PURIFICATION OF LABORATORY CHEMICALS pot

PURIFICATION OF
LABORATORY CHEMICALS
Wilfred L. F.Armarego
Christina U Un Chai
COMMON PHYSICAL TECHNIQUES USED IN PURIFICATION 1
INTRODUCTION 1
THE QUESTION OF PURITY 1
SOURCES OF IMPURITIES 3
PRACTICES TO AVOID IMPURITIES 3
Cleaning practice 3
Silylation of glassware and plasticware .4
SAFETY PRECAUTIONS ASSOCIATED WITH THE PURIFICATION
OF LABORATORY CHEMICALS 4
SOME HAZARDS OF CHEMICAL MANIPULATION IN PURIFICATION AND
RECOVERY OF RESIDUES 5
Perchlorates and perchloric acid 5
Peroxides 5
Heavy -metal-containing explosives 5
Strong acids 6
Picric acid 6
Reactive halides and anhydrides 6
Salts and organic esters of some inorganic acids 6
Solvents 6
METHODS OF PURIFICATION OF REAGENTS AND SOLVENTS 7
SOLVENT EXTRACTION AND DISTRIBUTION 7
DISTILLATION 8
Techniques 8
Distillation of liquid mixtures 9
Types of distillation 10
The distilling flask 10
Types of columns and packings 10

Types of condensers 11
Vacuum distillation 11
Spinning-band distillation 12
Steam distillation 12
Azeotropic distillation 13
Kugelrohr distillation 13
Isopiestic or isothermal distillation 14
RECRYST ALLIS ATION 14
Techniques 14
Filtration 15
Solvents 15
Choice of solvents 15
Water 16
Petroleum ethers 16
Mixed solvents 16
Recrystallisation from the melt 17
Zone refining 17
CHROMATOGRAPHy 18
Vapour phase chromatography (GC or gas-liquid chromatography) 18
Liquid chromatography 18
Adsorption chromatography 19
Thin layer chromatography (TLC) 19
Paper chromatography 20
Column chromatography 20
Graded adsorbents and solvents 20
Preparation and standardisation of alumina 20
Preparation of other adsorbents 21
Silica 21
Diatomaceous earth 21
Charcoal 21

Cellulose 21
Supelco products 21
Flash Chromatography (FC and HPFC) 22
Paired- ion Chromatography (PIC) 22
Ion-exchange Chromatography 23
Ion-exchange Resins 23
Ion-exchange celluloses and sephadex 24
Sephadex 24
Sepharose 24
Cellex CM 25
Cellex D 25
Crystalline hydroxylapatite 25
Gel filtration 25
High performance liquid chromatography (HPLC) 25
Other types of liquid chromatography 26
Automated column chromatography 27
ELECTROPHORESIS 27
DRyING 27
Removal of solvents 27
Removal of water 27
Intensity and capacity of common desiccants 28
Suitability of individual desiccants 28
Molecular sieves 30
MISCELLANEOUS TECHNIQUES 31
Freeze-pump-thaw and purging 31
Vacuum lines, Schlenk and glovebox techniques 31
PROPERTIES USEFUL IN PURIFICATION 32
Ionisation constants - pK 32
pK and temperature 33
pK and solvent 33

Solubilities of gases in liquids 33
CHEMICAL AND BIOCHEMICAL SOURCES 34
TABLES 34
TABLE 1.
FIGURE 1.
TABLE 2A.
TABLE 2B.
TABLE 3.
TABLE 4.
TABLE 5.
TABLE 6.
TABLE 7.
TABLE 8.
TABLE 9.
TABLE 10.
TABLE 11.
TABLE 12.
TABLE 13.
TABLE 14.
SOME COMMON IMMISCIBLE OR SLIGHTLY MISCIBLE
PAIRS OF SOLVENTS 34
NOMOGRAM 35
PREDICTED EFFECT OF PRESSURE ON BOILING POINT 36
PREDICTED EFFECT OF PRESSURE ON BOILING POINT 37
HEATING BATHS 38
WHA TMAN FILTER PAPERS 38
MICRO FILTERS 39
COMMON SOLVENTS USED IN RECRYSTALLISATION .40
PAIRS OF MISCIBLE SOLVENTS .40
MATERIALS FOR COOLING BATHS .41

LIQUIDS FOR STATIONARY PHASES IN GAS
CHROMATOGRAPHy 42
METHODS OF VISUALISATION OF TLC SPOTS .42
GRADED ADSORBENTS AND SOLVENTS .43
REPRESENTATIVE ION-EXCHANGE RESINS .43
MODIFIED FIBROUS CELLULOSES FOR ION-EXCHANGE 43
BEAD FORM ION-EXCHANGE PACKAGINGS .44
LIQUIDS FOR DRYING PISTOLS .44
VAPOUR PRESSURES (mm Hg) OF SATURATED AQUEOUS
SOLUTIONS IN EQUILIBRIUM WITH SOLID SALTS .45
DRYING AGENTS FOR CLASSES OF COMPOUNDS 46
STATIC DRYING FOR SELECTED LIQUIDS (25°C) 46
AQUEOUS BUFFERS 47
SOLUBILITY COEFFICIENTS OF AIR AT 1atm IN WATER .48
SOLUBILITY COEFFICIENTS OF O
2
AT 1atm IN WATER 48
BUNSEN COEFFICIENTS (~) OF GASES AT 1atm
IN ORGANIC SOLVENTS AT 20°C 48
OSTWALD COEFFICIENTS
(l)/L
OF O
2
AT 1atm
IN AQUEOUS SOLUTIONS AT 25°C .49
SOLUBILITIES OF HCI AND NH
3
AT 760mm (g/lOOg OF
SOLUTION) 50
BOILING POINTS OF SOME USEFUL GASES AT 760 mm 50

PREFIXES FOR QUANTITIES 50
BIBLIOGRAPHy 51
TABLE
15.
TABLE
16.
TABLE
17.
TABLE 18.
TABLE 19.
TABLE 20.
TABLE
21.
TABLE 22.
TABLE
23.
TABLE 24.
TABLE 25.
TABLE
26.
CHEMICAL METHODS USED IN PURIFICATION 61
GENERAL REMARKS 61
REMOVAL OF TRACES OF METALS FROM REAGENTS 61
METAL IMPURITIES 61
DISTILLATION 61
SCAVENGER RESINS AND OTHER SUPPORTS 62
USE OF ION EXCHANGE RESINS 62
PRECIPITATION 62
Removal of lead contaminants 62
Removal of iron contaminants 62

Removal of other metal contaminants 63
EXTRACTION 63
COMPLEXATION 63
USE OF METAL HYDRIDES 63
LITHIUM ALUMINIUM HYDRIDE 63
CALCIUM HyDRIDE 63
SODIUM BOROHYDRIDE 63
POTASSIUM BOROHYDRIDE 64
PURIFICATION via DERIV ATIVES 64
ALCOHOLS 64
ALDEHYDES 65
AMINES 65
Picrates 65
Salts 65
Double salts 66
N- Acetyl derivatives 66
N- Tosy I derivatives 66
AROMATIC HyDROCARBONS 66
Adducts 66
Sulfonation 66
CARBOXYLIC ACIDS 66
4-Bromophenacy I esters 66
Alkyl esters 66
Salts 67
HYDRO PEROXIDES 67
KETONES 67
Bisulfite adduct 67
Semicarbazones 67
PHENOLS 67
Benzoates 67

Acetates 68
PHOSPHATE AND PHOSPHONATE ESTERS 68
MISCELLANEOUS 68
GENERAL METHODS FOR THE PURIFICATION OF CLASSES OF COMPOUNDS 68
PROCEDURES 68
CRITERIA OF PURITY 69
GENERAL PROCEDURES FOR THE PURIFICATION OF SOME CLASSES OF
ORGANIC COMPOUNDS 69
ACETALS 70
ACIDS 70
Carboxylic acids 70
Sulfonic acids 70
Sulfinic acids 70
ACID CHLORIDES 71
ALCOHOLS 71
Monohydric alcohols , 71
Polyhydric alcohols 71
ALDEHYDES 71
AMIDES 71
AMINES 72
AMINO ACIDS 72
ANHYDRIDES 72
CAROTENOIDS 72
ESTERS 73
ETHERS 73
HALIDES 74
HyDROCARBONS 74
IMIDES 75
IMINO COMPOUNDS 75
KETONES 75

MACROMOLECULES 75
NITRILES 75
NITRO COMPOUNDS 76
NUCLEIC ACIDS 76
PHENOLS 76
POLYPEPTIDES AND PROTEINS 76
QUINONES 76
SALTS 76
With metal ions 76
With organic cations 77
With sodium alkane sulfonates 77
SULFUR COMPOUNDS 77
Disulfides 77
Sulfones 77
Sulfoxides 77
Thioethers (sulfides) 77
Thiols 77
Thiolsulfonates (disulfoxides) 77
THE FUTURE OF PURIFICATION 80
INTRODUCTION 80
ORGANOCATAL YSIS 80
MICROWAVE TECHNOLOGIES 81
SOLID PHASE SyNTHESIS 81
SOLID PHASE PEPTIDE SYNTHESIS (SPPS) 82
SOLID PHASE DEOXYRIBONUCLEOTIDE SYNTHESIS 82
POLYMER SUPPORTED REACTANTS 82
SCAVENGER RESINS 82
COMBINATORIAL CHEMISTRy 83
ALTERNATIVE SOLVENTS 83
SUPERCRITICAL FLUIDS 83

IONIC LIQUIDS 84
FLUOROUS CHEMISTRY 84
BIBLIOGRAPHy 85
PURIFICATION OF ORGANIC CHEMICALS
INTRODUCTION 88
ALIPHATIC COMPOUNDS 89
ALICYCLIC COMPOUNDS 194
AROMATIC COMPOUNDS 223
HETEROCYCLIC COMPOUNDS 353
PURIFICATION OF INORGANIC AND
METAL· ORGANIC
CHEMICALS
(Including Organic compounds of B, Bi, P, Se, Si, and ammonium and
metal salts of organic acids)
INTRODUCTION 445
INORGANIC COMPOUNDS 446
METAL-ORGANIC COMPOUNDS 505
PURIFICATION OF BIOCHEMICALS AND RELATED PRODUCTS
INTRODUCTION 577
AMINO ACIDS and PEPTIDES 583
PROTEINS, ENZYMES, DNA and RNA 607
CAROTENOIDS 625
CARBOHyDRATES 631
STEROIDS 650
MISCELLANEOUS COMPOUNDS (including biologically useful reagents,
Low-molecular-weight bioactive substances, antibiotics, coenzymes, vitamins,
lipids, phospholipids, nucleosides, nucleotides and polynucleotides) 662