177-10-6Relevant articles and documents
Three molybdophosphates based on Strandberg-type anions and Zn(ii)-H 2biim/H2O subunits: Syntheses, structures and catalytic properties
Li, Zi-Liang,Wang, Ying,Zhang, Lan-Cui,Wang, Jian-Ping,You, Wan-Sheng,Zhu, Zai-Ming
, p. 5840 - 5846 (2014)
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.
Self-assembly synthesis of a high-content sulfonic acid group functionalized ordered mesoporous polymer-based solid as a stable and highly active acid catalyst
Wang, Wei,Zhuang, Xin,Zhao, Qingfei,Wan, Ying
, p. 15874 - 15886 (2012)
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.
Four Strandberg-type polyoxometalates with organophosphine centre decorated by transition metal-2,2'-bipy/H2O complexes
Lu, Ting,Feng, Shu-Li,Zhu, Zai-Ming,Sang, Xiao-Jing,Su, Fang,Zhang, Lan-Cui
, p. 52 - 57 (2017)
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.
A new selective catalytic acetalization method promoted by microwave irradiation
Kalita, Dipok J.,Borah, Ruli,Sarma, Jadab C.
, p. 4573 - 4574 (1998)
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.
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)
Suelue, Mustafa,Venanzi, Luigi M.
, p. 898 - 907 (2001)
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.
Efficient and reusable SBA-15-immobilized Br?nsted acidic ionic liquid for the ketalization of cyclohexanone with glycol
Li, Ruiyun,Song, Heyuan,Wang, Guoqin,Chen, Jing
, p. 7179 - 7185 (2018)
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.
Preparation of hierarchically structured y zeolite with low Si/Al ratio and its applications in acetalization reactions
Jiao, Wen Qian,Fu, Wen Hua,Liang, Xiao Min,Wang, Yi Meng,He, Ming-Yuan
, p. 58596 - 58607 (2014)
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.
Synthesis and properties of a POM-based trinuclear copper(II) triazole framework
Xu, Li,Lu, Ying,Huang, Liping,Li, Xiaohui,Wang, Shuang,Zhang, Zhong,Liu, Shuxia
, p. 2034 - 2040 (2018)
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.
Controllable assembly, characterization and catalytic properties of a new Strandberg-type organophosphotungstate
Ma, Hong-Xin,Du, Jing,Zhu, Zai-Ming,Lu, Ting,Su, Fang,Zhang, Lan-Cui
, p. 1631 - 1637 (2016)
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.
Kinetic cyclohexylidenation and isopropylidenation of aldose diethyl dithioacetals
Grindley, T. Bruce,Cote, Christian J.P.,Wickramage, Chandra
, p. 215 - 238 (1985)
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.
