An Efficient Extraction-Free Method for Oxidative Desulfurization of Model Fuels Employing Cross-Linked Polyionic Liquid Phosphotungstate Catalysts

An efficient extraction-free oxidative desulfurization(ODS)process using a series of cross-linked polyionic liquid phosphotungstate(CLPIL-PW)catalysts is reported.The cross-linked PILs were prepared with DVB and 1-n-alkyl-3-vinyl imidazole hydrobromide(alkyl=ethyl,butyl,octyl,dodecyl),and were then assembled with phosphotungstic acid(H_(3)PW_(12)O_(40))to form the catalysts.The CLPIL-PWs have been applied to the oxidative removal of dibenzothiophene(DBT)from model oil with H_(2)O_(2) as an oxidant.The effects of ionic liquid(IL)cationic species,varying the DVB/IL molar ratio in the polymerization process,and varying operating conditions were investigated.The CLPIL-PWs were characterized by inductively coupled plasma(ICP)mass spectrometry,elemental analysis,scanning electron microscopy(SEM),Fourier transform infra-red(FTIR)spectroscopy,X-ray diffraction(XRD),^(13)C and^(31)P nuclear magnetic resonance(NMR)spectroscopy.The polydivinylbenzene-co-1-n-octyl-3-vinyl imidazole phosphotungstate(P(DVB-OVIm)PW)exhibited the highest DBT removal efficiency(99.9%)and remarkable recyclability,and could be reused eight times without reducing its activity.Finally,an extraction-free ODS mechanism is proposed.

Synthesis,characterization and antitumor activity of rare earth(Y,La) substituted phosphotungstates containing 5-fluorouracil

Two rare earth substituted Keggin-type phosphomngstates containing 5-fluorouracil, K10C4H4FN2O2Y（PW11O39）2· 10H2O （FYPW） and Kg（C4H4FN2O2）2La（PWl1O39）2· 18H2O （FLaPW） were synthesized in aqueous solution, and the structures were characterized by Fourier transform infrared spectroscopy （FT-IR）, element analysis, inductively coupled plasma spectrometry （ICP）, X-ray powder diffraction （XRD） and 1H nuclear magnetic resonance （NMR）. Thermal analysis showed that the decomposition processes of the two compounds could be di- vided into three steps, the loss of crystal water, the decomposition of 5-fluorouracil unit and the decomposition of Keggin-type polyanions. The in vitro cytotoxicities against HEK 293, HeLa and HepG-2 cells were studied by methyl thiazolyl tetrazolium （MTT） assay. The results showed that FYPW and FLaPW had higher antitumor activities than 5-fluorouracil, C4H4FN2O2H2PW12O40.8H2O and rare earth substituted polyoxometalates KllLn（PW11O39）2@nH2O （Ln-Y, La）. It was concluded that introducing 5-fluorouracil and rare earth （Y or La） into its structure was a considerable way to enhance antitumor activities ofpolyoxometalates.

Synthesis and antitumor activities of rare earth substituted phosphotungstates containing 5-fluorouracil

Two novel rare earth substituted phosphotungstates containing 5-fluorouracil,K 9（C 4 H 4 FN 2 O 2） 2 Nd（PW 11 O 39） 2 ·25H 2 O（FNdPW） and K 9（C 4 H 4 FN 2 O 2） 2 Ce（PW 11 O 39） 2 ·23H 2 O（FCePW）,were synthesized and characterized by elementary analysis,FT-IR spectra,X-ray powder diffraction and 1 H NMR.The thermal analysis showed that FNdPW decomposed at 210 and 493 oC,and FCePW decomposed at 223 and 471 oC,both of which had good thermal stabilities.MTT tests were performed to study the antitumor activities against HeLa cells and HepG-2 cells of FNdPW,FCePW,5-fluorouracil,C 4 H 4 FN 2 O 2 H 2 PW 12 O 40 ·8H 2 O and K 11 Ln（PW 11 O 39） 2 ·xH 2 O（Ln=Nd,Ce）,and their cytotoxicities against HEK 293 cells.The results showed that FNdPW and FCePW possessed higher antitumor activities and lower cytotoxicities than those of 5-fluorouracil and C 4 H 4 FN 2 O 2 H 2 PW 12 O 40 ·8H 2 O,of which FNdPW exhibited the highest antitumor activates against HeLa cells（EC 50 =3.41×10-6 mol/L） and HepG-2 cells（EC 50 =6.24×10-6 mol/L）.Thus the introduction of rare earth elements and 5-fluorouracil could significantly enhance antitumor effect of polyoxometalates.

THE SYNTHESIS AND STRUCTURE OF BI-VACANT D AWSON PHOSPHOTUNGSTATE K_(10)Na_2H_2P_2W_(16)O_(60)·18H_2O

The conclusion has been made that mono- and tri-vacant Dawson phosphotungstates (shown as P2W17 and P2W15)exist. The bi-vacant Dawson phosphotungstate (P2W16) which was synthesized by hydrolyzing P2W18 with Na2CO3 soluti on, has been reported by Contant et al., however this was soon rejected by themselves. It has also

Study on the Synthesis of Octyl Acetate by Phosphotungstate Heteropolyacid with Keggin Structure

1 Results Octyl Acetate is an important chemical material.It is widely used as solvent in many industries,such as plasterer,artificial leather,and lacquer varnish,spice and medicine industries.At the present time,it is prepared with acetic acid and 1-octanol in industry,by using sulfuric acid as the catalyst.This technique has many shortcomings,which include erosion of facility,many side reactions and difficulties of post-treatment.The most severe problem is its pollution to the environment[1-2],so this...

Facile synthesis of efficient pentaethylenehexamine-phosphotungstic acid heterogeneous catalysts for oxidative desulfurization

The ultra-deep desulfurization of oil needs to be solved urgently due to various problems,including environmental pollution and environmental protection requirements.Oxidative desulfurization(ODS)was considered to be the most promising technology.The facile synthesis of highly efficient and stable HPW-based heterogeneous catalysts for oxidative desulfurization is still a challenging task.In this paper,pentamethylene hexamine(PEHA)and phosphotungstic acid(HPW)were combined by a simple one-step method to prepare a heterogeneous catalyst of PEHA-HPW for the production of ultra-deep desulfurization fuel oil.The composite material exhibited excellent catalytic activity and high recyclability,which could reach a 100% dibenzothiophene(DBT)removal rate in 30 min and be recycled at least 5 times.Experiments and DFT simulations were used to better examine the ODS mechanism of PEHA-HPW.It was proved that the rich amino groups on the surface of PEHA-HPW play a crucial role.This work provides a simple and feasible way for the manufacture of efficient HPW-based catalysts.

Encapsulation of ionic liquid, phosphotungstic acid inside the nanocages of MIL-101(Cr): Effective and reusable catalyst for efficient solvent-free oxidative desulfurization from fuel oil

Oxidative desulfurization from fuel oil is one of the important methods for deep desulfurization.The development of efficient oxidative desulfurization catalysts is crucial for improving the desulfurization performance.Successful encapsulation of phosphotungstic acid(HPW)and ionic liquid(BMImBr)inside the mesoporous cages of MIL-101(Cr)was accomplished through a combination of“bottle around ship”and“ship in bottle”methods.The obtained BMImPW@MIL-101(Cr)composite was characterized by XRD,FTIR,BET,SEM,XPS and ICP methods.Results indicated that the BMImPW@MIL-101(Cr)composites with PW^(3−) loading of 23.1–50.7 wt%were obtained,demonstrating that the“bottle around ship”method is beneficial to make full use of nanocages of MIL-101(Cr)to obtain expected high loading of active PW^(3−) .The BMImPW@MIL-101(Cr)exhibits excellent reusability with no evidence of leaching of active PW^(3−) and BMIm^(+),and well-preserved structure after successive cycles of regeneration and reuse.The significantly improved stability of BMImPW@MIL-101(Cr)as compared to HPW@MIL-101(Cr)is possibly because the leaching of the active PW^(3−) −sites can be greatly suppressed by forming large size of BMImPW owing to introduction of BMIm^(+)cation.The BMImPW@MIL-101(Cr)exhibited excellent catalytic activity for solvent free oxidative desulfurization of refractory sulfides.The enhanced oxidative desulfurization activity as compared to HPW@MIL-101(Cr)can be explained by the intimate contact of sulfides with active PW^(3−) sites owing the strong attraction of BMIm^(+)cation with the sulfides.

Styrene epoxidation catalyzed by polyoxometalate/quaternary ammonium phase transfer catalysts: The effect of cation size and catalyst deactivation mechanism

Catalytic epoxidation of alkenes is an important type of organic reaction in chemical industry,and the deep insight into catalyst deactivation will help to develop new epoxidation process.In this work,series of quaternary ammoniums bearing different cationic sizes,i.e.MTOA+(methyltrioctylammonium,[(C_(8)H_(17))_(3)CH_(3)N]+),HTMA+(hexadecyltrimethylammonium,[(C_(16)H_(33))(CH_(3))_(3)N]+) and DMDOA+(dimethyldioctadecylammonium,[(C_(18)H_(37))_(2)(CH_(3))_(2)N]+) were incorporated with polyoxometalate (POM) anions to prepare phase transfer catalysts (PTCs),which were used in the styrene epoxidations.Among them,(MTOA)_(3)PW_(4)O_(24)exhibits the best catalytic performance judged from the highest styrene conversion rate(52%) and styrene oxide selectivity (93%),during which the styrene epoxidation conditions were optimized.Meanwhile,the deactivation mechanism of this kind of PTCs was proposed firstly,i.e.in the case of low H_(2)O_(2) content,the oxidant can only be used in the styrene epoxidation,in which the catalyst can transform into stable Keggin-type POM.But when the content of H_(2)O_(2) is higher,the excess H_(2)O_(2) can reactivate the Keggin-type POM into active (PW_(4)O_(24))_(3)-anions,which can trigger the ring-opening polymerization of styrene oxide.Consequently,the catalyst is deactivated by adhered poly(styrene oxide)irreversibly,which was determined by NMR spectra.In this situation,the active moiety{PO_(4)[WO(O_(2))_(2)]_(4)}_(3)-in phase-transfer catalytic system can break into some unidentified species with low W/P ratio with the presence of epoxides.This work will be beneficial for the design of new PTCs in alkene epoxidation in fine chemical industry.

Study on the epoxidation of olefins with H_(2)O_(2)catalyzed by biquaternary ammonium phosphotungstic acid

Selective epoxidation of olefins is an important field in chemical industry.In this work,we developed a new phosphotungstic acid catalyst{[(C_8H_(17))(CH_(3))_(2)N]_(2)(CH_(2))_(3)}_(1.5){PO_(4)[WO(O_(2))_(2)]_(4)}with long carbon chain and biquaternary ammonium cation.Cyclohexene could be epoxidized to cyclohexene oxide in 96.3%conversion and 98.2%selectivity.The catalyst type,solvent type,catalyst loading,initial molar ratio,temperature,cycle performance and substrate extensibility were studied and optimized,the kinetic parameters about overall reaction and unit reaction were also calculated.Dynamic light scattering analysis was carried out to explain the different catalytic performance between catalysts with different carbon chain length.This novel catalyst and the corresponding dynamics and mechanism study could probably help the industrial application on the epoxidation of cyclohexene with H_(2)O_(2).

An Organic-inorganic Hybrid Two-dimensional Bilayer Assembled from 1:2-Type[Er(α-PW11O39)2]^11–Moieties and[Cu(dap)2]^2+Linkers

A new organic-inorganic hybrid phosphotungstate-based Cu^Ⅱ-Er^Ⅲ heterometallic derivative[Cu（dap）2（H2O）][Cu（dap）2]4.5[Er（α-PW11O39）2]·4H2O（1,dap = 1,2-diaminopropane） has been hydrothermally prepared and characterized by elemental analysis,IR spectra and X-ray single-crystal diffraction.1 belongs to the triclinic space group P1 with a = 13.453（3）,b =20.137（4）,c = 24.565（4） A,α = 103.468（4）,β = 103.829（4）,γ = 98.296（4）°,V= 6148.0（19） A°3,Z =2,μ = 22.212 mm^-1,GOOF = 1.030,R = 0.0744 and wR = 0.1700.Structural analysis indicates that1 exhibits a special two-dimensional double-layer structure constructed from l：2-type[Er（α-PW11O39）2]^11- moieties and[Cu（dap）2]^2＋ linkers.From the topological viewpoint,1 displays a scare two-dimensional five-connected topology in which the[Er（α-PW11O39）2]^11- moieties function as the five-connected nodes.Furthermore,its thermogravimetric behavior has been studied.

Catalytic synthesis of acetals and ketals with H3PW12O40/PAn

A new environmental friendly catalyst H3PW12O40/PAn was prepared and identified by means of FT-IR,XRD,and TG/DTA.The optimum conditions have been found;that is,the mass ratio of PAn to H3PW12O40 is 1：1.5,the volume of methanol is 20 mL,and the reflux reaction time is 3 h.The structural identity of Keggin units is preserved after the incorporation into polyaniline matrix.Catalytic activities of H3PW12O40/PAn in synthesizing 2-methyl-2-ethoxycarbonylmethyl-1,3-dioxolane,2,4-dimethyl-2-ethoxycarbonylmethyl-1,3-dioxolane,cyclohexanone ethylene ketal,cyclohexanone 1,2-propanediol ketal,butanone ethylene ketal,butanone 1,2-propanediol ketal,2-phenyl-1,3-dioxolane,4-methyl-2-phenyl-1,3-dioxolane,2-propyl-1,3-dioxolane,and 4-methyl-2-propyl-1,3-dioxolane were reported.It has been demon-strated that H3PW12O40/PAn is an excellent catalyst.Various factors concerned in these reactions were investigated.The optimum conditions are as follows：the molar ratio of aldehyde/ketone to glycol（r） is 1：1.5,the mass ratio of the catalyst used to the reactants is 0.6%,and the reaction time is 1.0 h.Under these conditions,the yield is as follows：2-methyl-2-ethoxycarbonylmethyl-1,3-dioxolane,69.0%;2,4-dimethyl-2-ethoxycarbonylmethyl-1,3-dioxolane,79.5%;cyclohexanone ethylene ketal,78.9%;cyclohexanone 1,2-propanediol ketal,85.3%;butanone ethylene ketal,56.9%;butanone 1,2-propanediol ketal,78.1%;2-phenyl-1,3-dioxolane,76.3%;4-methyl-2-phenyl-1,3-dioxolane,94.2%;2-propyl-1,3-dioxolane,70.7%;and 4-methyl-2-propyl-1,3-dioxolane,79.2%.

Insight into the oxidative desulfurization of high-sulfur petroleum coke under mild conditions:a journey of vanadium-substituted Dawson-type phosphotungstic acid

High-sulfur petroleum coke(HSPC),that is a by-product from slag oil in the coking process of refning,shows versatility values in practical applications and,however,concentrates the majority of organic sulfur.Herein,we design and construct a highly efective CTAB@HPA composites to be explored for the catalytic oxidative desulfurization of HSPC under mild conditions using hydrogen peroxide as the oxidant and 1-butyl-3-methylimidazole tetrafuoroborate ionic liquid as the extractant.The results demonstrate that the sulfur content of HSPC could be strikingly reduced from 4.46 wt%to 2.48 wt%under 60℃ and atmospheric pressure,and that the organic sulfur in HSPC is mainly oxidized to sulfoxide,sulfone and sulfate,which latter can be directly separated from petroleum coke.Moreover,the efect of reaction conditions on the desulfurization performance of HSPC as well as the catalytic oxidation reaction kinetic of HSPC desulfurization was systematically investigated.Furthermore,a mechanism for the oxidative desulfurization of HSPC over CTAB@HPA catalysts was proposed.Therefore,this work provides new insight into how to construct active catalysts for the desulfurization of HSPC under mild conditions.

Synthesis of Bimodal Mesoporous TiO_(2)-PTA/BMMS and Its Enhanced Performance in the Photocatalytic Oxidative Desulfurization

With the bimodal mesoporous silica(BMMS)acting as the support and the composite of TiO2 with phosphotungstic acid(PTA)functioning as the active constituent,TiO_(2)-PTA/BMMS was synthesized by the two-step impregnation route.This catalyst was applied in the photocatalytic oxidative desulfurization(PODS)process,with dibenzothiophene serving as the model sulfur compound.PODS proceeds in one pot,in which H_(2)O_(2) acts as the oxidant and methanol plays the role of the solvent.TiO_(2)-PTA/BMMS was characterized by XRD,N_(2) adsorption and desorption,XRF,FTIR,UV-vis,SEM,EDS and TEM techniques.It showed that the introduction of PTA contributes higher order,higher surface area and pore volume to the bimodal mesoporous support.With TiO_(2)-PTA/BMMS used as the catalyst under the UV irradiation,the desulfurization rate can reach 99.6%.This result is obviously higher than that achieved by TiO_(2)/BMMS.The catalyst also has no significant drop in catalytic activity after eight runs of reusing.In such catalytic system,the synergistic effects of this photocatalytic oxidation and the extraction with the methanol serving as the solvent played an indispensable role.

Synergistic Effect between Zr-MOF and Phosphotungstic Acid for Oxidative Desulfurization

PTA/UiO-66 composites were successfully synthesized by the hydrothermal method.The results showed that the synergistic effect between phosphotungstic acid(PTA)and UiO-66 could enhance the oxidative desulfurization(ODS)activity.The XRD results proved that UiO-66 retained its structure in the PTA/UiO-66 composites.The SEM results showed that the PTA/UiO-66 catalysts exhibited regular octahedral shape.The Raman spectra revealed that PTA in the composites retained the Keggin structure.The XPS results showed that the electron transfer occurred from Zr-MOF to PTA.The ODS reaction mechanism was discussed.Electrons transfer from Zr-MOF to PTA can promote the generation of active species(·OH)and thus enhance the ODS activity.This explanation can be confirmed by the formation of oxygen vacancy and W0 as revealed by the XPS analysis.

Three-dimensionally Ordered Macroporous Phosphotungstic Acid/SiO2 for Efficient Catalytic Oxidative Desulfurization

Three-dimensionally ordered（3DOM） macroporous phosphotungstic acid/SiO_2（HPW/SiO_2） materials were prepared by using colloidal crystal as templates and applied for oxidative desulfurization（ODS） of the model fuel oil. The obtained HPW/SiO_2 materials were characterized through scanning electron microscopy, powder X-ray diffraction, N_2 sorption, and Fourier transform infrared spectroscopy. The results indicated that 3 DOM HPW/SiO_2 possessed hierarchical pore architectures which contained ordered macropores and disordered mesopores, with the Keggin type HPW embedded in the framework of pore structure. The removal rate of dibenzothiophene（DBT） could reach 100% under the optimum conditions, moreover. The performance was only slightly decreased for the regenerated catalyst after 7 cycles.

A phosphotungstic acid coupled silica-Nafion composite membrane with significantly enhanced ion selectivity for vanadium redox flow battery

An ultra-high ion-selective Nafion composite membrane modified by phosphotungstic acid(PWA)coupled silica for vanadium redox flow battery(VRB)was constructed and prepared through solution casting.The composite membrane exhibits excellent proton conductivity and vanadium ions blocking property by incorporating the nanohybrid composed of silica and PWA into the Nafion ionomer.Simple tuning for the filling amount of the nanohybrid endows the obtained membranes preeminent vanadium barrier property including a minimum vanadium permeability of 3.13×10-7cm2min-1and a maximum proton conductivity of 0.081 S cm-1at 25°C.These indicate an ion selectivity of 2.59×105S min cm-3,which is 6.8times higher than that of recast Nafion(0.33×105S min cm-3).As a result,the VRB with the composite membrane shows superior battery performance containing a lower self-discharge rate,higher capacity retention and more robust cyclic stability compared with recast Nafion over a range of current densities from 40 to 100 m A cm-2.

A multi-functional Ru Mo bimetallic catalyst for ultra-efficient C3 alcohols production from liquid phase hydrogenolysis of glycerol

Ru and Mo bimetallic catalysts supported on active carbon modified by phosphotungstic acid(PW)were designed and applied in glycerol hydrogenolysis reaction.The physicochemical properties of the catalysts were characterized and the presence of active sites was investigated from the perspective of the glycerol hydrogenolysis performance.The MoOxis highly selective for the C—O bond cleavage of glycerol molecules,which can reasonably regulate the strong C—C bond cleavage activity of Ru nanoparticles.By using sequential deposition of Ru and Mo supported on mesoporous PW-C,the characterization results show that the combination of isolated low-valence MoOxwith metal Ru particles can form“MoOx-Ru-PW”,which provides highly catalytic activity toward C—O bond cleavage,selectively producing more C3 alcohols(mainly 1,2(3)-propanediol).The glycerol conversion of 1%Mo/Ru/PW-C catalyst was 59.6%,the selectivity of C3 alcohol was 96.1%,and the selectivity of propanediol(1,2(3)-propanediol)was 94.9%.It is noteworthy that the selectivity of 1,3-propanediol reached 20.7%when the PW was 21.07%(mass).This study provides experimental evidence for the tandem dehydration and hydrogenation mechanism of the multifunctional Mo/Ru/PW-C catalyst.

Oxidation Reactivities of Organic Sulfur Compounds in Fuel Oil Using Immobilized Heteropoly Acid as Catalyst

Heteropoly acid of Keggin structure phosphotungstic（HPW） and phosphomolybdic（HPMo） were chemically anchored to the modified SBA-15 channel. The materials were used as catalyst for oxidative desulfurization of organic sulfur compounds including benzothiophene （BT）, dibenzothiophene （DBT） and 4,6-dimethydibenzothiophene （4,6-DMDBT）. The experimental results show that the catalysts are efficient and reusable, the catalytic activity is hardly reduced even in the 5th cycle of use.

Synthesis,Characterization and Catalytic Application of H_3PW_(12)O_(40)/MCM-48 in the Esterification of Methacrylic Acid with n-butyl Alcohol

A novel environmental friendly catalyst, H3PW12O40/MCM-48, was prepared by impregnation method. The catalysts were characterized by means of XRD and FT-IR. The synthesis of n-butyl methacrylate catalyzed by H3PW12O40/MCM-48 was studied with methacrylic acid and n-butyl alcohol as reactants. H3PW12O40/MCM-48 is an excellent catalyst for synthesizing n-butyl methacrylate and Keggin structure of H3PW12O40 kept unchanged after being impregnated on surface of the molecular sieve support. Effects of n（methacrylic acid）：n（n-butyl alcohol）, catalyst dosage, cyclohexane（water-stripped reagent） and reaction time on yields of the product were investigated. The optimum conditions have been found, that is, molar ratio of acid to alcohol is 1：1.6, mass ratio of catalyst used to the reactants is 0.5% and reaction time is 2.0 h. Under these conditions, the yield of n-butyl methacrylate can reach 93.7%.

Photocatalytic Degradation of Organic Dye Methyl Orange with Phosphotungstic Acid

Silicotungstic acid and phosphotungstic acid were prepared and characterized by Fourier Transform Infrared Spectroscopy (FTIR) and X-ray diffraction (XRD). The results showed that the prepared catalysts possess classical Keggin structure. The factors on the degradation of methyl orange, such as the kind of catalyst, the amount of catalyst, the original concentration of dye and illumination time were investigated under metal halide lamp. The degradation of methyl orange is up to 93.6% with phosphotungstic acid at the best reaction conditions at 8.89 g/L concentration of phosphotungstic acid, 5.56 mg/L concentration of methyl orange and 80 min illumination time.