Appeal No. 1996-3674
Application No. 08/451,826
least one element selected from the group consisting of silicon, aluminum, phosphorus and boron, which
catalysts are useful for producing dimethylamine (DMA) (col. 4, lines 44-58). Zeolite rho synthesized
+ + + +
in a Na-Cs form is converted to the H -form by exchanging the Na and Cs ions for NH ions and
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deammoniating by calcination at 400EC to 800EC (col. 6, lines 57-63). Zeolite H -rho which was+
further treated with tetraethylorothosilicate before calcination had improved selectivity for DMA (col.
14, line 47 - col. 15, line 22). Ammoniated zeolite chabazite is also converted to its H -form by+
calcination, generally from 400EC to 600EC (col. 8, lines 28-36). Modified zeolites are generally
calcined at various temperatures between 300EC to 800EC for 2 to 24 hours, depending upon the
element used to treat the zeolite (col. 12, lines 15-18; col. 13, lines 10-12 and 32-35). The zeolite
catalyst may also be combined with matrix materials, e.g., clays, silica and/or metal oxides, which are
resistant to the temperature or other conditions of a DMA production process (col. 17, lines 39-44).
Abrams discloses that calcining an acidic zeolite rho catalyst at a temperature of about 475EC
to about 825EC in the presence of steam provides a catalyst with higher activity and higher selectivity
for DMA (col. 4, lines 32-35 and 53-59). The catalyst may also be combined with matrix materials,
e.g., clays, silica, alumina, and other metal oxides, which are resistant to the temperature or other
conditions of a process for producing DMA (col. 13, lines 7-12; abstract).
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