The n-butyl amine TPD measurement of Brönsted acidity for solid catalysts by simultaneous TG/DTG–DTA

Sasca, Viorel; Avram, Livia; Verdeş, Orsina; Popa, Alexandru

doi:10.1016/j.apsusc.2009.12.131

Cited by 21 publications

(20 citation statements)

References 32 publications

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“…S4 in Supplementary Material). This method was used previously by our research group for studying the acidities of the 12-tungstophosphoric acid and its Cs salts using the TPD of ethanol and TPD of n-butyl amines, [54,55] and for studying the acidities of different Cs salts of molybdophosphoric acid supported on SBA-15 using the TPD of ammonia [37].…”

Section: The Tpd Measurementsmentioning

confidence: 99%

Acidic nickel salts of Keggin type heteropolyacids supported on SBA-15 mesoporous silica

et al. 2015

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A series of heteropolyacids-mesoporous silica composites were prepared from nickel salt of molybdophosphoric acid Ni 1 HPMo 12 O 40 (NiHPM) by supporting on SBA-15 mesoporous silica in different concentrations of active phase. The structure and texture of these NiHPM/ SBA-15 composites were studied by XRD, FT-IR and micro-Raman spectroscopy, nitrogen physisorption at 77 K, UV-Vis-DRS and SEM-EDX. The effect of the support on thermal stability was investigated by TG-DTG, DTA and DSC methods. By impregnation of Ni salt on mesoporous silica the thermal stability of the Keggin structure increases in comparison with its parent bulk heteropolyacid. From XRD at small angles could be observed that NiHPM/SBA-15 composites with low surface coverage preserve the mesopore structure of silica, with well dispersed NiHPM on the surface of the pore walls for SBA-15. The adsorption of ammonia and its temperature programmed desorption using thermogravimetry were studied for acidity evaluation. The total acidity of the weak and strong acidic sites of NiHPM/SBA-15 composites is obviously increases in comparison with bulk Ni salt. The main products observed in the evolved gases during desorption of NH 3 were NH 3 , CO 2 and NO/ NO 2 .

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Section: The Tpd Measurementsmentioning

confidence: 99%

Acidic nickel salts of Keggin type heteropolyacids supported on SBA-15 mesoporous silica

et al. 2015

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“…About 20 mg samples were used for measurements using the alumina crucibles of 150 ll, respectively 900 ll for voluminous samples. The method was described by the authors in detail elsewhere by using the TPD of ethanol and TPD of n-butyl amines [33,34].…”

Section: Temperature Programmed Desorption (Tpd)mentioning

confidence: 99%

“…The adsorption of ethanol (Et-OH) and temperature programmed desorption procedure were recorded as the TG, DTG, DTA and T curves. As we mentioned in the experimental part, this method was used previously for studying the Brønsted acidities for the 12-tungstophosphoric acid and its Cs salts by using the TPD of Et-OH and TPD of n-butyl amines [33,34]. Thermal curves recorded during crystallization water removal and adsorption (at 573 K)/desorption of ethanol on 20Cs 1 PM-SBA15 composites are shown in Fig.…”

Section: The Tpd Of Ethanolmentioning

confidence: 99%

Adsorption–desorption and catalytic properties of SBA-15 supported cesium salts of 12-molybdophosphoric acid for the dehydration of ethanol

Popa

Sasca

Verdeş

et al. 2015

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Cesium salts of molybdophosphoric acid with varying amounts of the cations Cs 1 H 2 PMo 12 O 40 and Cs 3 PMo 12 O 40 have been prepared as pure or supported on SBA-15. The adsorption of ethanol and its temperature programmed desorption-TPD using thermogravimetry were studied for SBA-15 supported and unsupported Cs salts. The evolved gases during the adsorption-desorption of ethanol on CsHPM/ SBA-15 composites were identified by online mass spectrometry coupled with thermogravimetry. The main products observed in the evolved gases during the desorption of ethanol were C 2 H 4 , C 3 H 6 and unreacted ethanol. The amount of acidic sites of the composites was estimated by ammonia adsorption-desorption. The dehydration of ethanol was used to test the catalytic properties of the CsHPM samples incorporated on the silica matrix. SBA15-supported catalysts, appeared to be more active than bulk catalysts in vapor phase dehydration and dehydrogenation of ethanol reactions. The effect of the support leads to higher values of dehydration rates of ethanol as well as higher values of ethylene and acetaldehyde formation rates.

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“…A argila vermiculita possui propriedades importantes para catalisadores como alta resistência térmica e grande potencial para formação de sítios ácidos do tipo Brönsted, devido ao seu alto número de substituições tetraédricas [17][18][19][20] . O presente trabalho teve como objetivo avaliar a seletividade dos materiais obtidos por lixiviação seletiva da argila vermiculita frente à pirólise termocatalítica do PEBD, sendo os produtos principais hidrocarbonetos leves de maior valor de mercado.…”

Section: Introductionunclassified

Pirólise catalítica do PEBD usando como catalisador a vermiculita modificada

et al. 2016

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ResumoO polietileno de baixa densidade (PEBD) é um dos polímeros mais usados atualmente, e a grande quantidade desse polímero produzida resulta em toneladas de resíduos, que necessitam ser tratados. Neste trabalho foi realizada a pirólise termocatalítica do PEBD usando como catalisador a argila vermiculita modificada, como alternativa para o tratamento dos resíduos. A argila foi tratada com solução de ácido nítrico a diferentes concentrações e calcinada a 400 °C. Os materiais foram caracterizados por técnicas de difratometria de raios X, termogravimetria, adsorção de nitrogênio e espectroscopia de energia dispersiva. A pirólise térmica e termocatalítica foi realizada em um micro reator acoplado com GC/MS, a 500 °C. O intuito da pirólise de resíduos poliméricos é a obtenção de hidrocarbonetos leves (C<16), que possam ser empregados na indústria química e petroquímica, através de quebras na cadeia polimérica. Os resultados foram satisfatórios, com aumento no rendimento para hidrocarbonetos leves ao empregar os catalisadores chegando a 71,4% de produtos com C<16, enquanto a pirólise térmica resultou apenas de 25,8%. Palavras-chave: vermiculita, argila, pirólise, PEBD. AbstractLow density polyethylene (LDPE) is one of the most commonly-used polymers currently, and the great quantity of this polymer produced results in tons of waste that must be treated. We studied the thermocatalytic pyrolysis of LDPE with a modified clay vermiculite catalyst as an alternative for treatment of waste. The clay was treated with a solution of nitric acid at different concentrations and calcined at 400 °C. The materials were characterized by X-ray diffraction, thermogravimetry, nitrogen adsorption, and energy dispersive spectroscopy. Thermal and thermocatalytic pyrolysis were carried out in a microreactor coupled with GC/MS at 500 °C. The aim of the polymeric waste pyrolysis is the obtainment of light hydrocarbons (C<16), which can be used in the chemical and petrochemical industry, through breaks in the polymer chain. The results were satisfactory, with an increase in yield for light hydrocarbons by using catalysts reaching up to 71.4% of products with C<16, whereas thermal pyrolysis resulted in only 25.8%.

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The n-butyl amine TPD measurement of Brönsted acidity for solid catalysts by simultaneous TG/DTG–DTA

Cited by 21 publications

References 32 publications

Acidic nickel salts of Keggin type heteropolyacids supported on SBA-15 mesoporous silica

Acidic nickel salts of Keggin type heteropolyacids supported on SBA-15 mesoporous silica

Adsorption–desorption and catalytic properties of SBA-15 supported cesium salts of 12-molybdophosphoric acid for the dehydration of ethanol

Pirólise catalítica do PEBD usando como catalisador a vermiculita modificada

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