In this study,the structural characters,antioxidant activities and bile acid-binding ability of sea buckthorn polysaccharides(HRPs)obtained by the commonly used hot water(HRP-W),pressurized hot water(HRP-H),ultrasonic...In this study,the structural characters,antioxidant activities and bile acid-binding ability of sea buckthorn polysaccharides(HRPs)obtained by the commonly used hot water(HRP-W),pressurized hot water(HRP-H),ultrasonic(HRP-U),acid(HRP-C)and alkali(HRP-A)assisted extraction methods were investigated.The results demonstrated that extraction methods had significant effects on extraction yield,monosaccharide composition,molecular weight,particle size,triple-helical structure,and surface morphology of HRPs except for the major linkage bands.Thermogravimetric analysis showed that HRP-U with filamentous reticular microstructure exhibited better thermal stability.The HRP-A with the lowest molecular weight and highest arabinose content possessed the best antioxidant activities.Moreover,the rheological analysis indicated that HRPs with higher galacturonic acid content and molecular weight showed higher viscosity and stronger crosslinking network(HRP-C,HRP-W and HRP-U),which exhibited stronger bile acid binding capacity.The present findings provide scientific evidence in the preparation technology of sea buckthorn polysaccharides with good antioxidant and bile acid binding capacity which are related to the structure affected by the extraction methods.展开更多
Carbon dioxide fixation technique was developed as an alternative dechlorination method of chlorobenzenes. Electrolysis of chlorobenzene was carried out in a one-compartment cell fitted with an aluminium anode and a p...Carbon dioxide fixation technique was developed as an alternative dechlorination method of chlorobenzenes. Electrolysis of chlorobenzene was carried out in a one-compartment cell fitted with an aluminium anode and a platinum cathode. Electrolysis in N, N-dimethylformamide （DMF） solution containing 0.1 M of tetrapropylammonium bromide （TPAB） at 0 ℃, 100 ml/min of CO2 flow rate and 120 mA/cm^2 of current density was found to be the optimum conditions of this electrocarboxylation, which gave 72% yield of benzoic acid from chlorobenzene. These conditions were then applied to 1,2-dichlorobenzene and 1,3-dichlorobenzene in order to convert them to their corrcsponding benzoic acids.展开更多
Liquid-phase acrylic acid hydration over solid-phase catalysts is a key reaction for the industrial productionof 3-hydroxypropionic acid. However, the relevant literature primarily focuses on the experimental aspects ...Liquid-phase acrylic acid hydration over solid-phase catalysts is a key reaction for the industrial productionof 3-hydroxypropionic acid. However, the relevant literature primarily focuses on the experimental aspects of catalystscreening and exploring reaction conditions, with few accurate descriptions of the reaction kinetics and determination ofthe reaction mechanism. Here, we combined kinetics experiments and theoretical calculations to elucidate the kinetics andmechanism of acrylic acid hydration on a resin catalyst. The pseudo-homogeneous model, and Langmuir-Hinshelwood-Haugen-Watson and Elie-Riedel (ER) heterogeneous models were used to explain the experimental kinetics data. TheER model can explain the experimental data very well, suggesting strong adsorption of acrylic acid on the surface of theresin catalyst. Furthermore, density functional theory calculations show that the hydration follows a stepwise, rather than aconcerted, reaction pathway. The present study provides theoretical insights into the reaction mechanism and kinetics, fillingthe gap in our understanding of the reaction on a fundamental level.展开更多
建立高效液相色谱检测桦褐孔菌粗提物中原儿茶酸、原儿茶醛和紫萁酮3种化合物含量的方法,对比评价超声辅助提取法、回流提取法、微波辅助提取法、酶解提取法4种不同提取方法对桦褐孔菌粗提物中活性成分含量的影响。结果表明,该检测方法...建立高效液相色谱检测桦褐孔菌粗提物中原儿茶酸、原儿茶醛和紫萁酮3种化合物含量的方法,对比评价超声辅助提取法、回流提取法、微波辅助提取法、酶解提取法4种不同提取方法对桦褐孔菌粗提物中活性成分含量的影响。结果表明,该检测方法精密度较高,3种化合物的精密度的相对标准偏差(relative standard deviation,RSD)分别为0.14%、0.06%、0.20%;重复性RSD分别为1.67%、1.98%、2.22%;在24 h内稳定性较好,其RSD分别为0.20%、0.61%、0.25%。对比不同提取方法对3种化合物的影响,发现采用超声辅助提取法得到的目标化合物产量较高,适用于桦褐孔菌中主要活性成分的提取。该研究建立的HPLC法检测桦褐孔菌粗提物中原儿茶酸、原儿茶醛和紫萁酮含量的结果准确。展开更多
基金The Guangdong Basic and Applied Basic Research Foundation(2022A1515010730)National Natural Science Foundation of China(32001647)+2 种基金National Natural Science Foundation of China(31972022)Financial and moral assistance supported by the Guangdong Basic and Applied Basic Research Foundation(2019A1515011996)111 Project(B17018)。
文摘In this study,the structural characters,antioxidant activities and bile acid-binding ability of sea buckthorn polysaccharides(HRPs)obtained by the commonly used hot water(HRP-W),pressurized hot water(HRP-H),ultrasonic(HRP-U),acid(HRP-C)and alkali(HRP-A)assisted extraction methods were investigated.The results demonstrated that extraction methods had significant effects on extraction yield,monosaccharide composition,molecular weight,particle size,triple-helical structure,and surface morphology of HRPs except for the major linkage bands.Thermogravimetric analysis showed that HRP-U with filamentous reticular microstructure exhibited better thermal stability.The HRP-A with the lowest molecular weight and highest arabinose content possessed the best antioxidant activities.Moreover,the rheological analysis indicated that HRPs with higher galacturonic acid content and molecular weight showed higher viscosity and stronger crosslinking network(HRP-C,HRP-W and HRP-U),which exhibited stronger bile acid binding capacity.The present findings provide scientific evidence in the preparation technology of sea buckthorn polysaccharides with good antioxidant and bile acid binding capacity which are related to the structure affected by the extraction methods.
文摘Carbon dioxide fixation technique was developed as an alternative dechlorination method of chlorobenzenes. Electrolysis of chlorobenzene was carried out in a one-compartment cell fitted with an aluminium anode and a platinum cathode. Electrolysis in N, N-dimethylformamide （DMF） solution containing 0.1 M of tetrapropylammonium bromide （TPAB） at 0 ℃, 100 ml/min of CO2 flow rate and 120 mA/cm^2 of current density was found to be the optimum conditions of this electrocarboxylation, which gave 72% yield of benzoic acid from chlorobenzene. These conditions were then applied to 1,2-dichlorobenzene and 1,3-dichlorobenzene in order to convert them to their corrcsponding benzoic acids.
文摘Liquid-phase acrylic acid hydration over solid-phase catalysts is a key reaction for the industrial productionof 3-hydroxypropionic acid. However, the relevant literature primarily focuses on the experimental aspects of catalystscreening and exploring reaction conditions, with few accurate descriptions of the reaction kinetics and determination ofthe reaction mechanism. Here, we combined kinetics experiments and theoretical calculations to elucidate the kinetics andmechanism of acrylic acid hydration on a resin catalyst. The pseudo-homogeneous model, and Langmuir-Hinshelwood-Haugen-Watson and Elie-Riedel (ER) heterogeneous models were used to explain the experimental kinetics data. TheER model can explain the experimental data very well, suggesting strong adsorption of acrylic acid on the surface of theresin catalyst. Furthermore, density functional theory calculations show that the hydration follows a stepwise, rather than aconcerted, reaction pathway. The present study provides theoretical insights into the reaction mechanism and kinetics, fillingthe gap in our understanding of the reaction on a fundamental level.
文摘建立高效液相色谱检测桦褐孔菌粗提物中原儿茶酸、原儿茶醛和紫萁酮3种化合物含量的方法,对比评价超声辅助提取法、回流提取法、微波辅助提取法、酶解提取法4种不同提取方法对桦褐孔菌粗提物中活性成分含量的影响。结果表明,该检测方法精密度较高,3种化合物的精密度的相对标准偏差(relative standard deviation,RSD)分别为0.14%、0.06%、0.20%;重复性RSD分别为1.67%、1.98%、2.22%;在24 h内稳定性较好,其RSD分别为0.20%、0.61%、0.25%。对比不同提取方法对3种化合物的影响,发现采用超声辅助提取法得到的目标化合物产量较高,适用于桦褐孔菌中主要活性成分的提取。该研究建立的HPLC法检测桦褐孔菌粗提物中原儿茶酸、原儿茶醛和紫萁酮含量的结果准确。
