Dissertation > Mathematical sciences and chemical > Chemistry > Physical Chemistry ( theoretical chemistry ),chemical physics > Chemical kinetics,catalysis > Catalytic

Ce-Ag-Mo-PO Catalysts on Selective Oxidation of Propane to Acrolein Reaction

Author ZhangZuo
Tutor WanHuiLin
School Xiamen University
Course Physical and chemical
Keywords Propane Selective oxidation Acrolein Ce-Ag-Mo-P-O Catalyst Redox PH Catalyst dynamic structure Catalytic Reaction Mechanism
CLC O643.3
Type PhD thesis
Year 2001
Downloads 254
Quotes 4
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China has abundant resources of propane, from inexpensive propane acrolein synthesis of high value-added economic significance is self-evident. In addition, the selective oxidation of propane to acrolein contained in the intermediate orientation on how to promote into the target product and how to suppress the poor stability of acrolein further oxidation catalysis and other important scientific issues, therefore, be important to study the reaction The theoretical significance. So far, the selective oxidation of propane to acrolein reaction performance is not high, developed a better performance of the catalyst of the reaction yield of acrolein is generally about 10%, and usually at a low rate in the case of propane conversion to obtain high acrolein selectivity. Selective oxidation of propane to acrolein reaction mechanism is not clear, two possible reaction pathways through the intermediate product is propane propylene to acrolein, or after n-propoxy (n-propanol) intermediates acrolein. Selective Oxidation of Propane to Acrolein catalysts and catalytic reactions of many issues to be studied, such as catalyst structure and the relationship between the performance of the catalyst is unclear, especially the catalyst under reaction conditions (dynamic) between the structure and reactivity relationship; redox catalysts and pH effects on catalyst performance there is controversy: on the catalytic reaction mechanism less, there is not enough depth and meticulous research. For the selective oxidation of propane to acrolein in the above-mentioned problems, we developed a similar catalyst with better performance compared to the reaction Selective Oxidation of Propane to Acrolein over Ce-Ag-Mo-PO Catalysts, on this basis, with the XRD technique measured at different structure of the catalyst composition, with H 2 -TPR, O 2 -TPD, in situ LRS, EPR and XPS techniques investigated the oxidation catalysts with different compositions reduction with NH 3 -DRIFT, isopropanol characterize the cleavage reaction pH catalysts of different compositions discussed the possible nature of the catalyst into the reaction intermediate orientation of acrolein, which nature of the catalyst and catalyst performance relationship. Followed, using in situ LRS combined XRD, XPS and Catalyst Performance evaluation of the dynamic structure of catalyst, the catalyst discussed the causes and dynamic structure and reactivity relationships. Finally, the Ce-Ag-Mo-PO Catalysts on the selective oxidation of propane to acrolein reaction pathways Zhang listen Extensible Abstract studied. Therefore, evaluation of propane and propane selective oxidation to acrolein intermediates (intermediates) or probe molecules such as propylene, n-propanol, isopropanol, n-propyl Bin behalf, on behalf of isopropyl Creek, propionaldehyde, acetone etc. In the selective oxidation of propane to acrolein and under reaction conditions similar reactivity; and the use of confocal Raman spectroscopy investigation of propane, propylene, Yunnan propylene, allyl alcohol, n-propanol, isopropanol, n-propyl Bin generations , Bin behalf isopropyl, propionaldehyde, acetone, acrolein, formic acid, acetic acid, the Ce-Ag-MoI-O catalyst activation and conversions. Taking these experimental results, presented at the Ce-Ag-MoIO catalysts for selective oxidation of propane to acrolein possible reaction pathways. Detailed results are as follows: 1. Ce pair gMoI * Catalyst and reaction conditions on the catalyst performance under existing relevant selective oxidation of propane to acrolein catalyst composition, structure and reaction mechanism studies inspired choice M. And P element is the main component of the catalyst, and in the MO-P-O catalyst of the auxiliary added, the development of a Ce-Ag-Mo-P-O catalysts. The optimum reaction conditions in Koh (500 \A Chau O / P two l/3/10/6) catalysts for selective oxidation of propane to acrolein, get propane conversion rate of 15,3 W-propylene. an aldehyde selectivity was 28.7%, acrolein close was 4.4% of the results. Compared with a similar catalyst, Ce-Ag-MoI-O is a better catalytic performance of selective oxidation of propane to acrolein. 2.Ce-Ag-MOIo nature of the catalyst on the Catalyst comparative study of Ce-Ag-MoP0 catalyst and Ag-MoP-O catalyst structure, redox and pH to discuss the nature of the catalyst intermediate orientation on the impact of conversion to acrolein and catalytic propane the impact of selective oxidation of acrolein study found that adding the catalyst Ce, reaction intermediates may increase propylene and n-propoxy (n-propanol) directed into the ability of acrolein and catalytic selective oxidation of propane to acrolein reaction performance of the catalyst in the presence of the optimal range of the Ce content in Ce/Mo-0 * of Ce-Ag-MoP-O catalyst, Xiamen University Ph.D. thesis Zhang listen Extensible Abstract directed into the intermediate or propane acrolein higher selectivity With the increase of the content of Ce catalyst, the catalyst can be enhanced reduction, the Mo Bu / MoV ratio decreases, the catalyst surface acidity aluminum center, especially aluminum center L of the acidic catalyst surface decreased, which is due to: *) Ce and Mo catalysts occurred interact to form Mo \Of Mo (Mo 'spoon + CC' \and easy transfer of ions and facilitate the reduction of the catalyst in the process of the cationic high, so the reduction catalyst can be enhanced, the catalyst MO '+ / Md \\ reduced. Md \adding a certain amount in the catalyst of Ce, lower Mo \catalysts for selective oxidation of propane to acrolein ability. 3.CesAgMOo-O catalyst M. O species (multi-platinum radical) of the dynamic structure of the catalyst structure is a key factor affecting the performance of the catalyst, so rotten clear structure of the catalyst, especially catalysts under reaction conditions and catalyst structure and the dynamics of the relationship between performance, revealing the exact configuration of the reaction catalyst - effect relationship, the development of high-performance selective oxidation of propane?

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