KMITL

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

Browse

Settings

Author: search.filters.author.Lobban, Lance L.

Search Results

Now showing 1 - 5 of 5
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Generation of reductive Zn species over Zn/HZSM–5 catalysts for n–pentane aromatization
    (2016-09-05)
    Tamiyakul, Sikarin
    ;
    Sooknoi, Tawan
    ;
    Lobban, Lance L.
    ;
    Jongpatiwut, Siriporn
    The effects of hydrogen treatment on Zn/HZSM–5 catalysts to the evolution of zinc species and their activity in n-pentane aromatization were studied. By heating Zn/HZSM–5 catalysts under inert atmosphere, most of zinc species appeared as (ZnOH)<sup>+</sup>. The XPS and IPA–TPD results showed that using H<inf>2</inf> as a treatment gas, the hydrodehydroxylation of (ZnOH)<sup>+</sup> generated (ZnH)<sup>+</sup> species with the recovery of some Brønsted acid sites. It was found that under the hydrogen atmosphere, the H<inf>2</inf> molecule was dissociated on this Zn species and generated the H<inf>2</inf>-chemisorbed Zn species. Compared with HZSM-5 catalyst, the presence of (ZnOH)<sup>+</sup> species improved the aromatics selectivity from 11% to 22%. Nevertheless, after pre-treating Zn/HZSM–5 with H<inf>2</inf>, the formation of H<inf>2</inf>-chemisorbed Zn species remarkably increased the BTX aromatics selectivity to 31%. It was found that the H<inf>2</inf>-chemisorbed Zn species was not stable in the absence of H<inf>2</inf> however it could be regenerated upon H<inf>2</inf> treatment.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Conversion of propylene and propanal on HZSM-5
    (2009-12-01)
    Hoang, Trung Q.
    ;
    Zhu, Xinli
    ;
    Sooknoi, Tawan
    ;
    Resasco, Daniel E.
    ;
    Lobban, Lance L.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Etherification of 2-methyl-pentanal on supported palladium
    (2009-12-01)
    Pham, Trung T.
    ;
    Crossley, Steven P.
    ;
    Sooknoi, Tawan
    ;
    Lobban, Lance L.
    ;
    Resasco, Daniel E.
    Dialkyl ethers can be selectively produced from etherification of 2-methyl-pentanal and other oxygenates on supported Pd catalysts. Selectivities of 90% of ether were observed when feeding 2-methyl-pentanal and 2-methyl-pentanol at a molar ratio 1:1. Yields of up to 79 % have also been achieved. The reaction appears to be sensitive to metal particle features and molar feed ratios.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Deoxygenation of model biofuel compounds over CsNaX zeolite catalyst
    (2008-12-01)
    Danuthai, Tanate
    ;
    Peralta, Maria A.
    ;
    Sooknoi, Tawan
    ;
    Osuwan, Somchai
    ;
    Lobban, Lance L.
    The deoxygenation of methyl octanoate and benzaldehyde over CsNaX zeolite catalyst has been investigated as a model for reactions for production of hydrocarbon fuels from bio-oxygenates. The CsNaX zeolite used in the study was prepared by ion exchange of NaX with a CsNO<inf>3</inf>/CsOH solution to a 50% exchange level. The decarbonylation activity, selectivity, and stability of the CsNaX catalyst were enhanced when methanol was co-fed for the reaction of methyl octanoate. TPD studies suggest that methyl octanoate first decomposes to an octanoate-like species. The decomposition of such species leads to the formation of heptenes and hexenes as major products. Octenes and hydrogenated products are formed in lesser amounts via hydrogenation / hydrogenolysis using hydrogen produced on the surface from methanol decomposition, but not from gas phase H<inf>2</inf>.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Adsolubilization and stability characteristics of hydrocarbon aggregates chemically bonded to porous silica
    (1997-08-20)
    Thakulsukanant, Chainarong
    ;
    Lobban, Lance L.
    ;
    Osuwan, Somchai
    ;
    Waritswat, Anchaleeporn
    The desorption of surfactant may be a problem in the development of admicellar catalysis for organic synthesis or for wastewater cleanup. The formation of hydrocarbon aggregates chemically bonded to mineral oxide surfaces has been investigated to solve this problem. In this study, octadecyltrichlorosilane (ODS) was chemically bonded with silanol groups of a silica surface. The adsolubilization capabilities and stability of the bonded ODS were then studied and compared to those of physically adsorbed aggregates of cetyltrimethylammonium bromide (CTAB). The adsorption of ODS increases with increasing ODS concentration in the bulk phase and reaches a constant value when the equilibrium ODS concentration is higher than 17 000 μM. The maximum ODS adsorption of 340 μmol/g is slightly higher than that of CTAB (300 μmol/g). The critical micelle concentration of CTAB is approximately 3000 μM. The adsolubilization of two organic substrates, trichloroethylene (TCE) and phenol, was also measured. The adsolubilization of TCE was similar in CTAB and bonded ODS, while the phenol adsolubilized to a greater extent in CTAB than in ODS. The bonded ODS was stable under agitation up to 310 rpm and temperatures below 40 °C. The pH value has very little effect on ODS debonding. The rate of oxidation of ODS by ozone increases with increasing ozone concentration, but pH has no effect on ODS oxidation.