Determination of basic sites in Mg-Al mixed oxides by combination of TPD-CO2 and CO2 adsorption calorimetry

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216275%3A25310%2F17%3A39902701" target="_blank" >RIV/00216275:25310/17:39902701 - isvavai.cz</a>

Výsledek na webu

<a href="http://dx.doi.org/10.1007/s10973-016-5851-6" target="_blank" >http://dx.doi.org/10.1007/s10973-016-5851-6</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1007/s10973-016-5851-6" target="_blank" >10.1007/s10973-016-5851-6</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Determination of basic sites in Mg-Al mixed oxides by combination of TPD-CO2 and CO2 adsorption calorimetry

Popis výsledku v původním jazyce

We present the critical analysis of the utilization of CO2 adsorption calorimetry/volumetry and TPD-CO2 for the determination of the Mg-Al mixed oxide basicity. The aim of work is the description and the evaluation of both methods with respect to the fact when the same types of CO2 adsorption complexes are involved. Critical parts of basic sites determination are originally discussed for both methods. In TPD-CO2, the process of the purging of non-specifically physisorbed CO2 is stressed. In CO2 adsorption calorimetry, the differential heat of CO2 distinguishing CO2 adsorption on weak basic sites and non-specific CO2 physisorption is stressed. Both methods are applied on series of selected Mg/Al mixed oxides varying in Mg/Al molar ratio and alkali co-cation. We show that the generally used TPD-CO2 does not provide complete information about basic sites since some weak sites form unstable CO2 species and these species could not be involved in TPD experiments. All our TPD-CO2 experiments reflect at 0-485 A degrees C those CO2 adsorbed in the range of the differential heat of CO2 above 30-32 kJ mol(-1).

Název v anglickém jazyce

Determination of basic sites in Mg-Al mixed oxides by combination of TPD-CO2 and CO2 adsorption calorimetry

Popis výsledku anglicky

We present the critical analysis of the utilization of CO2 adsorption calorimetry/volumetry and TPD-CO2 for the determination of the Mg-Al mixed oxide basicity. The aim of work is the description and the evaluation of both methods with respect to the fact when the same types of CO2 adsorption complexes are involved. Critical parts of basic sites determination are originally discussed for both methods. In TPD-CO2, the process of the purging of non-specifically physisorbed CO2 is stressed. In CO2 adsorption calorimetry, the differential heat of CO2 distinguishing CO2 adsorption on weak basic sites and non-specific CO2 physisorption is stressed. Both methods are applied on series of selected Mg/Al mixed oxides varying in Mg/Al molar ratio and alkali co-cation. We show that the generally used TPD-CO2 does not provide complete information about basic sites since some weak sites form unstable CO2 species and these species could not be involved in TPD experiments. All our TPD-CO2 experiments reflect at 0-485 A degrees C those CO2 adsorbed in the range of the differential heat of CO2 above 30-32 kJ mol(-1).

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

20303 - Thermodynamics

Projekt

<a href="/cs/project/GA15-21817S" target="_blank" >GA15-21817S: Analýza vztahu mezi strukturou/basicitou Mg/Al, Ca/Al a Zn/Al směsných oxidů a jejich aktivitou v aldol kondenzaci a transesterifikaci</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2017

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Journal of Thermal Analysis and Calorimetry

ISSN

1388-6150

e-ISSN

—

Svazek periodika

127

Číslo periodika v rámci svazku

3

Stát vydavatele periodika

NL - Nizozemsko

Počet stran výsledku

9

Strana od-do

1921-1929

Kód UT WoS článku

000395082300007

EID výsledku v databázi Scopus

2-s2.0-84988731318