Desorption, benzene, temperature programmed

Fig. 4 (a) Stepwise dehydrocyclization of -hexane (21, 62). (b) Temperature programmed desorption of benzene originating from various adsorbates over Pt-AljOs. Temperature of adsorption 25°C. Rate of heating 23°C per minute. Detector monopolar mass spectrometer, the ordinate corresponds to the I intensity of mass number 78, in arbitrary units. For clarity, the thermodesorption curves for other compounds (starting hydrocarbon) hexene from hexa-dienes and hydrogen have not been shown (62c). 

Figure 4 Temperature-programmed desorption/oxidation spectra for benzene, toluene, p-xylene, and mesitylene adsorbed on TiOi. (From Ref. 43.)...

Results of temperature-programmed desorption (TPD) of ammonia125 or argon126 were attributed to superacid sites. TPD of very weak bases such as substituted benzenes has been used successfully to compare the superacid character of a series... 

The porous structure of active carbons can be characterized by various techniques adsorption of gases (Ni, Ar, Kr, CO ) [5.39] or vapors (benzene, water) [5,39] by static (volumetric or gravimetric) or dynamic methods [39] adsorption from liquid solutions of solutes with a limited solubility and of solutes that are completely miscible with the solvent in all proportions [39] gas chromatography [40] immersion calorimetry [3,41J flow microcalorimetry [42] temperature-programmed desorption [43] mercury porosimetry [36,41] transmission electron microscopy (TEM) [44] and scanning electron microscopy (SEM) [44] small-angle x-ray scattering (SAXS) [44] x-ray diffraction (XRD) [44]. 

Fig. 1.9 Temperature-programmed desorption (TPD) of (a) hydrogen and (c) benzene from acetylene on clean Pd(lll) compared with the spectra for (b) hydrogen and (d) benzene from ethyUdyne-covered Pd(l 11). (With kind permission from Springer Science and Business Media.)...

In Part 1(1) the temperature programmed desorption (tpd) of n-hexane and n-octane from the (Na, H) forms for ZSM-5, ZSM-11 and Theta-1 was reported. In Part 11(2) the tpd of p-xylene and benzene from the same zeolite samples was presented. In the latter study the desorption of p-xylene from ZSM-5 and ZSM-11 zeolites of varying Si/Al ratio was also included. In the present study the effect of different cations in the channels and intersections of ZSM-5, ZSM-11 and Theta-1 on the desorption of n-hexane is reported. 

Crystalline borosilicate molecular sieves have been the object of an intensive investigation effort since they were reported in the open literature at the Fifth International Conference on Zeolites by Taramasso, et al. (1) A wide range of structures containing framework boron have been synthesized. The physical properties of these borosilicate molecular sieves have been studied by such techniques as X-ray diffraction, infrared and nuclear magnetic resonance spectroscopies, and temperature programmed desorption of ammonia. In addition, the catalytic performance of borosilicate molecular sieves has been reported for such reactions as xylene isomerization, benzene alkylation, butane dehydroisomerization, and methanol conversion. This paper will review currently available information about the synthesis, characterization, and catalytic performance of borosilicate molecular sieves. 

Yee A, Morrison SJ, Idriss H. A study of ethanol reactions over Pt/Ce02 by temperature programmed desorption and in situ FT-IR spectroscopy evidence of benzene formation. J Catal. 2000 191 30. 

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