Freezing Temp of Glycerin?
Freezing Temp of Glycerin?
(OP)
Can someone help me? I need to know the temperature at which glycerin and ammonia freezes, and I can't seem to find this info in my books.
Thanks,
Roach
Thanks,
Roach
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Freezing Temp of Glycerin?
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RE: Freezing Temp of Glycerin?
RE: Freezing Temp of Glycerin?
F.P. of glycerine = 17.0 degrees F
ammonia (aqua) - some other properties listed, but not freezing point
Partial answer anyway..
Carl
RE: Freezing Temp of Glycerin?
Thanks,
Roach
RE: Freezing Temp of Glycerin?
RE: Freezing Temp of Glycerin?
What does the substance do at 17.9ºC that it doesn't do at any other temp????
Thanks for the info Trihydrate. I thought this was correct, but it made no sense to me. Guess it is best that I stick with mechanics.
Thanks,
Joey
RE: Freezing Temp of Glycerin?
Maybe the containers, the guage and the viscometers from the reports, were super clean and the glycerol was supercooled.
I was looking into using a glycerol-water mixture as a substitute for mineral oil in a hydraulic system.
The temperature of the fluid will be controlled, so the viscosity of the fluid will not be a problem.
I have searched through all of the literature available to me and have found little mention of it being used as a hydraulic fluid.
Is there any reason why it isn't commonly used as a hydraulic fluid?
RE: Freezing Temp of Glycerin?
It was of some concern that unlagged lines would freeze in winter and it would be a problem to melt the lines again. In test the lab was unable to get the glycerine to freeze although it does become very viscose. We believe small impurities were changing the melting and freezing point significantly.
scheffler - One reason for not using water/glycerine solutions could be, microbial action becomes fairly rapid below a 70% glycerine concentration. Above this it is too conc for bacteria to thrive.
RE: Freezing Temp of Glycerin?
I remember hearing in college that glycerine could be supercooled in clean containers and so stay liquid at far lower temps than expected. Once it freezes though it cannot be supercooled again because of microscopic collections of molecules here and there retaining the crystalline pattern and acting as nucleation points in the future. This caused some headaches in early attempts to pump it through pipelines in cold climates.
RE: Freezing Temp of Glycerin?
Glycerol, as water, has a strong intermolecular (and intramolecular H-bond effect that makes its BP as high as 290C. I wonder whether this could be the explanation for the disparity between its MP and a lower FP.
I can bring an example of paraffin waxes which are mixtures of hydrocarbons. The so-called mycrocrystalline waxes show "congealing" points that are invariably lower than the drop "melting" points.
Undercooling of pure liquids below their freezing points is possible: carefully undercooled water has been studied at -30C !
Amorphous solids such as glass and polymers -they don't form well defined crystals- can be cooled (supercooled) way below their freezing points until they solidify because of the lack of sufficient order in their molecular structure and arrangements to allow for short-distance intermolecular attraction effects to take place.
Somebody rightly said: the more I learn the more confused I am.