Sulfated Zirconia Catalysts Research Articles

Catalytic Thermal Cracking of Postconsumer Waste Plastics to Fuels. 1. Kinetics and Optimization

Thermogravimetric analysis (TGA) was used to investigate thermal and catalytic pyrolysis of waste plastics such as prescription bottles (polypropylene/PP), high density polyethylene, landfill liners (polyethylene/PE), packing materials (polystyrene/PS), and foams (polyurethane/PU) into crude plastic oils. In the first phase of this investigation, a statistical design experiments approach identified reaction temperature and time as the most important factors influencing product oil yield. Kinetic parameters including activation energy determined for both catalytic and noncatalytic processes showed a reduction in activation energy for the catalytic reactions. In the second phase, the interactions of reaction temperature and time with a number of catalysts were investigated to determine the effect on the yield of crude plastic oil. It was found that Y-zeolites increased conversion at reduced temperature for PP and PE while spent fluid catalytic cracking and sulfated zirconia catalysts supported pyrolytic dec...

Preparation, Characterization and Catalytic Activity of Sulfated Zirconia by Varied Sol-Gel Method

The sulfated zirconia catalysts were was prepared by sol–gel processes consist of varied templating method. Both preparations consist of sol-gel synthesis of zirconium dioxide followed by sulfatation process by using NH4SO4 solid reaction method. Two different templating agent; urea and cetyltrimetyl ammonium bromide was used in sol-gel processes. The prepared material was characterized using scanning electron microscope (SEM), x-ray diffraction (XRD) and Brunauer–Emmett–Teller (BET) measurements. From the XRD measurement it can be concluded that both materials consist of ZrO2 in combined phases while from BET surface area analysis it can be noted that material prepared by urea template has higher specific surface area compared to that use CTAB template. Both materials exhibit the activity as acid catalyst in microwave assisted conversion of citronellal. It is also confirmed that the higher the surface area the higher total conversion of citronellal obtained. Study on the correlation between physicochemical properties of materials with the catalytic activity was discussed in this paper.

Glycerol etherification with benzyl alcohol over sulfated zirconia catalysts

Glycerol (GLY) etherification with benzyl alcohol (BA) was conducted with different zirconia-based heterogeneous acid catalysts, aiming to produce mono- (ME) and dibenzyl glycerol ethers (DE). Physicochemical properties of the prepared catalysts were obtained through XRD, SEM and adsorption of ammonia. The catalytic tests were performed at different temperatures (120–140°C) and initial reactant mass ratios (GLY:BA 1:1 and 2:1). The highest BA conversions were obtained with the catalyst having the highest sulfuric acid content (2S/ZrO2). An increase in the reaction temperature and the GLY:BA initial mass ratio led to an increase in the BA conversion. Two kinetic models (a potential and a hyperbolic approach) were proposed to describe the process performance, including not only reactants evolution with time, but also that of ME, DE and the undesired self-condensation product of BA (benzyl ether, BE). Kinetic parameters for each model were estimated by data fitting and both models were able to accurately describe the evolution of the system, in terms of reactants and product distribution as a function of time under the experimental conditions studied.

Sulfated zirconia as a novel and recyclable catalyst for removal of olefins from aromatics

A novel sulfated zirconia (ZrO2/SO42−) catalyst was prepared and the catalytic property of this catalyst was compared with active clay and zeolite (USY) in removing olefins from aromatics. Pyridine-FTIR indicated that the abundance of Lewis acid centers on sulfated zirconia is a vital factor for its excellent catalytic activity. N2 adsorption analysis shows that sulfated zirconia is a promising mesopore catalyst material. The superior catalytic performance as well as efficient reusability demonstrated that sulfated zirconia possesses bright application prospects in industry.

Synthesis and characterization of MCM-41-supported nano zirconia catalysts

Series of MCM-41 supported sulfated Zirconia (SZ) catalysts with different loadings (2.5–7.5% wt.) were prepared using direct impregnation method. The acquired solid catalysts were characterized structurally and chemically using X-RD, HRTEM, BET, FT-IR, Raman spectroscopy and TPD analysis. The acidity of the solid catalysts was investigated through cumene cracking and isopropanol dehydration at different temperatures. As the SZ loading increases, the surface acidity of the mesoporous catalysts was enhanced, this was reflected by the higher catalytic activity toward cumene cracking and isopropanol dehydration.

A survey of catalysts for aromatics from fast pyrolysis of biomass

A comparative evaluation of ten catalysts for biomass pyrolysis was performed using poplar (DN-34) as the feedstock. Five of the catalysts consisted of HZSM-5 with different silica:alumina ratios (SAR, 23, 30, 55, 80 and 280). The other five catalysts were sulfated zirconia (SO42− ZrO2), 20% SO42− ZrO2 dispersed on a mesoporous MCM-41 silica support, Al–MSU–S alumnosilicate exhibiting a foam-like mesopore structure, Al–MSU–S aluminosilicate exhibiting wormhole mesopores, and a bauxite waste product known as red mud. Analytical pyrolysis in tandem with GC/MS showed that all of the catalysts except for HZSM-5 resulted in low aromatic chemical production. Highly acidic sulfated zirconia catalysts were not selective to aromatics and produced significant coke and non-condensable gases. Mesoporous MSU–S catalysts exhibiting high pore volume and acidity also gave high gas and coke yields. Among the HZSM-5 catalysts evaluated, those with the lowest SAR provided the highest yields of total aromatics and the lowest levels of undesired coke.

Esterification of palmitic acid with methanol over template-assisted mesoporous sulfated zirconia solid acid catalyst

The esterification of palmitic acid with methanol was studied over mesoporous sulfated zirconia (SZ) solid acid catalyst, prepared by using CTAB cationic surfactant as a template. The effect of various reaction parameters has been studied. The catalyst showed an excellent activity with 88–90% yield of methyl palmitate at 60°C after 5–7h. The reaction follows pseudo-first order kinetics under the reaction conditions studied with a reaction rate of 48.67mmolh−1g−1 and turnover frequency of 6.96h−1. It is noteworthy that SZ catalyst showed comparable activity to conventional Brönsted acids namely H2SO4 and p-TSA; as well as it exhibited higher activity than various other heterogeneous catalysts such as zeolites, ion-exchange resins and acid clay.

Sulfated Zirconia Catalyst for Hydrolysis of Palm Oil Lignocellulosic Wastes

Abstract The waste plant materials remaining from palm oil extraction consist of cellulose, hemicellulose and lignin. They are potential sources of cellulose, which can be used as raw material for production of fermentable sugar. In this study, a single stage of heterogeneous acid catalyst hydrolysis were carried out in ionic liquid solution over sulfated zirconia catalysts prepared by modified sol gel method. Among the sulfated zirconia catalysts tested, sulfated zirconia prepared by SFE showed the highest hydrolysis catalytic activity up to 37.20% in EFB treated and 53.95% in frond treated. In addition, the process variable of reaction time hydrolysis was also investigated over both sulfated zirconia catalyst. The objective of this research is to do catalytic hydrolysis of lignocellulosic waste by using sulfated zirconia catalyst prepared by sol gel method.

Direct synthesis of dimethyl ether from CO2 hydrogenation over Cu–ZnO–ZrO2/SO42−–ZrO2 hybrid catalysts: effects of sulfur-to-zirconia ratios

Methanol can be dehydrated to form DME over sulfated zirconia catalysts via pathway I, if the sulfur content is low, and pathway II, if the sulfur content is high.

Surface properties and memory effect: Key factors in determining the catalytic efficiency of sulfated zirconia

Three series of zirconia catalysts based on various precursors and grafted with sulfates were synthesized, then calcined at two different temperatures (500 and 600°C) and tested in the n-hexane isomerization. The catalysts based on commercially sulfated zirconium(IV)-hydroxide, and alkoxide prepared at two altered pH values were characterized by means of BET, XRD, SEM, and FTIR methods and relevant procedures. The final catalytic efficiencies were correlated with their physico-chemical properties (surface, textural, structural and morphological ones). It was recognized that the sulfated zirconia catalyst based on commercially sulfated zirconium(IV)-hydroxide and calcined at the lower temperature demonstrated the highest initial activity among all the tested catalysts due to the favorable total acidity, the density of sulfates, the type of acidic active sites, the mesoporous system and nanostructure. Slightly lower but comparable activity of the sulfated zirconia catalyst based on alkoxide and prepared at lower pH is the result of the different memory effect of the starting material and its original properties, and also something different physicochemical features.

Superficial effects and catalytic activity of ZrO2–SO42− as a function of the crystal structure

As assessment was made of the influence of the crystal structure on the activity of SO42−–ZrO2 catalysts for the acid-catalyzed reactions of sucrose inversion and the esterification of fatty acids with glycerol. Purely monoclinic or purely tetragonal SO42−–ZrO2 catalysts were synthesized by sulfation with 1M sulfuric acid of different ZrO2 starting materials of defined crystal phase. The final catalysts were obtained by calcination at 400°C, a relatively mild temperature for this kind of materials. Structural and morphological characterization tests showed that the crystal phase of zirconia had an influence on the properties of the sulfated zirconia catalysts. Monoclinic and tetragonal catalysts had different acidities and also different levels of activity in the reactions. Better results in the sucrose inversion tests were obtained using tetragonal phase catalysts while monoclinic phase materials were better catalysts for glycerol esterification.The catalysts were further characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and nitrogen physisorption. The acidity was measured by amine titration using Hammett indicators and FT-IR absorption of adsorbed pyridine.

Ferric-manganese doped sulphated zirconia nanoparticles catalyst for single-step biodiesel production from waste cooking oil: Characterization and optimization

ABSTRACTBiodiesel of waste cooking oil origin is gaining attention as a replacement for current fossil fuels, as its low-priced, recycled feedstock shall prevent food source competition, which is estimated to happen with current biodiesel production processes. As a result, waste cooking oil has been claimed to be a highly potential feedstock for biodiesel production. In the present research work, Fe-Mn doped sulphated zirconia catalyst was synthesized and used in simultaneous esterification and transesterification of waste cooking oil to biodiesel synthesis. The catalyst was prepared through the impregnation method and characterized by using XRD, TPD-NH3, FT-IR, BET, and TEM. Response surface methodology (RSM) in conjunction with the central composite design (CCD) was applied to statistically evaluate and optimize the biodiesel preparation process. It was found that the synthesis of biodiesel achieved an optimum level of 97.2% waste cooking oil methyl ester’s (WCOME’s) yield at the following reaction conditions: methanol/oil molar ratio: 10:1, catalyst concentration: 3.0 wt %, and reaction temperature: 160 °C. The extremely high WCOME’s yield of 97.2% was proved to be due to high acidity, surface area, and large pore diameter; reactants can easily diffuse into the interior pore of the catalyst and allow them to be in contact with active sites that enhance catalytic activity.

Pt, Re and Pt–Re incorporation in sulfated zirconia as catalysts for n-pentane isomerization

Two groups of modified Sulfated Zirconia (SZ) catalysts were prepared by the sol–gel method. The first group was modified by four different concentrations of Pt metal (0.15, 0.30, 0.45 and 0.60wt%), whereas the second group contained Pt–Re combinations on SZ. All the prepared catalysts were characterized by XRD, TPR, TEM, TGA, IR spectroscopy as well as surface properties using the BET method. The catalytic activity of the catalysts was examined for the hydroisomerization of n-pentane to iso-pentane. The catalytic activity was found to increase with increasing Pt concentration in the monometallic catalysts. The combination of Re ion with Pt on SZ results in significant changes in the characters and activities of the catalysts. The 0.45wt%Pt+0.15wt%Re/SZ catalyst exhibited the highest selective compared to other metal ratios investigated.

Solvent-free aminolysis of aliphatic and aryloxy epoxides with sulfated zirconia as solid acid catalyst

Single-step and two-steps synthetic procedure for the synthesis of sulfated zirconia (SZ) was developed, which were calcined at 500, 600 and 700°C and characterized by various physico-chemical methods such as PXRD, FTIR, surface area, microanalysis, NH3-TPD and DRIFT analysis. These SZ materials were then employed as solid acid catalysts for the aminolysis of different aliphatic/aromatic terminal, aryloxy and meso epoxides with aromatic and aliphatic amines under ambient conditions. Amongst the catalyst prepared, SZ-2-600 prepared in two-steps and 600°C calcined was found to be the most efficient catalyst to give β-amino alcohols in up to 98% yield and >99% regioselectivity. The SZ catalyst was successfully recycled and reused up to six catalytic runs with intact efficiency.

The catalytic performance of sulfated zirconia in the dehydration of methanol to dimethyl ether

Sulfated zirconia catalysts were prepared by wetness impregnation of zirconium hydroxide with an aqueous solution of (NH4)2SO4 with SO42− loadings (1–30%, w/w) and calcined at 450°C for 3h in a static air atmosphere. The catalysts were characterized by FT-IR, XRD, TEM and BET measurements. The surface acidity of the catalysts was investigated by the dehydration of isopropanol and the adsorption of pyridine (PY) and 2,6-dimethyl pyridine (DMPY). The catalysts were tested for dehydration of methanol in a fixed-bed reactor at 230°C using air as a carrier gas. The results revealed that among different catalysts, 10% SO42− supported onto zirconia showed the highest catalytic activity with 83% conversion and 100% selectivity toward dimethyl ether. A good correlation was found between the acidity of the catalysts and their ability to dehydrate methanol.

Comparative study of aerogels nanostructured catalysts: Ni/ZrO2–SO4 2− and Ni/ZrO2–Al2O3–SO4 2−

A series of Ni/ZrO2–SO4 2− and Ni/ZrO2–Al2O3–SO4 2− catalysts were prepared in one step by the sol–gel method and dried in hypercritical conditions of the solvent. The characteristic properties of those solids were investigated using many techniques: the XRD, the physisorption of N2, the IR, the UV–visible, and the X-ray photoelectron spectroscopy (XPS). Textural analysis reveals the mesoporosity of all the aerogel catalysts. Moreover, the addition of alumina to nickel sulfated zirconia at high calcination temperature increased twice the specific surface area, from 72 to 158 m2/g. XRD patterns show that nickel-promoted sulfated zirconia calcined at different temperature develops the tetragonal and the monoclinic ZrO2 phase, whereas the nickel sulfated zirconia alumina exhibits only the ZrO2 tetragonal phase. The addition of aluminum to nickel sulfated zirconia induces significant changes in symmetry of nickel by the migration of Ni ions from octahedral to tetrahedral coordination. XPS spectroscopy shows that the nickel in Ni/ZrO2–SO4 2− catalysts is more reducible than those in Ni/ZrO2–Al2O3–SO4 2−. Nickel sulfated zirconia catalyst exhibits higher activity than nickel sulfated zirconia alumina, in the n-hexane isomerization reaction.

Synthesis and Performance of Sulfated Zirconia Catalyst in Esterification of Oleic Acid

In this work, the performance of sulfated zirconia catalyst used in the synthesis of biodiesel by esterification of oleic acid was studied. For catalyst preparation the zirconium dioxide (ZrO) by Aldrich was used as precursor. The sulfated zirconia obtained was calcined for 3 hours at different temperatures (200, 400, 600 and 700 °C) in an oxygen atmosphere. Each of the calcination conditions generated a sample of catalyst, which was used in the esterification reaction. The esterification reaction was carried out using reagents such as oleic acid and methanol at a molar ratio 1:20. The sulfated zirconia catalyst was used in the reaction in various proportions by weightrelative to the weight of oleic acid (0.5, 1.0, 3.0 and 5%). The analysis of methyl ester conversion was performed by gas chromatography and mass spectrometry (CGMS) and the percentage area of the characteristic peaks as methyl oleate was quantified. A characterization of sulfated zirconia was also performed using scanning electron microscopy (SEM) and X-ray diffraction (XRD). Finally, the catalyst performance was studied in the reduction of the acid index (AI) and the conversion of free fatty acids of oleic acid and compared to other commonly used catalyst for this purpose, which is concentrated sulfuric acid (H2SO4).

The effect of sulfate contents on the surface properties of iron–manganese doped sulfated zirconia catalysts

The iron–manganese doped sulfated zirconia catalysts were prepared via precipitation method; the sulfation was carried out by impregnation with different amounts of sulfate (4%, 10% and 16% SO4−2 by weight) with the addition of Fe–Mn doped and calcined at 600°C for 3h. The prepared catalysts were characterized by TGA-DTA, XRD, BET, FT-IR, TEM, TPD-NH3 and XPS. XRD and BET results revealed that the addition of sulfate imparts special stabilization to the catalytically active tetragonal phase of zirconia. All the iron–manganese doped sulfated zirconia catalysts were found to have strong acid sites, high surface area and small crystallite size.

Bifunctional SO4/ZrO2catalysts for 5-hydroxymethylfufural (5-HMF) production from glucose

The telescopic conversion of glucose to fructose and then 5-hydroxymethylfurfural (5-HMF), the latter a potential, bio-derived platform chemical feedstock, has been explored over a family of bifunctional sulfated zirconia catalysts possessing tuneable acid–base properties. Characterisation by acid–base titration, XPS, XRD and Raman reveal that submonolayer SO4 coverages offer the ideal balance of basic and Lewis–Bronsted acid sites required to respectively isomerise glucose to fructose, and subsequently dehydrate fructose to 5-HMF. A constant acid site normalised turnover frequency is observed for fructose dehydration to 5-HMF, confirming a common Bronsted acid site is responsible for this transformation.

HIDROLISIS LIGNOSELULOSA PELEPAH DAN TANDAN KOSONG KELAPA SAWIT DENGAN KATALIS ZIRKONIA TERSULFATASI

Lignocellulosic biomass which are frond and empty fruit bunches (EFB) is second generation raw material for ethanol production. Lignocellulose usage is expected to create a green process. Utilization of lignocellulose materials into ethanol involved four main processes, i.e pretreatment, hydrolysis/sacharification, fermentation, distillation and dehydration ethanol that was product. This research aims to optimize hydrolysis process of EFB and frond by using sulfated zirconia catalyst characterized its physical and chemical properties as a solid acid catalyst. Catalytic hydrolysis process conducted at 160 DCfor 3 hours gave the highest TRS (Total Reducing Sugar) which is 17,51 % for EFB while for frondfor 2 hours which is 19,23 % .Keyword: Hydrolysis, solid acid catalyst, lignocellulose, frond, EFB, sulfated zirconia