The relationship between formaldehyde concentration and temperature
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Does anyone know what kind of relationship exists between formaldehyde concentration and temperature? It is generally between 10-35 degrees Celsius, as formaldehyde is a volatile solution; as the temperature increases, its concentration certainly changes. What kind of relationship exists specifically?
Formaldehyde is a substance that evaporates when the temperature is above 30 degrees and crystallizes when it is below 10 degrees. The degree of evaporation depends on the concentration of the formaldehyde solution; it is recommended to use cooling water for condensation when the temperature is above 30 degrees, and to use jacketed steam for insulation when the temperature is below 10 degrees
I think it has something to do with time; for example, at temperatures below 10 degrees, crystallization occurs after 5 hours； It may self-polymerize at 10 degrees over 20 days, but at around 50 degrees, over 95% of it can dissolve; a portion needs to undergo a reaction before it can dissolve.
Generally, it’s sufficient if the temperature is higher than the concentration; this is related to the concentration of methanol in the formaldehyde solution – a higher methanol content requires a much lower storage temperature
Reply to 1# zdh1985: Strict requirements apply regarding the temperature and concentration of formaldehyde during storage. High-concentration formaldehyde tends to polymerize into polyformaldehyde at low temperatures; therefore, for formaldehyde with a concentration of 50% or higher, the storage temperature should generally be 8°C higher than the concentration value. For formaldehyde with a concentration of 40–50%, a storage temperature 5°C higher than the concentration value is usually sufficient. As for 37% formaldehyde, the polymerization temperature is 8°C, which means that the storage temperature requirements are not very strict. At high temperatures, formaldehyde can trigger the Cornizaro reaction: 2CH2O + H2O → CH3OH + HCOOH. This reaction is accelerated at higher storage temperatures in the presence of trace amounts of iron ions.