Using Tara pod powder as raw material and methanol as extracting solvent,the effects of different solvents on extraction of tara tannin were studied.The results show that the optimum conditions were extraction temperature 60 ℃,extraction time 40 min,extraction three times and each for 1 h.Tara powder to solvent ratio were 4.5 ∶ 1,4 ∶ 1,4 ∶ 1(mL ∶ g),respectively.The yield of product was 67.2 % to 68.4%,relative error was 1.77%.The tannin purity was 66.0% to 67.5%,relative error was 2.25%.The yield of tannin was 91.5%.

Germanium was widely used in the semiconductor materials,metal materials,infrared optics,optical communications,biomedicals,etc.In this study chestnut shell tannin extract that was prepared from usually abandoned chestnut shell as raw material,was used as a complexing precipitant of geranium ion.The effects of reaction time,reaction temperature,the amount of chestnut shell tannin extract,pH value,ZnSO4 concentration during complexing precipitation were tested respectively.According to single factor and orthogonal experiment results,the optium experimental conditions were as follows:pH value 2.5,the amount of tannin extract to(36 times of germanium),ZnSO4 content of 110 g/L.Under these conditions,the recovery of germanium was up to 99.0%.

Using tara powder from Peru as raw material,rate of Ge precipitation from industrial mining liquor contaning zinc sulfate and germanium ion as index,the effects of extraction,refining and post-processing of tara extracts on the rate of Ge precipitation were studied.The results showed that using organic solvents(methanol,ethanol,ethyl acetate) extraction instead of water extraction,rate of Ge precipitation was more than 98%.Degumming of the extract with activated carbon and salting washing as well as through complexation by adding 1 % sodium chloride ammonium and 1% nitrilotriacetic acid effectively reduced non-tannin content in the product and enhanced the rate of Ge precipitation.When tara powder and gall flower of mixed in 8 ∶ 2 as raw material,followed by complexation of the extract,the rate of Ge precipitation reached 99.05%.The cost of the product was reduced,as well.

Crude tara tannin was extracted by water and ethyl acetate at 60 ℃ for 30 min.The ratio of crude tannin-water-ethyl acetate was 1 ∶ 1.5 ∶ 4(g ∶ mL ∶ mL).The yield of product was 40.2 % and the purity of tannin was 80.4 %.Both yield and purity are low.The yield was still low when ethyl acetate was used to extract the recidual water phase.Refining tara tannin with mixed solvent of ethyl acetate and S-solvent(4 ∶ 1) was studied.The optimum conditions are: solid to liquid ratio of m(crude tara tannin) ∶ V(water) ∶ V(mixed solvent)1 ∶ 1.5 ∶ 5(g ∶ mL ∶ mL),extraction temperature 60 ℃,extraction time 30 min.Under this condition,the yield of product was 67.1 %-69.0 %,the purity of tannin was 85.3 %-86.5 %,the extraction rate of tannin was 87.2 %-88.6 %.The yield and purity has been improved.

Purification of chestnut shell tannin from generally abandoned chestnut shell was studied.The effect of adsorbent,pre-column concentration,eluent,pH value of distilled water and flow rate on tannin yield was tested respectively.According to single factor and orthogonal experiment results,the optium experimental conditions were as follows: macroporous resin D301 as adsorbent,acetone as eluent,pre-column concentration 9%,pH value 7.0 of distilled water,flow rate 0.4 L/h.Finally,the best process condition was verified by stability test.Under these conditions,the yield of chestnut shell tannin was up to 82%,and tannin mass fraction was higher than 62%.

Major production processes of pyrogallol were introduced.Pyrogallol products can be produced from processing of forestry resource,and chemical synthesis.Technologies of various preparing processes as well as comparison of these processes are described.In addition,the applications of pyrogallol in the fields of analysis,synthesis,medicine,feed and pesticides,etc.,are introduced,respectively.

In this study, polyphenol was prepared from chestnut shell. Ethanol solution was used as the extraction solvent, and then membrane separation technology was applied to increase its purity. Finally, the polyphenol of chestnut shell complexing Ge was tested, and it turns out that we have a favorable outcome. Specific studies are as follows：

[Objective] To optimize the condition of purified chestnut shell tannin.[Method] By dint of polysulfone membrane,the effect of the molecular weight cutoff,trans-membrane pressure,flow velocity,and temperature on membrane property and product quality were researched with the orthogonal experimental method for the optimal design of experimental factor.[Result] The experimental results indicated that under the conditions of 10 000 molecular weight cutoff,0.2 MPa of tans-membrane pressure,2.0 m/s of flow velocity,and 40 ℃of temperature,the chestnut shell tannin with turbidity≤0.8NTU,and purity≥64% was obtained.[Conclusion] The method was easy to operate,efficient,energy-saving and environmental protective so as to provide technological reference for the development of production craft of tannin in Chestnut.

[Objective]The condition of the polyphenol extracted from chestnut shell was preferred through the experiment.[Method] The effect of extraction solvent and its concentration,the extraction time and temperature,the ratio of solid to liquid and other factors on the extraction of polyphenol from chestnut shell as raw material was researched with the orthogonal experimental method for the optimal design of experimental factor.[Result]The best extracting condition of the polyphenol from chestnut shell was that the concentration of ethanol solution was 40%;the ratio of solid to liquid,1∶20;and the temperature of water-bathing,80 ℃ for 120 minutes' extraction,under which condition,the extraction amount of tannins was up to 71.53% and the content of tannin was 49.83%.[Conclusion] The extraction of the polyphenol from chestnut shell was feasible and it was really available for raw material,which had important economic and social significance in its extensive use.

After discoloration, crude 2,3,4,4′-tetrahydroxybenzophenone, was adsorbed and separated by chromatographic column and micro-porous membrane, the impacts of membrane aperture and operating pressure on separation effect were studied. Furthermore, the adsorption-desorption regenerating test of the used column was done, the impacts of temperature and the amount of eluate on elution results were investigated. The results showed that the optimum separation conditions were: membrane aperture 0.2μm, pressure 0.06MPa, working the column in series with micro-porous membrane. Under these conditions the indices of the product were as follows: mass fraction ≥99.5%, impurities of Ca2+, Fe3+, Na+≤200μg/L. Using 300mL 50% ethanol as eluant for the regeneration of the used column, the desired results were obtained.

Pharmaceutical tannic acid was prepared from industrial tannic acid through methanol extraction and chromatography adsorption.The optimum conditions were determined as follows:ratio of industrial tannic acid to methanol 1∶5(g∶mL),temperature of actived carbon-adsorption column 60℃,and the flow rate 25mL/min.The content of tannic acid of product was over 93%.The other items had reached the requirements of pharmaceutical tannic acid.