoxygenation reaction. In this work, several magnesium hydroxide fluorides MgF2-x(OH)x were prepared by a sol-gel method with various F/Mg ratios (0 to 2) at 100 °C. All solid samples were fully characterized by several techniques (nitrogen adsorption-desorption, TEM, IR, XRD and ICP). MgF2-x(OH)x were mainly composed of an intimate mixture of MgF2 and Mg(OH)2-x(OCH3)x and exhibited both acid-base properties and high surface areas. From CO2 adsorption experiments, a basicity scale corresponding to basic sites with moderate strength was established: MgF1.5(OH)0.5 > MgF(OH) ～ MgF1.75(OH)0.25 > MgF0.5(OH)1.5 > Mg(OH)2 ? MgF2. It was proposed that the presence of fluorine allowed stabilization of the basic sites with moderate strength at ambient atmosphere. The aldol condensation of furfural and acetone was carried out under mild reaction conditions (50 °C, Patm) over MgF2-x(OH)x. These catalysts were involved in this reaction without using a classical activation step for basic solid catalysts, which constitutes a major advantage of energy conservation and thus, economic efficiency. The solid with a F/Mg ratio equal to 1.5 (MgF1.5(OH)0.5) exhibited the highest activity, the furanic dimer (1,5-di(furan-2-yl)penta-1,4-dien-3-one) being the main product. A good correlation between the catalytic activity and the basicity scale was highlighted. Based on these results, the nature of active sites was proposed: a combination of a Lewis acid site (coordinatively unsaturated metal site) in the vicinity of a basic site (hydroxyl groups of Mg(OH)2-x(OCH3)x). The effect of the furfural/acetone ratio on the catalytic properties of MgF1.5(OH)0.5 was also investigated.
- Xu, Minrui,Célérier, Stéphane,Comparot, Jean-Dominique,Rousseau, Julie,Corbet, Matthieu,Richard, Frédéric,Clacens, Jean-Marc
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p. 5793 - 5802
(2019/11/05)
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- Highly efficient Nb2O5 catalyst for aldol condensation of biomass-derived carbonyl molecules to fuel precursors
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Aldol condensation is of significant importance for the production of fuel precursors from biomass-derived chemicals and has received increasing attention. Here we report a Nb2O5 catalyst with excellent activity and stability in the aldol condensation of biomass-derived carbonyl molecules. It is found that in the aldol condensation of furfural with 4-heptanone, Nb2O5 has obviously superior activity, which is not only better than that of other common solid acid catalysts (ZrO2 and Al2O3), more importantly, but also better than that of solid base catalysts (MgO, CaO, and magnesium-aluminum hydrotalcite). The detailed characterizations by N2 sorption/desorption, NH3-TPD, Py-FTIR and DRIFTS study of acetone adsorption reveal that Nb2O5 has a strong ability to activate the C=O bond in carbonyl molecules, which helps to generate a metal enolate intermediate and undergo the nucleophilic addition to form a new C–C bond. Furthermore, the applicability of Nb2O5 to aldol condensation is extended to other biomass-derived carbonyl molecules and high yields of target fuel precursors are obtained. Finally, a multifunctional Pd/Nb2O5 catalyst is prepared and successfully used in the one-pot synthesis of liquid alkanes from biomass-derived carbonyl molecules by combining the aldol condensation with the sequential hydrodeoxygenation.
- Jing, Yaxuan,Xin, Yu,Guo, Yong,Liu, Xiaohui,Wang, Yanqin
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p. 1168 - 1177
(2019/07/09)
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- Preparation of two different crystal structures of cerous phosphate as solid acid catalysts: Their different catalytic performance in the aldol condensation reaction between furfural and acetone
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Liquid fuel intermediates can be produced via aldol condensation reactions through furan aldehydes and ketones driven from biomass. It was found that cerous phosphate (CP) with two different crystal structures (hexagonal and monoclinic structure), which was tailored by different hydrothermal temperature (120 °C for the hexagonal structure and 180 °C for the monoclinic structure) and calcination temperature (900 °C for the monoclinic structure) as a solid acid catalyst, exhibit high catalytic performance in aldol condensation between furfural and acetone. The CP with hexagonal structure gave 89.1% conversion of furfural with 42% yield of 4-(2-furyl)-3-buten-2-one (FAc) and 17.5% of yield of 1,5-di-2-furanyl-1,4-pentadien-3-one (F2Ac), much higher than CP with monoclinic structure. However, both furfural conversion and aldol product yield increased from 82.3% to 96% and from 50.5% to 68.4%, respectively, for CP with the monoclinic structure after calcination owing to the higher amount of acid of catalyst after calcination but decreased continuously for CP with hexagonal structure after calcination because of its rapidly reduced BET surface area and total pore volume. The results indicated that calcination affects significantly the physical-chemical properties of CP catalysts, which influence subsequently the catalytic performance in the aldol condensation reaction. Recycling experiments showed that the catalytic performance after five number runs for CP with monoclinic structure after calcination was acceptable but was not ideal for CP with hexagonal structure owing to its poor hydrothermal stability.
- Li, Wenzhi,Su, Mingxue,Yang, Tao,Zhang, Tingwei,Ma, Qiaozhi,Li, Song,Huang, Qifu
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p. 16919 - 16928
(2019/06/24)
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- Acid Catalysts Based on Mesoporous Aromatic Frameworks in Aldol Condensation of Furfural with Some Carbonyl Compounds
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Aldol condensation of furfural with acetone and a series of aldehydes in the presence of PAF-SO3H acid catalyst based on mesoporous aromatic frameworks was investigated. The reaction course depending on the process temperature, catalyst amount, and reactant ratio was considered for the furfural condensation with acetone as an example. The catalyst can be reused in several cycles without appreciable activity loss.
- Talanova, M. Yu.,Yarchak,Karakhanov
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p. 857 - 864
(2019/08/12)
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- A Broad-Spectrum Synthesis of Tetravinylethylenes
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The first general synthesis of compounds of the tetravinylethylene (TVE) family is reported. Ramirez-type dibromo-olefination of readily accessible penta-1,4-dien-3-ones generates 3,3-dibromo[3]dendralenes, which undergo twofold Negishi, Suzuki–Miyaura or Mizoroki–Heck reactions with a wide variety of olefinic coupling partners. This route delivers a broad range of unsymmetrically substituted tetravinylethylenes with up to three different alkenyl substituents attached to the central C=C bond. The extensive scope of the approach is demonstrated by the preparation of the first higher order oligo-alkenic through-conjugated/cross-conjugated hybrid compounds. An unsymmetrically substituted TVE is shown to undergo a domino electrocyclization–cycloaddition with high site-selectivity and diastereoselectivity, thereby demonstrating the substantial synthetic potential of substituted TVEs for controlled, rapid structural complexity generation.
- Horvath, Kelsey L.,Newton, Christopher G.,Roper, Kimberley A.,Ward, Jas S.,Sherburn, Michael S.
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supporting information
p. 4072 - 4076
(2019/03/22)
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- Di-furfural-acetone chemical product and preparation method thereof
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The invention provides a high-purity di-furfural-acetone chemical product. The high-purity di-furfural-acetone chemical product contains granular di-furfural-acetone crystals, and the purity of the di-furfural-acetone is 98 percent or above. According to the high-purity di-furfural-acetone chemical product, waste alkali liquid is recycled, so that alkali waste emission is reduced, and an environment is protected; more surprisingly, after the alkali liquid is recycled, the reaction speed is greatly accelerated; and moreover, after the reaction is finished, yellow granular di-furfural-acetone crystals are obtained, and re-crystallization is not needed, so that the yield and the purity of the di-furfural-acetone are obviously improved.
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Page/Page column 6-11
(2018/11/10)
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- Stereo- and regioselective photocycloaddition of extended alkenes using γ-cyclodextrin
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Photoexcitation of dibenzalacetones (1a-d) in homogeneous media and solid state yields a mixture of products with poor conversions. Irradiation of the reactants complexed to γ-cyclodextrin predominantly affords a single dimer (syn adduct 6) despite the possibility for several monomeric and dimeric products. High selectivity in the cavitand-mediated reaction along with the structural characterization of the inclusion complex provides insight into the supramolecular interactions that drive the self-assembly of the host-guest system.
- Kashyap, Akshay,Bokosike, Treyvon K.,Bhuvanesh, Nattamai,Pattabiraman, Mahesh
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supporting information
p. 6870 - 6875
(2018/10/17)
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- Study on thermal stabilities and symmetries of chemisorbed species formed on K-zeolites upon CO2 adsorption by TPD and in situ IR spectroscopy
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In the current study, K-zeolites with different structure, Si/Al ratio and morphology have been prepared and then characterized by different techniques including in situ IR spectroscopy upon CO2 sorption and CO2–TPD with the aim of u
- Ganjkhanlou, Yadolah,Bulánek, Roman,Kikhtyanin, Oleg,Frolich, Karel
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p. 355 - 364
(2017/11/15)
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- New porous monolithic membranes based on supported ionic liquid-like phases for oil/water separation and homogenous catalyst immobilisation
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Porous monolithic advanced functional materials based on supported ionic liquid-like phase (SILLP) systems were used for the preparation of oleophilic and hydrophobic cylindrical membranes and successfully tested as eco-friendly and safe systems for oil/water separation and for the continuous integration of catalytic and separation processes in an aqueous-organic biphasic reaction system.
- Porcar, Raúl,Nuevo, Daniel,García-Verdugo, Eduardo,Lozano, Pedro,Sanchez-Marcano, José,Burguete, M. Isabel,Luis, Santiago V.
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supporting information
p. 2385 - 2388
(2018/03/13)
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- Synthesis of Renewable Lubricant Alkanes from Biomass-Derived Platform Chemicals
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The catalytic synthesis of liquid alkanes from renewable biomass has received tremendous attention in recent years. However, bio-based platform chemicals have not to date been exploited for the synthesis of highly branched lubricant alkanes, which are currently produced by hydrocracking and hydroisomerization of long-chain n-paraffins. A selective catalytic synthetic route has been developed for the production of highly branched C23 alkanes as lubricant base oil components from biomass-derived furfural and acetone through a sequential four-step process, including aldol condensation of furfural with acetone to produce a C13 double adduct, selective hydrogenation of the adduct to a C13 ketone, followed by a second condensation of the C13 ketone with furfural to generate a C23 aldol adduct, and finally hydrodeoxygenation to give highly branched C23 alkanes in 50.6 % overall yield from furfural. This work opens a general strategy for the synthesis of high-quality lubricant alkanes from renewable biomass.
- Gu, Mengyuan,Xia, Qineng,Liu, Xiaohui,Guo, Yong,Wang, Yanqin
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p. 4102 - 4108
(2017/10/31)
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- Continuous Microflow Synthesis of Fuel Precursors from Platform Molecules Catalyzed by 1,5,7-Triazabicyclo[4.4.0]dec-5-ene
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The first continuous flow synthesis of C8-C16 alkane fuel precursors from biobased platform molecules is reported. TBD (1,5,7-triazabicyclo[4.4.0]dec-5-ene) was found to be a recyclable and highly efficient organic base catalyst for the aldol condensation of furfural with carbonyl compounds, and the selectivity of mono- or difuryl product can be easily regulated by adjusting the molar ratio of substrates. By means of flow technique, a shorter reaction time, satisfactory output, and continuous preparation are achieved under the present procedure, representing a significant advance over the corresponding batch reaction conditions.
- Shen, Tao,Tang, Jingjing,Tang, Chenglun,Wu, Jinglan,Wang, Linfeng,Zhu, Chenjie,Ying, Hanjie
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supporting information
p. 890 - 896
(2017/06/23)
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- Production of Low-Freezing-Point Highly Branched Alkanes through Michael Addition
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A new approach for the production of low-freezing-point, high-quality fuels from lignocellulose-derived molecules was developed with Michael addition as the key step. Among the investigated catalysts, CoCl2?6 H2O was found most active for the Michael addition of 2,4-pentanedione with FA (single aldol adduct of furfural and acetone, 4-(2-furanyl)-3-butene-2-one). Over CoCl2?6 H2O, a high carbon yield of C13 oxygenates (about 75 %) can be achieved under mild conditions (353 K, 20 h). After hydrodeoxygenation, low-freezing-point (4 catalyst. Furthermore, C18,23 fuel precursors could be easily synthesized through Michael addition of 2,4-pentanedione with DFA (double-condensation product of furfural and acetone) under mild conditions and the molar ratio of C18/C23 is dependent on the reaction conditions of Michael addition. After hydrodeoxygenation, high density (0.8415 g mL?1) and low-freezing-point (4 catalyst. These highly branched alkanes can be directly used as transportation fuels or additives. This work opens a new strategy for the synthesis of highly branched alkanes with low freezing point from renewable biomass.
- Jing, Yaxuan,Xia, Qineng,Liu, Xiaohui,Wang, Yanqin
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p. 4817 - 4823
(2017/12/26)
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- A catalytic aldol condensation system enables one pot conversion of biomass saccharides to biofuel intermediates
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Producing bio-intermediates from lignocellulosic biomass with minimal process steps has a far-reaching impact on the biofuel industry. We studied the metal chloride catalyzed aldol condensation of furfural with acetone under conditions compatible with the upstream polysaccharide conversions to furfurals. In situ far infrared spectroscopy (FIR) was applied to guide the screening of aldol condensation catalysts based on the distinguishing characteristics of metal chlorides in their coordination chemistries with carbonyl-containing compounds. NiCl2, CoCl2, CrCl3, VCl3, FeCl3, and CuCl2 were selected as the potential catalysts in this study. The FIR results further helped to rationalize the excellent catalytic performance of VCl3 in furfural condensation with acetone, with 94.7% yield of biofuel intermediates (C8, C13) in 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) solvent. Remarkably, addition of ethanol facilitated the acetal pathway of the condensation reaction, which dramatically increased the desired product selectivity over the furfural pathway. Most significantly, we demonstrate for the first time that VCl3 catalyzed aldol condensation in acidic medium is fully compatible with upstream polysaccharide hydrolysis to monosaccharide and the subsequent monosaccharide isomerization and dehydration to furfurals. Our preliminary results showed that a 44% yield of biofuel intermediates (C8, C13) can be obtained in one-pot conversion of xylose catalyzed by paired metal chlorides, CrCl2 and VCl3. A number of prior works have shown that the biofuel intermediates derived from the one-pot reaction of this work can be readily hydrogenated to biofuels.
- Li, Huixiang,Xu, Zhanwei,Yan, Peifang,Zhang, Z. Conrad
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p. 1751 - 1756
(2017/05/31)
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- Method for catalyzing aldol condensation reaction
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The invention relates to a method for catalyzing aldol condensation reaction, belonging to the technical field of organic catalysis and systhesis. According to the method, metal halide is used as a catalyst for catalyzing the condensation reaction of a carbonyl compound under a certain condition. The method has the advantages that the metal halide is capable of catalyzing an aldol condensation reaction system under a certain condition, so that the side reaction caused by alkaline catalysis can be avoided, the applicable substrate range is relatively wide, the yield of a product of the reaction system is high, and the catalyst and a solvent can be circularly used.
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Paragraph 0034; 0035; 0036; 0037; 0038; 0039-0042; 0049-0058
(2017/08/29)
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- Atmospheric Plasma Treated Hydrotalcite-Type Catalyst
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Abstract: This work is devoted to studying the influence of plasma treatment on catalytic properties of hydrotalcite-type catalysts. Hydrotalcite-type catalysts with Mg/Al molar ratio 3:1 were prepared by co-precipitation from mixed solution of magnesium nitrate and aluminium nitrate using mixed solution of potassium carbonate and potassium hydroxide. Nonthermal atmospheric pressure dielectric barrier discharge (DBD) under defined conditions was used for modification of these catalysts. Catalysts were studied either without treatment or after calcination or with subsequent plasma modification for both cases. Catalysts were characterized by XPS, SEM, XRD, XRF and BET techniques. Catalytic activity was tested using aldol condensation of furfural and acetone. The investigated catalysts showed different catalytic performance—the plasma treatment increased the conversion of the furfural and also the selectivity of the reaction to create the desired products. Only 4s plasma treatment lead to better results than calcination at 450 °C/6?h. The best catalytic activity was achieved in case of calcined plasma treated hydrotalcite. Graphical Abstract: [Figure not available: see fulltext.]
- Hájková,Ti?ler
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p. 374 - 382
(2017/02/18)
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- Synthesis and synergistic antifungal effects of monoketone derivatives of curcumin against fluconazole-resistant Candida spp.
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Twenty-three monoketone derivatives of curcumin were synthesized to investigate the synergy with fluconazole against fluconazole-resistant Candida spp. The minimal inhibitory concentration (MIC80) and the fractional inhibitory concentration index (FICI) of the antifungal synergist fluconazole were measured against fluconazole-resistant C. albicans, C. tropicalis and C. krusei in vitro. Most of these compounds showed good synergistic activities against C. tropicalis. Among them, compound 9 exhibited significant synergistic activities against Candida spp. SARs were also discussed. In particular, a cell growth test exhibited that a combination of 1 μg ml-1 fluconazole and 64 μg ml-1 or 128 μg ml-1 compound 9 showed the most potent fungicidal effect against C. tropicalis. The synergistic effect may be associated with the changes of the intracellular ATP content and cell membrane permeability. Our results provided a basis for future evaluation and development of these compounds as leads for therapeutics for fluconazole-resistant candidiasis.
- Zhao, Fei,Dong, Huai-Huai,Wang, Yuan-Hua,Wang, Tian-Yi,Yan, Ze-Hao,Yan, Fang,Zhang, Da-Zhi,Cao, Ying-Ying,Jin, Yong-Sheng
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p. 1093 - 1102
(2017/07/12)
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- Nanosized TiO2—A promising catalyst for the aldol condensation of furfural with acetone in biomass upgrading
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Nanosized TiO2 catalyst was successfully prepared by a simple green procedure and used in liquid phase aldol condensation of furfural with acetone, a key step in bio-fuel processing. In order to determine the effect of calcination temperature on catalytic properties of TiO2, the as-prepared TiO2 and calcined TiO2 (150–900?°C) were studied by XRD, BET, TPD-CO2/NH3, TGA/DTG and FTIR evaluation. The catalytic performance of TiO2 samples in aldol condensation of furfural with acetone was evaluated and compared with that of Mg–Al hydrotalcites and a BEA zeolite. These experiments showed that uncalcined TiO2 possessed reasonable activity in aldol condensation of furfural to acetone and resulted in commonly produced condensation products. The observed catalytic behavior of TiO2 could be competitive with that reported for other inorganic solids. The calcination of TiO2 resulted, however, in a decrease in its catalytic activity due to extensive dehydration and surface dehydroxylation as well as due to changes of textural properties resulting in a decrease in the amount of accessible active sites. Thanks to its advanced properties, nanosized TiO2 is a promising catalyst for aldol condensation of furfural with acetone and could broaden possibilities for optimizing conditions for bio-fuel production.
- Nguyen Thanh, Dong,Kikhtyanin, Oleg,Ramos, Ruben,Kothari, Maadhav,Ulbrich, Pavel,Munshi, Tasnim,Kubi?ka, David
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- Surface properties of amphiphilic carbon nanotubes and study of their applicability as basic catalysts
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Amphiphilic hybrid carbon nanotubes (CNTs) containing a hydrophobic undoped section connected to a hydrophilic N-doped segment were synthesized. These amphiphilic hybrid CNTs were characterized by elemental analysis, nitrogen physisorption (BET), thermogravimetric analysis (TGA), transmission electron microscopy (TEM), CO2 adsorption coupled with microcalorimetry and X-ray photoelectron spectroscopy (XPS). The point of zero charge (PZC) for the different materials was also determined. The presence of basic sites on the surface of N-doped nanotubes is evidenced both from the CO2 adsorption measurements and the PZC determinations. Their catalytic activity in the aldol condensation of furfural derivatives and acetone was evaluated. The results of the catalytic tests show significant specific activities (amount of reactant converted per gram of solid) when compared with strong basic solutions of NaOH. A clear correlation between the characterization data and the catalytic behavior was found. Furthermore, the selectivity values towards the two main reaction products, C8 and C13 aldol condensation adducts, are close to that of the NaOH solution. All together, these findings suggest these materials might be useful basic catalysts.
- Ramirez-Barria,Guerrero-Ruiz,Castillejos-López,Rodríguez-Ramos,Durand,Volkman,Serp
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p. 54293 - 54298
(2016/07/06)
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- Potent and Selective Inhibitors of Trypanosoma cruzi Triosephosphate Isomerase with Concomitant Inhibition of Cruzipain: Inhibition of Parasite Growth through Multitarget Activity
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Triosephosphate isomerase (TIM) is an essential Trypanosoma cruzi enzyme and one of the few validated drug targets for Chagas disease. The known inhibitors of this enzyme behave poorly or have low activity in the parasite. In this work, we used symmetrical diarylideneketones derived from structures with trypanosomicidal activity. We obtained an enzymatic inhibitor with an IC50value of 86 nm without inhibition effects on the mammalian enzyme. These molecules also affected cruzipain, another essential proteolytic enzyme of the parasite. This dual activity is important to avoid resistance problems. The compounds were studied in vitro against the epimastigote form of the parasite, and nonspecific toxicity to mammalian cells was also evaluated. As a proof of concept, three of the best derivatives were also assayed in vivo. Some of these derivatives showed higher in vitro trypanosomicidal activity than the reference drugs and were effective in protecting infected mice. In addition, these molecules could be obtained by a simple and economic green synthetic route, which is an important feature in the research and development of future drugs for neglected diseases.
- Aguilera, Elena,Varela, Javier,Birriel, Estefanía,Serna, Elva,Torres, Susana,Yaluff, Gloria,de Bilbao, Ninfa Vera,Aguirre-López, Beatriz,Cabrera, Nallely,Díaz Mazariegos, Selma,de Gómez-Puyou, Marieta Tuena,Gómez-Puyou, Armando,Pérez-Montfort, Ruy,Minini, Lucia,Merlino, Alicia,Cerecetto, Hugo,González, Mercedes,Alvarez, Guzmán
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supporting information
p. 1328 - 1338
(2016/07/20)
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- Mechanistically Inspired Route toward Hexahydro-2H-chromenes via Consecutive [4 + 2] Cycloadditions
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Utilizing two robust C-C bond-forming reactions, the Baylis-Hillman reaction and the Diels-Alder reaction, we report a highly enantio-, regio-, and diastereoselective synthesis of hexahydro-2H-chromenes via two sequential [4 + 2] cycloadditions. These tandem and formal cycloadditions have also been performed as a "one-pot" sequence to access the corresponding heterocycles constituting up to five contiguous stereocenters in excellent yields and stereoselectivity.
- Ashtekar, Kumar Dilip,Ding, Xinliang,Toma, Edmond,Sheng, Wei,Gholami, Hadi,Rahn, Christopher,Reed, Paul,Borhan, Babak
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supporting information
p. 3976 - 3979
(2016/08/30)
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- Toward understanding of the role of Lewis acidity in aldol condensation of acetone and furfural using MOF and zeolite catalysts
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The aldol condensation of furfural and acetone allow producing higher value products from simple organic compounds resulting from biomass processing. In this paper, a number of metal organic framework (MOF) materials possessing Lewis acidity were investigated as catalysts in this reaction. Experiments were carried out under batch reaction conditions in Parr stirred autoclave at 100 °C during 0-4 h. The catalytic results indicated that the aldol condensation over MOFs took place with the participation of acidic rather than basic centers. The catalytic performance of these materials exhibited could not be explained by their reported Lewis acidity. Experiments with heat-activated and re-hydrated samples showed that Br?nsted acid sites could also be present in MOFs as a consequence of interaction of metal cation with surrounding water molecules. As a consequence, the catalysts having such generated Br?nsted acidity exhibited enhanced activity in the reaction.
- Kikhtyanin, Oleg,Kubi?ka, David,?ejka, Ji?í
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p. 158 - 162
(2015/04/22)
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- Unprecedented selectivities in aldol condensation over Mg-Al hydrotalcite in a fixed bed reactor setup
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Aldol condensation of furfural with acetone (molar ratio 1:10) was carried out in a flow fixed bed setup at 50 °C using calcined hydrotalcite with Mg/Al of 3 as a catalyst. Complete conversion of furfural and stable catalyst performance was obtained during the initial 50 h on stream. This period was followed by a rapid catalyst deactivation. In contrast to previous reports, higher molecular weight products that were identified as products of successive aldol condensation of acetone with furfural were observed. Their concentration was time-dependent with a maximum formation after 10 to 30 h on stream.
- Kikhtyanin, Oleg,Hora, Luká?,Kubi?ka, David
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- Comparative study of physico-chemical properties of laboratory and industrially prepared layered double hydroxides and their behavior in aldol condensation of furfural and acetone
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In this article, properties of laboratory and industrially prepared Mg-Al layered double hydroxides (LDH) with Mg:Al molar ratios varied in the range from 2 to 4 were compared. Physico-chemical properties of the studied materials were investigated with XR
- Hora, Luk,Kikhtyanin, Oleg,apek, Libor,Bortnovskiy, Oleg,Kubika, David
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p. 221 - 230
(2015/03/14)
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- Peculiar behavior of MWW materials in aldol condensation of furfural and acetone
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MWW family of different structural types (MCM-22, MCM-49, MCM-56 and MCM-36) was used as catalysts for aldol condensation of furfural and acetone studied in a batch reactor at 100 °C, autogenous pressure and a reaction time of 0-4 h. To establish a relation between physico-chemical and catalytic properties of microporous materials, the samples were characterized by XRD, SEM, N2 adsorption, FTIR and TGA. It was found that the acidic solids possessed appreciable activity in the reaction and resulted in the formation of products of aldehyde-ketone interaction. Surprisingly, MCM-22 and MCM-49, i.e. three-dimensional materials containing internal supercages, exhibited higher activity than two MCM-36 catalysts with two-dimensional character having larger accessible external surface area due to expansion of the interlayer space by swelling and pillaring treatments. Moreover, all MWW family catalysts gave higher conversion than the large-pore zeolite BEA. Nevertheless, furfural conversion decreased rapidly for all the studied materials due to coke formation. Unexpectedly, the deactivation was found to be more severe for MCM-36 catalysts than for MCM-22 and MCM-49, which was attributed to the reaction taking place also in supercages that are protected by 10-ring channels from severe coking. In contrast the cups located on the external surface were coked rapidly. This journal is the Partner Organisations 2014.
- Kikhtyanin, Oleg,Chlubna, Pavla,Jindrova, Tereza,Kubicka, David
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p. 10628 - 10641
(2014/07/07)
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- Aldol condensation of furfural and acetone over MgAl layered double hydroxides and mixed oxides
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Liquid phase aldol condensation of furfural and acetone catalyzed by solid base catalysts (MgAl hydrotalcites and MgAl mixed oxides) has been investigated as a method to valorize short chain ketones obtainable from biomass pyrolysis for the production of higher-molecular-weight products usable as fuel components. The Mg/Al molar ratios of the investigated catalysts was varied in the range from 2 to 4 and their catalytic activity was tested at different reaction temperatures (20-100 C) using several activation methods. MgAl hydrotalcites were used either after calcination as mixed oxides or after subsequent contact with liquid water or steam as rehydrated materials. Both furfural-acetone condensation products, i.e. C8 and C13, were the desired products of aldol condensation reaction. Higher reaction temperature facilitated the dehydration step and enhanced the catalyst selectivity to both dehydrated products (C8 and C13). The best results were achieved with calcined catalyst sample having Mg/Al molar ratio equal to 3 at 100 C (>95% furfural conversion and >90% selectivity to the desired products). The selectivity to the main by-product, diacetone alcohol, did not exceed 5% in any experiment. The ex situ rehydration of the calcined samples resulted in catalysts with a significantly lower activity, except the catalyst with Mg/Al molar ratio equal to 2. On the other hand, in situ rehydration caused catalyst activity improvement only in the case of the sample with Mg/Al molar ratio 3.
- Hora, Luká?,Kelbichová, Vendula,Kikhtyanin, Oleg,Bortnovskiy, Oleg,Kubi?ka, David
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p. 138 - 147
(2014/02/14)
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- Ultrafinely dispersed Pd nanoparticles on a CN@MgO hybrid as a bifunctional catalyst for upgrading bioderived compounds
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A novel and sustainable synthesis of a Pd/CN@MgO catalyst is presented here, offering a bifunctional catalyst with high catalytic activity towards a tandem aldol condensation-hydrogenation reaction of furfural with acetone in a one-pot reactor. The incorporation of biomass based hydrophilic N-containing carbon (CN) in the catalyst provides a subtle but elegant method to control the good water dispersibility, the reaction stability, and the ultrafine dispersion of palladium particles (2.2 nm in average size) in the bifunctional catalyst Pd/CN@MgO. With such improved features, an impressive 99% furfural conversion and 95% selectivity for the hydrogenated products (saturated ketones) was obtained by using Pd/CN@MgO as a novel bifunctional catalyst in the reported tandem reaction. This catalyst design strategy and the high efficiency of the catalyst in the reported system offer potential for the preparation of bi/multifunctional catalysts and the one-pot synthesis of bioderived intermediates. the Partner Organisations 2014.
- Li, Mingming,Xu, Xuan,Gong, Yutong,Wei, Zhongzhe,Hou, Zhaoyin,Li, Haoran,Wang, Yong
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supporting information
p. 4371 - 4377
(2014/10/15)
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- Pd/NbOPO4 multifunctional catalyst for the direct production of liquid alkanes from aldol adducts of furans
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Great efforts have been made to convert renewable biomass into transportation fuels. Herein, we report the novel properties of NbO x-based catalysts in the hydrodeoxygenation of furan-derived adducts to liquid alkanes. Excellent activity and st
- Xia, Qi-Neng,Cuan, Qian,Liu, Xiao-Hui,Gong, Xue-Qing,Lu, Guan-Zhong,Wang, Yan-Qin
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supporting information
p. 9755 - 9760,6
(2015/01/16)
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- Liquid phase aldol condensation reactions with MgO-ZrO2 and shape-selective nitrogen-substituted NaY
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The aldol condensation reactions of furfural/hydroxymethylfurfural (furfurals) with acetone/propanal in water-methanol solvents were studied over the solid base catalysts MgO-ZrO2, NaY and nitrogen-substituted NaY (Nit-NaY). The reactions were conducted at 120°C and 750 psig of He in batch reactors. Nit-NaY exhibited catalytic activity for aldol condensation comparable to MgO-ZrO2 and much higher than that of NaY, indicative of the increased base strength after replacing the bridging oxygen with the lower electronegativity nitrogen over Nit-NaY. The aldol condensation of furfurals with acetone produces two different products, the monomer and the dimer. The monomer is formed from reaction of furfurals with acetone. The dimer is formed from reaction of the monomer with furfurals. MgO-ZrO2 had a higher selectivity towards dimer formation. In contrast, Nit-NaY was more selective towards the monomer product due to the cage size in the FAU structure, indicating that Nit-NaY is a shape selective base catalyst. Increasing the water concentration in the feed solution or increasing the feed concentration led to both increased catalytic activity and dimer selectivity. The Nit-NaY catalyst was not stable and lost catalytic activity when recycled due to leaching of the framework nitrogen. Different characterization techniques, including XRD, high resolution Ar adsorption isotherm, basic sites titration, CO2 TPD-MS, TGA and 29Si SP MAS NMR, were used here to characterize the fresh and spent catalysts. The results show that Nit-NaY maintains only part of the FAU-type crystal structure. Furthermore, the base strength over Nit-NaY was found to be between that of Mg2+-O 2- pair and Mg(OH)2. The reaction mechanism over Nit-NaY was discussed.
- Shen, Wenqin,Tompsett, Geoffrey A.,Hammond, Karl D.,Xing, Rong,Dogan, Fulya,Grey, Clare P.,Conner Jr., W. Curtis,Auerbach, Scott M.,Huber, George W.
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experimental part
p. 57 - 68
(2011/11/05)
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- Performance of bifunctional Pd/MxNyO (M = Mg, Ca; N = Zr, Al) catalysts for aldolization-hydrogenation of furfural-acetone mixtures
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The performance of different bi-functional Pd catalysts (supported on Mg-Zr, Mg-Al and Ca-Zr mixed oxides) for the aqueous-phase aldol-condensation of acetone and furfural was studied in this work. Experiments were carried out in a batch slurry reactor at 323-393 K. Activity trends, as well as selectivity for the formation of the different adducts (C8 and C13), were correlated with the physico-chemical properties of the materials, mainly with the distribution of acid and basic sites. In general, it was observed that the catalyst with the lowest concentration of basic sites (Pd/Ca-Zr) presents the poorest performance. By contrast, the presence of medium-strength acid sites (as the observed in the case of one the Pd/Mg-Al catalyst) seems to enhance the catalytic activity of the material. Although selectivities trends were similar for the catalysts supported on Mg-Zr and Mg-Al catalysts, the ability of the materials for catalyzing the formation of the heaviest adducts depends mainly on the total concentration of basic sites.
- Faba, Laura,Díaz, Eva,Ordó?ez, Salvador
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experimental part
p. 451 - 456
(2012/02/03)
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- A novel mesoporous Pd/cobalt aluminate bifunctional catalyst for aldol condensation and following hydrogenation
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A novel mesoporous Pd/cobalt aluminate bifunctional catalyst has been synthesized by a facile co-precipitation process and used in aldol condensation of furfural with acetone and the following hydrogenation of condensation products. This kind of bifunctional catalyst has good activity and can be recycled and regenerated easily. Crown Copyright
- Xu, Wenjie,Liu, Xiaohui,Ren, Jiawen,Zhang, Peng,Wang, Yanqin,Guo, Yanglong,Guo, Yun,Lu, Guanzhong
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experimental part
p. 721 - 726
(2010/07/06)
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- C-C bond formation reactions for biomass-derived molecules
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Biomass is used as feedstock to produce renewable fuels and chemicals. To produce petroleum-derived fuels (between 8 to 15 carbons in length) from the major building blocks of biomass, which are carbohydrates of typically 5 or 6 carbons in length, there must be a C-C bond formation from the biomass-derived molecules. Chemical routes that can be employed to create C-C bonds from biomass-derived feedstocks are provided.
- Subrahmanyam, Ayyagari V.,Thayumanavan, Sankaran,Huber, George W.
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scheme or table
p. 1158 - 1161
(2011/12/02)
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- STABLE, AQUEOUS-PHASE, BASIC CATALYSTS AND REACTIONS CATALYZED THEREBY
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A catalytic process for converting biomass-derived carbohydrates to liquid alkanes, alkenes, and/or ethers is described. The process uses combinations of self- and crossed-aldol condensation reactions, dehydration reactions, and hydrogenation reactions, over specified metal-containing catalysts, to yield alkane, alkene, and ether products from carbohydrate reactants.
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Page/Page column 15; 28
(2008/06/13)
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- Facile formation of bis(3-indolyl)methylarenes by iodine-catalyzed reaction of indole with α,α′-bis(arylmethylene)ketones and α-substituted arylmethyleneketones in dry ethanol
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Bis(3-indolyl)methylarenes are obtained in good yield by reaction of indole with α,α′-bis(arylmethylene)ketones and α-substituted arylmethyleneketones in dry ethanol using catalytic amount of molecular iodine at room temperature. A plausible mechanism for formation of these products has been suggested.
- Mallik, Asok K.,Pal, Rammohan,Mandal, Tapas K.
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p. 2056 - 2059
(2008/09/19)
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- Synthesis, topoisomerase I inhibition and structure-activity relationship study of 2,4,6-trisubstituted pyridine derivatives
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For the development of new anticancer agents, phenyl, 2-pyridyl, 2-furyl, 2-thienyl, 2-furylvinyl and 2-thienylvinyl substituted derivatives on 2,4,6-position in pyridine moiety were prepared and evaluated for their topoisomerase I inhibitory activity. Among the thirteen prepared compounds, four compounds exhibited strong topoisomerase I inhibitory activity. A structure-activity relationship study indicated that the 2-thienyl-4- furylpyridine skeleton was important for topoisomerase I inhibitory activity.
- Zhao, Long-Xuan,Moon, Yoon-Soo,Basnet, Arjun,Kim, Eun-Kyung,Jahng, Yurngdong,Park, Jae Gyu,Jeong, Tae Cheon,Cho, Won-Jea,Choi, Sang-Un,Lee, Chong Ock,Lee, Sun-Young,Lee, Chong-Soon,Lee, Eung-Seok
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p. 1333 - 1337
(2007/10/03)
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- Syntheses of 4H-thiopyran-4-one 1,1-dioxides as precursors to sulfone-containing analogues of tetracyanoquinodimethane
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Synthetic routes to the unsubstituted 4H-thiopynan-4-one 1,1-dioxide (5a), 2,6-dialkyl-substituted, 2-aryl- or 2-heteroaryl-6-alkyl-substituted, 2,6-diaryl- or diheteroaryl-substituted, and 2-heteroaryl-6-aryl-substituted 4H-thiopyran-4-one 1,1-dioxides 5b-s are described. Sodium hydrosulfide hydrate in buffered aqueous alcohol can be used as a substitute for hydrogen sulfide gas for the introduction of sulfur to methyl acrylate, to 1,5-disubstituted-1,4-pentadien-3-ones 13, or to 1,5-disubstituted-1,4-pentadiyn-3-ones 17. The double dehydrogenation of 2,3,5,6-tetrahydrothiopyran-4-one 1,1-dioxides 13 with iodine-DMSO-sulfuric acid gives thiopyran-4-one 1,1-dioxides 5 in good yield and small amounts of 1,4-pentadien-3-ones 13. 2,3,5,6-Tetrahydrothiopyran-4-one 1,1-dioxide (9) and 5,6-dihydrothiopyran-4-one 1,1-dioxide (12), which lack aryl or heteroaryl substituents, give poor yields of 4H-thiopyran-4-one 1,1-dioxide (5a) with iodine-DMSO-sulfuric acid.
- Rule,Detty,Kaeding,Sinicropi
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p. 1665 - 1673
(2007/10/02)
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- Efficient Wittig-Horner and Improved Claisen-Schmidt Synthesis of Acyclic α-Enones with a 2-Furyl or 3,4-Methylenedioxyphenyl Group at the β-Position.
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The Wittig-Horner and Claisen-Schmidt syntheses of acyclic α-enanes bearing a 2-furyl or 3,4-methylenedioxyphenyl group in the β-position have been achieved using activated barium hydroxide C-200 with good yields.The Wittig-Horner reaction in homogeneous phase is shown to be more efficient than the Claisen-Schmidt condensation under interfacial solid-liquid conditions.The 1H and the 13C megnetic parameters of compounds 5 and 6 are described.The use of 1H-13C correlation spectra helped in the unambiguous assignment of the olefinic and aromatic carbons of α-enones 5a and 6a.
- Alvarez-Ibarra, Carlos,Perez, Maria Selma Arias,Fernandez, Maria J.,Serrano, David,Sinisterra, Vicente
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p. 2674 - 2686
(2007/10/02)
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