采用聚酰胺-大孔树脂联用法对菠菜叶中总黄酮的纯化条件进行研究。以总黄酮的纯度和得率为考察指标,确定纯化菠菜叶总黄酮的最佳树脂为AB-8,其最佳纯化条件为:上样量与聚酰胺量之比为1∶2;上样量与树脂量之比为1∶8;乙醇洗脱的浓度为60%...采用聚酰胺-大孔树脂联用法对菠菜叶中总黄酮的纯化条件进行研究。以总黄酮的纯度和得率为考察指标,确定纯化菠菜叶总黄酮的最佳树脂为AB-8,其最佳纯化条件为:上样量与聚酰胺量之比为1∶2;上样量与树脂量之比为1∶8;乙醇洗脱的浓度为60%;洗脱流速为2 m L·min-1;洗脱剂的用量为2BV。总黄酮得率最高可达71.42%,纯度可达26.63%。展开更多
Pyrolysis of phenol formaldehyde resin has been investigated by Pyrolysis Gas Chromatography-Mass Spectroscopy at the different temperatures from 500℃ to 750℃. Its composition of pyrclysates has been analyzed. Sever...Pyrolysis of phenol formaldehyde resin has been investigated by Pyrolysis Gas Chromatography-Mass Spectroscopy at the different temperatures from 500℃ to 750℃. Its composition of pyrclysates has been analyzed. Several compounds, especially benzene, toluene, p-xylene could only be formed above 500-550℃. Howerver, peak intensities for some pbend derivatives were decreased at the higher temperature. During pyrolysis, for thermo-setting phenol formaldehyde resins, polymeric chain scissions take place as a successive removal of the monomer units from the polymeric chain. The chain scissions are followed by secondary reactions, which leads to a variety of compounds. Addition reactions can also take place among the double-bond compounds during pyrolysis.展开更多
文摘采用聚酰胺-大孔树脂联用法对菠菜叶中总黄酮的纯化条件进行研究。以总黄酮的纯度和得率为考察指标,确定纯化菠菜叶总黄酮的最佳树脂为AB-8,其最佳纯化条件为:上样量与聚酰胺量之比为1∶2;上样量与树脂量之比为1∶8;乙醇洗脱的浓度为60%;洗脱流速为2 m L·min-1;洗脱剂的用量为2BV。总黄酮得率最高可达71.42%,纯度可达26.63%。
文摘Pyrolysis of phenol formaldehyde resin has been investigated by Pyrolysis Gas Chromatography-Mass Spectroscopy at the different temperatures from 500℃ to 750℃. Its composition of pyrclysates has been analyzed. Several compounds, especially benzene, toluene, p-xylene could only be formed above 500-550℃. Howerver, peak intensities for some pbend derivatives were decreased at the higher temperature. During pyrolysis, for thermo-setting phenol formaldehyde resins, polymeric chain scissions take place as a successive removal of the monomer units from the polymeric chain. The chain scissions are followed by secondary reactions, which leads to a variety of compounds. Addition reactions can also take place among the double-bond compounds during pyrolysis.