I have been wondering about the "corrosive" effects of ethanol for a time. It is certainly easy to understand that ethanol may have adverse effects on some polymeric or plastic articles, either through direct solvation or through the extraction over time of plasticizers and/or processing oils and aids. Such behavior can cause shrinkage of seals, etc.
But what really got me thinking about ethanol was throwing out a wine bottle the other day. It made me think of wine turning to vinegar through the oxidation of ethanol to acetic acid. There is no doubt that this is what can occur in gasoline with ethanol. And just think what adding a few drops of glacial acetic acid to your lawnmower gas tank would do over time...cause rust to form, eat through metal parts, form metal acetate salts that can clog up the orifices in small carburators. The list is probably endless. This is one reason that adding an antioxidant helps with ethanol containing gasoline. Stabil, usually with something similar to BHT, stops the oxidation until it is used up as a sacrificial material.
But what if some acetic acid does form? If you look at the additives in gas to keep valves clean, you find aminated materials (Shell "Nitrogen", for example). Acetic acid can form salts with amines and I am wondering if the use of these amine materials in gasoline are actually exacerbating the problems of ethanol oxidation? Such salts would be gummy, sticky and probably relatively insoluble in gasoline. What would dissolve them? Something quite polar like acetone, MEK, ethyl acetate, etc. This may be why something like Kreen works in gasoline.
Any thoughts would be welcome.
But what really got me thinking about ethanol was throwing out a wine bottle the other day. It made me think of wine turning to vinegar through the oxidation of ethanol to acetic acid. There is no doubt that this is what can occur in gasoline with ethanol. And just think what adding a few drops of glacial acetic acid to your lawnmower gas tank would do over time...cause rust to form, eat through metal parts, form metal acetate salts that can clog up the orifices in small carburators. The list is probably endless. This is one reason that adding an antioxidant helps with ethanol containing gasoline. Stabil, usually with something similar to BHT, stops the oxidation until it is used up as a sacrificial material.
But what if some acetic acid does form? If you look at the additives in gas to keep valves clean, you find aminated materials (Shell "Nitrogen", for example). Acetic acid can form salts with amines and I am wondering if the use of these amine materials in gasoline are actually exacerbating the problems of ethanol oxidation? Such salts would be gummy, sticky and probably relatively insoluble in gasoline. What would dissolve them? Something quite polar like acetone, MEK, ethyl acetate, etc. This may be why something like Kreen works in gasoline.
Any thoughts would be welcome.