The valorization of biomass to produce biofuels has become a heavily investigated field due to the depletion of fossil fuels and environmental concerns.Among them,the research on deoxygenation of fatty acids or esters...The valorization of biomass to produce biofuels has become a heavily investigated field due to the depletion of fossil fuels and environmental concerns.Among them,the research on deoxygenation of fatty acids or esters derived from biomass as well as municipal sludge organics to produce diesel-like hydrocarbons has become a hot topic.Fatty acid is a key intermediate derived from ester hydrolysis,therefore has attracted more attention as a model compound.In this review,we first introduce and compare the three reaction pathways of hydrodeoxygenation,decarboxylation and decarbonylation,for the deoxygenation of fatty acids and esters.The preference of reaction pathway is closely related to the type of raw materials and catalysts as well as reaction conditions.The special purpose of this review is to summarize the dilemma and possible strategies for deoxygenation of fatty acids,which is expected to provide guidance for future exploration and concentrates.The atom utilization along with stability during reaction in a long time is the most important index for commercial economy.Herein,we propose that the rational design and delicate synthesis of stable single-atom non-noble catalysts may be the best solution.The ultimately goal is aiming to develop sustainable production of green diesel hydrocarbons.展开更多
The direct deoxygenative homo-coupling of benzyl alcohols holds great promise to build up bibenzyl motifs in organic synthesis,yet it remains a grand challenge in selectivity and activity control.Herein,we first disco...The direct deoxygenative homo-coupling of benzyl alcohols holds great promise to build up bibenzyl motifs in organic synthesis,yet it remains a grand challenge in selectivity and activity control.Herein,we first discovered that iron carbide catalysts displayed high efficiency and selectivity in the catalytic deoxygenative homo-coupling of benzyl alcohols into bibenzyls using H_(2)as the reductant.Ir-promoted Fe0@Fe_(5)C_(2)gave the best performance among the investigated catalysts,and a broad scope of substrates with diverse functional groups could be smoothly converted into bibenzyls,with the yield up to 85%.In addition,in the presence of alkenes,three-component coupling reactions between alcohols and alkenes were also for the first time achieved to construct more complex multi-ring molecules.The radical-trapping experiment and FTIR measurements revealed the radical nature of the reaction and the significantly promoted C–O bond activation after carbonization,respectively.This work will provide guidelines for the rational design of efficient and selective catalysts for the alcohol-involved carbon-carbon coupling reactions.展开更多
Geminal diboronates and diarylmethyl boronates are versatile building blocks in synthetic chemistry.We here reported a highly efficient approach for the synthesis of gem-bisborylalkanes and diarylmethyl boronates via ...Geminal diboronates and diarylmethyl boronates are versatile building blocks in synthetic chemistry.We here reported a highly efficient approach for the synthesis of gem-bisborylalkanes and diarylmethyl boronates via cobalt-catalyzed deoxygenative borylation of diaryl ketones.This borylation protocol is compatible with a broad range of functionalized aryl groups,providing access to a wide array of boronic esters.The resulting boronic esters can be further transformed to various cross-coupling products and TPEs that represent important structural motifs in organic chemistry and materials science.展开更多
To produce paraffin from hydrogenation/deoxygenation of palmitic acid,model compound of bio-oil obtained by hydrothermal liquefaction(HTL)of microalgae has been an attractive focus in recent years.In order to avoid en...To produce paraffin from hydrogenation/deoxygenation of palmitic acid,model compound of bio-oil obtained by hydrothermal liquefaction(HTL)of microalgae has been an attractive focus in recent years.In order to avoid energy-intensive separation process of water and bio-oil,it is of importance that deoxygenation upgrading of fatty acids under hydrothermal conditions similar to HTL process.Herein,it is the first time to explore the application of activated carbon(AC)-supported non-noble-metal catalysts,such as Ni,Co,and Mo,and so on,in the hydrothermal hydrogenation/deoxygenation of long-chain fatty acids,and the obtained Ni/AC-H(the Ni/AC was further H_(2)pre-reduced)is one of the best catalysts.In addition,it is found that the catalytic activity can be further improved by H_(2)pre-reduction of catalyst.Characterization results that are more low valences of nickel and oxygen vacancy can be obtained after H_(2)pre-reduction,thus significant promoting the deoxygenation especially the decarbonylation pathway of fatty acids.The total alkanes yield can reaches 95.9%at optimal conditions(280℃,360 min).This work confirmed that the low-priced AC-supported non-noble-metal catalysts have great potential compared with the noble-metal catalyst,in hydrothermal upgrading of bio-oil.展开更多
Mo/o-quinone complexes have shown great capability in promoting deoxygenation of carbonyl groups in the presence of appropriate reducing agents,which yields key Mo-carbene complexes and subsequently undergoes further ...Mo/o-quinone complexes have shown great capability in promoting deoxygenation of carbonyl groups in the presence of appropriate reducing agents,which yields key Mo-carbene complexes and subsequently undergoes further transformations.However,the detailed mechanistic pathways for the deoxygenation of carbonyl groups with the assistance of additive remain unclear.Herein,a comprehensive density functional theory(DFT)study was performed to gain mechanistic insights into the Mo-catalyzed deoxygenative coupling of aromatic aldehydes to produce diaryl alkenes with the assistance of triphenylphosphine(PPh_(3))as a reductant.Computational results suggest that the Mo(IV)complex(with two o-quinone ligands)is more efficient than the commonly proposed Mo(Ⅱ)complex(with one o-quinone ligand)in mediating the deoxygenation of aromatic aldehyde to yield a critical Mo-carbene intermediate.An outer-sphere stepwise mechanistic pathway is suggested for the PPh3 assisted deoxygenation of aromatic aldehyde,which proceeds through the generation of an adduct with aldehyde via P—O bond formation followed by the breaking of C—O bond of aldehyde to give the key Mo(IV)-carbene intermediate.The commonly proposed oxidative addition of carbonyl group onto Mo(Ⅱ)to form an oxo-Mo-carbene intermediate might not be feasible.After the formation of the Schrock-type Mo(IV)carbene intermediate,a metathesis mechanistic pathway via a[2+2]cycloaddition adduct is reasonable to afford the final product.The factors accounting for the formation of Mo(IV)carbene and the stereo-selectivity of the product are discussed.展开更多
The chemical transformation of natural oils provides alternatives to limited fossil fuels and produces compounds with added value for the chemical industries.The selective deoxygenation of natural oils to diesel-range...The chemical transformation of natural oils provides alternatives to limited fossil fuels and produces compounds with added value for the chemical industries.The selective deoxygenation of natural oils to diesel-ranged hydrocarbons,bio-jet fuels,or fatty alcohols with controllable selectivity is especially attractive in natural oil feedstock biorefineries.This review presents recent progress in catalytic deoxygenation of natural oils or related model compounds(e.g.,fatty acids)to renewable liquid fuels(green diesel and bio-jet fuels)and valuable fatty alcohols(unsaturated and saturated fatty alcohols).Besides,it discusses and compares the existing and potential strategies to control the product selectivity over heterogeneous catalysts.Most research conducted and reviewed has only addressed the production of one category;therefore,a new integrative vision exploring how to direct the process toward fuel and/or chemicals is urgently needed.Thus,work conducted to date addressing the development of new catalysts and studying the influence of the reaction parameters(e.g.,temperature,time and hydrogen pressure)is summarized and critically discussed from a green and sustainable perspective using efficiency indicators(e.g.,yields,selectivity,turnover frequencies and catalysts lifetime).Special attention has been given to the chemical transformations occurring to identify key descriptors to tune the selectivity toward target products by manipulating the reaction conditions and the structures of the catalysts.Finally,the challenges and future research goals to develop novel and holistic natural oil biorefineries are proposed.As a result,this critical review provides the readership with appropriate information to selectively control the transformation of natural oils into either biofuels and/or value-added chemicals.This new flexible vision can help pave the wave to suit the present and future market needs.展开更多
An efficient and practical radical chain deoxygenation method by phosphorus centered radicals generated from hypophosphorous acid was developed in the synthesis of analogues of paclitaxel.
The low-temperature coal tar contains a considerable number of oxygen-containing compounds,which results in poor quality.The catalytic hydrodeoxygenation of oxygen-containing compound to an added-value chemical compou...The low-temperature coal tar contains a considerable number of oxygen-containing compounds,which results in poor quality.The catalytic hydrodeoxygenation of oxygen-containing compound to an added-value chemical compound is one of the most efficient methods to upgrade coal tar.In this study,density functional theory calculations are employed to assess and analyze in detail the hydrodeoxygenation of dibenzofuran,as a model compound of coal tar,on the Ni(111)surface.The obtained results indicate that dibenzofuran can be firstly hydrogenated to tetra hy d rod i be nzofura n and hexahydfodibenzofufan.The five-membered-ring opening reaction of tetrahydrodibenzofuran is more straightforward than that of hexahydrodibenzofuran(Ea=0.71 eV vs.1.66 eV).Then,both pathways generate an intermediate 2-cyclohexylphenoxy compound.One part of 2-cyclohexylphenoxy is hydrogenated to 2-cyclohexylphenol and consecutively hydrogenated to cyclohexylcyclohexanol,and another part is directly hydrogenated to cyclohexylcyclohexanone.The hydrogenated intermediates of2-cyclohexylphenol have higher deoxygenation barriers than 2-cyclohexylphenol and cyclohexylcy clohexanol.During the hydrogenation process of cyclohexylcyclohexanone to cyclohexylcyclohexanol,the intermediate 26,formed by adding H to O atom of cyclohexylcyclohexanone,exhibits the lowest deoxygenation barrier of 1.08 eV.High hydrogen coverage may promote the hydrogenation of tetrahydrodibenzofuran,hexahydrodibenzofuran,and intermediate 26 to generate dodecahydrodibenzofuran and cyclohexylcyclohexanol.This dibenzofuran hydrodeoxygenation reaction mechanism corroborates well with previous experimental results and provides a theoretical basis for further optimization of the design of nickel-based catalysts.展开更多
The reductive deoxygenation of aldehydes and ketones into the corresponding alkanes is accomplished by LiAlH4, in the presence of Lewis acid InBr3. It provides a convenient method to complete the transformation from c...The reductive deoxygenation of aldehydes and ketones into the corresponding alkanes is accomplished by LiAlH4, in the presence of Lewis acid InBr3. It provides a convenient method to complete the transformation from carbonyl compounds to alkanes.展开更多
Herein,we report a borane-promoted reductive deoxygenation coupling reaction to synthesize sulfides.This reaction features excellent functional group compatibility,high efficiency,broad substrate scope,and application...Herein,we report a borane-promoted reductive deoxygenation coupling reaction to synthesize sulfides.This reaction features excellent functional group compatibility,high efficiency,broad substrate scope,and application in late-stage functionalization of biomolecules.Preliminary mechanistic studies suggest diaryl sulfides are the intermediates of this reaction.Moreover,the real active aryl sulfide anions may be generated in situ with the aid of B2pin2 and react with alkyl tosylates through a concerted SN2 pathway.展开更多
The reactions of halocarbenes with pre-aromatic ketones 1, 2 resulted in cyclopropanation and deoxygenation products. The varying product ratio could be accounted for by a mechanism involving the carbonyl ylide interm...The reactions of halocarbenes with pre-aromatic ketones 1, 2 resulted in cyclopropanation and deoxygenation products. The varying product ratio could be accounted for by a mechanism involving the carbonyl ylide intermediate.展开更多
The deoxygenation reaction of heptanones, cycloheptanone, cycloheptatrienone or substituted cycloheptatrienone with dihalo-carbene results in carbon monoxide and corresponding halides. The yield of CO produced by 2 , ...The deoxygenation reaction of heptanones, cycloheptanone, cycloheptatrienone or substituted cycloheptatrienone with dihalo-carbene results in carbon monoxide and corresponding halides. The yield of CO produced by 2 , 4 , 6-triphenylcycloheptatrienone is 2.6-3.5 times as high as that produced by the saturated heptanones. The structures, energies, charge distributions, bond orders, and other relative parameters of the dihalocarbonyl glides were calculated by using the SCF-MNDO method. The obtained data reveal that the ylides from cycloheptatrienone have aromatic structure and are different from those produced from saturated cycloheptanone. The reactivities of the dihalocarbonyl ylides are discussed. It is proposed that this aromatic structure should be responsible for the high yield of CO from the reaction of cycloheptatrienone with dihalocarbene.展开更多
An incubation experiment was conducted to simulate the effect of flooding onwater deoxygenation in acid sulfate soil floodplain systems. The originally oxygenated 'floodwater'could be deoxygenated immediately ...An incubation experiment was conducted to simulate the effect of flooding onwater deoxygenation in acid sulfate soil floodplain systems. The originally oxygenated 'floodwater'could be deoxygenated immediately following 'flooding' and it is likelythat this was caused mainlyby decomposition of organic debris from the inundated plants. Deoxygenation eventually led to thedepletion of dissolved oxygen (DO) in the 'floodwater' and it is highly possible that this resultedin the transformations of ferric Fe to ferrous Fe, sulfate to hydrogen sulfide. and organic nitrogento ammonia (ammonification). The accumulation of these reduced substances allows the 'floodwater'to develop DO-consuming capacity (DOCC). When the 'floodwater' is mixed with the introducedoxygenated water, apart from the dilution effects, the reduced substances contained in the'floodwater' oxidize to further consume DO carried by the introduced water. However, it appears thatthe DO drop in the mixed water can only last for a few hours if no additional DO-depleted'floodwater' is added. Entry of atmospheric oxygen into the water can raise the DO level of themixed water arid lower water pH through the oxidation of the reduced substances.展开更多
Organoboron compounds are widely used in synthetic chemistry,pharmaceutical chemistry and material chemistry.Among various organoboron compounds,benzylboronic esters are unique and highly reactive,making them suitable...Organoboron compounds are widely used in synthetic chemistry,pharmaceutical chemistry and material chemistry.Among various organoboron compounds,benzylboronic esters are unique and highly reactive,making them suitable benzylation reagents.At present,the synthetic methods for the syntheses of benzylboronic esters are still insufficient to meet their demands.It is necessary to develop novel and practical methods for their preparation.In this work,a novel copper‐catalyzed deoxygenative gem‐hydroborylation of aromatic aldehydes and ketones has been developed.This direct and operationally simple protocol provides an effective approach for the synthesis of a variety of primary and secondary benzylboronates,in which broad functional group tolerance was presented.Widely available B2pin2(pin=pinacol)was used as the boron source and alcoholic proton was applied as the hydride source.展开更多
Catalytic oxidation of CH_(4) has been proved to be an attractive option for landfill gas(LFG) upgrading.However, coking of catalysts in catalytic LFG deoxygen has been clearly observed in industrial applications. In ...Catalytic oxidation of CH_(4) has been proved to be an attractive option for landfill gas(LFG) upgrading.However, coking of catalysts in catalytic LFG deoxygen has been clearly observed in industrial applications. In this regard, it is necessary to investigate whether coke deposition originates from CH_(4) or volatile organic compounds present in LFG, and the influence of coke deposition on catalytic performance. Herein,we evaluate the LFG deoxygen on Pt/γ-Al_(2)O_(3) catalyst in simulated LFG(CH_(4), CO_(2), O_(2), N_(2)) and its co-feed with representative volatile organic compounds, ethylbenzene, toluene, benzene and cyclohexane. The results show that the coking of the catalyst is originated from volatile organic compounds rather than CH_(4). The Pt/γ-Al_(2)O_(3) catalyst does not deactivate during LFG deoxygen process, even significant amount of coke deposited, up to 18.15%(mass). Characterization analyses reveal that although coke deposition overall covers the catalyst surface, resulting in mesopores blockage and a reduced number of accessible Pt sites, however, the coke formed, H-rich carbonaceous components, behaves as counterpart for O_(2) elimination. Besides, the coke deposited is mainly filamentous. Thus, coke formation has little negative effect on the overall catalytic performance of Pt/γ-Al_(2)O_(3) catalyst ultimately. The results obtained in this work are helpful for the rational design of robust Pt based catalysts for LFG deoxygen without undue attention to their coking properties, and also favor the innovation of more attractive purification scheme configurations.展开更多
The traditional deoxygenation techniques for cyclodextrin induced room temperature phosphorescence (CD-RTP) include N-2(g)purging([1]) and Na2SO3 chemical deoxygenation. In this paper, with 1-bromocyclohexane (1-BrCH)...The traditional deoxygenation techniques for cyclodextrin induced room temperature phosphorescence (CD-RTP) include N-2(g)purging([1]) and Na2SO3 chemical deoxygenation. In this paper, with 1-bromocyclohexane (1-BrCH) as an external heavy atom perturber, 7,8-benzoquinoline (7,8-BQ) was used as a model compound, hydrogen and carbon dioxide are used for deoxygenation in CD-RTP and compared with two traditional deoxygenation techniques. The results show that the new deoxygenation techniques have obvious advantages such as simpler facilities, faster speed of deoxygenation and wider acidity range etc.展开更多
Fatty acids with different chain length were deoxygenated in the absence of hydrogen (caprylic acid (CA), lauric acid (LA) and stearic acid (SA)). The catalytic tests were carried over Pd-containing catalysts out in a...Fatty acids with different chain length were deoxygenated in the absence of hydrogen (caprylic acid (CA), lauric acid (LA) and stearic acid (SA)). The catalytic tests were carried over Pd-containing catalysts out in a batch reactor under inert gas for 6 h at 250°C to 350°C and pressures from 18 to 75 bar in the absence of additionally fed hydrogen. Pd-containing catalysts were tested;the best performing catalyst was 10% Pd/C with 63% undecane yield at 327°C. These catalysts were used for a comparative decarboxylation of CA, LA and SA. At equal reaction conditions (300°C, 6 h), the chain length of the fatty acid had a strong impact on the conversion, which was steadily increasing, whereas the alkane selectivity ran through a maximum. This work demonstrated the usability of Pd-containing catalysts for the decarboxylation of various fatty acids in the absence of additionally fed hydrogen with respect to the manufacture of hydrocarbons that can be used as blending components for fuels.展开更多
The deoxygenative radical reaction of alcohols is a critical topic for alcohol functionalization.This reaction involves cleavage of the C-O bond in alcohols,generating diverse alkyl carbon(sp^(3))radical intermediates...The deoxygenative radical reaction of alcohols is a critical topic for alcohol functionalization.This reaction involves cleavage of the C-O bond in alcohols,generating diverse alkyl carbon(sp^(3))radical intermediates.However,the high bond dissociation energy of the C-O bond(about 95 kcal/mol)makes deoxygenative transformation under mild conditions particularly challenging in organic synthesis.In recent years,researchers have successfully accomplished functionalization by selectively cleaving the C-O bonds and developing various strategies for constructing C(sp^(3))-C and C(sp^(3))-X bonds,thereby providing crucial pathways for synthesizing target molecules containing alkyl carbon moieties.Consequently,selective deoxygenative transformations of alcohols hold significant potential for advancing synthetic chemistry.This article comprehensively reviews strategies addressing alcohol deoxygenation over the past decade.The most representative strategies for deoxygenation primarily rely on metal-reducing agents,pre-activated generation of active derivatives,or the utilization of activating reagents to accomplish alcohol deoxygenation reactions.展开更多
As the prominence of green chemistry continues to grow,there is an increasing need to explore and develop alternative energy and fuel sources.Renewable biomass is expected to play a pivotal role in this transition,wit...As the prominence of green chemistry continues to grow,there is an increasing need to explore and develop alternative energy and fuel sources.Renewable biomass is expected to play a pivotal role in this transition,with lactic acid being particularly noteworthy due to its abundance and affordability.Given its prevalence,lactic acid offers a notable opportunity for transformation into high-value-added products.Here,we describe a method for the enantioconvergent substitution of the hydroxy group at theα-position in lactic acid derivatives by a carbon group,thereby streamlining the synthesis of various bioactive compounds.This reaction achieves both C-O bond cleavage and stereochemical C-C bond formation in a one-pot process.Our approach involves a catalyst system based on nickel and relies on two distinct ligands—a chiral bis(imidazoline)and a phthalimide.Investigations into the underlying mechanisms have provided valuable insights into the role of phthalimide in this process.展开更多
Comprehensive Summary:The divergent synthesis of 2-quinolinones and indolin-3-ones through unprecedented Mo-catalyzed controllable carbonyl deoxygenative coupling and formal deoxygenative N-H insertion reactions was r...Comprehensive Summary:The divergent synthesis of 2-quinolinones and indolin-3-ones through unprecedented Mo-catalyzed controllable carbonyl deoxygenative coupling and formal deoxygenative N-H insertion reactions was reported.By simply changing the molybdenum catalytic conditions,both product categories were produced in generally good yields and with high chemoselectivities from the same starting materials.This strategy was robust,convenient and ready for the rapid construction of diverse product libraries.展开更多
基金supported by the National Key R&D Program of China (No. 2021YFE0104900)Guangdong Basic and Applied Basic Research Foundation (No. 2023A1515030018)
文摘The valorization of biomass to produce biofuels has become a heavily investigated field due to the depletion of fossil fuels and environmental concerns.Among them,the research on deoxygenation of fatty acids or esters derived from biomass as well as municipal sludge organics to produce diesel-like hydrocarbons has become a hot topic.Fatty acid is a key intermediate derived from ester hydrolysis,therefore has attracted more attention as a model compound.In this review,we first introduce and compare the three reaction pathways of hydrodeoxygenation,decarboxylation and decarbonylation,for the deoxygenation of fatty acids and esters.The preference of reaction pathway is closely related to the type of raw materials and catalysts as well as reaction conditions.The special purpose of this review is to summarize the dilemma and possible strategies for deoxygenation of fatty acids,which is expected to provide guidance for future exploration and concentrates.The atom utilization along with stability during reaction in a long time is the most important index for commercial economy.Herein,we propose that the rational design and delicate synthesis of stable single-atom non-noble catalysts may be the best solution.The ultimately goal is aiming to develop sustainable production of green diesel hydrocarbons.
文摘The direct deoxygenative homo-coupling of benzyl alcohols holds great promise to build up bibenzyl motifs in organic synthesis,yet it remains a grand challenge in selectivity and activity control.Herein,we first discovered that iron carbide catalysts displayed high efficiency and selectivity in the catalytic deoxygenative homo-coupling of benzyl alcohols into bibenzyls using H_(2)as the reductant.Ir-promoted Fe0@Fe_(5)C_(2)gave the best performance among the investigated catalysts,and a broad scope of substrates with diverse functional groups could be smoothly converted into bibenzyls,with the yield up to 85%.In addition,in the presence of alkenes,three-component coupling reactions between alcohols and alkenes were also for the first time achieved to construct more complex multi-ring molecules.The radical-trapping experiment and FTIR measurements revealed the radical nature of the reaction and the significantly promoted C–O bond activation after carbonization,respectively.This work will provide guidelines for the rational design of efficient and selective catalysts for the alcohol-involved carbon-carbon coupling reactions.
基金financial support from the National Natural Science Foundation of China(Nos.22271086 and 21971059)the National Program for Thousand Young Talents of Chinathe Fundamental Research Funds for the Central Universities。
文摘Geminal diboronates and diarylmethyl boronates are versatile building blocks in synthetic chemistry.We here reported a highly efficient approach for the synthesis of gem-bisborylalkanes and diarylmethyl boronates via cobalt-catalyzed deoxygenative borylation of diaryl ketones.This borylation protocol is compatible with a broad range of functionalized aryl groups,providing access to a wide array of boronic esters.The resulting boronic esters can be further transformed to various cross-coupling products and TPEs that represent important structural motifs in organic chemistry and materials science.
基金the financial support from National Natural Science Foundation of China(21838006,21776159)National Key Research and Development Program of China(2018YFC1902101)。
文摘To produce paraffin from hydrogenation/deoxygenation of palmitic acid,model compound of bio-oil obtained by hydrothermal liquefaction(HTL)of microalgae has been an attractive focus in recent years.In order to avoid energy-intensive separation process of water and bio-oil,it is of importance that deoxygenation upgrading of fatty acids under hydrothermal conditions similar to HTL process.Herein,it is the first time to explore the application of activated carbon(AC)-supported non-noble-metal catalysts,such as Ni,Co,and Mo,and so on,in the hydrothermal hydrogenation/deoxygenation of long-chain fatty acids,and the obtained Ni/AC-H(the Ni/AC was further H_(2)pre-reduced)is one of the best catalysts.In addition,it is found that the catalytic activity can be further improved by H_(2)pre-reduction of catalyst.Characterization results that are more low valences of nickel and oxygen vacancy can be obtained after H_(2)pre-reduction,thus significant promoting the deoxygenation especially the decarbonylation pathway of fatty acids.The total alkanes yield can reaches 95.9%at optimal conditions(280℃,360 min).This work confirmed that the low-priced AC-supported non-noble-metal catalysts have great potential compared with the noble-metal catalyst,in hydrothermal upgrading of bio-oil.
文摘Mo/o-quinone complexes have shown great capability in promoting deoxygenation of carbonyl groups in the presence of appropriate reducing agents,which yields key Mo-carbene complexes and subsequently undergoes further transformations.However,the detailed mechanistic pathways for the deoxygenation of carbonyl groups with the assistance of additive remain unclear.Herein,a comprehensive density functional theory(DFT)study was performed to gain mechanistic insights into the Mo-catalyzed deoxygenative coupling of aromatic aldehydes to produce diaryl alkenes with the assistance of triphenylphosphine(PPh_(3))as a reductant.Computational results suggest that the Mo(IV)complex(with two o-quinone ligands)is more efficient than the commonly proposed Mo(Ⅱ)complex(with one o-quinone ligand)in mediating the deoxygenation of aromatic aldehyde to yield a critical Mo-carbene intermediate.An outer-sphere stepwise mechanistic pathway is suggested for the PPh3 assisted deoxygenation of aromatic aldehyde,which proceeds through the generation of an adduct with aldehyde via P—O bond formation followed by the breaking of C—O bond of aldehyde to give the key Mo(IV)-carbene intermediate.The commonly proposed oxidative addition of carbonyl group onto Mo(Ⅱ)to form an oxo-Mo-carbene intermediate might not be feasible.After the formation of the Schrock-type Mo(IV)carbene intermediate,a metathesis mechanistic pathway via a[2+2]cycloaddition adduct is reasonable to afford the final product.The factors accounting for the formation of Mo(IV)carbene and the stereo-selectivity of the product are discussed.
基金financially supported by the National Natural Science Foundation of China (No.21536007)the 111 Project (B17030)+1 种基金support from China Scholarship Council (CSC No.202006240156)the Spanish Ministry of Science,Innovation and Universities for the Juan de la Cierva (JdC)fellowships (Grant Numbers FJCI-2016-30847 and IJC2018-037110-I)awarded.
文摘The chemical transformation of natural oils provides alternatives to limited fossil fuels and produces compounds with added value for the chemical industries.The selective deoxygenation of natural oils to diesel-ranged hydrocarbons,bio-jet fuels,or fatty alcohols with controllable selectivity is especially attractive in natural oil feedstock biorefineries.This review presents recent progress in catalytic deoxygenation of natural oils or related model compounds(e.g.,fatty acids)to renewable liquid fuels(green diesel and bio-jet fuels)and valuable fatty alcohols(unsaturated and saturated fatty alcohols).Besides,it discusses and compares the existing and potential strategies to control the product selectivity over heterogeneous catalysts.Most research conducted and reviewed has only addressed the production of one category;therefore,a new integrative vision exploring how to direct the process toward fuel and/or chemicals is urgently needed.Thus,work conducted to date addressing the development of new catalysts and studying the influence of the reaction parameters(e.g.,temperature,time and hydrogen pressure)is summarized and critically discussed from a green and sustainable perspective using efficiency indicators(e.g.,yields,selectivity,turnover frequencies and catalysts lifetime).Special attention has been given to the chemical transformations occurring to identify key descriptors to tune the selectivity toward target products by manipulating the reaction conditions and the structures of the catalysts.Finally,the challenges and future research goals to develop novel and holistic natural oil biorefineries are proposed.As a result,this critical review provides the readership with appropriate information to selectively control the transformation of natural oils into either biofuels and/or value-added chemicals.This new flexible vision can help pave the wave to suit the present and future market needs.
文摘An efficient and practical radical chain deoxygenation method by phosphorus centered radicals generated from hypophosphorous acid was developed in the synthesis of analogues of paclitaxel.
基金financial support from the National Key Research and Development Program of China(2016YFB0600305)National Natural Science Foundation of China(21808153,22078220)。
文摘The low-temperature coal tar contains a considerable number of oxygen-containing compounds,which results in poor quality.The catalytic hydrodeoxygenation of oxygen-containing compound to an added-value chemical compound is one of the most efficient methods to upgrade coal tar.In this study,density functional theory calculations are employed to assess and analyze in detail the hydrodeoxygenation of dibenzofuran,as a model compound of coal tar,on the Ni(111)surface.The obtained results indicate that dibenzofuran can be firstly hydrogenated to tetra hy d rod i be nzofura n and hexahydfodibenzofufan.The five-membered-ring opening reaction of tetrahydrodibenzofuran is more straightforward than that of hexahydrodibenzofuran(Ea=0.71 eV vs.1.66 eV).Then,both pathways generate an intermediate 2-cyclohexylphenoxy compound.One part of 2-cyclohexylphenoxy is hydrogenated to 2-cyclohexylphenol and consecutively hydrogenated to cyclohexylcyclohexanol,and another part is directly hydrogenated to cyclohexylcyclohexanone.The hydrogenated intermediates of2-cyclohexylphenol have higher deoxygenation barriers than 2-cyclohexylphenol and cyclohexylcy clohexanol.During the hydrogenation process of cyclohexylcyclohexanone to cyclohexylcyclohexanol,the intermediate 26,formed by adding H to O atom of cyclohexylcyclohexanone,exhibits the lowest deoxygenation barrier of 1.08 eV.High hydrogen coverage may promote the hydrogenation of tetrahydrodibenzofuran,hexahydrodibenzofuran,and intermediate 26 to generate dodecahydrodibenzofuran and cyclohexylcyclohexanol.This dibenzofuran hydrodeoxygenation reaction mechanism corroborates well with previous experimental results and provides a theoretical basis for further optimization of the design of nickel-based catalysts.
基金the National Natural Science Foundation of China(29872018&29972026)the Key Laboratory of Elemento-oiganic Cheraistiy,Nankai University and RFDP,China's Ministry of Higher Education(1999005520)for their financial support
文摘The reductive deoxygenation of aldehydes and ketones into the corresponding alkanes is accomplished by LiAlH4, in the presence of Lewis acid InBr3. It provides a convenient method to complete the transformation from carbonyl compounds to alkanes.
基金support from Natural Science Foundation of Sichuan(No.2021YJ0413)Sichuan Key Laboratory of Medical Imaging(North Sichuan Medical College,No.SKLMI201901)+2 种基金Strategic Cooperation of Science and Technology between Nanchong City and North Sichuan Medical College(Nos.19SXHZ0441,19SXHZ0227)Chongqing Postdoctoral Science Foundation(No.cstc2020jcyj-bshX0052)China Postdoctoral Science Foundation(No.2020M673121).
文摘Herein,we report a borane-promoted reductive deoxygenation coupling reaction to synthesize sulfides.This reaction features excellent functional group compatibility,high efficiency,broad substrate scope,and application in late-stage functionalization of biomolecules.Preliminary mechanistic studies suggest diaryl sulfides are the intermediates of this reaction.Moreover,the real active aryl sulfide anions may be generated in situ with the aid of B2pin2 and react with alkyl tosylates through a concerted SN2 pathway.
文摘The reactions of halocarbenes with pre-aromatic ketones 1, 2 resulted in cyclopropanation and deoxygenation products. The varying product ratio could be accounted for by a mechanism involving the carbonyl ylide intermediate.
文摘The deoxygenation reaction of heptanones, cycloheptanone, cycloheptatrienone or substituted cycloheptatrienone with dihalo-carbene results in carbon monoxide and corresponding halides. The yield of CO produced by 2 , 4 , 6-triphenylcycloheptatrienone is 2.6-3.5 times as high as that produced by the saturated heptanones. The structures, energies, charge distributions, bond orders, and other relative parameters of the dihalocarbonyl glides were calculated by using the SCF-MNDO method. The obtained data reveal that the ylides from cycloheptatrienone have aromatic structure and are different from those produced from saturated cycloheptanone. The reactivities of the dihalocarbonyl ylides are discussed. It is proposed that this aromatic structure should be responsible for the high yield of CO from the reaction of cycloheptatrienone with dihalocarbene.
基金Project partly supported by Australian Research Council and NSW Agriculture.
文摘An incubation experiment was conducted to simulate the effect of flooding onwater deoxygenation in acid sulfate soil floodplain systems. The originally oxygenated 'floodwater'could be deoxygenated immediately following 'flooding' and it is likelythat this was caused mainlyby decomposition of organic debris from the inundated plants. Deoxygenation eventually led to thedepletion of dissolved oxygen (DO) in the 'floodwater' and it is highly possible that this resultedin the transformations of ferric Fe to ferrous Fe, sulfate to hydrogen sulfide. and organic nitrogento ammonia (ammonification). The accumulation of these reduced substances allows the 'floodwater'to develop DO-consuming capacity (DOCC). When the 'floodwater' is mixed with the introducedoxygenated water, apart from the dilution effects, the reduced substances contained in the'floodwater' oxidize to further consume DO carried by the introduced water. However, it appears thatthe DO drop in the mixed water can only last for a few hours if no additional DO-depleted'floodwater' is added. Entry of atmospheric oxygen into the water can raise the DO level of themixed water arid lower water pH through the oxidation of the reduced substances.
文摘Organoboron compounds are widely used in synthetic chemistry,pharmaceutical chemistry and material chemistry.Among various organoboron compounds,benzylboronic esters are unique and highly reactive,making them suitable benzylation reagents.At present,the synthetic methods for the syntheses of benzylboronic esters are still insufficient to meet their demands.It is necessary to develop novel and practical methods for their preparation.In this work,a novel copper‐catalyzed deoxygenative gem‐hydroborylation of aromatic aldehydes and ketones has been developed.This direct and operationally simple protocol provides an effective approach for the synthesis of a variety of primary and secondary benzylboronates,in which broad functional group tolerance was presented.Widely available B2pin2(pin=pinacol)was used as the boron source and alcoholic proton was applied as the hydride source.
基金the financial supports from the National Natural Science Foundation of China (22076077, 21577060)Jiangsu Science and Technology Department (BK20191256)Analysis & Test Fund of Nanjing University。
文摘Catalytic oxidation of CH_(4) has been proved to be an attractive option for landfill gas(LFG) upgrading.However, coking of catalysts in catalytic LFG deoxygen has been clearly observed in industrial applications. In this regard, it is necessary to investigate whether coke deposition originates from CH_(4) or volatile organic compounds present in LFG, and the influence of coke deposition on catalytic performance. Herein,we evaluate the LFG deoxygen on Pt/γ-Al_(2)O_(3) catalyst in simulated LFG(CH_(4), CO_(2), O_(2), N_(2)) and its co-feed with representative volatile organic compounds, ethylbenzene, toluene, benzene and cyclohexane. The results show that the coking of the catalyst is originated from volatile organic compounds rather than CH_(4). The Pt/γ-Al_(2)O_(3) catalyst does not deactivate during LFG deoxygen process, even significant amount of coke deposited, up to 18.15%(mass). Characterization analyses reveal that although coke deposition overall covers the catalyst surface, resulting in mesopores blockage and a reduced number of accessible Pt sites, however, the coke formed, H-rich carbonaceous components, behaves as counterpart for O_(2) elimination. Besides, the coke deposited is mainly filamentous. Thus, coke formation has little negative effect on the overall catalytic performance of Pt/γ-Al_(2)O_(3) catalyst ultimately. The results obtained in this work are helpful for the rational design of robust Pt based catalysts for LFG deoxygen without undue attention to their coking properties, and also favor the innovation of more attractive purification scheme configurations.
文摘The traditional deoxygenation techniques for cyclodextrin induced room temperature phosphorescence (CD-RTP) include N-2(g)purging([1]) and Na2SO3 chemical deoxygenation. In this paper, with 1-bromocyclohexane (1-BrCH) as an external heavy atom perturber, 7,8-benzoquinoline (7,8-BQ) was used as a model compound, hydrogen and carbon dioxide are used for deoxygenation in CD-RTP and compared with two traditional deoxygenation techniques. The results show that the new deoxygenation techniques have obvious advantages such as simpler facilities, faster speed of deoxygenation and wider acidity range etc.
文摘Fatty acids with different chain length were deoxygenated in the absence of hydrogen (caprylic acid (CA), lauric acid (LA) and stearic acid (SA)). The catalytic tests were carried over Pd-containing catalysts out in a batch reactor under inert gas for 6 h at 250°C to 350°C and pressures from 18 to 75 bar in the absence of additionally fed hydrogen. Pd-containing catalysts were tested;the best performing catalyst was 10% Pd/C with 63% undecane yield at 327°C. These catalysts were used for a comparative decarboxylation of CA, LA and SA. At equal reaction conditions (300°C, 6 h), the chain length of the fatty acid had a strong impact on the conversion, which was steadily increasing, whereas the alkane selectivity ran through a maximum. This work demonstrated the usability of Pd-containing catalysts for the decarboxylation of various fatty acids in the absence of additionally fed hydrogen with respect to the manufacture of hydrocarbons that can be used as blending components for fuels.
基金supported by the National Natural Science Foundation of China(22401223)the Natural Science Foundation of Hubei Province(2024AFB315)+6 种基金the Science and Technology Research Project of Hubei Provincial Department of Education(Q20231501)the Open and Innovation Fund of Hubei Three Gorges Laboratory(SC240004)the Innovation Project of Engineering Research Center of Phosphorus Resources Development and Utilization of Ministry of Education(LCX202403)the Open Research Fund of School of Chemistry and Chemical Engineering,the Henan Normal University(2020ZD02)the Chemical Synthesis and Pollution Control Key Laboratory of Sichuan Province(CSPC202306)the Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology(BM2012110)the Knowledge Innovation Program of Wuhan-Basic Research(2023020201010142)。
文摘The deoxygenative radical reaction of alcohols is a critical topic for alcohol functionalization.This reaction involves cleavage of the C-O bond in alcohols,generating diverse alkyl carbon(sp^(3))radical intermediates.However,the high bond dissociation energy of the C-O bond(about 95 kcal/mol)makes deoxygenative transformation under mild conditions particularly challenging in organic synthesis.In recent years,researchers have successfully accomplished functionalization by selectively cleaving the C-O bonds and developing various strategies for constructing C(sp^(3))-C and C(sp^(3))-X bonds,thereby providing crucial pathways for synthesizing target molecules containing alkyl carbon moieties.Consequently,selective deoxygenative transformations of alcohols hold significant potential for advancing synthetic chemistry.This article comprehensively reviews strategies addressing alcohol deoxygenation over the past decade.The most representative strategies for deoxygenation primarily rely on metal-reducing agents,pre-activated generation of active derivatives,or the utilization of activating reagents to accomplish alcohol deoxygenation reactions.
基金supported by the National Natural Science Foundation of China(22201216 to Ze-Peng Yang)the National Key Research&Development Program of China(2023YFA1508600 to Ze-Peng Yang)the Fundamental Research Funds for the Central Universities(22120240079 to Ze-Peng Yang,and 22120230504 to Kaining Duanmu)。
文摘As the prominence of green chemistry continues to grow,there is an increasing need to explore and develop alternative energy and fuel sources.Renewable biomass is expected to play a pivotal role in this transition,with lactic acid being particularly noteworthy due to its abundance and affordability.Given its prevalence,lactic acid offers a notable opportunity for transformation into high-value-added products.Here,we describe a method for the enantioconvergent substitution of the hydroxy group at theα-position in lactic acid derivatives by a carbon group,thereby streamlining the synthesis of various bioactive compounds.This reaction achieves both C-O bond cleavage and stereochemical C-C bond formation in a one-pot process.Our approach involves a catalyst system based on nickel and relies on two distinct ligands—a chiral bis(imidazoline)and a phthalimide.Investigations into the underlying mechanisms have provided valuable insights into the role of phthalimide in this process.
基金financial support from the National Key R&D Program of China(2021YFA1502500)the National Natural Science Foundation of china(22171236 and 22371238).
文摘Comprehensive Summary:The divergent synthesis of 2-quinolinones and indolin-3-ones through unprecedented Mo-catalyzed controllable carbonyl deoxygenative coupling and formal deoxygenative N-H insertion reactions was reported.By simply changing the molybdenum catalytic conditions,both product categories were produced in generally good yields and with high chemoselectivities from the same starting materials.This strategy was robust,convenient and ready for the rapid construction of diverse product libraries.
