3 replies to this topic

[sateeshkumar830]

Hiiiiiii

        What is the relationship between freezing point vs vacuum pressure. I have done MDC distillitaion under vacuum. -20c utility was used for condenser. Mdc(Methylene dichloride) Freezing point is -40c. But condenser got freeze. i know the relationship between boiling point vs vapor pressure.  We will calculate this by using antonie equation. But what is the relationship between freezing point vs vacuum pressure. on what parameters it does depends. We have to use same formula or what. 

Hope expecting replies from you.

                                                       Thanking you.

[PaoloPemi]

for estimating freezing point of a mixture you can solve phase equilibria,

a simple solution would be to use the relation for solid's vapor pressure,

I attach as example the temperature dependent parameters

in Prode Properties data bank for methylchloride,

possibly you have other components since my values (for pure methyl chloride and dichloride) are lower

than yours (about 178 K as freezing point for pure dichloromethane or methyl dichloride)

for mixtures a better approach would be a method such as

Prode Simplified Solid Solution Model (SSM) for multiphase equilibria,

SSM calculates fugacity of solid phase from fugacity of liquid phase,

this allows to solve both vapor-solid and liquid-solid equilibria

as well as multiphase

Attached Files

•  solidvaporpressure1.jpg   71.85KB   2 downloads

Edited by PaoloPemi, 03 April 2014 - 11:22 AM.

[sateeshkumar830]

Waiting For More Replies.. Please anybody Respond to my question.

[marchem]

which answer do you wish to receive ?

 

Have you read Paolo's post with the notes about methyl dichloride freezing point ?

 

You may give us more detailed information.