Soda lignin

Separation and Characterization of the Vanillin Compound from Soda Lignin... 

Keywords Black liquor, crystallization process, oil palm empty fmit bunches, soda lignin, vanillin... 

In this study the percentage of vanilhn present in the soda lignin sample will be determined. Next, the vanillin compound will be separated from soda lignin via crystallization technique. 

The pH of the obtained black liquor was 12. 45 and its density 1.02 g/iuL. The soda lignin was then precipitated from the concentrated black hquor by acidifying it to pH 2 using 20% concentrated sulfuric acid (H SO ). The precipitated hgnin was then filtered and washed with water adjusted to pH 2 using H SO. Then, the soda lignin was dried in a vacuum oven at 55°C for 24 hours prior to further analysis [12]. 

Nitrobenzene oxidation was carried out by adding 50 mg of dry soda lignin into a mixture of 7 mL of 2 M NaOH and 4 ttiL of nitrobenzene in a 15 ttiL steel autoclave. Then, the antoclave was heated to 165°C for 3 hours in a preheated thermostat oil bath. After the autoclave was cooled to room temperature, the mixture was then transferred to a liqnid-hquid extractor for continuous extraction with chloroform (5 x 20 mL) in order to remove any nitrobenzene reduction product and excess nitrobenzene. The oxidation mixtnre was then acidified by concentrated HCl to pH 3 and further extracted with chloroform (5x15 mL). The solvent from the second chloroform solution was then removed using a rotary evaporator at 40°C under reduced pressure in order to obtain the nitrobenzene oxidation mixture. The mixture was then dissolved into dicloromethane and made up to 10 luL. This mixture was then used as a stock solution for high performance liquid chromatography (HPLC) analysis [6]. 

Sodium bisulfite-china clay proved to be an efficient initiator for homopolymerization and graft polymerization of methyl methacrylate onto cellulose. Grafting reactions using ceric ammonium sulfate, sodium bisulfite-soda lime glass or -china clay are inhibited or retarded on adding soda lignin to the grafting medium. 

Preparation of Materials. Soda lignin was prepared from bagasse by subjecting to soda cooking conditions (11), namely,... 

Addition of 1.33% of soda lignin to the grafting systems inhibited the grafting reactions completely (zero grafting yields) (Figures 1, 3, 4 and 5). 

Particular attention has been devoted to the fate of Cf,C2 enol ether structures present in kraft or soda lignins (Gellerstedt et al. 1984). It has been shown that such structures are essentially converted to a C(,C2 product with two thioethyl groups at C. This dithioacetal compound is formed only in small amounts on thioacidolysis of QC3 y -aryl ether structures. Therefore, when present in significant amounts in the thioacidolyzate of a sample, the dithioacetal compound is indicative of 02 enol ether structures preexisting in the sample. 

The application of C NMR techniques to the characterization of soda lignin confirmed that formaldehyde was released from the y-hydroxymethyl groups of C9 units during pulping via reverse aldol reactions with subsequent formation of vinyl ether structures in the lignin matrix [387]. Furthermore, in the same study, it was confirmed... 

The components of lignin obtained are listed in Table 9.1 and labeled alphabetically in Fig. 9.1. The standard solntion for each expected component to be present in lignin was injected into three different concentrations, 10,100 and 1,000 ppm. This was done to ensure that the solution for each similar component at different concentrations had the same retention time. From the HPLC chromatogram, six components were detected in the soda lignin. They are vanillin, syringaldehyde,... 

Zakzeski J, Jongerius AL, Weckhuysen BM (2010) Transition metal catalyzed oxidation of Alcell lignin, soda lignin, and lignin model compounds in ionic liquids. Green Chem 12 1225... 

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