The formation of toxic nitrogenous disinfection byproducts （N-DBPs）, such as nitrosamines, halonitromethanes and haloacetonitriles, from reactions between chlorine/chloramine and dissolved organic nitrogen in drinki...The formation of toxic nitrogenous disinfection byproducts （N-DBPs）, such as nitrosamines, halonitromethanes and haloacetonitriles, from reactions between chlorine/chloramine and dissolved organic nitrogen in drinking water has caused great concern with regarding public health. This study revealed the occurrence of 17 aliphatic amines, some of which have been confirmed to be the precursors of N-DBPs, in source water across China. A sensitive method based on benzenesulfonyl chloride derivatization and liquid-liquid extraction followed by GC-MS analysis was established for the simultaneous analysis of the selected amines in aqueous samples. In total, 37 source water samples from the capital cities of 20 provinces were collected for the survey. Among the 17 amines, 14 were detected with an average frequency of detection of 36%. The most relevant amines in terms of frequency and maximum concentrations detected were dimethylamine （100%, 24.82 μg/L）, methylamine （78%, 0.92 μg/L）, N-methylethylamine （70%, 8.84 μg/L）, propylamine （59%, 10.69 μg/L）, diethylamine （54%, 3.76μg/L）, N-methylbutylamine （35%, 3.07 μg/L）, N-ethylpropylamine （35%, 0.52μg/L）, and piperidine （32%, 2.35 μg/L）. This is the first large scale survey of the aliphatic amines occurrence in source water in the world. The wide presence of nitrosamine precursors like dimethylamine, N-methylethylamine and diethylamine, and the precursors of haloacetonitriles and halonitromethanes like methylamine and propylamine suggests that better source water management is required to ensure the safety of drinking water.展开更多
A testing method for N-nitrosamines and N-nitrosatable substances in rubber teats and soothers was modified. N-Nitrosamines are generally analyzed using either a nitrogen chemiluminescence detector (NCD) or a thermal ...A testing method for N-nitrosamines and N-nitrosatable substances in rubber teats and soothers was modified. N-Nitrosamines are generally analyzed using either a nitrogen chemiluminescence detector (NCD) or a thermal energy analyzer (TEA). However, because few testing laboratories are equipped with these devices, it is difficult to conduct these tests. Therefore, an analysis method for N-nitrosamines using the more widespread gas chromatography-mass spectrometry (GC-MS) method was improved. In addition, EN 12868 was used to prepare the test solutions because of its worldwide use and compliance with EU regulations. Using GC-MS, EN 12868 method targeting ten kinds of N-nitrosamines was modified. The determination limits of the method were 1.0 -1.5 μg/kg for N-nitrosamines and 4 -6 μg/kg for N-nitrosatable substances. Quantification was possible at 1/5 or less and 1/15 or less, respectively, of the regulation values listed in EU Directive 93/11/EEC. In terms of application, there were no problems with the selectivity of the detector. The recoveries were 58% -109% for N-nitrosamines and 59% -102% for N-nitrosatable substances. Screening and verification were possible by measuring the amount of secondary amines in the boiled solution and migration solution.展开更多
Mercurous chloride catalyzed Mannich condensation of terminal alkynes with secondary amines and aldehydes has been developed. The reaction generated β-aminoalkynes in good yields.
Ring opening of aziridine with dialkyl amine took place readily in the presence of catalytic amounts of tri-n-butylphosphane （10 mol%） in the mixture of CH3CN/H20 （10：1）, giving corresponding vicinal diamines in ...Ring opening of aziridine with dialkyl amine took place readily in the presence of catalytic amounts of tri-n-butylphosphane （10 mol%） in the mixture of CH3CN/H20 （10：1）, giving corresponding vicinal diamines in mediate to high yields （58-95%） with good regioselectivitie, while aromatic secondary amine could not react under the same conditions. Tri-n-butylphosphane exhibited different catalytic selectivity to amines from Lewis acid catalysts.展开更多
Sodium borohydride supported on alumina reduces imines to the corresponding secondary amines in high to excellent isolated yields under solvent-free conditions. Noteworthy is that highly chemoselective reactions were ...Sodium borohydride supported on alumina reduces imines to the corresponding secondary amines in high to excellent isolated yields under solvent-free conditions. Noteworthy is that highly chemoselective reactions were achieved in the presence of other functional groups such as halogen, nitro, and cyano groups.展开更多
Preparation of allenyl perfluoroalkyl sulfones from perfluoroalkyl sulfinyl chlorides and their reactions with secondary amines and water were studied. At room temperature secondary amines reacted readily with allenyl...Preparation of allenyl perfluoroalkyl sulfones from perfluoroalkyl sulfinyl chlorides and their reactions with secondary amines and water were studied. At room temperature secondary amines reacted readily with allenyl perfluoroalkyl sulfones to give the corresponding enamine adducts, which underwent rearrangement to afford conjugate enamines in refluxing toluene. Good diastereoslectivities were observed in the addition of diethylamine to 7-ethyl-7-methylallenyl perfluoroalkyl sulfones. In refluxing acetonitrile, water could also undergo the similar addition with allenyl perfluoroalkyl sulfones.展开更多
Microalgae are considered a promising feedstock for the production of food ingredients, cosmetics, pharmaceutical products and biofuels.The energy intensity of drying and cell breaking of algae and solvent recovery af...Microalgae are considered a promising feedstock for the production of food ingredients, cosmetics, pharmaceutical products and biofuels.The energy intensity of drying and cell breaking of algae and solvent recovery afterwards hindered the route of algae biorefinery. In this work the influences of freeze drying and cell breaking to the extraction efficiency of crude lipid yield and fatty acid yield were investigated. Results showed that drying and cell breaking are not necessary for N-ethyl butylamine extraction, because good yields were obtained without. Crude lipid yield and fatty acid yield using N-ethyl butylamine were comparable with Bligh & Dyer extraction, making N-ethyl butylamine a candidate for further development of an energy efficient lipid extraction technology for non-broken microalgae.展开更多
基金supported by the National Natural Science Foundation of China (No.21077118)the National Special Funding Project for Water Pollution Control and Management of China (No.2009ZX07419-001)
文摘The formation of toxic nitrogenous disinfection byproducts （N-DBPs）, such as nitrosamines, halonitromethanes and haloacetonitriles, from reactions between chlorine/chloramine and dissolved organic nitrogen in drinking water has caused great concern with regarding public health. This study revealed the occurrence of 17 aliphatic amines, some of which have been confirmed to be the precursors of N-DBPs, in source water across China. A sensitive method based on benzenesulfonyl chloride derivatization and liquid-liquid extraction followed by GC-MS analysis was established for the simultaneous analysis of the selected amines in aqueous samples. In total, 37 source water samples from the capital cities of 20 provinces were collected for the survey. Among the 17 amines, 14 were detected with an average frequency of detection of 36%. The most relevant amines in terms of frequency and maximum concentrations detected were dimethylamine （100%, 24.82 μg/L）, methylamine （78%, 0.92 μg/L）, N-methylethylamine （70%, 8.84 μg/L）, propylamine （59%, 10.69 μg/L）, diethylamine （54%, 3.76μg/L）, N-methylbutylamine （35%, 3.07 μg/L）, N-ethylpropylamine （35%, 0.52μg/L）, and piperidine （32%, 2.35 μg/L）. This is the first large scale survey of the aliphatic amines occurrence in source water in the world. The wide presence of nitrosamine precursors like dimethylamine, N-methylethylamine and diethylamine, and the precursors of haloacetonitriles and halonitromethanes like methylamine and propylamine suggests that better source water management is required to ensure the safety of drinking water.
文摘A testing method for N-nitrosamines and N-nitrosatable substances in rubber teats and soothers was modified. N-Nitrosamines are generally analyzed using either a nitrogen chemiluminescence detector (NCD) or a thermal energy analyzer (TEA). However, because few testing laboratories are equipped with these devices, it is difficult to conduct these tests. Therefore, an analysis method for N-nitrosamines using the more widespread gas chromatography-mass spectrometry (GC-MS) method was improved. In addition, EN 12868 was used to prepare the test solutions because of its worldwide use and compliance with EU regulations. Using GC-MS, EN 12868 method targeting ten kinds of N-nitrosamines was modified. The determination limits of the method were 1.0 -1.5 μg/kg for N-nitrosamines and 4 -6 μg/kg for N-nitrosatable substances. Quantification was possible at 1/5 or less and 1/15 or less, respectively, of the regulation values listed in EU Directive 93/11/EEC. In terms of application, there were no problems with the selectivity of the detector. The recoveries were 58% -109% for N-nitrosamines and 59% -102% for N-nitrosatable substances. Screening and verification were possible by measuring the amount of secondary amines in the boiled solution and migration solution.
基金Project supported by the National Natural Science Foundation of China （No. 20372024）, the Excellent Scientist Foundation of Anhui Province （No.04046080）, the Natural Science Foundation of the Education Department of Anhui Province （No. 2002kj254zd）, the Scientific Research Foundation for the Returned 0verseas Chinese Scholars, the Ministry of Education of China （No. 2002247）, the Excellent Young Teacher Program of the Ministry of Education of China （No. 2024） and the Key Project of Science and Technology of the Ministry of Education of China （No. 0204069）.
文摘Mercurous chloride catalyzed Mannich condensation of terminal alkynes with secondary amines and aldehydes has been developed. The reaction generated β-aminoalkynes in good yields.
基金This research was supported by the NSFC(20572015,20672028)Programfor Young Excellent Talents in Henan Universities and Foundation of Henan University(07YB2R006)Programof Henan University(SBGJ090506)
基金supported by the National Natural Science Foundation of China(No.20872031)
文摘Ring opening of aziridine with dialkyl amine took place readily in the presence of catalytic amounts of tri-n-butylphosphane （10 mol%） in the mixture of CH3CN/H20 （10：1）, giving corresponding vicinal diamines in mediate to high yields （58-95%） with good regioselectivitie, while aromatic secondary amine could not react under the same conditions. Tri-n-butylphosphane exhibited different catalytic selectivity to amines from Lewis acid catalysts.
基金Chamran University Research Council are gratefully acknowledged.
文摘Sodium borohydride supported on alumina reduces imines to the corresponding secondary amines in high to excellent isolated yields under solvent-free conditions. Noteworthy is that highly chemoselective reactions were achieved in the presence of other functional groups such as halogen, nitro, and cyano groups.
基金Project supported by the National Natural Science Foundation of China（No.20572124）.
文摘Preparation of allenyl perfluoroalkyl sulfones from perfluoroalkyl sulfinyl chlorides and their reactions with secondary amines and water were studied. At room temperature secondary amines reacted readily with allenyl perfluoroalkyl sulfones to give the corresponding enamine adducts, which underwent rearrangement to afford conjugate enamines in refluxing toluene. Good diastereoslectivities were observed in the addition of diethylamine to 7-ethyl-7-methylallenyl perfluoroalkyl sulfones. In refluxing acetonitrile, water could also undergo the similar addition with allenyl perfluoroalkyl sulfones.
基金performed within the AlgaePARC Biorefinery program with financial support from the Netherlands'Ministry of Economic Affairs in the framework of the TKI BioBased Economy under contract nr.TKIBE01009
文摘Microalgae are considered a promising feedstock for the production of food ingredients, cosmetics, pharmaceutical products and biofuels.The energy intensity of drying and cell breaking of algae and solvent recovery afterwards hindered the route of algae biorefinery. In this work the influences of freeze drying and cell breaking to the extraction efficiency of crude lipid yield and fatty acid yield were investigated. Results showed that drying and cell breaking are not necessary for N-ethyl butylamine extraction, because good yields were obtained without. Crude lipid yield and fatty acid yield using N-ethyl butylamine were comparable with Bligh & Dyer extraction, making N-ethyl butylamine a candidate for further development of an energy efficient lipid extraction technology for non-broken microalgae.
