Difference between revisions of "Desiccant"

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(Created page with "A '''desiccant '''is a chemical which is hygroscopic enough to absorb water from hydrated compounds in the same sealed environment. ==Common desiccants== *Calcium *Calc...")
 
 
(13 intermediate revisions by 3 users not shown)
Line 7: Line 7:
 
*Concentrated [[sulfuric acid]]
 
*Concentrated [[sulfuric acid]]
 
*[[Copper(II) sulfate|Copper sulfate]] (anhydrous)
 
*[[Copper(II) sulfate|Copper sulfate]] (anhydrous)
−
*Lanthanide chlorides and nitrates
 
 
*[[Magnesium sulfate]]
 
*[[Magnesium sulfate]]
 
*[[Phosphorus pentoxide]]
 
*[[Phosphorus pentoxide]]
Line 33: Line 32:
 
|-
 
|-
 
| Activated alumina
 
| Activated alumina
−
| style="text-align: center;"|
+
| style="text-align: center;"| Basic or acidic
 
| style="text-align: center;"| Medium
 
| style="text-align: center;"| Medium
 
| style="text-align: center;"| High
 
| style="text-align: center;"| High
 
| style="text-align: center;"| Yes
 
| style="text-align: center;"| Yes
−
| Can also be used to absorb fluorides
+
| Can also be used to adsorb fluorides
 
|-
 
|-
 
| Activated charcoal
 
| Activated charcoal
Line 44: Line 43:
 
| style="text-align: center;"| Medium
 
| style="text-align: center;"| Medium
 
| style="text-align: center;"| Yes
 
| style="text-align: center;"| Yes
−
| Will also absorb other gasses
+
| Will also adsorb other gasses
 
|-
 
|-
 
| Aerogel
 
| Aerogel
Line 54: Line 53:
 
|-
 
|-
 
| [[Aluminium nitrate]]
 
| [[Aluminium nitrate]]
−
| style="text-align: center;"|
+
| style="text-align: center;"| Slightly acidic
−
| style="text-align: center;"|Medium
+
| style="text-align: center;"| Medium
−
| style="text-align: center;"|Medium
+
| style="text-align: center;"| Medium
−
| style="text-align: center;"|No
+
| style="text-align: center;"| No
 
|
 
|
 
|-
 
|-
 
| Bentonite clay
 
| Bentonite clay
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|
 
−
|
 
−
|-
 
−
| [[Benzophenone]]
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|
 
−
|
 
−
|-
 
−
| [[Cadmium nitrate]]
 
 
| style="text-align: center;"|
 
| style="text-align: center;"|
 
| style="text-align: center;"|
 
| style="text-align: center;"|
Line 82: Line 67:
 
|-
 
|-
 
| [[Calcium]]
 
| [[Calcium]]
−
| style="text-align: center;"|
+
| style="text-align: center;"| Alkaline
 
| style="text-align: center;"| High
 
| style="text-align: center;"| High
 
| style="text-align: center;"| Very high
 
| style="text-align: center;"| Very high
Line 95: Line 80:
 
| Deliquescent; often used in drying tubes
 
| Deliquescent; often used in drying tubes
 
|-
 
|-
−
|[[Calcium hydride]]
+
| [[Calcium hydride]]
−
| style="text-align: center;"|
+
| style="text-align: center;"| Alkaline
−
| style="text-align: center;"|High
+
| style="text-align: center;"| High
−
| style="text-align: center;"|Very high
+
| style="text-align: center;"| Very high
−
| style="text-align: center;"|No
+
| style="text-align: center;"| No
 
|
 
|
 
|-
 
|-
−
|[[Calcium nitrate]]
+
| [[Calcium nitrate]]
−
| style="text-align: center;"|Neutral
+
| style="text-align: center;"| Neutral
−
| style="text-align: center;"|Medium
+
| style="text-align: center;"| Medium
−
| style="text-align: center;"|Medium
+
| style="text-align: center;"| Medium
−
| style="text-align: center;"|Yes
+
| style="text-align: center;"| Yes
 
|
 
|
 
|-
 
|-
−
|[[Calcium oxide]]
+
| [[Calcium oxide]]
−
| style="text-align: center;"|
+
| style="text-align: center;"| Alkaline
−
| style="text-align: center;"|High
+
| style="text-align: center;"| High
−
| style="text-align: center;"|High
+
| style="text-align: center;"| High
−
| style="text-align: center;"|No
+
| style="text-align: center;"| No
−
|
+
| style="text-align: center;"| Calcium oxide will only remove water from ethanol until 5000 ppm.<ref>Ford, S. G.; Marvel, C. S., Organic Syntheses; Wiley: New York, 1943; Collect. Vol. 11, p 373.</ref>
 
|-
 
|-
−
|[[Calcium sulfate]]
+
| [[Calcium sulfate]]
−
| style="text-align: center;"|Neutral
+
| style="text-align: center;"| Neutral
−
| style="text-align: center;"|Low
+
| style="text-align: center;"| Low
−
| style="text-align: center;"|High
+
| style="text-align: center;"| High
−
| style="text-align: center;"|Yes
+
| style="text-align: center;"| Yes
−
|Very fast and efficient drying agent, but a lot of drying agent might be necessary
+
| Very fast and efficient drying agent, but a lot of drying agent might be necessary
 
|-
 
|-
−
|Cement (Portland)
+
| [[Portland cement|Cement (Portland)]]
−
| style="text-align: center;"|Alkaline
+
| style="text-align: center;"| Alkaline
−
| style="text-align: center;"|Medium
+
| style="text-align: center;"| Medium
−
| style="text-align: center;"|Medium
+
| style="text-align: center;"| Medium
−
| style="text-align: center;"|No
+
| style="text-align: center;"| No
−
|Used in dessicators, cannot be used directly
+
| Used in desiccators, cannot be used directly
 
|-
 
|-
−
|[[Cerium(III) chloride]]
+
| [[Cobalt(II) chloride]]
 
| style="text-align: center;"|
 
| style="text-align: center;"|
 
| style="text-align: center;"|
 
| style="text-align: center;"|
 
| style="text-align: center;"|
 
| style="text-align: center;"|
−
| style="text-align: center;"|No
+
| style="text-align: center;"| Yes
−
|
+
| Mostly used as water indicator
 
|-
 
|-
−
|[[Cerium(III) nitrate]]
+
| [[Copper(II) sulfate]]
−
| style="text-align: center;"|
+
| style="text-align: center;"| Neutral
−
| style="text-align: center;"|
+
| style="text-align: center;"| Low
−
| style="text-align: center;"|
+
| style="text-align: center;"| Medium
−
| style="text-align: center;"|No
+
| style="text-align: center;"| Yes
−
|
+
| Mostly used as water indicator
 
|-
 
|-
−
|[[Cesium]]
+
| [[Magnesium]]
 
| style="text-align: center;"|
 
| style="text-align: center;"|
 
| style="text-align: center;"|
 
| style="text-align: center;"|
−
| style="text-align: center;"|
+
| style="text-align: center;"| High
−
| style="text-align: center;"|No
+
| style="text-align: center;"| No
−
|Expensive; reaction with water is highly explosive
+
| Reaction is very slow, rarely used; Mostly used for removing traces of water
 
|-
 
|-
−
|[[Cobalt(II) chloride]]
+
| [[Magnesium sulfate]]
−
| style="text-align: center;"|
+
| style="text-align: center;"| Neutral
−
| style="text-align: center;"|
+
| style="text-align: center;"| High
−
| style="text-align: center;"|
+
| style="text-align: center;"| Medium
−
| style="text-align: center;"|Yes
+
| style="text-align: center;"| Yes
−
|Mostly used as water indicator
+
| Good multipurpose drying agent; exists in powder and granular form; has the ability to absorb a lot of water
 
|-
 
|-
−
|[[Copper(II) sulfate]]
+
| [[Magnesium chloride]]
−
| style="text-align: center;"|Neutral
+
| style="text-align: center;"| Neutral
−
| style="text-align: center;"|Low
+
| style="text-align: center;"| High
−
| style="text-align: center;"|Medium
+
| style="text-align: center;"| Medium
−
| style="text-align: center;"|Yes
+
| style="text-align: center;"| Yes
−
|Mostly used as water indicator
+
| Deliquescent
 
|-
 
|-
−
|[[Dysprosium(III) chloride]]
+
| [[Molecular sieve|Molecular sieves]]
−
| style="text-align: center;"|
+
| style="text-align: center;"| Weakly basic
−
| style="text-align: center;"|
+
| style="text-align: center;"| High
−
| style="text-align: center;"|
+
| style="text-align: center;"| High
−
| style="text-align: center;"|No
+
| style="text-align: center;"| Yes
−
|
+
| Drying takes hours to days; Unsuitable for drying ketones
 
|-
 
|-
−
|[[Dysprosium(III) nitrate]]
+
| [[Potassium carbonate]]
−
| style="text-align: center;"|
+
| style="text-align: center;"| Acidic
−
| style="text-align: center;"|
+
| style="text-align: center;"| Medium
−
| style="text-align: center;"|
+
| style="text-align: center;"| High
−
| style="text-align: center;"|No
+
| style="text-align: center;"| No
−
|
+
| Good for thoroughly drying predried compounds
 
|-
 
|-
−
|[[Erbium(III) chloride]]
+
| [[Potassium carbonate]]
−
| style="text-align: center;"|
+
| style="text-align: center;"| Alkaline
−
| style="text-align: center;"|
+
| style="text-align: center;"| Low
−
| style="text-align: center;"|
+
| style="text-align: center;"| Medium
−
| style="text-align: center;"|No
+
| style="text-align: center;"| Yes
−
|
+
| Only for alkaline compounds
 
|-
 
|-
−
|[[Erbium(III) nitrate]]
+
| [[Potassium hydroxide]]
−
| style="text-align: center;"|
+
| style="text-align: center;"| Alkaline
−
| style="text-align: center;"|
+
| style="text-align: center;"| High
−
| style="text-align: center;"|
+
| style="text-align: center;"| High
−
| style="text-align: center;"|No
+
| style="text-align: center;"| Yes
 
|
 
|
 
|-
 
|-
−
|[[Europium(III) chloride]]
+
| [[Silica gel]]
−
| style="text-align: center;"|
+
| style="text-align: center;"| Weakly acidic
−
| style="text-align: center;"|
+
| style="text-align: center;"| High
−
| style="text-align: center;"|
+
| style="text-align: center;"| Medium
−
| style="text-align: center;"|No
+
| style="text-align: center;"| Yes
 
|
 
|
 
|-
 
|-
−
|[[Europium(III) nitrate]]
+
| [[Sodium]]
−
| style="text-align: center;"|
+
| style="text-align: center;"| Alkaline
−
| style="text-align: center;"|
+
| style="text-align: center;"| High
−
| style="text-align: center;"|
+
| style="text-align: center;"| Very High
−
| style="text-align: center;"|No
+
| style="text-align: center;"| No
−
|
+
| More often used to remove traces of water from aprotic solvents
 
|-
 
|-
−
|[[Gadolinium(III) chloride]]
+
| [[Sodium hydroxide]]
−
| style="text-align: center;"|
+
| style="text-align: center;"| Alkaline
−
| style="text-align: center;"|
+
| style="text-align: center;"| High
−
| style="text-align: center;"|
+
| style="text-align: center;"| High
−
| style="text-align: center;"|No
+
| style="text-align: center;"| Yes
−
|
+
| Very effective for basic compounds, such as amines; caustic
 
|-
 
|-
−
|[[Gadolinium(III) nitrate]]
+
| [[Sodium oxide]]
−
| style="text-align: center;"|
+
| style="text-align: center;"| Alkaline
−
| style="text-align: center;"|
+
| style="text-align: center;"| High
−
| style="text-align: center;"|
+
| style="text-align: center;"| Very High
−
| style="text-align: center;"|No
+
| style="text-align: center;"| No
−
|
+
| More effective when used to dry compounds predried with another desiccant
 
|-
 
|-
−
|[[Holmium(III) chloride]]
+
| [[Sodium sulfate]]
−
| style="text-align: center;"|
+
| style="text-align: center;"| Neutral
−
| style="text-align: center;"|
+
| style="text-align: center;"| High
−
| style="text-align: center;"|
+
| style="text-align: center;"| Low
−
| style="text-align: center;"|No
+
| style="text-align: center;"| Yes
−
|
+
| Used to dry solvents; Requires lots of it; only good for predrying;
 
|-
 
|-
−
|[[Holmium(III) nitrate]]
+
| [[Sulfur trioxide]]
−
| style="text-align: center;"|
+
| style="text-align: center;"| Acidic
−
| style="text-align: center;"|
+
| style="text-align: center;"| High
−
| style="text-align: center;"|
+
| style="text-align: center;"| Very high
−
| style="text-align: center;"|No
+
| style="text-align: center;"| No
−
|
+
| Tends to form a mist of sulfuric acid in contact with moist air
 
|-
 
|-
−
|[[Lanthanum(III) chloride]]
+
| [[Sulfuric acid]] (concentrated)
−
| style="text-align: center;"|
+
| style="text-align: center;"| Acidic
−
| style="text-align: center;"|
+
| style="text-align: center;"| High
−
| style="text-align: center;"|
+
| style="text-align: center;"| High
−
| style="text-align: center;"|No
+
| style="text-align: center;"| Yes, difficult
−
|
+
| Used in desiccators, cannot  be used to dry solutions directly
 
|-
 
|-
−
|[[Lanthanum(III) nitrate]]
+
| [[Zinc chloride]]
−
| style="text-align: center;"|
+
| style="text-align: center;"| Acidic
−
| style="text-align: center;"|
+
| style="text-align: center;"| Low
−
| style="text-align: center;"|
+
| style="text-align: center;"| Low
−
| style="text-align: center;"|No
+
| style="text-align: center;"| Yes
−
|
+
| Regenerating must be done in a stream of hydrogen chloride
−
|-
+
−
|[[Lithium]]
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|High
+
−
| style="text-align: center;"|High
+
−
| style="text-align: center;"|No
+
−
|Expensive; reaction with water releases hydrogen; least violent reaction of all alkaline metals
+
−
|-
+
−
|[[Lithium bromide]]
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|High
+
−
| style="text-align: center;"|High
+
−
| style="text-align: center;"|Yes
+
−
|
+
−
|-
+
−
|[[Lithium chloride]]
+
−
| style="text-align: center;"|Neutral
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|Yes
+
−
|Drying must be done in a stream of hydrogen chloride
+
−
|-
+
−
|[[Luthetium(III) chloride]]
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|No
+
−
|
+
−
|-
+
−
|[[Luthetium(III) nitrate]]
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|No
+
−
|
+
−
|-
+
−
|[[Magnesium]]
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|No
+
−
|Reaction is very slow, rarely used
+
−
|-
+
−
|[[Magnesium sulfate]]
+
−
| style="text-align: center;"|Neutral
+
−
| style="text-align: center;"|High
+
−
| style="text-align: center;"|Medium
+
−
| style="text-align: center;"|Yes
+
−
|Good multipurpose drying agent; exists in powder and granular form; has the ability to absorb a lot of water
+
−
|-
+
−
|[[Magnesium chloride]]
+
−
| style="text-align: center;"|Neutral
+
−
| style="text-align: center;"|High
+
−
| style="text-align: center;"|Medium
+
−
| style="text-align: center;"|Yes
+
−
|Deliquescent
+
−
|-
+
−
|Molecular sieves
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|High
+
−
| style="text-align: center;"|High
+
−
| style="text-align: center;"|Yes
+
−
|
+
−
|-
+
−
|[[Neodymium(III) chloride]]
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|No
+
−
|
+
−
|-
+
−
|[[Neodymium(III) nitrate]]
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|No
+
−
|
+
−
|-
+
−
|[[Phosphorus pentoxide]]
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|No
+
−
|
+
−
|-
+
−
|[[Potassium]]
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|No
+
−
|
+
−
|-
+
−
|[[Potassium carbonate]]
+
−
| style="text-align: center;"|Alkaline
+
−
| style="text-align: center;"|Low
+
−
| style="text-align: center;"|Medium
+
−
| style="text-align: center;"|Yes
+
−
|Only for alkaline compounds
+
−
|-
+
−
|[[Potassium hydroxide]]
+
−
| style="text-align: center;"|Alkaline
+
−
| style="text-align: center;"|High
+
−
| style="text-align: center;"|High
+
−
| style="text-align: center;"|Yes
+
−
|Very effective for basic compounds, such as amines; caustic
+
−
|-
+
−
|[[Praseodymium(III) chloride]]
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|No
+
−
|
+
−
|-
+
−
|[[Praseodymium(III) nitrate]]
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|No
+
−
|
+
−
|-
+
−
|[[Rubidium]]
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|No
+
−
|Expensive; reaction with water is highly explosive
+
−
|-
+
−
|[[Samarium(III) chloride]]
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|No
+
−
|
+
−
|-
+
−
|[[Samarium(III) nitrate]]
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|No
+
−
|
+
−
|-
+
−
|Silica gel
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|Yes
+
−
|
+
−
|-
+
−
|[[Sodium]]
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|No
+
−
|
+
−
|-
+
−
|[[Sodium hydroxide]]
+
−
| style="text-align: center;"|Alkaline
+
−
| style="text-align: center;"|High
+
−
| style="text-align: center;"|High
+
−
| style="text-align: center;"|Yes
+
−
|Very effective for basic compounds, such as amines; caustic
+
−
|-
+
−
|[[Sodium oxide]]
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|No
+
−
|
+
−
|-
+
−
|[[Sodium sulfate]]
+
−
| style="text-align: center;"|Neutral
+
−
| style="text-align: center;"|High
+
−
| style="text-align: center;"|Low
+
−
| style="text-align: center;"|Yes
+
−
|Used to dry solvents; Requires lots of it; only good for predrying;
+
−
|-
+
−
|[[Sulfur trioxide]]
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|High
+
−
| style="text-align: center;"|Very high
+
−
| style="text-align: center;"|No
+
−
|Tends to form a mist of sulfuric acid in contact with moist air
+
−
|-
+
−
|[[Sulfuric acid]] concentrated
+
−
| style="text-align: center;"|Acidic
+
−
| style="text-align: center;"|High
+
−
| style="text-align: center;"|High
+
−
| style="text-align: center;"|No
+
−
|Used in desiccators, cannot be used to dry solutions directly
+
−
|-
+
−
|[[Terbium(III) chloride]]
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|No
+
−
|
+
−
|-
+
−
|[[Terbium(III) nitrate]]
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|No
+
−
|
+
−
|-
+
−
|[[Thulium(III) chloride]]
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|No
+
−
|
+
−
|-
+
−
|[[Thulium(III) nitrate]]
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|No
+
−
|
+
−
|-
+
−
|[[Ytterbium(III) chloride]]
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|No
+
−
|
+
−
|-
+
−
|[[Ytterbium(III) nitrate]]
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|No
+
−
|
+
−
|-
+
−
|[[Yttrium(III) chloride]]
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|No
+
−
|
+
−
|-
+
−
|[[Yttrium(III) nitrate]]
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|No
+
−
|
+
−
|-
+
−
|[[Zinc chloride]]
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|
+
−
| style="text-align: center;"|Yes
+
−
|Drying must be done in a stream of hydrogen chloride
+
 
|}
 
|}
 
<sup>1</sup>All compounds are considered anhydrous.
 
<sup>1</sup>All compounds are considered anhydrous.
  
 
==Gallery==
 
==Gallery==
−
[[File:Drying_Agents2.jpg|thumb|left|400px]]
+
[[File:Drying_Agents_Chart.png|thumb|left|400px]]
 +
 
 
[[Category:Chemical compounds]]
 
[[Category:Chemical compounds]]
−
[[Category:Dessicants]]
+
[[Category:Desiccants]]
 +
[[Category:Data tables]]
 +
[[Category:Irritants]]

Latest revision as of 21:08, 3 July 2017

A desiccant is a chemical which is hygroscopic enough to absorb water from hydrated compounds in the same sealed environment.

Common desiccants

Comparison

Substance1 pH Water capacity Effectiveness Reversible Notes
Acetonitrile High High Yes Rarely used
Activated alumina Basic or acidic Medium High Yes Can also be used to adsorb fluorides
Activated charcoal Medium Medium Yes Will also adsorb other gasses
Aerogel High High Yes Expensive
Aluminium nitrate Slightly acidic Medium Medium No
Bentonite clay
Calcium Alkaline High Very high No Reaction with water releases large amounts of hydrogen
Calcium chloride Neutral High Medium Yes Deliquescent; often used in drying tubes
Calcium hydride Alkaline High Very high No
Calcium nitrate Neutral Medium Medium Yes
Calcium oxide Alkaline High High No Calcium oxide will only remove water from ethanol until 5000 ppm.[1]
Calcium sulfate Neutral Low High Yes Very fast and efficient drying agent, but a lot of drying agent might be necessary
Cement (Portland) Alkaline Medium Medium No Used in desiccators, cannot be used directly
Cobalt(II) chloride Yes Mostly used as water indicator
Copper(II) sulfate Neutral Low Medium Yes Mostly used as water indicator
Magnesium High No Reaction is very slow, rarely used; Mostly used for removing traces of water
Magnesium sulfate Neutral High Medium Yes Good multipurpose drying agent; exists in powder and granular form; has the ability to absorb a lot of water
Magnesium chloride Neutral High Medium Yes Deliquescent
Molecular sieves Weakly basic High High Yes Drying takes hours to days; Unsuitable for drying ketones
Potassium carbonate Acidic Medium High No Good for thoroughly drying predried compounds
Potassium carbonate Alkaline Low Medium Yes Only for alkaline compounds
Potassium hydroxide Alkaline High High Yes
Silica gel Weakly acidic High Medium Yes
Sodium Alkaline High Very High No More often used to remove traces of water from aprotic solvents
Sodium hydroxide Alkaline High High Yes Very effective for basic compounds, such as amines; caustic
Sodium oxide Alkaline High Very High No More effective when used to dry compounds predried with another desiccant
Sodium sulfate Neutral High Low Yes Used to dry solvents; Requires lots of it; only good for predrying;
Sulfur trioxide Acidic High Very high No Tends to form a mist of sulfuric acid in contact with moist air
Sulfuric acid (concentrated) Acidic High High Yes, difficult Used in desiccators, cannot be used to dry solutions directly
Zinc chloride Acidic Low Low Yes Regenerating must be done in a stream of hydrogen chloride

1All compounds are considered anhydrous.

Gallery

Drying Agents Chart.png
  1. ↑ Ford, S. G.; Marvel, C. S., Organic Syntheses; Wiley: New York, 1943; Collect. Vol. 11, p 373.
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