TEMPERATURE-PROGRAMMED DESORPTION OF AMMONIA WITH READSORPTION BASED ON THE DERIVED THEORETICAL EQUATION

被引:154
作者
NIWA, M [1 ]
KATADA, N [1 ]
SAWA, M [1 ]
MURAKAMI, Y [1 ]
机构
[1] NAGOYA UNIV,SCH ENGN,DEPT APPL CHEM,CHIKUSA KU,NAGOYA,AICHI 46401,JAPAN
关键词
D O I
10.1021/j100021a056
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Temperature-programmed desorption (TPD) spectra were analyzed on the basis of the theoretical equation of TPD of ammonia with freely occurring readsorption, and two kinds of methods to determine the strength of zeolite acidity were proposed. The change of enthalpy upon desorption (Delta) was determined from the derived equation for the relationship between the temperature at the peak maximum and a parameter including the acid amount and the contact time of the carrier gas. The theoretical equation was confirmed experimentally not only from the precise determination of Delta H but also from an agreement between the values thus measured and those from microcalorimetry. Because the change of entropy upon desorption of ammonia (Delta S) was almost independent of the zeolite species, the constancy of Delta S was assumed; thus, Delta H was measured by a one-point experiment. Examples of determination of Delta H using this method were described. The proposed constant value of 150 J K-1 mol(-1) of Delta S was supported by thermodynamic considerations, Trouton's rule and entropy of ammonia. Because the simulated spectra based on the theoretical equation were similar to those obtained experimentally, a narrow distribution of zeolite acidity was expected.
引用
收藏
页码:8812 / 8816
页数:5
相关论文
共 21 条
[1]  
BARROW GM, 1988, PHYSICAL CHEM
[2]   TOPOLOGY AND MAXIMUM CONTENT OF ISOLATED SPECIES (AL, GA, FE, B, SI, ...) IN A ZEOLITIC FRAMEWORK - AN APPROACH TO ACID CATALYSIS [J].
BARTHOMEUF, D .
JOURNAL OF PHYSICAL CHEMISTRY, 1993, 97 (39) :10092-10096
[3]   STUDIES ON THE ACIDITY OF MORDENITE AND ZSM-5 .1. DETERMINATION OF BRONSTED ACID SITE CONCENTRATIONS IN MORDENITE AND ZSM-5 BY CONDUCTOMETRIC TITRATION [J].
CROCKER, M ;
HEROLD, RHM ;
SONNEMANS, MHW ;
EMEIS, CA ;
WILSON, AE ;
VANDERMOOLEN, JN .
JOURNAL OF PHYSICAL CHEMISTRY, 1993, 97 (02) :432-439
[4]  
Cvetanovic R., 1967, ADV CATAL, V17, P103, DOI DOI 10.1016/S0360-0564(08)60686-0
[5]   DESIGN PARAMETERS FOR TEMPERATURE-PROGRAMMED DESORPTION FROM A PACKED-BED [J].
DEMMIN, RA ;
GORTE, RJ .
JOURNAL OF CATALYSIS, 1984, 90 (01) :32-39
[6]   TEMPERATURE-PROGRAMMED DESORPTION STUDY OF AMMONIA DESORPTION DIFFUSION IN MOLECULAR-SIEVES .1. THEORY [J].
FORNI, L ;
MAGNI, E .
JOURNAL OF CATALYSIS, 1988, 112 (02) :437-443
[7]   DESORPTION-DIFFUSION OF AMMONIA IN MOLECULAR-SIEVES .4. DECATIONATED ZSM5 ZEOLITE [J].
FORNI, L ;
VATTI, FP ;
ORTOLEVA, E .
ZEOLITES, 1992, 12 (01) :101-106
[8]  
HAAG WO, 1994, STUD SURF SCI CATAL, V84, P1375
[9]  
JOSEFOWICZ LC, 1994, J PHYS CHEM-US, V98, P8053
[10]   INVESTIGATION OF THE DISTRIBUTION OF ACIDITY IN ZEOLITES BY TEMPERATURE-PROGRAMMED DESORPTION OF PROBE MOLECULES .1. DEALUMINATED MORDENITES [J].
KARGE, HG ;
DONDUR, V .
JOURNAL OF PHYSICAL CHEMISTRY, 1990, 94 (02) :765-772