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Friday, July 22, 2005

Production of Hydrogen by means of hydrogenation of ethanol

Along with the growing interest in Fuel Cell powered cars comes the need for higher production methods of Hydrogen, both in bulk form and in-car conversions (for fuels such as methanol and ethanol to be converted to hydrogen on board). Previous methods of converting Ethanol to hydrogen was by means of high-temperature steam reformation (at temperatures in excess of 600° C) to produce Hydrogen gas and CO.

This journal describes a special method of low-temperature dehydrogenation of ethanol over special Raney catalyst with Cu added to it. The first step produces one mole each of hydrogen gas and acetaldehyde (per mole of ethanol). This is followed by the decarbonylation of acetaldehyde to form methanol and CO. The whole reaction undergoes a water-gas shift to net one mole each of Methane and Carbon dioxide and two moles of Hydrogen.



Compared to high temperature reformation methods, which produces 6 moles of hydrogen per mole of ethanol, this reaction doesn't seem as fuel efficient, though the authors were confident, that with an internal combustion engine on-board that uses the methane produced as fuel, the total output energy would be equal.

Citeulike Link

3 Comments:

  • 6/10
    1) your title says that this is a hydrogenation reaction but in fact it is a dehydrogenation reaction
    2) I like the fact that it is a practical application of chemistry but it is probably too complicated an example on chemistry that we didn't examine in class.
    3) What I am looking for is a single reaction of one molecule converted to another with the reagents on the arrow, preferably of a reaction with covered in class. What you have put up is a sequence of reactions that don't add up and don't reflect the text (e.g. where is the methanol you mention?)

    By Blogger Jean-Claude Bradley, at 6:53 AM  

  • I'm an idiot...I meant to say Methane, not methanol

    By Blogger Erik the Viking, at 5:49 PM  

  • Try to post well before the next deadline so other students and I can comment before it gets graded.

    By Blogger Jean-Claude Bradley, at 4:11 PM  

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