Two new processes for the production of insoluble sulfur (IS) were studied in thispaper.One is low temperature polymerization process of sulfur at temperature less than 350℃ and under atmospheric pressure in the pres...Two new processes for the production of insoluble sulfur (IS) were studied in thispaper.One is low temperature polymerization process of sulfur at temperature less than 350℃ and under atmospheric pressure in the presence of catalyst promotor system,aiming at producing medium grade IS.Another is mixed solvent extraction process with a small amount of additive for the production of higher grade IS.In comparison with the old high temperature polymerization and single solvent (carbon disulfide) extraction processes respectively,these two new processes are lower in first cost and operation/maintainance cost,less energy consumption and safe in operation.展开更多
考察了加速溶剂萃取(ASE)技术对海南萝芙木抗氧化活性成分的提取效果。以提取物对DPPH自由基的清除率为指标,确定水-丙酮混合溶剂为最佳溶媒,通过正交实验确定了最佳提取条件,即样品经质量分数1%的盐酸预处理30 m in后,以V(丙酮)∶V(水...考察了加速溶剂萃取(ASE)技术对海南萝芙木抗氧化活性成分的提取效果。以提取物对DPPH自由基的清除率为指标,确定水-丙酮混合溶剂为最佳溶媒,通过正交实验确定了最佳提取条件,即样品经质量分数1%的盐酸预处理30 m in后,以V(丙酮)∶V(水)=1∶1为溶媒,在125℃用加速溶剂萃取仪提取,所得提取物对DPPH自由基的清除率为89.378%,而索式提取法仅为68.45%。表明加速溶剂萃取技术可以作为萝芙木中活性成分的一种高效提取手段。展开更多
A comparative study on the fluorescence behavior of the chemical modified β-cyclodextrin appended a N,N-dimethylamino-chalcone group (DMAC-CD) and the non-modified β-CD mixed with free dimethylamino-chalcone (DMAC+C...A comparative study on the fluorescence behavior of the chemical modified β-cyclodextrin appended a N,N-dimethylamino-chalcone group (DMAC-CD) and the non-modified β-CD mixed with free dimethylamino-chalcone (DMAC+CD) in alcohol/water mixed solvents have been carried out in this work.The fluorescence data obtained——maximum peak wavelength and emission intensity——indicates that the inclusion behavior of the above-mentioned systems is obviously different in mixed alcohol/water solvents.The solvent-induced multi-component complex formation and dissociation and the effect of polarity and size of alcohol used have been also studied carefully by variation of the fluorescence spectroscopic characters.The result indicates that the self-inclusion complex of DMAC-CD has a higher stability in mixed alcohol/water solvents than that in the DMAC +β-CD system.The obtained results and the observed phenomena have been discussed in details.展开更多
文摘Two new processes for the production of insoluble sulfur (IS) were studied in thispaper.One is low temperature polymerization process of sulfur at temperature less than 350℃ and under atmospheric pressure in the presence of catalyst promotor system,aiming at producing medium grade IS.Another is mixed solvent extraction process with a small amount of additive for the production of higher grade IS.In comparison with the old high temperature polymerization and single solvent (carbon disulfide) extraction processes respectively,these two new processes are lower in first cost and operation/maintainance cost,less energy consumption and safe in operation.
文摘考察了加速溶剂萃取(ASE)技术对海南萝芙木抗氧化活性成分的提取效果。以提取物对DPPH自由基的清除率为指标,确定水-丙酮混合溶剂为最佳溶媒,通过正交实验确定了最佳提取条件,即样品经质量分数1%的盐酸预处理30 m in后,以V(丙酮)∶V(水)=1∶1为溶媒,在125℃用加速溶剂萃取仪提取,所得提取物对DPPH自由基的清除率为89.378%,而索式提取法仅为68.45%。表明加速溶剂萃取技术可以作为萝芙木中活性成分的一种高效提取手段。
文摘A comparative study on the fluorescence behavior of the chemical modified β-cyclodextrin appended a N,N-dimethylamino-chalcone group (DMAC-CD) and the non-modified β-CD mixed with free dimethylamino-chalcone (DMAC+CD) in alcohol/water mixed solvents have been carried out in this work.The fluorescence data obtained——maximum peak wavelength and emission intensity——indicates that the inclusion behavior of the above-mentioned systems is obviously different in mixed alcohol/water solvents.The solvent-induced multi-component complex formation and dissociation and the effect of polarity and size of alcohol used have been also studied carefully by variation of the fluorescence spectroscopic characters.The result indicates that the self-inclusion complex of DMAC-CD has a higher stability in mixed alcohol/water solvents than that in the DMAC +β-CD system.The obtained results and the observed phenomena have been discussed in details.
