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Chemistry / Re: Methyl Formate used as refrigerant in antique refrigerators.
« on: 01/11/2013 20:44:11 »Would high pressure, or cycling between high and low pressures also affect the decomposition.
The reaction with water consumes the water, so it would be dependent on the amount of water in the system. The decomposition to carbon monoxide and methanol would not be quantity dependent. However, is it possible that carbon monoxide reaction could be catalyzed by something else in the system such as formic acid?
All of this is way above my head.
However, here are two patents GE took out in regards to methyl formate breaking down. The first talks about adding alcohol to the system, the next seems to replace that with adding lard to the lubricating oil to prevent or reduce the amount the methyl formate breaks down.
https://www.google.com/patents/US1854984?dq=methyl+formate&hl=en&sa=X&ei=ARJ0UsDIFYahsATe8IGIBA&ved=0CF8Q6AEwBw
https://www.google.com/patents/US1920845?dq=methyl+formate&hl=en&sa=X&ei=ARJ0UsDIFYahsATe8IGIBA&ved=0CG4Q6AEwCg
Another bizarre problem we have found is the methyl formate or something in the system appears to eat away the valve seat in the float valve. The float valve is the metering device in the system. The same design float valve is used on sulphur dioxide machines and does not suffer any such damage or erosion. We have been replacing the float valve with a simple capillary tube with great results.