Determination of Integrated Molar Extinction Coefficients for Infrared Absorption Bands of Pyridine Adsorbed on Solid Acid Catalysts

Zeolites with MWW topology (MCM-22, ITQ-2 and MCM-36) exchanged with copper and iron were studied as catalysts for selective catalytic reduction of NO with ammonia. It was shown that delamination and pillaring of layered MCM-22 zeolite resulted in the formation of ITQ-2 and MCM-36, respectively. Both these materials were characterized by MWW topology and significant contribution of mesopores.In a series of the zeolite based catalyst the most promising results in a process of selective catalytic reduction of NO with ammonia were obtained for the copper doped samples (Cu-MCM-22 and Cu-ITQ-2), however catalytic performance of the studied catalytic systems strongly depends on type, content and form of deposited transition metal species. Moreover, both these catalysts were found to be catalytically stable in the DeNOx process after hydrothermal treatment.2

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“…All the spectra were scaled according to the sample weight. Absorption coefficients calculated by Emeis [23] were used.…”

Section: Catalysts Characterizationmentioning

confidence: 99%

Cu and Fe modified derivatives of 2D MWW-type zeolites (MCM-22, ITQ-2 and MCM-36) as new catalysts for DeNO x process

Rutkowska

Díaz

Palomares

et al. 2015

Applied Catalysis B: Environmental

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“…4. All samples calcined at different temperatures exhibit an intense band at 1,445 cm -1 and three bands at 1,577, 1,593, and 1,613 cm -1 , which are generally assigned to the Lewis acid sites [17]. With increasing the calcination temperature, [17], evidencing the absence of Brönsted acidity on the resulting c-Al 2 O 3 samples.…”

Section: Properties Of Pseudoboehmite and Effect Of Peptizing Agentmentioning

confidence: 90%

“…All samples calcined at different temperatures exhibit an intense band at 1,445 cm -1 and three bands at 1,577, 1,593, and 1,613 cm -1 , which are generally assigned to the Lewis acid sites [17]. With increasing the calcination temperature, [17], evidencing the absence of Brönsted acidity on the resulting c-Al 2 O 3 samples. The absence of Brönsted acid sites on the calcined alumina samples may be ascribed to the relatively high temperature (550°C) employed for the calcination and the low thermal stability of the hydroxyls on unmodified alumina samples, which resulted in the high degree of dehydroxylation.…”

Section: Properties Of Pseudoboehmite and Effect Of Peptizing Agentmentioning

confidence: 90%

A comparative study of different fluorine-containing compounds in the preparation of novel alumina binders with rich Brönsted acid sites

et al. 2014

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Alumina is commonly used as a catalyst binder together with aluminum sol in modern fluid catalytic cracking (FCC) catalysts. The surface acidity properties of alumina strongly affect the catalytic performance of FCC catalysts. Lewis acid sites tend to produce coke because of their dehydrogenation activity, while Brönsted ones produce less coke. Thus, it is beneficial to convert the surface Lewis acid sites into Brönsted type. Fluorine-containing modifiers have been demonstrated to be effective to generate Brönsted acid sites on alumina surface. However, different types of fluorine-containing compounds may have different modification effects. In this work, three fluorinecontaining compounds, ammonium fluoroborate (NH 4 BF 4 ), ammonium fluorosilicate [(NH 4 ) 2 SiF 6 ], and ammonium fluoride (NH 4 F), were tested and compared in the modification of alumina surface acidity. Results show that NH 4 BF 4 and (NH 4 ) 2 SiF 6 perform equally well in the generation of Brönsted acid sites, while NH 4 BF 4 is more effective in the reduction of Lewis acid sites. In comparison, NH 4 F is not so effective in the generation of Brönsted acid sites as the other two compounds.

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“…The SiO 2 /Al 2 O 3 mole ratio was 20 and the Al content was 1.6 mmol/g. Acid sites (Table 2) were measured by IR analysis of pyridine absorption at 250 • C according to the procedure described in the literature [15].…”

Section: Methodsmentioning

confidence: 99%

Co-production of butyrate methyl ester and triacetylglycerol from tributyrin and methyl acetate

Battistel

Calaprice

Gualdi

et al. 2011

Applied Catalysis A: General

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a b s t r a c tThe simultaneous synthesis of butyric acid methyl ester, the shortest component of the FAME (fatty acid methyl esters) family, and glycerol triacetate (TAG) from glycerol tributyrate (tributyrin) and methyl acetate was studied as a function of several reaction parameters, such as type of catalyst, temperature and products distribution. The reaction is an interesterification, a multistep consecutive ester interchange catalyzed by either acid or base catalyst. Under optimized conditions, a complete tributyrin conversion and an almost quantitative butyric acid methyl ester accumulation were achieved. The other reaction product, TAG, formed by the complete acetylation of the glycerol moiety, reached almost 70% yield, whereas the mono-and di-acetylated intermediates accumulated in the order of 5-8% and 24-27%, respectively. Similar final conversions and products yields were obtained with either acid or base homogeneous catalysts, suggesting that the final products mixture did not depend on the type of catalysis but might be limited by equilibrium conditions. In spite of similar final yields, base catalysis needed shorter reaction times (minutes instead of hours) and lower temperature (60 • C instead of 130 • C) with respect to the best acid catalyst. On the other hand, unlike heterogeneous basic catalysts, which showed low activity, a heterogeneous acid catalyst almost as active as the homogenous counterpart was found.

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Determination of Integrated Molar Extinction Coefficients for Infrared Absorption Bands of Pyridine Adsorbed on Solid Acid Catalysts

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Cu and Fe modified derivatives of 2D MWW-type zeolites (MCM-22, ITQ-2 and MCM-36) as new catalysts for DeNO x process

Cu and Fe modified derivatives of 2D MWW-type zeolites (MCM-22, ITQ-2 and MCM-36) as new catalysts for DeNO x process

A comparative study of different fluorine-containing compounds in the preparation of novel alumina binders with rich Brönsted acid sites

Co-production of butyrate methyl ester and triacetylglycerol from tributyrin and methyl acetate

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