Ⅰ．Introduction 1
Ⅱ．The Evolution of Lignin Chemistry 5
Ⅲ．The Definition and Distribution of Lignin 14
Ⅳ．Color Reaction of Lignified Materials 24
A．Introduction 24
B．Preparation of the Material 24
C．Color Reactions with Aliphatic Compounds 25
D．Color Reactions with Phenolic Compounds 26
E．Color Reactions with Aromatic Amines 29
F．Color Reactions with Heterocyclic Compounds 30
G．Color Reactions with Inorganic Reagents 40
1．The M？ule Test 41
2．Other Color Reactions Involving Chlorination 42
3．Color Reactions with Inorganic Acids 43
4．Other Inorganic Color Reagents 44
H．Color Reactions with Dyestuffs 45
Ⅴ．The Isolation of Lignin 49
A．Preparation of the Plant Material 49
B．Native Lignin 51
C．Insoluble Lignins 54
1．Acid Lignins 54
a．Sulfuric Acid or Klason Lignin 55
ⅰ．Preparation of Sulfuric Acid Lignin 56
b．Hydrochloric Acid or Willst？tter Lignin 56
ⅰ．Preparation of Hydrochloric Acid Lignin 58
ⅱ．Modified Methods 59
c．Hydrofluoric Acid Lignin 60
2．Cuoxam or Freudenberg Lignin 61
a．Preparation of Cuoxam Lignin 62
3．Periodate or Purves Lignin 63
D．Organosolv Lignins 65
1．Alcohol Lignins 65
a．Methanol Lignin 66
b．Ethanol Lignin 69
c．Butanol and Amyl Alcohol Lignins 69
d．Cyclohexanol Lignin 70
e．Benzyl Alcohol Lignin 70
f．Glycol Lignins 70
g．Glycol Monomethyl Ether Lignin 74
h．Chlorohydrin Lignins 74
2．Aldehyde Lignins 76
a．Formaldehyde Lignin 76
b．Chloral Lignin 77
3．Ethyl Acetoacetate Lignin 77
4．Dioxane Lignins 78
5．Phenol Lignins 82
a．Unsubstituted Phenol Lignins 82
ⅰ．Preparation of Phenol Spruce Lignin 83
b．Substituted Phenol Lignins 85
6．Mercapto Lignins 85
a．Butylmercapto Lignin 86
b．Benzylmereapto Lignin 86
c．Thioglycolie Acid Lignin 87
ⅰ．Preparation of Thioglycolic Acid Lignin 87
7．Organic Acid Lignins 88
a．Formic Acid Lignin 88
b．Acetic Acid Lignin 89
ⅰ．Preparation of Acetic Acid Lignin 90
c．Chloroacetic Acid Lignins 93
d．Other Organic Acid Lignins 94
8．Organic Amine Lignins 94
E．Lignins Extracted with Inorganic Reagents 96
1．Introduction 96
2．Lignins Isolated by Alkaline Reagents 96
a．Ammonia Lignin 96
b．Hydrazino Lignin 97
c．Alkali or Soda Lignins 98
ⅰ．Isolated with Aqueous Alkaline Solutions 98
ⅱ．Commercial Alkali Lignins 105
ⅲ．Isolated with Alcoholic Alkaline Solutions 107
d．Thiolignin 108
3．Lignin Isolated by Bisulfites 111
a．Lignosulfonic Acid 111
ⅰ．Isolation as Basic Lignosulfonate 112
ⅱ．Isolation by the Salting Out Method 115
ⅲ．Isolation by Dialysis 123
F．Lignin Isolated by Hydrotropic Solvents 125
G．Lignin Isolated by a Mild Hydrogenation 126
Ⅵ．The Determination of Lignin 133
A．Introduction 133
B．Interfering Substances 134
1．Polysaccharides 134
2．Pectins 137
3．Proteins 137
4．Fats,Waxes,and Resins 138
5．Tannins and Phlobaphenes 138
6．Coloring Matters 139
7．Other Organic Substances 139
8．Inorganic Matters 139
C．The Effect of Pretreatments on the Lignin Determination 140
1．Organic Solvents 140
2．Water 140
3．Dilute Alkali 142
4．Dilute Acid(Prehydrolysis) 145
5．Summary 148
D．Preparation of the Sample 149
E．Lignin Determination Methods 151
1．Direct Methods 151
a．Determination with Strong Mineral Acids 151
ⅰ．Sulfuric Acid Method 151
ⅱ．Hydrochloric Acid Method 159
ⅲ．Hydrofluoric Acid Method 162
ⅳ．Mixed Acids 162
b．Determination as Alkali Lignin 164
2．Indirect Methods 164
a．By Removing the Lignin and Weighing the Carbo-hydrate Residue 164
b．By Reaction with Halogens 166
c．By Reduction of Nitric Acid 168
d．By Determining the Methoxyl Content 169
e．By the Reaction with Phloroglucinol 170
f．Mehta＇s Colorimetric Method 170
g．By Extraction with Phenol 171
3．Determination of Lignin in Spent Liquors 171
a．Lignin in Soda and Sulfate Spent Liquor 172
b．Lignin in Sulfite Spent Liquor 172
F．Comparison of Lignin Determination Methods 173
Ⅶ．The Physical Properties of Lignin 182
A．Introduction 182
B．Solubility 183
C．Melting Point 184
D．Heat of Combustion 185
E．Color 185
F．Density 185
G．Viscosity 186
H．Molecular Weight 188
1．Determination of the Unit Molecular Weight by Chemical Means 189
2．Determination of the Molecular Weight by Physical Means 191
3．Molecular Weight of Lignosulfonic Acids 195
I．Spreading Experiments 197
J．The Colloidal Nature of Lignin 199
K．The Conductivity of Lignosulfonic Acid 208
L．X-Ray Investigations of Lignin 211
M．Refractive Index 215
N．Optical Activity 215
O．The Fluorescence of Lignin 216
P．Ultraviolet Absorption Spectra 217
Q．Infrared Absorption Spectra 230
Ⅷ．The Elementary Composition and Constituent Groups of Lignin 236
A．Elementary Composition 236
B．The Phenylpropane Carbon Structure 242
C．Methoxyl Groups 243
D．Methylenedioxy Group 246
E．Hydroxyl Groups 246
F．Aromatic Hydrogen Atoms 254
G．The Carbonyl Group 255
H．Terminal CH3C-Groups 259
I．Double Bonds 260
Ⅸ．The Acylation and Acylysis of Lignin 270
A．Acylation 270
1．Introduction 270
2．Protolignin 271
3．Isolated Lignins 271
a．Insoluble Lignins 271
b．Organosolv Lignins 274
e．Alkali Lignin 276
d．The Xanthation of Lignin 278
e．Lignosulfonic Acid 279
B．Acylysis 280
1．Formolysis 280
a．Protolignin 280
2．Acetolysis 281
a．Protolignin 281
ⅰ．With Acetic Acid in the Presence of Catalysts 281
ⅱ．With Acetic Anhydride in the Presence of a Catalyst 284
ⅲ．With Acetyl Bromide 286
b．Isolated Lignin 287
Ⅹ．The Alkylation of Lignin 291
A．Introduction 291
B．Protolignin 292
1．Diazomethane 292
2．Dimethyl Sulfate 292
C．Isolated Lignins 295
1．Isolated Native Spruce Lignin 295
2．Acid Lignins 297
3．Organosolv Lignins 298
4．Lignosulfonic Acid 303
D．The Stability of the Methoxyl Groups in Methylated Lignin 305
Ⅺ．The Halogenation of Lignin 309
A．Fluorination 309
B．Chlorination 309
1．Protolignin 309
a．In an Aqueous Medium 309
b．In Methanol 316
2．Isolated Lignin 318
a．In an Aqueous Medium with Chlorine Gas 318
b．In Organic Solvents with Chlorine Gas 319
c．With Other Chlorinating Agents 324
3．Lignosulfonic Acid 326
C．Bromination 327
1．Protolignin 327
2．Isolated Lignin 328
3．Lignosulfonic Acid 332
D．Iodination 333
1．Protolignin 333
2．Isolated Lignin 334
3．Lignosulfonic Acid 336
E．Thiocyanogenation 336
Ⅻ．The Nitration of Lignin 339
A．The Action of Nitric Acid on Protolignin 339
B．Nitrolignins from Isolated Lignins 347
C．The Nitration of Lignosulfonic Acid 353
D．Theoretical Aspects of the Nitration of Lignin 355
ⅩⅢ．The Sulfonation of Lignin 359
A．Introduction 359
B．Protolignin 361
1．With Sulfurous Acid 361
2．With Bisulfites 362
3．Sulfonation by Sulfolysis 366
4．The Effect of Pretreatment of Protolignin on its Sulfonation 367
C．Isolated Lignin 372
D．Reactive Groups in Lignosulfonic Acid 373
E．Theories on the Sulfonation of Lignin and the Sulfonation of Model Substances 377
F．Conclusions 389
ⅩⅣ．The Hydrolysis of Lignin 394
A．In an Aqueous Neutral Solution 394
B．In an Alkaline Medium 397
1．Protolignin 397
2．Isolated Lignins 400
3．Lignosulfonates 405
4．Alkali Lignin 416
a．Introduction 416
b．From Protolignin 416
c．From Isolated Lignin 422
5．Thiolignin 422
a．From Protolignin 422
b．From Isolated Lignin 428
c．The Reaction Mechanism between Lignin and Sodium Sulfides 428
C．Acid Hydrolysis 431
1．Demethylation of Lignin 432
ⅩⅤ．The Alcoholysis of Lignin 453
A．Introduction 453
B．Alcohol Lignins 453
1．Protolignin 453
a．The Action of Alcohols and Mineral Acids 453
b．Methanolysis 454
c．Ethanolysis 456
d．Alcoholysis with Other Alcohols 457
2．Isolated Lignins 458
3．Theories on the Formation of Alcohol Lignin 460
C．Polyalcohol Lignins 461
1．Protolignin 461
2．Isolated Lignins 463
D．Alcobolysis to Monomolecular Lignin Building Stones 465
ⅩⅥ．The Mercaptolysis of Lignin 483
A．Introduction 483
B．Protolignin 483
1．With Mercaptans 483
2．With Thioglycolic Acid 484
3．With Other Mercapto Fatty Acids 491
C．Isolated Lignins 491
D．The Reaction Mechanism 494
ⅩⅦ．The Phenolysis of Lignin 497
A．Protolignin 497
B．Isolated Lignins(Secondary Phenol Lignins) 502
C．The Reaction Mechanism of Phenol Lignin Formation 507
ⅩⅧ．Reduction,Hydrogenation,and Hydrogenolysis of Lignin 511
A．Reduction 511
1．Introduction 511
2．Reduction with Hydriodie Acid and Red Phosphorus 511
3．Reduction by the Wolff-Kishner Method 514
B．Hydrogenation and Hydrogenolysis 514
1．Introduction 514
2．Hydrogenation at Low Temperatures(below 300°C．) 516
a．In Neutral Solution 516
b．In Alkaline Solution 521
3．Pressure Hydrogenation at High Temperatures(over 300°C．) 526
a．In Neutral Solution,without Catalysts 526
b．In Neutral Solution,with Catalysts 528
c．In Alkaline Solution 529
d．With Primary Alcohols in the Presence of Alkali 531
ⅩⅨ．The Oxidation of Lignin 536
A．Introduction 536
B．Oxidation in a Neutral Solution 536
1．Protolignin 536
2．Isolated Lignin 538
3．Lignosulfonates 541
C．Oxidation in an Acid Medium 543
1．Protolignin 543
2．Isolated Lignin 544
D．Oxidation in an Alkaline Medium 546
1．Protolignin 546
2．Isolated Lignin 547
3．Vanillin Formation 552
ⅩⅩ．The Alkali Fusion of Lignin 563
A．Introduction 563
B．Protolignin and Isolated Lignins 563
C．Lignosulfonic Acids 571
ⅩⅪ．Special Reactions with Lignin 574
A．The Action of Benzaldehyde on Lignin 574
B．The Effect of Grignard Reagent on Lignin Preparations 574
C．The Action of Diazobenzenesulfonic Acid on Lignin 576
D．The Action of Potassium in Liquid Ammonia on Lignin 576
E．Condensation of Lignin with Nitrodimethylaniline 578
F．The Dehydrogenation of Lignin 578
G．Sulfuric Acid Lignin Ester 579
ⅩⅫ．The Thermal Decomposition of Lignin 581
A．Dry Distillation in the Absence of Catalysts 581
B．Dry Distillation in the Presence of Zinc Dust(Zinc Dust Distillation) 589
C．Destructive Distillation in the Presence of Silver 591
D．Thermal Decomposition in the Presence of Nickel 592
E．Destructive Distillation in the Presence of Hydrogenation Catalysts 594
F．Thermal Decomposition with Lime in the Presence of Alcohol 596
ⅩⅩⅢ．The Biological Decomposition of Lignin 599
A．By Digestive Microorganism(Metabolism of Lignin) 599
B．By Soil Microorganisms 603
C．By Wood-destroying Fungi 607
D．The Biological Decomposition of Lignosulfonates 614
E．Coal Formation 615
ⅩⅩⅣ．Theories on the Structure of Lignin 621
A．Introduction 621
B．Lignin Formulas without Basic Building Stones 621
1．Cross and Bevan＇s Formula 621
2．Dorée and Barton-Wright＇s Formula 624
3．Fuchs＇ Formulas 625
C．Lignin Formulas with Basic Building Stones 628
1．Klason＇s Theory 628
2．Kürschner＇s Lignin Formula 638
3．Pavolini＇s Formula 642
4．Rassow and Gabriel＇s Formula 643
5．Chambovet＇s Formula 643
6．Freudenberg＇s Theory 644
7．Hibbert＇s Theory 651
8．Erdtman＇s Theory 665
D．Conclusions 669
ⅩⅩⅤ．The Linkage of Lignin in the Plant 675
A．Introduction 675
B．Lignin in a Physical Mixture with Other Plant Constituents 675
C．Lignin in Chemical Combination with Other Plant Constituents 678
D．Conclusions 687
ⅩⅩⅥ．Theories on the Formation of Lignin 694
A．Introduction 694
B．Lignin,a Reaction Product Formed during its Isolation 695
C．The Formation of Lignin in the Growing Plant 707
D．Formation of Lignin by Direct Assimilation Synthesis 710
E．Cellulose as the Precursor of Lignin 710
F．Pentosans or Pentoses as Precursors of Lignin 712
G．Pectins as Precursors of Lignin 715
H．Water-soluble Sugars as Lignin Precursors 716
1．Wislicenus＇ Theory 716
2．The Jonas-Schrauth Theory 719
3．Phillips＇ Theory 728
4．Vanzetti＇s Theory 730
ⅩⅩⅦ．Synthetic Lignins 733
Appendix 742
A．Purification of Lignin Derivatives 742
B．Methoxyl Determinations in Lignin and Lignin Derivatives 744
C．Purification of Dioxane 745
D．Preparation of Cuprammonium Hydroxide Solution(Schweizer Reagent) 746
1．Analysis for Copper 746
2．Analysis for Ammonia 747
E．Preparation of Ethylenediamine Copper Hydroxide Solution 747
F．Preparation of Hydrogenation Catalysts 747
1．Nickel-Kieselguhr Catalyst 747
2．Raney Nickel Catalyst 747
3．Copper-Chromium Oxide Catalyst 748
G．Preparation of a Saturated Aqueous Chlorine Dioxide Solution 748
H．Preparation of Periodic Acid 749
Author Index 750
Subject Index 766