Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Determination of acid sites in solid catalysts by mass spectrometry (1994)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 8 (1994), S. 599-602 
    Details
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: This paper reports a temperature-programmed desorption mass spectrometry method for determining the nature, number and distribution, according to relative strength, of acid sites in solid catalysts. By using pyridine as the titrant, the overall, Brönsted (B) and Lewis (L) acidities are determined. The Brönsted acidity is obtained individually by titration with 2,6-dimethylpyridine, whereas the Lewis acidity is calculated by difference. The desorption temperatures for the amines are used as measures of the relative strengths of the different types of acid sites. The results obtained are compared with those provided by a UV-visible spectrophotometric method reported elsewhere (J. M. Campelo et al., Can. J. Chem. Vol. 61, p. 544 (1983)).
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/rcm.1290080806
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Contribution of mass spectrometry to the determination of basic sites in solid catalysts (1995)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 9 (1995), S. 193-198 
    Details
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: This paper reports a new thermal programmed desorption-mass spectrometry (TPD-MS) method for determining the number and relative strength distribution of basic sites in solid catalysts using CO2 as titrant. The overall desorbed CO2 area is proportional to the total basicity, while the number of peaks and their maximum temperature (Tmax) are related to the particular type of basic site and its strength. The activation energy for CO2 desorption from various basic sites in each catalyst was calculated via TPD-MS experiments conducted at a variable heating rate for each catalyst, using the Kissinger equation. Diffuse reflectance infrared analysis of the bands at 2000-1000 cm-1 for CO2 adsorbed on various catalysts allows one to elucidate the nature of the chemical species involved, which depends on the particular type of site. The total basicity results obtained are compared with those provided by an existing spectrophotometric method using benzoic acid (pKa=4.19) as titrant.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/rcm.1290090303
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...