Тип публикации: статья из журнала
Год издания: 2018
Идентификатор DOI: 10.17223/24135542/11/1
Ключевые слова: hydrolysis-oxidation, xylan, formic acid, bifunctional catalyst, heteropolyacid, ruthenium, hydrolysis-reduction, xylitol, гидролиз-окисление, гидролиз-восстановление, ксилан, муравьиная кислота, ксилит, бифункциональный катализатор, гетерополикислота, рутений
Аннотация: Проведено исследование одностадийного гидролиз-окисления и гидролиз-восстановления ксилана в муравьиную кислоту и ксилит соответственно. Гидролиз-окисление ксилана проведено в растворе бифункционального катализатора Mo-V-P гетерополикислоты (ГПК) Coo,6H3,sPMoioV2O40. Муравьиная кислота получена с выходом 42% при 120°С за 7 ч. ГидроПоказать полностьюлиз-восстановление ксилана выполнено в присутствии твердого бифункционального катализатора 1%Ru/Cs3HSiWi2O40 Максимальный выход ксилита составил 32% и был достигнут при 190°С и 10 ч. Gradually decreasing high-quality stocks of nonrenewable fossil resources neces-sitate creating technologies based on the processing of an alternative, renewable, environmentally friendly raw material, plant biomass (lignocellulose). One of the promising research areas in biomass transformation is the development of one-pot processes for the direct production of valuable chemicals from plant raw materials over bifunctional catalysts. The plant polysaccharide xylan, which is contained in ag-ricultural wastes such as corn cobs and sunflower husks, can be clearly identified as a promising raw material for its direct one-pot processing to chemicals. When a one-pot hydrolysis-oxidation process is used, xylan can be transformed into formic acid, which is a promising reducing agent and an alternative to molecular hydrogen. The transformation of the xylan via a one-pot hydrolysis-hydrogenation enables obtaining xylitol, known to be a sugar substitute in the food and pharmaceutical industries. The aim of this work was a systematic study of one-pot hydrolysis-oxidation and hydrolysis-hydrogenation processes of xylan into formic acid and xylitol, respectively, in the presence of promising bifunctional catalysts based on heteropoly acids. Hydrolysis-oxidation of xylan was studied in a solution of the bifunctional Mo-V-P heteropoly acid catalyst (HPA). The composition of the catalyst was Co0.6H3.8PMo10V2O40. The HPA was obtained from the stoichiometric mixture of V2O5, MoO3, H2O2, H3PO4, and CoCO3 precursors. The catalyst developed possessed both acidic and vanadium-bound oxidation catalytic centers. Transformations of the polysaccharide were carried out in an autoclave under hydrothermal conditions at temperatures of 100-120 °C and a 20 bar air mixture pressure. To obtain kinetic da-ta, samples of the reaction mixture were collected from the autoclave for HPLC and total organic carbon analysis. An optimal process temperature of 120 °C was deter-mined for the hydrolysis-oxidation reaction of xylan to formic acid. A 42% yield of formic acid was reached under the optimal conditions. The conversion of xylan to xylitol via the hydrolysis-hydrogenation process was studied in the presence of a solid bifunctional catalyst of ruthenium nanoparticles supported on an acidic support of cesium salt of Si-W heteropolyacid, 1% Ru/Cs3HSiW12O40. The transformation of xylan was carried out in a high-pressure autoclave under hydrogen atmosphere (50 atm) and at 160-190 °C temperatures. The catalyst testing enabled a 32% xylan yield under optimal conditions (190 °C and a reaction time of 10 h).
Журнал: Вестник Томского государственного университета. Химия
Выпуск журнала: № 11
Номера страниц: 6-22
ISSN журнала: 24135542
Место издания: Томск
Издатель: Национальный исследовательский Томский государственный университет