Hydrogenolysis Lignin

The most significant conclusion that may be drawn from these results is that palladium-charcoal exhibits similar catalytic properties as does Raney nickel if used under similar conditions. The same types of lignin hydrogenolysis products are obtained, and as before the major fraction under neutral conditions is the phenylpropanol derivative, dihydro-coniferyl alcohol. With a minimum temperature ca. 150°C. required for any reaction to occur and an optimum temperature ca. 195°C. for maxi-... 

Hydrogenolysis has also found use in a lignin biosynthesis study in which 14C-labeled lignin precursors were administered to wheat plants and maple twigs and ultimately recovered in the form of the typical lignin hydrogenolysis products, dihydroconiferyl and dihydrosinapyl alcohols (Brown and Neish 1959). 

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... 

As most of the dimeric and trimeric lignin hydrogenolysis products are found in the ES-fraction, the procedure for this fractionation is described in detail procedures for the other separations shown in Fig. 6.5.3 may be obtained by consulting the original literature source (see Table 6.5.2). 

Table 6.5.2. Fraction source for dimeric and trimeric lignin hydrogenolysis products ...

Klemola A, Pepper JM (1969) 2-(2 Methoxy-4 n-propylphenoxy) propan-1 ol as a new spruce lignin hydrogenolysis product Chem Commun 1048 Lai YZ, Sarkanen KV (1971) Isolation and structural studies In Sarkanen KV, Ludwig CH (eds) Lignins Occurrence, formation, structure and reactions Wiley-Interscience, New York, 182-185... 

Hydrogenolysis of Lignin Model Compounds Using In-Situ, Water-Soluble Ru/P(CH2OH)3... 

Lignin-derived compounds have been observed in pyrolysis products of low rank coals and associate woody tissue FI- 61. Mycke and Michaelis [2] isolated lignin-derived methoxyphenols from a Miocene coal by catalytic hydrogenolysis. Sigleo [S] reported the presence of phenolic compounds derived from iteration of lignin in pyrolysis products of silicified woody tissue as old as Triassic age. However,... 

Areas of uncertainty in this method of analyzing modified lignins include the problem that little more than one-third of the lignin is converted to volatile products by the hydrogenolysis reaction the non-volatile fraction cannot be analyzed by VPC/MS. This will constitute a difficulty only if the... 

TVTuclear magnetic resonance spectroscopy was used to determine struc- tural features in lignin and lignin fractions isolated from the hardwood Alnus rubra by mild catalytic hydrogenolysis. 

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