Calculation of lignin

Steps in the calculation of lignin content based on the assumed absorptivity of softwood of lignin (Fergus et al. 1969) are as follows ... 

Calculation of Lignin Concentration from Refractive Index... 

Boutelje JB (1972) Calculation of lignin concentration and porosity of cell wall regions by interference microscopy Sven Papperstidn 75 683-686... 

Figure 1. Absorption spectra of lignin peoxidase oxycomplex and compound II. Also shown is the calculated spectra of the mixtures of oxycomplex and compound II. In descending order of the Soret peak extinction coefficient, 100% oxycomplex (416 nm) is shown in solid line the mixture of 75% oxycomplex and 25% compound II (417 nm) in long dashed line the mixture of 50% oxycomplex and 50% compound II (417 nm) in dotted line the mixture of 25% oxycomplex and 75% compound II (419 nm) in dashed-dot line and 100% compound II (420 nm) in me um dashed line.

Mathematical Treatment of the Results. In almost all experiments inactivation followed first order kinetics with a high correlation. The half-lives of lignin peroxidase were calculated from the following equation, where k is a rate constant of inactivation ... 

Figure 4. Half-lives of lignin peroxidase as a function of pH at different temperatures. Calculated half-lives 30X O 40 C A 50 C 60 C. Experimentally obtained half-lives 30 C 40 C 50 C X 60 C.

Computational and theoretical techniques have been used to describe a wide range of compound classes, but have been only sparingly utilized in studies on the properties and reactions of lignin. A brief summary of the capabilities and limitations of molecular mechanics and molecular orbital calculations is presented, along with a survey of specific applications to lignin that have been reported in the literature. 

A calculation for the U.S. market showed that the whole demand of aromatics (BTX 20 million tons/year) could be optimally produced by an input of approximately 42 million tons/year. Due to the currently low effectiveness of only 10%, the needed amount would be 420 million tons/year of lignin [17]. 

Calculated as lignin. The estimated values for lignosulfonates are given in parentheses (calculated by assuming the degree of sulfonation to be 2.5 meq/g lignin). 

In contrast to the approach utilized in the direct determination of lignin, indirect methods do not involve the isolation of a lignin residue. Instead, the lignin content may be calculated as the difference between 100% and the polysaccharide content of an extractive-free sample or, more commonly, by measuring some characteristic structural functionality, property, or chemical response and relating the result to concentration. 

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