Chemical Engineering / Kimya Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/14
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Article Citation - WoS: 13Citation - Scopus: 13Application of Work Function Measurements in the Study of Surface Catalyzed Reactions on Rh(1 0 0)(Taylor & Francis, 2018) Çağlar, Başar; Kızılkaya, Ali Can; Niemantsverdriet, J. W. (Hans); Weststrated, C. J. (Kees-Jan)The present article aims to show how work function measurements (WF) can be applied in the study of elementary surface reaction steps on metallic single crystal surfaces. The work function itself can in many cases not be interpreted directly, as it lacks direct information on structural and chemical nature of the surface and adsorbates, but it can be a powerful tool when used together with other surface science techniques which provide information on the chemical nature of the adsorbed species. We here, illustrate the usefulness of work function measurements using Rh(100) as our model catalyst. The examples presented include work function measurements during adsorption, surface reaction, and desorption of a variety of molecules relevant for heterogeneous catalysis. Surface coverage of adsorbates, isosteric heat of adsorption, and kinetic parameters for desorption, desorption/decomposition temperatures of surface species, different reaction regimes were determined by WF with the aid of other surface science techniques.Article Citation - WoS: 22Citation - Scopus: 23Acidic Sites in Beta Zeolites in Dependence of the Preparation Methods(Elsevier Ltd., 2004) Dimitrova, R.; Gündüz, Gönül; Dimitrov, L.; Tsoncheva, T.; Yılmaz, Selahattin; Urquieta-González, Ernesto AntonioBeta zeolites synthesized by different methods are compared in their structure peculiarities and acidic properties by nitrogen physisorption, IR-KBr, pyridine sorption-desorption and thermoprogrammed desorption of ammonia. It is found that mesopores could be obtained in beta zeolites with the change of the activation procedure. Methanol conversion to dimethyl ether and hydrocarbons is used as a test reaction for understanding of the acid center function.Conference Object Citation - WoS: 7Citation - Scopus: 8Acylation of 2-Methoxynaphthalene Over Ion-Exchanged Ss-Zeolite(Elsevier Ltd., 2002) Kantarlı, İsmail Cem; Artok, Levent; Bulut, Hatice; Yılmaz, Selahattin; Ülkü, SemraFriedel-Crafts acylation of 2-Methoxynaphthalene was carried out over various ion-exchanged β zeolites (Mn+β, where Mn+: In3+, Zn2+, Al3+, Fe3+, La3+) with various anhydride (acetic, propionic and benzoic anhydrides), or acyl chloride (acetyl, propionyl and benzoyl chlorides) acylating reagents. The results suggested that selectivity towards the 6-substituted products was higher with the larger size anhydrides, propionic and benzoic anhydrides. The metal cation type within the zeolite significantly influenced the extent of conversion and product distribution. That La3+ exchanged zeolite displayed higher selectivity for the 6-position acylated product with anhydrides ascribed mainly to narrowing of channels by the presence of La(OH)2+ ions that leave no room for the formation of more bulky isomeric forms and to enhanced Bronsted acidity of the zeolite. With acyl chlorides, the recovery of ketone products was found to be remarkably low. 1-Acyl-2-methoxynaphthalenes actively underwent deacylation when acyl chlorides were used as the acylation reagent.