Hi jame2409!
I expected EDTA to decompose before reaching 600°C... Is it that stable? From Sigma-Aldrich's safety datasheet, I read:
"Melting range: 250°C - decomposes" and "boiling point: no data"
which I interpret as decomposition beginning around 250°C, a more expected value for an organic compound.
Could it be that you read for the boiling point a
"predicted value: 600°C"?
Don't believe computed values, never ever.
Other people here must know it better than I.