[Talitha]

Hi, I am looking into the possibility of converting a petrol engine to run on 90-95% cellulosic ethanol (or the highest percentage of ethanol possible). I know all the gaskets etc can be reformulated to withstand alcohols but what metals will not be corroded by ethanol?

I have read that ethanol is corrosive because of the water content, is this right? Because I found this, supposedly written by a chemist which seems to contradicts that,

  "Some metals such as magnesium and possibly aluminium alloys are corroded faster by alcohols than water. This is probably because water initially gives a tight oxide protective layer after the initial attack. Alcohols do not and the corrosive attack (essentially metal + alcohol = soluble metal alkoxide) continues. To stop this, a little water is added to the alcohols which restores the oxide layer"

Any help appreciated, I'm not very knowledgeable  but very interested.

[pgk]

The issue is more complicated than that. In combustion engines that work at high temperatures, the metallic parts act as catalysts of nitrogen oxidation via radical mechanisms. The so formed traces of nitroxyl radicals may propagate the formation of traces of alkoxy radicals that terminate their life, by corrosion of the engine. 

[Talitha]

Thank you for your reply,  Is there any way to mitigate that, through additives etc?

[pgk]

Yes, there are. But their efficacy and the long term-impact in the engine life, in the environment and in the glasshouse effect are not fully clarified, yet.