The tert-butyl nitrite as a bifunctional reagent mediated radical alkene difunctionalization has emerged as a powerful strategy for synthesis of structurally diverse oxime-containing compounds.However,the phosphorus-c...The tert-butyl nitrite as a bifunctional reagent mediated radical alkene difunctionalization has emerged as a powerful strategy for synthesis of structurally diverse oxime-containing compounds.However,the phosphorus-centered radical initiated transformations remain largely elusive.Herein,a visible-lightinduced radical phosphinoyloximation of alkenes with secondary phosphine oxides and tert-butyl nitrite has been developed under photocatalyst-and metal-free conditions.This protocol features mild conditions,broad substrate scope,good functional tolerance,and operational simplicity,yielding a diverse array ofα-phosphinoyl oximes in moderate to good yields with high stereoselectivities.The photomediated homolytic cleavage of O–NO bond of tert-butyl nitrite generates the reactive tert-butoxyl radical and persistent NO radical to act as both HAT reagent and the source of oximes.展开更多
An innovative green process of producing ε-caprolactam was proposed by integrating ammoximation and Beckmann rearrangement effectively. As a first part of the new process, TS-1 molecular sieve-catalyzed synthesis of ...An innovative green process of producing ε-caprolactam was proposed by integrating ammoximation and Beckmann rearrangement effectively. As a first part of the new process, TS-1 molecular sieve-catalyzed synthesis of cyclohexanone oxime from cyclohexanone, ammonia and hydrogen peroxide was carried out in a batch plant. Cyclohexane was used as the solvent in the three-phase reaction system. The influences of essential process parameters on ammoximation were investigated. Under the reaction conditions as catalyst content of 2.5% (by mass); H 2 O 2 /yclohexanone molar ratio of 1.10; NH 3 /cyclohexanone molar ratio of 2.20; reaction temperature of 343 K; reaction time of 5 h, high conversion of cyclohexanone and selectivity to oxime (both>99%) were obtained. Thus, the three-phase ammoximation process showed equal catalytic activity as TS-1 but much more convenient and simpler for the separation of catalyst in comparison to the industrial two-phase system with t-butanol used as solvent.展开更多
Deoximation reaction is one of the most important transformations in organic synthesis and for fine chemical production.Since oximes are easily synthesized from carbonyl compounds and are stable compounds,this reactio...Deoximation reaction is one of the most important transformations in organic synthesis and for fine chemical production.Since oximes are easily synthesized from carbonyl compounds and are stable compounds,this reaction can be used for protection-deprotection,purification,and characterization of carbonyl compounds in organic synthesis,especially for the synthesis of medicines as well as the natural products.Moreover,because many oximes can be synthesized from non-carbonyl starting materials,the deoximation reaction is also widely used in the production of many carbonyl-contained fine chemicals.Deoximation methods by using stoichiometric reagents are mature and can produce the related carbonyl products in very high yield with broad substrate application scopes.But for environment-protection consideration as well as the production cost controlling purpose in fine chemical industry,developing catalytic deoximation methods is the trend of the field and there are a series of references on this topic in recent years.This short review summarized recent advances on the development of deoximation methods from stoichiometric reaction to catalytic reaction and the mechanisms of some important transformations were discussed in detail for reader reference.展开更多
An intrinsic kinetics of cyclohexanone ammoximation in the liquid phase over titanium silicate molecular sieves is investigated in an isothermal slurry reactor at different initial reactant concentrations, catalyst lo...An intrinsic kinetics of cyclohexanone ammoximation in the liquid phase over titanium silicate molecular sieves is investigated in an isothermal slurry reactor at different initial reactant concentrations, catalyst loading, and reaction temperature. The rate equations are developed by analyzing data of kinetic measurements. More than 10 side reactions were found. H2O2 decomposition reaction must be considered and other side reactions can be neglected in the kinetic modeling. The predicted values of reaction rates based on the kinetic models are almost consistent with experimental ones. The models have guidance to the selection of reactor types and they are useful to the design and operation of reactor used.展开更多
Oximes of ketones and aldehydes are efficiently converted to the corresponding carbonyl compounds, using a combination of NaHSO4.H20 and paraformaldehyde in good to excellent yields under solid state conditions at roo...Oximes of ketones and aldehydes are efficiently converted to the corresponding carbonyl compounds, using a combination of NaHSO4.H20 and paraformaldehyde in good to excellent yields under solid state conditions at room temperature for 10 minutes.展开更多
Microwave-assisted reactions are an environmentally friendly approach for synthesizing organic compounds. In this study, oximation of acetylferrocene and acetophenone was conducted under both microwave irradiation and...Microwave-assisted reactions are an environmentally friendly approach for synthesizing organic compounds. In this study, oximation of acetylferrocene and acetophenone was conducted under both microwave irradiation and conventional heating conditions. Acetylferrocene and acetophenone were subjected to oximation under the two conditions in various solvent mixtures, and the extent of conversion was determined by </span><sup><span style="font-family:Verdana;">1</span></sup><span style="font-family:Verdana;">H nuclear magnetic resonance spectroscopy. Microwave irradiation was found to accelerate the rate of oximation of both acetylferrocene and acetophenone. Acceleration of the reaction under microwave irradiation was attributed to the efficient absorption of microwaves by the ferrocene nucleus.展开更多
Deoximation in metal chloride ionic liquids based on 1-alkyl-3-methylimidazolium and triethylene ammonium cations, such as AmimBr（Cl）-MClx （A=ethyl, butyl, benzyl; M=Al, Fe, Cu, Sn and Zn; x=2, 3） and Et3NHCl-FeCl...Deoximation in metal chloride ionic liquids based on 1-alkyl-3-methylimidazolium and triethylene ammonium cations, such as AmimBr（Cl）-MClx （A=ethyl, butyl, benzyl; M=Al, Fe, Cu, Sn and Zn; x=2, 3） and Et3NHCl-FeCl3 were investigated under mild conditions. Ferrate chloride ionic liquid was proved to be an effective catalyst for deoximation of cyclohexanone oxime, exhibiting high conversion of oximes and selectivity to cyclo- hexanone. Good performance for the deoximation of other oximes such as salicylald oxime, acetone oxime, benzo- phenone oxime, 4-nitrobenzald oxime, acetophenone oxime, 2-chlorobenzaldehyde oxime, Acetald oxime, 2-butanone oxime and （1R）-camphor oxime was also achieved with bmimBr-FeCl3 as catalyst and solvent. The de- oximation was determined to carry out via acid-catalytic hydrolysis and the reaction mechanism was proposed.展开更多
Cyclohexanone oxime serves as a crucial intermediate in the synthesis of caprolactam,which is an essential precursor for manufacturing nylonfibers,high-performance engineering plastics,and specialized plasticfilms.Cat...Cyclohexanone oxime serves as a crucial intermediate in the synthesis of caprolactam,which is an essential precursor for manufacturing nylonfibers,high-performance engineering plastics,and specialized plasticfilms.Catalytic hydrogenation of nitrocyclohexane to cyclohexanone oxime has been documented to be an atom-economical,green and environmentally friendly process.In this review,wefirst introduce the current design rules of catalysts for catalytic hydrogenation of nitrocyclohexane in terms of both active metals and supports.Secondly,we discuss the influence of solvent effects on the cyclohexanone oxime from the nitrocyclohexane conversion.In addition,we concisely discuss typically proposed reaction pathways for the hydrogenation of nitrocyclohexane to produce cyclohexanone oxime.Finally,we provide our perspectives on some issues for catalytic conversion of nitrocyclohexane to cyclohexanone oxime in the future.展开更多
As one of the most essential components in photocuring system,photoinitiators(PIs)exert a crucial influence on the properties of the cured product.However,commercially available PIs encounter challenges in simultaneou...As one of the most essential components in photocuring system,photoinitiators(PIs)exert a crucial influence on the properties of the cured product.However,commercially available PIs encounter challenges in simultaneously achieving efficient photoinitiation performance and excellent light absorption properties,significantly limiting their applications in various fields.Here,two bis-chalcones and four corresponding oxime esters(OXEs)were designed and synthesized as highly efficient PIs.Featuring a structure comprising bis-chalcone and two diphenyl sulfides,the conjugated systems in these compounds enhance their light-absorption properties in near-ultraviolet and visible region,effectively.Both the frontier molecular orbital simulations and excited state calculations suggest the contribution of sulfur atoms to electron delocalization and the formation of conjugated structure.Due to the high reactivity of the N–O bond in OXE moiety,the four OXEs exhibit exceptional free radical photoinitiating ability in commercial acrylic monomers/oligomers with LED@365nm as light source.Notably,one of them demonstrates superior performance in the photoinitiation of multifunctional crosslinker,achieving more than 70%conversion within 3 s,coupled with outstanding absorption at 365 nm.These chalcone-based OXEs are considered to exert significant potential in the realm of free radical photocuring.展开更多
To develop new environmentally friendly fungicides,we designed and synthesized a novel series of D/Lconfigured camphor oxime ester derivatives based on the natural product camphor as a lead compound.We investigated th...To develop new environmentally friendly fungicides,we designed and synthesized a novel series of D/Lconfigured camphor oxime ester derivatives based on the natural product camphor as a lead compound.We investigated the in vitro antifungal activity of these compounds against six common plant pathogenic fungi.Among them,compounds B1-6,B1-17 and B2-6 displayed great in vitro activity against Rhizoctonia solani with EC50 values of 7.28,4.64,and 7.62μg/mL.The HOMO and LUMO calculations indicated that strong electronwithdrawing halogen elements exhibit better activity compared to electron-donating alkyl groups.Preliminary mechanistic studies,using SEM and TEM,indicated that compound B1-17 induced disordered entanglement of hyphae,shrinkage of hyphal surfaces,and vacuole swelling and rupture,which disrupted normal hyphal growth.Additionally,compound B1-17 induced the production and accumulation of ROS,disrupted MMP,and effectively inhibited the germination and formation of sclerotia in Rhizoctonia solani.These compounds hold potential as new antifungal agents for further research.展开更多
A variety of aldoximes and ketoximes were oxidized to corresponding aldehydes and ketones by nitric oxide in the presence of oxygen. A presumed mechanism was suggested.
The liquid phase Beckmann rearrangement of cyclohexanone oxime (CHO) using fuming sulfuric acid as a catalyst is a traditional method for preparing ε-caprolactam (CPL). This process has drawbacks, such as environment...The liquid phase Beckmann rearrangement of cyclohexanone oxime (CHO) using fuming sulfuric acid as a catalyst is a traditional method for preparing ε-caprolactam (CPL). This process has drawbacks, such as environmental pollution, corrosion of equipment, and low added value of by-product ammonium sulfate. This article designed and prepared a green silica gel-supported trifluoromethanesulfonic acid catalyst for the liquid-phase Beckmann rearrangement of CHO to prepare (CPL). The influencing factors of catalyst preparation and the optimal reaction conditions for Beckmann rearrangement were investigated. It was found that the optimal conditions for catalyst preparation were as follows: raw material silica gel:trifluoromethanesulfonic acid = 1:0.2 (mass ratio), room temperature, stirring time of 2.5 hours, and solvent of acetonitrile, silica gel mesh size is 100 - 200. The optimal reaction conditions for Beckmann rearrangement are CHO: catalyst = 1:2 (mass ratio), temperature of 130˚C, solvent of benzonitrile, volume of 30 mL/g CHO, and reaction time of 4 hours. Under the above conditions, the conversion of CHO is 90%, and the selectivity of CPL is 90%.展开更多
Caprolactam, which is mainly produced via the Beckmann rearrangement reaction, is an important chemical material. The strict specifications of caprolactam products make the refining process of caprolactam extremely im...Caprolactam, which is mainly produced via the Beckmann rearrangement reaction, is an important chemical material. The strict specifications of caprolactam products make the refining process of caprolactam extremely important. According to the different rearrangement process, the refining process of caprolactam is also different. The main refining sequence of liquid phase rearrangement products includes extraction, ion exchange, hydrogenation, and distillation. The refining process of gas phase rearrangement products is conducted mainly through distillation, crystallization, and hydrogenation. In this paper, the research progress of caprolactam refining technology will be summarized according to different rearrangement reaction processes, which will provide a reference for the selection of appropriate caprolactam refining process.展开更多
A wide variety of aldoximes and ketoximes were regenerated to corresponding carbonyl compounds with Al（NO3）3·9H2O in presence of catalytic amounts of NaBr in CH2Cl2 at room temperature.
The c-Jun N-terminal kinase （JNK） is involved in a variety of important cellular processes and aberrant JNK activity is associated with many human diseases.The ligand-based and receptor-based alignment rules were us...The c-Jun N-terminal kinase （JNK） is involved in a variety of important cellular processes and aberrant JNK activity is associated with many human diseases.The ligand-based and receptor-based alignment rules were used to build 3D-QSAR models for a series of N-benzyl isatin oximes JNK inhibitors. The best models were obtained for the receptor-based alignment with CoMSIA combining steric （S）, electrostatic （E）, and hydrogen bond donor （D） and hydrogen bond acceptor （A） fields （q2 = 0.759, r2 = 0.966, r2 pred = 0.703）. Based on the contour maps of RB CoMSIA model, some key structural factors responsible for inhibitory activity were investigated. Large groups at N-substituent or R6 position are preferred to interact with hydrophobic residues Ile70, Asp150, Ala151, Asn152 and Ser193. Electron-donating or hydrogen bond donor groups on the isatin ring would form polar and hydrogen bond with the negative-charged residue Glu147. In addition, electron-withdrawing groups or hydrogen bond acceptor group near the N-substituent would enhance inhibitory activity. The results are in good accordance and complementary to each other. The developed models could provide guidance in the rational design of more potent and selective JNK inhibitors.展开更多
A novel collector 1-(2-hydroxyphenyl)hex-2-en-1-one oxime(HPHO)was synthesized from 2-hydroxy acetophenone and butyraldehyde.Its flotation performance and adsorption mechanism to malachite were investigated by flotati...A novel collector 1-(2-hydroxyphenyl)hex-2-en-1-one oxime(HPHO)was synthesized from 2-hydroxy acetophenone and butyraldehyde.Its flotation performance and adsorption mechanism to malachite were investigated by flotation test,zeta potential,Fourier transform infrared(FTIR)and X-ray photoelectron spectroscopy(XPS)analysis techniques.Compared with benzohydroxamic acid(BA),1-(2-hydroxyphenyl)ethan-1-one oxime(HPEO)and sodium isobutyl xanthate(SIBX),HPHO exhibited excellent collecting power to malachite without additional reagents,such as Na2S regulator and methyl isobutyl carbinol(MIBC)frother.Results of zeta potential indicated that HPHO was coated on malachite surfaces through a chemisorption process.FTIR and XPS data gave clear evidence for the formation of Cu−oxime complex on malachite surfaces after HPHO adsorption through the linkage between C=C,—OH,N—OH group and Cu species.展开更多
A series of new pyrazole oximes bearing substituted thiazole ring were designed and prepared. The structures of the title compounds were identified by spectral analyses, The results of primary bioassay indicated that ...A series of new pyrazole oximes bearing substituted thiazole ring were designed and prepared. The structures of the title compounds were identified by spectral analyses, The results of primary bioassay indicated that some targeted compounds exhibited promising insecticidal activity besides acaricidal activity, particularly; compounds 8c and 8d were more potent against Tetranychus cinnabarinus and Plutella xylostella than other analogues.展开更多
基金the financial support from the National Natural Science Foundation of China(Nos.22201265,22201264)the China Postdoctoral Science Foundation(Nos.2022M710133,2022TQ0287)。
文摘The tert-butyl nitrite as a bifunctional reagent mediated radical alkene difunctionalization has emerged as a powerful strategy for synthesis of structurally diverse oxime-containing compounds.However,the phosphorus-centered radical initiated transformations remain largely elusive.Herein,a visible-lightinduced radical phosphinoyloximation of alkenes with secondary phosphine oxides and tert-butyl nitrite has been developed under photocatalyst-and metal-free conditions.This protocol features mild conditions,broad substrate scope,good functional tolerance,and operational simplicity,yielding a diverse array ofα-phosphinoyl oximes in moderate to good yields with high stereoselectivities.The photomediated homolytic cleavage of O–NO bond of tert-butyl nitrite generates the reactive tert-butoxyl radical and persistent NO radical to act as both HAT reagent and the source of oximes.
基金Supported by the National Natural Science Foundation of China and Sinopec (20736009)
文摘An innovative green process of producing ε-caprolactam was proposed by integrating ammoximation and Beckmann rearrangement effectively. As a first part of the new process, TS-1 molecular sieve-catalyzed synthesis of cyclohexanone oxime from cyclohexanone, ammonia and hydrogen peroxide was carried out in a batch plant. Cyclohexane was used as the solvent in the three-phase reaction system. The influences of essential process parameters on ammoximation were investigated. Under the reaction conditions as catalyst content of 2.5% (by mass); H 2 O 2 /yclohexanone molar ratio of 1.10; NH 3 /cyclohexanone molar ratio of 2.20; reaction temperature of 343 K; reaction time of 5 h, high conversion of cyclohexanone and selectivity to oxime (both>99%) were obtained. Thus, the three-phase ammoximation process showed equal catalytic activity as TS-1 but much more convenient and simpler for the separation of catalyst in comparison to the industrial two-phase system with t-butanol used as solvent.
基金supported by National Key Research and Development Program of China (No. 2018YFD0200100)Natural Science Foundation of Guangling College (Key Project: No. ZKZD17005+4 种基金 major special project: No. ZKZZ18001)Natural Science Foundation of Jiangsu Province (No. BK20181449)Jiangsu Provincial Six Talent Peaks Project (No. XCL-090)Opening Foundation of the Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University (No. 2016GDGP0104)Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)
文摘Deoximation reaction is one of the most important transformations in organic synthesis and for fine chemical production.Since oximes are easily synthesized from carbonyl compounds and are stable compounds,this reaction can be used for protection-deprotection,purification,and characterization of carbonyl compounds in organic synthesis,especially for the synthesis of medicines as well as the natural products.Moreover,because many oximes can be synthesized from non-carbonyl starting materials,the deoximation reaction is also widely used in the production of many carbonyl-contained fine chemicals.Deoximation methods by using stoichiometric reagents are mature and can produce the related carbonyl products in very high yield with broad substrate application scopes.But for environment-protection consideration as well as the production cost controlling purpose in fine chemical industry,developing catalytic deoximation methods is the trend of the field and there are a series of references on this topic in recent years.This short review summarized recent advances on the development of deoximation methods from stoichiometric reaction to catalytic reaction and the mechanisms of some important transformations were discussed in detail for reader reference.
文摘An intrinsic kinetics of cyclohexanone ammoximation in the liquid phase over titanium silicate molecular sieves is investigated in an isothermal slurry reactor at different initial reactant concentrations, catalyst loading, and reaction temperature. The rate equations are developed by analyzing data of kinetic measurements. More than 10 side reactions were found. H2O2 decomposition reaction must be considered and other side reactions can be neglected in the kinetic modeling. The predicted values of reaction rates based on the kinetic models are almost consistent with experimental ones. The models have guidance to the selection of reactor types and they are useful to the design and operation of reactor used.
文摘Oximes of ketones and aldehydes are efficiently converted to the corresponding carbonyl compounds, using a combination of NaHSO4.H20 and paraformaldehyde in good to excellent yields under solid state conditions at room temperature for 10 minutes.
文摘Microwave-assisted reactions are an environmentally friendly approach for synthesizing organic compounds. In this study, oximation of acetylferrocene and acetophenone was conducted under both microwave irradiation and conventional heating conditions. Acetylferrocene and acetophenone were subjected to oximation under the two conditions in various solvent mixtures, and the extent of conversion was determined by </span><sup><span style="font-family:Verdana;">1</span></sup><span style="font-family:Verdana;">H nuclear magnetic resonance spectroscopy. Microwave irradiation was found to accelerate the rate of oximation of both acetylferrocene and acetophenone. Acceleration of the reaction under microwave irradiation was attributed to the efficient absorption of microwaves by the ferrocene nucleus.
基金Project supported by the Natural Science Foundation of Heilongjiang Province, China （Nos. ZD200820-01 and B200814）.
文摘Deoximation in metal chloride ionic liquids based on 1-alkyl-3-methylimidazolium and triethylene ammonium cations, such as AmimBr（Cl）-MClx （A=ethyl, butyl, benzyl; M=Al, Fe, Cu, Sn and Zn; x=2, 3） and Et3NHCl-FeCl3 were investigated under mild conditions. Ferrate chloride ionic liquid was proved to be an effective catalyst for deoximation of cyclohexanone oxime, exhibiting high conversion of oximes and selectivity to cyclo- hexanone. Good performance for the deoximation of other oximes such as salicylald oxime, acetone oxime, benzo- phenone oxime, 4-nitrobenzald oxime, acetophenone oxime, 2-chlorobenzaldehyde oxime, Acetald oxime, 2-butanone oxime and （1R）-camphor oxime was also achieved with bmimBr-FeCl3 as catalyst and solvent. The de- oximation was determined to carry out via acid-catalytic hydrolysis and the reaction mechanism was proposed.
基金financial support from the National Natural Science Foundation of China(22125202,92461312,U24A20487,92361201)Natural Science Foundation of Jiangsu Province(BK20220033).
文摘Cyclohexanone oxime serves as a crucial intermediate in the synthesis of caprolactam,which is an essential precursor for manufacturing nylonfibers,high-performance engineering plastics,and specialized plasticfilms.Catalytic hydrogenation of nitrocyclohexane to cyclohexanone oxime has been documented to be an atom-economical,green and environmentally friendly process.In this review,wefirst introduce the current design rules of catalysts for catalytic hydrogenation of nitrocyclohexane in terms of both active metals and supports.Secondly,we discuss the influence of solvent effects on the cyclohexanone oxime from the nitrocyclohexane conversion.In addition,we concisely discuss typically proposed reaction pathways for the hydrogenation of nitrocyclohexane to produce cyclohexanone oxime.Finally,we provide our perspectives on some issues for catalytic conversion of nitrocyclohexane to cyclohexanone oxime in the future.
基金National Nature Science Foundation of China(Nos.52025032,52103144 and 523B2026)for their financial supportsupported by the Postdoctoral Fellowship Program of China Postdoctoral Science Foundation(No.GZC20231544)。
文摘As one of the most essential components in photocuring system,photoinitiators(PIs)exert a crucial influence on the properties of the cured product.However,commercially available PIs encounter challenges in simultaneously achieving efficient photoinitiation performance and excellent light absorption properties,significantly limiting their applications in various fields.Here,two bis-chalcones and four corresponding oxime esters(OXEs)were designed and synthesized as highly efficient PIs.Featuring a structure comprising bis-chalcone and two diphenyl sulfides,the conjugated systems in these compounds enhance their light-absorption properties in near-ultraviolet and visible region,effectively.Both the frontier molecular orbital simulations and excited state calculations suggest the contribution of sulfur atoms to electron delocalization and the formation of conjugated structure.Due to the high reactivity of the N–O bond in OXE moiety,the four OXEs exhibit exceptional free radical photoinitiating ability in commercial acrylic monomers/oligomers with LED@365nm as light source.Notably,one of them demonstrates superior performance in the photoinitiation of multifunctional crosslinker,achieving more than 70%conversion within 3 s,coupled with outstanding absorption at 365 nm.These chalcone-based OXEs are considered to exert significant potential in the realm of free radical photocuring.
基金the Fundamental Research Funds for the Central Universities(KYCYXT2022011,KJYQ2024014)the National Key Research and Development Program of China(2021YFD1700102)for the generous financial support for our programs.
文摘To develop new environmentally friendly fungicides,we designed and synthesized a novel series of D/Lconfigured camphor oxime ester derivatives based on the natural product camphor as a lead compound.We investigated the in vitro antifungal activity of these compounds against six common plant pathogenic fungi.Among them,compounds B1-6,B1-17 and B2-6 displayed great in vitro activity against Rhizoctonia solani with EC50 values of 7.28,4.64,and 7.62μg/mL.The HOMO and LUMO calculations indicated that strong electronwithdrawing halogen elements exhibit better activity compared to electron-donating alkyl groups.Preliminary mechanistic studies,using SEM and TEM,indicated that compound B1-17 induced disordered entanglement of hyphae,shrinkage of hyphal surfaces,and vacuole swelling and rupture,which disrupted normal hyphal growth.Additionally,compound B1-17 induced the production and accumulation of ROS,disrupted MMP,and effectively inhibited the germination and formation of sclerotia in Rhizoctonia solani.These compounds hold potential as new antifungal agents for further research.
基金Project supported by the National Natural Science Foundation of China (No. 2967201)the Natural Science Foundation of Gansu Province
文摘A variety of aldoximes and ketoximes were oxidized to corresponding aldehydes and ketones by nitric oxide in the presence of oxygen. A presumed mechanism was suggested.
文摘The liquid phase Beckmann rearrangement of cyclohexanone oxime (CHO) using fuming sulfuric acid as a catalyst is a traditional method for preparing ε-caprolactam (CPL). This process has drawbacks, such as environmental pollution, corrosion of equipment, and low added value of by-product ammonium sulfate. This article designed and prepared a green silica gel-supported trifluoromethanesulfonic acid catalyst for the liquid-phase Beckmann rearrangement of CHO to prepare (CPL). The influencing factors of catalyst preparation and the optimal reaction conditions for Beckmann rearrangement were investigated. It was found that the optimal conditions for catalyst preparation were as follows: raw material silica gel:trifluoromethanesulfonic acid = 1:0.2 (mass ratio), room temperature, stirring time of 2.5 hours, and solvent of acetonitrile, silica gel mesh size is 100 - 200. The optimal reaction conditions for Beckmann rearrangement are CHO: catalyst = 1:2 (mass ratio), temperature of 130˚C, solvent of benzonitrile, volume of 30 mL/g CHO, and reaction time of 4 hours. Under the above conditions, the conversion of CHO is 90%, and the selectivity of CPL is 90%.
文摘Caprolactam, which is mainly produced via the Beckmann rearrangement reaction, is an important chemical material. The strict specifications of caprolactam products make the refining process of caprolactam extremely important. According to the different rearrangement process, the refining process of caprolactam is also different. The main refining sequence of liquid phase rearrangement products includes extraction, ion exchange, hydrogenation, and distillation. The refining process of gas phase rearrangement products is conducted mainly through distillation, crystallization, and hydrogenation. In this paper, the research progress of caprolactam refining technology will be summarized according to different rearrangement reaction processes, which will provide a reference for the selection of appropriate caprolactam refining process.
基金support for this work by the research facilities of Ilam University
文摘A wide variety of aldoximes and ketoximes were regenerated to corresponding carbonyl compounds with Al（NO3）3·9H2O in presence of catalytic amounts of NaBr in CH2Cl2 at room temperature.
基金supported by the Beijing Natural Science Foundation(Grant No.2123062)Research Fund for the Doctoral Program of Higher Education of China(Grant No.20121103120008)Science and Tech-nology Foundation of Beijing University of Technology(Grant No.ykj-2012-8725)
文摘The c-Jun N-terminal kinase （JNK） is involved in a variety of important cellular processes and aberrant JNK activity is associated with many human diseases.The ligand-based and receptor-based alignment rules were used to build 3D-QSAR models for a series of N-benzyl isatin oximes JNK inhibitors. The best models were obtained for the receptor-based alignment with CoMSIA combining steric （S）, electrostatic （E）, and hydrogen bond donor （D） and hydrogen bond acceptor （A） fields （q2 = 0.759, r2 = 0.966, r2 pred = 0.703）. Based on the contour maps of RB CoMSIA model, some key structural factors responsible for inhibitory activity were investigated. Large groups at N-substituent or R6 position are preferred to interact with hydrophobic residues Ile70, Asp150, Ala151, Asn152 and Ser193. Electron-donating or hydrogen bond donor groups on the isatin ring would form polar and hydrogen bond with the negative-charged residue Glu147. In addition, electron-withdrawing groups or hydrogen bond acceptor group near the N-substituent would enhance inhibitory activity. The results are in good accordance and complementary to each other. The developed models could provide guidance in the rational design of more potent and selective JNK inhibitors.
基金Projects(2018GDASCX-0934,2020GDASYL-20200302009)supported by Guangdong Academy of Sciences,China。
文摘A novel collector 1-(2-hydroxyphenyl)hex-2-en-1-one oxime(HPHO)was synthesized from 2-hydroxy acetophenone and butyraldehyde.Its flotation performance and adsorption mechanism to malachite were investigated by flotation test,zeta potential,Fourier transform infrared(FTIR)and X-ray photoelectron spectroscopy(XPS)analysis techniques.Compared with benzohydroxamic acid(BA),1-(2-hydroxyphenyl)ethan-1-one oxime(HPEO)and sodium isobutyl xanthate(SIBX),HPHO exhibited excellent collecting power to malachite without additional reagents,such as Na2S regulator and methyl isobutyl carbinol(MIBC)frother.Results of zeta potential indicated that HPHO was coated on malachite surfaces through a chemisorption process.FTIR and XPS data gave clear evidence for the formation of Cu−oxime complex on malachite surfaces after HPHO adsorption through the linkage between C=C,—OH,N—OH group and Cu species.
基金financial supported by the National Natural Science Foundation of China(No.21202089)China Postdoctoral Science Foundation(No.2013M531145)the Research Foundation of the Six People Peak of Jiangsu Province(No.2013-SWYY-013)
文摘A series of new pyrazole oximes bearing substituted thiazole ring were designed and prepared. The structures of the title compounds were identified by spectral analyses, The results of primary bioassay indicated that some targeted compounds exhibited promising insecticidal activity besides acaricidal activity, particularly; compounds 8c and 8d were more potent against Tetranychus cinnabarinus and Plutella xylostella than other analogues.
