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Synthesis, characterization and catalytic performance of titania supported VPO catalysts for the ammoxidation of 3-picoline

Paper ID Volume ID Publish Year Pages File Format Full-Text
41621 45895 2011 11 PDF Available
Title
Synthesis, characterization and catalytic performance of titania supported VPO catalysts for the ammoxidation of 3-picoline
Abstract

Series of vanadium phosphorus oxide (VPO) catalysts supported over titania (anatase) were synthesised with varying contents of VPO (5–50 wt%). These solids were characterised by ICP-OES, TG/DTA, BET, XRD, FTIR (Py-ads) and XPS. The catalytic activity was evaluated for ammoxidation of 3-picoline (3-pic) to nicotinonitrile (NN) in a fixed bed catalytic reactor. Thermal analysis provided good hints on the phase transformation of VHP precursor into active VPP phase at around 400 °C. BET surface areas and pore volumes are found to depend on VPO loading and varied in the range from 70 m2/g to 133 m2/g. XRD demonstrates the formation of (VO)2P2O7 (VPP) phase. XPS showed that an average oxidation state of vanadium around 4.0, which is found to be unaltered in the spent samples. FTIR (Py-ads) revealed the presence of both Lewis and Brønsted sites with varying proportions, which again depend upon VPO loading. Correlation of acidic properties (Lewis and Brønsted acid sites) of the catalysts with that of performance of catalysts was explored. VPO loading has a clear influence on the acidic properties and thereby catalytic activity and selectivity. Catalytic results showed that the supported catalysts gave better performance compared to bulk VPO. Yield of NN increased up to 20 wt% VPO loading and then decreased with further increase in VPO content. Among all catalysts tested, the 20 wt% VPO/TiO2 exhibited the best performance (X-3-pic = ca. 100% and Y-NN = 83%).

Graphical abstract. TiO2 supported VPO catalysts are found to be highly active and selective for the ammoxidation of 3-picoline to nicotinonitrile. Significantly high conversion of 3-picoline (X = ca. 100%) and high yield of nitrile (Y-NN = 83%) could be obtained over 20 wt% VPO/TiO2 catalyst.Figure optionsDownload full-size imageDownload high-quality image (28 K)Download as PowerPoint slideResearch highlights▶ Ammoxidation of 3-picoline to nicotinonitrile. ▶ Titania supported VPO catalyst are quite active and selective for this reaction. ▶ Varying VPO loading has strong influence on the performance of the catalyst. ▶ Acidity characteristics play key role on the catalyst properties. ▶ Conversion of 3-picoline ∼ 100% and the yield of NN = 80% were obtained.

Keywords
Ammoxidation; 3-Picoline; Nicotinonitrile; VPO catalysts; Acidity characteristics
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Synthesis, characterization and catalytic performance of titania supported VPO catalysts for the ammoxidation of 3-picoline
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 391, Issues 1–2, 4 January 2011, Pages 52–62
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
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