katarina Posted May 15, 2019 Share Posted May 15, 2019 Which reaction is true? Or maybe both?CH3OH + 2CuO = HCOOH + 2 Cu + H2OCH3OH + 2CuO = HCHO + Cu2O + H2OHow to explain this since the ratio of substrates in both reactions is the same. link removed Link to comment Share on other sites More sharing options...
DrP Posted May 15, 2019 Share Posted May 15, 2019 (edited) I'm guessing at the second one. I can't see the alcohol reducing the CuO back to the metal. The Cu1 going to Cu2 though looks feasible with the production of the ketone. I bet hypervalent_iodide will be able to explain why. Edited May 15, 2019 by DrP Link to comment Share on other sites More sharing options...
katarina Posted May 15, 2019 Author Share Posted May 15, 2019 Thank you Link to comment Share on other sites More sharing options...
DrP Posted May 15, 2019 Share Posted May 15, 2019 no problem... although I would check the reasoning behind it, I could be wrong. Also, sorry, it's formaldehyde not a ketone (which is very similar with the c=o) obviously. Link to comment Share on other sites More sharing options...
studiot Posted May 15, 2019 Share Posted May 15, 2019 (edited) Have you considered the solubilities (not necessarily in water) of cuprous v cupric oxides? eg in Fehling's solution/test. Edited May 15, 2019 by studiot Link to comment Share on other sites More sharing options...
hypervalent_iodine Posted May 15, 2019 Share Posted May 15, 2019 I’m not overly familiar with using copper in this way, but I believe that you would typically use CuO catalytically in the presence of O2 (rather than stoicheometrically) to give the aldehyde. I don’t think you would get the acid, but I am not 100% sure. Link to comment Share on other sites More sharing options...
DrP Posted May 15, 2019 Share Posted May 15, 2019 OK - Typing the LHS of the equation into google gives links only to the formaldehyde as a result from what I can see. I don't have time to read through the results, but if you type 'CH3OH + 2CuO ' into google there should be some reading for you... at first glance it's all giving the aldehyde as the product. Link to comment Share on other sites More sharing options...
studiot Posted May 15, 2019 Share Posted May 15, 2019 1 hour ago, DrP said: OK - Typing the LHS of the equation into google gives links only to the formaldehyde as a result from what I can see. I don't have time to read through the results, but if you type 'CH3OH + 2CuO ' into google there should be some reading for you... at first glance it's all giving the aldehyde as the product. Better to type in "methanol and cupric oxide" https://www.google.com/search?client=firefox-b&ei=NwvcXPe7AbHzxgOs8obgBA&q=methanol+and+cupric+oxide+&oq=methanol+and+cupric+oxide+&gs_l=psy-ab.3..0i22i30.152328.177874..181186...0.0..0.146.3558.37j6......0....1..gws-wiz.....0..0i67i70i251j0i67j0i131i67j0j0i131j0i10i67j0i13j0i8i7i30j0i13i30j33i22i29i30.9Pr9Xyq7Wh4 This gives lots of stuff including the comaprison of copper and chrome oxides as catalysts https://www.researchgate.net/publication/231366160_Complete_oxidation_of_ethanol_acetaldehyde_and_ethanolmethanol_mixtures_over_copper_oxide_and_copper-chromium_oxide_catalysts It does seem you have to heat the methanol over the oxide. Unfortunately so many sites these days want to collect personal data an put up a barrier until you agree. So I leave and never return. Link to comment Share on other sites More sharing options...
John Cuthber Posted May 15, 2019 Share Posted May 15, 2019 Hot copper oxide is used in classical chemical analysis to convert organic compounds to carbon dioxide and water. What mixture of products you get will depend on temperature, contact time, proportions and other stuff. Passing methanol vapour over hot copper (metal- not oxide) will produce formaldehyde. The commercial synthesis uses silver, rather than copper. Link to comment Share on other sites More sharing options...
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