Betulin containing products were obtained in a yield of about 40% from absolutely dry birch bark. The content of betulin in the products was 74-75% or 85-89% depending on the presence of sodium or potassium hydroxide, respectively. The one step method of extraction of high purity betulin (97.7%) is pre sented. Betulin was identified by physic chemical methods, i.e., elemental analysis, IR and NMR spectros copy, and electron scanning microscopy. The thermal characteristics of betulin were also studied. It was shown that betulin exhibits gastroprotective, hepatoprotective, and capillary strengthening properties.
The new process of abies ethanol lignin sulfation by a low-toxic mixture of sulfamic acid and urea in 1,4dioxane medium was optimized and the structure of sulfated ethanol lignin was studied. The process of lignin sulfation is described by a first-order equation in the temperature range 70-100˚C. The value of the rate constants are weakly dependent on the ratios of lignin and sulfating complex (SC-sulfamic acid-urea mixture). The activation energy of the sulfation process decreaseses from 95 kJ / mol to 24 kJ / mol with an increase in the content of the sulfating complex. The optimal conditions for sulfation of abies ethanol lignin with a high yield of water-soluble sulfated lignin ((100% of mass) with sulfur content of 7.9%) where found: temperature 95-100°С, L / SC ratio 1: 2,3-1:2,9 and the 2-hour duration of the process. The composition and structure of water-soluble sulfated ethanol lignin were proven by elemental analysis, FTIR spectroscopy, two-dimensional NMR spectroscopy and gel permeation chromatography. It was shown that only alcoholic OH-groups of ethanol lignin react with sulfation complex. Sulfated ethanol lignin has a higher molecular weight and a lower degree of polydispersity compared to the initial ethanol lignin .
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