Papers by Keyword: Solid Acid

Abstract: The synthesis of acid-activated Al₂O₃-pillared bentonite as a solid acid catalyst has been completed. The pillarization process was carried out using the varying pf calcination time, mole OH/Al ratio, and mmol of Keggin/bentonite to determine the optimum total acidity. The higher the calcination time, (OH/Al) ratio, and suspension concentration, the greater the acidity of ​​the Al₂O₃-pillared bentonite. The optimum conditions were achieved at a calcination time of 20 minutes, a mol of (OH/Al) ratio of 2.2, and Keggin/bentonite of 10 mmol with a total acidity of 11.76 mmol gram ammonia and 2.44 mmol/gram pyridine. The pillared bentonite had a surface area of ​​154.64 m²/g and a pore diameter of 3.38 nm. The pillaring process was successfully increasing the basal spacing of natural bentonite from 14.77 to 17.78.

Abstract: SO₄^2-/ Al-Fe-activated solid acid catalysts had been prepared in different conditions using cross-linking method, and characterized by XRD, BET, FTIR spectra and TG-DTA. The catalyst performed highly catalytic activity in the hydration of turpentine to α-terpineol.

Abstract: SO₄²⁻/SnO₂-ZrO₂ catalyst, organic acids, inorganic acids and sulfates have been applied for the alcoholysis of sugars to butyl levulinate using n-buthanol as solvent and reactant. The combined effect of solid acid and H₂SO₄ showed a high catalytic activity for the selective conversion of cellulose to butyl levulinate at 200 °C, whereas the glucose yielded around 40 mol% butyl levulinate. The oxalic acid and CuSO₄ also showed great activity towards the cellulose alcoholysis.

Abstract: The solid acid catalyst (ACSA) for the gutter oil esterification to biodiesel was prepared via active carbon as raw material by introducing the-SO₃H group onto the surface of it. The ACSA were characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and elemental analysis (EA), respectively. And the results showed that the-SO₃H groups were successfully introduced onto the surface of the active carbon and the containing of the-SO₃H groups are higher than 0.017g per gram of ACSA.

Abstract: SO₄^2-/ Al-Fe-activated solid acid catalyst has been prepared using cross-linking method, and characterized by FTIR spectra, TG-DTA, XRD analysis. The catalyst is able to effectively catalyse the hydration of turpentine to α-terpineol, with the conversion up to 40% after > 4 uses.

Abstract: Catalytic hydrolysis decomposition of dichlorodifluoromethane (CCl₂F₂) in the presence of water vapor and oxygen was studied over a series of solid acids using a fixed-bed reactor. Solid acid MoO₃/ZrO₂ displayed the highest activity, over which the conversion of CCl₂F₂ reached 100 % at 250 °C. CO₂ was the main-product and the selectivity to CClF₃ remained lower than 28.0 %. CO was not detected as by-product. The decomposition activity depended on the calcination temperature and the ZrO₂ content. The activity of solid acid MoO₃/ZrO₂ correlates well with its specific surface area and the amount of medium-strong acid sites on the surface. To explain the reaction mechanism for CCl₂F₂ catalytic decomposition over MoO₃/ZrO₂, a surface intermediate, O_surface-CF2-O_surface is proposed.

Abstract: The p-toluene sulphonic acid (PTSA)/MCM-41 was prepared by impregnation method with self-synthesized MCM-41. The investigation of effects on PTSA solution concentration was investigated and the catalyst prepared with 0.1mol/L PTSA performed best. Oleic acid was chosen as a simulation of high-acid-value oil to esterify with methanol. The experimental results showed that PTSA/MCM-41 was a high active catalyst in esterification. The optimal condition was as following: the reaction temperature was 80°C, the methanol/oleic acid molar ratio was 5:1, the catalyst amount was 5% (wt. /wt.) of the oleic acid, and reaction time was 1h. Under this condition, the oleic acid conversion could reach 94.3%. The stability of the catalyst was very well for the oleic acid conversion can still maintain 92.8% after used four times.

Abstract: The initial activity, selectivity, and especially catalytic stability of mesoporous MCM-41 supported phosphotungstic acid (HPW) prepared by ultrasonic-assisted impregnation (UAI) method and the HY zeolite were contrastively investigated for alkenylation of p-xylene with phenylacetylene in a fixed-bed continuous flow reactor. N2 adsorption-desorption, FT-IR, X-ray diffraction (XRD) and NH3 temperature-programmed (NH3-TPD) desorption characterization techniques were employed to explore the relationship of catalyst nature and catalytic performance in alkenylation. Results illustrate that the as-prepared HPW/MCM-41 catalyst exhibits notably superior catalytic activity, selectivity and stability to microporous HY zeolite, ascribed to its well-ordered mesoporous architecture, appropriate acidic sites and high dispersity of HPW phase.

Abstract: Biomass represents an abundant and relatively low cost carbon resource that can be utilized to produce platform chemicals such as levulinic acid. This study focused on the effect of SO₄^2-/TiO2-Al₂O₃-SnO₂ solid acid catalyst on the catalytic performance in levulinic acid production from biomass-derived carbohydrates glucose. The SO₄^2-/TiO₂-Al₂O₃-SnO₂ solid acid catalyst showed a high catalytic activity for the selective conversion of glucose to levulinic acid. Experimental results showed that SO₄^2-/TiO₂-Al₂O₃-SnO₂ solid acid had markedly catalytic effects on the conversion of glucose to levulinic acid. With SO₄^2-/TiO₂-Al₂O₃-SnO₂ solid acid as the catalyst, an optimized ethyl levulinic acid was obtained at 180 °C for 2 h with glucose dosage of 2 wt% and 3 g SO₄^2-/TiO₂-Al₂O₃-SnO₂ solid acid catalys and the levulinic acid yield was 74.05%.

Abstract: The synthesis of biodiesel expressed as fatty acid methyl ester (FAME) were studied to achieve an economic and practical method for utilization of used cooking oil (UCO). UCO samples with the acid value of more than 80 mgKOH/g mixed with methanol were heterogeneously catalyzed by solid aminosulfonic acid under some conditions . The conversion of UCO into FAME was 86.0% at the reaction time of 2 hours, mole ratio of methanol to UCO of 5:1, showing much higher catalyzed activity of solid aminosulfonic acid. the samples of FAME prepared from UCO was analyzed by GC/MS and the results showes that the majority of biodiesel has fatty acid methyl esters of carbon lengths from C₁₄–C₂₄, with an average of C₁₈ methyl ester.