bluuebunny/crossref_metadata_2025_split huggingface dataset:
Generation and Reactions of Carbanions from Dialkylamino (Methylthio) Acetonitriles
Authors: Jonczyk Andrzej , Owczarczyk Zbysław , Makosza MieczysŁaw , Winiarski Jerzy 
Published: September 2010

AbstractDialkylamino (methylthio) acetonitriles 1 have been prepared by two independent pathways. The carbanions generated from 1 in various base/solvent systems reacted with alkyl halides or electrophilic alkenes to give unstable products 2 and 5 respectively. These products were transformed into amides 3 or acids 4 and 6. On the other hand, carbanions from 1 with ethyl maleinate or ω‐nitrostyrene afforded products of aliphatic vicarious nucleophilic substitution 7 while with 1‐nitronaphthalene, the product of aromatic vicarious nucleophilic substitution 8.
Enantioselective Catalysis, 341) Phosphines with (s)‐2‐Methylbutyl. Substituents and Their Ph Complexes ‐ use in Enantioselective Catalysis
Authors: Brunner H. , Leyerer H. 
Published: September 2010

Abstract(S)‐2‐methylbutyl Grignard, prepared from (S)‐(‐)‐2‐methylbutan‐1‐ol via (S)‐(+)‐2‐methylbutyl‐1‐bromide, was used for the synthesis of phosphines 1‐4, containing (S)‐2‐methylbutyl substituents. In the reaction with [Rh(cod)Cl]2, phosphines 1 and 2 give the neutral complexes 5 and 6 of the type Rh(cod)(L)Cl, whereas phosphines 3 and 4 give the salts 7 and 8 of the type [Rh(cod)L2]PF6. The isolated complexes 5‐8 and the in situ systems [Rh(cod)Cl]2/1‐4 lead to optical inductions of up to 15 a ce in the anantioselective hydrogenation of (Z)‐α‐N‐acetamidocinnamic acid and of up to 4.5% in the enantioselective hydrosilylation of acetophenons with diphenylsilane.
Bipositive Metal Complexes of N1 ‐(4‐Chlorophenyl)‐N4‐(3,5‐Dinitrobenzoyl) Thiosemicarbazide
Authors: Dwivedi D. K. , Agarwala B. V. , Dey A. K. 
Published: September 2010

AbstractPolymeric coordination complexes of the type (ML.2H2O)n, where M(II) ‐ Mn, Fe, Ni, Cu or Zn and L = N1 ‐(4‐chlorophenyl)‐N4‐(3,5‐dinitrobenzoyl)thiosemicarbazide have been synthesised and characterised by microanalytical, I. R., magnetic, D. R. S. and thermal analysis. The IR spectra indicate tetradentate ligand coordination through the enolic oxygen, thioenolic sulphur and the nitrogen atom of the CN group. The metal ion is the bridging unit between the donor sites of the ligand molecule, and it is likely that a polymeric chain grows through consecutive ligand‐metal links.
Crystal Structure and Conformation of Short Linear Peptides. Part V. N‐Benzyloxycarbonyl‐Glycyl‐Glycyl‐L‐Proline
Authors: Wu S. , Tinant B. , Declercq J. P. , van Meerssche M. 
Published: September 2010

AbstractC17H21N3O6, Mr = 363.37, monoclinic, P21, a = 17.774(6), b = 10.105(3), c = 4.963(1)Å, β = 92.30(2)°, V = 890.7(5)Å1, Z = 2, Dx = 1.36 g. cm−3, MoKα, λ = 0.71069 Å, μ = 1.12 cm−1, F(000) = 384, T = 291K, R = 0.056 for 717 observed reflections. The (φ, Ψ) values of (81°, 35°), (‐174°, 169°) and (‐79°, 164°) define a left‐handed α‐helix conformation at Gly(1), an extended form at Gly(2) and a collagen‐like conformation at terminal Pro respectively. The pyrrolidine ring has a C8‐Cβ‐exo conformation.
Evidence for a Presumed Mechanism of the Reaction of 2‐Benzoyl 1, 2‐Dihydro Isoquinaldonitrile Hydrofluoroborate on Methyl Methacrylate
Authors: Schmitt Gerard , Fathi Toufik , Cerutti Ernest , Laude Bernard 
Published: September 2010

AbstractThe previously suggested mechanism of the condensation‐rearrangement reaction of Reissert compound hydrofluoroborate salts with reactive olefins was reexamined in the case of methyl methacrylate. Addition of triethylamine to the reaction medium leads to isolate a presumed intermediate.
Synthesis and Spectroscopic Study of a Series of Diarylacetylene Dicobalt Hexacarbonyl Complexes. AOSC ‐TW
Authors: Pepermans Henri , Willem Rudolph , Hoogzand Cornelis 
Published: September 2010

AbstractA series of methyl, methoxy and trimethylsilyl substituted diphenylacetylenes was reacted with Co2(CO)8, giving the corresponding (diarylacetylene) Co2(CO)6 complexes. The predominance of the steric effect of the substituents in these reactions was established. The complexes were studied by IR, MS, 13C NMR, 1H NMR and UV‐visible spectroscopy.
Synthesis and Thermolysis of Some N‐Hydroximoyl ‐ and N‐Hydrazonoylazoles
Authors: Plenkiewicz Jan , Zdrojewski Tadeusz 
Published: September 2010

AbstractThe reactions of nitrile oxides or nitrile imines with pyrazole, imidazole, 1,2,3‐ and 1,2,4‐triazole or tetrazole derivatives yield the appropriate N‐hydroximoyl‐ or N‐hydrazonoylazoles. Thermolysis of 1‐hydroximoyltetrazoles, depending on the nature of the substituents in the tetrazole ring, yields 1,2,4‐oxadiazoles or 5‐amino‐l,2,4‐oxadiazoles upon hydrazoic acid or nitrogen evolution. Under similar conditions, 1‐hydazonoyltetrazoles give 1,2,4‐triazoles or 5‐amino‐1,2,4‐triazoles while 2‐hydrazonoyltetrazoles decompose to the dihydro‐1,2,4,5‐tetrazine derivatives.
Tungsten Carbonyl Precursors in Catalyzed Olefin Metathesis I. Photochemically Induced Olefin Metathesis by the W(CO)6/TiX4 Catalytic System
Authors: Vanwijnsberghe F. M. G. , Vanderyse L. , Bossuyt A. R. , Verdonck L. , van Der Kelen G. P. , Gent Rijksuniversiteit 
Published: September 2010

AbstractThe catalytic and spectroscopic properties of the photochemically activated metathesis catalyst system W(CO)6/TiX4/hx∼︁ (X = Cl, Br, I) have been studied. All evidence indicates a high resemblance with the chemically activated W(CO)6‐XLX/RAlCl2/O2 systems. Irradiation of the W(CO)6/TiX4 precursor solution causes loss of CO ligands and has the same promoting effect as O2 for chemically activated systems.
Crystal Structure of 3‐Tert‐Butylimino‐2,3‐Dihydroimidazo [1, 2‐a]Pyridin‐2‐One
Authors: L'abbé Gerrit , Meervelt Luc Van , Brems Patrick , Declercq Jean‐Paul 
Published: September 2010

AbstractThe crystal structure of 3‐tert‐butylimino‐2,3‐dihydroimidazo[1,2‐a]pyridin‐2‐one (C11H13N3O, Mr = 203.25, a = 9.247(1), b = 11.947(1), c = 9.736(1) Å, V = 1075.6(2) Å3, space group P212121, Z = 4, Dx = 1.26 g. cm−3, F(000) = 432) has been determined by single crystal X‐ray diffraction techniques (CuKα, T = 291K) and refined to R = 0.034 for 1867 observed reflections. The exocyclic imino function on the planar imidazo[1,2‐a]pyridine ring adopts the E‐configuration.
Experiences in Z‐Deprotection. Simple Preparations of Z‐His and diz‐His
Authors: Anteunis M. J. O. , Becu Chr. , Becu F. , Reyniers M. ‐F. 
Published: September 2010

AbstractA systematic investigation about the possibilities of removing benzyloxycarbonyl groupings in some model peptides acids that resist easy deprotection, have led to some interesting and efficient modified procedures. One‐pot synthetic methods for Zα‐His‐OH and Zα, ZIm‐His‐OH are also reported.
A New Version of Hugershoff Synthesis
Authors: Garin Javier , Guillen Carmen , Melendez Enrique , Merchan Francisco L. , Orduna Jesús , Tejero Tomás 
Published: September 2010

AbstractN‐halosuccinimide/sulfuric acid is a new, highly efficient reagent for the oxidation of cyclic thioureas to the corresponding 2‐aminobenzothiazole derivatives.
Synthèses Asymétriques Potentielles Impliquant la Réaction “Ene”
Authors: Ben Hassine B. , Gorsane M. , Pecher J. , Martin R. H. 
Published: September 2010

AbstractRacemic “ene” syntheses have been carried out to evaluate the potentiality, in asymmetric syntheses, of the corresponding optically active inducers. The (dl)‐crotonates 5 to 8 were prepared from (dl)‐hydroxyheptahelicene 1 and the sec. alcohols 2, 3 and 4. Chemical yields are shown in table 1 (85–94%).These (dl)‐crotonates underwent the “ene” reaction with cyclohexene in the presence of SnCl4 to give the corresponding diastereomeric (dl)‐esters 9, 10, 11 and 12, with respectively ∼︁100, 48, 70 and ∼100% diastereomeric excesses.
Diesel Hydrotreating With NiMo/Al2O3 Catalyst
Authors: Galiasso R. , Rodríguez E. 
Published: September 2010

AbstractThe hydrotreatment of two cracked Diesel fractions have been studied using fresh and on “stade state” catalysts at different pressure and operating conditions. The effect of temperature, pressure, type of feedstock on catalyst activity and selectivity were evaluated. Physicochemical analysis of the catalyst was performed in order to investigate the changes in the active phases. It was demonstrated that activity and selectivity change during the initial deactivation of fresh catalyst by coke deposition and active center modification. The hydrogenation activity decreases more than desulfurization which reduces the quality of products obtained. The higher the pressure the lower the loss. It was also observed that more than 70% of accessible metal content in surface is lossed. Additionally, acidity and average pore diameter are increased by operation. Some structural modifications of active phase are postulated.
Studies of Molybdena‐Alumina Catalysts XIII no Adsorption and Sh Content of Sulfided Catalysts
Authors: Miciukiewicz J. , Zmierczak W. , Massoth F. E. 
Published: September 2010

AbstractA series of Mo/Al2O3 catalysts were prepared containing various levels of Mo, several different Al2O3 supports, and by different solution pH's. Sulfided catalysts were characterized by NO chemisorption, SH content and thiophene HDS activity. Uptake of NO depended on the temperature of adsorption employed, and consequently an absolute number of adsorption sites could not be determined. Also, correction for NO adsorption on the support was needed to obtain values representative of the MoS2 species present. Assuming NO adsorbs at edge sites of the MoS2 slabs, it was found that the size of the MoS2 slabs was affected by the nature of the Al2O3 support but only slightly by the pH of the impregnating solution. Residual SH content roughly correlated with net NO adsorption. HDS activity was roughly proportional to net NO adsorption and to residual SH content. Significant deviations, however, were observed, indicating that catalytic activity is not precisely related to either.
Formation of Promoted Sites From Ni(CO)4 Decomposition on Sulfided Mo/Al2O3 Catalysts. A Comparative Ir Study With Conventional Ni‐Mo/Al2O3 Catalysts, Using CO as a Probe Molecule
Authors: Angulo M. , Maugé F. , Duchet J. C. , Lavalley J. C. 
Published: September 2010

AbstractIR spectroscopy has been used to characterize samples prepared by decomposition of nickel carbonyl over a MoS2/γ‐Al2O3 based catalyst. IR spectra of adsorbed CO indicates a much higher degree of promotion than for the conventional Ni‐Mo/Al2O3 catalyst. The samples also readily catalyse the in‐situ transformation of piperidine into intermediate species yielding further pyridine. Chemical analysis leads to very low Ni content, indicating a delocalization of the electronic effects of the promoter over the whole MoS2 slab. Results are consistent with the promoted sites pictured as highly reduced sites.
Solvent influence on the dipole moment and charge transfer effect in the 2, 6‐Lutidine. I2 Complex
Authors: Pawelka Z. 
Published: September 2010

AbstractThe dipole moments of the CT complex between 2, 6‐lutidine and I2 have been measured in cyclohexane, CCl4, benzene, trichloroethylene, chloroform and chlorobenzene. The fractions of charge transferred from donor to acceptor have been estimated. It has been stated that the contribution of the dative structure F1 increases with an increase in the solvent activity and varies linearly with the frequency shift Δv/v of the visible iodine absorption band. The solvent influence on F1 and Δv/v has been rationalized in terms of correlations with empirical parameters of the solvent polarity which are related to their polar and electron‐accepting properties.
Enantiomeric quantifications of amino acids through their Na‐Acyl amides by gas chromatography
Authors: Hosten N. , Anteunis M. J. O. 
Published: September 2010

AbstractApparent separation factors of 1.1 or higher on Chirasil Val III can be obtained for Na‐acyl N‐alkyl aminoacid amides allowing the use of short capillary gas chromatographic columns. A clean derivatization protocol without racemization is described, proceding through the NCA derivatives that are prepared from “in situ” silylated amino acids with trimethylsilyl cyanide.
Functionalisation of isophorone involving polychlorination part III. Synthesis of hydroxycyclohexadienone aldehydes from a pentachloroisophorone by base‐induced acetolysis
Authors: De Buyck L. , De Pooter H. , Schamp N. 
Published: September 2010

AbstractThe reaction of 2, 6, 6‐trichloro‐3‐dichloromethyl‐5, 5‐dimethyl‐2‐cyclohexenone (1) with triethylamine in acetic acid containing acetic anhydride afforded 2‐acetoxy‐6‐diacetoxymethyl‐3‐chloro‐4, 4‐dimethyl‐2, 5‐cyclohexadienone (2) in 49% yield (47% isolated). As a side reaction the isomeric 2,4‐cyclohexadienone 5 or mixtures of three of its precursors were formed in 30‐46% yield. The formation of an aromatic side product 8 (4‐23%) was suppressed at low initial reaction temperature. Acid catalyzed hydrolysis of 2 and 5 afforded the isomeric hydroxycyclohexadienone aldehydes 4 resp. 6. In aqueous bicarbonate solution 6 was readily converted into a dimer for wich the pentacyclic structure 29 is proposed, containing two different cyclobutanone rings. The reaction mechanisms are discussed in the context of related substitution reactions.
Conclusive evidence against a cyclobutadiene intermediate in the cyclotrimerization of diarylacetylene using the diarylacetylene hexacarbonyl dicobalt complex as catalyst
Authors: Pepermans Henri , Willem Rudolph , Gielen Marcel , Hoogzand Cornelis 
Published: September 2010

AbstractTo decide whether the cyclotrimerization of diarylacetylene with diarylacetylene hexacarbonyl dicobalt as catalyst, proceeds via a cyclobutadiene intermediate, two experiments were performed, both relying on the experimentally verified hypothesis that a 3‐methoxyphenyl ring can be considered as an ideally chemically labelled phenyl ring : (1) the co‐cyclotrimerization of diphenylacetylene with bis(3‐methoxyphenyl)acetylene, and (2) the cyclotrimerization of 1‐(3‐methoxyphenyl)‐2‐phenylacetylene. Analysis of the resulting meta methoxy substituted hexaphenylbenzenes using our chemical shift model, is for both experiments conclusive against the involvement of a cyclobutadiene intermediate.
Validation Par Spectroscopie Rmn1H Des Paramètres Geométriques Du Dimère Phénolique Obtenus Par Calculs Cndo/2
Authors: Moreau Descoings M. C. , Goethals G. , Seguin J. P. , Doucet J. P. 
Published: September 2010

AbstractHydroxylic hydrogen chemical shifts of phenol are measured in carbon tetrachloride at different concentrations. We have also calculated by the C NDO/2 method, the electronic populations on the hydroxylic hydrogen and oxygen atom of the phenol dimer and monomer for optimized geometry. From the biparametric relationship relating the chemical shift to both hydroxylic hydrogen and oxygen electronic population, established in a previous work, we have calculated a theoretical shift for the dimer hydroxylic hydrogen. For each concentration, we have compared the experimental chemical shift with the calculated value obtained in using the dimer and monomer concentrations and the theoretical chemical shift for each proton. The good agreement between experimental and calculated value validates the optimized geometry of hydrogen bond complex and the biparametric relationship.
The synthesis of a Nγ‐phthalyl‐Nα‐methyl‐α, γ‐diaminobutyryl congener of virginiamycin S1
Authors: Anteunis M. J. O. , van Der Auwera C. , Vanfleteren L. , Borremans F. 
Published: September 2010

AbstractA synthesis of Z‐Thr1 ‐D‐Abu2 ‐Pro3 ‐MePhe4 ‐MeA2bu(γPht)5 ‐Phg6 ‐ (A2bu = α, γ‐diaminobutyric acid) is reported using the very efficient coupling agent BOP‐Cl (N, N'‐bis(3‐oxo‐2‐oxazolidinyl)phosphinic chloride) for imino acid peptide bond formation. The total yield is 11% for the 5 coupling steps and one lactonization. The final step was a cyclization between residues 5 and 6, after (i) first t‐Boc acidic deprotection with 85% HCOOH of the linear precursor Z‐Thr (Nα‐Boc‐Phg‐O‐)‐D‐Abu‐Pro‐MePhe‐MeA2bu(γPht)‐OBu followed by (ii) acidic saponification (Tfa) of the t‐Bu ester. This sequence was found to be a prerequisite, in view of the extreme lability of the 4–5 peptide bond under acidic conditions.
Cycloaddition De Quelques Diarylnitrilimines Sur Diverses Arylidene‐2 Indanones‐1. Régio‐ Et Diastéréochimies Des Spiropyrazolines Synthétisées
Authors: Kerbal Abdelali , Tshiamala Kabula , Vebrel Joäl , Lauds Barnard 
Published: September 2010

AbstractSpiropyrazolines have been synthetized by 1,3‐dipolar cycloaddition of some 2‐arylidene 1‐indanones with diarylnitrilimines. It is shown that ringclosure reaction is regiospecific, yielding stereohomogeneous spiropyrazolines in one step. The relative configuration and stereochemistry of the products have been determined by means of protonic magnetic resonance measurements.
Bop‐Cl mediated cyclization of a linear precursor of virginiamycin S. Contra indication for using HOBt as racemization suppressor
Authors: Anteunis M. J. O. , Sharma N. K. 
Published: September 2010

AbstractCyclization of a model linear hexapeptide (VS1, linear peptide, 1) was achieved at moderate temperature (‐15° to r. t.) in ≥80% yields in using BOP‐C1 [N, N'‐bis(2‐oxo‐3‐oxazolidinyl) phosphinic chloride] and BOP‐reagent [benzotriazolyloxy tris (dimethylamino) phosphonium hexafluorophosphate] as coupling reagents in one‐pot procedures. Stereomutation was high (∼︁40%). The addition of N‐hydroxybenzotriazole doubled the degree of epimerization. A rationale is offered in order to explain the enantiomeric induction. High dilution was necessary to avoid side products (dimer/trimer) formation. However, dilution does not effect the rate of cyclization considerably.
Cholest‐6‐EN‐11β, 19‐epoxy‐3β, 5α, 8α, 9α‐tetrol, a novel polyoxygenated steroid from the sponge dysidea tupha
Authors: Braekman J. C. , Daloze D. , Moussiaux B. , Vandevyver G. , Riccio R. 
Published: September 2010

AbstractCholest‐6‐en‐11β, 19‐epoxy‐3β, 5α, 8α, 9α‐tetrol(1), a new toxic polyoxygenated steroid, has been isolated from the sponge Dysidea tupha. Its structure has been determined on the basis of its spectral properties.
Tungsten carbonyl precursors in catalyzed olefin metathesis II. Homegeneous olefin Metathesis by the RnX3‐n SnW(CO)3π‐C5H5/iBuAlCl2/O2 System
Authors: Vanderyse L. M. , Verdonck L. , Bossuyt A. R. , van Wijnsberghe F. M. G. , van Der Kelen G. P. 
Published: September 2010

AbstractRnX3‐nSnW(CO)3Cp (R = Me, Ph; X = Cl) precursors activated by iBuAlCl2 in the presence of oxygen in an optimal 1 October 5 ratio, show high conversion rates and a good selectivity for the 2‐pentene metathesis. The conversion rates follow the sequence Ph3Sn‐ « Me3Sn‐ < Me2ClSn‐ < Cl3Sn‐ but the tin moiety has no significant effect on the stereoselectivity for cis‐2‐pentene. There are several indications for the occurrence of competitive and successive α‐ and β‐H elimination reactions in the generation of the active tungsten carbene species.
Structure Determination of Isoxazolidine Derivatives Obtained from (E)‐Unsaturated 5,10‐Seco‐steroidal Ketones
Authors: Tinant B. , Declercq J. P. , van Meerssche M. , Mihailovic M. Lj. , Lorenć Lj. , Rajković M. , Milovanović A. 
Published: September 2010

Abstract(E)‐Δ1 (10) ‐unsaturated 5‐oxo‐5,10‐seco‐steroids such as 1, react with hydroxylamine and N‐methylhydroxylamine to give stereospecifically isoxazolidine derivatives of type 2 and 3, respectively. The molecular structure of isoxazolidine 3a obtained from (E)‐3β‐acetoxy‐5,10‐seco‐cholest‐1 (10)‐en‐5‐one (la) and N‐methylhydroxylamine has been determined by X‐ray analysis.
Anchoring Substitution in Acyclic Fragments. A Topical Basis for Enhanced Diastereofacial Selection in the Diels‐Alder Reaction to Chiral Acrylates
Authors: De Corte Filip A. J. , De Clercq Pierre J. 
Published: September 2010

AbstractChiral acrylates 4a, 4b and 4c, derived from primary alcohols with a single stereogenic centre, were studied for possible diastereoface differentiation in their Lewis acid catalyzed Diels‐Alder reaction with cyclopentadiene. No relevant diastereomeric excess was observed for the tert‐butyl derived 4a. On the other hand, moderate but significant diastereomeric excesses (72‐76 %) resulted when the trityl derived acrylates 4b and 4c were used. The ability of enforcing a 1,3‐parallel orientation between the aryl shielding group and the acrylate moiety by incorporation of a tert‐butyl or trityl anchoring substituent in the connecting chain is qualitatively assessed by 1H NMR.
Convenient Method for the Preparation of 3‐(2‐Pyridyl Dithio) Propionic Acid N‐Hydroxy Succinimid Ester
Authors: Loccufier J. , Schacht E. 
Published: September 2010

AbstractA new efficient and simple method for the preparation of 3‐(2‐pyridyl dithio) propionic acid N‐hydroxy succinimid ester using diethyl azo dicarboxylate, is described.
Introduction of substituents into 5‐membered aza‐heteroaromatics
Authors: Begtrup Mikael 
Published: September 2010

AbstractWith emphasis on mono‐ and regio‐selectively, methods for introduction of substituents at nitrogen and carbon atoms of 5‐membered aza‐heteroaromatics have been developed. The methods involve application of activation and of assistant groups for direction and protection. Activation has been achieved by the use of quaternary azolium ions and azol‐N‐oxides as reactive intermediates. If necessary, the N‐oxides were further activated by alkylation or acylation.
Tungsten carbonyl precursors in catalyzed olefin metathesis. III. infrared study of RnCl3‐nSnW(CO)3π−C5H5derivatives and their interaction with iBuAlCl2and O2
Authors: Vanderyse L. M. , Haemers T. , Bossuyt A. R. , Verdonck L. , van Der Kelen G. P. 
Published: September 2010

AbstractThe LW(CO)3Cp (L = RnSnCl3‐n, H, Cl) derivatives and their interaction with iBuAlCl2and O2have been studied by i. r. spectroscopy.Mechanisms for the generation of the active tungsten‐carbene complex in the early stages of reaction are proposed.
A liposoluble cationic complex of Ru(II) based on 1,4,5,8‐tetra‐azaphenanthrene
Authors: Nasielski J. , Garcia Y Abeledo M. ‐L. , Nasielski‐Hinkens R. 
Published: September 2010

AbstractReacting 2,2‐dichlorododecanal with 1,2‐diamino‐4‐nitrobenzene in dioxane in the presence of a base gives a 46% yield of 2‐decyl‐6‐nitroquinoxaline, which after amination by hydroxylamine and reduction gave 5,6‐diamino‐2‐decylquinoxaline. This diamine, again with 2,2‐dichlorododecanal in dioxane and base, affords 2,6‐didecyl‐ and 2,7‐didecyl‐1,4,5,8‐tetraazaphenanthrene (2,7ddTAP); the latter ligand gives the hexane‐soluble Ru(2,7ddTAP)3(PF6)2.
Infrared emission spectroscopy in H2/F2 and CH4/F2 premixed flames
Authors: Vandooren J. , Vanpee M. 
Published: September 2010

AbstractThe infrared emission corresponding to the Δ v=1 transitions of the vibrationally excited HF (1 < =v< =3) has been recorded in rich premixed hydrogen‐fluorine and methanefluorine flames burning at various pressure (1.3–9 torr). The initial hydrogen and fluorine element content was identical in both CH4‐and H2‐ fluorine flames.The rational temperature profiles have been determined as well as in H2/F2 flames than in CH4/F2 ones. The analysis of the experimental data has put forward the occurrence of an equilibrated vibrational population relatively early in the burnt gases region of flames burning at pressures higher than 5 torr. From these evidences, profiles of the relative mole fractions of HF in its vibrationally excited states (1 < =v< =3) have been established in both series of flames. The absolute total concentrations of HF have been deduced by considering the Lewis number equals to one and therefore the absolute mole fraction profiles of the individual vibrationally excited HF (0 < =v< =3) have been determined.Besides the well‐known mechanism of the HF formation in H2/F2 systems it appears clearly that in CH4/F2 flames the final concentration of fluorocarbon derivatives are close to those of fluorhydric acid. This evidence indicates that in rich methane‐fluorine flames the reaction CH3 + F2 → CH2F + HF and subsequent reactions of CH2F are important in addition of the primary attack of methane CH4 + F → CH3 + HF and CH4 + F → CH3F + H.