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Effect of low pressure on solids

  1. Jul 19, 2016 #1
    I have a question about low pressure. So if i want to evaporate water from a pulverized product, but keep a solid substance intact (unknow solid, unknown properties, higher boiling point than water, but only slightly), should i do it with low (not too low) pressure? Will it remove more of the substance compared to air drying?
     
  2. jcsd
  3. Jul 19, 2016 #2
    You've created a bit of a problem. Your unknown substance is a solid with a boiling point only slightly higher than water.
    Everything I can think of that is solid when water is liquid has a boiling point that is well above the boiling point of water.

    Perhaps iodine comes closest to what you are describing. It has a melting point of 113.7C and a boiling point of 180.3C. I would call that more than "slightly higher".

    It's really impossible to say without dealing in specifics. If the "solid" has a low latent heat of vaporization and a low vapor pressure at 100C, then you better keep it cold.

    We also don't know what affinity the "solid" has for water.
     
  4. Jul 20, 2016 #3
    By slightly, i ment relatively slightly. The thing is i can not lose more of the substance as i only have a limited source of the plant as its season has passed.
     
  5. Jul 20, 2016 #4
    Is this an organic material?
     
  6. Jul 20, 2016 #5

    berkeman

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    Staff: Mentor

    Well which is it? Is the substance unknown, or do you know what it is because you know what plant you ground up?
     
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