Vacuum Sublimation
Vacuum Sublimation - Related Videos
05:39
Purification of Ferrocene by Sublimation
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2023
Source: Tamara M. Powers, Department of Chemistry, Texas A&M University Sublimation, the direct phase transition of a solid into a gas without first becoming a liquid, takes place at temperatures and pressures lower than that of the compound's triple point (Figure 1).The process of sublimation can be utilized to purify both organic and inorganic solids. During the purification technique, a solid is heated directly into the gas-phase. All non-volatile impurities are left behind while the...
02:33
Phase Transitions: Sublimation and Deposition
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2020
Some solids can transition directly into the gaseous state, bypassing the liquid state, via a process known as sublimation. At room temperature and standard pressure, a piece of dry ice (solid CO2) sublimes, appearing to gradually disappear without ever forming any liquid. Snow and ice sublimate at temperatures below the melting point of water, a slow process that may be accelerated by winds and the reduced atmospheric pressures at high altitudes. When solid iodine is warmed, the solid sublimes...
01:03
Sublimation
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2024
Sublimation is the direct transformation of a solid to a gaseous state. For instance, at standard pressure and room temperature, solid carbon dioxide sublimes to gaseous carbon dioxide. The phase diagram depicts the conditions required for sublimation. This process occurs at the solid-gas phase boundary and is not observed above the triple point of the substance. The reverse of sublimation is called deposition, where a gaseous substance condenses directly into a solid. Sublimation and...
08:36
Sublimation of DAN Matrix for the Detection and Visualization of Gangliosides in Rat Brain Tissue for MALDI Imaging Mass Spectrometry
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Cited by 43 •
2017
A protocol for the sublimation of DAN matrix onto rat brain tissue for the detection of gangliosides using MALDI Imaging Mass Spectrometry is presented.
06:20
Proper Operation of Vacuum Based Equipment
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2023
Source: Robert M. Rioux, Ajay Sathe & Zhifeng Chen, Pennsylvania State University, University Park, PA Vacuum is required for a number of laboratory procedures. This is most routinely achieved in the laboratory by the use of vacuum pumps. In addition to working at low pressures, vacuum pumps can also be used to enable rapid changing of the atmospheres in a reactor or flask by evacuation and backfilling.
FAQs
Reduced pressure allows the target solid to vaporize at a lower temperature, which can keep it below its melting point while heating. A compound that sublimes readily can therefore be transferred into the vapor phase without requiring conditions that strongly promote thermal decomposition. Nonvolatile impurities remain behind, supporting separation.
The temperature gradient determines where the vapor is collected. Heating drives material away from the source, while a cooler surface encourages the vapor to deposit as a solid. Maintaining a deliberate difference between the heated region and collection region helps direct transport and makes the recovered material easier to isolate.
Compared with a treatment that takes a solid through its melting point, this approach can keep the material solid during heating and transfer. That distinction matters for compounds that sublime readily, because avoiding the molten state may reduce opportunities for thermal decomposition and preserve a recoverable purified solid.
Pressure and temperature must be controlled together rather than independently. Pressure influences the temperature needed for vaporization, while heating rate and the temperature of the receiving surface affect whether material moves and deposits effectively. Consistent control of these conditions, especially the pressure and temperature gradient, is central to reproducible purification results.
A basic workflow begins by placing the solid in a system where pressure can be reduced, then applying controlled heat to the material. The vapor is directed toward a cooler surface, where it deposits and can be collected as a solid. Separating the collected deposit from material left at the source completes the purification workflow.
The collected solid and the residue at the original source provide different purification outcomes. A readily subliming compound can appear in the cooled deposit, whereas nonvolatile impurities tend to remain with the starting material. Comparing these locations helps assess whether the process has separated the desired compound from contaminants and whether collection was effective.
Beyond routine purification, the method also supports freeze-drying and preparation of purified solid materials. In each case, the useful outcome depends on moving material under reduced pressure and controlling where it re-forms. Within chemistry, this makes it relevant both to isolation of suitable subliming compounds and to processes that require a clean, recoverable solid product.