TR Dizin İndeksli Yayınlar / TR Dizin Indexed Publications Collection

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Department: search.filters.department.İzmir Institute of Technology. Chemical EngineeringInstitution Author: search.filters.institutionAuthor.Aykaç, Hilal

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  • Article
    Citation - WoS: 9
    Citation - Scopus: 10
    Hydrogenation of Citral Over Ni and Ni-Sn Catalysts
    (TUBITAK, 2008) Aykaç, Hilal; Yılmaz, Selahattin
    Liquid phase citral hydrogenation over zeolite-supported monometallic Ni and bimetallic Ni-Sn catalysts was studied. The zeolite support materials were Na-Y, Na-mordenite, and clinoptilolite. Ni and Sn contents of the monometallic and bimetallic catalysts were 8.1-9.2 wt% and 0.46 wt%, respectively. The type of the zeolite support affected the activity and selectivity of the catalysts differently. The main product of the citral hydrogenation reaction was citronellal, for both monometallic (84.5% yield) and bimetallic (44.5% yield) catalysts. The addition of promoter increased the selectivity to unsaturated alcohols (geraniol+nerol), i.e. it changed from 0.9% to 6.3% over mordenite and from 0.9% to 2.1% over Na-Y-supported catalysts. Furthermore, activity of the Ni catalysts decreased while the quantity of acetal remained almost constant. Intimate contact between active metal, promoter, and support, and a catalyst with a high concentration of weak acid sites gave high selectivity to geraniol+nerol.
  • Article
    Citation - WoS: 3
    Citation - Scopus: 3
    Hydrogenation of Citral Over Pt and Pt-Sn Catalysts
    (TUBITAK, 2008) Aykaç, Hilal; Yılmaz, Selahattin
    Hydrogenation of citral on monometallic (Pt) and bimetallic (Pt-Sn) catalysts was investigated. It was found that the catalyst activities and product distributions were different over Na-Y and Clino supports. Among monometallic catalysts, Pt/Na-Y was more selective to citronellol (3.9%) and unsaturated alcohols, geraniol and nerol, (14.1%). Sn addition increased the catalyst activities. However, its effect on product distribution differed. Yield of geraniol+nerol changed from 5.1% to 19.7% over Clino. However, selectivity to unsaturated alcohols over Na-Y decreased when it was prepared as a bimetallic catalyst support. Unsaturated alcohol formation was favored when there was a metal support interaction over monometallic catalysts, and metal-promoter interaction over bimetallic catalyst.