Oğuz Akpolat

Isomerization of α-pinene over ion-exchanged natural zeolites

Abstract Catalysts prepared by ion exchange of clinoptilolite-based natural zeolite tuffs with NH 4 + , Ba 2+ and Pb 2+ were investigated in the isomerization reaction of α-pinene at atmospheric pressure under nitrogen flow. Activity and selectivity to mono-, bi- and tricyclic products were correlated with acidity strength.

Investigation of heavy metal content in the suspended particulate matter and sediments of inner Gokova Bay and creeks.

The Bay of Gokova in Southeastern Aegean Sea (Turkey) is important by the potential of agricultural, municipal, and tourism activities. In addition, there is no industrial plant within the area in the Aegean Sea. Kadın Creek (Azmak) and Akçapınar Creek (Azmak) flowing into the inner Gokova Bay are one of the important factors in determining the character of the inner Gokova Bay. In this study, nine stations were selected in the inner Gokova Bay, Kadın Creek, and Akcapınar Creek. The concentrations of Cd, Cu, Fe, Pb, and Zn were measured in suspended particulate matter (SPM) and sediments. The samples of sediments and SPM were collected in between February 2008 and September 2008. The aim of the study is searching the change of concentrations of Cd, Cu, Fe, Pb, and Zn in suspended particulate matter and sediments in the inner Gokova bay, Kadın Creek, and Akçapınar Creek. It has been identified that the metal concentrations in the creeks are higher than the metal concentrations in the marine environment. It has also been observed that the concentrations of Pb, Cd, and Cu in summer season have been higher than in the winter season, but the concentrations of Fe and Zn have not shown a significant difference between in summer and winter seasons. The obtained results show that the some heavy metals are caused by the agricultural, municipal, and tourism activities operating in the coastal areas and terrestrial environment, and they are transported from the creeks to the Gokova Bay by suspended particulate matter.

Gas chromatographic analysis of alcohols in blood with a chemometric approach

The objective of the present study is to examine the main and interactive effects of different factors related with headspace-solid phase extraction (HS-SPME) and gas chromatography (GC) conditions for the simultaneous determination of alcohols (ethanol, methanol, isopropanol, n-propanol) and acetone in blood samples. In order to evaluate the simultaneous effects of the significant variables, a chemometric approach was utilized to reveal the important parameters. The factors affecting the headspace extraction of alcohols on the SPME fiber was first deduced in a screening study by applying a Plackett–Burman design. According to the screening results, the factors that possess a positive effect on peak areas are sample concentration, inlet temperature, flow rate for the carrier gas and volume of the solution. Based on the results of the screening study, to continue optimization, six insignificant values were fixed at the appropriate amounts (oven temperature: 50 °C; detector temperature: 250 °C; H2 gas flow rate: 35 mL min−1; split flow rate: 30 mL min−1; equilibrium temperature: 55 °C, extraction time: 4 min). Subsequently, a central composite design (CCD) was constructed for optimization and response surface methodology (RSM) was used to interpret the effect of each pair of independent variables on the response. The optimized method for alcohol and acetone analysis via HS-SPME-GC was validated through spike recovery tests.

Investigation of Isomerization Kinetics of m-Xylene Over Zeolite Based Catalysts

This chapter focuses on the shape selective catalysts, especially on ZSM-5 type zeolites, for the isomerization of m-xylene. The chapter discusses a novel catalyst that is selective for pxylene in the isomerization of m-xylene, to investigate the reaction mechanism and kinetics over the most selective catalyst using by a fixed bed catalytic reactor. In this work, gas-phase isomerization reaction of m-xylene was studied over various catalysts including Ni, Sn, Pt, Ga, Re or Zr in different amounts. Alumina and several types of zeolites have been employed as carriers. The catalysts prepared were characterized and the most selective catalyst was determined after a selectivity-screening test. The most selective catalysts were found to be the ones prepared over ZSM5 carriers and consisting of Ga and/or Pt as active components.