To investigate the relationships between structures and toxicities of 13 quaternary ammonium compounds (QACs) to Chlorella pyrenoidosa, 2D- and 3D-QSAR models were built. The 2D-QSAR model included two parameters: ...To investigate the relationships between structures and toxicities of 13 quaternary ammonium compounds (QACs) to Chlorella pyrenoidosa, 2D- and 3D-QSAR models were built. The 2D-QSAR model included two parameters: averaged polarizability (a) and total connectivity (Tcon). Furthermore, 3D-QSAR models were proposed by using comparative molecular field analysis (CoMFA) and molecular similarity index analysis (CoMSIA). All these models were robust and predictive. To our interest, 3D-QSAR model suggested that the hydrophobieity of substituents was the dominating factor for the toxicities, electrostatic effect was the secondly important, and steric field gave the least contribution. Comparatively, the predictive ability of 3D-QSAR model is slightly more advantageous than that of 2D-QSAR. They can be used complementally in the toxicity description of this kind of compounds.展开更多
Quaternary ammonium compound are a class of broad-spectrum,high-efficiency and low-toxicity bactericide,which are widely used in daily life and industrial sterilization.Herein,the current state of domestic quaternary ...Quaternary ammonium compound are a class of broad-spectrum,high-efficiency and low-toxicity bactericide,which are widely used in daily life and industrial sterilization.Herein,the current state of domestic quaternary ammonium disinfectant products was summarized,as well as those new products developed and studied,and the development trend was also predicted.展开更多
A series of bis-quaternary ammonium compounds(bis-QACs) N,N'-hevamethylenebis(1-alkyl-4-carbamoyl pyridinium bromide)(4BCAP-6,n)(alkyl chain length,n=8,10,12,14,16 and 18) were synthesized and characterized.T...A series of bis-quaternary ammonium compounds(bis-QACs) N,N'-hevamethylenebis(1-alkyl-4-carbamoyl pyridinium bromide)(4BCAP-6,n)(alkyl chain length,n=8,10,12,14,16 and 18) were synthesized and characterized.Their surface tensions,critical micelle concentrations(CMC),and antimicrobial activities were evaluated.4BCAP-6,10 exhibited the strongest antimicrobial activities except for that against Proteus vulgari.The activities of 4BCAP-6.n against Escherichia coli zk126 were not significantly influenced by temperature.pH and initial bacteria concentration.These results indicate that bis-QACs exhibit high antimicrobial activity regardless of the environmental conditions.展开更多
This paper reports a new method for oxidizing the α-methyl or α-methylene groups in carbonyl compounds into 1,2-dicarbonyl compounds by ammonium chlorochromate(ACC).
Copolymers of quaternary ammonium monomer(QAM) and hydrophilic co-monomer were successfully synthesized by free radical polymerization. It was discovered that the hydrophilic co-monomers with poor antibac- terial ac...Copolymers of quaternary ammonium monomer(QAM) and hydrophilic co-monomer were successfully synthesized by free radical polymerization. It was discovered that the hydrophilic co-monomers with poor antibac- terial activity significantly enhanced the activity of QAM substituted with a long alkyl chain[i.e., N,N-dimethyl-N-dodecyl methacrylate ammonium bromide(DMAEMA-DB)]. When a suitable molar ratio of DMAEMA-DB to co-monomer was selected, the activity of the copolymers was up to 123 times that of the homopolymer of DMAEMA-DB against S. aureus, and 282 times that of it against E. colt. But unlike DMAEMA-DB, the co-monomers might weaken the activity of QAM substituted with a short alkyl chain[i.e., N,N-dimethyl-N-butyl methacrylate ammonium bromide(DMAEMA-BB)]. Moreover, it was found that copolymers of DMAEMA-DB were much more biocidal than those of DMAEMA-BB. Therefore, it could be speculated that the long alkyl chain plays an important role in the antibacterial activity, and that the hydrophilie co-monomers are beneficial to polymeric guaternary ammonium compounds(PQACs) to exert the positive effect of the long alkyl chain to the greatest degree.展开更多
Quaternary ammonium compounds(QACs)are commonly used in a variety of consumer and commercial products,typically as a component of disinfectants.During the COVID-19 pandemic,QACs became one of the primary agents utiliz...Quaternary ammonium compounds(QACs)are commonly used in a variety of consumer and commercial products,typically as a component of disinfectants.During the COVID-19 pandemic,QACs became one of the primary agents utilized to inactivate the SARS CoV-2 virus on surfaces.However,the ecotoxicological effects of QACs upon aquatic organisms have not been fully assessed.In this study,we examined the effects of a widely used QAC(benzalkonium chloride-C_(14),BAC-14)on two toxigenic Microcystis strains and one non-toxigenic freshwater Microcystis strain and carried out an analysis focused on primary,adaptive and compensatory stress responses at apical(growth and photosynthesis)and metabolic levels.This analysis revealed that the two toxic Microcystis strains were more tolerant than the non-toxic strain,with 96 hr-EC_(50)values of 0.70,0.76,and 0.38 mg/L BAC-14 for toxigenic M.aeruginosa FACHB-905,toxigenic M.aeruginosa FACHB-469,and non-toxigenic M.wesenbergii FACHB-908,respectively.The photosynthetic activities of the Microcystis,assessed via F_(v)/F_(m) values,were significantly suppressed under 0.4 mg/L BAC-14.Furthermore,this analysis revealed that BAC-14 altered 14,12,and 8 metabolic pathways in M.aeruginosa FACHB-905,M.aeruginosa FACHB-469,and M.wesenbergii FACHB-908,respectively.It is noteworthy that BAC-14 enhanced the level of extracellular microcystin production in the toxigenic Microcystis strains,although cell growth was not significantly affected.Collectively,these data show that BAC-14 disrupted the physiological and metabolic status of Microcystis cells and stimulated the production and release of microcystin,which could result in damage to aquatic systems.展开更多
We investigated the effect of small amounts of ammonium sulfate (NH4)2SO4 on compound fertilizer granulation. We examined the following raw materials: humic acid, ammonium chloride, urea, potassium chloride, and mo...We investigated the effect of small amounts of ammonium sulfate (NH4)2SO4 on compound fertilizer granulation. We examined the following raw materials: humic acid, ammonium chloride, urea, potassium chloride, and monoammonium phosphate. The mass ratio of organic matter, nitrogen, phosphorus, and potassium was typically 22:17:7:2. In the absence of (NH4)2SO4, the granulation rate of the compound fertilizer was low, and increased significantly following the addition of 1–2% (NH4)2SO4. We suggested the following physical and chemical processes as potential mechanisms: (NH4)2SO4 promoted the conversion of yellow flue gas desulfurization gypsum into gypsum whiskers; (NH4)2SO4 interacted with humic acid and urea to generate a new complex; urea sulfate was formed under acidic conditions. The combined effect of the above physical and chemical processes was an increase both in the rate of interactions between the materials and in system viscosity, which has the end result of increasing the granulation rate.展开更多
Pathogenic bacterial contaminations in water cause serious or even lethal threats.Strategies that effectively kill bacteria without causing environmental contamination are urgently needed in a wide range of applicatio...Pathogenic bacterial contaminations in water cause serious or even lethal threats.Strategies that effectively kill bacteria without causing environmental contamination are urgently needed in a wide range of applications.We prepared recyclable antimicrobial magnetic nanoparticles,Fe304@P(St-coAcQAC),through surfactant-free seeded emulsion polymerization involving a polymerizable,hydrophobic quaternary ammonium compound(QAC).Fe304 particles were first synthesized by a solvothermal reaction,followed by functionalization with a methacrylic silane(MPS),and then copolymerized with a QAC-containing acrylic monomer(AcQAC),leading to Fe304@P(St-co-AcQAC) nanoparticles.As confirmed by antibacterial assays,these Fe304@P(St-co-AcQAC) nanoparticles exhibited strong antimicrobial action against both Gram-positive Staphylococcus epidermidis and Gram-negative Escherichia coli,without leaching out any bactericidal agent.An additional benefit of antimicrobial magnetic particles is that they can be easily recycled while maintaining excellent antimicrobial efficacy.展开更多
基金supported by the Environmental Science and Technology Innovation Team project of Jiangsu provincethe Natural Science Foundation of the Jiangsu Higher Education Institutions of China(No.13KJB150012)
文摘To investigate the relationships between structures and toxicities of 13 quaternary ammonium compounds (QACs) to Chlorella pyrenoidosa, 2D- and 3D-QSAR models were built. The 2D-QSAR model included two parameters: averaged polarizability (a) and total connectivity (Tcon). Furthermore, 3D-QSAR models were proposed by using comparative molecular field analysis (CoMFA) and molecular similarity index analysis (CoMSIA). All these models were robust and predictive. To our interest, 3D-QSAR model suggested that the hydrophobieity of substituents was the dominating factor for the toxicities, electrostatic effect was the secondly important, and steric field gave the least contribution. Comparatively, the predictive ability of 3D-QSAR model is slightly more advantageous than that of 2D-QSAR. They can be used complementally in the toxicity description of this kind of compounds.
文摘Quaternary ammonium compound are a class of broad-spectrum,high-efficiency and low-toxicity bactericide,which are widely used in daily life and industrial sterilization.Herein,the current state of domestic quaternary ammonium disinfectant products was summarized,as well as those new products developed and studied,and the development trend was also predicted.
基金supported by the National Natural Science Foundation of China(No.20972120)Doctor Fund of Henan University of Technology(No.150392)
文摘A series of bis-quaternary ammonium compounds(bis-QACs) N,N'-hevamethylenebis(1-alkyl-4-carbamoyl pyridinium bromide)(4BCAP-6,n)(alkyl chain length,n=8,10,12,14,16 and 18) were synthesized and characterized.Their surface tensions,critical micelle concentrations(CMC),and antimicrobial activities were evaluated.4BCAP-6,10 exhibited the strongest antimicrobial activities except for that against Proteus vulgari.The activities of 4BCAP-6.n against Escherichia coli zk126 were not significantly influenced by temperature.pH and initial bacteria concentration.These results indicate that bis-QACs exhibit high antimicrobial activity regardless of the environmental conditions.
基金The Project Supported by National Science Foundation of China.
文摘This paper reports a new method for oxidizing the α-methyl or α-methylene groups in carbonyl compounds into 1,2-dicarbonyl compounds by ammonium chlorochromate(ACC).
基金Supported by the National Natural Science Foundation of China(No.50673101), the Scientific Foundation of Guangdong Province of China(Nos.0711020600015, 2004A30404001), the Natural Science Foundation of Guangxi Zhuang Autonomous Region of China(Nos.2013GXNSFBA019040, 2013GXNSFBA019036), the Projcet of Department of Education of Guangxi Zhuang Autonomous Region, China(No.2013YB171) and the Foundation of Guangxi University of Science and Technology, China.
文摘Copolymers of quaternary ammonium monomer(QAM) and hydrophilic co-monomer were successfully synthesized by free radical polymerization. It was discovered that the hydrophilic co-monomers with poor antibac- terial activity significantly enhanced the activity of QAM substituted with a long alkyl chain[i.e., N,N-dimethyl-N-dodecyl methacrylate ammonium bromide(DMAEMA-DB)]. When a suitable molar ratio of DMAEMA-DB to co-monomer was selected, the activity of the copolymers was up to 123 times that of the homopolymer of DMAEMA-DB against S. aureus, and 282 times that of it against E. colt. But unlike DMAEMA-DB, the co-monomers might weaken the activity of QAM substituted with a short alkyl chain[i.e., N,N-dimethyl-N-butyl methacrylate ammonium bromide(DMAEMA-BB)]. Moreover, it was found that copolymers of DMAEMA-DB were much more biocidal than those of DMAEMA-BB. Therefore, it could be speculated that the long alkyl chain plays an important role in the antibacterial activity, and that the hydrophilie co-monomers are beneficial to polymeric guaternary ammonium compounds(PQACs) to exert the positive effect of the long alkyl chain to the greatest degree.
基金supported by the National Key Research and Development Program of China (Nos.2018YFD0900701 and 2019YFD0900604)the National Natural Science Foundation of China (Nos.42107150 and 32061143029)。
文摘Quaternary ammonium compounds(QACs)are commonly used in a variety of consumer and commercial products,typically as a component of disinfectants.During the COVID-19 pandemic,QACs became one of the primary agents utilized to inactivate the SARS CoV-2 virus on surfaces.However,the ecotoxicological effects of QACs upon aquatic organisms have not been fully assessed.In this study,we examined the effects of a widely used QAC(benzalkonium chloride-C_(14),BAC-14)on two toxigenic Microcystis strains and one non-toxigenic freshwater Microcystis strain and carried out an analysis focused on primary,adaptive and compensatory stress responses at apical(growth and photosynthesis)and metabolic levels.This analysis revealed that the two toxic Microcystis strains were more tolerant than the non-toxic strain,with 96 hr-EC_(50)values of 0.70,0.76,and 0.38 mg/L BAC-14 for toxigenic M.aeruginosa FACHB-905,toxigenic M.aeruginosa FACHB-469,and non-toxigenic M.wesenbergii FACHB-908,respectively.The photosynthetic activities of the Microcystis,assessed via F_(v)/F_(m) values,were significantly suppressed under 0.4 mg/L BAC-14.Furthermore,this analysis revealed that BAC-14 altered 14,12,and 8 metabolic pathways in M.aeruginosa FACHB-905,M.aeruginosa FACHB-469,and M.wesenbergii FACHB-908,respectively.It is noteworthy that BAC-14 enhanced the level of extracellular microcystin production in the toxigenic Microcystis strains,although cell growth was not significantly affected.Collectively,these data show that BAC-14 disrupted the physiological and metabolic status of Microcystis cells and stimulated the production and release of microcystin,which could result in damage to aquatic systems.
基金This work was supported by The Natural Science Foundation of Shanxi Province (Grant No. 2012011009-3).
文摘We investigated the effect of small amounts of ammonium sulfate (NH4)2SO4 on compound fertilizer granulation. We examined the following raw materials: humic acid, ammonium chloride, urea, potassium chloride, and monoammonium phosphate. The mass ratio of organic matter, nitrogen, phosphorus, and potassium was typically 22:17:7:2. In the absence of (NH4)2SO4, the granulation rate of the compound fertilizer was low, and increased significantly following the addition of 1–2% (NH4)2SO4. We suggested the following physical and chemical processes as potential mechanisms: (NH4)2SO4 promoted the conversion of yellow flue gas desulfurization gypsum into gypsum whiskers; (NH4)2SO4 interacted with humic acid and urea to generate a new complex; urea sulfate was formed under acidic conditions. The combined effect of the above physical and chemical processes was an increase both in the rate of interactions between the materials and in system viscosity, which has the end result of increasing the granulation rate.
基金the Distinguished Chair in Materials Science Endowment Fund at Georgia Southern University for the partial financial support of this research
文摘Pathogenic bacterial contaminations in water cause serious or even lethal threats.Strategies that effectively kill bacteria without causing environmental contamination are urgently needed in a wide range of applications.We prepared recyclable antimicrobial magnetic nanoparticles,Fe304@P(St-coAcQAC),through surfactant-free seeded emulsion polymerization involving a polymerizable,hydrophobic quaternary ammonium compound(QAC).Fe304 particles were first synthesized by a solvothermal reaction,followed by functionalization with a methacrylic silane(MPS),and then copolymerized with a QAC-containing acrylic monomer(AcQAC),leading to Fe304@P(St-co-AcQAC) nanoparticles.As confirmed by antibacterial assays,these Fe304@P(St-co-AcQAC) nanoparticles exhibited strong antimicrobial action against both Gram-positive Staphylococcus epidermidis and Gram-negative Escherichia coli,without leaching out any bactericidal agent.An additional benefit of antimicrobial magnetic particles is that they can be easily recycled while maintaining excellent antimicrobial efficacy.