Coniferous lignin

Since it is generally viewed that coniferous lignin has almost 40% of its linkages connected via 0-O-4 bonds, these aforementioned results suggest that a lignin polymer connected primarily via such linkages should... 

Guaiacylglycerol-/3-coniferyl ether is a dimeric decomposition product of coniferous lignin dehydrodivanillin may be also formed by dimerization of vanillin after formation from lignin. Among the lignin decomposition products are mono-, di- and triphenol derivatives which are derived from the different types of lignin of needle trees, deciduous trees, or graminees. 

Table II also lists the C.O.P. value of coniferyl alcohol, the basic lignin building stone of coniferous lignins. The low value indicates the rather...

Nahum LS (1969) Estimation of double bond content in lignin from the results of the oxo reaction of wood and lignin model compounds Tappi 52 712-714 Pew JC, Connors WJ (1971) Color of coniferous lignin Tappi 54 245-251 Redinger L (1961) Alkali lignin, its condensation products with phenols, and preparation of curable resins Monatsber Dtsch Akad Wiss (Berl) 3 571-578 Richtzenhain H, van Hofe C (1939) A stilbene derivative from the sulfite waste liquor Chem Ber 72 1890-1892... 

Figure 1.5. Polymeric structures in coniferous lignin and cellulose.

Coniferous lignin contains 2% benzyl groups of the phenolic type and 6% of the alkanoic type (see Fig. 10). About 0.24 oxygen atoms in lignin are present as benzyl alcohols or benzyl aryl ethers. These groups are involved in the delignification reactions in chemical pulping operations. 

Cross and Bevan Cellulose- An impure cellulose isolated from the complex it forms with lignin, in materials such as wood straw. The method of isolation is described by Doree (Ref 1) Ott (Ref 2). Cross Bevan cellulose contains both furfural-yielding substances (pentosans), and hexosans of the mannan type. It retains, in the case of coniferous woods, 40-60% of the total furfural-yielding substances in the original wood, and about 55 66% iq the case of hard woods. 

The ratio of vanillin to vanillic acid and the yields of these two products, expressed as percentages of wood lignin, are the most significant data available to judge the severity of an alkaline nitrobenzene oxidation of a coniferous wood. The yields of vanillin and vanillic acid reported in Tables IV and V as methyl ether and methyl ether ester are only approximately 8 and 50%, respectively, of amounts that might be expected based on previous work. The ratio of vanillin to vanillic acid has been found to be 8 1 whereas in the reaction reported here it is 1 2. Furthermore, Leopold 32) reported vanillin vanillic acid oxalic acid as 6 1 2 whereas... 

Chemical pulp starts with logs that have had their bark peeled off and that have been reduced to chips. The wood chips are boiled in strong caustic solutions that dissolve away parts of the wood that are not cellulose, such as lignin and resin, and leave the cellulose fibers more or less free. There are two chief processes for producing chemical pulp the kraft process, and the sulfite process. The kraft process uses the wood of either deciduous (e.g., poplar) or coniferous trees (e.g., spruce, fir, and hemlock) and produces a very strong paper. The sul-... 

Coniferin (20) is one of the most abundant lignan glycosides occurring mostly in coniferous trees and some other plants. It is the dominant transport and storage form of coniferyl alcohol, which in turn constitutes the main building block of lignins. 

VIII. Ae-Studies on Braun s Native Lignins from Coniferous Woods. Svensk Papperstidn. 61 187-210, 1958. 

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