- 2

- 0

I am a PhD student in chemistry, and need to determine the pressure of a reaction to be carried out

I have a steel pressure vessel with an inner Teflon container (total volume = 270 mL) which is placed in an oven at 250°C. I wish to put 240 mL of water into this container (along with 1 g of material). At this temperature, I know that the head-space pressure to be approximately 40 bar. However, the relative specific volume of water at 250°C (to that at RT) is 1.25. I believe this means that my water wants to take up a volume of 300 mL. As this is 30 mL larger than the container itself, I am not sure if it will therefore be exerting an extra pressure much larger than the head-space pressure.

I've tried a few different ways to calculate a value for this second pressure, but to no avail. One was to use water's compressibility and bulk modulus, but keep ending up with a value upwards of 2500 bar, which is just ridiculous.

Any help would be appreciated in helping me solve my problem. Please ask if I have left out any information required of the system.

Thanks,