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Solvent Drying and Drying Agents

Related link :

Drying with sodium wire :

Disposal of spent sodium, magnesium and calcium hydride

On this page : Properties of solvents

and methods used for drying them with specific drying agents

Removing water from Solvents

There are various ways of removing water and other impurities from a solution. This can become

a major task once the used reagents are also sensitive towards water e.g. Grignard reagents or

enolates. If water is one of the products, it also has a detrimental effect on the yield and/or

reaction rate. In those cases, drying agents like activated alumina¹, calcium hydride (CaH2),

sodium metal (in combination with benzophenone which forms a dark blue ketyl radical), lithium

aluminum hydride (LiAlH4) or phosphorous pentoxide (P4O10) are used to chemically destroy the

water.

The drying agents commonly used in the organic laboratories are calcium chloride (CaCl2),

sodium sulfate (Na2SO4) Calcium sulfate (CaSO4, as Drierite (R)) and magnesium sulfate

(MgSO4), all in their anhydrous form.

Listed below are the drying agents that are commonly used.Organic liquids are considered to be

wet if they contain water. Realize that the organic liquid will still be a liquid after it is dried.

Activated alumina ¹ is a very porous form of aluminum oxide of high surface area which adsorbs

liquids and gases without any change in form. Activated alumina will not soften or disintegrate

when immersed in liquids. Activated alumina may be regenerated to its original adsorption

efficiency by heating to a temperature between (177-316°C).

Reconditioning of mineral oils like transformer or insulating oils. Removal of oil vapor mist from

compressed air. Drying of organic liquids to a moisture level of 10 ppm or below. Drying of

various liquids such as Benzene, Carbon, Tetrachloride, Chlorobenzene, Ethyl Acetate,

Transformer oil, Vegetable oils etc.

Solvents drying guide

TO DRY USE ONE OF THE FOLLOWING DRYING AGENTS

AlcoholsAnhydrous forms of potassium carbonate; anhydrous magnesium or

calcium sulphate; quicklime.

Alkyl halides

Aryl halides

Anhydrous calcium chloride; anhydrous forms of sodium sulphate,

magnesium sulphate, or calcium sulphate; sodium pentoxide.

Saturated and

Aromatic

hydrocarbons

Anhydrous calcium chloride or sulphate; metallic sodium; phosphorus

pentoxide.

Aldehydes Anhydrous sodium sulphate; anhydrous magnesium or calcium sulphate.

KetonesAnhydrous sodium sulphate; anhydrous magnesium or calcium sulphate;

anhydrous potassium carbonate.

Organic bases

(amines)Solid potassium or sodium hydroxide; quicklime; barium oxide.

Organic acids Anhydrous sodium sulphate; anhydrous magnesium or calcium sulphate.

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Solvents: Properties and Drying agents

Solvent

Boiling

Pt.

°C

Density

Flash

Pt.

°C

Drying agent

Acetone 56 0.791 -18 K2CO3; Molecular sieve 0.3nm; CaCl2

Acetic acid 118 1.049 +40 P2O5; CuSO4

Acetic anhydride 136 1.082 +49 CaCl2

Acetonitrile 82 0.782 +6CaCl2; P2O5; K2CO3; calcium hydride;

Molecular sieve 0.3nm

Aniline 184 1.022 +76 KOH; BaO

Anisole 154 0.995 +51 CaCl2; Na; distillation

Benzene 80 0.879 -10CaCl2; distillation; Na; Pb/Na; ; calcium

hydride; Na wire; Molecular sieve 0.4nm

1-Butanol 117 0.810 +29 K2CO3; distillation

2-Butanol 100 0.808 +24 K2CO3; distillation

tert-Butanol 82 0.882 +11 CaO; Freezing

n-Butyl acetate 127 0.882 +33 MgSO4;

Carbon disulphide 46 1.263 -30 CaCl2P2O5;

Carbon tetrachloride 77 1.594 nonedistillation; P2O3; Pb/Na; Molecular sieve

0.4nm

Chlorobenzene 132 1.106 +29 CaCl2; distillation;P2O5

Chloroform 62 1.486 noneCaCl2; P2O5; Pb/Na; Molecular sieve

0.4nm

Cyclohexane 81 0.799 noneNa; Na/Pb; LiAlH4; Molecular sieve

0.4nm

Cyclohexanone 155 na na Distillation

Decahydronaphthalene

(Dekalin)~190 0.886 <54 CaCl2; Na; Pb/Na

Dichloromethane 40 1.325 noneCaCl2; Pb/Na; calcium hydride;

Molecular sieve 0.4nm

Dicyclopentadiene:

(cyclopentadiene dimer)170 na na

Refractionation: distillate at 40 - 42°C.

(Use at once! or keep in dry ice/acetone

bath no longer than 1 Hr.)

Diethyl carbonate 126 0.975 +25 Na2SO4; K2CO3

Diethylene glycoldibutyl

ether225 0.885 +118 CaCl2; Na

Diethylene glycol

dimethyl ether

155

1650.906 +70 CaCl2; Na

Diethyl ether 34 0.714 -40

CaCl2; Na; Pb/Na; LiAlH4; Na

wire/benzophenone; Molecular sieve

0.4nm

Di-isopropyl ether 68 0.726 -23 CaCl2; Na; Molecular sieve 0.4nm

Dimethyl formamide 153 0.950 +62 distillation; Molecular sieve 0.4nm

Dimethyl sulfoxide 189 1.101 +95 distillation; Molecular sieve 0.4nm

1,4 Dioxane 101 1.034 +11.8 CaCl2; Na; Molecular sieve 0.4nm

Ethanol 79 0.791 +12 CaO; Mg; MgO; Molecular sieve 0.3nm

Ethyl acetate 77 0.901 -4K2CO3; P2O5; Na2SO4; calcium hydride;

Molecular sieve 0.4nm

Ethylenediamine:

(1-2 diaminoethane)118 na na Simple distillation.

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Solvent

Boiling

Pt.

°C

Density

Flash

Pt.

°C

Drying agent

Ethylene glycol 197 1.109 +111 distillation; Na2SO4

Ethylene glycol monoethyl

ether135 0.930 +41 distillation

Ethylene glycol

monomethyl ether125 0.965 +52 distillation

Ethyl formate 54 0.924 -20 MgSO4; Na2SO4;

Formamide 211 1.134 155 Na2SO4; CaO

Glycerol 290 1.260 +176 distillation

Heptane 98 0.684 -4 calcium hydride; Na wire

n-Hexane 69 0.659 -23

Na; Pb/Na; LiAlH4; calcium hydride;

Na wire/benzophenone; Molecular

sieve 0.4nm

Isobutanol 108 0.803 +28 K2CO3; CaO; Mg;

Isobutyl methyl ketone 117 0.801 +15.5-4 K2CO3;

Methanol 65 0.792 +11 Mg; CaO; Molecular sieve 0.3nm

Methyl acetate 57 0.933 -10 K2CO3; CaO;

1-Methyl-2-pyrrolidone 202 1.026 +95Na2SO4; distillation; Molecular sieve

0.4nm

Methyl Ethyl ketone 80 0.806 -44 K2CO3;

Nitrobenzene 211 1.204 +92 CaCl2; P2O5; distillation;

n-Pentane 36 0.626 -49 Na; Pb/Na;calcium hydride; Na wire

Pet ether mixture na na

calcium hydride; Na

wire/benzophenone; Molecular sieve

type 4A

1- Propanol 97 0.804 +15 CaO; Mg

2-Propanol 82 0.785 +12 CaO; Mg; Molecular sieve 0.3nm

Pyridine 116 0.982 +20 KOH; BaO; Molecular sieve 0.4nm

Tetrahydrofuran 66 0.887 -17.5 Molecular sieve 0.4nm

Tetrahydronaphthalene

(Tetralin)208 0.973 CaCl2; Na

Thionyl chloride 48 na na Redistill.

Toluene 111 0.867 +4distillation; Ca; CaCl2; Na; Molecular

sieve 0.4nm

Trichloroethylene 87 1.462 none distillation; Na2SO4; K2CO3

Xylene 137/140 -0.86 +25distillation; Na; CaCl2; Molecular sieve

0.4nm

Reference: http://www.deltaadsorbents.com/activated_alumina_2.php

delloyd.50megs.com

Signature: Dhanlal De Lloyd, Chem. Dept, The University of The West Indies, St. Augustine campusThe Republic of Trinidad and Tobago.

Copyright: delloyd2000© All rights reserved.

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