Superacid Catalyst SO4^2-/ZrO2-La2O3 Prepared by Ultrasonic Co-precipitation and Low Temperature Aging

Sulfated zirconia-lanthana （SO4^2-/ZrO2-La2O3） precursors were prepared by ultrasonic coprecipitation method and followed by aging at different temperature. The precursors were treated by 0.5 mol/L H2SO4. Samples of SO4^2-/ZrO2-La2O3 nano-crystalline catalysts were obtained by baking the treated precursors at different temperatures. The acidic properties of SO4^2-/ZrO2-La2O3 were tested by the Hammett indicator method. The phase composition, specific area, particle structure, and surface state were characterized by X-ray diffraction, BET, transmission electron microscopy, infrared spectrum, and X-ray photoelectron spec- troscopy. The catalytic activities were estimated by esterification of acetic acid with glycerin. It was shown that the catalyst prepared by ultrasonic stirring and low temperature （-15 ℃） exhibited highly active sites and high catalytic property.

Benzoylation of Toluene over Alpromoted SO^(2-)_(4)/MxOy(M=Zr, Ti, Fe) Catalysts

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Preparation,characterization and catalytic properties of S_2O_8^(2-)/ZrO_2-CeO_2 solid superacid catalyst

A novel solid superacid catalyst S2O8^2-/ZrO2-CeO2 was prepared by a coprecipitation method and characterized by means of XRD FTIR, BET, TEM and DSC/TG analysis methods. The results indicated that incorporation of appropriate amounts of Ce into the catalyst was beneficial to the formation of sole tetragonal ZrO2 and effectively prevented from the formation of monoclinic ZrO〉 and restrained the loss of sulfated species. XRD revealed the presence of tetragonal Ce0.16Zr0.84O2phase in the case of S2O8^2-/ZrO2-CeO2 calcined above 500 ℃. Catalytic activities of S2O8^2-/ZrO2-CeO2 for the esterification of lactic acid with n-butanol was studied. The results showed that the optimum conditions were as follows： calcination temperature of the catalyst 600 ℃, n（lactic acid）：n（n-butyl alcohol）=1.0：3.0, w（S2O8^2-/ZrO2- CeO2）=12.0%, reaction temperature 145 ℃, and reaction time 2 h. The esterification efficiency of lactic acid was about 96.6%.

Preparation of SO_4^(2-)/TiO_2-WO_3 solid superacid and its catalytic activity in acetalation and ketaltion

SO_4^(2-)/TiO_2-WO_3 was prepared and its catalytic activity under differentsynthetic conditions was discussed with esterification of n-butanoic acid and n-butyl alcohol asprobing reaction. The optimum conditions are found that the mass fraction of H_2WO_4 used in thecompound is 12.5 percent, the calcination temperature is 580 deg C, the calcination time is 3 h, andthe soaked consistency of H_2SO_4 is 1.0 mol centre dot L^(-1). Then SO_4^(2-)/TiO_2-WO_3 wasapplied as the catalyst in the catalytic synthesis of eight similar important ketals and acetalsunder the optimum conditions and revealed high catalytic activity. On condition that the molar ratioof aldehyde/ketone to glycol is 1:1.5, the mass fraction of the catalyst used in the reactants is0.5 percent, and the reaction time is 1.0 h, the yields of ketals and acetals can reach 64.2percent-95.1 percent. Moreover, it can be easily recovered and reused.

Preparation of SO_4^(2-)/TiO_2-MoO_3 Solid Superacid and Its Catalytic Activity in Acetalation and Ketalation

SO4^2-/TiO2-MoO3, a novel solid superacid, has been prepared and its catalytic activity at different synthetic conditions was examined with esterification of n-butanoic acid and n-butyl alcohol as probing reaction.The optimum conditions were also found, that is, the mass ratio of MoO3 used in the compound is 25%, the calcination temperature 450℃, and the soaked consistency of H2SO4 is 0.5mol.L^-1. Then it was applied in the catalytic synthesis of six similar important ketals and acetals as catalyst and revealed high catalytic activity. Under the condition that the molar ratio of aldehyde/ketone to glycol was 1:1.5, the mass ratio of the catalyst to the reactants was 0.5% and the reaction time 1.0 h, the yield of ketals and acetals reached up to 63.2%. The catalyst can be easily recovered and reused.

Efficient hydrolysis of hemicellulose to furfural by novel superacid SO_4H-functionalized ionic liquids

Novel superacid SO_4H-functionalized ionic liquids(SFILs) were designed and prepared in this work. The catalytic activities of SFILs were evaluated in xylan hydrolysis and xylose dehydration to produce furfural. Combined with the results of acid strength of SFILs characterized by solid-state ^(31)P MAS NMR, it was found that the catalytic performance of SFILs was positively correlated to their acid strength. The superacid SFIL [Ch-SO_4H][CF_3SO_3] displayed the best catalytic performance with more than 80% yield of furfural, and it was also obviously superior to usual SO_3H-functionalized acidic ILs, mineral liquid acids, and acidic resin Amberlyst-15 catalysts in catalytic activity under optimized conditions. In addition, the superacid SFIL [Ch-SO_4H][CF_3SO_3] could be easily separated from reaction system and reused at least five times without obvious decrease.

Preparation of SO_4^(2-)/TiO_2-La_2O_3 solid superacid and its catalytic activities in acetalation and ketalation

SO4^2- / TiO2-La2O3, a novel solid superacid, was prepared and its catalytic activities at different synthetic conditions are discussed with esterification of n-butanoic acid and n-butyl alcohol as probing reaction. The optimum conditions have also been found, mole ratio of n（La^3＋）：n（Ti^4＋） is 1：34, the soaked consistency of H2SO4 is 0.8 tool/L, the soaked time of HESO4 is 24 h, the calcining temperature is 480 ℃, the calcining time is 3 h. Then it was applied in the catalytic synthesis often important ketals and acetals as catalyst and revealed high catalytic activity. Under these conditions on which the molar ratio of aldehyde/ketone to glycol is l： 1.5, the mass ratio of the catalyst used in the reactants is 0.5%, and the reaction time is 1.0 h, the yields of ketals and acetals can reach 41.4%-95.8%.

Enhancement of catalytic activity by homo-dispersing S_2O_8^(2–)-Fe_2O_3 nanoparticles on SBA-15 through ultrasonic adsorption

Mesoporous superacids S2O82–-Fe2O3/SBA-15(SFS)with active nanoparticles are prepared by ultrasonic adsorption method.This method is adopted to ensure a homo-dispersed nanoparticle active phase,large specific surface area and many acidic sites.Compared with bulk S2O82–-Fe2O3,Br?nsted acid catalysts and other reported catalysts,SFS with an Fe2O3 loading of 30%(SFS-30)exhibits an outstanding activity in the probe reaction of alcoholysis of styrene oxide by methanol with 100%yield.Moreover,SFS-30 also shows a more excellent catalytic performance than bulk S2O82–-Fe2O3 towards the alcoholysis of other ROHs(R=C2H5-C4H9).Lewis and Bronsted acid sites on the SFS-30 surfaces are confirmed by pyridine adsorbed infrared spectra.The highly efficient catalytic activity of SFS-30 may be attributed to the synergistic effect from the nano-effect of S2O82–-Fe2O3 nanoparticles and the mesostructure of SBA-15.Finally,SFS-30 shows a good catalytic reusability,providing an 84.1%yield after seven catalytic cycles.

Synthesis of Ethyl Oleate Catalyzed by Solid Superacid SO_4^(2-)/TiO_2/La^(3+)

Rare-earth compound solid superacid SO4^2 -/TiO2/La3＋ was prepared. Its catalytic activity was examined under different synthetic conditions for the esterification of propanoic acid and n-butyl alcohol as probing reaction. The optimum conditions were also found, which were the pH=8, the depositing time was 24 h, the mass fraction of La（NO3）3 used in solid superacid was 5%, the concentration of H2SO4 was 1.25 mol/L, the soaking time in H2SO4 was 16 h and the calcining temperature was 500℃. The ethyl oleate was synthesized from oleic acid and ethanol in the presence of SO4^2-/TiO2/La3＋. The optimum reaction conditions were obtained which were the reaction time was 6 h, molar ratio of oleic acid to ethanol was 1：4 and the mass fraction of catalyst was 4%.

Solid Superacid Catalyzed Efficient Synthesis of 2-Diethylaminoethyl Aryloxyacetates

Diethylaminoethyl aryloxyacetates are prepared efficiently in 75~95% yields bycondensation of the corresponding aryloxyacetic acids with 2-diethylaminoethanol in the presenceof catalytic amount of solid superacid SO4 /Fe2O3. 2-

Superior resistance to alkali metal potassium of vanadium-based NH_(3)-SCR catalyst promoted by the solid superacid SO_(4)^(2-)-TiO_(2)

The significant decrease of acid sites caused by alkali metal poisoning is the major factor in the deactivation of commercial V_(2)O_(5)-WO_(3)/TiO_(2)NH_(3)-SCR catalysts.In this work,the solid superacid SO_(4)^(2-)-TiO_(2) modified by sulfate radicals,was selected as the catalyst support,which showed superior potassium resistance.The physicochemical properties and K-poisoning resistance of the V_(2)O_(5)-WO_(3)/SO_(4)^(2-)-TiO_(2)(VWSTi) catalyst were carried out by XRD,BET,H2-TPR,NH3-TPD,XPS,in situ DRIFTS and TG.The results pointed out that the introduction of SO_(4)^(2-)significantly increased the NH3-SCR catalytic activity at high temperatures,with an exceptionally high NO_(x) conversion over 90% between 275℃ and 500℃.When 0.5%(mass) K_(2)O was doped on the catalysts,the catalytic performance of the traditional V_(2)O_(5)-WO_(3)/TiO_(2)(VWTi) catalyst decreased significantly,while the VWSTi catalyst could still maintain a NOxconversion over 90%in the range of 300–500℃.The characterizations suggested that the support of SO_(4)^(2-)-TiO_(2) greatly increased the number of acidic sites,thereby enhancing the adsorption capacity of the reactant NH_(3).The results above demonstrated a potential approach to achieve superior potassium resistance for NH3-SCR catalysts using solid superacid.

Preparation, Characterization of Superacid SO_4^(2-)/ZrO_2-SiO_2 and Its Activity on Catalytic Synthesis of Methyl p-Nitrobenzoate

Solid superacid SO42-/ZrO2-SiO2 was prepared by dip-impregnation method, and its catalytic activity was tested with esterification of p-nitrobenzoic acid and methanol. The optimum conditions were also found, that is, the molar ratio between silica and zirconia was 10：1, the calcination temperature was 550 ℃ and the soaked consistency of H2SO4 was 1.0 mol.L-1. Under the conditions that the ratio of methanol to aeid（mL/ g） was 12：1, the amount of catalyst was 0.5 g, the reaction time was 5 h and the stirring speed was 800 r.min-1, the yield of methyl p-nitrobenzoate could reach up to 90.5%. Then the characterizations of cataslyst, including the acidity and types of acidic centers, specific surface area and surface structure was respectively examined by Hammer indicator, in-situ pyridine IR, BET method, FT-IR（KBr）, transmission electron microscope （TEM）, and X-ray diffraction （XRD）. The results showed that the catalyst SO42-/ZrO2-SiO2 was superacid with high specific surface area due to Ho〈-12.70. It contained acidic sites of Lewis and BrФnsted, and its surface structure changed after esterification. The zirconia crystal was mainly tetragonal and silica crystal was not found.

Alkylation of Isobutane and Butene on BrФnsted-Lewis Conjugated Solid Superacids

A BrOnsted-Lewis (B-L) conjugated solid superacid HPW-SbF_5/SiO_2 wassynthesized by a two-step method. This B-L acid shows high acid strength, high activity, goodselectivity and moderate stability in alkylation of isobutane/butene due to strong interactionbetween the BrOnsted acid and the Lewis acid, as confirmed by the results of IR, NMR and XPS. Undera mild reaction condition (30℃, 15-35xl0~5 Pa), the conversion of butene was maintained at 100% for110 hours on stream and the main products were C_8 and TMP. The results of alkylation conductedunder various operating conditions indicated that the activity was improved by increasing theloading content of HPW and SbF_5. The selectivity of TMP in the products was enhanced when theisobutane/butene ratio in the feedstock was increased. The existence of some intermediates was alsoreported.

An efficient synthesis of 2,2-bis(1H-indol-3-yl)-2H-acenaphthen-1-one catalyzed by recyclable solid superacid SO_4^(2-)/TiO_2 under grinding condition

An efficient synthesis of symmetrical 2,2-bis（1H-indol-3-yl）-2H-acenaphthen-1-one is achieved via a reaction of acenaphthe-nequinone and indoles catalyzed by solid superacid SO4^2-/TiO2 under solvent-free conditions at room temperature by grinding, which provides an efficient route to the synthesis of symmetrical 2,2-bis（1H-indol-3-yl）-2H-acenaphthen-1-one.This procedure offers several advantages including solvent-free conditions,excellent yields of products,simple work-up as well as reuse of catalysts which makes it a useful and attractive protocol for the synthesis of these compounds.

Friedel-Crafts Acylation of Ferrocene Catalyzed by Solid Superacid,Silica-supported Polytrifluoromethanesulfosiloxane

Solid superacid, silica-supported polytrifluoromethanesulfosiloxane (SiO2-Si-SCF3) wasfirstly used in the Friedel-Crafts acylation of ferrocene as a novel catalyst. IR spectra, WAXD andspecific surface area of the superacid SiO2-Si-SCF3 were also investigated.

γ-Al₂O₃Supported SO₄^2&#45/ZrO₂Solid Superacid Catalysts for n-Pentane Isomerization

A solid superacid catalyst Pt-SO42-/ZrO2-A12O3 for n-pentane isomerization, was prepared by incipient-wetness impregnation. Preparetion conditions, namely, calcination temperature, concentration of sulfuric acid solution used in impregnation and Al2O3 concentration, were varied to investigate the effects on catalytic performance of Pt-SO42-/ZrO2-A12O3. The results showed that the PtSZA catalyst exhibited excellent catalytic performance for n-pentane isomerization. Under optimized preparation conditions of calcination temperature of 650°C, reaction time for 3 h, concentration of sulfuric acid solution for 0.5 mol/L, 30% of Al2O3 concentration and 0.3% of Pt concentration, the n-pentane conversion and isopentane selectivity of Pt-SO42-/ZrO2-A12O3 could reach up to 62.17% and 91.60%, respectively.

Effect of Al Content on the Isomerization Performance of Solid Superacid Pd–S_2O_8^(2-)/ZrO_2–Al_2O_3

The effect of Al content on the performance of the Pd–S2O82-/Zr O2–Al2O3solid superacid catalyst was studied using n-pentane isomerization as a probe reaction. The catalysts were also characterized by X-ray diffraction(XRD), Fourier transform Infrared(FTIR), specific surface area measurements(BET), thermogravimetry–differential thermal analysis(TG–DTA), H2-temperature programmed reduction(TPR) and NH3temperature-programmed desorption(NH3-TPD). The Pd–S2O82-/Zr O2–Al2O3catalyst made from Al2O3 mass fraction of 2.5% exhibited the best performance and its catalytic activity increased by 44.0% compared with Pd–S2O82-/Zr O2. The isopentane yield reached64.3% at a temperature of 238 °C, a reaction pressure of 2.0 MPa, a space velocity of 1.0 h-1and a H2/n-pentane molar ratio of 4.0. No obvious catalyst deactivation was observed within 100 h.

Complex Solid Superacid Catalyst WO_3-ZrO_2-SO_4^(2-) Structure of Acid Sites on the Catalyst

A new type of complex solid superacid catalyst WO_3-ZrO_2-SO_4^(2-)with an acid strength H_0≤-16.04 was prepared by kneading Zr(OH)_4 or amorphous ZrO_2 with tungstic acid(H_2WO_4)(W/Zr=0.15),followed by exposing this complex hydroxides to 0.5 tool/L H_2SO_4,calcining in air at 700～800℃ for 3h.This catalyst possesses both strong Bronsted acidity and strong Lewis acidity experimentally showed by IR observation of pyridine absorbed on it.XPS and AES techniques were employed to examine the valence states of tungsten, zirconium,sulfur and their interactions.The structure of sulfur species was studied by infrared spectroscopy and a structure model of active site was proposed upon these results.

A novel synthesis of highly active and highly stable non-noble-nickel-modified persulfated Al_(2)O_(3)@ZrO_(2) core-shell catalysts for n-pentane isomerization

The non-noble metal modified sulfated zirconia was found easy to deactivate.Herein,highly active and highly stable non-noble core-shell Ni-S_(2)O_(8)^(2−)/Al_(2)O_(3)@ZrO_(2) catalysts(Ni-SA@Z-x,x=Al content in wt%)have been successfully prepared and investigated for n-pentane isomerization.The results showed that the core-shell Ni-SA@Z-30 provided a sustained high isopentane yield(63.1%)with little or no deactivation within 5000 min at a mild reaction pressure of 2.0 MPa,which can be attributed to the following factors:(i)carbon deposition was greatly suppressed by the large pore size and huge pore volume;(ii)the loss of sulfur entities was suppressed because the small and highly dispersed tetragonal ZrO_(2) particles can bond with the S species strongly;(iii)strong Brønsted acidity can be maintained well after the isomerization.The pore structures and acid nature of the core-shell Ni-SA@Z-x are entirely different from those of the normal structure Ni-S_(2)O_(8)^(2−)/ZrO_(2)-Al_(2)O_(3),even though the Al content and the compositions of the individual components are the same.The Al_(2)O_(3)cores endow the catalysts with high internal surface area and high mechanical strength.Meanwhile,the ZrO_(2) shell,which consists of more and smaller tetragonal ZrO_(2) particles because of the large surface area of the Al_(2)O_(3)core,promotes the formation of more stable sulfur species and stronger binding sites.

Catalytic Hydrothermal Liquefaction of Algae for Production of Bio-oil with Solid Superacid Catalyst SO_(4)^(2−)/ZrO_(2)

Solid superacid SO_(4)^(2−)/ZrO_(2)as heterogeneous catalyst was prepared to upgrade the bio-oil in the progress of hydrother-mal liquefaction(HTL)for the represented algae of Chlorella vulgaris and Enteromorpha prolifera.The solid superacid catalyst could obviously adjust the composition of the bio-oil and improve the higher heating values(HHVs).The catalytic performance could be regulated by adjusting the acid amount and acid strength of SO_(4)^(2−)/ZrO_(2).Furthermore,it was explored the catalytic effects of SO_(4)^(2−)/ZrO_(2)by the HTL for algae major model components,including polysaccharides,proteins,lipids,binary mixture and ternary mixture.The results showed that the introducing of SO_(4)^(2−)/ZrO_(2)catalyst could increase the yields of bio-oil from proteins and lipids,and avoid the Maillard reaction between polysaccharides and proteins.Moreover,a possible reaction pathway and mechanisms has proposed for the formation of bio-oils from HTL of algae catalyzed by SO_(4)^(2−)/ZrO_(2)based on the systematic research of the producing bio-oil from major model components.