ABSTRACT
Introduction ............................................................................................................268 Bonding Patterns and Functional Groups .............................................................. 272
General .............................................................................................................. 272 Survey of Different Types of Lignin Units ........................................................ 272
Arylglycerol Units Attached to an Adjacent Unit by a β-O-4 Linkage ...... 272 Noncyclic Benzyl Aryl Ethers ...................................................................... 274 Biphenyl, Dibenzodioxocin, and Diaryl Ether Structures ............................ 275 Phenylpropane Units Attached to an Adjacent Unit by a β-5 Linkage ........ 276 Phenylpropane Units Attached to an Adjacent Unit by a β-β Linkage ........ 277 1-Aryl-2-aryloxy-1-propanone Units ........................................................... 278 Phenylpropane Units Attached to an Adjacent Unit by a β-1 Linkage ........ 279 Phenylpropane Units Linked to an Adjacent Unit by a β-6 or α-6 Linkage ............................................................................................... 280 Cyclohexadienone Units and Quinoid Units ................................................ 281 End-Groups .................................................................................................. 281 Esteried Units .............................................................................................284 Additional Lignin Units ...............................................................................284
