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Facile evaluation of the crystallization and quality of the transient layered zeolite MCM-56 by infrared spectroscopy

Paper ID Volume ID Publish Year Pages File Format Full-Text
54354 47007 2015 7 PDF Available
Title
Facile evaluation of the crystallization and quality of the transient layered zeolite MCM-56 by infrared spectroscopy
Abstract

•IR spectroscopy can be used for monitoring MCM-56 formation and quality.•Skeletal vibrations of D6R units detect quantitatively the content of MWW.•Integrated intensity of D6R correlates with crystallinity, micropore volume and BAS concentration.

MCM-56 is a unique zeolite with MWW topology consisting of 2.5 nm thick mono-layers. It is formed as an intermediate converting into the 3D MWW zeolite, MCM-49. It is attractive for catalysis with well documented high activity for hydrocarbon conversions but as a transient product MCM-56 presents novel challenges with regard to synthesis and activation. This work describes application of IR spectroscopy to monitor MCM-56 formation by investigating solid products obtained at different times during hydrothermal synthesis with hexamethyleneimine as template. We identified a unique double band in the range 500–600 cm−1, which can be assigned to skeletal vibrations of D6R units, that appears upon formation of MWW framework and can be used for quantitative determination of its content in a sample. The integrated intensity correlates well with XRD crystallinity, micropore volume and Brønsted acid sites concentration. FTIR approach allows facile and fast measurement and therefore may complement and possibly supplant XRD and porosity for reliable quality control in the course of MCM-56 crystallization, e.g. for the purpose of rapid termination of the synthesis at ‘the optimal time’.

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Keywords
MWW zeolites; MCM-56 zeolite; IR spectroscopy; Skeletal vibrations
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Facile evaluation of the crystallization and quality of the transient layered zeolite MCM-56 by infrared spectroscopy
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Publisher
Database: Elsevier - ScienceDirect
Journal: Catalysis Today - Volume 243, 1 April 2015, Pages 39–45
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