Sunday, October 7, 2018

organic chemistry - How to test for methanol?


I wanted to make some ethanol from baker's yeast and I used sucrose. I've made it and put it in a glass jar. I left it on a warm place (near the radiator) until the yeast died and after they died I distilled the yellowish liquid using simple distillation. When I smelled the product in the receiving flask I was confused. It resembled ethanol a little. The smell was like sweet and medium-intense ethanol. I think that it might be methanol. If there are any reagents or tests other than smelling that I can use at home, please do tell.



Answer



Sorry @ JavaScriptCoder, but I've to agree with aventurin. I'd say idoform test should have been done in a certified laboratory because of safety concern. However, I think fractional distillation might be helpful for this identification (or simply verification). Adinex can do this at home since he/she has done simple distillation at home. Ethanol/water binary system give an azeotrope, which boils at 78.1 °C and gives 95 % ethanol. Methanol, on the other hand, make no azeotrope with water, and boils at 64.7 °C. The temperature range of 13.4 °C need only about ≤20 theoretical plates to separate. If you get first distillate below, say, 67 °C, then you got methanol or something other than ethanol. So, don't drink it.


For more information, read the Wikipedia page having Azeotrope tables.


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