乙酸乙酯混合溶剂精制塔拉单宁工艺研究

Refining of Tara Tannin with Ethyl Acetate Mixed Solvent

用乙酸乙酯萃取精制粗塔拉单宁,粗单宁、水、乙酸乙酯之比1∶1.5∶4(g∶mL∶mL),60℃下萃取30 min,其单宁得率为40.2%,单宁纯度80.4%,得率与纯度均偏低。用乙酸乙酯二次萃取其残留水相得率也偏低。对粗制的塔拉单宁用乙酸乙酯与S溶剂(体积比4∶1)混合溶剂进行精制,其最佳工艺条件是:料液比为m(粗单宁)∶V(水)∶V(混合溶剂)1∶1.5∶5(g∶mL∶mL),萃取温度60℃,萃取时间30 min。在该工艺条件下产品得率68.2%,单宁纯度86.0%,单宁提取率87.7%,得率和纯度都有提高。

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.