Showing papers on "Halide published in 2009"
TL;DR: In this paper, the methods of forming nanoprisms or nanorods from gold seed particles by adding controlled amounts of iodide ion to the growth solution are disclosed, and the results show that the resulting nanorod can be formed from gold seeds.
Abstract: Methods of forming nanoprisms or nanorods from gold seed particles by adding controlled amounts of iodide ion to the growth solution are disclosed.
339 citations
TL;DR: A novel protocol for the direct carbon dioxide insertion into aryl halides in a catalytic manner is presented, distinguished by its mild conditions, allowing the tolerance of a wide range of functional groups and substitution patterns.
Abstract: A novel protocol for the direct carbon dioxide insertion (CO2) into aryl halides in a catalytic manner is presented herein. Unlike other carboxylation methods using CO2, there is no need for the synthesis of the corresponding organometallic intermediates. Additionally, and in contrast to the well-established carbonylation processes, our protocol does not use highly toxic CO for the preparation of benzoic acids. Furthermore, this method is distinguished by its mild conditions, allowing the tolerance of a wide range of functional groups and substitution patterns. The crucial step of the process involves a challenging catalytic CO2 insertion into Pd−C bonds.
293 citations
TL;DR: In this article, a 1-(2-Hydroxyl-ethyl)-imidazolium-based ionic liquids (HEIMX, X = Cl, Br, I), which have both acidic and basic characteristics, were covalently anchored onto a highly cross-linked polystyrene resin.
261 citations
TL;DR: In this article, a thermodynamic scheme representing the atom transfer radical polymerization (ATRP) equilibrium as the formal sum of equilibria involving carbon−halogen bond homolysis and three additional distinct thermodynamic contributions related to the catalyst is rigorously evaluated.
Abstract: A thermodynamic scheme representing the atom transfer radical polymerization (ATRP) equilibrium as the formal sum of equilibria involving carbon−halogen bond homolysis and three additional distinct thermodynamic contributions related to the catalyst is rigorously evaluated. The reduction/oxidation of both the metal complex and the halogen atom, and the affinity of the higher oxidation state of the catalyst for halide anions (or “halidophilicity”), are measured. The validity and self-consistency of the model are verified by independently measuring, computing, or calculating the overall ATRP equilibrium constant and all four contributing equilibrium constants for one catalyst/alkyl halide combination in acetonitrile. As a thorough demonstration of the value and effectiveness of the scheme, the different equilibrium constants were measured or calculated in 11 different organic solvents, and a comparison of their values was used to both understand and predict catalyst activity in ATRP with high accuracy. The ...
196 citations
TL;DR: Comparison with literature data suggests that the activation entropies might be used as indicators distinguishing between heterolytic and homolytic cleavage of the peroxo bond in the redox reactions of HSO(5)(-).
Abstract: The kinetics of the redox reactions of the peroxomonosulfate ion (HSO(5)(-)) with iron(II), vanadium(IV), cerium(III), chloride, bromide, and iodide ions were studied. Cerium(III) is only oxidized upon illumination by UV light and cerium(IV) is produced in a photoreaction with a quantum yield of 0.33 +/- 0.03. Iron(II) and vanadium(IV) are most probably oxidized through one-electron transfer producing sulfate ion radicals as intermediates. The halide ions are oxidized in a formally two-electron process, which most likely includes oxygen-atom transfer. Comparison with literature data suggests that the activation entropies might be used as indicators distinguishing between heterolytic and homolytic cleavage of the peroxo bond in the redox reactions of HSO(5)(-).
189 citations
TL;DR: In this article, the authors used UV-Vis spectrophotometry to identify and measure the thermodynamic properties of Au(III) aqueous complexes with chloride, bromide and hydroxide.
172 citations
TL;DR: The simulations revealed that sodium is attracted to the headgroup region with its concentration being maximal in the vicinity of the phosphate groups, this effect being likely underestimated within the present nonpolarizable force field.
Abstract: By means of molecular dynamics simulations with an all-atom force field, we investigated the affinities of alkali cations and halide anions for the dioleoylphosphatidylcholine lipid membrane in aqueous salt solutions In addition, changes in phospholipid lateral diffusion and in headgroup mobility upon adding NaCl were observed using fluorescence spectroscopy The simulations revealed that sodium is attracted to the headgroup region with its concentration being maximal in the vicinity of the phosphate groups Potassium and cesium, however, do not preferentially adsorb to the membrane Similarly, halide anions do not exhibit a strong affinity for the lipid headgroups but merely compensate for the positive charge of the sodium countercations Nevertheless, larger halides such as bromide and iodide penetrate deeper into the headgroup region toward the boundary with the hydrophobic alkyl chain, this effect being likely underestimated within the present nonpolarizable force field Addition of alkali halide salts modifies physical properties of the bilayer including the electronic density profiles, the electrostatic potential, and the area per lipid headgroup
160 citations
TL;DR: It is shown that PtI(4) is an effective Lewis acid catalyst for the activation of terminal alkynes for hydride attack and subsequent C-C bond formation and that the activity of neutral platinum salts can be modulated by the halide ligands.
Abstract: We report a catalytic intramolecular coupling between terminal unactivated alkynes and sp3 C−H bonds via through-space hydride transfer (HT-cyclization of alkynes). This method enables one-step preparation of complex heterocyclic compounds by α-alkenylation of readily available cyclic ethers and amines. We show that PtI4 is an effective Lewis acid catalyst for the activation of terminal alkynes for hydride attack and subsequent C−C bond formation. In addition, we have shown that the activity of neutral platinum salts (PtXn) can be modulated by the halide ligands. This modulation in turn allows for fine-tuning of the platinum center reactivity to match the reactivity and stability of selected substrates and products.
154 citations
TL;DR: The presence of LiCl considerably facilitates the insertion of magnesium into various aromatic and heterocyclic bromides and directing groups such as -OPiv, -OTs, -N(2)NR(2), or -OAc orient the zinc insertion to the ortho-position, while the reaction with Mg/LiCl/ZnCl leads to regioselective insertion into the para-carbon-bromine bond.
Abstract: The presence of LiCl considerably facilitates the insertion of magnesium into various aromatic and heterocyclic bromides. Several functional groups, such as -OBoc, -OTs, -Cl, -F, -CF(3), -OMe, -NMe(2), and -N(2)NR(2), are well tolerated. The presence of a cyano group leads in some cases to competitive reduction of the organic halide to the corresponding ArH compound. The presence of sensitive groups such as methyl or ethyl ester is tolerated upon in situ trapping of the intermediate magnesium reagent with ZnCl(2). This method can also be applied to the preparation of functionalized benzylic zinc reagents from benzylic chlorides. In the case of di- or tribromoaryl derivatives, directing groups such as -OPiv, -OTs, -N(2)NR(2), or -OAc orient the zinc insertion (Zn/LiCl) to the ortho-position, while the reaction with Mg/LiCl or Mg/LiCl/ZnCl(2) leads to regioselective insertion into the para-carbon-bromine bond. Large-scale experiments (20-100 mmol) for all of the metalation procedures are described.
154 citations
TL;DR: Silica-supported 4-pyrrolidinopyridinium iodide was prepared by quaternization of 4 pyrrolidine with silica supported alkyl iodide as mentioned in this paper.
146 citations
TL;DR: An overview of the structural chemistry of silver(I) coordination complexes can be found in this paper, where the main discussion is on the halide complexes (F−, Cl−, Br−, I−).
TL;DR: In this paper, the triplet state benzophenone and halide anion species (Cl, Br and I) were studied by laser flash photolysis (at 355 nm) in aqueous solutions at room temperature.
Abstract: The interactions between triplet state benzophenone and halide anion species (Cl , Br and I have been studied by laser flash photolysis (at 355 nm) in aqueous solutions at room temperature. The decay of the triplet state of benzophenone was followed at 525 nm. Triplet lifetime measurements gave rate constants, k q (M −1 s ), close to diffusion controlled limit for iodide (~8×10 9 M −1 s ), somewhat less for bromide (~3×10 8 M −1 s ) and much lower for chloride ( 6 M −1 s ). The halide (X − ) quenches the triplet state; the resulting product has a transient absorption at 355 nm and a lifetime much longer than that of the benzophenone triplet state, is formed. This transient absorption feature matches those of the corresponding radical anion (X 2 ). We therefore suggest that such reactive quenching is a photosensitized source of halogen in the atmosphere or the driving force for the chemical oxidation of the oceanic surface micro layer.
TL;DR: In this paper, the ruthenium-catalyzed generation of hydrogen from formic acid was investigated in the presence of amines and halide additives, and it was shown that >330mL hydrogen/h is generated in presence of [RuCl 2 (benzene)] 2 /dppe and N, N -dimethyl-n -hexylamine.
TL;DR: A highly enantioselective hydrogenation of the HX salts (X= Cl, Br, and I) of various 2aryl-substituted quinolines by using cationic dinuclear iridium complexes with [(4,4’-bi-2,2-difluoro-1,3-benzodioxole), which demonstrates an unexpected halide effect.
Abstract: Asymmetric hydrogenation by using chiral transitionmetal complexes represents one of the cleanest and most environmentally benign processes available for producing optically pure organic compounds. Currently, a wide variety of chiral compounds with outstanding levels of enantioselectivity has been synthesized by reduction of C=C, C= O, C=N, and, more recently, heteroaromatics compounds. Among heteroaromatics, 2-substituted quinolines have been targeted because optically active 2-substituted-1,2,3,4-tetrahydroquinoline derivatives are key components of many bioactive natural products and drugs. In contrast with the successful asymmetric hydrogenation of 2alkyl-substituted quinolines catalyzed by chiral iridium complexes with an iodide source or iodine, which dramatically enhances both catalytic activity and enantioselectivity, only limited success has been achieved in the catalytic hydrogenation of 2-aryl-substituted quinolines. So far, the only known examples used 2-phenylquinoline as a unique model substrate. The first example of catalytic hydrogenation of 2phenylquinoline (72 % ee (enantiomeric excess)), described by Zhou and co-workers, is based on an [IrACHTUNGTRENNUNG(cod)Cl]2/ MeO-biphep/I2 (cod=1,5-cyclooctadiene; MeO-biphep = 6,6’-dimethoxy-2,2’-bis(diphenylphosphino)-1,1’-biphenyl) catalytic system that was recently improved to 80 % ee with a moderate yield of 41 % by using benzyl chloroformate as an activating agent, although this required an additional deprotection step on the resulting carbamate. In recent years, only a few examples of the catalytic hydrogenation of 2-phenylquinoline have been reported with ee values up to 88 %. We describe herein a highly enantioselective hydrogenation of the HX salts (X= Cl, Br, and I) of various 2aryl-substituted quinolines by using cationic dinuclear iridium complexes with [(4,4’-bi-2,2-difluoro-1,3-benzodioxole)-5,5’-diyl]bis(diphenylphosphine) (difluorphos), which demonstrates an unexpected halide effect in which iridium complexes with chloro and bromo ligands serve as better catalysts than an iodo–iridium complex. The present catalyst was also effective for the hydrogenation of 2-alkyl-substituted quinolinium salts, which shows the high versatility of this new catalyst system. Furthermore, this system was applied to a formal asymmetric synthesis of selective estrogen receptor modulator (SERM) 6-hydroxy-2-(4-hydroxyphenyl)-1-{4[2-(pyrrolidin-1-yl)ethoxy]-benzyl}-1,2,3,4-tetrahydroquinoline (1) by asymmetric hydrogenation of the HCl salt of 6-methoxy-2-(4-methoxyphenyl)quinoline (2·Cl) as a key step. We recently developed cationic dinuclear triply halogenbridged iridium complexes [{Ir[(S)-diphosphine](H)}2 ACHTUNGTRENNUNG(mX)3]X (3–8 ; X=Cl, Br, and I) (Figure 1), which were conveniently prepared by adding excess aqueous HX to a mixture of [{IrCl ACHTUNGTRENNUNG(coe)2}2] (coe =cyclooctene) and the required chiral diphosphine ligand in toluene at room temperature. Thus, we first examined the asymmetric hydrogenation of 2-phenylquinolinium salts 9·X (X=Cl, Br, and I) promoted by Ir–binap complex (S)-3·X. Each reaction was conducted at 30 8C under hydrogen (30 bar) with 2 mol % of Ir complex in THF followed by a basic workup (Table 1, en[a] H. Tadaoka, T. Nagano, Prof. Dr. T. Ohshima, Prof. Dr. K. Mashima Department of Chemistry Graduate School of Engineering Science, Osaka University Toyonaka, Osaka 560-8631 (Japan) Fax: (+81) 6-6850-6245 E-mail : ohshima@chem.es.osaka-u.ac.jp mashima@chem.es.osaka-u.ac.jp [b] D. Cartigny, Dr. T. Gosavi, Dr. T. Ayad, Prof. Dr. J.-P. GenÞt, Dr. V. Ratovelomanana-Vidal Laboratoire Charles Friedel, UMR CNRS 7223 Ecole Nationale Sup rieure de Chimie de Paris 11 rue P. et M. Curie 75231 Paris cedex 05 (France) Fax: (+33) 144-071-062 E-mail : virginie-vidal@enscp.fr Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/chem.200901477.
TL;DR: The copper(I) bromide/1-(5,6,7,8,tetrahydroquinolin-8-yl)-2-methylpropan-1-one (CuBr-L3) combination catalyzed the cross-coupling reactions between aryl or heteroaryl halides and aqueous ammonia with high yields to produce primary aromatic and heteroaromatic amines at room temperature or under mild conditions as mentioned in this paper.
Abstract: The copper(I) bromide/1-(5,6,7,8-tetrahydroquinolin-8-yl)-2-methylpropan-1-one (CuBr-L3) combination catalyzed the cross-coupling reactions between aryl or heteroaryl halides and aqueous ammonia with high yields to produce primary aromatic or heteroaromatic amines at room temperature or under mild conditions.
TL;DR: In this article, a protocol for the copper-catalyzed C-S bond formation between aryl, alkyl, or heteroaryl thiols and hetero-hexanecarboxylate halides is reported.
TL;DR: Time-resolved extinction spectroscopy is employed to study the reaction kinetics in the shape-conversion reaction involving halide ions and shows that the halide ion etching reaction can be considered as a pseudo-first-order reaction.
Abstract: Time-resolved extinction spectroscopy is employed to study the reaction kinetics in the shape-conversion reaction involving halide ions (including Cl−, Br− and I−) etching (sculpturing) silver nanoplates. A series of time-resolved extinction spectra are obtained during the in situetching process and the evolution of surface plasmon resonance (SPR) of the silver nanoparticles is analyzed. Spectral analysis indicates that the conversion of nanoprisms starts simultaneously with the emergence of nanodisks when the halide ions are added. The etching rate of different halide ions is evaluated through the in-plane dipole resonance peak intensity of silver nanoplates vs. the reaction time (dI/dt). The relationship between the etching rate and the halide ion concentration shows that the halide ion etching reaction can be considered as a pseudo-first-order reaction. The effect of different halide ions on the shape-conversion of silver nanoplates is compared in detail. The activation energy of the etching reaction is calculated, which indicates that the etching ability of different halide ions is on the order of Cl− < I− < Br−.
Patent•
14 May 2009
TL;DR: A nitride-based deep red phosphor having at least one of the following features: 1) an oxygen content less than about 2 percent by weight, and 2) a halogen content.
Abstract: A nitride-based deep red phosphor having at least one of the following features: 1) an oxygen content less than about 2 percent by weight, and 2) a halogen content. Such phosphors are useful in the white light illumination industry, which utilizes the so-called "white LED." The selection and use of a rare earth halide as a raw material source of not only the activator for the phosphor, but also the halogen, is a feature of the present embodiments. The phosphors have the general formula MaMbBc(N,D):Eu2+, where Ma is a divalent alkaline earth metal such as Mg, Ca, Sr, Ba; Mb is a trivalent metal such as Al, Ga, Bi, Y, La, and Sm; and Mc is a tetravalent element such as Si, Ge, P, and B; N is nitrogen, and D is a halogen such as F, Cl, or Br. An exemplary compound is CaAlSi(N1-xFx): Eu2+.
TL;DR: DFT studies on the mechanism support the occurrence of a catalytic cycle involving transmetalation of the alkyl zinc halide to Ni(I) followed by oxidative addition of the haloarene and C-C reductive elimination.
Abstract: Optimal conditions for a general Ni-catalysed Negishi cross-coupling of alkyl zinc halides with aryl, heteroaryl and alkenyl halides have been determined. These conditions allow the reaction to take place smoothly, with low catalyst loading, and in the presence of a wide variety of functional groups to afford products in good yields at room temperature. DFT studies on the mechanism support the occurrence of a catalytic cycle involving transmetalation of the alkyl zinc halide to Ni 1 followed by oxidative addition of the haloarene and C—C reductive elimination.
TL;DR: In this paper, the reduction of a series of organic halides, including both aromatic and aliphatic compounds, has been investigated in acetonitrile at glassy carbon (GC) and silver electrodes.
Abstract: The reductive cleavage of a series of organic halides, including both aromatic and aliphatic compounds, has been investigated in acetonitrile at glassy carbon (GC) and silver electrodes. Ag exhibits extraordinary electrocatalytic activities for the reduction of most of the investigated halides. During the reductive cleavage of a carbon–halogen bond, electron transfer (ET) and bond breaking may occur either in a single step or in two distinct steps. The compounds examined in this study are representative of both dissociative electron transfer (DET) mechanisms. In general a link between the DET mechanism and electrocatalysis at Ag is observed for the whole set of data. There is no catalysis at all when the ET involves a substituent that gives a stable radical anion. Furthermore, there is no catalysis for all aromatic chlorides. Instead, a remarkable electrocatalysis is observed for all compounds undergoing a concerted DET mechanism, regardless of the nature of the halogen atom.
TL;DR: In this paper, the presence of seawater concentrations of chloride and bromide ions enhanced absorbance photobleaching reaction rates by approximately 40% regardless of DOM source or the presence or absence of carbonate ions.
TL;DR: It is concluded that with the highly active carbon-supported gold-palladium catalysts these additives are not required and that therefore this system presents the potential for the direct synthesis of hydrogen peroxide to be operated using green process technology.
Abstract: The effect of halide and acid addition on the direct synthesis of hydrogen peroxide is studied for magnesium oxide- and carbon-supported bimetallic gold-palladium catalysts. The addition of acids decreases the hydrogenation/decomposition of hydrogen peroxide, and the effect is particularly pronounced for the magnesium oxide-supported catalysts whilst for carbon-supported catalysts the pH requires close control to optimize hydrogen peroxide synthesis. The addition of bromide leads to a marked decrease in the hydrogenation/decomposition of hydrogen peroxide with either catalyst. These effects are discussed in terms of the structure of the gold-palladium alloy nanoparticles and the isoelectric point of the support. We conclude that with the highly active carbon-supported gold-palladium catalysts these additives are not required and that therefore this system presents the potential for the direct synthesis of hydrogen peroxide to be operated using green process technology.
TL;DR: In this article, the scintillation properties of many Ce3+ doped halide compounds studied during the past two decades with the aim to find new relationships between scintillillation performance and materials properties.
Abstract: This work reviews the scintillation properties of many Ce3+ doped halide compounds studied during the past two decades with the aim to find new relationships between scintillation performance and materials properties. Three major types of compounds are reviewed; lanthanide trihalides LnX3, (pseudo)-elpasolites M2ALnX6 and ternary halides Am Lnn Xo where M and A are alkali cations, Ln is a rare earth cation and X is a halide anion. We will address the relationship of the emission wavelength of Ce3+ and its Stokes shift with the structure, type of anions, coordination number, band gap etc. A comparison between the observed absolute scintillation yield with the fundamental limits will be made. Scintillation losses due to thermal ionization processes and the relationship between Stokes shift, self absorption, and decay time lengthening are treated. Various trends will be identified that may guide us in the continuing quest for better scintillators. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
TL;DR: An efficient Ullmann-type reductive homocoupling of aryl, vinyl and heteroaryl halides can be promoted by an aldehyde in tetraalkylammonium ionic liquids under very mild reaction conditions, which opens the way to a new efficient method of Pd-catalysed dehydrogenation of carbonyl compounds.
Abstract: An efficient Ullmann-type reductive homocoupling of aryl, vinyl and heteroaryl halides can be promoted by an aldehyde in tetraalkylammonium ionic liquids under very mild reaction conditions. This simple procedure generates symmetrical biaryls under relatively mild conditions. The ionic liquid is crucial for this process because it behaves simultaneously as a base, ligand and reaction medium. The role of the aldehyde is also discussed and a general mechanism for this unusual reaction is proposed. These results open the way to a new efficient method of Pd-catalysed dehydrogenation of carbonyl compounds.
TL;DR: In this paper, the supramolecular organization in six solid assemblies involving iodo-and bromoperfluoroarene derivatives is described and single crystal X-ray analyses are performed.
TL;DR: In this paper, a copper-catalyzed synthesis of β-haloalkenyl sulfides or selenides was carried out by adding dichalcogenides and tetrabutylammonium halides to internal alkynes.
Patent•
08 Apr 2009Abstract: Disclosed is a method for preparing a compound of Formula 1 wherein Q and Z are as defined in the disclosure comprising distilling water from a mixture comprising a compound of Formula 2, a compound of Formula 3, a base comprising at least one compound selected from the group consisting of alkaline earth metal hydroxides of Formula 4 wherein M is Ca, Sr or Ba, alkali metal carbonates of Formula 4a wherein M1 is Li, Na or K, 1,5-diazabicyclo[4.3.0]non-5-ene and 1,8-diazabicyclo[5.4.0]undec-7-ene, and an aprotic solvent capable of forming a low-boiling azeotrope with water. Also disclosed is a method for preparing a compound of Formula 2 comprising (1) forming a reaction mixture comprising a Grignard reagent derived from contacting a compound of Formula 5 wherein X is Cl, Br or I with magnesium metal or an alkylmagnesium halide in the presence of an ethereal solvent, and then (2) contacting the reaction mixture with a compound of Formula 6 wherein Y is OR11 or NR12R13, and R11, R12 and R13 are as defined in the disclosure. Further disclosed is a method for preparing a compound of Formula 7 wherein Q and Z are as defined in the disclosure, using a compound of Formula 1 characterized by preparing the compound of Formula 1 by the method disclosed above or using a compound of Formula 1 prepared by the method disclosed above.
TL;DR: In this article, Ionic liquid functionalized mesoporous silicas (IFMSs) were prepared from the coupling of 1-(triethoxysilylpropyl)-3-n-alkylimidazolium halides with tetraethyl orthosilicate (TEOS) through template-free condensation under strong acidic conditions.
Abstract: Ionic liquid functionalized mesoporous silicas (IFMSs) were prepared from the coupling of 1-(triethoxysilylpropyl)-3-n-alkylimidazolium halides with tetraethyl orthosilicate (TEOS) through template-free condensation under strong acidic conditions. Optimal synthesis conditions and maximum incorporation of the active sites were achieved through varying the parameters of the co-condensation method. The obtained amorphous silica having 0.20–0.93 mmol of RIm+X− groups showed a surface area between 477 and 672 m2/g with pore sizes from 3.2 to 7.8 nm. The materials synthesized under various TEOS pre-hydrolysis had larger surface areas, pore volumes, and average pore diameters than those synthesized without pre-hydrolysis. FT-IR, TG/DTG (thermogravimetry/differential thermogravimetry), and solid-state NMR showed that all the immobilized ionic liquid (IIL) groups were incorporated without affecting the organic moieties. Chemical fixation of carbon dioxide was studied at various carbon dioxide pressures by correlating reactivity with various parameters such as surface area, pore volume, pore size, percentage of active sites, type of counter ion, and length of the organic moiety extending from the alkyl halide.
TL;DR: A cobalt-catalyzed cross-coupling of aryl halides with 2-chloropyrimidines or 2- chloropyrazines is reported in satisfactory to high yields and represents a practical and interesting alternative to previously known methods for the synthesis of 2-aryldiazines.
Abstract: A cobalt-catalyzed cross-coupling of aryl halides with 2-chloropyrimidines or 2-chloropyrazines is reported in satisfactory to high yields. The key step of this procedure is the formation of aromatic organozinc reagents and their coupling with 2-chlorodiazines using the same cobalt halide as catalyst and Zn dust under mild reaction conditions. This new cobalt-catalyzed coupling reaction represents a practical and interesting alternative to previously known methods for the synthesis of 2-aryldiazines.
Patent•
16 Jun 2009TL;DR: In this article, a method for converting a carbohydrate to a furan in a polar aprotic solvent in the presence of a chloride, bromide, or iodide salt or a mixture thereof was presented.
Abstract: A method for converting a carbohydrate to a furan in a polar aprotic solvent in the presence of a chloride, bromide, or iodide salt or a mixture thereof and optionally in the presence of an acid catalyst, a metal halide catalyst and/or an ionic liquid (up to 40 wt %). The method can be employed in particular to produce furfural or 5-hydroxymethylfurfural.