AMMONIATION AND NITRIDATION OF HIGHLY DISPERSE SILICA

被引:26
作者
FINK, P
MULLER, B
RUDAKOFF, G
机构
[1] Institute of Physical Chemistry, Friedrich-Schiller-University Jena, O- 6900 Jena
关键词
D O I
10.1016/S0022-3093(05)80437-5
中图分类号
TQ174 [陶瓷工业]; TB3 [工程材料学];
学科分类号
0805 ; 080502 ;
摘要
Infrared spectroscopy, X-ray scattering intensity measurements and chemical analysis of the N content have been used to study the reaction of flowing NH3 with highly disperse silica (aerosil) at elevated temperatures. During interaction with flowing NH3 (ammoniation) at temperatures less-than-or-equal-to 723 K, only SiNH2 groups were formed by substitution of SiOH groups on aerosil. At temperatures higher than 773 K under flowing NH3, both SiNH2 groups and Si-NH-Si groups (silazane bridges) were formed, which could be identified clearly in the IR spectra. Silazane bridges appear at temperatures greater-than-or-equal-to 1073 K, replacing not only surface siloxane bridges but also siloxane bridges in the bulk. With increasing reaction time, nitrogen contents up to 25 mass% were introduced into the SiO2 lattice by a reaction of aerosil with flowing NH3 at 1373 K. X-ray scattering intensity measurements have shown that the incorporation of nitrogen in the aerosil structure gives rise to a drastic rearrangement of the amorphous SiO2 structure. Both the primary structure order and the mid-range order of the aerosil were strongly changed after high temperature ammoniation. The treatment of aerosil in flowing N2 at 1373 K results in formation of cristobalite.
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页码:99 / 104
页数:6
相关论文
共 12 条
[1]   CHEMISORPTION OF AMMONIA ON SILICA [J].
BLOMFIELD, GA ;
LITTLE, LH .
CANADIAN JOURNAL OF CHEMISTRY, 1973, 51 (11) :1771-1781
[2]  
Fink P., 1990, WISS Z F SCHILLER U, V39, P217
[3]  
FINK P, 1978, WISS Z FSU JENA MATH, V27, P691
[4]  
Fink P., 1988, WISS Z FRIEDRICHSCHI, V37, P911
[5]   QUANTITATIVE-DETERMINATION OF OH-GROUPS ON AEROSIL SURFACES BY ZINCDIMETHYL-2-TETRAHYDROFURAN [J].
HANKE, W .
ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE, 1973, 395 (2-3) :191-202
[6]   INFRARED STUDIES OF REACTIONS ON OXIDE SURFACES .4. STRUCTURE OF CHEMISORBED AMMONIA ON SILICA [J].
MORROW, BA ;
CODY, IA ;
LEE, LSM .
JOURNAL OF PHYSICAL CHEMISTRY, 1975, 79 (22) :2405-2408
[7]   INFRARED STUDIES OF REACTIONS ON OXIDE SURFACES .7. MECHANISM OF ADSORPTION OF WATER AND AMMONIA ON DEHYDROXYLATED SILICA [J].
MORROW, BA ;
CODY, IA ;
LEE, LSM .
JOURNAL OF PHYSICAL CHEMISTRY, 1976, 80 (25) :2761-2767
[8]   INFRARED STUDIES OF REACTIONS ON OXIDE SURFACES .5. LEWIS ACID SITES ON DEHYDROXYLATED SILICA [J].
MORROW, BA ;
CODY, IA .
JOURNAL OF PHYSICAL CHEMISTRY, 1976, 80 (18) :1995-1998
[9]   INFRARED STUDY OF SOME REACTIONS WITH REACTIVE SITES ON DEHYDROXYLATED SILICA [J].
MORROW, BA ;
CODY, IA .
JOURNAL OF PHYSICAL CHEMISTRY, 1975, 79 (07) :761-762
[10]   INFRARED STUDIES OF REACTIONS ON OXIDE SURFACES .6. ACTIVE-SITES ON DEHYDROXYLATED SILICA FOR CHEMISORPTION OF AMMONIA AND WATER [J].
MORROW, BA ;
CODY, IA .
JOURNAL OF PHYSICAL CHEMISTRY, 1976, 80 (18) :1998-2004