Methanol amination over hydrothermally treated zeolites RHO and Modernite

Methylamines are important chemicals in many industrial processes. They have use as intermediates for the production of many compounds containing amino groups as well as being used on their own. The acid catalysed amination of methanol generally yields a thermodynamically controlled product distribu...

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Main Author: Van Steen, Linda Heather Callanan
Other Authors: O'Connor, Cyril T
Format: Doctoral Thesis
Language:English
Published: University of Cape Town 2017
Subjects:
Online Access:http://hdl.handle.net/11427/23806
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spelling ndltd-netd.ac.za-oai-union.ndltd.org-uct-oai-localhost-11427-238062020-12-10T05:11:11Z Methanol amination over hydrothermally treated zeolites RHO and Modernite Van Steen, Linda Heather Callanan O'Connor, Cyril T Van Steen, Eric Chemical Engineering Methylamines are important chemicals in many industrial processes. They have use as intermediates for the production of many compounds containing amino groups as well as being used on their own. The acid catalysed amination of methanol generally yields a thermodynamically controlled product distribution. The equilibrium distribution for mono-, di-, and trimethylamine (MMA, DMA, and TMA), at 325°C and a molar methanol to ammonia ratio of 1, is 17, 21, and 62 mol % respectively. The market demand, on the other hand, is for about 33, 53, and 14 mol % MMA, DMA and TMA. Industrially, methylamines are formed by the reaction of methanol or dimethyl ether and ammonia over amorphous silica-alumina. This process involves large separation and recycle units which are both costly and energy intensive as the separation requires azeotropic distillation at 15 bar. Methylamines can be formed over other solid acid catalysts with definite crystal structures, namely zeolites. While being more active than amorphous silica-alumina, most zeolites do not show improved selectivity. Catalysts, which have, however, been reported to show improved selectivity to DMA, include zeolites Rho, ZK-5 and Chabazite. In addition, certain forms of hydrothermally treated Mordenite can produce nonequilibrium product distributions. The performance of Rho can also be improved with hydrothermal treatment. The objectives of this study were briefly as follows. Firstly, the question was asked as to which of the catalysts studied, viz. Rho and Mordenite, was the most suitable for the methanol amination reaction. The second objective was to find the optimal performance achievable from any catalyst using hydrothermal treatment. The third, and possibly most important, objective was to propose reasons for the changes caused to each catalyst by hydrothermal treatment. 2017-02-01T10:45:50Z 2017-02-01T10:45:50Z 2000 2016-11-30T10:49:41Z Doctoral Thesis Doctoral PhD http://hdl.handle.net/11427/23806 eng application/pdf University of Cape Town Faculty of Engineering and the Built Environment Department of Chemical Engineering
collection NDLTD
language English
format Doctoral Thesis
sources NDLTD
topic Chemical Engineering
spellingShingle Chemical Engineering
Van Steen, Linda Heather Callanan
Methanol amination over hydrothermally treated zeolites RHO and Modernite
description Methylamines are important chemicals in many industrial processes. They have use as intermediates for the production of many compounds containing amino groups as well as being used on their own. The acid catalysed amination of methanol generally yields a thermodynamically controlled product distribution. The equilibrium distribution for mono-, di-, and trimethylamine (MMA, DMA, and TMA), at 325°C and a molar methanol to ammonia ratio of 1, is 17, 21, and 62 mol % respectively. The market demand, on the other hand, is for about 33, 53, and 14 mol % MMA, DMA and TMA. Industrially, methylamines are formed by the reaction of methanol or dimethyl ether and ammonia over amorphous silica-alumina. This process involves large separation and recycle units which are both costly and energy intensive as the separation requires azeotropic distillation at 15 bar. Methylamines can be formed over other solid acid catalysts with definite crystal structures, namely zeolites. While being more active than amorphous silica-alumina, most zeolites do not show improved selectivity. Catalysts, which have, however, been reported to show improved selectivity to DMA, include zeolites Rho, ZK-5 and Chabazite. In addition, certain forms of hydrothermally treated Mordenite can produce nonequilibrium product distributions. The performance of Rho can also be improved with hydrothermal treatment. The objectives of this study were briefly as follows. Firstly, the question was asked as to which of the catalysts studied, viz. Rho and Mordenite, was the most suitable for the methanol amination reaction. The second objective was to find the optimal performance achievable from any catalyst using hydrothermal treatment. The third, and possibly most important, objective was to propose reasons for the changes caused to each catalyst by hydrothermal treatment.
author2 O'Connor, Cyril T
author_facet O'Connor, Cyril T
Van Steen, Linda Heather Callanan
author Van Steen, Linda Heather Callanan
author_sort Van Steen, Linda Heather Callanan
title Methanol amination over hydrothermally treated zeolites RHO and Modernite
title_short Methanol amination over hydrothermally treated zeolites RHO and Modernite
title_full Methanol amination over hydrothermally treated zeolites RHO and Modernite
title_fullStr Methanol amination over hydrothermally treated zeolites RHO and Modernite
title_full_unstemmed Methanol amination over hydrothermally treated zeolites RHO and Modernite
title_sort methanol amination over hydrothermally treated zeolites rho and modernite
publisher University of Cape Town
publishDate 2017
url http://hdl.handle.net/11427/23806
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