کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
65564 48396 2014 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Stability and catalytic properties of porous acidic (organo)silica materials for conversion of carbohydrates
ترجمه فارسی عنوان
پایداری و خواص کاتالیزوری مواد سیلیس اسیدی متخلخل (متخلخل) برای تبدیل کربوهیدرات
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی کاتالیزور
چکیده انگلیسی


• Sulfonic acid-modified silica and organosilica catalysts were prepared.
• Yields up to 88% were obtained for the dehydration of fructose in DMSO at 120 °C.
• Increased hydrothermal stability was observed for hydrophobic organosilicas.
• Desilication under hydrothermal conditions was observed for functionalized silica.
• Although grafting enhances structural stability, hydrolysis of functionalities occurs.

Sulfonic acid-modified mesoporous SBA-15-type silica and hybrid organosilica catalysts were prepared using the co-condensation and grafting functionalization methods. The catalytic activity of these materials for fructose dehydration to 5-hydroxymethylfurfural was studied in aqueous medium and in DMSO. The prepared materials were characterized by XRD, SEM, elemental analysis, nitrogen physisorption and 29Si CP MAS NMR. Special focus was on evaluating the influence of the structural modification of the mesoporous catalysts on their stability under the conditions of catalytic conversion of carbohydrates. In aqueous medium all catalysts show very low activity and HMF selectivity. However, when the reaction is carried out in DMSO, HMF yields of up to 88% can be achieved with a minimum amount of sulfonic acid-modified catalyst. Among the materials tested, the hybrid organosilica-based catalyst shows the highest dehydration rate. It is demonstrated that pure silica-based catalysts degrade strongly under the catalytic conditions. The hydrothermal stability of the mesoporous catalysts is improved in the presence of organic moieties in their structure. The co-condensed organic–inorganic catalysts retain much better the mesoporosity and are less susceptible to the loss of catalytic functional groups anchored to their surface compared to their pure silica counterparts. The methodology for the introduction of functional groups has also a profound impact on the catalyst stability. Species incorporated into the catalysts via the direct co-condensation method show much higher stability than those introduced via a post-synthetic grafting procedure.

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ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Molecular Catalysis A: Chemical - Volumes 388–389, July 2014, Pages 81–89
نویسندگان
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