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Enhancement in microporosity and catalytic activity on grafting silica and organosilica moieties in lamellar titanium phosphate framework

Paper ID Volume ID Publish Year Pages File Format Full-Text
43259 45960 2008 7 PDF Available
Title
Enhancement in microporosity and catalytic activity on grafting silica and organosilica moieties in lamellar titanium phosphate framework
Abstract

New silica-grafted analogs of lamellar semicrystalline titanium phosphate (sc-TiOP), silicotitanium phosphate (STP) and organic–inorganic hybrid silicotitanium phosphate (HSTP) have been synthesized under hydrothermal condition without the assistance of any template or structure-directing agent under acidic pH conditions. These materials were characterized by elemental analysis, powder XRD, field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), N2 sorption and spectroscopic studies. N2 adsorption studies revealed that the surface area increased significantly when the Si atoms were incorporated into the layered titanium phosphate framework. The surface area improves further with the grafting of organosilane moiety in HSTP material. Fourier-transformed infrared (FT IR), UV–vis and X-ray photoelectron spectroscopic (XPS) results suggested the presence of Si–O–P, Ti–O–Si bonds and octahedral coordination of Ti(IV) in these novel microporous materials. Si- and Si–CH2CH2–Si-grafted materials showed considerable enhancement in catalytic activity towards the liquid phase partial oxidation of styrene, α-methyl styrene, cyclohexene and acrylic acid using dilute H2O2 as an oxidant. These materials also showed excellent catalytic activity and selectivity in ammoximation of cyclohexanone to cyclohexanone oxime in the presence of aqueous ammonia and dilute aqueous H2O2 with reference to the silica-free sc-TiOP analogue.

Graphical abstractNew silica- and organosilica-grafted analogues of lamellar semicrystalline titanium phosphate (sc-TiOP) have been synthesized hydrothermally. N2 adsorption studies revealed that the surface area increased significantly when the Si- and Si–CH2CH2–Si-moieties were grafted into the titanium phosphate framework. These materials showed excellent catalytic activity and selectivity in epoxidation and ammoximation reactions using dilute aqueous H2O2 as an oxidant vis-à-vis sc-TiOP.Figure optionsDownload full-size imageDownload as PowerPoint slide

Keywords
Microporous materials; Titanium phosphate; Organic–inorganic hybrid materials; Partial oxidation; Ammoximation
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Enhancement in microporosity and catalytic activity on grafting silica and organosilica moieties in lamellar titanium phosphate framework
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 343, Issues 1–2, 1 July 2008, Pages 55–61
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us