Solid Superacid Research Articles

Catalytic Conversion of Cellulose to Cellulose Acetate Propionate (CAP) Over SO42-/ZrO2Solid Acid Catalyst

The solid super acid catalyst <TEX>$SO{_4}^{2-}$</TEX>/<TEX>$ZrO_2$</TEX> was prepared by impregnation method using <TEX>$ZrO_2$</TEX> as the catalyst support. Catalyst forming was taken into consideration in order to separate catalyst from the mixture of cellulose acetate propionate (CAP). <TEX>$Al_2O_3$</TEX> and sesbania gum powder were selected as binding agent and auxiliary agent respectively. The catalytic properties were evaluated through esterification of cellulose with acetic anhydride, propionic anhydride and characterized by XRD, FTIR and <TEX>$NH_3$</TEX>-TPD. In this paper, the effects of concentration of <TEX>$H_2SO_4$</TEX> impregnated, calcination temperature, esterification temperature and esterification time on the yield, acyl content and viscosity of CAP were investigated. The results showed that <TEX>$SO{_4}^{2-}/ZrO_2$</TEX> successfully catalyzed CAP synthesis over catalysts impregnated in 0.75 mol/L <TEX>$H_2SO_4$</TEX> and calcined at <TEX>$500^{\circ}C$</TEX>. The yield, acetyl content and propionyl content of CAP reached the maximum value of 105.3%, 29.9% and 25.8% reacted at <TEX>$50^{\circ}C$</TEX> for 8 h.

Regioselective Nitration of Aromatics with Nanomagnetic Solid Superacid SO42−/ZrO2‐MxOy‐Fe3O4 and Its Theoretical Studies

AbstractA series of micro‐ and nanosulfated zirconia loaded on Fe3O4 or other metal oxides (SO42−/ZrO2‐MxOy‐Fe3O4 (M=Ti4+, V5+, and Zn2+)) was prepared, characterized, and used in nitration. The nitration conditions with these solid superacids were then optimized to achieve the best regioselectivity and improve the performances of the catalysts as well. In the experimental results, SZTF (SO42−/ZrO2‐TiO2‐Fe3O4) showed excellent catalytic activity and it increased the surface area of SO42−/ZrO2 by up to 15 %. The increase not only facilitated the generation of NO2+, but also provided more opportunities for metal ions to interact with aromatic compounds. With chlorobenzene as substrate, theoretical research on its geometric parameters, electron clouds, and electron spin density was used to investigate the interaction between transition metals and chlorobenzene.

Synthesis and testing of glycerol ketals as components for diesel fuel

In the general context of replacing classical fuel with alternative fuels based on renewable raw materials, biodiesel production has increased in the last years, generating a large amount of glycerol as by-product. Therefore, it is important to find new applications for the excess of produced glycerol. This paper presents the synthesis of three oxygenated compounds, obtained from catalytic condensation of glycerol with ketones. Glycerol derivatives were prepared in very good yields using solid superacid SO42−/SnO2 as catalyst. The influence of blended ratio of oxygenated compound synthesized on the quality parameters of diesel fuel like viscosity, pour point and flash point was studied.

An overview on synthetic methods of an analogous series of cinnamates

Nowadays a lot of synthetic methods of an analogous series of cinnamates using different catalysts such as sulfonic acid ( p-toluene-sulfonic acid ), inorganic salt ( NH 4 Fe(SO 4 ) 2 ∙12H 2 O ) and solid super acid ( SO 4 2- /La 2 O 3 -ZrO 2 -HZSM-5 ) have been reviewed in the present paper. The yields of an analogous series of cinnamates are improved by the addition of above catalysts. These methods are having the advantages of simple process and low investment costs.

Study on α-Pinene Isomerization over MCM-41 Supported SO&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;2-&lt;/sup&gt;⁄TiO&lt;sub&gt;2&lt;/sub&gt;

Mesoporous MCM-41 molecular sieve was synthesized hydrothermally and selected tetraethoxysilane as silica source. Solid superacid was supported on MCM-41 by dipping and roasting. The samples were characterized by XRD, TEM, and FT-IR. Solid superacid evenly dispersed on MCM-41 with a good pore structure. Their catalytic activities were evaluated in the isomerization of α-pinene. The results show that samples had a good conversion rate and selectivity.

AN OVERVIEW ON SYNTHETIC METHODS OF ALKYL CINNAMATES

Nowadays three synthetic methods of cinnamate using different catalysts such as heteropolyacid ( H 8 SiW 12 O 42 ∙XH 2 O ) and solid super acid ( SO 4 2- /La 2 O 3 -ZrO 2 -HZSM-5 and SO 4 2- /TiO 2 ) have been reviewed in the present paper. Effects of the reaction conditions such as the microwave heating power, the microwave heating times, the amount of the catalyst, the molar ratio of cinnamic acid to alcohol and the reaction time on the yields of cinnamate have been discussed also. The yields of cinnamate are improved by the addition of above catalysts. These methods are having the advantages of simple process and low investment costs.

An overview on synthetic methods of iso-amyl benzoate

Nowadays a few of synthetic methods of iso-amyl benzoate using different catalysts such as sulfonic acid ( p-toluene-sulfonic acid and aryl sulphonic acid ), inorganic salt ( NH 4 Fe(SO 4 ) 2 ∙12H 2 O , NaHSO 4 ∙H 2 O , Fe 2 (SO 4 ) 3 ∙xH 2 O and FeCl 3 ∙6H 2 O ), heteropolyacid ( H 4 O 40 W 12 and TiSiW 12 O 40 /TiO 2 ) and solid super acid ( Ti (SO 4 ) 2 /TiO 2 and Zr(SO 4 ) 2 ∙4H 2 O ) have been reviewed in the present paper. The yields of iso-amyl benzoate are improved by the addition of above catalysts. These methods are having the advantages of simple process and low investment costs.

The Study on Solid Superacid Synthesis of K12A with Manufacturing Equipment

By orthogonal design method, Catalytic activity of /ZrO2 solid superacid is studied, and the influence of catalyst characteristic and structure by manufacturing equipment is issued. It is concluded that the best prepared conditions of the superacid catalyst /ZrO2 for the synthesis of Octyl-Polyglycoside are followed:(1) PH=9.5; (2) calcined temperature at 500; (3) M(H2SO4)=0.5mol/L. Using this kind of catalyst the conversion of glueoside may reach as high as 96% in the synthesis of OCtyl-Polyglycoside and the selectivity is very high for the synthesis of Octyl-Polyglycoside. By introducing other metal oxide, the catalytic activity of complex solid superacid is studied.

Benzene adsorption and protonation in perfluorosulfonic membrane

Benzene adsorption in a perfluorosulfonic membrane was performed through deep dehydration of the latter over the phosphoric anhydride. The subsequent UV irradiation is accompanied by a gradual transition of the benzene π-complexes in the protonated form C6H7+ that allows us to consider the perfluorosulfonic membrane as a solid superacids. The photoexcitation on the absorption band of adsorbed carbonium ion causes its fluorescence in the region of 450–600 nm.

Synthesis and Characterization of Sulfated TiO2 Nanorods and ZrO2/TiO2 Nanocomposites for the Esterification of Biobased Organic Acid

TiO(2) nanorods and ZrO(2)-modified TiO(2) nanocomposites have been prepared by hydrothermal synthesis and the deposition-precipitation method. Their sulfated products were tested as solid superacid catalysts for the esterification of levulinic acid which was used as a model bio-oil molecule. SEM and TEM characterization showed that TiO(2) nanorods with diameters ranging from 20 to 200 nm and with lengths of up to 5 μm were synthesized by a hydrothermal method at 180 °C. ZrO(2) nanoparticles with the diameters ranging from 10 to 20 nm were evenly deposited on TiO(2) nanorods. IR and XPS results suggested that sulfated ZrO(2)/TiO(2) nanocomposite has higher content of sulfate groups on the surface with a S/(Zr+Ti) ratio of 13.6% than sulfated TiO(2) nanorods with a S/Ti ratio of 4.9%. The HPLC results showed that sulfated ZrO(2)/TiO(2) nanocomposite have enhanced catalytic activity for esterification reaction between levulinic acid and ethanol compared to sulfated TiO(2) nanorods. The conversion of levulinic acid to ethyl levulinate can reach to 90.4% at the reaction temperature of 105 °C after 180 min.

ChemInform Abstract: Rare Earth Solid Superacid Catalyzed Friedel—Crafts Acylation of Ferrocene.

Abstract The Friedel–Crafts acylation of ferrocene catalyzed by a new type of catalyst of rare-earth solid superacid sulfated zirconia SZR3+ was developed. Comparison of catalytic activities between different solid acid catalysts is presented. The catalyst, sulfated zirconia ytterbium SZNYb3+, showed interesting catalytic properties for preparation of acylferrocenes. Furthermore, the catalyst could be regenerated and reused in succession after simple filtration.

Catalytic Effects of Super Acid SO&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;2-&lt;/sup&gt;/γ-Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; to PET Depolymerization under Microwave Irradiation

The effects of different temperatures on catalytic hydrolysis of polyethylene terephthalate(PET) by solid super acids SO42-/γ-Al2O3as a catalyst under microwave irradiation were studied, and in the meantime, the morphology analysis of the undepolymerized PET under the same temperature was investigated by SEM. The results indicate that the depolymerization rate of PET is seriously influenced by reaction time and temperature. The depolymerization mechanism is changed by the solid super acid SO42-/γ-Al2O3, and the depolymerization rate is higher than that of with no catalyst in the whole process of reaction.

Synthesis of Ethyl Acetate Using Packing Solid Super Acid Catalyst of SO&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;2-&lt;/sup&gt;/Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; by Catalytic Distillation

Ethyl acetate was synthesized by catalytic distillation using packing solid super acid catalyst of SO42-/Al2O3made by oneself. The effects of process parameters such as the ratio between acetic acid and ethanol, the feed flow rate of ethanol and reflux ratio on catalytic distillation were observed. The best operation parameters were determined. It was beneficial for synthesis of ethyl acetate when n(acetic acid)/n(ethanol) was 1/3, the feed flow rate of ethanol was 3mol/l and reflux ratio was 2.

Characteristics of Solid Super Acid SO&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;2-/&lt;/sup&gt;TiO&lt;sub&gt;2&lt;/sub&gt;-Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;-SnO&lt;sub&gt;2&lt;/sub&gt; during Conversion of Glucose to Levulinic Acid

The effects of catalyst amount on the yields of levulinic and hydroxymethyl furfural were investigated during conversion of glucose to levulinic acid catalyzed by solid super acid SO42- / TiO2-Al2O3-SnO2. XRD and XPS were used to analyse the characteristics of solid super acid SO42- / TiO2-Al2O3-SnO2 before reaction and after reaction. The results showed that: solid super acid SO42- / TiO2-Al2O3-SnO2exhibited good catalytic activity in the reaction of hydrolysis of glucose to produce levulinic acid. There were three obvious peaks in these XRD spectra. The peaks on 44.6° and 67.1° were the characteristic diffraction peaks of γ-Al2O3. The anatase characteristic diffraction peak was on 37.4°. The catalyst was steady in the process. The binding energy of S 2p was similar to the binding energy of standard S6+ 2p in the S 2p XPS spectrum of solid super acid. O 1s XPS was double-peaked spectrum. The increase of element C was the main reason of inactivation of catalyst.

Hydrolysis of Dimethyl Ether over Heteropoly Acids Catalyst

Heteropoly acide(HPA), as one kind of solid-super acid catalysts, has been researched and applied extensively. Using SBA-15 and ZSM-5 as carriers, HPA catalysts with different types and contents were applied in this work for the hydrolysis of dimethyl ether(DME). It had been found that ZSM-5 was a proper carrier, and its supported phosphotungstic acid exhibited relatively high catalytic activity in this low-temperature hydrolysis reaction.

Synthesis, characterization and catalytic activity studies on cordierite honeycomb coated with ZrO2 based solid super acids

Abstract Cordierite honeycomb coated with solid acids such as ZrO 2 , Mo/ZrO 2 and W/ZrO 2 were synthesized. These solid acid catalysts were also synthesized in their powder forms. The catalytic materials were characterized for their physicochemical properties such as surface area, surface acidity, crystallinity and morphology by using techniques such as BET, NH 3 -TPD/ n -butylamine back titration, powder XRD and SEM respectively. The catalytic activity of these catalytic materials was determined in an acid catalyzed transesterification reaction of methyl salicylate with phenol to synthesize phenyl salicylate (salol). The effect of concentration of Mo or W ions on ZrO 2 , nature of the catalyst (whether honeycomb coated or powder form), reaction temperature, reaction time and reusability of the catalytic material in transesterification was studied. Formation of diphenyl ether as a by-product was observed on increasing the concentration of Mo or W ions on ZrO 2 and also at higher reaction temperature. The catalytic activity of catalytic materials was correlated with surface acidity and the crystalline phases of catalytic material. Transesterification reactions were also carried out with methyl salicylate and benzyl alcohol or cyclohexanol to synthesize their respective salicylate esters. A probable mechanism of transesterification of methyl salicylate with an alcohol is also proposed. The honeycomb catalysts were found to be efficient, ecofriendly, economical and reusable catalysts compared to their powder forms.

Novelties of combustion synthesized and functionalized solid superacid catalysts in selective isomerization of styrene oxide to 2-phenyl acetaldehyde

Combustion synthesis leads to very interesting characteristics to inorganic oxides which could be further modified to render them catalytic properties. Several new approaches were studied to make a novel superacidic sulfated zirconia called fuel lean sulfated zirconia (FLSZ), by combustion synthesis. FLSZ was fully characterized and used in a reaction of industrial relevance. The isomerization of styrene oxide to 2-phenyl acetaldehyde was studied by using several solid acid catalysts. 2-Phenyl acetaldehyde finds applications in the synthesis of fine chemicals, intermediates, speciality chemicals, flavors and fragrances. Among various catalysts studied FLSZ was found to give the best activity and selectivity to 2-phenyl acetaldehyde at 100°C using cyclohexane as a solvent. Process parameters were optimized by conducting a systematic investigation. The kinetics of the reaction was also studied. The catalyst is robust, recyclable and found to be highly active and selective. The overall process is 100% atom economical, green and clean.

Green synthesis of cyclohexanone glycerol ketal catalyzed by a solid superacid

Abstract This paper discusses the synthesis of a glycerol ketal compound obtained from condensation reaction of cyclohexanone with glycerol catalyzed by a solid superacid. The solid superacid SO42-/TiO2-La2O3 was prepared using coprecipitation and impregnation method and characterized by X-ray diffraction, thermogravimetric analysis, Fourier transform infrared spectroscopy and elemental analysis. The surface acidity was measured by thermogravimetric analysis of adsorbed n-butylamine. In order to achieve the optimal reaction conditions, five impact factors: molar ratio of glycerol to cyclohexanone, catalyst calcination temperature, reaction time, catalyst amount and molar ratio of Ti/La were investigated in the experiments. Synthesized ketal compounds were analyzed by GC-MS/MS. Under the best conditions, the cyclohexanone glycerol ketal yield could reach up to 97%.

Atom efficient Friedel–Crafts acylation of toluene with propionic anhydride over solid mesoporous superacid UDCaT-5

Friedel–Crafts acylation is ubiquitous in industry and is typically carried out by using more than stoichiometric quantities of homogeneous catalysts. This creates pollution. In this work, acylation of toluene was studied in liquid phase with propionic anhydride with a variety of solid superacids to produce 4′-methylpropiophenone (4′-MPP). The solid superacids were modified versions of zirconia, namely, UDCaT-4, UDCaT-5 and UDCaT-6 developed in our laboratory; amongst which UDCaT-5 was the most active, selective and robust catalyst. The effects of various reaction parameters on the rate of reaction and selectivity were investigated to deduce the intrinsic kinetics of the reaction. The reaction is free from any external mass transfer as well as intraparticle diffusion limitations and is intrinsically kinetically controlled. The acylation conditions were: temperature 180°C, toluene to propionic anhydride molar ratio 5:1, catalyst loading 0.06gcm−3, speed of agitation 1000rpm, under autogenous pressure in a stainless steel autoclave reactor. Propionic acid generated in situ also reacts sequentially with toluene to give 4′-MPP. A conversion of 62% of priopionic anyhydride is obtained after 3h, with 100% mono-acylated product containing 67% 4′-MPP. Water is the only co-product of the overall reaction. A suitable kinetic model was developed. The reactions were carried out without using any solvent in order to make the process cleaner and greener.

Preparation and properties of fluorine-containing polysiloxanes obtained via ring-opening copolymerization of trifluoropropyltrimethylcyclotrisiloxane with cyclotetrasiloxane catalyzed by rare earth solid superacid SO$_{4}^{2-}$/TiO2 /Ln3+

Traditional catalysts such as (CH3)4NOH, NaOH, KOH, n-BuLi and CF3SO3H can catalyze the copolymerization of trifluoropropyltrimethylcyclotrisiloxane with cyclotetrasiloxane to afford fluorine-containing polysiloxanes. However, use of these catalysts poses significant difficulties in handling and separation. In this work, fluorine-containing polysiloxanes were synthesized through a novel and environmentally friendly method: ring-opening copolymerization of trifluoropropyltrimethylcyclotrisiloxane with cyclotetrasiloxane catalyzed by rare earth solid superacid SO/TiO2/Ln3+. The effects of reaction conditions were examined in detail. The yield sequence of various rare earth catalysts is Nd ∼ La ∼ Y ∼ Sm > Gd, while the number-average molecular weight sequence is Nd > La > Y > Sm > Gd. The optimum conditions for the ring-opening copolymerization of trifluoropropyltrimethylcyclotrisiloxane with cyclotetrasiloxane are as follows: [Nd3+] = 0.05 mol L−1 and mol L−1 in the immersing solution, SO/TiO2/Nd3+ calcined at 500 °C and the copolymerization conducted at 80 °C for 40 min. Structures of resulting copolymers were characterized using size exclusion chromatography, 1H NMR spectroscopy, differential scanning calorimetry, thermogravimetric analysis and contact angle measurements. According to the copolymerization features, a cationic equilibrium reaction mechanism is proposed. Copyright © 2012 Society of Chemical Industry