| 1. |
- Konwar, Lakhya Jyoti, et al.
(författare)
-
Towards carbon efficient biorefining : Multifunctional mesoporous solid acids obtained from biodiesel production wastes for biomass conversion
- 2015
-
Ingår i: Applied Catalysis B. - : Elsevier. - 0926-3373 .- 1873-3883. ; 176, s. 20-35
-
Tidskriftsartikel (refereegranskat)abstract
- Multifunctional mesoporous solid acids were prepared by the sulfonation of carbonized de-oiled seed waste cake (DOWC), a solid waste from biodiesel production. Detailed structural characterization of the materials by elemental analysis, FT-IR, Raman, XRD, XPS, TGA, NH3-TPD and N-2-physisorption showed that they were structurally different from the carbohydrate and resin based sulfonated carbon catalysts. In addition to the typical -OH, -COOH and -SO3H groups they contain several N species (pyridinic, pyrrolic etc.) incorporated in their carbon frameworks. The basic structural unit of these materials is a flexible carbon nitride sheet which is extensively functionalized with acidic groups. Our results show distinct effects of raw material composition and preparation methods (activation, sulfonating agent etc.) on structure, stability, surface acidity and textural properties. Here, catalyst -SO3H density and porosity (pore size, pore volume and surface area) had a direct effect on activity. Also, H2SO4 was less useful than 4-BDS (4-benzenediazoniumsulfoante) as a sulfonating agent. The best catalysts with mesoporous structure (average pore diameter 3.9-4.8 nm, pore volume 0.28-0.46 cm(3) g(-1)) and -SO3H density (0.70-0.84 mmol/g(cat)) were obtained by 4-BDS sulfonation of chemically activated DOWCs. In contrast, hydrothermal H2SO4 sulfonation of DOWC produced a non-porous catalyst with high -SO3H density while those obtained by H2SO4 treatment of activated biomass (AC) had a porous structure with low -SO3H density (0.19 mmol/gcat). Furthermore, the reported catalysts show excellent activity in two reactions of interest in biomass conversion: cellulose saccharification (glucose yield 35-53%) and fatty acid esterification (conversion upto 97%) outperforming H2SO4, conventional solid acids (zeolites, ion-exchange resins etc.) as well as sulfonated carbons reported earlier works, confirming their potential as alternative environmentally benign solid catalysts for sustainable, carbon efficient biorefining.
|
|
| 3. |
- Virtanen, Pasi, et al.
(författare)
-
Modeling of Supported Ionic Liquid Catalysts Systems : From Idea to Applications
- 2017
-
Ingår i: Industrial & Engineering Chemistry Research. - : American Chemical Society (ACS). - 0888-5885 .- 1520-5045. ; 56:45, s. 12852-12862
-
Tidskriftsartikel (refereegranskat)abstract
- The modeling of chemical reactions studied in small scale, often carried out in Academia, is very important since it gives more information about the system and better possibilities to scale-up the processes in the future. Supported ionic liquid catalysts (SILCAs) have been studied in a number of different processes. However, the modeling of these processes have been studied only in a few cases. In this paper the sample cases are reviewed. These processes include hydrogenation of unsaturated aldehydes as well as isomerization of terpenes, α- and β-pinene oxides.
|
|
