Hydrogenolysis to Monomeric Products

Wood is ground to 2-mesh in a Wiley mill, extracted 48 h in a Soxhlet extractor with ethanol-benzene (1 1, v/v), and air-dried. 

Raney nickel catalyst is prepared as described by Pavlic and Adkins (1946) with the exception that the washing under a hydrogen atmosphere is omitted. The catalyst is stored under cold dioxane previously purified by distillation over metallic sodium (Fieser 1955) or lithium aluminum hydride (Augustine and Caputo 1965). 

Compounds represented by the four major peaks are collected and identified by comparison of the IR spectra, refractive indices, and retention times with those of authentic samples of probable hydrogenolysis monomers Other components of the mixture are identified by matching retention times and relative retention times with those of authentic reference compounds (Note 2) 

Note 1 As a consequence of the continuing development of separation techniques and equipment, the resolution of lignin hydrogenolysis product mixtures is not restricted to the foregoing set of conditions but may be achieved equally well with other equipment and combinations of conditions 

Note 2. The identification techniques which comprise part of the original procedure may be supplemented or supplanted with NMR and mass spectrometric methods of analysis (Faix and Meier 1987). 

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