Methods for Purification of Commonly Used Solvents

Reagent	Purification Method
Acetal	Drying with Na to remove the alcohol and water, and polymerizing the aldehyde, followed by fractional distillation.
Acetamide	Crystallized with a mixture of acetone, benzene, chloroform, dioxane, methyl acetate or benzene-ethyl acetate (3:1 and 1:1).
Acetic acid 36%	It is reacted with water by adding acetic anhydride, heated in the presence of CrO3 (2g/100mL) at a temperature just below its boiling point for 1h, then fractionated.
Acetic acid glacial	Add 5% acetic anhydride and 2% CrO3 ,followed by reflux and fractional distillation.
Acetone	Dry with anhydrous calcium sulfate, then distill.
Acetonitrile	Dry with anhydrous K2CO3 for 24h, then dry with molecular sieve or boric anhydride for 24h, then distil.
Acetophenone	Dry with anhydrous CaSO4 or CaCl2 for several days, then fractionate under reduced pressure, carefully, slowly and partially crystallize from the liquid at 0 °C (avoid light and moisture)
Acetylacetone	A small amount of 2 mol/L NaOH is added in portions to shake, until the aqueous phase is weakly alkaline, and a small amount of acetic acid is removed. Then wash with water, dry with anhydrous sodium sulfate, and distill by using a Vigreux column.
Anisole	Adding Na or BaO to reflow with FeSO4 crystal
Benzene	Shake benzene and concentrated sulfuric acid compound, then shake with water, dilute NaOH and water, then dry (with P2O5, Na, LiA1H4, CaH2, 4XLinde molecular sieve or CaSO4, or through silica gel column, pre-dry with CaCl2), then distill.
Benzonitrile	Dry with CaSO4, CaCl2, MgSO4 or K2CO3, and then distill under reduced pressure in an all-glass apparatus.
Benzyl alcohol	It is usually carefully distilled under reduced pressure in the absence of air.
Bromobenzene	Wash thoroughly with concentrated sulfuric acid, then wash with 10% NaOH or NaHCO3 solution and water, dry with CaCl2 or Na2SO4
1,4-Butanediol	Crystallized twice with anhydrous ether/acetone
1-Butanol	Dry with MgSO4, CaO, K2CO3, Ca or NaOH solids, and reflux with Ca, iodine-activated Mg, aluminum amalgam or Na and distill.
Carbon disulfide	Place with bromine (0.5 mL/L) for 3-4h, shake with KOH solution, shake with copper scrap (to remove unreacted Br), and dry with CaCl2.
Carbon tetrachloride	Distill, and take distillate until it is clear ,the distilled CCl4 is stored with 5A molecular sieve.
Cumene	Wash with a small amount of concentrated sulfuric acid several times , then wash with water, 10% Na2CO3 solution and water, dry with MgSO4, MgCO3 or Na2SO4, and then fractionate.
Cyclohexane	Wash with concentrated sulfuric acid until the eluate is colorless, then wash with water, Na2CO3 solution or 5% NaOH, and finally wash with water until it is neutral, then dry with P2O5, Linde 4A molecular sieve, CaCl2 or MgSO4, then dry with Na and distill.
Cyclohexanone	Dry with MgSO4, CasO4, NazSO4 or Linde 13X molecular sieves and distill.
Decane	Shake with concentrated sulfuric acid, wash successively with water, NaHCO3 solution and water, dry with MgSO4, and reflux with Na and distill.
Dichloromethane	Shake with concentrated sulfuric acid until the acid layer remains colorless,and then wash with water, 5% Na2CO3 solution, NaHCO3 solution or NaOH solution and water. Pre-dry with CaCl2 and distill with CaSO4, CaH2 or P2O5.
Diethyl carbonate	Wash 100 mL of the product sequentially with 10% Na2CO3 solution (20mL), saturated CaCl2 solution (20mL) and water (30mL). After drying with solid CaCl2 for 1h (note the avoidance of prolonged contact, as it will slowly combine with CaCl2),then get fractionated. It can also be dried with MgSO4 and then get fractionated.
N,N-Dimethylformamide	Stir overnight with CaH2 (50g/L), then filter and distill under reduced pressure at 20 mmHg. The distilled DMF should be stored in a 3A type or 4A type molecular sieve.
Dimethyl sulfoxide	Place with activated alumina, BaO or CaSO4 overnight, then filter and distill with CaH2 under reduced pressure (about 12 mmHg), and store in type 4A molecular sieve.
1,4-Dioxane	Pre-dry with CaCl2 or sodium, then reflux pre-dried solvent with Na (10g/L) and benzophenone (2g/L,) under an inert atmosphere until the solution is blue. Distillate and store in the dark with a 4A molecular sieve.
Ethanol absolute	Pretreatment with concentrated sulfuric acid (3 mL/L) to remove the amine, pretreatment with KMnO4 to oxidize the aldehyde, followed by refluxing with KOH to resinize the aldehyde, and through silica gel (column) to remove traces of H3PO4 and other acidic impurities. Water can be removed by azeotropic distillation with dichloromethane or 2,2,4-trimethylpentane.
Ether	Repeatedly shake the 1 L of ether and 5-10mL solution containing 6g ferrous sulfate and 110mL aqueous solution containing 6mL concentrated sulfuric acid.
n-Hexane	Distill the dibenzophenone dissolved in tetraethylene glycol dimethyl ether in the presence of sodium in nitrogen.
Methanol	Add 2g sodium borohydride into 1.5L of methanol; then slowly and continuously inlet the argon gas. After refluxing the solution at 30 °C for 1 day, add 2g of fresh sodium tablets (sodium tablets were washed with methanol), and finally it should be refluxed for 1 day before distillation.
1-Methylnaphthalene	It is dried with calcium chloride for several days.
2-Methyl-1-propanol	It is dried by refluxing with calcium oxide and cerium oxide for several hours, followed by treatment with calcium or aluminum amalgam, and finally fractionated with p-aminobenzenesulfonic acid or tartaric acid.
2-Methylpyridine	Add 90mL of 2-methylpyridine to a mixture of 168g of anhydrous zinc chloride liquid and 42mL of concentrated hydrochloric acid, filter out the crystals of the complex, recrystallize twice by absolute ethyl alcohol, and release the free base by adding an excess of sodium hydroxide solution. Steam distill the complex, and add the solid sodium hydroxide to the fraction to form two layers, wherein the upper layer is dried with solid potassium hydroxide, and then stored with cerium oxide for several days, and finally be fractionated.
Methyl sulfide	Add 1250 mL of EtOH containing 1 mol of Hg(II)Cl2 into a boiling alcohol solution of methyl sulfide to obtain the correct ratio of 2(CH3)2S·3HgCl2. After recrystallizing the complex to a constant melting point, 500g of the complex is heated with 250 mL of concentrated HCl in 750mL of water. The methyl sulfide is separated, washed with water, and dried with CaCl2 and CaSO4. Finally, it is distilled under reduced pressure with Na.
Naphthalene	Reflux in the presence of Raney nickel in an ethanol solution, and use benzene as an eluent to separate naphthalene by carbon tetrachloride solvent chromatography on an alumina column.
Nitromethane	Impurities are removed by drying with calcium chloride.
Octane	The extraction is repeated with concentrated sulfuric acid or chlorosulfonic acid, washed with water, dried and finally distilled.
Petroleum ether(30～60°C)	After shaking a few times with concentrated sulfuric acid, then wash with 10% sulfuric acid and potassium permanganate solution to remove unsaturated hydrocarbons and aromatic impurities, then wash with water, sodium carbonate aqueous solution, and then wash with water. Dry and distill with calcium chloride or sodium sulfate.
Phenanthrene	It is first distilled in the presence of sodium, refluxed with maleic anhydride in xylene, crystallized with acetic acid, sublimed, and melted to obtain a pure product.
(+)-α-Pinene	It is distilled under reduced pressure in the presence of nitrogen and stored in the dark.
1-Propanol	Water can be removed by direct distillation by forming an azeotrope with propanol. The propylene alcohol is removed as 2,4-dinitrophenylhydrazine by the addition of bromine (15 mL/g).
Pyridine	It is dried with solid potassium hydroxide, sodium hydroxide, calcium oxide, cerium oxide or sodium, and then fractionated.
Quinoline	After drying with sodium sulfate, zinc powder is added for vacuum distillation.
Tetrahydrofuran	Reflow and distill with lithium aluminum hydride to remove water, peroxides, inhibitors and other impurities.
1,2,3,4-Tetrahydronaphthalene	It is first washed successively with concentrated sulfuric acid until the acid layer is colorless, then washed with 10% Na2CO3, washed with water, dried with CaSO4 or Na2SO4, filtered, refluxed under Na or BaO and distilled under reduced pressure.
Thiophene	It is washed first with a hydrochloric acid solution, then with water, dried with CaSO4 KOH, and then purified by column chromatography on silica gel or alumina.
Toluene	The toluene is dried with alumina, CaH2 and 4A molecular sieves (30 g/L), then distilled to remove 5% of the front fraction, and excess molecular sieve (3A, 4A) or sodium silk is added for storage.
Trichloromethane	It is dried by alkaline alumina column, or 4A molecular sieve.
Triethylamine	It is dried with CaSO4, LiAlH4, Linde 4A molecular sieve, CaH2, KOH, K2CO3, and then separately distill or add BaO, sodium, P2O5, CaH2 for distillation.
m-Xylene	Crystallize with solvents such as methanol, ethanol, isopropanol, acetone, methyl ethyl ketone, toluene, pentane or pentene.