The degradation of partially hydrolyzed polyacrylamide(HPAM) found in alkaline/surfactant/polymer flooding sewage was investigated using Fenton-type reagents. Different Fenton reagent treatments for HPAM degradation w...The degradation of partially hydrolyzed polyacrylamide(HPAM) found in alkaline/surfactant/polymer flooding sewage was investigated using Fenton-type reagents. Different Fenton reagent treatments for HPAM degradation were compared. The effects of pH, hydrogen peroxide(H_(2)O_(2)), ferrous ion(Fe^(2+)), and tartaric ion(C_(4)H_(4)O_(6)^(2-)) concentrations were studied. The degradation reaction occurred within a wide range of pH(3–9). The HPAM degradation performance of photo-Fenton processes using solar light and UV were compared with that of the Fenton process. The degradation rate was found to be strongly dependent on the H_(2)O_(2)/Fe^(2+)/C_(4)H_(4)O_(6)^(2-)molar ratio. The HPAM degradation efficiency was 90%, and the chemical oxygen demand removal efficiency was 85%. HPAM could be degraded into a compound with a lower molecular weight, but it was difficult to achieve complete mineralization to CO_(2). The presence of intermediate products hindered further oxidation in the Fenton process.展开更多
Ilmenite is an essential mineral for the extraction of titanium.Conventional physical separation methods have difficulty recovering fine ilmenite,and dressing plants have begun applying flotation to recover ilmenite.T...Ilmenite is an essential mineral for the extraction of titanium.Conventional physical separation methods have difficulty recovering fine ilmenite,and dressing plants have begun applying flotation to recover ilmenite.The interaction of reagent groups with Ti and Fe sites on the ilmenite surface dramatically influences the ilmenite flotation.However,the investigation on Fe sites has received more attention because the activity of Ti is lower than that of Fe.For the activators on ilmenite flotation,most are metal ions but typically lead ions.The metal ions of activators promote ilmenite flotation by increasing the active sites on the ilmenite surface.Combined reagents have a better selective separation of ilmenite than single reagents due to their synergistic effect.Combining the lead ion(Pb^(2+))and the benzyl hydroxamic acid(BHA)into a Pb-BHA complex has a marked effect on ilmenite flotation,which puts forward a new idea of developing combined reagents for ilmenite flotation.This review considers reagent types and action mechanisms in ilmenite flotation.On the basis of the analysis of previous research,a brief future outlook of reagent types and action mechanisms in ilmenite flotation is also proposed in this study.展开更多
Na2SiO3 and Na2SeO3 were chosen as stable reagents of alkaline thiourea solution substituting Na2SO3, according to the structure-property relationship between the stability of alkaline thiourea and the structure of th...Na2SiO3 and Na2SeO3 were chosen as stable reagents of alkaline thiourea solution substituting Na2SO3, according to the structure-property relationship between the stability of alkaline thiourea and the structure of thiourea and sulfite ion, and the effect of the stable reagents on stability of alkaline thiourea was investigated. The results show that contrary to Na2SeO3, Na2SO3 and Na2SiO3 affect the stability of alkaline thiourea solution remarkably. The stable effect of Na2SiO3 on alkaline thiourea is obviously better than that of Na2SO3. The stable reagents Na2SO3 and Na2SiO3 decrease the decomposition rate of alkaline thiourea solution greatly, and the decomposition rate of alkaline thiourea reduces from (72.5%) to (33.8%) with addition of (0.3 mol·L-1) Na2SiO3. Dissolution currents of gold in the alkaline thiourea solution containing Na2SO3 and Na2SiO3 are (2.0) (mA·cm-2) and (3.5) (mA·cm-2) at the potential of 0.42 V, respectively, and Na2SO3 is consumed excessively due to the oxidation reaction of Na2SO3 occurring in the studied potential range. Na2SiO3 is an efficient stable reagent of alkaline thiourea solution, and gold dissolution is accelerated much more obviously by Na2SiO3 than by Na2SO3.展开更多
Substituted PhMgX and PhTi(OCHMe2)4MgX react with 3,5-O-isopropylidene-L-glucurono-γ-lactone 4 to give tetrads 5a-e and its stereoisomers 6a-e Tetrads 5a-e are the important intermediates in the synthesis of howiinol...Substituted PhMgX and PhTi(OCHMe2)4MgX react with 3,5-O-isopropylidene-L-glucurono-γ-lactone 4 to give tetrads 5a-e and its stereoisomers 6a-e Tetrads 5a-e are the important intermediates in the synthesis of howiinol Al and its derivatives. The stereoselectivities of substituted PhTi(OCHMe2)4Mg (5a-e:6a-e ratio, 68-72:32-28) were better than those of substituted PhMgX(33-64:67-36) in the reaction. The effects of different substitUted groups and positions (p-Me, m-Me, o-MeO, p-Cl) of the phenyl ring on their stereoselectivies were not significant.展开更多
An environmentally benign and practical preparation method for the Vilsmeier-Haack reagent (VH) has been developed by using phthaloyl dichloride with DMF in toluene or 2-chlorotoluene. Phthalic anhydride as the byprod...An environmentally benign and practical preparation method for the Vilsmeier-Haack reagent (VH) has been developed by using phthaloyl dichloride with DMF in toluene or 2-chlorotoluene. Phthalic anhydride as the byproduct was recovered in high yield by simple filtration. Some aromatic acids have been transformed into the corresponding acid chlorides in good yields by employing the isolated VH. Treatment of primary or secondary alcohols with VH gave alkyl formates or alkyl chlorides by depending on the reaction conditions.展开更多
Addition reaction of Grignard’s reagent to 5-methoxy-2(5H)-furanone 1 was accomplished, which provided a new possible route for synthesizing β-alkyl-γ-alkyloxy-γ-butyrolactone. A novel concise method of preparing ...Addition reaction of Grignard’s reagent to 5-methoxy-2(5H)-furanone 1 was accomplished, which provided a new possible route for synthesizing β-alkyl-γ-alkyloxy-γ-butyrolactone. A novel concise method of preparing fused heterocyclic compounds was offered by 1,3-dipolar cycloaddition reaction of silyl nitronates to 1.展开更多
Topological method is applied firstly to calculate the group connectivity indexes of some flotation reagents for sulfide minerals and oxide minerals. The study reveals that some properties of flotation reagents, such ...Topological method is applied firstly to calculate the group connectivity indexes of some flotation reagents for sulfide minerals and oxide minerals. The study reveals that some properties of flotation reagents, such as group electronegativity, energy criterion, solubility product of chemicals and maximum wavelength of ultraviolet absorbency, have linear correlation with the first order group connectivity index (GCI) of polar group, and the related coefficients are all larger than 0.900. The GCI can be used to characterize the structure of groups, and is a sort of new effective structural parameter to study the quantitative structure activity relationship of flotation reagents.展开更多
-This paper first presents a new potassium reagent and efficient enrichment agent for direct recovery of potassium from seawater, i. e. , 1, 2, 4, 5-tetrahydroxybenzen -O, O’ , O", O’’’- tetraacetic acid (TTA...-This paper first presents a new potassium reagent and efficient enrichment agent for direct recovery of potassium from seawater, i. e. , 1, 2, 4, 5-tetrahydroxybenzen -O, O’ , O", O’’’- tetraacetic acid (TTAH4). The synthetic method of TTAH4, its enrichment behaviour for potassium ion in low concentration solution and seawater, and the chemical structure of its corresponding potassium salt have been investigated. A mechanism which caused the uptake of potassium ion is suggested. Elementary analysis and IR-spectrum determination of the potassium salt proved correct evidence for a polynuclear complex, i. e. , (TTAH3K)n. Thus, the mechanism which caused the uptake of potassium ion may be interpreted in terms of the formation of polynuclear chains as a continual sandwich type coordination complex.展开更多
Lithium ion capacitors(LICs)have been widely used as energy storage devices due to their high energy density and high power density.For LICs,pre-lithiation of negative electrode is necessary.In this work,we employ a b...Lithium ion capacitors(LICs)have been widely used as energy storage devices due to their high energy density and high power density.For LICs,pre-lithiation of negative electrode is necessary.In this work,we employ a bifunctional Li6CoO4(LCO)as cathodic pre-lithiation reagent to improve the electrochemical performance of LICs.The synthesized LCO exhibited high first charge specific capacity of 721 mAh g-1and extremely low initial coulombic efficiency of 3.19%,providing sufficient Li+ for the pre-lithiation of negative electrode in the first charge.Simultaneously,Li6–xCoOy is generated from LCO during the first charge process,which exhibits pseudocapacitive property and contributes to capacity in form of surface capacitance during subsequent cycles,increasing the capacity of capacitive positive electrode.With the appropriate amounts of addition to the positive side in LICs,this bifunctional prelithiation reagent LCO shows significantly improved the electrochemical performance with the energy density of 78.5 Wh kg-1after 300 cycles between 2.0 and 4.2 V at 250 mA g-1.展开更多
Nitration of aromatic Compounds is triggered by Vilsmeier-Haack reagent (DMF/POCl3) or (DMF/SOCl2) in the presence of KNO3 or NaNO2 under conventional and non-conventional conditions. The reactions af- forded correspo...Nitration of aromatic Compounds is triggered by Vilsmeier-Haack reagent (DMF/POCl3) or (DMF/SOCl2) in the presence of KNO3 or NaNO2 under conventional and non-conventional conditions. The reactions af- forded corresponding Nitro derivatives in very good yield with high regioselectivity. The results obtained in non-conventional methods (Micro wave irradiation, Grinding, Sonication) are comparable with those ob- tained under conventional conditions, but the reaction times of former conditions are substantially shorter than that of the latter.展开更多
The influence of the precipitating reagents and dispersants on the formation of nano-aluminum hydroxide from sodium aluminate solution by chemical precipitation was investigated. The influence of the dispersed seeds o...The influence of the precipitating reagents and dispersants on the formation of nano-aluminum hydroxide from sodium aluminate solution by chemical precipitation was investigated. The influence of the dispersed seeds on the decomposi-tion process was investigated too. The alkaline aluminate solutions were used as original solutions with a concentration of Al2O3 having 14.78 g/dm3, αk—1.6 and127 g/dm3, αk—1.6. For the precipitation processes there were used follow-ing precipitating reagents—solutions HCl, NaHCO3 and NH4HCO3 with a concentration of 80 g/dm3, dispersants—PEG 6000, (NaPO3)6 and Tween 20. For the decomposition process the dispersed seeds and factories seeds were used. Structural studies of the aluminum hydroxide particles were carried out by means of the electron-probe microanalysis and scanning electron microscopy, and phase composition of products was determined by means of X-ray diffraction analysis. Ammonium bicarbonate and Tween 20 were determined as the optimal precipitating reagent and dispersant, correspondingly, resulting in dispersed aluminum hydroxide, which is used as a seed in the decomposition process. It was established that this product in form of dispersed seed considerably reduces the duration of the decomposition process;the maximal decomposition of solution (73.9%) was observed after injection of dispersеd aluminum hydroxide into solution. The final aluminum hydroxide having 90% of particles less than 100 nanometers was obtained within 7 hours of steady decreasing temperature from 70°C to 48°C.展开更多
Avian influenza(AI)is one of the most relevant viruses in the poultry industry.The AI virus(AIV)transmission from birds to human causing severe cases and mortality enhanced the magnitude of AI for public health.Conseq...Avian influenza(AI)is one of the most relevant viruses in the poultry industry.The AI virus(AIV)transmission from birds to human causing severe cases and mortality enhanced the magnitude of AI for public health.Consequently,the AIV diagnosis laboratories should be able to detect and identify endemic,epidemic and seasonal influenza strains and other wildlife influenza subtypes that cross the country’s borders.The development in quality controls in according with international rules comes to improve the performance of tests.With this purpose,the Brazilian Reference Laboratory for Avian Influenza(LANAGRO-SP)established a cooperation with the World Organization for Animal Health(OIE)to produce AIV master seeds,inactivated antigens and antiserum to attend the necessities of Brazil and other South America countries under the high quality control for all test.Seventeen of AIV master seed lots and seventeen of inactivated antigens lots produced reached hemagglutination(HA)titers of 1:512 and 1:256,respectively.In addition,fifteen AIV antiserum lots with hemagglutination inhibition(HI)titers reaching 1:4,096 were obtained.The AIV reference reagents produced and applied in laboratory routine successfully.展开更多
基金the Northeast Petroleum University Youth Science Foundation (No. 2019QNL-35)Guiding Science and Technology Plan Project of Daqing (No. zd-2021-39)。
文摘The degradation of partially hydrolyzed polyacrylamide(HPAM) found in alkaline/surfactant/polymer flooding sewage was investigated using Fenton-type reagents. Different Fenton reagent treatments for HPAM degradation were compared. The effects of pH, hydrogen peroxide(H_(2)O_(2)), ferrous ion(Fe^(2+)), and tartaric ion(C_(4)H_(4)O_(6)^(2-)) concentrations were studied. The degradation reaction occurred within a wide range of pH(3–9). The HPAM degradation performance of photo-Fenton processes using solar light and UV were compared with that of the Fenton process. The degradation rate was found to be strongly dependent on the H_(2)O_(2)/Fe^(2+)/C_(4)H_(4)O_(6)^(2-)molar ratio. The HPAM degradation efficiency was 90%, and the chemical oxygen demand removal efficiency was 85%. HPAM could be degraded into a compound with a lower molecular weight, but it was difficult to achieve complete mineralization to CO_(2). The presence of intermediate products hindered further oxidation in the Fenton process.
基金financially supported by the National Natural Science Foundation of China(No.51764022)the Fok Ying Tong Education Foundation(No.161046)+3 种基金the China Postdoctoral Science Foundation(No.2020M673551XB)the Fundamental Research Funds for Central UniversitiesChina(No.2020XJHH04)the Yueqi Outstanding Scholar Award of China University of Mining and Technology(Beijing)。
文摘Ilmenite is an essential mineral for the extraction of titanium.Conventional physical separation methods have difficulty recovering fine ilmenite,and dressing plants have begun applying flotation to recover ilmenite.The interaction of reagent groups with Ti and Fe sites on the ilmenite surface dramatically influences the ilmenite flotation.However,the investigation on Fe sites has received more attention because the activity of Ti is lower than that of Fe.For the activators on ilmenite flotation,most are metal ions but typically lead ions.The metal ions of activators promote ilmenite flotation by increasing the active sites on the ilmenite surface.Combined reagents have a better selective separation of ilmenite than single reagents due to their synergistic effect.Combining the lead ion(Pb^(2+))and the benzyl hydroxamic acid(BHA)into a Pb-BHA complex has a marked effect on ilmenite flotation,which puts forward a new idea of developing combined reagents for ilmenite flotation.This review considers reagent types and action mechanisms in ilmenite flotation.On the basis of the analysis of previous research,a brief future outlook of reagent types and action mechanisms in ilmenite flotation is also proposed in this study.
文摘Na2SiO3 and Na2SeO3 were chosen as stable reagents of alkaline thiourea solution substituting Na2SO3, according to the structure-property relationship between the stability of alkaline thiourea and the structure of thiourea and sulfite ion, and the effect of the stable reagents on stability of alkaline thiourea was investigated. The results show that contrary to Na2SeO3, Na2SO3 and Na2SiO3 affect the stability of alkaline thiourea solution remarkably. The stable effect of Na2SiO3 on alkaline thiourea is obviously better than that of Na2SO3. The stable reagents Na2SO3 and Na2SiO3 decrease the decomposition rate of alkaline thiourea solution greatly, and the decomposition rate of alkaline thiourea reduces from (72.5%) to (33.8%) with addition of (0.3 mol·L-1) Na2SiO3. Dissolution currents of gold in the alkaline thiourea solution containing Na2SO3 and Na2SiO3 are (2.0) (mA·cm-2) and (3.5) (mA·cm-2) at the potential of 0.42 V, respectively, and Na2SO3 is consumed excessively due to the oxidation reaction of Na2SO3 occurring in the studied potential range. Na2SiO3 is an efficient stable reagent of alkaline thiourea solution, and gold dissolution is accelerated much more obviously by Na2SiO3 than by Na2SO3.
文摘Substituted PhMgX and PhTi(OCHMe2)4MgX react with 3,5-O-isopropylidene-L-glucurono-γ-lactone 4 to give tetrads 5a-e and its stereoisomers 6a-e Tetrads 5a-e are the important intermediates in the synthesis of howiinol Al and its derivatives. The stereoselectivities of substituted PhTi(OCHMe2)4Mg (5a-e:6a-e ratio, 68-72:32-28) were better than those of substituted PhMgX(33-64:67-36) in the reaction. The effects of different substitUted groups and positions (p-Me, m-Me, o-MeO, p-Cl) of the phenyl ring on their stereoselectivies were not significant.
文摘An environmentally benign and practical preparation method for the Vilsmeier-Haack reagent (VH) has been developed by using phthaloyl dichloride with DMF in toluene or 2-chlorotoluene. Phthalic anhydride as the byproduct was recovered in high yield by simple filtration. Some aromatic acids have been transformed into the corresponding acid chlorides in good yields by employing the isolated VH. Treatment of primary or secondary alcohols with VH gave alkyl formates or alkyl chlorides by depending on the reaction conditions.
基金This work was supported by the NNSFC (No.29672004).
文摘Addition reaction of Grignard’s reagent to 5-methoxy-2(5H)-furanone 1 was accomplished, which provided a new possible route for synthesizing β-alkyl-γ-alkyloxy-γ-butyrolactone. A novel concise method of preparing fused heterocyclic compounds was offered by 1,3-dipolar cycloaddition reaction of silyl nitronates to 1.
文摘Topological method is applied firstly to calculate the group connectivity indexes of some flotation reagents for sulfide minerals and oxide minerals. The study reveals that some properties of flotation reagents, such as group electronegativity, energy criterion, solubility product of chemicals and maximum wavelength of ultraviolet absorbency, have linear correlation with the first order group connectivity index (GCI) of polar group, and the related coefficients are all larger than 0.900. The GCI can be used to characterize the structure of groups, and is a sort of new effective structural parameter to study the quantitative structure activity relationship of flotation reagents.
文摘-This paper first presents a new potassium reagent and efficient enrichment agent for direct recovery of potassium from seawater, i. e. , 1, 2, 4, 5-tetrahydroxybenzen -O, O’ , O", O’’’- tetraacetic acid (TTAH4). The synthetic method of TTAH4, its enrichment behaviour for potassium ion in low concentration solution and seawater, and the chemical structure of its corresponding potassium salt have been investigated. A mechanism which caused the uptake of potassium ion is suggested. Elementary analysis and IR-spectrum determination of the potassium salt proved correct evidence for a polynuclear complex, i. e. , (TTAH3K)n. Thus, the mechanism which caused the uptake of potassium ion may be interpreted in terms of the formation of polynuclear chains as a continual sandwich type coordination complex.
基金supported by the National Natural Science Foundation of China (51974370)the Program of Huxiang Young Talents (2019RS2002)the Innovation and Entrepreneurship Project of Hunan Province, China (Grant No.2018GK5026)。
文摘Lithium ion capacitors(LICs)have been widely used as energy storage devices due to their high energy density and high power density.For LICs,pre-lithiation of negative electrode is necessary.In this work,we employ a bifunctional Li6CoO4(LCO)as cathodic pre-lithiation reagent to improve the electrochemical performance of LICs.The synthesized LCO exhibited high first charge specific capacity of 721 mAh g-1and extremely low initial coulombic efficiency of 3.19%,providing sufficient Li+ for the pre-lithiation of negative electrode in the first charge.Simultaneously,Li6–xCoOy is generated from LCO during the first charge process,which exhibits pseudocapacitive property and contributes to capacity in form of surface capacitance during subsequent cycles,increasing the capacity of capacitive positive electrode.With the appropriate amounts of addition to the positive side in LICs,this bifunctional prelithiation reagent LCO shows significantly improved the electrochemical performance with the energy density of 78.5 Wh kg-1after 300 cycles between 2.0 and 4.2 V at 250 mA g-1.
文摘Nitration of aromatic Compounds is triggered by Vilsmeier-Haack reagent (DMF/POCl3) or (DMF/SOCl2) in the presence of KNO3 or NaNO2 under conventional and non-conventional conditions. The reactions af- forded corresponding Nitro derivatives in very good yield with high regioselectivity. The results obtained in non-conventional methods (Micro wave irradiation, Grinding, Sonication) are comparable with those ob- tained under conventional conditions, but the reaction times of former conditions are substantially shorter than that of the latter.
文摘The influence of the precipitating reagents and dispersants on the formation of nano-aluminum hydroxide from sodium aluminate solution by chemical precipitation was investigated. The influence of the dispersed seeds on the decomposi-tion process was investigated too. The alkaline aluminate solutions were used as original solutions with a concentration of Al2O3 having 14.78 g/dm3, αk—1.6 and127 g/dm3, αk—1.6. For the precipitation processes there were used follow-ing precipitating reagents—solutions HCl, NaHCO3 and NH4HCO3 with a concentration of 80 g/dm3, dispersants—PEG 6000, (NaPO3)6 and Tween 20. For the decomposition process the dispersed seeds and factories seeds were used. Structural studies of the aluminum hydroxide particles were carried out by means of the electron-probe microanalysis and scanning electron microscopy, and phase composition of products was determined by means of X-ray diffraction analysis. Ammonium bicarbonate and Tween 20 were determined as the optimal precipitating reagent and dispersant, correspondingly, resulting in dispersed aluminum hydroxide, which is used as a seed in the decomposition process. It was established that this product in form of dispersed seed considerably reduces the duration of the decomposition process;the maximal decomposition of solution (73.9%) was observed after injection of dispersеd aluminum hydroxide into solution. The final aluminum hydroxide having 90% of particles less than 100 nanometers was obtained within 7 hours of steady decreasing temperature from 70°C to 48°C.
文摘Avian influenza(AI)is one of the most relevant viruses in the poultry industry.The AI virus(AIV)transmission from birds to human causing severe cases and mortality enhanced the magnitude of AI for public health.Consequently,the AIV diagnosis laboratories should be able to detect and identify endemic,epidemic and seasonal influenza strains and other wildlife influenza subtypes that cross the country’s borders.The development in quality controls in according with international rules comes to improve the performance of tests.With this purpose,the Brazilian Reference Laboratory for Avian Influenza(LANAGRO-SP)established a cooperation with the World Organization for Animal Health(OIE)to produce AIV master seeds,inactivated antigens and antiserum to attend the necessities of Brazil and other South America countries under the high quality control for all test.Seventeen of AIV master seed lots and seventeen of inactivated antigens lots produced reached hemagglutination(HA)titers of 1:512 and 1:256,respectively.In addition,fifteen AIV antiserum lots with hemagglutination inhibition(HI)titers reaching 1:4,096 were obtained.The AIV reference reagents produced and applied in laboratory routine successfully.