- Three molybdophosphates based on Strandberg-type anions and Zn(ii)-H 2biim/H2O subunits: Syntheses, structures and catalytic properties
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Three new inorganic-organic hybrid compounds based on Strandberg-type anions and Zn(ii)-H2biim/H2O subunits, namely {H 4(H2biim)3}[Zn(H2biim)(H 3biim)(H2O)(HP2Mo5O 23)]2·3H2O (1), {H9(H 2biim)7}[(μ-biim){(Zn(H2O)2) 0.5(HP2Mo5O23)}2] ·7H2O (2) and {H7(H2biim) 7}[Zn(H2biim)(H2O)2(HP 2Mo5O23)][H2P2Mo 5O23]·8H2O (3) (H2biim = 2,2′-biimidazole), have been synthesized in aqueous solutions and characterized. They were also used as efficient and reusable catalysts for the protection of carbonyl compounds. Their fascinating structural features are that mono Zn(ii)-supporting biphosphopentamolybdate ({P2Mo5}) clusters exist in their crystal structures, and the nitrogen donor ligand H 2biim exhibits three different coordination modes in these three compounds, respectively: for 1, two 2,2′-biimidazole molecules, as mono- and bidentate ligands coordinate to the same Zn(ii) ion; for 2, one bi-negative tetradentate ligand μ-biim bridges two Zn(ii) ions, while for 3, one neutral bidentate H2biim ligand links one Zn(ii) ion. Most importantly, compounds 1-3 represent the first example where Strandberg-type POMs are used as acid-catalysts in an organic reaction.
- Li, Zi-Liang,Wang, Ying,Zhang, Lan-Cui,Wang, Jian-Ping,You, Wan-Sheng,Zhu, Zai-Ming
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- Self-assembly synthesis of a high-content sulfonic acid group functionalized ordered mesoporous polymer-based solid as a stable and highly active acid catalyst
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A stable and highly active ordered mesoporous polymer-based acid catalyst has been prepared via a simple surfactant templating approach and oxidation treatment. The composition and nanostructure are characterized by XRD, NMR, XPS, TEM, nitrogen sorption, elemental and chemical analysis. The sulfonic acid groups have been anchored within the well-arranged channels of the polymer-based matrix. Even with a high -SO3H group loading (up to about 27.4 wt%) on the mesoporous polymer-based material, the ordered mesostructure and high surface area (～400 m2 g-1) can be retained and the functional moieties are highly chemically accessible. With the large number of acid sites (0.93-2.38 H+ mmol g-1 determined by acid-base titration) and the hydrophobic character, the mesoporous polymer-based solid exhibits unique catalytic performance in acid-catalyzed reactions such as condensation and acetalization, not only high activity (per site yield of bisphenol-A is over 45 in the condensation of phenol and acetone) but also excellent stability. Loss in acidic loading and activity is negligible even after the catalyst is reused 20 times in the acetalization of butanediol and aldehyde. The stability is most likely attributed to the hydrophobic nature of the mesoporous polymer-based solids, which favors the diffusion of water and thereby inhibits the poisoning of acidic sites caused by water generating in the reaction. Moreover, with large mesopores, the diffusion of reactants and products can be promoted and hence the catalytic activity can be further increased.
- Wang, Wei,Zhuang, Xin,Zhao, Qingfei,Wan, Ying
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- Four Strandberg-type polyoxometalates with organophosphine centre decorated by transition metal-2,2'-bipy/H2O complexes
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Four inorganic-organic hybrid compounds composed of Strandberg-type organophosphomolybdate anion [(C6H5PO3)2Mo5O15]4? (abbreviated as (PhP)2Mo5) and transition metal (TM)?2,2'-bipy/H2O complex units, namely [(TM(H2O)(bipy))2(C6H5PO3)2Mo5O15]n (TM = Co, (1); Ni, (2)), [(Cu(bipy)2)2(C6H5PO3)2Mo5O15]?2H2O (3) and [(Zn(bipy)(μ-OH))2(Zn(bipy)2(C6H5PO3)2Mo5O15)2]?3H2O (4) (bipy = 2,2'-bipyridine), were successfully constructed under hydrothermal conditions, and their structures were determined by single crystal X-ray diffraction analysis and spectroscopic methods. The central heteroatoms in these polyoxometalates (POMs) are all organophosphine (RP) groups. Compound 1 and compound 2 are isostructural (PhP)2Mo5-based TM-coordination polymers with the two-dimensional layer frameworks. In compound 3, the bi-supporting structure containing one (PhP)2Mo5 unit and two [Cu(bipy)2]2+ cations. For compound 4, it can be regarded as a dimer of two bi-supporting {Zn(bipy)2(PhP)2Mo5Zn(bipy)} clusters that were connected by two μ-OH groups. The acid-catalytic activities and fluorescence properties of the four hybrids have been investigated.
- Lu, Ting,Feng, Shu-Li,Zhu, Zai-Ming,Sang, Xiao-Jing,Su, Fang,Zhang, Lan-Cui
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- A new selective catalytic acetalization method promoted by microwave irradiation
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A new selective method of acetalization of aldehydes and cyclic ketones with 1,2-diols or alcohols catalyzed by iodine under microwave irradiation is reported.
- Kalita, Dipok J.,Borah, Ruli,Sarma, Jadab C.
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- Acetalization and Transacetalization Reactions Catalyzed by Ruthenium, Rhodium, and Iridium Complexes with {2-{{Bis[3-(trifluoromethyl)phenyl]phosphino}methyl}-2-methylpropane-1,3-diyl}bis[bis[3-(trifluoromethyl)phenyl]phosphine] (MeC[CH2P(m-CF3C6H4)2]3)
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The complexes [RhCl(3-n)(MeCN)n(CF3triphos)](CF3SO3)n (n = 1, 2; CF3triphos = MeC[CH2P(m-CF3C6H4)2]3) and [M(MeCN)3 (CF3triphos)](CF3SO3)n (M = Ru, n = 2; M = Ir, n = 3) are catalyst precursors for some typical acetalization and transacetalization reactions. The activity of these complexes is higher than those of the corresponding species containing the parent ligand MeC[CH2P(C6H5)2]3(Htriphos). Also the complexes [MCl3(tripod)] (tripod = Htriphos and CF3triphos) are active catalysts for the above reactions. The complex [RhCl2(MeCN)(CF3triphos)](CF3SO3) catalyzes the acetalization of benzophenone.
- Suelue, Mustafa,Venanzi, Luigi M.
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- Efficient and reusable SBA-15-immobilized Br?nsted acidic ionic liquid for the ketalization of cyclohexanone with glycol
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Ketalization of cyclohexanone with glycol has been carried out using molecular sieve SBA-15 immobilized Br?nsted acidic ionic liquid catalyst. The properties of the heterogeneous catalysts were characterized by elemental analysis, Fourier transform infrared (FT-IR) spectra, scanning electron microscopy (SEM), thermogravimetry/differential scanning calorimetry (TG/DSC), and N2 adsorption-desorption (BET). The results suggested that Br?nsted acidic ionic liquid [BSmim][HSO4] had been successfully immobilized on the surface of SBA-15 and the catalytic performance evaluation demonstrated that the catalyst BAIL@SBA-15 exhibited excellent catalytic activities in the ketalization of cyclohexanone with glycol. In addition, the effects of reaction temperature, catalyst loading, reaction time, and reactant molar ratio have also been investigated in detail, and a general reaction mechanism for the ketalization of cyclohexanone with glycol was given. The SBA-15 immobilized ionic liquid can be recovered easily and after reusing for 5 times in the ketalization reaction, the catalyst could still give satisfactory catalytic activity.
- Li, Ruiyun,Song, Heyuan,Wang, Guoqin,Chen, Jing
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- Preparation of hierarchically structured y zeolite with low Si/Al ratio and its applications in acetalization reactions
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Hierarchically structured Y zeolites were prepared by a post-synthetic strategy, where the as-made NaY zeolite was sequentially treated by a lactic acid solution and an alkaline solution containing cetyltrimethyl ammonium bromide (CTAB). Many techniques, including X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), N2 adsorption-desorption, Fourier-transform infrared spectroscopy (FT-IR), Thermogravimetric analysis (TG-DTG) and NH3 Temperature Programmed Desorption (NH3-TPD), were applied to characterize the chemical and textural properties of the samples. The results show that lactic acid pre-modification of NaY zeolite may cause on the one hand Na+ cation removal by proton exchange and on the other hand the dealumination of the zeolite framework with the formation of amorphous silicon-rich species offering nutrients for the fabrication of mesoporosity. After alkaline treatment in the presence of surfactant CTAB, mesoporosity can be successfully introduced into the NaHY zeolites with the microporous structures well preserved. Furthermore, the hierarchically structured Y zeolites exhibit much better performances in the acetalization reactions with large sized molecules involved. This could be attributed to the enhanced diffusion ability of large sized guest molecules through the combination of mesoporosity and microstructures compared with pure microporous Y zeolites.
- Jiao, Wen Qian,Fu, Wen Hua,Liang, Xiao Min,Wang, Yi Meng,He, Ming-Yuan
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- Synthesis and properties of a POM-based trinuclear copper(II) triazole framework
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A novel POM-based trinuclear copper(ii) triazole framework, namely, [H2{Cu6(trz)6(μ3-OH)2}Mo5O18]·3H2O (1) was isolated using a hydrothermal method, which displays a 3D network constructed from trinuclear copper(ii) units and triazole ligands with [Mo5O18]6- anions as templates. 1 has been identified by single crystal X-ray diffraction, elemental analysis, thermogravimetric analysis, powder X-ray diffraction and FT-IR. Magnetic studies indicate that antiferromagnetic interactions exist in 1. In addition, 1 exhibits good Lewis acid catalytic activity for the synthesis of cyclohexanone ethylene ketal with 95% conversion. The HOMO-LUMO gap (Eg) of 1 is 2.34 eV calculated using the Kubelka-Munk equation (Fhν)0.5, indicating that its forbidden bandwidth belongs to the semiconductor category. Visible-light photodegradation of RhB catalyzed by 1 was investigated, which shows high activity with an above 98% degradation rate.
- Xu, Li,Lu, Ying,Huang, Liping,Li, Xiaohui,Wang, Shuang,Zhang, Zhong,Liu, Shuxia
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- Controllable assembly, characterization and catalytic properties of a new Strandberg-type organophosphotungstate
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Using phenylphosphonic acid, simple tungstate and copper(ii) compounds as starting materials, an organic-inorganic hybrid Strandberg-type organophosphotungstate, {[(Cu(H2O)(μ-bipy))2(C6H5PO3)2W5O15]}n (bipy = 4,4′-bipyridyl) (1), was assembled successfully under hydrothermal conditions and characterized by physico-chemical and spectroscopic methods. Compound 1 represents the first example of a transition metal complex modified organophosphotungstate cluster. In the crystal structure of compound 1, the polymeric 1-D {Cu-bipy}n chains are interconnected by [(C6H5PO3)2W5O15]4- (abbreviated as {(C6H5P)2W5}) units into a 3-D framework. A hollow Keggin isopolytungstate [H2W12O40]6- ({W12})-Cu(ii) coordination polymer, {[Cu(bipy)2((μ-bipy)Cu(bipy))2(H2W12O40)]·12H2O}n (2), was obtained at different molar ratios of the starting materials and pH. The two Cu(ii) coordination polymers exhibit good acid-catalytic activity for the synthesis of cyclohexanone ethylene ketal. Their fluorescence properties were studied.
- Ma, Hong-Xin,Du, Jing,Zhu, Zai-Ming,Lu, Ting,Su, Fang,Zhang, Lan-Cui
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- Kinetic cyclohexylidenation and isopropylidenation of aldose diethyl dithioacetals
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Aldose diethyl dithioacetals react with 1.2 equivalents of 1-ethoxycyclohexene or 2-methoxypropene in N,N-dimethylformamide at 0° with p-toluenesulfonic acid as catalyst to give the five-membered ring acetal attached to the two terminal oxygen atoms as the major product in every case. In most instances, a small proportion of the terminal, six-membered ring acetal was also obtained, and in a few cases, terminal seven-membered ring acetals were also isolated. Cyclohexylidenation at room temperature gave the same products, but isopropyl-idenation at room temperature resulted in certain cases in partial rearrangement. Cyclohexylidenation reactions gave smaller proportions of the minor six- and seven-membered ring products. Structures were established from13C-n.m.r. and mass spectra. The13C-n.m.r. spectra of model cyclohexylidene derivatives were found very similar to those of isopropylidene derivatives previously studied. Two new features useful for structure determination were noted when the spectra of the precursor diols were compared with those of both types of derived acetals; the chemical shift of C-2 of a 1,3-propanediol derivative was shifted upfield by 6-9 p.p.m. on acetalation and the shifts of the diol carbon atoms attached to oxygen were affected according to the type of acetal and ring-size formed. Similar observations were made for methylene acetals.
- Grindley, T. Bruce,Cote, Christian J.P.,Wickramage, Chandra
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- Synthesis and catalytic activities of two new extended Preyssler–type tungstophosphates with different cavity centers
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Two new extended Preyssler-type polyoxometalates (POMs) constructed by Fe(III), 2,2′–biimidazole and Preyssler–type tungstophosphate anions with Na and Ag cavity centers respectively, namely {(H4biim)5H[Fe(H2biim)(H2O)2(ZP5W30O110)]·17H2O}n (Z?=?Na, compound 1; Z?=?Ag, compound 2; H2biim?=?2,2′–biimidazole), were designed and synthesized under hydrothermal conditions, and were systematically characterized by physico–chemical and spectroscopic methods. The two compounds are isostructural coordination polymers. In compound 1 or 2, there exists interesting infinite 1D chains composed of Preyssler–type [ZP5W30O110]14? (abbreviated as {ZP5W30}) polyanions bridged by Fe(III)–complex fragments, and these chains further formed 3D supramolecular frameworks via extensive hydrogen–bonding interactions. Especially for compound 2, two types of transition metals, i.e. one Ag+ ion as a center in the inner cavity and two Fe3+ ions as modified cations on the outer surface of one {ZP5W30} unit, existed in the same compound. Additionally, the electrochemical behaviors and acid catalytic activities of compounds 1 and 2 have been investigated.
- Du, Jing,Cao, Mei-Da,Zhu, Zai-Ming,Su, Fang,Zhang, Lan-Cui
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- Indium triflate mediated tandem acetalisation-acetal exchange reactions under solvent-free conditions
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Acyclic acetals and ketals undergo exchange reactions in the presence of catalytic quantities of indium(III) triflate and diols to generate the corresponding cyclic acetals and ketals in excellent yield. The protocol is rapid, employs mild conditions and can be adapted to employ solvent-free reaction conditions. We have further developed this methodology to encompass a tandem acetalisation-acetal exchange protocol which provides facile access to cyclic ketals from unreactive ketones also under very mild, solvent-free reaction conditions.
- Smith, Brendan M.,Graham, Andrew E.
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- A new hexamolybdate-based coppera€“2,2a€2-biimidazole coordination polymer serving as an acid catalyst and support for enzyme immobilization
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The hydrothermal reaction of (NH4)3[CoMo6O24H6]?·7H2O (CoMo6), CuCl2?·2H2O and 2,2a€2-biimidazole (H2biim) led to the formation of a new coordination polymer, namely poly[diaquabis(2,2a€2-biimidazole)hexa-??3-oxo-octa-??2-oxo-hexaoxodicopper(II)hexamolybdate(VI)], [Cu2Mo6O20(C6H6N4)2(H2O)2]n (Cu-Mo6O20), at pH 2a€“3. It is obvious that in the formation of crystalline Cu-Mo6O20, the original Anderson-type skeleton of heteropolymolybdate CoMo6 was broken and the new isopolyhexamolybdate Mo6O20 unit was assembled. In Cu-Mo6O20, one Mo6O20 unit connects four [Cu(H2biim)(H2O)]2+ ions in a pentacoordinate mode via four terminal O atoms, resulting in a tetra-supported structure, and each CuII ion is shared by two adjacent Mo6O20 units. Infinite one-dimensional chains are established by linkage between two adjacent Mo6O20 units and two CuII ions, and these chains are further packed into a three-dimensional framework by hydrogen bonds, ?€a€“?€ interactions and electrostatic attractions. The catalytic performance of this crystalline material used as an efficient and reusable heterogeneous acid catalyst for carbonyl-group protection is discussed. In addition, Cu-Mo6O20 was applied as a new support for enzyme (horseradish peroxidase, HRP) immobilization, forming immobilized enzyme HRP/Cu-Mo6O20. HRP/Cu-Mo6O20 showed good catalytic activity and could be reused.
- Sang, Xiao-Jing,Feng, Shu-Li,Lu, Ying,Zhang, Yue-Xian,Su, Fang,Zhang, Lan-Cui,Zhu, Zai-Ming
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- An open chain carboxyethyltin functionalized sandwich-type tungstophosphate based on a trivacant Dawson subunit: Synthesis, characterization and properties
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A Dawson sandwich-type polyoxometalate {C(NH2)3}12H4[αββα-{(Sn(C3H4O2))2Mn2(P2W15O56)2}]·22H2O (abbreviated as SnR-Mn-P2W15), functionalized by open chain carboxyethyltin groups, was first prepared in aqueous solution under conventional reaction conditions, and then structurally characterized by physicochemical and spectroscopic methods. Single crystal X-ray diffraction analysis revealed that two Mn2+ cations and two [Sn(CH2CH2COO)]2+ groups are located in the internal and external positions in the so-called equatorial region of SnR-Mn-P2W15, respectively. Intriguingly, two exposed carboxyl groups act as stretching-arm brackets, which provide a favorable structure for potential further functionalization. The electrocatalytic activity of SnR-Mn-P2W15 towards the reduction of hydrogen peroxide and nitrite was studied. Additionally, its acid catalysis and oxidation catalysis activities in organic synthesis were investigated. This journal is
- Bai, Jian-Ping,Su, Fang,Zhu, Hao-Tian,Sun, Hang,Zhang, Lan-Cui,Liu, Mei-Ying,You, Wan-Sheng,Zhu, Zai-Ming
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- Acid properties of organosiliceous hybrid materials based on pendant (fluoro)aryl-sulfonic groups through a spectroscopic study with probe molecules
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Two different heterogeneous catalysts carrying aryl-sulfonic moieties, in which the aromatic ring was either fluorinated or not, were successfully synthesized. The multi-step synthetic approaches implemented involved the synthesis of the silyl-derivative, template-free one-pot co-condensation (at low temperature and neutral pH) and tethering reaction. A multi-technique approach was implemented to characterize the hybrid organic-inorganic catalysts involving TGA, N2 physisorption analysis, FTIR spectroscopy, and ss MAS NMR (1H, 13C, 29Si) spectroscopy. Specifically, the acidity of the organosiliceous hybrid materials was studied through the adsorption of probe molecules (i.e. CO at 77 K and NH3 and TMPO at room temperature) and a combination of FTIR and ss MAS NMR spectroscopy. The catalytic activity of the two hybrids was tested in the acetal formation reaction between benzaldehyde and ethylene glycol. Preliminary results indicated superior performances for the fluoro-aryl-sulfonic acid, compared to the non-fluorinated sample. The findings hereby reported open new avenues for the design of heterogeneous sulfonic acids with superior reactivity in acid-catalyzed reactions. Moreover, through the implementation of spectroscopic studies, using probe molecules, it was possible to investigate in detail the acidic properties of hybrid organosiliceous materials.
- Erigoni, Andrea,Paul, Geo,Meazza, Marta,Hernández-Soto, María Consuelo,Miletto, Ivana,Rios, Ramon,Segarra, Candela,Marchese, Leonardo,Raja, Robert,Rey, Fernando,Gianotti, Enrica,Díaz, Urbano
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- Green efficient synthesis of ketal under catalysis of ionic liquid TTPT
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The invention discloses a method for green efficient synthesis of ketal under catalysis of ionic liquid TTPT. The method comprises the following steps: adding TTPT and a water-carrying agent into a raw material I and a raw material II, and carrying out a heating reflux reaction for 110-150 minutes, wherein R1 and R2 in formulas I and II are independently selected from a group consisting of a methyl group, an ethyl group and a phenyl group, or R1 and R2 are connected and cyclized to form a 5-to-10-membered naphthenic base; and R3 is selected from H or-OH. Compared with the prior art, the catalytic yield of the TTPT is remarkably improved, a good catalytic effect is achieved, and experimental operation is easy and convenient.
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Paragraph 0034-0036
(2021/08/07)
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- Crystallinity after decarboxylation of a metal-carboxylate framework: indestructible porosity for catalysis
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We report a curious case study of a Zr(iv)-carboxylate framework, which retains significant crystalline order after cascade thermocyclization of its linker components, and - more notably - after the crucial carboxylate links were severed by heat. Vigorous heat treatment (e.g., 450 °C and above) benzannulates the multiple alkyne groups on the linker to generate linked nanographene blocks and to afford real stability. The resultant Zr oxide/nanographene hybrid solid is stable in saturated NaOH and concentrated H3PO4, allowing a convenient anchoring of H3PO4into its porous matrix to enable size-selective heterogeneous acid catalysis. The Zr oxide components can also be removed by strong hydrofluoric acid to further enhance the surface area (up to 650 m2g?1), without collapsing the nanographene scaffold. The crystallinity order and the extensive thermal transformations were characterized by X-ray diffraction, scanning transmission electron microscopy (STEM), IR, solid state NMR and other instrumental methods.
- Cheng, Shengxian,Feng, Weijin,Gao, Wenpei,He, Jun,Hu, Jieying,Pan, Xiaoqing,Tieu, Peter,Xu, Zhengtao
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p. 11902 - 11910
(2020/09/21)
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- Facile synthesis of acetal over a supported novel Br?nsted and lewis acid ionic liquid catalyst
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A novel Br?nsted and Lewis acid ionic liquid (IL) chlorinated butyrolactam chlorozincinate (CPCl-ZnCl2) was synthesized by a hydrothermal process and characterized by Fourier transform infrared (FT-IR). The Fe-SBA-15 mesoporous materials with different Si/Fe mole ratios were prepared by direct synthesis method. The supported ionic liquid (IL/Fe-SBA-15) with various IL contents were prepared by a wet impregnation method and characterized by X-ray diffraction (XRD), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and N2 physical adsorption. The acidity was measured by FT-IR spectroscopy using pyridine as probes. The catalytic property was tested in acetalization of cyclohexanone with ethylene glycol. The results demonstrated that the IL/Fe-SBA-15 catalysts were of higher catalytic activity compared to Fe-SBA-15. Under optimal conditions, the acetalization could reach to 92.6% cyclohexanone conversion with 99.3% acetal selectivity. After 5 cycles, the cyclohexanone conversion decreased slightly. Also, the catalyst showed good catalytic property in the other acetalization of cyclohexanone and benzyl alcohol.
- Liu, Ruifeng,Dai, Liming,Zhao, Qian,Xie, Yingjie,Jiang, Tingshun
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p. 4396 - 4405
(2019/05/08)
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- Robust acidic pseudo-ionic liquid catalyst with self-separation ability for esterification and acetalization
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The novel acidic pseudo-ionic liquid catalyst with self-separation ability has been synthesized through the quaternization of triphenylphosphine and the acidification with silicotungstic acid. The pseudo-IL showed high activities for the esterification with average conversions over 90%. The pseudo-IL showed even higher activities for acetalization than traditional sulfuric acid. The homogeneous catalytic process benefited the mass transfer efficiency. The pseudo-IL separated from the reaction mixture automatically after reactions, which was superior to other IL catalysts. The high catalytic activities, easy reusability and high stability were the key properties of the novel catalyst, which hold great potential for green chemical processes.
- Shi, Yingxia,Liang, Xuezheng
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p. 1413 - 1421
(2019/05/04)
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- B-SBA-16 encaged functional tungstosilicic acid type ionic liquids to catalyze the ketal reaction
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There is special significance to composite catalysts using SBA-16 nano-cages as carriers in the acid catalysis field. A method for embedding boron atoms onto SBA-16 to increase acidic sites and enhance the acidity of the nano-cages was described. The tungstosilicic acid type ionic liquid (SWIL) was encaged into B-SBA-16 acidic nano-cages to obtain various composite catalysts. The acidic nano-cages and composite catalysts were characterized by FT-IR, TG/DSC, SAXD, BET, SEM, TEM, XPS and 1H NMR analyses. Research confirmed that boron was embedded onto the SBA-16 nano-cages in varying proportions and the obtained B-SBA-16 acidic nano-cages still maintained a high degree of pore ordering. The SWIL was successfully encapsulated into the acidic nano-cages via the immersion method. The cage-encapsulated tungstosilicic acid type ionic liquid catalysts SWIL/B(n)-SBA-16 were applied to catalyze the ketal reaction of cyclohexanone (CYC) with ethylene glycol (EG). The results showed that the conversion of CYC could reach 92.01% along with the yield of cyclohexanone ethylene glycol ketal (CGK) of 83.87% under ideal conditions. The CYC conversion was still nearly 86.86% and the CGK yield was 69.50% even after 8 times of continuous reuse.
- Xie, Yingjie,Zhao, Qian,Gao, Guofang,Jiang, Tingshun
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p. 17106 - 17116
(2019/11/26)
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- 8-Hydroxy-2-methylquinoline-modified H4SiW12O40: A reusable heterogeneous catalyst for acetal/ketal formation
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A heteropoly acid based organic hybrid heterogeneous catalyst, HMQ-STW, was prepared by combining 8-hydroxy-2-methylquinoline (HMQ) with Keggin-structured H4SiW12O40 (STW). The catalyst was characterized via elemental analysis, X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), thermogravimetric analysis (TG) and potentiometric titration analysis. The catalytic performance of the catalyst was assessed in the ketalization of ketones with glycol or 1,2-propylene glycol. Various reaction parameters, such as the glycol to cyclohexanone molar ratio, catalyst dosage, reaction temperature and time, were systematically examined. HMQ-STW exhibited a relatively high yield of corresponding ketal, with 100% selectivity under the optimized reaction conditions. Moreover, catalytic recycling tests demonstrated that the heterogeneous catalyst exhibited high potential for reusability, and it was revealed that the organic modifier HMQ plays an important role in the formation of a heterogeneous system and the improvement of structural stability. These results indicated that the HMQ-STW catalyst is a promising new type of heterogeneous acid catalyst for the ketalization of ketones.
- Liu, Li-Jun,Luan, Qing-Jie,Lu, Jing,Lv, Dong-Mei,Duan, Wen-Zeng,Wang, Xu,Gong, Shu-Wen
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p. 26180 - 26187
(2018/08/04)
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- Ketalization of ketones to 1,3-dioxolanes and concurring self-aldolization catalyzed by an amorphous, hydrophilic SiO2-SO3H catalyst under microwave irradiation
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The amorphous, mesoporous SiO2-SO3H catalyst with a surface area of 115 m2 g-1 and 1.32 mmol H+ per g was very efficient for the protonation of ketones on a 10percent (m/m) basis, and the catalyst-bound intermediates can be trapped by polyalcohols to produce ketals in high yields or suffer aldol condensations within minutes under low-power microwave irradiation. The same catalyst can easily reverse the ketalization reaction. Printed in Brazil-
- Barbosa, Sandro L.,Ottone, Myrlene,De Almeida, Mainara T.,Lage, Guilherme L.C.,Almeida, Melina A.R.,Nelson, David Lee,Dos Santos, Wallans T.P.,Clososki, Giuliano C.,Lopes, Norberto P.,Klein, Stanlei I.,Zanatta, Lucas D.
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p. 1663 - 1671
(2018/06/29)
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- Hierarchical Shell-Like ZSM-5 with Tunable Porosity Synthesized by using a Dissolution–Recrystallization Approach
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Zeolites have been widely used in various fields in industry, such as catalysis, separation, and adsorption, etc. The small pore size of the micropores in the zeolite could lead to severe diffusion resistance in mass transfer. Numerous efforts have been dedicated to imposing hierarchical pore systems into zeolites by using templates or leaching methods. Here, we report the synthesis of single-crystalline hierarchical shell-like ZSM-5 by utilizing a dissolution–recrystallization post-treatment on mesoporous ZSM-5. Tetrapropylammonium hydroxide solution was used in the post-treatment. The hierarchical porosity in the crystalline shell can be controlled by adding sodium cations into the synthesis system. The hierarchical shell-like ZSM-5 reported here shows higher catalytic activity in acetalization reactions containing bulky molecules.
- Lin, Junzhong,Cichocka, Magdalena O.,Peng, Fei,Yang, Taimin,Sun, Junliang
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p. 14974 - 14981
(2018/09/14)
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- Crystal structure, thermal decomposition mechanism and catalytic performance of hexaaquaaluminum methanesulfonate
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Hexaaquaaluminum methanesulfonate crystals, [Al(H2O)6][CH3SO3]3 were synthesized by a hydrothermal reaction of Al(OH)3 with methanesulfonic acid. Single-crystal diffraction determination revealed that Al3+ was coordinated by six water molecules in octahedral geometry, while the CH3SO3 – anion connected with Al3+ through coordinated water molecules by hydrogen bonds. The six-coordinate environment of Al was also determined by 27Al MAS NMR measurement. Thermogravimetric analysis and Fourier transform infrared spectroscopy showed that the decomposition intermediate at 265–365?°C was Al2(μ-OH)(CH3SO3)5 and the final product was amorphous Al2O3 residue with about 0.8 wt% SO3 at 520–800?°C. A pure phase of [Al(H2O)6][CH3SO3]3 was confirmed by powder X-ray diffraction analysis. Esterification of n-butyric acid with n-butanol and ketalization of cyclohexanone with glycol catalyzed by [Al(H2O)6][CH3SO3]3 and Al2(μ-OH)(CH3SO3)5, respectively, proceeded in 100% yield by continuously removing the produced water. In the case of tetrahydropyranylation of n-butanol at room temperature in dichloromethane, the catalytic activity of [Al(H2O)6][CH3SO3]3 was much lower than that of Al2(μ-OH)(CH3SO3)5. Furthermore, both [Al(H2O)6][CH3SO3]3 precursor and Al2(μ-OH)(CH3SO3)5 catalysts could be recycled.
- Wang, Rui,Li, Rongrong,Jiang, Heng,Gong, Hong,Bi, Yanfeng
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p. 1327 - 1338
(2017/04/06)
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- A bifunctional cerium phosphate catalyst for chemoselective acetalization
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Acid-base solid catalysts synthesized with structurally controlled uniform active sites can lead to unique catalysis. In this study, a CePO4 catalyst was synthesized using a hydrothermal method and found to exhibit high catalytic performance for the chemoselective acetalization of 5-hydroxymethylfurfural with alcohols, in sharp contrast to other homogeneous and heterogeneous acid and/or base catalysts. In the presence of CePO4, various combinations of carbonyl compounds and alcohols are efficiently converted into the corresponding acetal derivatives in good to excellent yields. Mechanistic studies show that CePO4 most likely acts as a bifunctional catalyst through the interaction of uniform Lewis acid and weak base sites with 5-hydroxymethylfurfural and alcohol molecules, respectively, which results in high catalytic performance.
- Kanai, Shunsuke,Nagahara, Ippei,Kita, Yusuke,Kamata, Keigo,Hara, Michikazu
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p. 3146 - 3153
(2017/04/04)
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- Synthesis process of organic synthetic intermediate cyclohexanone ethylene ketal
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The invention discloses a synthesis process of an organic synthetic intermediate cyclohexanone ethylene ketal. The process includes: taking cyclohexanone, ethylene glycol, a water-carrying agent cyclohexane, a self-made cerium modified nanoscale composite Fe2(SO4)3/Al2O3 solid acid catalyst and the like as the raw materials, and carrying out condensation reflux, vacuum distillation, magnetic stirring and other operations so as to obtain cyclohexanone ethylene ketal.
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Paragraph 0020; 0030; 0031; 0032; 0033; 0034; 0035-0092
(2017/07/21)
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- Preparation method and application of lactam-based B-L dual acidic ionic liquid
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The invention belongs to the field of inorganic chemistry, and provides a preparation method and application of lactam-based B-L dual acidic ionic liquid. A preparation process is divided into two steps of step 1, preparation of butyrolactam chloride (CPCl): in accordance with the principle of strong acid being used for preparation of weak acid, hydrochloric acid and butyrolactam react to prepare ammonium chloride salt, wherein feeding is performed according to the amount ratio of the hydrochloric acid to the butyrolactam being 1 to 1, the reaction is carried out under the condition of transferring from an ice bath to a water bath at 10 to 20 DEG C, and after washing with ether, vacuum drying is performed to obtain the product; step 2, preparation of butyrolactam chloride/zinc chloride (CPCl-ZnCl2): the introduction of zinc chloride is based on the principle of the zinc chloride being capable of being combined with chloridions, the zinc chloride reacts with butyrolactam chloride in accordance with the principle of low intensity and high frequency to obtain a B-L dual acidic ionic liquid catalyst. The catalyst prepared by the preparation method has two kinds of acidity, is acidity-adjustable, has no environmental pollution, and has an excellent catalytic effect on ketalation of cyclohexanone.
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Paragraph 0037-0038
(2018/01/19)
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- Three nuclear hyamines template synthesis and molecular sieve solid acid preparation and application
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The invention relates to a synthesis method of a novel trinuclear aromatic ring quaternary ammonium salt template agent SDAIII, a preparation method of a novel HZSM-5 molecular sieve, and an application of the molecular sieve to study of the catalytic performance in the condensation reaction between ethylene glycol and cyclohexanone after the molecular sieve is modified by chlorosulfonic acid. The novel molecular sieve has the main characteristics of high catalytic activity, good stability, large number of reuse, convenience in catalyst separation, simplicity in after-treatment and little pollution, is efficient environment-friendly solid acid, and is expected to be developed into a green catalyst commonly used in laboratories and industrial production.
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Paragraph 0038-0040
(2017/05/03)
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- Glucopyranosyl derivative and application thereof in medicines
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The invention relates to a glucopyranosyl derivative used as a sodium-dependent glucose transporter (SGLT) inhibitor, a medicinal composition containing the derivative, and an application of the derivative and the medicinal composition in medicines, and especially relates to the glucopyranosyl derivative represented by formula (I) or a pharmaceutically acceptable salt or all stereoisomers thereof, or the medicinal composition containing the derivative, and a use of the derivative and the medicinal composition in the preparation of medicines for treating diabetes and diabetes related diseases.
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-
Paragraph 0413; 0414; 0415; 0416
(2016/10/08)
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- Phosphorus promoted SO42-/TiO2 solid acid catalyst for acetalization reaction
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A novel phosphorus modifed SO42-/TiO2 catalyst was synthesized by a facile coprecipitation method, followed by calcination. The catalytic performance of this novel solid acid was evaluated by acetalization. The results showed that the phosphorus was very effcient to enhance the catalytic activity of SO42-/TiO2. The solid acid owned high activity for the acetalization with the yields over 90%. Moreover, the solid acid could be reused for six times without loss of initial catalytic activities.
- Zhong, Shaofeng,Ou, Qiongrong,Shao, Linjun
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p. 3005 - 3008
(2015/11/27)
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- Cyclopentyl methyl ether-NH4X: A novel solvent/catalyst system for low impact acetalization reactions
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Cyclopentyl methyl ether, a low impact ether forming a positive azeotrope with water, was successfully employed as a solvent in the synthesis of 1,3-dioxanes and 1,3-dioxolanes carried out under Dean-Stark conditions by the acetalization of aliphatic and aromatic aldehydes or ketones, employing ammonium salts as environmentally friendly acidic catalysts.
- Azzena, Ugo,Carraro, Massimo,Mamuye, Ashenafi Damtew,Murgia, Irene,Pisano, Luisa,Zedde, Giuseppe
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supporting information
p. 3281 - 3284
(2015/06/25)
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- Synthesis of 2-(1,4-dioxaspiro[4.5]decan-6-yl)acrylamides from 2-acetylcyclohexanone via palladium-catalysed aminocarbonylation
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6-(1-Iodovinyl)-1,4-dioxaspiro[4.5]decane, an iodoalkene obtained from 2-acetylcyclohexanone via ethylene ketal formation, hydrazone formation and iodination, was aminocarbonylated in the presence of a palladium-phosphine precatalyst. Systematic investigations revealed that 2-(1,4-dioxaspiro[4.5]decan-6-yl)acrylamides can be obtained in high yields via palladium-catalysed aminocarbonylation. The influence of the amine nucleophiles and of the reaction conditions on the isolated yields was investigated. Graphical abstract: (Chemical Equation Presented).
- Farkas, Roland,Petz, Andea,Kollár, László
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p. 1665 - 1671
(2015/09/21)
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- Driving an equilibrium acetalization to completion in the presence of water
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Formation of an acetal from a carbonyl substrate by condensation with an alcohol is a classical reversible equilibrium reaction in which the water formed must be removed to drive the reaction to completion. A new method has been developed for acetalization of carbonyl substrates by diols in the presence of water. Complexation of poly(4-styrenesulfonic acid) with poly(4-vinylpyridine) generates a catalytic membrane of polymeric acid at the interface between two parallel laminar flows in a microchannel of a microflow reactor. The catalytic membrane provides a permeable barrier between the organic layer and water-containing layer in the reaction, and permits discharge of water to the outlet of the microreactor to complete the acetalization. Condensation of a variety of carbonyl substrates with diols proceeded in the presence of water in the microflow device to give the corresponding acetals in yields of up to 97% for residence times of 19 to 38 s. the Partner Organisations 2014.
- Minakawa, Maki,Yamada, Yoichi M. A.,Uozumi, Yasuhiro
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p. 36864 - 36867
(2014/11/08)
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- Acetalization of aldehydes and ketones over H4[SiW 12O40] and H4[SiW12O 40]/SiO2
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H4[SiW12O40] (H-SiW12) is demonstrated to be able to efficiently catalyze the acetalization of aldehydes and ketones with ethylene glycol and 1,3-propanediol. Nevertheless, the possible leaching and the recycling of H-SiW12 are two major disadvantages that largely restrict its further application in industry. Moreover, H 4[SiW12O40] tends to deactivate strong proton sites due to the small surface area of 10 m2 g-1. Due to interactions with surface silanol groups, the proton sites of polyoxometalates (POMs) on SiO2 are less susceptible to deactivation. As such, immobilization of H4[SiW12O40] onto SiO 2 leads to the heterogeneous catalyst H4[SiW 12O40]/SiO2 (H-SiW12/SiO 2), which can catalyze the acetalization of aldehydes and ketones with ethylene glycol and 1,3-propanediol selectively and efficiently without the need of a drying agent. The acetalization process can proceed smoothly at a relatively low temperature under solvent-free conditions. The catalyst of H 4[SiW12O40]/SiO2 can be recycled at least ten times without an obvious decrease in its catalytic activity. As far as we know, the TONs of the H-SiW12/SiO2-catalyzed acetalization of cyclohexanone with ethylene glycol, and benzaldehyde with 1,3-propanediol are the highest reported so far.
- Zhao, Shen,Jia, Yueqing,Song, Yu-Fei
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p. 2618 - 2625
(2014/07/22)
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- MOR zeolite supported Bronsted acidic ionic liquid: An efficient and recyclable heterogeneous catalyst for ketalization
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In order to widen the application of ionic liquids as efficient and renewable heterogeneous catalysts, supported ionic liquids (SILs) have received considerable attention. A novel heterogeneous catalyst MOR zeolite supported Bronsted acidic ionic liquid (BAIL@MOR) was therefore prepared, characterized and applied in the ketalization reaction. The influences of reaction temperature, time, and catalyst loading have also been investigated in detail. Combined characterization results of XRD, FT-IR, SEM, TG-DTG and N 2 adsorption-desorption suggested that the BAIL [CPES-BSIM][HSO 4] was successfully immobilized on the surface of MOR zeolite by covalent bonds. Moreover, the catalytic performance tests demonstrated that the catalyst BAIL@MOR exhibited excellent catalytic activities in the ketalization of cyclohexanone with glycol, 1,2-propylene glycol and 1,3-butylene glycol under mild reaction conditions, as comparable with the homogeneous catalysis of the precursors [BSmim][HSO4] and H2SO4. In addition, the catalyst BAIL@MOR was also found to be reusable five times without a significant loss of its catalytic activity. Thus, the heterogeneous catalyst BAIL@MOR can act as a promising candidate for the ketalization reaction.
- Li, Zhang-Min,Zhou, Yan,Tao, Duan-Jian,Huang, Wei,Chen, Xiang-Shu,Yang, Zhen
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p. 12160 - 12167
(2014/03/21)
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- SUBSTITUTED XANTHINES AND METHODS OF USE THEREOF
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Compounds, compositions and methods are described for inhibiting the TRPC5 ion channel and disorders related to TRPC5.
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Page/Page column 396; 397
(2014/09/29)
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- Syntheses, structures, and catalytic activities of copper(I) complexes with the ligand 2(4,5-diphenyl-1H-imidazol-2-yl)pyridine
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Two copper(I) complexes of compositions [Cu(HL)I]2·EtOH (1) and [Cu(HL)3]I·MeOH (2) were synthesized via the reactions of HL [HL = 2(4,5-diphenyl-1H-imidazol-2-yl)pyridine] and CuI in EtOH and MeOH, respectively, under solvothermal conditions. The complexes were characterized by X-ray single crystal diffraction, IR spectroscopy, and elemental analysis. Compounds 1 and 2 are catalytically active towards ketalization reaction, giving various ketals under mild conditions. Copyright
- Yang, Hua,Liu, Yonglu,Hu, Dao-Dao
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p. 394 - 397
(2014/03/21)
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- Preparation of a novel solid acid catalyst with Lewis and Bronsted acid sites and its application in acetalization
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A novel melamine-formaldehyde resin (MFR) supported solid acid with Lewis and Bronsted acid sites was synthesized through the immobilization of acidic ionic liquid and cuprous ion on MFR. The scanning electron microscopy (SEM) characterization showed that addition of PEG-2000 in the synthesis of MFR could promote the formation of regular particles with diameters around 3.7 μm. The XRD pattern demonstrated that some cuprous ions were aggregated. The catalytic performance of this acid catalyst was evaluated by acetalization. The results showed that the catalytic activity of MFR with Bronsted acid could be improved by addition of Lewis acid. The solid acid was very efficient for the acetalization of carbonyl compounds and diols with moderate to excellent yields and there was no loss of catalytic activity even after being recycled for 6 runs. TUeBITAK.
- Du, Yijun,Shao, Linjun,Luo, Lingyan,Shi, Si,Qi, Chenze
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p. 157 - 163
(2014/02/14)
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- Zeolite nanofiber assemblies as acid catalysts with high activity for the acetalization of carbonyl compounds with alcohols
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Zeolite nanofiber assemblies (HNB-MOR) as efficient heterogeneous catalysts for the formation of a range of acetals in good yields. The mesoporosity of HNB-MOR benefits mass transfer, and the strong acidic sites on HNB-MOR facilitate acetalization activity. The catalyst can be reused 10 times without loss of activity.
- Liu, Taotao,Fu, Wenqian,Zheng, Xiang,Jiang, Jun,Hu, Maolin,Tang, Tiandi
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p. 18217 - 18221
(2014/05/20)
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- One-pot synthesis of ordered mesoporous zirconium oxophosphate with high thermostability and acidic properties
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A series of mesoporous zirconium oxophosphate (M-ZrPO) with different P/Zr molar ratios (0-1.25) has been prepared via a facile one-pot evaporation-induced self-assembly (EISA) strategy. After removing the structure-directing agents, the M-ZrPO with large specific surface area (160 m2 g-1), big pore volume (0.26 cm3 g-1) and narrow pore size distribution (5.64 nm) has been obtained. Small-angle X-ray diffraction (SXRD) and transmission electron microscopy (TEM) results showed that these materials had ordered mesoporous structure. With the increase of P/Zr, the textural properties of M-ZrPO could be improved. Moreover, the ordered mesostructure could be maintained even when treated at 800°C, indicating the M-ZrPO had attractive thermal stability. NH3-TPD and pyridine-IR analyses showed the presence of abundant Broensted and Lewis acid sites in the material. The M-ZrPO has been used successfully as solid acid catalyst and showed excellent performance in the ketalization reaction.
- Miao, Zhichao,Xu, Leilei,Song, Huanling,Zhao, Huahua,Chou, Lingjun
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p. 1942 - 1954
(2013/07/26)
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- Synthesis of a novel melamine-formaldehyde resin-supported ionic liquid with Bronsted acid sites and its catalytic activities
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Bronsted acidic ionic liquid immobilized on a melamine-formaldehyde resin (AIL-MFR) was synthesized through the reaction of melamine-formaldehyde resin (MFR) with 1,4-butanesulfonate. Using PEG-2000 as the additive, the MFR can be prepared in regular microspheres with an average diameter of 3.97 μm and surface area of 9.09 m2 g-1. The AIL-MFR had high acidity of 2.93 mmol g-1, mainly from the sulfonic groups. The catalysis results showed that the AIL-MFR had high activity and stability for acetalization with excellent conversions and yields for most substrates. Furthermore, immobilization of the acidic ionic liquid on the MFR made the recycling of the catalyst convenient.
- Xing, Guiying
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p. 1369 - 1374
(2013/10/01)
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- Synthesis of novel solid acidic ionic liquid polymer and its catalytic activities
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The novel solid acidic ionic liquid polymer has been synthesized through the copolymerization of acidic ionic liquid oligomers and resorcinol- formaldehyde (RF resin). The catalytic activities were investigated through the acetalization. The results showed that the PIL was very efficient for the reactions with the average yield over 99.0%. The procedure was quite simple with just one-step to complete both the reactions. The high hydrophobic BET surface, high catalytic activities and high stability gave the PIL great potential for green chemical processes. Pleiades Publishing, Ltd., 2013.
- Liang, Xuezheng
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p. 724 - 729
(2014/01/23)
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- Indium(III) triflate catalysed transacetalisation reactions of diols and triols under solvent-free conditions
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Acyclic acetals and ketals undergo transacetalisation in the presence of catalytic quantities of indium(III) triflate (In(OTf)3) and diols or triols under solvent-free conditions to generate the corresponding cyclic acetals and ketals in excellent yield. The methodology has been further developed to encompass a tandem acetalisation-acetal exchange protocol, which provides a facile and high yielding route to cyclic ketals from unreactive ketones under very mild reaction conditions.
- Smith, Brendan M.,Kubczyk, Tomasz M.,Graham, Andrew E.
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experimental part
p. 7775 - 7781
(2012/09/21)
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- Three-dimensional phosphine metal-organic frameworks assembled from Cu(I) and pyridyl diphosphine
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Metal-organic frameworks (MOFs) with phosphine based ligands are extremely attractive for catalysis. In this paper, phosphine has been successfully incorporated for the first time into three-dimensional (3D) MOFs. The MOFs are based on rigid L2M2 dimeric secondary building blocks assembled from Cu(I) and a pyridyl diphosphine ligand, 4-(3,5- bis(diphenylphosphino)phenyl)pyridine, with Br- (CuL-Br), Cl - (CuL-Br), or PF6- (CuL-PF6) as counteranions. The structures have a 4.122 net topology, which can be further simplified to 64.82-qtz. The MOFs contain 1D homochiral channels. The PF6- anions hosted in the 1D channel of CuL-PF6 can be readily exchanged with Br- or Cl- while keeping the framework intact. The materials show anion-tunable flexible porosity. CuL-Br reveals gradual uptake of MeOH, while CuL-PF6 exhibits stepwise sorption for MeOH. The heterogeneous Lewis acid catalytic activity of the MOFs has been shown in ketalization reaction. CuL-Br and CuL-PF6 are active in the reactions between ethylene glycol and 2-butanone/cyclohexanone, up to 93% yield with 0.2 mol % catalyst loading. In contrast, no reaction happens between ethylene glycol and bulky benzophenone, suggesting profound size selectivity. The catalysts can be reused with the framework left intact for three runs without loss of activity.
- Tan, Xin,Li, Lei,Zhang, Jianyong,Han, Xiaorui,Jiang, Long,Li, Fuwei,Su, Cheng-Yong
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experimental part
p. 480 - 485
(2012/06/16)
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- Sulfonic groups functionalized preoxidated polyacrylonitrile nanofibers and its catalytic applications
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A SO3H-bearing nanofiber mat was synthesized and investigated as a novel heterogeneous acid catalyst. Preoxidated polyacrylonitrile nanofiber mat was prepared via electrospinning and heat treatment, and then reacted with chlorosulfuric acid to introduce the sulfonic groups. The nanofiber mat owned high acidity of 2.99 mmol/g. The preoxidation and sulfonation were examined by FT-IR spectroscopy, elemental analysis and X-ray diffraction spectroscopy (XRD). The fiber morphologies were characterized by scanning electron microscopy (SEM). The catalytic activities and reuse of the prepared nanofiber mat solid acid catalyst have been evaluated for the acetalization and esterification. The regular fiber mat structure could significantly facilitate the recovery and reuse of the catalyst. The excellent catalytic performance and easy recycling made the novel fiber mat solid acid hold great potential for the green chemical processes.
- Shao, Linjun,Xing, Guiying,He, Luyao,Chen, Ji,Xie, Hangqing,Liang, Xuezheng,Qi, Chenze
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p. 133 - 137
(2015/04/15)
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- Polyacrylonitrile fiber mat supported solid acid catalyst for acetalization
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A novel polyacrylonitrile hybrid fiber mat supported solid acid catalyst was prepared by electrospin-ning, and its catalytic activities were carefully investigated through acetalization reactions. The results showed that this hybrid fiber mat exhibits high activity for the reactions, with average yields over 95%. Besides having catalytic activities similar to the solid acid, the heterogeneous solid acid/polyacrylonitrile mat can be reused in six runs without significant loss of catalytic activities. The large size of the hybrid fiber mat greatly facilitates recovery of the catalyst from the reaction mixture. The high and stable catalytic activities of the hybrid fiber mat hold great potential for green chemical processes and preparation of membrane reactors in the future.
- Shao, Linjun,Du, Yijun,Xing, Guiying,Lv, Weixi,Liang, Xuezheng,Qi, Chenze
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experimental part
p. 1199 - 1203
(2012/10/07)
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- A mild, room-temperature protection of ketones and aldehydes as 1,3-dioxolanes under basic conditions
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Protection of ketones or aldehydes as 1,3-dioxolane derivatives proceeds within minutes at room temperature in the presence of N- hydroxybenzenesulfonamide, its O-benzyl derivative, or the tosyl analogue, in the absence of strong protonic acids, and in the presence of base (Et). Acid-sensitive groups such as O-THP, O-TBS, or N-Boc are unaffected. Copyright
- Hassner, Alfred,Bandi, Chennakesava Reddy,Panchgalle, Sharad
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p. 2773 - 2776
(2013/02/21)
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- Synthesis of a novel multi-SO3H functionalized ionic liquid and its catalytic activities
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A novel multi-SO3H functionalized ionic liquid is synthesized and a detailed account of its cata- lytic activities in acetalization and acetylation is given. The results showed that the ionic liquid is very efficient in the conventional acid-catalyzed reactions with good to excellent yields within a short reaction time. Oper- ational simplicity, small amounts required, low cost of the catalyst, high yields, scalability and reusability are the key features of this methodology, which indicates the high potentialities of the novel ionic liquid to be used in environmentally friendly processes. Pleiades Publishing, Ltd., 2012.
- Xudong, Sun,Huiquan, Xiao,Yijun, Du,Jingjing, Zhang,Xuezheng, Liang,Chenze, Qi
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p. 301 - 305
(2012/10/29)
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- Nanosized sulfated zinc ferrite as catalyst for the synthesis of nopol and other fine chemicals
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A nanosized highly ordered mesoporous zinc ferrite (ZnFe2O 4; ZF) was synthesized via co-precipitation method, further sulfated with ammonium sulfate solution to obtain sulfated ZF (SZF) and have been used for the synthesis of nopol by Prins condensation of β-pinene and paraformaldehyde. The NH3-TPD and pyridine sorption DRIFT-IR studies revealed the significant enhancement in Lewis acidic sites of the zinc ferrite on sulfatation. The influence of various reaction parameters such as reaction temperature, effect of substrate stoichiometry and catalyst loading has been investigated. It gave 70% conversion of β-pinene with 88% selectivity to nopol. The spent catalyst was regenerated and reused successfully up to four cycles with slight loss in catalytic activity. The nanosized SZF catalyst was found to be highly active towards several other commercially important acid catalyzed reactions such as isomerization, acetalization and aldol condensation.
- Jadhav, Sumit V.,Jinka, Krishna Mohan,Bajaj, Hari C.
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-
- Dry gel conversion method for the synthesis of organic-inorganic hybrid MOR zeolites with modifiable catalytic activities
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Dry gel conversion (DGC) technique is first applied in the synthesis of organic-inorganic hybrid aluminosilicate zeolites. By using the DGC method, methylene-bridged organic-inorganic hybrid zeolites with an MOR topology are synthesized without organic additive, which are structurally characterized by powder XRD, FTIR, solid-state 29Si, 13C, 27Al MAS NMR, SEM, elemental analysis, XRF, XPS, and N2 adsorption techniques. This work first reports that thus-synthesized methylene-bridged hybrid zeolites can be successfully bestowed with excellent catalytic activities through different modification treatments. Co2+-exchanged hybrid zeolites are applied in the epoxidation of alkenes with air to achieve good conversions and selectivities. Especially, methylene-bridged hybrid zeolites can be sulfonated with fuming sulfuric acid to form acidic MOR-SO3H catalyst, which exhibits highly catalytic activity for the acid-catalyzed condensation reaction of cyclohexanone and glycol. This method will be one potential route for the fabrication of organic-inorganic hybrid zeolite or related molecular sieve catalysts.
- Zhou, Dan,Lu, Xinhuan,Xu, Jun,Yu, Anan,Li, Jiyang,Deng, Feng,Xia, Qinghua
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p. 4160 - 4165
(2013/01/15)
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- Rh(I)-catalyzed cyclocarbonylation of enynes with glyceraldehyde: An available carbonyl source derived from sugar alcohols
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Catalytic cyclocarbonylation reactions using a glyceraldehyde derivative as a carbonyl source are described. The rhodium(I)-catalyzed reaction of enynes with glyceraldehyde acetonide gave bicyclic cyclopentenones as the products. This presents an interesting use of a sugar alcohol derived carbon resource as well as a convenient procedure for the cyclocarbonylation of enynes. Georg Thieme Verlag Stuttgart · New York.
- Ikeda, Keiichi,Morimoto, Tsumoru,Tsumagari, Takayuki,Tanimoto, Hiroki,Nishiyama, Yasuhiro,Kakiuchi, Kiyomi
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scheme or table
p. 393 - 396
(2012/03/27)
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- Synthesis of a novel ionic liquid with both Lewis and Br?nsted acid sites and its catalytic activities
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The novel ionic liquid with both Lewis and Br?nsted acid sites has been synthesized and its catalytic activities for acetalization and Michael addition were investigated carefully. The novel ionic liquid was stable to water and could be used in aqueous solution. Furthermore, the molar ratio of the Lewis and Br?nsted acid sites could be adjusted according to different reactions. The results showed that the novel ionic liquid was very efficient for the traditional acid-catalyzed reactions with good to excellent yields in short time.
- Liang, Xuezheng,Qi, Chenze
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experimental part
p. 808 - 812
(2012/01/04)
-
