Difference between revisions of "Desiccant"

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(Removed lanthanide salts, added several new compounds and added details to existing compounds)
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 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
Line 61: Line 60:
 
|-
 
|-
 
| 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;"|
 
−
| Often used in combination with sodium or potassium
 
−
|-
 
−
| [[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 96: Line 81:
 
|-
 
|-
 
| [[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
Line 110: Line 95:
 
|-
 
|-
 
| [[Calcium oxide]]
 
| [[Calcium oxide]]
−
| style="text-align: center;"| Basic
+
| 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
Line 129: Line 114:
 
| style="text-align: center;"|No
 
| style="text-align: center;"|No
 
| Used in desiccators, cannot be used directly
 
| Used in desiccators, cannot be used directly
−
|-
 
−
| [[Cerium(III) chloride]]
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|No
 
−
|
 
−
|-
 
−
| [[Cerium(III) nitrate]]
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|No
 
−
|
 
−
|-
 
−
| [[Cesium]]
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|No
 
−
| Expensive; reaction with water is highly explosive
 
 
|-
 
|-
 
| [[Cobalt(II) chloride]]
 
| [[Cobalt(II) chloride]]
Line 164: Line 128:
 
| style="text-align: center;"|Yes
 
| style="text-align: center;"|Yes
 
| Mostly used as water indicator
 
| Mostly used as water indicator
−
|-
 
−
| [[Dysprosium(III) chloride]]
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|No
 
−
|
 
−
|-
 
−
| [[Dysprosium(III) nitrate]]
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|No
 
−
|
 
−
|-
 
−
| [[Erbium(III) chloride]]
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|No
 
−
|
 
−
|-
 
−
| [[Erbium(III) nitrate]]
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|No
 
−
|
 
−
|-
 
−
| [[Europium(III) chloride]]
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|No
 
−
|
 
−
|-
 
−
| [[Europium(III) nitrate]]
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|No
 
−
|
 
−
|-
 
−
| [[Gadolinium(III) chloride]]
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|No
 
−
|
 
−
|-
 
−
| [[Gadolinium(III) nitrate]]
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|No
 
−
|
 
−
|-
 
−
| [[Holmium(III) chloride]]
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|No
 
−
|
 
−
|-
 
−
| [[Holmium(III) nitrate]]
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|No
 
−
|
 
−
|-
 
−
| [[Lanthanum(III) chloride]]
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|No
 
−
|
 
−
|-
 
−
| [[Lanthanum(III) nitrate]]
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|
 
−
| style="text-align: center;"|No
 
−
|
 
−
|-
 
−
| [[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;"| Neutral
 
−
| 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]]
 
| [[Magnesium]]
Line 306: Line 151:
 
|-
 
|-
 
| [[Molecular sieve|Molecular sieves]]
 
| [[Molecular sieve|Molecular sieves]]
−
| style="text-align: center;"|
+
| style="text-align: center;"| Weakly acidic
 
| style="text-align: center;"|High
 
| style="text-align: center;"|High
 
| style="text-align: center;"|High
 
| style="text-align: center;"|High
Line 312: Line 157:
 
|
 
|
 
|-
 
|-
−
| [[Neodymium(III) chloride]]
+
| [[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
−
|-
+
−
| [[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
+
−
| More often used to remove traces of water from aprotic solvents
+
 
|-
 
|-
 
| [[Potassium carbonate]]
 
| [[Potassium carbonate]]
Line 352: Line 176:
 
| style="text-align: center;"|High
 
| style="text-align: center;"|High
 
| style="text-align: center;"|Yes
 
| 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]]
 
| [[Silica gel]]
−
| style="text-align: center;"| Weak acidic
+
| 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;"| Yes
 
| style="text-align: center;"| Yes
 
|
 
|
 
|-
 
|-
 
| [[Sodium]]
 
| [[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
 
| More often used to remove traces of water from aprotic solvents
Line 411: Line 200:
 
|-
 
|-
 
| [[Sodium oxide]]
 
| [[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
 
|-
 
|-
 
| [[Sodium sulfate]]
 
| [[Sodium sulfate]]
Line 425: Line 214:
 
|-
 
|-
 
| [[Sulfur trioxide]]
 
| [[Sulfur trioxide]]
−
| style="text-align: center;"|
+
| style="text-align: center;"|Acidic
 
| style="text-align: center;"|High
 
| style="text-align: center;"|High
 
| style="text-align: center;"|Very high
 
| style="text-align: center;"|Very high
Line 435: Line 224:
 
| 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 without redistillation, which is a pain in the ass
+
| style="text-align: center;"|Yes, difficult
 
| Used in desiccators, cannot be used to dry solutions directly
 
| 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]]
 
| [[Zinc chloride]]
Line 499: Line 232:
 
| style="text-align: center;"|
 
| style="text-align: center;"|
 
| style="text-align: center;"|Yes
 
| style="text-align: center;"|Yes
−
| Drying must be done in a stream of hydrogen chloride
+
| Regenerating 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.

Revision as of 14:31, 2 November 2015

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 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 No Reaction is very slow, rarely used
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 acidic High High Yes
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 Yes Regenerating must be done in a stream of hydrogen chloride

1All compounds are considered anhydrous.

Gallery

Drying Agents Chart.png
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