A polyetheramine(PEA)-based Br?nsted-acidic ionic liquid(IL)was firstly prepared and used to promote the alkylation of isobutane with isobutene catalyzed by trifluoromethanesulfonic acid(TfOH).PEA-IL not only can reso...A polyetheramine(PEA)-based Br?nsted-acidic ionic liquid(IL)was firstly prepared and used to promote the alkylation of isobutane with isobutene catalyzed by trifluoromethanesulfonic acid(TfOH).PEA-IL not only can resolve the persistent problem of poor solubility of the volatile and refractory reactants,but also can satisfactorily exhibit the separation of the catalyst from product oil for reuse.The PEA-IL/TfOH catalytic system with an adjustable acidity ensures a high alkylate selectivity.Under the conditions covering a VIL/VTfOH ratio of 10:3,a temperature of 25°C,and a reaction time of 25 min,the C8-product selectivity reaches 86.63%.The PEA-IL/TfOH catalyst can be reused 13 times without a decrease in the catalytic performance.After many operating cycles,the hydrophobic PEA-IL can be easily regenerated by simply adding water.This study provides a green,economic,and highly efficient method for producing high-octane alkylate gasoline.展开更多
This study describes the investigations undertaken at two adjacent properties for known contaminants of concern and for resolution of other “unexpected” contaminant sources. One property is a manufacturing facility ...This study describes the investigations undertaken at two adjacent properties for known contaminants of concern and for resolution of other “unexpected” contaminant sources. One property is a manufacturing facility with impacts from chlorinated solvent compounds releases at the site. During site investigations, benzene was found present in subslab and multi-depth soil vapor probes installed beneath the basement floor of on-site buildings. Additional investigations at the manufacturing site were initiated in response to a recent, unexpected appearance of an unknown light non-aqueous phase liquid (LNAPL) in three on-site perched water zone wells as observed during sequential quarterly monitoring events and in a soil vapor extraction well. The other property is an adjacent petroleum facility that has ongoing LNAPL recovery operations from past releases at its site. A claim was made that benzene vapor at the manufacturing property was solely related to the LNAPL that migrated onto the facility. Multiple lines of evidence, including LNAPL migration pathways and chemical fingerprints, were used to show that the LNAPL was sourced from the petroleum facility. Further, benzene vapor present in subslab vapor probes installed for vapor intrusion purposes was believed to be sourced from the LNAPL and not from historical operations at the manufacturing facility. However, detailed analysis of vapor distributions, the subsurface stratigraphy, and LNAPL characteristics indicate that spills during past operations at the manufacturing facility itself were likely the source of the benzene vapor found in the subslab vapor probes.展开更多
A modified PTC method of preparing tetra-O-alkylated calix[4]arenes is described. Using PEG-400 as phase-transfer catalyst and solid sodium hydrate as a base, full alkylation of calix[4]arenes has been proceeded smoot...A modified PTC method of preparing tetra-O-alkylated calix[4]arenes is described. Using PEG-400 as phase-transfer catalyst and solid sodium hydrate as a base, full alkylation of calix[4]arenes has been proceeded smoothly in toluene at 90°C. The debutylated calix[4]arene can also be fully alkylated by this method.展开更多
Asymmetric migratory hydrofunctionalization of isomeric mixtures of alkenes provides a complementary approach for the selective introduction of a functional group into a remote C(sp3)-H position.However,the simultaneo...Asymmetric migratory hydrofunctionalization of isomeric mixtures of alkenes provides a complementary approach for the selective introduction of a functional group into a remote C(sp3)-H position.However,the simultaneous control of both regio-and enantioselectivity in this migratory process is a challenge.Enantioenrichedα-alkyl-substituted azacycles are key motifs in pharmaceuticals,natural products,and agrochemicals.Here,we report a NiH-catalyzed asymmetric migratory hydroalkylation process for their efficient and selective construction.In this process,easily available isomeric mixtures of N-heterocyclic alkenes can be directly employed as starting materials,convergently delivering a variety of enantioenrichedα-alkylated azacycles with high levels of regio-and enantioselectivity.The synthetic utility of this transformation is demonstrated by the facile synthesis of two bioactive alkaloids,(+)-connine and(R)-pipecoline.The obtained chiralα-alkylated azacycles also readily undergo diverse derivatization,such as deconstructive halogenation and ring contraction.展开更多
Activation of nuclear factor erythroid 2-related factor 2(Nrf2)by Kelch-like ECH-associated protein 1(Keap1)alkylation plays a central role in anti-inflammatory therapy.However,activators of Nrf2 through alkylation of...Activation of nuclear factor erythroid 2-related factor 2(Nrf2)by Kelch-like ECH-associated protein 1(Keap1)alkylation plays a central role in anti-inflammatory therapy.However,activators of Nrf2 through alkylation of Keap1-Kelch domain have not been identified.Deoxynyboquinone(DNQ)is a natural small molecule discovered from marine actinomycetes.The current study was designed to investigate the anti-inflammatory effects and molecular mechanisms of DNQ via alkylation of Keap1.DNQ exhibited significant anti-inflammatory properties both in vitro and in vivo.The pharmacophore responsible for the anti-inflammatory properties of DNQ was determined to be theα,β-unsaturated amides moieties by a chemical reaction between DNQ and N-acetylcysteine.DNQ exerted anti-inflammatory effects through activation of Nrf2/ARE pathway.Keap1 was demonstrated to be the direct target of DNQ and bound with DNQ through conjugate addition reaction involving alkylation.The specific alkylation site of DNQ on Keap1 for Nrf2 activation was elucidated with a synthesized probe in conjunction with liquid chromatography-tandem mass spectrometry.DNQ triggered the ubiquitination and subsequent degradation of Keap1 by alkylation of the cysteine residue 489(Cys489)on Keap1-Kelch domain,ultimately enabling the activation of Nrf2.Our findings revealed that DNQ exhibited potent anti-inflammatory capacity throughα,β-unsaturated amides moieties active group which specifically activated Nrf2 signal pathway via alkylation/ubiquitination of Keap1-Kelch domain,suggesting the potential values of targeting Cys489 on Keap1-Kelch domain by DNQ-like small molecules in inflammatory therapies.展开更多
Two lithium-based ionic liquids(ILs,L-C3N3,and L-P3N3)were synthesized and evaluated as novel lubricant additives for multiply alkylated cyclopentanes(MACs).They were found to be approximately 1.0%soluble in MACs at r...Two lithium-based ionic liquids(ILs,L-C3N3,and L-P3N3)were synthesized and evaluated as novel lubricant additives for multiply alkylated cyclopentanes(MACs).They were found to be approximately 1.0%soluble in MACs at room temperature(RT),whereas traditional ILs,such as 1-ethyl-3-methylimidazolium tetrafluoroborate(L-B102),1-hexyl-3-methylimidazolium hexafluorophosphate(L-P106),and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide(L-F102),could not be dissolved in this base oil.Friction tests indicated that these ILs exhibit excellent friction-reducing and anti-wear properties both at RT and at 100°C.They can improve the tribological properties of MACs at RT to a greater extent than the commonly used lubricant zinc dialkyldithiophosphate(T204),even at a concentration of 0.1%.The load ramp test showed that MACs with L-C3N3 and L-P3N3 also exhibit high load-carrying capabilities.Scanning electron microscope(SEM)and X-ray photoelectron spectrometer(XPS)results indicated that physical adsorption and complex tribochemical reactions occurred between the ILs and metal surfaces during the sliding process,thereby forming a surface protective film that significantly contributed to the excellent tribological properties of the new ILs.展开更多
Catalytic synthesis of m-diethylbenzene(m-DEB)through alkylation of ethylbenzene(EB)may be a promising alternative route in comparison with traditional rectification of mixed DEB,for which the top priority is to devel...Catalytic synthesis of m-diethylbenzene(m-DEB)through alkylation of ethylbenzene(EB)may be a promising alternative route in comparison with traditional rectification of mixed DEB,for which the top priority is to develop efficient and stable heterogeneous catalysts.Here,the spherical nano-ZSM-5 zeolite with abundant intergranular mesoporous is synthesized by the seed-mediated growth method for alkylation of EB with ethanol to produce m-DEB.The results show that the spherical nano-ZSM-5 zeolite exhibits better stability and higher alkylation activity at a lower temperature than those of commercial micropore ZSM-5.And then,the spherical nano-ZSM-5 is further modified by La_(2)O_(3) through acid treatment followed by immersion method.The acid treatment causes nano-ZSM-5 to exhibit the increased pore size but decreased the acid sites,and subsequent La_(2)O_(3) loading reintroduces the weak acid sites.As a result,the HNO_(3)-La_(2)O_(3)-modified catalyst exhibits a slight increase in EB conversion and DEB yield in comparison with unmodified one,and meanwhile,it still maintains high m-DEB selectivity.The catalyst after acid treatment achieves higher catalytic stability besides maintaining the high alkylation activity of EB with ethanol.The present study on the spherical nano-HZSM-5 zeolite and its modification catalyst with excellent alkylation ability provides new insights into the production of mDEB.展开更多
Lignin is the most abundant naturally phenolic biomass,and the synthesis of high-performance renewable fuel from lignin has attracted significant attention.We propose the efficient synthesis of high-density fuels usin...Lignin is the most abundant naturally phenolic biomass,and the synthesis of high-performance renewable fuel from lignin has attracted significant attention.We propose the efficient synthesis of high-density fuels using simulated lignin cracked oil in tandem with hydroalkylation and deoxygenation reactions.First,we investigated the reaction pathway for the hydroalkylation of phenol,which competes with the hydrodeoxygenation form cyclohexane.And then,we investigated the effects of metal catalyst types,the loading amount of metallic,acid dosage,and reactant ratio on the reaction results.The phenol hydroalkylation and hydrodeoxygenation were balanced when 180℃ and 5 MPa H_(2)with the alkanes yield of 95%.By extending the substrate to other lignin-derived phenolics and simulated lignin cracked oil,we obtained the polycyclic alkane fuel with high density of 0.918 g·ml^(-1)and calorific value of41.2 MJ·L^(-1).Besides,the fuel has good low-temperature properties(viscosity of 9.3 mm^(2)·s^(-1)at 20℃ and freezing point below-55℃),which is expected to be used as jet fuel.This work provides a promising way for the easy and green production of high-density fuel directly from real lignin oil.展开更多
Ce-encapsulated Beta zeolite was synthesized by a one-pot hydrothermal method with citric acid complexing Ce in the absence of Na species.Additional citric acid can effectively prevent the deposition of Ce species dur...Ce-encapsulated Beta zeolite was synthesized by a one-pot hydrothermal method with citric acid complexing Ce in the absence of Na species.Additional citric acid can effectively prevent the deposition of Ce species during the hydrothermal synthesis of zeolites,leading to uniform distribution of Ce cluster in the framework of Beta zeolites.Moreover,the sodium-free synthesis system resulted that the Brønsted acid sites were mainly located on the straight channels and external surface of Beta zeolites,improving the utilization of Brønsted acid sites.In addition,Ce encapsulated Beta zeolites showed enhanced activity and robust stability in the alkylation of benzene with 1-dodecene based on the synergistic effect between Ce species and Brønsted acid sites,which pave the way for its practical application in the production of alkylbenzene.展开更多
From the standpoint of chemical structures,the organic backbones of energetic materials can be classified into aromatic rings,nonaromatic rings,and open chains.Although the category of aromatic energetic compounds exh...From the standpoint of chemical structures,the organic backbones of energetic materials can be classified into aromatic rings,nonaromatic rings,and open chains.Although the category of aromatic energetic compounds exhibits several advantages in the regulation of energetic properties,the nonaromatic heterocycles,assembling nitramino explosophores with simple alkyl bridges,still have prevailed in benchmark materials.The methylene bridge plays a pivotal role in the constructions of the classic nonaromatic heterocycle-based energetic compounds,e.g.,hexahydro-1,3,5-trinitro-1,3,5-triazine(RDX)and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine(HMX),whereas ethylene bridge is the core moiety of state-of-the-art explosive 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane(CL-20).In this context,it is of great interest to employ simple and practical bridges to assemble aromatic and nonaromatic nitrogen-rich heterocycles,thereby expanding the structural diversity of energetic materials,e.g.,bridged and fused nitrogen-rich poly-heterocycles.Furthermore,alkyl-bridged poly-heterocycles highlight the potential for the open chain type of energetic materials.In this review,the development of alkyl bridges in linking nitrogen-rich heterocycles is presented,and the perspective of the newly constructed energetic backbones is summarized for the future design of advanced energetic materials.展开更多
To expedite the development of industrial technology for producing 2-alkylanthraquinone,a novel pilot test of alkylation-oxidation technology was conducted.The process mainly included anthracene alkylation,separation ...To expedite the development of industrial technology for producing 2-alkylanthraquinone,a novel pilot test of alkylation-oxidation technology was conducted.The process mainly included anthracene alkylation,separation of anthracene and 2-alkylanthracene,oxidation of 2-alkylanthracene,and product purification.Optimal alkylation conditions yielded a 91.1%conversion of anthracene and a 71.73%selectivity for 2-alkylanthracene.To address the separation problem of anthracene and 2-alkylanthracene,solvent-assisted distillation technology was developed,resulting in a 98.9%purity of 2-alkylanthracene and a 91.82%separation yield.When the molar ratio of H2O_(2) to 2-alkylanthracene was 7:1,a 98.96%conversion of 2-alkylanthracene and a 99.94%selectivity for 2-alkylanthraquinone were achieved.A novel composition of 2-alkylanthraquinone,including 2-tert-butylanthraquinone,2-tert-amylanthraquinone,and 2-hexylanthraquinone,was developed.This composition could be effectively separated and purified through a combination of crystallization and washing processes.The elemental composition of the product met the existing standards,and its hydrogenation performance closely matched that of commercially available 2-tert-amylanthraquinone products.展开更多
Photocatalytic reduction of CO_(2) into fuel represents a promising approach for achieving carbon neutrality,while realizing high selectivity in this process is challenging due to uncontrollable reaction intermediate ...Photocatalytic reduction of CO_(2) into fuel represents a promising approach for achieving carbon neutrality,while realizing high selectivity in this process is challenging due to uncontrollable reaction intermediate and retarded desorption of target products.Engineering the interface microenvironment of catalysts has been proposed as a strategy to exert a significant influence on reaction outcomes,yet it remains a significant challenge.In this study,amino alkylation was successfully integrated into the melem unit of polymeric carbon nitrides(PCN),which could efficiently drive the photocatalytic CO_(2) reduction.Experimental characterization and theoretical calculations revealed that the introduction of amino alkylation lowers the energy barrier for CO_(2) reduction into^(*)COOH intermediate,transforming the adsorption of^(*)COOH intermediate from the endothermic to an exothermic process.Notably,the as-prepared materials demonstrated outstanding performance in photocatalytic CO_(2) reduction,yielding CO_(2)at a rate of 152.8μmol h^(-1) with a high selectivity of 95.4%and a quantum efficiency of 6.6%.展开更多
The biodegradability of three alkylates （2,3-dimethylpentane, 2,4-dimethylpentane and 2,2,4-trimethylpentane） under less agitated aquifer conditions was investigated in this study. All three alkylates biodegraded co...The biodegradability of three alkylates （2,3-dimethylpentane, 2,4-dimethylpentane and 2,2,4-trimethylpentane） under less agitated aquifer conditions was investigated in this study. All three alkylates biodegraded completely under these conditions regardless of the presence or absence of ethanol or benzene, toluene, ethylbenzene, and xylenes （BTEX） in the feed. In the presence of ethanol, alkylates degradation was not inhibited by ethanol. However, alkylates degraded more slowly in the presence of BTEX suggesting competitive inhibition to microbial utilization of alkylates. In the sterile controls, alkylates concentrations remained unchanged throughout the experiments.展开更多
Large-scale production of graphene and sub- sequent sample engineering is the key for fully-realizing the potential applications proposed to this intriguing two-dimensional nanomaterial. Herein, smart graphene dispers...Large-scale production of graphene and sub- sequent sample engineering is the key for fully-realizing the potential applications proposed to this intriguing two-dimensional nanomaterial. Herein, smart graphene dispersions with low defects and thermo-responsive properties can be obtained by liquid phase exfoliation of graphite using an alkylated Percec monodendron （3,4,5-trioctadecy- loxybenzaldehyde, 1） as the stabilizing reagent. By simply changing the temperature, the dispersed graphene and 1 can be detached, leading to the recovery of both components. Besides noncovalent wrapping, the stabilizing reagent 1 can be also covalently attached to graphene through [3＋2] cycloaddition. The covalently functionalized graphene sheets show improved dispersibility in organic solvents compared to the pristine graphene, which opens the door for their applications in various polymer matrixes. The strategy demonstrated here provides a new methodology to get smart graphene dispersions with multiple functions.展开更多
Carbon nanofibers have revolutionized nanotechnology due to their potential applications in emerging frontiers of research and industrial sectors. This can be attributed to their superior properties such as higher mec...Carbon nanofibers have revolutionized nanotechnology due to their potential applications in emerging frontiers of research and industrial sectors. This can be attributed to their superior properties such as higher mechanical strength, unique surface characteristics, and improved adherence that is transmitted into the polymer matrix to form a nanocomposite with improved properties. Polymethyl methacrylate is a common carbon source for the synthesis of carbon nanofibres of its high mechanical strength, thermal stability, and low moisture and water absorbing capacity that allows its products to have several applications. In this work, we report the successful electrospinning of carbon nanofibres from Poly methyl methacrylate and functionalizing the resulting carbon nanofibres. The functionalized carbon nanofibres were analyzed to determine their solubility/dispersion in selected organic solvents, then characterized using Fourier transform infra-red spectroscopy, Raman spectroscopy, scanning electron microscopy combined with Energy dispersive spectroscopy and Thermalgravimetric analysis.展开更多
The alkylation reaction of guanine and N-acetylguanine with model compounds such as isopropyl bromide or 4-heptyl tosylate were studied. The reaction conditions such as temperature, solvent, base, and catalyst were ex...The alkylation reaction of guanine and N-acetylguanine with model compounds such as isopropyl bromide or 4-heptyl tosylate were studied. The reaction conditions such as temperature, solvent, base, and catalyst were examined for their effects on the reaction rate, and the yield and regioselectivity of the coupling reaction. The highest yield was obtained by using DMSO as the solvent. The reaction proceeded in a homogenous manner to give higher yield of 9-N and 7-N substituted product in a mole ratio of 1:1. The ratio could be raised to 2:1 if dibenzo-18-crown-6 was used as a catalyst. Using the above procedure, three carba-DHPG analogues bearing different 1'-C alkyl side chains were synthesized.展开更多
Erratum to Friction 1(3):222-231(2013)DOI 10.1007/s40544‐013‐0019‐x The original version of this article unfortunately contained the incorrect E‐mail address of the corresponding author Mingjin Fan on page 222,ins...Erratum to Friction 1(3):222-231(2013)DOI 10.1007/s40544‐013‐0019‐x The original version of this article unfortunately contained the incorrect E‐mail address of the corresponding author Mingjin Fan on page 222,instead of farmingjin@licp.cus.cn It should read fanmingjin@licp.cas.cn.展开更多
The pyrolysis of cyclohexane,methylcyclohexane,and ethylcyclohexane have been studied behind reflected shock waves at pressures of 5 and10 bar and at temperatures of 930-1550 K for 0.05%fuel diluted by Argon.A single-...The pyrolysis of cyclohexane,methylcyclohexane,and ethylcyclohexane have been studied behind reflected shock waves at pressures of 5 and10 bar and at temperatures of 930-1550 K for 0.05%fuel diluted by Argon.A single-pulse shock tube(SPST)is used to perform the pyrolysis experiments at reaction times varying from 1.65 to 1.74 ms.Major products are obtained and quantified using gas chromatography analysis.A flame ionization detector and a thermal conductivity detector are used for species identification and quantification.Kinetic modeling has been performed using several detailed and lumped chemical kinetic mechanisms.Differences in modeling results among the kinetic models are described.Reaction path analysis and sensitivity analysis are performed to determine the important reactions controlling fuel pyrolysis and their influence on the predicted concentrations of reactant and product species profiles.The present work provides new fundamental knowledge in understating pyrolysis characteristics of cyclohexane compounds and additional data set for detailed kinetic mechanism development.展开更多
Naphthenic base oil is an important lubricating base oil and very scarce in the global petroleum resources.Herein,a series of alkylated tetralin fluids similar to naphthenic base oils were produced by the alkylation o...Naphthenic base oil is an important lubricating base oil and very scarce in the global petroleum resources.Herein,a series of alkylated tetralin fluids similar to naphthenic base oils were produced by the alkylation of tetralin and a-olefins(n-hexene,n-octene,n-decene)with ionic liquid Et_3NHCl/AlCl_(3)as the catalyst,where the applied raw materials are totally derived from the coal chemical industry.The product composition could be controlled by adjusting the feeding ratio of tetralin and olefin.The synthetic fluids were evaluated as lubricating base oils to reveal the structure-property correlations.Their principal physicochemical and tribological properties depend on the chain-length of a-olefins and the number of alkyl groups onto the aromatic rings.Bis-(octyl-or decyl-)alkyl tetralin exhibited good properties in terms of viscosity,thermo-oxidation stability and pour point,as well as friction-reducing and anti-wear performance,showing great potential for producing naphthenic base synthetic oils from coal-based chemicals.展开更多
Synthesizing high-density fuel from lignocellulose can not only achieve green and low-carbon development,but also expand the feedstock source of hydrocarbon fuel.Here,we reported a route of producing high-density fuel...Synthesizing high-density fuel from lignocellulose can not only achieve green and low-carbon development,but also expand the feedstock source of hydrocarbon fuel.Here,we reported a route of producing high-density fuel from lignin oil and hemicellulose derivative cyclopentanol through alkylation and hydrodeoxygenation,HY with SiO_(2)/Al_(2)O_(3) molar ratio of 5.3 was screened as the alkylation catalyst in the reaction of model phenolic compounds and mixtures,and the reaction conditions were optimized to achieve conversion of phenolic compounds higher than 87%and selectivity of bicyclic and tricyclic products higher than 99%.Then two phenolic pools simulating the composition of two typic lignin oils were studied to validate the alkylation and analyze the competition mechanism of phenolic compounds in mixture system.Finally,real lignin oil from depolymerized of beech powder was tested,and notably80%of phenolic monomers in the oil were converted into fuel precursor.After hydrodeoxygenation,the alkylated product was converted to fuel blend with a density of 0.91 g/mL at 20℃and a freezing point lower than-60℃,very promising as high density fuel.This work provides a facile and energyefficient way of synthesizing high-performance jet fuel directly from lignocellulosic derivatives,which decreases processing energy consumption and improve the utilization rate of feedstock.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.21476120,21805158)the Shandong Province Priority Development Plan of China(Nos.2017GGX40107,2019GGX102021)。
文摘A polyetheramine(PEA)-based Br?nsted-acidic ionic liquid(IL)was firstly prepared and used to promote the alkylation of isobutane with isobutene catalyzed by trifluoromethanesulfonic acid(TfOH).PEA-IL not only can resolve the persistent problem of poor solubility of the volatile and refractory reactants,but also can satisfactorily exhibit the separation of the catalyst from product oil for reuse.The PEA-IL/TfOH catalytic system with an adjustable acidity ensures a high alkylate selectivity.Under the conditions covering a VIL/VTfOH ratio of 10:3,a temperature of 25°C,and a reaction time of 25 min,the C8-product selectivity reaches 86.63%.The PEA-IL/TfOH catalyst can be reused 13 times without a decrease in the catalytic performance.After many operating cycles,the hydrophobic PEA-IL can be easily regenerated by simply adding water.This study provides a green,economic,and highly efficient method for producing high-octane alkylate gasoline.
文摘This study describes the investigations undertaken at two adjacent properties for known contaminants of concern and for resolution of other “unexpected” contaminant sources. One property is a manufacturing facility with impacts from chlorinated solvent compounds releases at the site. During site investigations, benzene was found present in subslab and multi-depth soil vapor probes installed beneath the basement floor of on-site buildings. Additional investigations at the manufacturing site were initiated in response to a recent, unexpected appearance of an unknown light non-aqueous phase liquid (LNAPL) in three on-site perched water zone wells as observed during sequential quarterly monitoring events and in a soil vapor extraction well. The other property is an adjacent petroleum facility that has ongoing LNAPL recovery operations from past releases at its site. A claim was made that benzene vapor at the manufacturing property was solely related to the LNAPL that migrated onto the facility. Multiple lines of evidence, including LNAPL migration pathways and chemical fingerprints, were used to show that the LNAPL was sourced from the petroleum facility. Further, benzene vapor present in subslab vapor probes installed for vapor intrusion purposes was believed to be sourced from the LNAPL and not from historical operations at the manufacturing facility. However, detailed analysis of vapor distributions, the subsurface stratigraphy, and LNAPL characteristics indicate that spills during past operations at the manufacturing facility itself were likely the source of the benzene vapor found in the subslab vapor probes.
文摘A modified PTC method of preparing tetra-O-alkylated calix[4]arenes is described. Using PEG-400 as phase-transfer catalyst and solid sodium hydrate as a base, full alkylation of calix[4]arenes has been proceeded smoothly in toluene at 90°C. The debutylated calix[4]arene can also be fully alkylated by this method.
基金the National Key R&D Program of China(grant no.2022YFA1503200)NSFC(grant nos.92156004,22271146,and 22271143)+1 种基金the Open Research Fund of School of Chemistry and Chemical Engineering,Henan Normal University,the Open Research Fund of the Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs,the China Postdoctoral Science Foundation(grant no.2021M701655)the Jiangsu Funding Program for Excellent Postdoctoral Talent(grant no.20220ZB24).
文摘Asymmetric migratory hydrofunctionalization of isomeric mixtures of alkenes provides a complementary approach for the selective introduction of a functional group into a remote C(sp3)-H position.However,the simultaneous control of both regio-and enantioselectivity in this migratory process is a challenge.Enantioenrichedα-alkyl-substituted azacycles are key motifs in pharmaceuticals,natural products,and agrochemicals.Here,we report a NiH-catalyzed asymmetric migratory hydroalkylation process for their efficient and selective construction.In this process,easily available isomeric mixtures of N-heterocyclic alkenes can be directly employed as starting materials,convergently delivering a variety of enantioenrichedα-alkylated azacycles with high levels of regio-and enantioselectivity.The synthetic utility of this transformation is demonstrated by the facile synthesis of two bioactive alkaloids,(+)-connine and(R)-pipecoline.The obtained chiralα-alkylated azacycles also readily undergo diverse derivatization,such as deconstructive halogenation and ring contraction.
基金the Science and Technology Development Fund,Macao SAR(Grant Nos.:No.0159/2020/A3,No.0058/2020/AMJ,No.0096/2019/A2 and SKL-QRCM(UM)-2023-2025)the Research Committee of the University of Macao(Grant No.:MYRG2022-00189-ICMS)+2 种基金the Guangdong Provincial Special Fund for Marine Economic Development Project(Project No.:GDNRC[2021]48)National Natural Science Foundation of China(Grant No.:82260801)K.C.Wong Education Foundation(Grant No.:GJTD-2020-12).
文摘Activation of nuclear factor erythroid 2-related factor 2(Nrf2)by Kelch-like ECH-associated protein 1(Keap1)alkylation plays a central role in anti-inflammatory therapy.However,activators of Nrf2 through alkylation of Keap1-Kelch domain have not been identified.Deoxynyboquinone(DNQ)is a natural small molecule discovered from marine actinomycetes.The current study was designed to investigate the anti-inflammatory effects and molecular mechanisms of DNQ via alkylation of Keap1.DNQ exhibited significant anti-inflammatory properties both in vitro and in vivo.The pharmacophore responsible for the anti-inflammatory properties of DNQ was determined to be theα,β-unsaturated amides moieties by a chemical reaction between DNQ and N-acetylcysteine.DNQ exerted anti-inflammatory effects through activation of Nrf2/ARE pathway.Keap1 was demonstrated to be the direct target of DNQ and bound with DNQ through conjugate addition reaction involving alkylation.The specific alkylation site of DNQ on Keap1 for Nrf2 activation was elucidated with a synthesized probe in conjunction with liquid chromatography-tandem mass spectrometry.DNQ triggered the ubiquitination and subsequent degradation of Keap1 by alkylation of the cysteine residue 489(Cys489)on Keap1-Kelch domain,ultimately enabling the activation of Nrf2.Our findings revealed that DNQ exhibited potent anti-inflammatory capacity throughα,β-unsaturated amides moieties active group which specifically activated Nrf2 signal pathway via alkylation/ubiquitination of Keap1-Kelch domain,suggesting the potential values of targeting Cys489 on Keap1-Kelch domain by DNQ-like small molecules in inflammatory therapies.
基金The National Natural Science Foundation of China(NSFC)(Nos.51105353,51175492,and 21173243)The National Key Basic Research and Development(973)Program of China project(2013CB632300).
文摘Two lithium-based ionic liquids(ILs,L-C3N3,and L-P3N3)were synthesized and evaluated as novel lubricant additives for multiply alkylated cyclopentanes(MACs).They were found to be approximately 1.0%soluble in MACs at room temperature(RT),whereas traditional ILs,such as 1-ethyl-3-methylimidazolium tetrafluoroborate(L-B102),1-hexyl-3-methylimidazolium hexafluorophosphate(L-P106),and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide(L-F102),could not be dissolved in this base oil.Friction tests indicated that these ILs exhibit excellent friction-reducing and anti-wear properties both at RT and at 100°C.They can improve the tribological properties of MACs at RT to a greater extent than the commonly used lubricant zinc dialkyldithiophosphate(T204),even at a concentration of 0.1%.The load ramp test showed that MACs with L-C3N3 and L-P3N3 also exhibit high load-carrying capabilities.Scanning electron microscope(SEM)and X-ray photoelectron spectrometer(XPS)results indicated that physical adsorption and complex tribochemical reactions occurred between the ILs and metal surfaces during the sliding process,thereby forming a surface protective film that significantly contributed to the excellent tribological properties of the new ILs.
基金Research support is from the Service Local Project of the Education Department of Liaoning Province(LJKMZ22021404,LF2019002 and LJKMZ22021423)the“Transformational Technologies for Clean Energy and Demonstration”,Strategic Priority Research Program of the Chinese Academy of Sciences,(XDA 21030500).
文摘Catalytic synthesis of m-diethylbenzene(m-DEB)through alkylation of ethylbenzene(EB)may be a promising alternative route in comparison with traditional rectification of mixed DEB,for which the top priority is to develop efficient and stable heterogeneous catalysts.Here,the spherical nano-ZSM-5 zeolite with abundant intergranular mesoporous is synthesized by the seed-mediated growth method for alkylation of EB with ethanol to produce m-DEB.The results show that the spherical nano-ZSM-5 zeolite exhibits better stability and higher alkylation activity at a lower temperature than those of commercial micropore ZSM-5.And then,the spherical nano-ZSM-5 is further modified by La_(2)O_(3) through acid treatment followed by immersion method.The acid treatment causes nano-ZSM-5 to exhibit the increased pore size but decreased the acid sites,and subsequent La_(2)O_(3) loading reintroduces the weak acid sites.As a result,the HNO_(3)-La_(2)O_(3)-modified catalyst exhibits a slight increase in EB conversion and DEB yield in comparison with unmodified one,and meanwhile,it still maintains high m-DEB selectivity.The catalyst after acid treatment achieves higher catalytic stability besides maintaining the high alkylation activity of EB with ethanol.The present study on the spherical nano-HZSM-5 zeolite and its modification catalyst with excellent alkylation ability provides new insights into the production of mDEB.
基金the support from National Key Research and Development Program of China(2021YFC2104400)the Tianjin Science and Technology Plan Project(21JCQNJC00340)the Haihe Laboratory of Sustainable Chemical Transformations for financial support。
文摘Lignin is the most abundant naturally phenolic biomass,and the synthesis of high-performance renewable fuel from lignin has attracted significant attention.We propose the efficient synthesis of high-density fuels using simulated lignin cracked oil in tandem with hydroalkylation and deoxygenation reactions.First,we investigated the reaction pathway for the hydroalkylation of phenol,which competes with the hydrodeoxygenation form cyclohexane.And then,we investigated the effects of metal catalyst types,the loading amount of metallic,acid dosage,and reactant ratio on the reaction results.The phenol hydroalkylation and hydrodeoxygenation were balanced when 180℃ and 5 MPa H_(2)with the alkanes yield of 95%.By extending the substrate to other lignin-derived phenolics and simulated lignin cracked oil,we obtained the polycyclic alkane fuel with high density of 0.918 g·ml^(-1)and calorific value of41.2 MJ·L^(-1).Besides,the fuel has good low-temperature properties(viscosity of 9.3 mm^(2)·s^(-1)at 20℃ and freezing point below-55℃),which is expected to be used as jet fuel.This work provides a promising way for the easy and green production of high-density fuel directly from real lignin oil.
基金supported by the National Natural Science Foundation of China(22278090,21978055)Natural Science Foundation of Guangdong Province,China(2022A1515012088)the Science and Technology Planning Project of Guangdong Province,China(2022A0505030073,2022A0505030013).
文摘Ce-encapsulated Beta zeolite was synthesized by a one-pot hydrothermal method with citric acid complexing Ce in the absence of Na species.Additional citric acid can effectively prevent the deposition of Ce species during the hydrothermal synthesis of zeolites,leading to uniform distribution of Ce cluster in the framework of Beta zeolites.Moreover,the sodium-free synthesis system resulted that the Brønsted acid sites were mainly located on the straight channels and external surface of Beta zeolites,improving the utilization of Brønsted acid sites.In addition,Ce encapsulated Beta zeolites showed enhanced activity and robust stability in the alkylation of benzene with 1-dodecene based on the synergistic effect between Ce species and Brønsted acid sites,which pave the way for its practical application in the production of alkylbenzene.
基金National Natural Science Foundation of China(Grant Nos.22075023,22205022,and 22235003)to provide fund for conducting experiments。
文摘From the standpoint of chemical structures,the organic backbones of energetic materials can be classified into aromatic rings,nonaromatic rings,and open chains.Although the category of aromatic energetic compounds exhibits several advantages in the regulation of energetic properties,the nonaromatic heterocycles,assembling nitramino explosophores with simple alkyl bridges,still have prevailed in benchmark materials.The methylene bridge plays a pivotal role in the constructions of the classic nonaromatic heterocycle-based energetic compounds,e.g.,hexahydro-1,3,5-trinitro-1,3,5-triazine(RDX)and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine(HMX),whereas ethylene bridge is the core moiety of state-of-the-art explosive 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane(CL-20).In this context,it is of great interest to employ simple and practical bridges to assemble aromatic and nonaromatic nitrogen-rich heterocycles,thereby expanding the structural diversity of energetic materials,e.g.,bridged and fused nitrogen-rich poly-heterocycles.Furthermore,alkyl-bridged poly-heterocycles highlight the potential for the open chain type of energetic materials.In this review,the development of alkyl bridges in linking nitrogen-rich heterocycles is presented,and the perspective of the newly constructed energetic backbones is summarized for the future design of advanced energetic materials.
基金supported by a grant from the National Natural Science Foundation of China(NSFC 22378437)the SINOPEC Excellent Youth Funds(ST22174).
文摘To expedite the development of industrial technology for producing 2-alkylanthraquinone,a novel pilot test of alkylation-oxidation technology was conducted.The process mainly included anthracene alkylation,separation of anthracene and 2-alkylanthracene,oxidation of 2-alkylanthracene,and product purification.Optimal alkylation conditions yielded a 91.1%conversion of anthracene and a 71.73%selectivity for 2-alkylanthracene.To address the separation problem of anthracene and 2-alkylanthracene,solvent-assisted distillation technology was developed,resulting in a 98.9%purity of 2-alkylanthracene and a 91.82%separation yield.When the molar ratio of H2O_(2) to 2-alkylanthracene was 7:1,a 98.96%conversion of 2-alkylanthracene and a 99.94%selectivity for 2-alkylanthraquinone were achieved.A novel composition of 2-alkylanthraquinone,including 2-tert-butylanthraquinone,2-tert-amylanthraquinone,and 2-hexylanthraquinone,was developed.This composition could be effectively separated and purified through a combination of crystallization and washing processes.The elemental composition of the product met the existing standards,and its hydrogenation performance closely matched that of commercially available 2-tert-amylanthraquinone products.
基金financially supported by the National Natural Science Foundation of China(22309032)the Guangdong Basic and Applied Basic Research Foundation(2022A1515011737)+1 种基金the Science and Technology Program of Guangzhou(2023A04J1395)the GDAS’Project of Science and Technology Development(2021GDASYL-20210102010)。
文摘Photocatalytic reduction of CO_(2) into fuel represents a promising approach for achieving carbon neutrality,while realizing high selectivity in this process is challenging due to uncontrollable reaction intermediate and retarded desorption of target products.Engineering the interface microenvironment of catalysts has been proposed as a strategy to exert a significant influence on reaction outcomes,yet it remains a significant challenge.In this study,amino alkylation was successfully integrated into the melem unit of polymeric carbon nitrides(PCN),which could efficiently drive the photocatalytic CO_(2) reduction.Experimental characterization and theoretical calculations revealed that the introduction of amino alkylation lowers the energy barrier for CO_(2) reduction into^(*)COOH intermediate,transforming the adsorption of^(*)COOH intermediate from the endothermic to an exothermic process.Notably,the as-prepared materials demonstrated outstanding performance in photocatalytic CO_(2) reduction,yielding CO_(2)at a rate of 152.8μmol h^(-1) with a high selectivity of 95.4%and a quantum efficiency of 6.6%.
基金supported by the U.S. Environmental Protection Agency (Contract No.68-C-00-159)
文摘The biodegradability of three alkylates （2,3-dimethylpentane, 2,4-dimethylpentane and 2,2,4-trimethylpentane） under less agitated aquifer conditions was investigated in this study. All three alkylates biodegraded completely under these conditions regardless of the presence or absence of ethanol or benzene, toluene, ethylbenzene, and xylenes （BTEX） in the feed. In the presence of ethanol, alkylates degradation was not inhibited by ethanol. However, alkylates degraded more slowly in the presence of BTEX suggesting competitive inhibition to microbial utilization of alkylates. In the sterile controls, alkylates concentrations remained unchanged throughout the experiments.
基金supported by the Hundred Talents Program of Chinese Academy of Sciences(Y20245YBR1)the National Natural Science Foundation of China(21402215 and 61474124)the financial support from Shandong Province Higher Education Science and Technology Program(J16LA01)
文摘Large-scale production of graphene and sub- sequent sample engineering is the key for fully-realizing the potential applications proposed to this intriguing two-dimensional nanomaterial. Herein, smart graphene dispersions with low defects and thermo-responsive properties can be obtained by liquid phase exfoliation of graphite using an alkylated Percec monodendron （3,4,5-trioctadecy- loxybenzaldehyde, 1） as the stabilizing reagent. By simply changing the temperature, the dispersed graphene and 1 can be detached, leading to the recovery of both components. Besides noncovalent wrapping, the stabilizing reagent 1 can be also covalently attached to graphene through [3＋2] cycloaddition. The covalently functionalized graphene sheets show improved dispersibility in organic solvents compared to the pristine graphene, which opens the door for their applications in various polymer matrixes. The strategy demonstrated here provides a new methodology to get smart graphene dispersions with multiple functions.
文摘Carbon nanofibers have revolutionized nanotechnology due to their potential applications in emerging frontiers of research and industrial sectors. This can be attributed to their superior properties such as higher mechanical strength, unique surface characteristics, and improved adherence that is transmitted into the polymer matrix to form a nanocomposite with improved properties. Polymethyl methacrylate is a common carbon source for the synthesis of carbon nanofibres of its high mechanical strength, thermal stability, and low moisture and water absorbing capacity that allows its products to have several applications. In this work, we report the successful electrospinning of carbon nanofibres from Poly methyl methacrylate and functionalizing the resulting carbon nanofibres. The functionalized carbon nanofibres were analyzed to determine their solubility/dispersion in selected organic solvents, then characterized using Fourier transform infra-red spectroscopy, Raman spectroscopy, scanning electron microscopy combined with Energy dispersive spectroscopy and Thermalgravimetric analysis.
文摘The alkylation reaction of guanine and N-acetylguanine with model compounds such as isopropyl bromide or 4-heptyl tosylate were studied. The reaction conditions such as temperature, solvent, base, and catalyst were examined for their effects on the reaction rate, and the yield and regioselectivity of the coupling reaction. The highest yield was obtained by using DMSO as the solvent. The reaction proceeded in a homogenous manner to give higher yield of 9-N and 7-N substituted product in a mole ratio of 1:1. The ratio could be raised to 2:1 if dibenzo-18-crown-6 was used as a catalyst. Using the above procedure, three carba-DHPG analogues bearing different 1'-C alkyl side chains were synthesized.
文摘Erratum to Friction 1(3):222-231(2013)DOI 10.1007/s40544‐013‐0019‐x The original version of this article unfortunately contained the incorrect E‐mail address of the corresponding author Mingjin Fan on page 222,instead of farmingjin@licp.cus.cn It should read fanmingjin@licp.cas.cn.
文摘The pyrolysis of cyclohexane,methylcyclohexane,and ethylcyclohexane have been studied behind reflected shock waves at pressures of 5 and10 bar and at temperatures of 930-1550 K for 0.05%fuel diluted by Argon.A single-pulse shock tube(SPST)is used to perform the pyrolysis experiments at reaction times varying from 1.65 to 1.74 ms.Major products are obtained and quantified using gas chromatography analysis.A flame ionization detector and a thermal conductivity detector are used for species identification and quantification.Kinetic modeling has been performed using several detailed and lumped chemical kinetic mechanisms.Differences in modeling results among the kinetic models are described.Reaction path analysis and sensitivity analysis are performed to determine the important reactions controlling fuel pyrolysis and their influence on the predicted concentrations of reactant and product species profiles.The present work provides new fundamental knowledge in understating pyrolysis characteristics of cyclohexane compounds and additional data set for detailed kinetic mechanism development.
基金financially supported by the National Natural Science Foundation of China(U1910202,21978194,22078219 and 22072173)the Fund for Shanxi“1331 Project”the Key Research and Development Program of Shanxi Province(202102090301005)。
文摘Naphthenic base oil is an important lubricating base oil and very scarce in the global petroleum resources.Herein,a series of alkylated tetralin fluids similar to naphthenic base oils were produced by the alkylation of tetralin and a-olefins(n-hexene,n-octene,n-decene)with ionic liquid Et_3NHCl/AlCl_(3)as the catalyst,where the applied raw materials are totally derived from the coal chemical industry.The product composition could be controlled by adjusting the feeding ratio of tetralin and olefin.The synthetic fluids were evaluated as lubricating base oils to reveal the structure-property correlations.Their principal physicochemical and tribological properties depend on the chain-length of a-olefins and the number of alkyl groups onto the aromatic rings.Bis-(octyl-or decyl-)alkyl tetralin exhibited good properties in terms of viscosity,thermo-oxidation stability and pour point,as well as friction-reducing and anti-wear performance,showing great potential for producing naphthenic base synthetic oils from coal-based chemicals.
基金supported by the National Key Research and Development Program(2021YFC2104400)the Tianjin Science and Technology Plan Project(21JCQNJC00340)the Haihe Laboratory of Sustainable Chemical Transformations。
文摘Synthesizing high-density fuel from lignocellulose can not only achieve green and low-carbon development,but also expand the feedstock source of hydrocarbon fuel.Here,we reported a route of producing high-density fuel from lignin oil and hemicellulose derivative cyclopentanol through alkylation and hydrodeoxygenation,HY with SiO_(2)/Al_(2)O_(3) molar ratio of 5.3 was screened as the alkylation catalyst in the reaction of model phenolic compounds and mixtures,and the reaction conditions were optimized to achieve conversion of phenolic compounds higher than 87%and selectivity of bicyclic and tricyclic products higher than 99%.Then two phenolic pools simulating the composition of two typic lignin oils were studied to validate the alkylation and analyze the competition mechanism of phenolic compounds in mixture system.Finally,real lignin oil from depolymerized of beech powder was tested,and notably80%of phenolic monomers in the oil were converted into fuel precursor.After hydrodeoxygenation,the alkylated product was converted to fuel blend with a density of 0.91 g/mL at 20℃and a freezing point lower than-60℃,very promising as high density fuel.This work provides a facile and energyefficient way of synthesizing high-performance jet fuel directly from lignocellulosic derivatives,which decreases processing energy consumption and improve the utilization rate of feedstock.
