KMITL

Permanent URI for this communityhttps://dspace.kmitl.ac.th/handle/123456789/1

Browse

Search Results

Now showing 1 - 7 of 7

Some of the metrics are blocked by your
consent settings
Xylenes production from renewable feedstocks
(2013-12-01)
Sooknoi, T.
;
Ausavasukhi, A.
Considerable efforts have been made during the past few years for utilizing renewable resources for chemical feedstock. As being ligno-cellulosic materials, biomass provides ready-to-use aromatic precursors for the production of xylene from biomassderived compounds. Typical approach involve fast-pyrolysis of the biomass followed by catalytic deoxygenation of the aromatic components (mainly the phenolics) in the "pyrolysis bio-oil" As the pyrolysis products always possess reactive oxygenates such as alcohols, aldehydes, and acids, the reaction requires a catalyst that readily promotes deoxygenation and/or dealkylation to form less substituted aromatic ring. Metals supported acidic oxides have been widely investigated for the reactions involving hydrogen (hydrogenation/ dehydrogenation and hydrogenolysis) and carbocation intermediates. Alternatively, refined biomass such as ethanol, fatty acid and glucose can also be converted to aromatic hydrocarbons. This approach involves dehydration, decarbonylation and/or decarboxylation to primarily produce olefinic or paraffinic hydrocarbons which can be subsequently converted to aromatic via classical acid catalysed processes. Shape selective feature of the zeolites always plays marked role for selective formation of xylenes for all approaches. This chapter will review recent attempts for xylene productions from renewable feedstock. The relation between the molecular architecture of the biomass-derived compounds and the selected catalyst system will be highlighted, together with the reaction conditions and possible on-going xylene production processes. © 2013 by Nova Science Publishers, Inc. All rights reserved.
Some of the metrics are blocked by your
consent settings
Aromatization of cyclopentane over ZSM-5 catalysts: A proposal of reaction pathway
(2012-06-19)
Peamaroon, N.
;
Sooknoi, T.
The conversion of cyclopentane over HZSM-5 and GaZSM-5 was studied at 500-600°C in a fixed bed flow reactor. The reaction over HZSM-5 showed that cyclopentane was first cracked to liquified petroleum gas (LPG) that consecutively aromatized to BTX and C<inf>9+</inf> aromatics. While over GaZSM-5, cyclopentane preferred to oligomerize to larger intermediate namely cyclic hydrocarbon pool that could be converted to C<inf>9+</inf> aromatics and then cracked to benzene toluene and xylene and LPG. The higher activity was obtained by lowering Si/Al ratio of the parent HZSM-5 and increasing reaction temperature. © 2012 Taylor & Francis Group, LLC.
Some of the metrics are blocked by your
consent settings
Selective ethylene-permeable zeolite composite double-layered film for novel modified atmosphere packaging
(2011-01-01)
Monprasit, P.
;
Ritvirulh, C.
;
Sooknoi, T.
;
Rukchonlatee, S.
;
Fuongfuchat, A.
The composite double-layered films, for the packaging application of postharvest fruits and vegetables, were prepared by laminating low-density polyethylene (LDPE) and poly[styrene-b-(ethylene-co-butylene)-b-styrene] (SEBS) modified with zeolite ZSM-5. The film was characterized by scanning electron microscope and differential scanning calorimeter and tested for permeation of ethylene (C<inf>2</inf>H<inf>4</inf>), oxygen (O<inf>2</inf>), carbon dioxide (CO<inf>2</inf>), and water vapor. It was found that the C<inf>2</inf>H <inf>4</inf> permeability of the films was improved because of an enhanced adsorption of C<inf>2</inf>H<inf>4</inf> by the incorporated zeolite (0-10 wt%). The preconcentrated layer (zeolite/SEBS) leads to a higher C<inf>2</inf>H <inf>4</inf> concentration gradient across the film. Moreover, the high dispersion of zeolite increased the C<inf>2</inf>H<inf>4</inf> permeation. When compared with O<inf>2</inf> and CO<inf>2</inf>, the composite films were more selective to C<inf>2</inf>H<inf>4</inf>. However, the C<inf>2</inf>H<inf>4</inf> permeation decreased in the presence of O<inf>2</inf> because of a competitive adsorption. In addition, the films possessed appreciate tensile properties for packaging application. Copyright © 2009 Society of Plastics Engineers.
Some of the metrics are blocked by your
consent settings
Oligomerization of propionaldehyde on novel basic catalysts
(2008-12-01)
Amen, Q. V.
;
Sooknoi, T.
;
Lobban, L. L.
;
Mallinson, R. G.
;
Resasco, Daniel E.
Vapor-phase oligomerization of propanal to 2-methyl-2-pentenal and 2-ethyl-3,5-dimethylcyclo-2-pentenone over basic zeolite catalysts (NaX, KNaX, KX, and CsNaX), as well as more traditional solid basic catalysts (MgO and MgO-Al2O3 hydrotalcites), was studied in an integral flow reactor at atmospheric pressure. Conversion and carbon yield based on catalyst properties (basicity, acidity) are reported. The highest stable activity was over KX, with the highest selectivity to the primary product, 2-methyl-2-pentenal (dehydrated aldol dimer of propanal) and the second highest selectivity to the secondary product, 2-ethyl-3,5-dimethylcyclo-2-pentenone (a non-aromatic cyclic trimer), with essentially no other products. Promotion of Zeolite X with various alkali metals also affected the acid and base site strengths, which had an effect on the conversion and selectivity.
Some of the metrics are blocked by your
consent settings
Tin oxide thin films deposited by ultrasonic spray pyrolysis
(2008-05-01)
Jadsadapattarakul, D.
;
Euvananont, C.
;
Thanachayanont, C.
;
Nukeaw, J.
;
Sooknoi, T.
This study investigated microstructure of SnO<inf>2</inf> thin films deposited by ultrasonic spray pyrolysis technique using 0.2 M of SnCl<inf>4</inf>·5H<inf>2</inf>O in absolute ethanol as a precursor. The deposition temperature (350-450 °C) and time (20-90 min) were varied. The influence of film-deposition conditions on grain size and orientation were discussed. The deposited SnO<inf>2</inf> films were textured polycrystalline films. The preferred orientation of SnO<inf>2</inf> films were quantitatively evaluated by texture coefficient (TC). The mean grain size and film thickness determined by SEM could be controlled over a range of 50-325 nm and 80-2690 nm, respectively.
Some of the metrics are blocked by your
consent settings
The influence of organic additives on the regioselectivity of oxygenation of alkanes with hydrogen peroxide in the presence of TS-1titanium silicalite
(2008-01-01)
Shul'pin, G. B.
;
Sooknoi, T.
;
Shul'pina, L. S.
Hydrogen peroxide oxidizes n-hexane, n-heptane, and n-octane at 50°C in the presence titanium silicalite TS-1 as a catalyst, forming isomeric mixtures of ketones and alcohols. Admixtures of organic acids, alcohols, benzene, and ethylbenzene sharply change the ratio of position isomers. For example, the normalized ratio is C(4): C(3): C(2) = 0.44: 1.0: 0.47 for n-heptane oxidation in the absence of additives, but it becomes 0.52: 1.0: 1.00 in the presence of benzyl alcohol and the addition of ethylbenzene changes it to 0.16: 1.0: 0.94. © 2008 MAIK Nauka.
Some of the metrics are blocked by your
consent settings
Synthesis, preparation and catalytic activities of V-doped TiO2 gel coating on porous α-Al2O3 beads
(2007-01-01)
Jaroenworaluck, A.
;
Panyathanmaporn, T.
;
Soontornworajit, B.
;
Supothina, S.
;
Tawkaew, S.
TiO<inf>2</inf> and V-doped TiO<inf>2</inf> gel were synthesized and coated onto porous α-Al<inf>2</inf>O<inf>3</inf> beads to study the thermal catalytic activities of oxidation reactions. Titanium isopropoxide (Ti(OPr) <inf>4</inf>) and 1,2-butadiol(Bu(OH)<inf>2</inf>) were used as starting chemicals for preparation of TiO<inf>2</inf> gel without V-doping. After aging at ambient temperature for one week, a TiO<inf>2</inf> gel was obtained. The concentration of Ti(OPr)<inf>4</inf> was varied, 0.2, 0.3, 0.7 and 2.4 M was used. For V-doping of the TiO<inf>2</inf> gel, 0.05, 0.20 and 0.75 mole% of V was prepared by ultrasonically dissolving vanadium acetylacetone (V(acac) <inf>2</inf>) in 1,2-butadiol. The solutions were then added to Ti(OPr) <inf>4</inf>. Finally, the mixed solutions were kept under ambient temperature for one week to form the V-doped TiO<inf>2</inf> gel. TiO<inf>2</inf> and V-doped TiO<inf>2</inf> were calcined at 300, 400, 500, 600, 700, and 800°C. XRD analysis, SEM and TEM in conjunction with EDS analysis were used to identify the phases present, grain size and morphology. The TiO<inf>2</inf> grains have a particle size in the nano-scale range. Doping TiO<inf>2</inf> with V could retard growth of the TiO<inf>2</inf> particles and affect phase transformation at higher calcination temperatures. Both the TiO<inf>2</inf> and V-doped TiO<inf>2</inf> gels were prepared and coated onto α-Al <inf>2</inf>O<inf>3</inf> beads to test oxidation reactions in a purpose-designed reactor. The results of the catalytic reactions indicated that V-doped TiO<inf>2</inf> had a higher oxidation activity than the undoped TiO<inf>2</inf> gel. The content of vanadium was related to the reaction efficiency.

KMITL

Browse

Filters

Settings

Sort By

Results per page

Search Results