کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
61581 47589 2012 12 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Selective catalytic hydroalkylation and deoxygenation of substituted phenols to bicycloalkanes
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی کاتالیزور
پیش نمایش صفحه اول مقاله
Selective catalytic hydroalkylation and deoxygenation of substituted phenols to bicycloalkanes
چکیده انگلیسی

Phenol and substituted phenols are hydroalkylated and hydrodeoxygenated to bi-cycloalkanes in a tandem reaction over Pd nanoclusters supported on a large-pore molecular sieve HBEA at 473–523 K using water as solvent. The HBEA-supported Pd catalyst (metal–acid ratio: 1:22 mol/mol) optimally balances the competing rates of metal catalyzed hydrogenation as well as of solid acid-catalyzed dehydration and carbon–carbon coupling to combine hydrodeoxygenation and dimerization of phenol derivatives to C12–C18 bicycloalkanes in a single reaction sequence. A detailed kinetic study of the elementary reactions of (substituted) phenol and their potential products (cyclohexanol, cyclohexanone, and cyclohexene) demonstrates that phenol selectively reacts with the in situ generated cyclohexanol or cyclohexene on Brønsted acid sites. The acid-catalyzed alkylation of phenol with alcohol intermediates and alcohol dehydration are parallel reactions, which are subtly influenced by the competing hydrogenation reactions as well as by the presence of water as solvent. IR spectroscopy of adsorbed species and preliminary molecular modeling indicate that phenol and cyclohexanol enrichment in the large pores of zeolite HBEA is critical for the high activity and hydroalkylation selectivity.

Phenol and substituted phenols are hydroalkylated and hydrodeoxygenated to bi-cycloalkanes in a tandem reaction over Pd nanoclusters supported on a large-pore molecular sieve HBEA at 473–523 K using water as solvent. The HBEA-supported Pd catalyst (metal–acid ratio: 1:22 mol/mol) optimally balances the competing rates of metal catalyzed hydrogenation as well as of solid acid-catalyzed dehydration and carbon–carbon coupling to combine hydrodeoxygenation and dimerization of phenol derivatives to C12–C18 bicycloalkanes in a single reaction sequence.Figure optionsDownload high-quality image (120 K)Download as PowerPoint slideHighlights
► A method has been developed on highly selective hydroalkylation and deoxygenation of substituted phenols in water.
► The acid-catalyzed alkylation and alcohol dehydration are parallel reactions in phenol hydroalkylation.
► Such competition is subtly influenced by hydrogenation and the presence of water.
► The phenol and cyclohexanol enrichment in zeolite HBEA is critical for the high activity and hydroalkylation selectivity.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Catalysis - Volume 288, April 2012, Pages 92–103
نویسندگان
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