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Catalytic abatment of styrene traces in polystyrene: A model study of styrene reaction with excess cumene

Paper ID Volume ID Publish Year Pages File Format Full-Text
47267 46465 2010 5 PDF Available
Title
Catalytic abatment of styrene traces in polystyrene: A model study of styrene reaction with excess cumene
Abstract

The conversion of styrene in the presence of cumene has been studied on a family of aluminosilicate acid catalysts. This study was part of a project aimed at the removal of styrene monomer traces in polystyrene (PS). The catalytic experiments were performed at 200 °C in a closed stirred tank reactor with 1.92 mmol styrene, 49.8 mmol cumene and 60 mL n-dodecane as solvent. The evaluated catalytic materials were faujasite and beta zeolites, and amorphous silica-aluminas with disordered or ordered mesoporosity. Four reaction paths are involved in the styrene conversion. A free-radical chain polymerization in the homogeneous phase is mostly sensitive in the presence of catalysts of low activity. The three other transformation routes are catalyzed by the acid sites of the materials: (1) hydrogen transfer between styrene and cumene to ethylbenzene and α-methylstyrene; (2) ring oligomerization of styrene to dimers and trimers; (3) alkylation of cumene by styrene into primary and secondary alkylates. The presence of acid sites is a prerequisite for the styrene transformation to occur on the materials. However, the key factor for the catalytic activity is the presence of a large mesoporous volume favoring the molecular traffic within the solid. Mesoporous silica-aluminas behave most favorably in this sense. As regards the distribution of products, a strong acid strength as well as the increase of the cumene/styrene molar ratio favor the alkylation pathway. There is a dark coloration of the reaction medium when carbocations are trapped within the micropores of zeolites. Among the catalysts investigated, the most attractive materials as regards activity, selectivity and a coloration of the solution are mesoporous silica-aluminas and, more preferably, those featuring an ordered porosity of the MCM-41 type.

Keywords
Styrene; Heterogeneous catalysis; Zeolites; Mesoporous silica-alumina; Polystyrene
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Catalytic abatment of styrene traces in polystyrene: A model study of styrene reaction with excess cumene
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis B: Environmental - Volume 98, Issues 3–4, 1 August 2010, Pages 224–228
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
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