Perfluoroalkyl acid analogs(PFAAs)are a class of chemically stable environmentally persistent organic pollutants(POPs)that are difficult to degrade and have a strong capacity to accumulate in the human body.PFAAs have...Perfluoroalkyl acid analogs(PFAAs)are a class of chemically stable environmentally persistent organic pollutants(POPs)that are difficult to degrade and have a strong capacity to accumulate in the human body.PFAAs have been found to be biotoxic to humans and have been detected in various environmental media,especially in the cryosphere at trace concentrations.The cryosphere,sensitively responds to climate change,plays a crucial role in the global water,carbon and energy cycles.However,researches on cryosphere PFAAs especially in Tibetan Plateau(TP)is limited.Therefore,we summarize the physicochemical properties,physiological toxicity,spatiotemporal distribution,sources,diffusion and migration pathways,as well as analysis and removal methods of PFAAs in the cryosphere regions.The results show that PFAAs pollutants are mainly produced and distributed in the more economically developed countries in Europe and the United States,as well as in East Asia,and PFAAs can be transported by atmospheric circulation and water cycle to remote regions including cryosphere regions.The current detection methods for PFAAs in cryosphere need to be further refined for increased accuracy and convenience.There is also a need to develop more effective removal methods that will reduce the environmental and human threats posed by these PFAAs.Finally,we propose key scientific questions for future research in cryosphere including PFAAs redistribution influenced by cryosphere changes,human activities,and the interaction of other spheres.展开更多
Intraocular lenses can be manufactured from a wide variety of polymers, but due to the lost cost associated with the use of Poly (methyl methacrylate) (PMMA), it is still the preferred material used in the developing ...Intraocular lenses can be manufactured from a wide variety of polymers, but due to the lost cost associated with the use of Poly (methyl methacrylate) (PMMA), it is still the preferred material used in the developing countries. However, a major drawback to its use is the build-up of calcium containing deposits that are formed on the intraocular lens over a period of time. In an attempt to hinder this deposition, surface modification of medical grade PMMA has been carried out using perfluoroalkyl chain (1,2,4-trifluoro-3-(C10F21CH2O)-7-(N,N)-dimethylaminoacridine) segregation. The segregation was explored using a 1% 1,2,4-trifluoro-3-(C10F21CH2O)-7-(N,N)-dimethyla-minoacridine in two methods: film casting and spin-coating, a thin film onto preformed PMMA discs. Both methods were compared against control PMMA to determine which method provided the best hindrance against calcium containing deposits when immersed in a simulated aqueous humour solution. Characterisation of the surface using scanning electron microscopy coupled with energy;dispersive x-ray analysis indicated that the surface segregation of perfluoroalkyl chains had hindered calcification in both methods. This pleminary research shows promising results of employing perfluoroalkyl chains in the surface segregation of biomaterials that can be employed in intraocular lenses.展开更多
Electron transfer reactions between O-benzoyl t-butylhydroxyl- amine,t-BuNHOCOPh(1)and perfluorodiacyl peroxides(RfCO_2)_2(2)may serve as a novel method for generating useful t-hutyl perfluoroalkyl nitroxldes at room ...Electron transfer reactions between O-benzoyl t-butylhydroxyl- amine,t-BuNHOCOPh(1)and perfluorodiacyl peroxides(RfCO_2)_2(2)may serve as a novel method for generating useful t-hutyl perfluoroalkyl nitroxldes at room temperature in CFCl2-CF2Cl.展开更多
The reaction between 2,5-Dimethylpyrrole (1) and R_FI (2)(R_F: a, Cl(CF_2)_4; b, Cl(CF_2)_6; c, Cl(CF_2)_8; d, n-C_6F_(13); e, n-C_8F_(17)) in the presence of Na_2S_2O_4-NaHCO_3 in acetonitrile resulted in the formati...The reaction between 2,5-Dimethylpyrrole (1) and R_FI (2)(R_F: a, Cl(CF_2)_4; b, Cl(CF_2)_6; c, Cl(CF_2)_8; d, n-C_6F_(13); e, n-C_8F_(17)) in the presence of Na_2S_2O_4-NaHCO_3 in acetonitrile resulted in the formation of 2-perfluoroalkyl-2,5-dimethyl-2H-pyrrole (3) as a major product in good yield.展开更多
The epidemiological associations between the prenatal perfluoroalkyl substances(PFASs)exposure and the reproductive outcomes remain controversial.A continuous evaluation is needed to combine the inconsistent results.I...The epidemiological associations between the prenatal perfluoroalkyl substances(PFASs)exposure and the reproductive outcomes remain controversial.A continuous evaluation is needed to combine the inconsistent results.In this study,we explored the associations between PFASs exposure and the low birth weight(LBW),preterm birth and small for gestational age(SGA).The quality of selected literature,quantitative estimates,publication bias and subgroup analysis were performed on the basis of 17 retrieved articles published before December 2020.The results showed a significant positive association between the perfluorooctane sulfonate(PFOS)exposure and the risk of LBW[Odds ratio(OR)=1.17;95%confidence interval(CI):1.01,1.36;heterogeneity:P=0.30,I2=17%].The positive association was also observed between the PFOS and the risk of preterm birth(OR=1.19;95%CI:1.01,1.39,P=0.007;I2=62%).There was a paucity of evidence regarding the negative effects of perfluorooctanoic acid(PFOA),perfluorohexanesulfonic acid(PFHxS)and perfluorononanoic acid(PFNA)on the pregnancy outcomes.The findings from the subgroup analysis(the sampling period,the birth gender and biologic specimens)did not substantially altered the results of the overall pooled estimate ORs.The increased prevalence of negative birth outcomes with gestational PFASs exposure warrants further explorations from biological process perspective.展开更多
The stereoselective syntheses of (Z)-methyl 3-perfluoroalkyl-4-(3-carboethoxy-2-furanyl)-3-butenoates 5a-c were investigated. The reaction of (3-carboethoxy-2-fu-ranyl)-methyltriphenylphosphonium bromide 1 with methyl...The stereoselective syntheses of (Z)-methyl 3-perfluoroalkyl-4-(3-carboethoxy-2-furanyl)-3-butenoates 5a-c were investigated. The reaction of (3-carboethoxy-2-fu-ranyl)-methyltriphenylphosphonium bromide 1 with methyl 2-perfluoroalkynoates 2a-c in the presence of K2CO3 at room temperature gives two adducts, (E)-methyl 3-per-fluoroalkyl-4-( 3-carboethoxy-2-furanyl )-2-triphenylphosphoranylidene-3-butenoates 3a-c and (E)-methyl 3-perfluoroalkyl-4-(3-carboethoxy-2-furanyl)-4-triphenylphos-phoranylidene-2-butenoates 4a-c. (Z)-Methyl 3-perfluoroalkyl-4-(3-carboethoxy-2-furanyl)-3-butenoates 5a-c can be synthesized stereoselectively with high yields when an aqueous DMF solution of 3c, 4c or a mixture of 3a-b and 4a-b was heated at 140℃ for 8 h.展开更多
perfluoroalkyl iodides reacted with alkenes in acetonitrile solu- tion containing catalytic amount of organophosphine under mild condition to give the corresponding adducts in moderate to good yields.Reaction was show...perfluoroalkyl iodides reacted with alkenes in acetonitrile solu- tion containing catalytic amount of organophosphine under mild condition to give the corresponding adducts in moderate to good yields.Reaction was shown to involve a free radical mechanism.展开更多
The presence of fluorine in biologically active compounds can impart a profound influence on their biological active. This influence has lead to the development of several potent agricultural and therapeutic agents[1]...The presence of fluorine in biologically active compounds can impart a profound influence on their biological active. This influence has lead to the development of several potent agricultural and therapeutic agents[1]. During the study on the reactions of 4 - ethoxyl - 1, 1, 1 -trifluoromathyl-3-butenone 1, we found which is a very useful building-block in synthesis of fluoro-containing heterocyclic compounds[2]. Compound 1 can react with perfluorophenyl hydrazine and afford 1- perfluorophenyl-5-trifluoromethyl- 5 -hydroxy-4, 5 -2H- pyrazole 2 in excellent yield. It’s structure is further supported by X-ray diffraction.展开更多
Poly-and perfluoroalkyl substances(PFASs)are important environmental contaminants globally and in the early 2000s they were shown to be ubiquitous contaminants in Arctic wildlife.Previous reviews by Butt et al.and Let...Poly-and perfluoroalkyl substances(PFASs)are important environmental contaminants globally and in the early 2000s they were shown to be ubiquitous contaminants in Arctic wildlife.Previous reviews by Butt et al.and Letcher et al.have covered studies on levels and trends of PFASs in the Arctic that were available to 2009.The purpose of this review is to focus on more recent work,generally published between 2009 and 2018,with emphasis on PFASs of emerging concern such as perfluoroalkyl carboxylates(PFCAs)and short-chain perfluoroalkyl sulfonates(PFSAs)and their precursors.Atmospheric measurements over the period 2006e2014 have shown that fluorotelomer alcohols(FTOHs)as well as perfluorobutanoic acid(PFBA)and perfluoroctanoic acid(PFOA)are the most prominent PFASs in the arctic atmosphere,all with increasing concentrations at Alert although PFOA concentrations declined at the Zeppelin Station(Svalbard).Results from ice cores show generally increasing deposition of PFCAs on the Devon Ice cap in the Canadian arctic while declining fluxes were found in a glacier on Svalbard.An extensive dataset exists for long-term trends of long-chain PFCAs that have been reported in Arctic biota with some datasets including archived samples from the 1970s and 1980s.Trends in PFCAs over time vary among the same species across the North American Arctic,East and West Greenland,and Svalbard.Most long term time series show a decline from higher concentrations in the early 2000s.However there have been recent(post 2010)increasing trends of PFCAs in ringed seals in the Canadian Arctic,East Greenland polar bears and in arctic foxes in Svalbard.Annual biological sampling is helping to determine these relatively short term changes.Rising levels of some PFCAs have been explained by continued emissions of long-chain PFCAs and/or their precursors and inflows to the Arctic Ocean,especially from the North Atlantic.While the effectiveness of biological sampling for temporal trends in long-chain PFCAs and PFSAs has been demonstrated,this does not apply to the C4eC8ePFCAs,perfluorobutane sulfonamide(FBSA),or perfluorobutane sulfonate(PFBS)which are generally present at low concentrations in biota.In addition to air sampling,sampling abiotic media such as glacial cores,and annual sampling of lake waters and seawater would appear to be the best approaches for investigating trends in the less bioaccumulative PFASs.展开更多
Using Ce(SO4)2 or Mn(OAc)3 as oxidant, dibenzo crown ethers such as dibenzo-18-crown-6 (1) and dibenzo-24-crown-8 (5) and benzo-12-crown-4 (7) reacted smoothly with sodium perfluoroalkanesulfinates (2a-2e) to give the...Using Ce(SO4)2 or Mn(OAc)3 as oxidant, dibenzo crown ethers such as dibenzo-18-crown-6 (1) and dibenzo-24-crown-8 (5) and benzo-12-crown-4 (7) reacted smoothly with sodium perfluoroalkanesulfinates (2a-2e) to give the corresponding perfluoroalkylated products (3,4,6,7) in good yields with two isomers obtained in the case of dibenzo crown ethers. This provides a facile synthesis of perfluoroalkyl-containing crown ethers.展开更多
The purpose of this study was to determine perfluoroalkyl substances（PFASs） in human serum, urine, hair and nail from general populations, and to investigate the possibility for human urine, hair and nail used as th...The purpose of this study was to determine perfluoroalkyl substances（PFASs） in human serum, urine, hair and nail from general populations, and to investigate the possibility for human urine, hair and nail used as the biomonitoring sample for PFASs exposure. We detected the concentrations of PFHx A, PFOA, PFNA, PFDA, PFUn DA, PFDo A, PFHx S and PFOS in 39 matched human serum, urine, hair and nail samples from Shenzhen in China. The detection frequency and the median level of PFOS were all higher than that of the other PFASs in four matrices. The median concentration of PFOS in serum, urine, hair, and nail were 9.24 ng/mL, 13.96 ng/L, 0.58 ng/g and 0.63 ng/g, respectively. The results of spearman correlation test indicated that nail was an ideal matrix for biomonitoring PFOS rather than human urine and hair in general populations for the non-invasive sampling.展开更多
The levels of six perfluoroalkyl substances（PFASs） in surface sediment and their vertical variations in dated sediment cores from the Haihe River were investigated; studied substances included perfluorooctanoic acid...The levels of six perfluoroalkyl substances（PFASs） in surface sediment and their vertical variations in dated sediment cores from the Haihe River were investigated; studied substances included perfluorooctanoic acid（PFOA）,perfluorononanoic acid（PFNA）,perfluorooctane sulfonate（PFOS）,perfluorodecanoic acid（PFDA）,perfluoroundecanoic acid（PFUnA）,and perfluorododecanoic acid（PFDoA）. Results showed that the total PFAS concentration in surface sediment ranged between 0.52 and 16.33 ng/g dry weight（dw） with an average of3.47 ng/g dw,with PFOS and PFOA as the dominant PFASs. In general,the PFAS concentrations in the mainstream increased from the upper to the lower reaches,except that a drop occurred downstream of the Erdao dam. Although the PFASs in the sediment cores did not show a clear decreasing or increasing trend with depth,the three cores had a similar vertical variation.The PFAS levels were relatively low in the surface sediment,and reached the first high point at8–20 cm as a result of the wide use of PFASs from 1990 to 2000. After that the PFAS levels decreased,and then increased to a second high point at about 40–48 cm,which might be caused by the leaching of PFASs in sediment. Because PFASs have hydrophilic groups and relatively high solubility,the PFASs will transfer from the upper to lower layers of sediment when water infiltration occurs,leading to the fluctuation of PFAS levels in sediment cores. This study suggests that both the temporal variation of sources and transfer processes of PFASs in sediments are important factors influencing the vertical variation of PFASs in sediment cores.展开更多
This study was conducted to examine the association of perfluoroalkyl substance（PFAS）exposure with gestational diabetes mellitus（GDM） risk and postpartum fasting blood glucose.We used a 1：2 matched case–control ...This study was conducted to examine the association of perfluoroalkyl substance（PFAS）exposure with gestational diabetes mellitus（GDM） risk and postpartum fasting blood glucose.We used a 1：2 matched case–control study with 84 GDM subjects and 168 healthy pregnant women from Beijing, China. The maternal blood was collected at 1–2 days before delivery, and eight linear isomers and fourteen branched isomers were determined in maternal serum.Logistic regression analyses were performed to evaluate the associations after adjusting for potential confounders. The median of the sum of levels of total PFASs was 4.24 ng/m L with a interquartile range（IQR） of 2.82–6.54 ng/m L. Although maternal PFAS exposure was not associated with risk of GDM, significant positive associations were observed between evaluated exposure to specific PFAS congeners and increasing blood glucose. The odds ratio（ORs） of the highest category of postpartum fasting blood glucose for perfluoro-1-metylheptylsulfonat（1 m-PFOS）, perfluoro-3/4-metylheptylsulfonat（3 m＋4 m-PFOS）, perfluoro-5-metylheptylsulfonat（5 m-PFOS）, and perfluorohexane sulfonate（PFHx S） were 2.03（95% CI： 1.09–3.77）, 1.93（95% CI：1.04–3.58）, 2.48（95% CI： 1.33–4.65）, and 2.26（95% CI： 1.21–4.21）, respectively, suggesting negative effects of maternal exposure to specific PFAS compounds on glucose metabolism.展开更多
Bis[（perfluoroalkyl）sulfonyl]imides [HN（SO2Rf）2, and Rf represents the perfluorinated alkyl group] supported on MCM-41 were synthesized and characterized by XRD, FTIR, SEM, TGA and N2-adsorption techniques. The su...Bis[（perfluoroalkyl）sulfonyl]imides [HN（SO2Rf）2, and Rf represents the perfluorinated alkyl group] supported on MCM-41 were synthesized and characterized by XRD, FTIR, SEM, TGA and N2-adsorption techniques. The supported catalysts, HN（SO2Rf）2/MCM-41, were used as the catalysts for the tert-butylafion of hydroquinone （HQ） with tert-butyl alcohol （TBA） in the liquid phase. A high yield （52.0%） of 2-tert-butyl hydroquinone （TBHQ） could be obtained in the presence of 5 tool% HN（SO2C4F9）2/MCM-41 under the optimized reaction conditions and the heterogeneous catalyst could be recycled at least 6 times without substantial loss of activity.展开更多
It is extremely important to analyze the contaminative behaviors of Perfluoroalkyl acids(PFAAs) due to their serious threats to urban environments which are closely related to humans. Current study aimed to explore th...It is extremely important to analyze the contaminative behaviors of Perfluoroalkyl acids(PFAAs) due to their serious threats to urban environments which are closely related to humans. Current study aimed to explore the distribution, source apportionment and ecological risk assessment of PFAAs in surface water from Shijiazhuang, China. The concentrations of ΣPFAAs ranged from 19.5 to 125.9 ng/L in the investigation area. Perfluorobutanesulfonic acid(PFBS) and perfluoropentanoic acid(PFPeA) were the predominant contaminants(mean value: 14.3 ng/L and 16.6 ng/L, respectively). The distribution of PFAAs according to geospatial analysis and hierarchical clustering analysis(HCA) showed that higher levels of ΣPFAAs were detected in the southern surface water of Shijiazhuang and there was a stepwise decrease from the wet season to the dry season. Furthermore, based on source apportionment,the dominant potential sources were found to be wastewater treatment plant(WWTP) effluents and industrial discharge. The risk quotients(RQs) revealed low ecological risks of all PFAAs for aquatic organisms in Shijiazhuang surface water. Collectively, this study provided basic data for regulatory strategies for controlling PFAA pollutions in urban surface water.展开更多
Imagine if a group of toxic substances that increase oxidative stress and disrupt glucose and lipid metabolism have been broadly used worldwide for applications such as repellent,food packaging,and non-stick frying pa...Imagine if a group of toxic substances that increase oxidative stress and disrupt glucose and lipid metabolism have been broadly used worldwide for applications such as repellent,food packaging,and non-stick frying pan coatings.Now imagine if some of these substances have half-lives as long as 3-8 years.展开更多
Perfluoroalkyl acids(PFAAs)are emerging persistent organic pollutants that are globally distributed in the environment.In the present review,the occurrence of PFAAs and their behavior in aquatic ecosystem were summari...Perfluoroalkyl acids(PFAAs)are emerging persistent organic pollutants that are globally distributed in the environment.In the present review,the occurrence of PFAAs and their behavior in aquatic ecosystem were summarized,and the health and ecological risk assessment and the multimedia fate simulation were investigated.PFAAs are most likely to exist in the aqueous phase,and PFAAs in atmosphere are also able to enter water bodies through diffusion and wet and dry deposition and eventually become widely distributed in various environmental media.The air-solid partition is considered to be one of the major factors in the long-distance transportation of the pollutants.The pKa values and organic carbon fraction of the sediment could influence the partition of PFAAs between water and sediment.Otherwise,PFAAs have teratogenic,mutagenic and other toxic effects and they could be accumulated by biota,and magnified through trophic level.The ecological and health risks of PFOA and PFOS were assessment.In order to explore the partition mechanism and reduce the uncertainty of the simulation of the transport,transformation and fate,the experimental methods on physicochemical properties of PFAAs should be developed.Moreover,further studies on toxicities of PFAAs are necessary for health and ecological risk assessment.展开更多
Receptor models have been proved as useful tools to identify source categories and quantitatively calculate the contributions of extracted sources.In this study,sixty surface sediment samples were collected from fourt...Receptor models have been proved as useful tools to identify source categories and quantitatively calculate the contributions of extracted sources.In this study,sixty surface sediment samples were collected from fourteen lakes in Jiangsu Province,China.The total concentrations of C_4–C_（14）-perfluoroalkyl carboxylic acids and perfluorooctane sulfonic acid（∑_（12）PFASs） in sediments ranged from 0.264 to 4.44 ng/g dw（dry weight）,with an average of 1.76 ng/g dw.Three commonly-applied receptor models,namely principal component analysis-multiple linear regression（PCA-MLR）,positive matrix factorization（PMF） and Unmix models,were employed to apportion PFAS sources in sediments.Overall,these three models all could well track the ∑_（12） PFASs concentrations as well as the concentrations explained in sediments.These three models identified consistently four PFAS sources：the textile treatment sources,the fluoropolymer processing aid/fluororesin coating sources,the textile treatment/metal plating sources and the precious metal sources,contributing 28.1%,37.0%,29.7% and 5.3% by PCA-MLR model,30.60%,39.3%,22.4% and 7.7% by PMF model,and 20.6%,52.4%,20.2% and 6.8% by Unmix model to the ∑_（12） PFASs,respectively.Comparative statistics of multiple analytical methods could minimize individual-method weaknesses and provide convergent results to enhance the persuasiveness of the conclusions.The findings could give us a better knowledge of PFAS sources in aquatic environments.展开更多
Perfluorinated compounds(PFCs)are ubiquitously distributed in the environment mainly as perfluorocarboxylic acids(PFCAs)and perfluoroalkyl sulfonates(PFASs).In this paper,six PFCAs and two PFASs were quantified in sur...Perfluorinated compounds(PFCs)are ubiquitously distributed in the environment mainly as perfluorocarboxylic acids(PFCAs)and perfluoroalkyl sulfonates(PFASs).In this paper,six PFCAs and two PFASs were quantified in surface and tap water samples from 12 sites around Lake Taihu near Shanghai City in East China.Predominant PFCs were perfluorooctanoic acid(PFOA)and perfluorooctane sulfonate(PFOS),of which the concentration ranges were 6.8–206 and 1.2–45 ng·L^(–1),the geometric means were 35.3 and 9.4 ng·L^(–1),and the median(quartile range)values were 31.4(34.4)and 10.4(10.7)ng·L^(–1),respectively.Other PFCs were also detected but in much lower concentrations than PFOA.The sources of the PFCs were expected to be direct industrial discharges in the Lake Taihu area,and this area was also a possible source of PFCs contaminations in Shanghai district in the downstream.PFCs distributions were found different in the upstream,downstream and north part of Lake Taihu.Occurrences of PFCs in the tap water in Lake Taihu area indicated their exposure to the local people.A brief estimation of the environmental risks by PFCs implied no acute or immediate risks from PFCs to local human health,but chronic risks from PFOA in the tap water should be considered in the downstream regions.展开更多
基金supported by the Gansu Provincial Science and Technology Program(22ZD6FA005)West Light Foundation of The Chinese Academy of Sciences(xbzg-zdsys-202306)+2 种基金Science Fund for Creative Research Groups of Gansu Province(Grant No.23JRRA567)Taishan Scholars Program of Shandong Province(No.tsqn202312158)Key Research and Development Program of Gansu Province(22YF7FA041)。
文摘Perfluoroalkyl acid analogs(PFAAs)are a class of chemically stable environmentally persistent organic pollutants(POPs)that are difficult to degrade and have a strong capacity to accumulate in the human body.PFAAs have been found to be biotoxic to humans and have been detected in various environmental media,especially in the cryosphere at trace concentrations.The cryosphere,sensitively responds to climate change,plays a crucial role in the global water,carbon and energy cycles.However,researches on cryosphere PFAAs especially in Tibetan Plateau(TP)is limited.Therefore,we summarize the physicochemical properties,physiological toxicity,spatiotemporal distribution,sources,diffusion and migration pathways,as well as analysis and removal methods of PFAAs in the cryosphere regions.The results show that PFAAs pollutants are mainly produced and distributed in the more economically developed countries in Europe and the United States,as well as in East Asia,and PFAAs can be transported by atmospheric circulation and water cycle to remote regions including cryosphere regions.The current detection methods for PFAAs in cryosphere need to be further refined for increased accuracy and convenience.There is also a need to develop more effective removal methods that will reduce the environmental and human threats posed by these PFAAs.Finally,we propose key scientific questions for future research in cryosphere including PFAAs redistribution influenced by cryosphere changes,human activities,and the interaction of other spheres.
文摘Intraocular lenses can be manufactured from a wide variety of polymers, but due to the lost cost associated with the use of Poly (methyl methacrylate) (PMMA), it is still the preferred material used in the developing countries. However, a major drawback to its use is the build-up of calcium containing deposits that are formed on the intraocular lens over a period of time. In an attempt to hinder this deposition, surface modification of medical grade PMMA has been carried out using perfluoroalkyl chain (1,2,4-trifluoro-3-(C10F21CH2O)-7-(N,N)-dimethylaminoacridine) segregation. The segregation was explored using a 1% 1,2,4-trifluoro-3-(C10F21CH2O)-7-(N,N)-dimethyla-minoacridine in two methods: film casting and spin-coating, a thin film onto preformed PMMA discs. Both methods were compared against control PMMA to determine which method provided the best hindrance against calcium containing deposits when immersed in a simulated aqueous humour solution. Characterisation of the surface using scanning electron microscopy coupled with energy;dispersive x-ray analysis indicated that the surface segregation of perfluoroalkyl chains had hindered calcification in both methods. This pleminary research shows promising results of employing perfluoroalkyl chains in the surface segregation of biomaterials that can be employed in intraocular lenses.
文摘Electron transfer reactions between O-benzoyl t-butylhydroxyl- amine,t-BuNHOCOPh(1)and perfluorodiacyl peroxides(RfCO_2)_2(2)may serve as a novel method for generating useful t-hutyl perfluoroalkyl nitroxldes at room temperature in CFCl2-CF2Cl.
文摘The reaction between 2,5-Dimethylpyrrole (1) and R_FI (2)(R_F: a, Cl(CF_2)_4; b, Cl(CF_2)_6; c, Cl(CF_2)_8; d, n-C_6F_(13); e, n-C_8F_(17)) in the presence of Na_2S_2O_4-NaHCO_3 in acetonitrile resulted in the formation of 2-perfluoroalkyl-2,5-dimethyl-2H-pyrrole (3) as a major product in good yield.
基金National Natural Science Foundation of China(No.22006010)Shanghai Sailing Program,China(No.19YF1400500)。
文摘The epidemiological associations between the prenatal perfluoroalkyl substances(PFASs)exposure and the reproductive outcomes remain controversial.A continuous evaluation is needed to combine the inconsistent results.In this study,we explored the associations between PFASs exposure and the low birth weight(LBW),preterm birth and small for gestational age(SGA).The quality of selected literature,quantitative estimates,publication bias and subgroup analysis were performed on the basis of 17 retrieved articles published before December 2020.The results showed a significant positive association between the perfluorooctane sulfonate(PFOS)exposure and the risk of LBW[Odds ratio(OR)=1.17;95%confidence interval(CI):1.01,1.36;heterogeneity:P=0.30,I2=17%].The positive association was also observed between the PFOS and the risk of preterm birth(OR=1.19;95%CI:1.01,1.39,P=0.007;I2=62%).There was a paucity of evidence regarding the negative effects of perfluorooctanoic acid(PFOA),perfluorohexanesulfonic acid(PFHxS)and perfluorononanoic acid(PFNA)on the pregnancy outcomes.The findings from the subgroup analysis(the sampling period,the birth gender and biologic specimens)did not substantially altered the results of the overall pooled estimate ORs.The increased prevalence of negative birth outcomes with gestational PFASs exposure warrants further explorations from biological process perspective.
基金Supported by the National Natural Science Foundation of ChinaFor part XVII of the series, see Chinese J. of Chem. (to be published)
文摘The stereoselective syntheses of (Z)-methyl 3-perfluoroalkyl-4-(3-carboethoxy-2-furanyl)-3-butenoates 5a-c were investigated. The reaction of (3-carboethoxy-2-fu-ranyl)-methyltriphenylphosphonium bromide 1 with methyl 2-perfluoroalkynoates 2a-c in the presence of K2CO3 at room temperature gives two adducts, (E)-methyl 3-per-fluoroalkyl-4-( 3-carboethoxy-2-furanyl )-2-triphenylphosphoranylidene-3-butenoates 3a-c and (E)-methyl 3-perfluoroalkyl-4-(3-carboethoxy-2-furanyl)-4-triphenylphos-phoranylidene-2-butenoates 4a-c. (Z)-Methyl 3-perfluoroalkyl-4-(3-carboethoxy-2-furanyl)-3-butenoates 5a-c can be synthesized stereoselectively with high yields when an aqueous DMF solution of 3c, 4c or a mixture of 3a-b and 4a-b was heated at 140℃ for 8 h.
文摘perfluoroalkyl iodides reacted with alkenes in acetonitrile solu- tion containing catalytic amount of organophosphine under mild condition to give the corresponding adducts in moderate to good yields.Reaction was shown to involve a free radical mechanism.
基金The authors thank the National Natural Science Foundation ofChina (NNSFC) !(No. 29872051 and No 29672041 ) for financial support
文摘The presence of fluorine in biologically active compounds can impart a profound influence on their biological active. This influence has lead to the development of several potent agricultural and therapeutic agents[1]. During the study on the reactions of 4 - ethoxyl - 1, 1, 1 -trifluoromathyl-3-butenone 1, we found which is a very useful building-block in synthesis of fluoro-containing heterocyclic compounds[2]. Compound 1 can react with perfluorophenyl hydrazine and afford 1- perfluorophenyl-5-trifluoromethyl- 5 -hydroxy-4, 5 -2H- pyrazole 2 in excellent yield. It’s structure is further supported by X-ray diffraction.
基金We thank the Arctic Monitoring and Assessment Programme(AMAP)and the national programs in the circumpolar countries for their funding and support of this work.We are especially grateful to Simon Wilson,Cynthia de Wit,and the reviewers that read the chapter on PFASs in the original AMAP assessment.We are thankful to the northern communities in circumpolar regions for their cooperation and collection of biological samples that yielded the data reviewed here.DCGM was supported by the King Carl XVI Gustaf Professorship in Environmental Science at the Dept of Environmental Science and Analytical Chemistry,Stockholm University during 2018-19.
文摘Poly-and perfluoroalkyl substances(PFASs)are important environmental contaminants globally and in the early 2000s they were shown to be ubiquitous contaminants in Arctic wildlife.Previous reviews by Butt et al.and Letcher et al.have covered studies on levels and trends of PFASs in the Arctic that were available to 2009.The purpose of this review is to focus on more recent work,generally published between 2009 and 2018,with emphasis on PFASs of emerging concern such as perfluoroalkyl carboxylates(PFCAs)and short-chain perfluoroalkyl sulfonates(PFSAs)and their precursors.Atmospheric measurements over the period 2006e2014 have shown that fluorotelomer alcohols(FTOHs)as well as perfluorobutanoic acid(PFBA)and perfluoroctanoic acid(PFOA)are the most prominent PFASs in the arctic atmosphere,all with increasing concentrations at Alert although PFOA concentrations declined at the Zeppelin Station(Svalbard).Results from ice cores show generally increasing deposition of PFCAs on the Devon Ice cap in the Canadian arctic while declining fluxes were found in a glacier on Svalbard.An extensive dataset exists for long-term trends of long-chain PFCAs that have been reported in Arctic biota with some datasets including archived samples from the 1970s and 1980s.Trends in PFCAs over time vary among the same species across the North American Arctic,East and West Greenland,and Svalbard.Most long term time series show a decline from higher concentrations in the early 2000s.However there have been recent(post 2010)increasing trends of PFCAs in ringed seals in the Canadian Arctic,East Greenland polar bears and in arctic foxes in Svalbard.Annual biological sampling is helping to determine these relatively short term changes.Rising levels of some PFCAs have been explained by continued emissions of long-chain PFCAs and/or their precursors and inflows to the Arctic Ocean,especially from the North Atlantic.While the effectiveness of biological sampling for temporal trends in long-chain PFCAs and PFSAs has been demonstrated,this does not apply to the C4eC8ePFCAs,perfluorobutane sulfonamide(FBSA),or perfluorobutane sulfonate(PFBS)which are generally present at low concentrations in biota.In addition to air sampling,sampling abiotic media such as glacial cores,and annual sampling of lake waters and seawater would appear to be the best approaches for investigating trends in the less bioaccumulative PFASs.
文摘Using Ce(SO4)2 or Mn(OAc)3 as oxidant, dibenzo crown ethers such as dibenzo-18-crown-6 (1) and dibenzo-24-crown-8 (5) and benzo-12-crown-4 (7) reacted smoothly with sodium perfluoroalkanesulfinates (2a-2e) to give the corresponding perfluoroalkylated products (3,4,6,7) in good yields with two isomers obtained in the case of dibenzo crown ethers. This provides a facile synthesis of perfluoroalkyl-containing crown ethers.
基金funded by the National Natural Science of Foundation of China(Nos.21537001 and 21407033)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB14010100)
文摘The purpose of this study was to determine perfluoroalkyl substances（PFASs） in human serum, urine, hair and nail from general populations, and to investigate the possibility for human urine, hair and nail used as the biomonitoring sample for PFASs exposure. We detected the concentrations of PFHx A, PFOA, PFNA, PFDA, PFUn DA, PFDo A, PFHx S and PFOS in 39 matched human serum, urine, hair and nail samples from Shenzhen in China. The detection frequency and the median level of PFOS were all higher than that of the other PFASs in four matrices. The median concentration of PFOS in serum, urine, hair, and nail were 9.24 ng/mL, 13.96 ng/L, 0.58 ng/g and 0.63 ng/g, respectively. The results of spearman correlation test indicated that nail was an ideal matrix for biomonitoring PFOS rather than human urine and hair in general populations for the non-invasive sampling.
基金supported by the Major State Basic Research Development Program (No.2010CB951104)the National Science Foundation for Distinguished Young Scholars (No.51325902)+1 种基金the Specialized Research Fund for the Doctoral Program of Higher Education (No.20110003110030)the National Natural Science Foundation of China (No.51279010)
文摘The levels of six perfluoroalkyl substances（PFASs） in surface sediment and their vertical variations in dated sediment cores from the Haihe River were investigated; studied substances included perfluorooctanoic acid（PFOA）,perfluorononanoic acid（PFNA）,perfluorooctane sulfonate（PFOS）,perfluorodecanoic acid（PFDA）,perfluoroundecanoic acid（PFUnA）,and perfluorododecanoic acid（PFDoA）. Results showed that the total PFAS concentration in surface sediment ranged between 0.52 and 16.33 ng/g dry weight（dw） with an average of3.47 ng/g dw,with PFOS and PFOA as the dominant PFASs. In general,the PFAS concentrations in the mainstream increased from the upper to the lower reaches,except that a drop occurred downstream of the Erdao dam. Although the PFASs in the sediment cores did not show a clear decreasing or increasing trend with depth,the three cores had a similar vertical variation.The PFAS levels were relatively low in the surface sediment,and reached the first high point at8–20 cm as a result of the wide use of PFASs from 1990 to 2000. After that the PFAS levels decreased,and then increased to a second high point at about 40–48 cm,which might be caused by the leaching of PFASs in sediment. Because PFASs have hydrophilic groups and relatively high solubility,the PFASs will transfer from the upper to lower layers of sediment when water infiltration occurs,leading to the fluctuation of PFAS levels in sediment cores. This study suggests that both the temporal variation of sources and transfer processes of PFASs in sediments are important factors influencing the vertical variation of PFASs in sediment cores.
基金supported by the National Natural Science Foundation of China(Nos.21537001and 21477030)the National Key Research and Development Program of China(No.2017YFC1600502)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB14010100)
文摘This study was conducted to examine the association of perfluoroalkyl substance（PFAS）exposure with gestational diabetes mellitus（GDM） risk and postpartum fasting blood glucose.We used a 1：2 matched case–control study with 84 GDM subjects and 168 healthy pregnant women from Beijing, China. The maternal blood was collected at 1–2 days before delivery, and eight linear isomers and fourteen branched isomers were determined in maternal serum.Logistic regression analyses were performed to evaluate the associations after adjusting for potential confounders. The median of the sum of levels of total PFASs was 4.24 ng/m L with a interquartile range（IQR） of 2.82–6.54 ng/m L. Although maternal PFAS exposure was not associated with risk of GDM, significant positive associations were observed between evaluated exposure to specific PFAS congeners and increasing blood glucose. The odds ratio（ORs） of the highest category of postpartum fasting blood glucose for perfluoro-1-metylheptylsulfonat（1 m-PFOS）, perfluoro-3/4-metylheptylsulfonat（3 m＋4 m-PFOS）, perfluoro-5-metylheptylsulfonat（5 m-PFOS）, and perfluorohexane sulfonate（PFHx S） were 2.03（95% CI： 1.09–3.77）, 1.93（95% CI：1.04–3.58）, 2.48（95% CI： 1.33–4.65）, and 2.26（95% CI： 1.21–4.21）, respectively, suggesting negative effects of maternal exposure to specific PFAS compounds on glucose metabolism.
文摘Bis[（perfluoroalkyl）sulfonyl]imides [HN（SO2Rf）2, and Rf represents the perfluorinated alkyl group] supported on MCM-41 were synthesized and characterized by XRD, FTIR, SEM, TGA and N2-adsorption techniques. The supported catalysts, HN（SO2Rf）2/MCM-41, were used as the catalysts for the tert-butylafion of hydroquinone （HQ） with tert-butyl alcohol （TBA） in the liquid phase. A high yield （52.0%） of 2-tert-butyl hydroquinone （TBHQ） could be obtained in the presence of 5 tool% HN（SO2C4F9）2/MCM-41 under the optimized reaction conditions and the heterogeneous catalyst could be recycled at least 6 times without substantial loss of activity.
基金supported by the National Natural Science Foundation of China (Nos. 41907321, 21777182)the Natural Science Foundation of Hebei Province (No. B2019208273)State Key Laboratory of Environmental Chemistry and Ecotoxicology, RCEES, Chinese Academy of Sciences (No. KF2018-17)。
文摘It is extremely important to analyze the contaminative behaviors of Perfluoroalkyl acids(PFAAs) due to their serious threats to urban environments which are closely related to humans. Current study aimed to explore the distribution, source apportionment and ecological risk assessment of PFAAs in surface water from Shijiazhuang, China. The concentrations of ΣPFAAs ranged from 19.5 to 125.9 ng/L in the investigation area. Perfluorobutanesulfonic acid(PFBS) and perfluoropentanoic acid(PFPeA) were the predominant contaminants(mean value: 14.3 ng/L and 16.6 ng/L, respectively). The distribution of PFAAs according to geospatial analysis and hierarchical clustering analysis(HCA) showed that higher levels of ΣPFAAs were detected in the southern surface water of Shijiazhuang and there was a stepwise decrease from the wet season to the dry season. Furthermore, based on source apportionment,the dominant potential sources were found to be wastewater treatment plant(WWTP) effluents and industrial discharge. The risk quotients(RQs) revealed low ecological risks of all PFAAs for aquatic organisms in Shijiazhuang surface water. Collectively, this study provided basic data for regulatory strategies for controlling PFAA pollutions in urban surface water.
文摘Imagine if a group of toxic substances that increase oxidative stress and disrupt glucose and lipid metabolism have been broadly used worldwide for applications such as repellent,food packaging,and non-stick frying pan coatings.Now imagine if some of these substances have half-lives as long as 3-8 years.
基金Funding for this study was provided by the National Natural Science Foundation of China(NSFC)(41271462)the Undergraduate Student Research Training Program of the Ministry of Education.
文摘Perfluoroalkyl acids(PFAAs)are emerging persistent organic pollutants that are globally distributed in the environment.In the present review,the occurrence of PFAAs and their behavior in aquatic ecosystem were summarized,and the health and ecological risk assessment and the multimedia fate simulation were investigated.PFAAs are most likely to exist in the aqueous phase,and PFAAs in atmosphere are also able to enter water bodies through diffusion and wet and dry deposition and eventually become widely distributed in various environmental media.The air-solid partition is considered to be one of the major factors in the long-distance transportation of the pollutants.The pKa values and organic carbon fraction of the sediment could influence the partition of PFAAs between water and sediment.Otherwise,PFAAs have teratogenic,mutagenic and other toxic effects and they could be accumulated by biota,and magnified through trophic level.The ecological and health risks of PFOA and PFOS were assessment.In order to explore the partition mechanism and reduce the uncertainty of the simulation of the transport,transformation and fate,the experimental methods on physicochemical properties of PFAAs should be developed.Moreover,further studies on toxicities of PFAAs are necessary for health and ecological risk assessment.
基金supported by the Mega-projects of Science Research for Water Environmental Improvement(No.2012ZX07101-002)the National Natural Science Foundation of China(No.41521003)
文摘Receptor models have been proved as useful tools to identify source categories and quantitatively calculate the contributions of extracted sources.In this study,sixty surface sediment samples were collected from fourteen lakes in Jiangsu Province,China.The total concentrations of C_4–C_（14）-perfluoroalkyl carboxylic acids and perfluorooctane sulfonic acid（∑_（12）PFASs） in sediments ranged from 0.264 to 4.44 ng/g dw（dry weight）,with an average of 1.76 ng/g dw.Three commonly-applied receptor models,namely principal component analysis-multiple linear regression（PCA-MLR）,positive matrix factorization（PMF） and Unmix models,were employed to apportion PFAS sources in sediments.Overall,these three models all could well track the ∑_（12） PFASs concentrations as well as the concentrations explained in sediments.These three models identified consistently four PFAS sources：the textile treatment sources,the fluoropolymer processing aid/fluororesin coating sources,the textile treatment/metal plating sources and the precious metal sources,contributing 28.1%,37.0%,29.7% and 5.3% by PCA-MLR model,30.60%,39.3%,22.4% and 7.7% by PMF model,and 20.6%,52.4%,20.2% and 6.8% by Unmix model to the ∑_（12） PFASs,respectively.Comparative statistics of multiple analytical methods could minimize individual-method weaknesses and provide convergent results to enhance the persuasiveness of the conclusions.The findings could give us a better knowledge of PFAS sources in aquatic environments.
基金the National Science and Technology Pillar Program of China(Grant No.2006BAC19B06)the Major Projects on Control and Rectification of Water Body Pollution(2009ZX07313-003).
文摘Perfluorinated compounds(PFCs)are ubiquitously distributed in the environment mainly as perfluorocarboxylic acids(PFCAs)and perfluoroalkyl sulfonates(PFASs).In this paper,six PFCAs and two PFASs were quantified in surface and tap water samples from 12 sites around Lake Taihu near Shanghai City in East China.Predominant PFCs were perfluorooctanoic acid(PFOA)and perfluorooctane sulfonate(PFOS),of which the concentration ranges were 6.8–206 and 1.2–45 ng·L^(–1),the geometric means were 35.3 and 9.4 ng·L^(–1),and the median(quartile range)values were 31.4(34.4)and 10.4(10.7)ng·L^(–1),respectively.Other PFCs were also detected but in much lower concentrations than PFOA.The sources of the PFCs were expected to be direct industrial discharges in the Lake Taihu area,and this area was also a possible source of PFCs contaminations in Shanghai district in the downstream.PFCs distributions were found different in the upstream,downstream and north part of Lake Taihu.Occurrences of PFCs in the tap water in Lake Taihu area indicated their exposure to the local people.A brief estimation of the environmental risks by PFCs implied no acute or immediate risks from PFCs to local human health,but chronic risks from PFOA in the tap water should be considered in the downstream regions.
