Search

The modification of the physicochemical properties of synthetic zeolites is an important element when these materials are applied as heterogeneous catalysts in the view of more sustainable and effective processes. In this work, desilicated ZSM5 samples were tested on the methanol to dimethyl ether dehydration. Desilication time strongly affects the textural and acidic properties of the samples, and those characteristics determined a different catalytic behaviour. Contact time of 60 min with NaOH solution (alkaline desilication) favourably impact on the activity of the catalysts and its stability against deactivation in terms of methanol conversion and yield to DME, in comparison with parent zeolite and sample prepared after 30 min of desilication. This effect is due to a combination of changes in the properties of acidic sites and mesoporous volume, as confirmed by stability test over 80 h of reaction. The analysis of formed coke confirmed this evidence since the most performing catalyst showed the lowest tendency to form coke as the main consequence of the improved accessibility to the acid sites determined by the induced mesoporosity.

Methanol, or methyl alcohol, is the simplest alcohol, appearing as a colorless liquid with a distinctive smell. Nowadays, it is considered one of the most useful chemical compounds. In fact, it is one of the most promising building blocks for obtaining more complex chemical structures, such as acetic acid, methyl tertiary butyl ether, dimethyl ether, methylamine, etc. Furthermore, methanol is also considered a promising clean-burning fuel with a high octane number. Knowing that CO2 and H2 are among the precursors in methanol synthesis, it is noteworthy that the conversion of CO2 to methanol can be considered a promising method for significantly reducing CO2 emissions, and that methanol production can also be used as a convenient energy carrier for hydrogen storage and conservation. In fact, methanol synthesis is the second source, after ammonia production, of hydrogen consumption (which has the highest energy content per weight) via several reactions, such as partial oxidation, steam reforming, autothermal reforming, methanol decomposition, or methanol-water solution electrolysis. Finally, among the recent attractive applications of methanol, the most promising for the future are the production of DME, the production of hydrogen, and the direct methanol fuel cell (DMFC). This chapter is an overview of not only common feedstocks used in the production processes for obtaining methanol (natural gases, CO2, or char/biomass), but also of the historical production processes (such as the BASF process, also known as the “high-pressure method,” and the ICI process, also known as the “low-pressure method”) and the most innovative trends for industrial applications.