vapor pressure of PEG 400

[birkATO]

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

 

[Latexman]

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,
Latexman

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

 

[georgeverghese]

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.