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vapor pressure of PEG 400

vapor pressure of PEG 400

vapor pressure of PEG 400

Hi, I am trying to find out if there is such a thing as a published vapor pressure for polyethylene glycol 400 at a elevated temperature. SDS's I have found show the vapor pressure is < 0.01 mm Hg psi at 20C. My application is using PEG400 at about 300 F. The problem is that a state regulator is trying to say that there are VOC's being emitted from the PEG400 solution and since they can't find a vapor pressure for PEG400 at elevated temperature, they are assuming ethylene glycol, which is not even close to the same thing as PEG400. I would expect PEG400 to have a much lower vapor pressure than ethylene glycol at 300F. Does anyone know of a resource that either indicates how to estimate a vapor pressure at elevated temperature for PEG400 or supporting documentation that it is very very low, like less than 0.1 psi or something?

-Ryan Birkenholz, Licensed PE in MN and IA

RE: vapor pressure of PEG 400

PEG-400 is MW = 400 (about 8.7 oxyethylene units per molecule). You would be much better off modeling it with the highest MW glycol homolog you can find data on, like di-, tri-, or tetra-ethylene glycol. I know Aspen 7.3 has properties on those. If nobody comes thru with data on PEG-400, and you need data on tetra-EG, let me know.

Good luck,

To a ChE, the glass is always full - 1/2 air and 1/2 water.

RE: vapor pressure of PEG 400

Maybe this doesnt help, but the sat vap pressure of tetraethylene glycol (mol wt 194) is 1.0mmHg at 154degC (from Perry Chem Engg Handbook, 6th edition, pg 3-61), which translates to 0.0193psia at 310degF, so one would expect the sat vap pressure for polyethylene glycol with a mean mol wt of 400 to be even lower at 300degF.

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