Research On The Extraction And Utilization Technology Of Biologically Active Substances In White Birch Bark

White birch(Betula platyphylla) is one of the mainbroad-leave tree species in northeast forestry of China, it is an important forest resource in Heilongjiang Province. White birch bark is the main residues of the process of harvesting and processing of white birch, it is an important resource of raw material, containing a variety of biologically active substances. In this study, we use the white birch bark as raw material, applying modern chemical technology to form a complete set of technologies to extract essential oil, betulinol and tannin substances from white birch bark, we put more effort into the exploiture of the preparation of betulin derivatives, the improvable technology of essential oils and tannin substances in the domain of daily use chemical industry and anti-corrosion, and the technology of re-use of the extracted residues to establish the model of comprehensive use of white birch bark. Main results are as follows:1. Use uniform design to optimize the process of reflux extraction with ethanol and microwave-assisted extraction, ultrasound-assisted extraction and supercritical carbon dioxide fluid extraction of betulin. In preliminary study, we investigate the effect of the volume fraction of ethanol, extraction time on the continuous extraction of betulin. By comparing the aspects of extraction rate of betulin and the content of the extraction of betulin, taking account the factors such as the continuity of extraction, environmental protection, cost and equipment requirements at the same time, we think supercritical carbon dioxide fluid extraction method has distinguished prospects of industrial application in the extraction of betulin. The optimum conditions of supercritical carbon dioxide fluid extraction was determined, the extraction temperature, extraction pressure, extraction time were 32℃,8 Mpa,1 h, respectively. The average extraction rate and purity of betulin after a twice continuous extraction in this condition were 85.27% and 67.86%. Primary isolation and purification of betulin from the extractive of white birch bark by different extraction methods were created by ethyl acetate at liquid-solid ratio of 15:1-20:1 (mL:g). the dissolution rates of betulin can reached.or exceeded 95%, this method was more effective and meet the environmental requirements. After the re-crystallization using anhydrous ethanol as solvent, in liquid-solid ratio of 30:1 (mL:g), the purity of betulin up to 98.13%, the method suitable for large-scale separation and purification of betulin and the purity of the product meet the requirements of medical research.2. Using orthogonal design to optimize the extraction conditions of essential oil by supercritical fluid extract method from white birch bark, the result was medetermined: extraction temperature is 50℃, extraction pressure is 45 MPa, extraction time is 1 h, under this condition the yield of essential oil reached 0.54%. With water-ethanol solution as the solvent, use uniform design to optimize the process of traditional hot extraction and ultrasound-assisted extraction of tannins from white birch bark. Through the comprehensive analysis of all the factors, we think ultrasound-assisted extraction method has distinguished industrial application prospects in the extraction of tannins. Under the condition:the volume fraction of ethanol is 30%, extraction time is 2 h, extraction temperature is 35℃, ultrasonic power is 250 W, the ratio of liquid-solid is 18.5:1 (mL:g), the yield of extractive reached 12.57%, the content of tannin up to 45.68%.3. Based on the result of former research, through the comparaition of the different extraction routes, we establish the best extract route composed of the extraction of betulin by supercritical carbon dioxide method, the extraction of essential oils by supercritical carbon dioxide method and Ultrasound-assisted extraction of tannin with alcohol aqueous solution as solvent by turns. Followed by this extraction process, we can avoid interacting of essential oil, betulin and betulinic in routine extracting, craft route of white birch bark, meet the environmental requirements, the cost of unit production is low and has high efficiency.4. Use betulin as raw material, investigate the feasibility, of synthetic route of the transformation from betulin to betulinic aldehyde by oxidation catalysised with TCCA/ TEMPO system and then oxidized to betulinic acid with Ag2O/KOH system. This synthetic route can avoid the generation of 3α-isomer, has a certain value of application. Initial modification was made at C-30 position of betulin by chemical reaction, two kinds of derivatives of betulin:30-bromo-3,28-2 acetylated betulin and 30-bromo-betulin were created. We prepare water-based fragrance oils from essential oil extracted by supercritical carbon dioxide method from white birch bark and find that Tween-60 and OP-10 were better solubilizers of essential oil extract from white birch bark. New anti-rust paint was prepared by using tannin extractive extract from white birch bark as solubilizer. We find that the new anti-rust paint was superior to common anti-rust paint in the performance of chemical resistance and water resistance.5. The reuse technology of the extracted residues of essential oil, betulin and tannin from white birch bark was exploited. Both the extractions of lignin with 1,4-butanediol aqueous solution and the preparation of activated carbon by chemical activation with ZnCl2 were investigated through orthogonal design. Based on the result, the optimum extraction conditions were determined:the concentration of 1,4-butanediol aqueous solution, extraction temperature, extraction time and the liquid-solid ratio were 80% (v/v),220℃,90min,14:1 (mL:g), respectively. The yield was 36.3%. The information on the surface functional groups and structures of the carbons was provided by FT-IR spectroscopy. To the preparation of activated carbon, the influence of process variables such as the concentration of ZnCl2 solution, activation time, and activation temperature was studied. The optimum preparation conditions were also determined:the mass fraction of ZnCl2 solution is 20%, activation time is 90 min, activation temperature is 600℃, the adsorption value of iodine and methylene blue, the yield of activated carbon products prepared under this condition were 959.3 mg/g; 12.6 mL/0.1g; 54.6%, respectively.