استخراج ليگنين از ضايعات حاصل از چوب و تهيه وانيلين از آن

Extraction of lignin from wood dust and preparation of vanillin from it

Lignins are phenolic polymers found in plant cell walls , which are responsible, with cellulose, for the stiffness and rigidity of plant stems. Especially associated with woody plants, up to 30% of organic matter of trees consists of lignins. Vanillin is a colorless , crystalline with a typical vanilla odor that is prepared from Vanilla planifollia, isoeugenole, and coniferyl alcohol. In this research, lignin was extracted by different methods from wood dust and preparation of vanillin from lignin was performed by a semisynthetic procedure. Lignin was extracted by a different solvent mixture such as, (Ethanol-Benzene-H2O) and (Dioxan-H2O- HCl) in different conditions; finally the wood dust was extracted by (benzene - ethanol - H2O) with soxhlett and lignin was obtained. Then the lignin was treated with 72% H2SO4 by a modified method and diluted with 3% H2SO4. Lignin was reacted with nitrobenzene to get vanillin in a proper basic and oxidation condition at 160 °C. The total yield of the reaction was determined by gravimetric method. In this study FT-IR spectrum of lignin was similar to standard. The amounts of extracted lignin was 35%. The main application of vanillin is the flavoring of food and small quantities are used in perfumery to round and fix sweet, balsamic fragrance, and it is an important intermediate in the production of pharmaceutical aids, since the plant material source for preparing vanillin is not sufficient, it is needed to introduce some synthetic or semisynthetic procedures to obtain vanillin in a good yield, as we did in our research.