Designing zeolite catalysts for shape-selective reactions: Chemical modification of surfaces for improved selectivity to dimethylamine in synthesis from methanol and ammonia

Corbin, David R.; Keane, Michael; Abrams, Lloyd; Farlee, R. D.; Bierstedt, P. E.; Bein, Thomas

doi:10.1016/0021-9517(90)90122-z

Cited by 32 publications

(2 citation statements)

References 15 publications

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“…Although a number of zeolites were tested, early results showed only a minor gain in selectivity toward MMA and DMA at MeOH conversions above 90%. − Over the past decade, however, substantial improvement was achieved through tailoring of the zeolite pores and their acidity. The selectivity by geometric constraints − and the chemical composition of a given molecular sieve were reported to markedly influence product distribution. ,− Ashina et al …”

Section: Introductionmentioning

confidence: 99%

Influence of the Chemical Composition upon Adsorption, Coadsorption, and Reactivity of Ammonia and Methanol on Alkali-Exchanged Zeolites

1996

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The interaction of ammonia and methanol with several alkali zeolites was studied by means of IR spectroscopy, mass spectrometry, and thermogravimetry. While ammonia adsorbed identically on all zeolites investigated, the adsorption complex of methanol subtly depended upon the concentration of lattice aluminum in the zeolite. This is attributed to the variation of the polarizability of the zeolite lattice induced by the varying chemical composition. With respect to the reaction of methanol with ammonia, the differences in the sorption of methanol led to variations in the reactivity of these zeolites toward the primary products monomethylamine and dimethyl ether. On zeolites with a high aluminum content, both products were formed in approximately equal concentrations, while with silicon-rich zeolites monomethylamine was the dominating product. With all alkali zeolites investigated methanol was significantly stronger adsorbed than ammonia.

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Section: Introductionmentioning

confidence: 99%

Influence of the Chemical Composition upon Adsorption, Coadsorption, and Reactivity of Ammonia and Methanol on Alkali-Exchanged Zeolites

1996

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“…The literature related to this process was reviewed recently by Corbin et al It is widely held that thermodynamic equilibrium favors the production of trimethylamine (TMA), whereas market demand is stronger for monomethylamine (MMA) and dimethylamine (DMA). As a consequence there have been many studies (e.g., refs , , , , , −24, and 29) seeking methods to alter the selectivity of the reaction system to favor MMA and DMA over TMA. Almost uniformly it has been assumed that the MAs are produced via a consecutive pathway (eqs 1−3), and the general approach has been to seek means to reduce the rate of TMA production without affecting the rates of MMA and DMA generation…”

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confidence: 99%

Preliminary Assessment of Membrane Reactors as a Means To Improve the Selectivity of Methylamine Synthesis

Sang¹,

Chang²,

Lund³

1999

Ind. Eng. Chem. Res.

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Methylamine synthesis from ammonia and methanol was studied using an amorphous silica−alumina catalyst. A combined thermodynamic and kinetic analysis shows that the selectivity ratio initially observed at high methanol conversion is a kinetic ratio, not a thermodynamic ratio. In some cases in the past this kinetic ratio has been taken to represent thermodynamic equilibrium. However, if the reaction is allowed to continue beyond the point where conversion of methanol and dimethyl ether is essentially complete, the product composition continues to change, albeit at a much lower rate. Eventually the thermodynamic selectivity ratio is obtained. A simple kinetic model was developed that captures this behavior, and this model was used to assess whether a membrane reactor might be used to alter the overall selectivity of methylamine synthesis. Four different membrane reactor configurations were considered. There were operational regimes where each configuration showed advantages, but these either occurred at low conversions or required extremely large reactors. These configurations are limited by currently available catalysts and membrane materials. The impact of membrane reactors could be increased with catalysts that retain high activity during methylamine disproportionation, i.e., after all methanol has been consumed. The development of membrane materials with better permselectivities would also increase the attractiveness of membrane reactor processes.

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The Interface of Nanoscale Inclusion Chemistry

Stucky

1992

Progress in Inorganic Chemistry

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Designing zeolite catalysts for shape-selective reactions: Chemical modification of surfaces for improved selectivity to dimethylamine in synthesis from methanol and ammonia

Cited by 32 publications

References 15 publications

Influence of the Chemical Composition upon Adsorption, Coadsorption, and Reactivity of Ammonia and Methanol on Alkali-Exchanged Zeolites

Influence of the Chemical Composition upon Adsorption, Coadsorption, and Reactivity of Ammonia and Methanol on Alkali-Exchanged Zeolites

Preliminary Assessment of Membrane Reactors as a Means To Improve the Selectivity of Methylamine Synthesis

The Interface of Nanoscale Inclusion Chemistry

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