A word about using methanol around aluminum. Here at work we have high pressure liquid chormatography systems that use methanol as an eluent. We were having problems with the system and it turned out that the methanol was eating away at the aluminum pump heads. Filling a beaker with methanol and submersing the head gave a rather interesting result. The head fizzed as if in hydrochloric acid turning the liquid gray with dissoved metal. This was at room temp. It could be even more corrosive at high temp and pressure.
Use of methanol
- Thread starter Mr GCMS
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When I did my engineering thesis, it had to do with fuel flow in inlet manifolds.
The previous bod has taken a sideways step and messed around with mathanol, in a system that was predominently aluminium.
The injectors (bosch mechanical from an Ovlov or somesuch) were clagged with that white deposit, that was ridiculously hard to shift.
ended up putting a bottle of "System 1" fuel injection cleaner in a litre of petrol (about 50 times the recommended dosage). It went from a drip drip action to a proper spray pattern in about half of the litre of fuel.
The previous bod has taken a sideways step and messed around with mathanol, in a system that was predominently aluminium.
The injectors (bosch mechanical from an Ovlov or somesuch) were clagged with that white deposit, that was ridiculously hard to shift.
ended up putting a bottle of "System 1" fuel injection cleaner in a litre of petrol (about 50 times the recommended dosage). It went from a drip drip action to a proper spray pattern in about half of the litre of fuel.
I don't know how to explain what you saw. I'm a chemist and I've never seen methanol react with aluminum like that. I suspect there was something else mixed with the methanol which you didn't know about. Or, maybe your pump wasn't designed for use with methanol.
Here is a portion of an MSDS I found on the web. It is typical of all others I've ever seen concerning the handling of methanol:
Materials to avoid:
METALS
(e.g. powdered aluminum or magnesium) - mixtures can detonate, with more power than military eplosives.
Corrosivity to Metals:
Methanol is not corrosive to most metals. Admiralty brass, high silicon iron, naval bronze, nickel-resist and silicon copper have excellent corrosion resistance (less than 2 mils (50.8 um) penetration/year), while carbon steel, types 304/347, 316 and 400 stainless steels, copper, brass, bronze, ***aluminum***, nickel, lead, tantalum, titanium and zirconium have good resistance (less than 20 mils (505 um)/year).
In addition, how do you explain all the RC airplane enthusiasts who use methanol as their fuel in their aluminum engines without problems?
[ December 18, 2002, 10:46 AM: Message edited by: Sciguyjim ]
Here is a portion of an MSDS I found on the web. It is typical of all others I've ever seen concerning the handling of methanol:
Materials to avoid:
METALS
(e.g. powdered aluminum or magnesium) - mixtures can detonate, with more power than military eplosives.
Corrosivity to Metals:
Methanol is not corrosive to most metals. Admiralty brass, high silicon iron, naval bronze, nickel-resist and silicon copper have excellent corrosion resistance (less than 2 mils (50.8 um) penetration/year), while carbon steel, types 304/347, 316 and 400 stainless steels, copper, brass, bronze, ***aluminum***, nickel, lead, tantalum, titanium and zirconium have good resistance (less than 20 mils (505 um)/year).
In addition, how do you explain all the RC airplane enthusiasts who use methanol as their fuel in their aluminum engines without problems?
[ December 18, 2002, 10:46 AM: Message edited by: Sciguyjim ]
MolaKule
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Alcohols can either be acidic or base. What makes them basic is the addition of the oxygen's unshared electron pairs. In the case of methanol, it can be very acidic.
The methanol you used was likely a very strong methanol of great concentration.
When reacted with a metal, a lot of hydrogen gas is liberated, hence the "fizzing.".
In fuels, the methanol is in low concentration and less reactive with metals.
The methanol you used was likely a very strong methanol of great concentration.
When reacted with a metal, a lot of hydrogen gas is liberated, hence the "fizzing.".
In fuels, the methanol is in low concentration and less reactive with metals.
I'm not too sure... Methanol has a pKa of 15.5...I wouldn't consider this very acidic. That being said, acid/base chemistry is sometimes a relative matter: For example, you said alchohols can either be acids or bases. Well, water can also be either an acid or a base...it just depends whether it's abstracting (taking) or contributing a proton (the same as R-OH's).
Speaking of which...water has a pKa of 15.7.
Speaking of which...water has a pKa of 15.7.
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