Synthesis and Evaluation of Levulinic Ester as Biodiesel Additives

In this study, the SO42-/TiO2-La2O3-Fe2O3 catalyst was prepared and tested in the conversion of fructose to ethyl levulinate . The catalyst was characterized from the point of view of the textural analysis, FT-IR analysis, acid strength distribution, X-ray powder diffraction and pyridine adsorption IR spectra. The influence of the reaction parameters on the ethyl levulinate yield was study. The maximum yield of 37.95% in levulinate esters was obtained at 180 �C, 2 g catalyst and 4 h reaction time. The effect of ethyl levulinate addition to diesel-biodiesel blend in different rates, i.e, 0.5, 1, 2.5, 5 (w.t %) on density, kinematic viscosity and flash point was evaluated and compared with the European specification.

Renewable Butene Production through Dehydration Reactions over Nano-HZSM-5/γ-Al2O3 Hybrid Catalysts

The development of new, improved zeolitic materials is of prime importance to progress heterogeneous catalysis and adsorption technologies. The zeolite HZSM-5 and metal oxide γ-Al2O3 are key materials for processing bio-alcohols, but both have some limitations, i.e., HZSM-5 has a high activity but low catalytic stability, and vice versa for γ-Al2O3. To combine their advantages and suppress their disadvantages, this study reports the synthesis, characterization, and catalytic results of a hybrid nano-HZSM-5/γ-Al2O3 catalyst for the dehydration of n-butanol to butenes. The hybrid catalyst is prepared by the in-situ hydrothermal synthesis of nano-HZSM-5 onto γ-Al2O3. This catalyst combines mesoporosity, related to the γ-Al2O3 support, and microporosity due to the nano-HZSM-5 crystals dispersed on the γ-Al2O3. HZSM-5 and γ-Al2O3 being in one hybrid catalyst leads to a different acid strength distribution and outperforms both single materials as it shows increased activity (compared to γ-Al2O3) and a high selectivity to olefins, even at low conversion and a higher stability (compared to HZSM-5). The hybrid catalyst also outperforms a physical mixture of nano-HZSM-5 and γ-Al2O3, indicating a truly synergistic effect in the hybrid catalyst.

Study on n-heptane Conversion Over Ni-HZSM-5 Zeolite Catalysts

The conversion of n-heptanes by the chromatographic pulse method in the temperature range of 673 - 823K on the MFI zeolites modified by ion exchange with Ni(NO3)2 aqueous solutions was studied. The catalysts, HZSM-5 (SiO2/Al2O3 = 33.9), and Ni-HZSM-5 (wt. % Ni, 0.57, 1.09, 1.34,) having different acid strength distribution exhibit a conversion and a yield of aromatics depending on temperature and metal content. The highest selectivity for n-heptanes aromatization was obtained on the catalyst Ni3-HZSM-5 (wt. % Ni 1.34) at 823K. The metal actions and the acidic properties of zeolites have an important effect on the aromatization of n-heptanes.

Performance of Ag-HZSM-5 Zeolite Catalysts in n-heptane Conversion

The conversion of n-heptanes into aromatic hydrocarbons benzene, toluene and xylenes (BTX), by the chromatographic pulse method in the temperature range of 673 - 823K was performed over the HZSM-5 and Ag-HZSM-5 zeolites modified by ion exchange with AgNO3 aqueous solutions. The catalysts, HZSM-5 (SiO2/Al2O3 = 33.9), and Ag-HZSM-5 (Ag1-HZSM-5 wt. % Ag1.02, Ag2-HZSM-5 wt. % Ag 1.62; and Ag3-HZSM-5 wt. % Ag 2.05 having different acid strength distribution exhibit a conversion and a yield of aromatics depending on temperature and metal content. The yield of aromatic hydrocarbons BTX appreciably increased by incorporating silver cations Ag+ into HZSM-5.

Effect of sequential desilication and dealumination on catalytic performance of ZSM-5 catalyst for pyridine and 3-picoline synthesis

A sequential procedure of alkaline treatment followed by SiCl4 or hydrothermal treatment has been investigated to obtain a tailored ZSM-5 catalyst for the synthesis of pyridine bases. The major function of alkaline treatment is desilication; however, it is accompanied by the extraction of framework aluminum, which formed the extra-framework alumina and amorphous alumina by realumination. Moreover, a large number of intracrystalline meso- and macropores and silanol groups are created. The desilication and realumination cause the ratio of Lewis acid sites to Brönsted acid sites (L/B) to increase. The subsequent SiCl4 or hydrothermal dealumination increases both L/B ratio and acid strength. The introduced hierarchical pores and changed acid strength distribution by the alkaline treatment improve the stability of the catalysts; the generated stronger acid sites by dealumination benefits the yields of pyridine bases; and the increased L/B by the sequential treatment promotes the selectivity of pyridine over 3-picoline.