Identification of by-products issued from the catalytic oxidation of toluene by chemical and biological methods

Abstract

Identification of by-products issued from the catalytic oxidation of toluene by chemical and biological methodsIdentification de sous-produits de l'oxydation catalytique du tolue`ne par des me´thodes chimiques et biologiques

The CoAlCeO Mixed Oxide: An Alternative to Palladium-Based Catalysts for Total Oxidation of Industrial VOCs

“…As a first set of experiments, the materials of interest were used to investigate the total oxidation of toluene, and the light-off curves obtained are shown in Figure 2 for all materials. The light-off curves of Pd-based catalysts have been presented in a previous study (Pd/α-Al 2 O 3 , Pd/HY, Pd/CeO 2 and Pd/γ-Al 2 O 3 ) [3]. T 50 and T 100 are defined as the temperature when 50% and 100% conversion, respectively, was observed.…”

“…By contrast, the emission profile of the CoAlCeO mixed oxide revealed a maximum value of less than 1 ppm, namely an order of magnitude lower as compared to the other catalysts. In order to compare the benzene emissions of each material, the methodology presented in a previous study has been used [3], where the emission profiles are characterized by seven parameters. However, only the most relevant parameters are presented in this paper: Q max : maximum quantity emitted observed of the considered byproduct (ppm); T f : temperature at which the byproduct is totally oxidized ( • C); P: persistence of byproduct, corresponding to the difference between T f and T 100 ( • C).…”

“…Therefore, the classification of the catalysts by their performance must be reassessed. Subsequently, according to the T 50 and T 100 , the ranking is as follows, from the most efficient to the least 3 and Pd/HY catalysts is then reduced from 42 • C to 5 • C by considering the T f value corresponding to the temperature at which toluene is totally converted. Thus, the performances of these two materials are very close.…”

“…Is has to be noted that in the case of xylene and isopropanol, the number of their respective byproducts is restricted [31,33], leading to a facilitated identification of these intermediates during the oxidation of xylene/isopropanol mixtures. In this work, both VOCs have a greater number of byproducts with almost similar structures and chemical properties [3,8,9,33]: the identification of a potential byproduct from the addition of toluene and MEK is then more difficult. Additional analyses were performed with a Omnistar Quadrupole Mass Spectrometer (QMS-200) (Pfeiffer Vacuum, Asslar, Germany), configured in "Bargraph" mode to scan all m/z fragments between 1 and 199.…”

Dynamic Processes on Gold-Based Catalysts Followed by Environmental Microscopies

“…. ) or zeolites [1][2][3][4][5][6][7][8]; and the metal-oxide catalysts [9][10][11][12][13][14][15][16][17][18]. Regarding the first class of catalytic materials, the deposition method of the active species, principally in case of noble metals, allows highly dispersed nanoparticles (NPs) to be obtained [19,20] resulting in an important number of active sites available for catalytic reactions.…”