Thermodynamic and kinetic aspects of surface acidity

Technical Report · Wed Jan 01 04:00:00 EST 1992

DOI:https://doi.org/10.2172/5569965· OSTI ID:5569965

Dumesic, J A

Our research in the general area of acid catalysis involves the characterization of solid acidity and the corresponding assessment of catalytic performance of acidic materials. Acid characterization studies are required to provide essential information about the type of acid site (i.e., Lewis versus Bronsted), the strength of the sites, and the mobility of molecules adsorbed on the acid sites. An accurate measure of acid strength is given by the heat of adsorption of a basic probe molecule on the acid site. A thermodynamic representation of the mobility of adsorbed species on these sites is given by the entropy of adsorption. Important techniques used in these acid site characterization studies include microcalorimetry, thermogravimetric measurements, temperature programmed desorption, infrared spectroscopy and solid state nuclear magnetic resonance. The combination of these acid site characterization studies with reaction kinetics measurements of selected catalytic processes allows the elucidation of possible relationships between surface thermodynamic and kinetic properties of acidic sites. Such relationships are important milestones in formulating effective strategies for the effective utilization of solid acid catalysts. Current work in this direction involves methylamine syntheses over various zeolites, and the basic probe molecules employed include ammonia, methanol, water and mono-, di- and tri-methylamines. 31 refs., 18 figs., 1 tab.

• Research Organization: Wisconsin Univ., Madison, WI (United States)
• Sponsoring Organization: DOE; USDOE, Washington, DC (United States)
• DOE Contract Number: FG02-84ER13183
• OSTI ID: 5569965
• Report Number(s): DOE/ER/13183-T1; ON: DE92011194
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ADSORPTION HEAT
AMINES
BROENSTED ACIDS
CALORIMETRY
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL ANALYSIS
CHEMICAL PREPARATION
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
DESORPTION
DEUTERIUM
DOCUMENT TYPES
ENTHALPY
ENTROPY
GRAVIMETRIC ANALYSIS
HYDROGEN COMPOUNDS
HYDROGEN ISOTOPES
INFRARED SPECTRA
INORGANIC ACIDS
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
ISOTOPES
KINETICS
LEWIS ACIDS
LIGHT NUCLEI
MAGNETIC RESONANCE
MATERIALS
METHYLAMINE
MINERALS
MOBILITY
MOLECULES
NITRIC OXIDE
NITROGEN COMPOUNDS
NITROGEN OXIDES
NUCLEAR MAGNETIC RESONANCE
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
PROGRESS REPORT
QUANTITATIVE CHEMICAL ANALYSIS
REACTION KINETICS
REDUCTION
RESONANCE
SILICATE MINERALS
SPECTRA
STABLE ISOTOPES
SYNTHESIS
THERMAL ANALYSIS
THERMAL GRAVIMETRIC ANALYSIS
THERMODYNAMIC PROPERTIES
ZEOLITES