bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gelation in the reactions of dicarboxylic acid dichlorides with triols
Authors: Smith Robert S. , Stepto Robert F. T. 
Published: April 2003

AbstractGelation in reactions of triols with dicarboxylic acid dichlorides was studied at various dilutions. Adipoyl dichloride and sebacoyl dichloride were reacted with three triols of different molecular weights. The pairs of reactants were chosen so that the reaction systems were characterised by a range of values of v, the number of bonds in the smallest ring structure which could form. In all cases gelation occurred at extents of reaction in excess of those predicted by the Flory‐Stockmayer theory. The excess reaction increased with dilution, and decreased with increase in v.The results are interpreted in terms of a combination of Frisch's and Kilb's theories of gelation, in which λ, the intramolecular branching parameter of Frisch, is given by the equation λ = const. v−3/2{(OH)0+(COCl)0}−1.
13C‐kernresonanzspektren von ligninen, 5. Oligomere ligninmodellsubstanzen
Authors: Nimz Horst , Lüdemann Hans‐Dietrich 
Published: April 2003

AbstractDie 13C‐NMR‐Spektren von Ligninmodellsubstanzen mit einer “α‐O‐4”‐Bindung werden mitgeteilt. Die Änderung der chemischen Verschiebungen durch Acetylierung und Umsetzung mit Fluor‐2,4‐dinitrobenzol wird an Ligninmodellsubstanzen untersucht.
Über den einfluß von fängern auf die hochfeldpolymerisation von α‐methylstyrol
Authors: Wablat Wolfgang , Schmidt Werner Fritz , Schnabel Wolfram 
Published: April 2003

AbstractDie durch Feldemission (FE) in flüssigem α‐Methylstyrol ausgelöste Polymerisation wird durch Kationenfänger (N(C2H5)3, H2O, Cyclopropan) inhibiert. Die Elektronenfänger SF6, N2O, CO2 und O2 inhibieren ebenfalls, wobei die Inhibitorwirksamkeit in der genannten Reihenfolge abnimmt. Dieses Verhalten wird darauf zurückgeführt, daß von der Hochfeldelektrode emittierte Elektronen Monomermolekeln ionisieren; dabei gebildete Radikalkationen starten die kationische Polymerisation. Durch Kationenfänger wird daher die Wachstumsreaktion inhibiert, während Elektronenfänger die Startreaktion inhibieren.Bei der durch Feldionisation (FI) gestarteten Polymerisation sind Elektronenfänger wirkungslos; Kationenfänger inhibieren dagegen.Aufgrund der Abhängigkeit der spezifischen Polymerausbeute von der N(C2H5)3‐Konzentration wurde abgeschätzt, daß im Falle der FE nur 1 bis 10% der emittierten Elektronen polymerisationsauslösend wirken. Im Falle der FI starten bis zu 100% der an der Hochfeldelektrode erzeugten Ladungsträger kinetische Ketten.Bei allen Versuchen wurde Oligomeres (Polymerisationsgrad 3 bis 4) durch eine Kettenreaktion gebildet. Die spezifische Oligomerausbeute nahm bei der FE‐initiierten Polymerisation mit steigender SF6‐Konzentration bemerkenswert zu.
HR‐NMR study of formation and structure of the stereocomplex of poly(methyl methacrylate) in solution
Authors: Spěváček Jiří , Schneider Bohdan 
Published: April 2003

AbstractFrom high‐resolution NMR spectra of mixtures of solutions of isotactic and syndiotactic poly(methyl methacrylate), the content p of the associated stereocomplex was determined. From the values of p, the minimum length of associated syndiotactic sequences was found to be ca. 10 monomeric units in aromatic solvents and ca. 3 such units in CCl4 and CD3CN. In the associated stereocomplex the ratio of monomeric units in isotactic and syndiotactic sequences is (iso/syndio) = 1:1,5; the process of dissociation of the stereocomplex with increasing temperature is reminiscent of the melting of microcrystallites. The melting point of associated segments in a given solvent increases with the length of the associated sequences.
Sedimentation and light scattering study of block copolymer association
Authors: Tuzar Zdeněk , Petrus Vladimír , Kratochvíl Pavel 
Published: April 2003

AbstractDilute solutions of a three‐block styrene‐butadiene‐styrene copolymer in the mixed selective solvent tetrahydrofuran/allyl alcohol exhibit a more or less pronounced turbidity. Sedimentation analysis and light scattering reveal that these solutions contain two components, namely, a molecularly dissolved copolymer (unimer) and rather compact supermolecular aggregates (micelles) with a relatively narrow molecular weight distribution. The unimer/micelles weight ratio and the weight of micelles were determined as a function of the composition of the mixed solvent, temperature, and copolymer concentration.
Azo‐Initiatoren, 3.. Lösungsmitteleinfluß auf den thermischen zerfall von p‐methoxyphenylazo‐2‐methylpropandinitril
Authors: Kerber Robert , Nuyken Oskar , Steinhausen Rainer 
Published: April 2003

Abstractp‐Methoxyphenylazo‐2‐methylpropandinitril (1) zerfällt thermisch in allen angewendeten Lösungsmitteln nach 1. Ordnung, abhängig von der Viskosität und Polarität des Lösungsmittels, jedoch verschieden schnell. Unter der Annahme einer nichtsynchronen Spaltung der C—N‐Bindungen der Azogruppen lassen sich diese experimentellen Beobachtungen sowohl im Hinblick auf die Geschwindigkeitskonstanten als auch hinsichtlich des dabei nur unvollständig freigesetzten Stickstoffs widerspruchsfrei erklären.Die berechneten thermodynamischen Funktionen des Übergangszustandes zeigen, daß ΔG≠ nahezu unabhängig vom Lösungsmittel 115±4kJ/mol beträgt und deshalb für die Charakterisierung des thermischen Zerfalls der Azoverbindungen besonders geeignet erscheint.Zur Stützung des radikalischen Zerfallsmechanismus wurde die Azoverbindung 1 zur Initiierung der Polymerisation von Acrylnitril in Methanol und von Styrol in Toluol eingesetzt.
Cationic polymerization of cyclic amines, 3. Polymerization of azetidine
Authors: Schacht Etienne H. , Goethals Eric J. 
Published: April 2003

AbstractAzetidine (1) polymerizes under the influence of various cationic initiators. In methanol and with perchloric acid as initiator, the monomer 1 is first converted into a dimer (N‐(3‐aminopropyl)azetidine (3)) which then polymerizes further to polymer. When all monomer has disappeared, the reaction mixture consists for 70% of the dimer 3. The rate constant of dimer formation at 70°C is 1,50·10−3 dm3mol−1s−1. The formation of 3 is attributed to the higher basicity of 1 compared to 3, which causes a transfer of a proton from the protonated 3 to 1. The structure of the polymer was determined by 300 MHz 1H‐NMR spectroscopy. It contains 20% of tertiary, 60% of secondary and 20% of primary amino functions.
Polymers containing stable free radicals, 6. Reactions of 2,4,6‐triphenyl‐3,4‐dihydro‐s‐tetrazin‐1 (2H)‐yl (1,3,5‐triphenylverdazyl) with organometallic compounds
Authors: Miura Yozo , Morimoto Yuzo , Kinoshita Masayoshi 
Published: April 2003

Abstract2,4,6‐Triphenyl‐3,4‐dihydro‐s‐tetrazin‐1(2H)‐yl (1) (1,3,5‐triphenylverdazyl) was allowed to react with ethyl‐ and butyllithium, ethyl‐, isopropyl‐, and butylmagnesium bromide, as well as benzylmagnesium chloride to give the coupling products 2a–d. These results indicate that structures corresponding to 2 are present in the polymers resulting from vinyl monomers containing the verdazyl structure, if they are initiated with alkyllithium or a Grignard reagent. A reaction mechanism is discussed.
Modellsubstanzen für polymere Redoxsysteme, 8. Tetra‐ und hexavalente Redoxsysteme vom 1,4‐Benzochinon‐Typus
Authors: Storck Winfried , Manecke Georg 
Published: April 2003

AbstractEs werden die Synthese und die Eigenschaften von 2‐(1,4‐Benzochinon‐2‐ylmethyl)‐5‐methyl‐1,4‐Benzochinon (2b), der drei isomeren Bis(1,4‐Benzochinon‐2‐ylmethyl)benzole 8a, 9a und 10a und der drei hierzu homologen Bis[2‐(1,4‐Benzochinon‐2‐yl)äthyl]benzole 8b, 9b und 10b beschrieben. Sie stellen oligomere Redoxsysteme dar. Durch 1H‐NMR‐spektroskopischen Strukturbeweis von 2‐(2,5‐Dihydroxybenzyl)‐1,4‐Benzochinon (4) wird belegt, daß in saurer Lösung teiloxidierte tetravalente Redoxsysteme vom BenzochinonTypus ein miteinander verknüpftes Hydrochinon‐ und Chinonsystem darstellen. Die teilreduzierte, o‐verknüpfte Bis(chinonyl)‐Verbindung 8a bildet in Lösung leicht einen intramolekularen CT‐Komplex, was bei den anderen Verbindungen nicht beobachtet wird.Als spezielle Modelle für Oxidations‐Reduktions‐Polymere wurden ferner drei völlig symmetrische, hexavalente Redoxsysteme synthetisiert und charakterisiert: Tris(1,4‐Benzochinon‐2‐yl)‐methan (17), Tris(1,4‐Benzochinon‐2‐ylmethyl)benzol (19a) und Tris[2‐(1,4‐Benzochinon‐2‐yl)äthyl]benzol (19b).
Ion‐radical mechanism of the polymerization of 2,6‐dimethylphenol by oxidative coupling catalysed by CuCl2‐amine complex
Authors: Kresta Jiři , Tkáč Alexander , Přikryl Rudolf , Malik Ludovít 
Published: April 2003

AbstractThe preparation of poly[oxy‐(2,6‐dimethyl)‐1,4‐phenylene] (2) via polymerization of 2,6‐dimethylphenol (1) by oxidative coupling with CuCl2‐amine complexes is described. The reaction mechanism was studied by means of ESR, NMR spectroscopy, and conductivity measurements. It was established that the CC coupling products (dipheno‐quinones) are formed by recombination of phenoxyl radicals and that the very high selectivity of the CuCl2‐amine complex catalysts in the formation of 2 (CO coupling) is due to the cationic mechanism based on the consecutive reaction of the phenoxyl radicals with Cu(II) complexes. This consecutive reaction of the phenoxyl radicals with Cu(II) complexes is responsible for the non‐measurable level of polymeric radicals 5 by ESR, previously reported.
A new method for the synthesis of polymers containing amide and imide groups in the main chain
Authors: Iwakura Yoshio , Uno Keikichi , Chau Nguyen 
Published: April 2003

AbstractPoly(pyromellitdiimidoarylenecarbonyliminoaryleneiminocarbonylarylene)s [poly(amide‐imide)s] (7 and 12) were prepared from pyromellitic dianhydride (6) and dicarbamates (5) (diurethanes) containing amide linkages. The same polymers could also be prepared directly from aromatic isocyanatocarboxylic acid chlorides (10), diamines (11) and 6. In the latter method, the addition of an equimolar amount of water was required for the formation of the imide ring in the main chain of the polymer. Model reactions were carried out to determine the reaction conditions for the two methods. Reaction mechanisms are proposed.
Growth mechanism of crystals of glycine‐L‐alanine copolymer in the course of polymerization
Authors: Kim Kea Yong , Kōmoto Tadashi , Katakai Ryoichi , Ōya Masanao , Kawai Tōru 
Published: April 2003

AbstractIn order to examine the growth mechanism of copolymer crystals formed during polymerization, the heterogeneous copolymerization of glycine N‐carboxy anhydride (NCA) and L‐alanine NCA has been studied in acetonitrile. In the polymerization systems with higher contents of glycine, the crystal growth occurs through formation of the cross‐β type structure as proposed previously for poly(S‐methyl‐L‐cysteine), giving rise to chain‐folded crystals and rather high conversions. The high conversion is accounted for by the widening of the cross‐section of the β‐chains in the backbone crystal, due to the introduction of L‐alanine residues into the polyglycine chain. Copolymerization at higher contents of L‐alanine leads to conversions over 90% and extended chain crystals, due to the formation of α‐helices on the ribbon‐like crystals composed of the β‐structure just as in the case of L‐alanine NCA homopolymerization, indicating the occlusion of the glycine residues into the helices.
The curing reaction of an epoxide resin with 2‐ethyl‐4‐methylimidazole, a calorimetric study of the kinetics of formation of epoxide‐imidazole adducts
Authors: Barton John M. , Shepherd Peter M. 
Published: April 2003

AbstractThe kinetics of formation of the 1:1 and 2:1 adducts of (in terms of equivalents of epoxide) 2,3‐epoxypropyloxybenzene (2) and 2,2‐bis[p‐(2,3‐epoxypropyloxy)phenyl]‐propane (1) with 2‐ethyl‐4‐methylimidazole (3) have been investigated by differential scanning calorimetry (DSC). A comparison of isothermal and dynamic data for the 1:1 system 2/3 showed that the dynamic rate cannot simply be equated to the isothermal rate, but the true dynamic rate equation, dα/dt = (∂α/∂tT)+(∂α/∂Tt) (dT/dt), gave good agreement with the isothermal data. The dynamic DSC measurements indicate that all of the reactions approximate to first order kinetics and have similar values for activation energy (E = 81–93 kJ/mol) and pre‐exponential factor (log A ≈ 9–10). The results support the suggestion that adduct formation is likely to be the first stage of the resin curing reaction catalyzed by 3.
Mathematisches Modell der polyaddition von 1‐chlor‐2,3‐epoxypropan an ein diol
Authors: Novák Jiřiacute; , Šváb Vladimír 
Published: April 2003

AbstractIn dem mathematischen Modell, mit dem die Produktzusammensetzung bei der Polyaddition von 1‐Chlor‐2,3‐epoxypropan (1) (Epichlorhydrin) an ein Diol berechnet wurde, wurde die Voraussetzung gemacht, daß die Reaktivitäten der 3‐Chlor‐2‐hydroxypropyloxy‐Endgruppen gleich (d. h. von der Molekülgröße unabhängig) sind und daß sich der Epoxidring von 1 nur unter Bildung der Cα‐Äther öffnet. Ein Vergleich des für verschiedene kinetische Parameter berechneten und des experimentell im Augenblick des völligen Durchreagierens von 1 bestimmten Anteiles von nicht abreagiertem 1,2‐Propandiol (bei verschiedenen Ausgangsmolverhältnissen 1/Diol) erlaubte die Bestimmung der Verhältnisse der Geschwindigkeitskonstanten von fünf möglichen Reaktionen des untersuchten Systems. Für die Polyaddition von 1 an 1,2‐Propandiol wurde die beste Annäherung bei den relativen Geschwindigkeitswerten K1 = 0,8; K2 = 0,6 und K3 = K4 = 0,5 erzielt.
Molecular dimensions of polymers dissolved in binary mixtures of polar and non‐polar solvents, 2. Poly(methyl methacrylate)
Authors: Dondos Anastasios , Havredaki Vassiliki , Mitsou Artemis 
Published: April 2003

AbstractViscometric measurements are performed for poly(methyl methacrylate) fractions dissolved in the following solvent mixtures: benzene/chloroform, benzene/tetrahydrofuran, benzene/ethyl acetate, and dioxane/chloroform. The polymer exhibits a conformational transition which occurs in a narrow region of solvent composition. This transition is expressed by a discontinuity of the intrinsic viscosity, Huggins' constant, and the unperturbed dimensions.At the transition point all solvent mixtures present approximatively the same dielectric constant.
Polymerisationen und polymerisationsinitiatoren, 16. Einfluß von Thioxo‐Gruppen in barbitursäurederivaten auf die polymerisationsauslösung von methacrylsäure‐methylester
Authors: Bredereck Von Hellmut , Menzel Peter , Argosino Rosalinda , Bihlmaier Werner 
Published: April 2003

Abstract5‐Alkyl‐1,3‐dimethylbarbitursäuren lösen in Gegenwart von Cu2+, Cl− und Luftsauerstoff die radikalische Polymerisation von Methacrylsäuremethylester aus. Die Initiatorwirkung wi+d durch Thioxo‐Gruppen in 2‐Stellung etwas verstärkt, in 4‐ bzw. 4,6‐Stellung dagegen stark vermindert. Die Wirkung dieser 4‐ bzw. 4,6‐Thioxobarbitursäuren als Inhibitoren beruht auf der Stabilisierung der primär gebildeten Radikale durch die benachbarten Thioxo‐Gruppen, wodurch Weiterreaktion am S‐Atom unter Dimerisierung zu Disulfiden erfolgt. Bei der Cu(II)‐katalysierten Polymerisationsauslösung wird die Inhibierung durch die Bildung schwerlöslicher Kupfer(I)thioxobarbiturate noch verstärkt.
Thermal properties of isotactic polypropylene quenched from the melt and annealed
Authors: Fichera Annamaria , Zannetti Roberto 
Published: April 2003

AbstractDSC investigations on isotactic polypropylene (it‐PP) quenched from the melt and annealed over a range of temperatures are reported. The results confirm the existence of saturation levels of the ordered phase for different annealing temperatures, previously revealed by X‐ray diffraction methods.Thermal, X‐ray diffraction, and density data are correlated in terms of the extent of the ordered phase present in the it‐PP.
Relative reactivity of cis‐ and trans‐1,3‐pentadiene in the cationic copolymerization with isobutene
Authors: Priola Aldo , Cesca Sebastiano , Ferraris Giuseppe , Bruzzone Mario 
Published: April 2003

Abstractcis‐1,3‐Pentadiene (2) and trans‐1,3‐pentadiene (3) were copolymerized with isobutene (1) in the presence of (C2H5)2AlCl+(CH3)3CCl or (C2H5)2AlCl+Cl2 in the range of temperatures between —35 and —70°C. The reactivity ratios, determined at —55°C, are:r1.2=5,0 and r1.3=2,3, while the chain transfer coefficients are Kt.2=50 and Kt.3=113. The activation energies are: EMv.2= —13,8kJ/mol (—3,3 kcal/mol) and EMv.3= —16,7kJ/mol(—4,0 kcal/mol). Spectroscopic analyses (IR, 1H‐NMR) showed that in both copolymers the 1,4‐trans structure is prevalent over the 1,2‐trans‐enchainment. The fact that 3 is more reactive than 2 can be correlated with a greater electron‐density (13C‐NMR data) on C‐1 in compound 3.
Polymorphosis of poly(oxymethylene) crystals grown in a cationic polymerization system of 1,3,5‐trioxane in solution
Authors: Iguchi Masatoshi , Murase Ichiki 
Published: April 2003

AbstractThe morphology of poly(oxymethylene) appearing in the polymerization system of 1,3,5‐trioxane in cyclohexane using BF3 [or BF3O(C2H5)2] and water catalysis was studied in parallel with the kinetic behaviour of the reaction. Feather‐shaped crystals, whose poor reproducibility was a problem, were found to be formed in a limited range of catalytic conditions. As a function of the mole ratio H2O/BF3, the change of morphology was ordered as follows: needle‐like crystals (H2O/BF3<0,05), heterogeneous products (H2O/BF3=0,05 to 3), feather‐shaped crystals (H2O/BF3=3 to 10). and amorphous products (H2O/BF3>10). A new type of single‐crystal, tapered hexagonal rod, was found in the same catalytic region where feathershaped crystals were formed. The results of older preliminary work in a polar solvent, where a hexagonal, plate‐like crystal had been obtained, are also briefly reconsidered in the discussion.
Dilute solution properties of critically branched systems
Authors: Gordon M. , Kajiwara K. , Peniche‐Covas C. A. L. , Ross‐Murphy S. B. 
Published: April 2003

AbstractLight‐scattering measurements were carried out on critically branched polycondensates of 1,3,5‐benzenetriacetic acid and 1,10‐decanediol, and the results were analysed according to the theory of cascade processes, developed especially for this system, viz. the pathweighting generating function method. It is postulated that the amount of chain expansion found in these branched copolycondensate samples was due to short‐range rather than long‐range interactions. The long‐range interactions seem to vanish in the critically branched state. The rotational isomeric state model was used to calculate the comparative unperturbed dimensions for the linear homologue of the above polycondensate, i.e. poly(1,3‐benzenediacetic acid/1,10‐decanediol).
On the source of X‐ray small angle scattering in rubbers vulcanized with methacrylic acid salts
Authors: Anfimov Boris , Dontsov Anatoli , Ferracini Elena , Ferrero Adele , Hosemann Rolf , Riva Fernando 
Published: April 2003

AbstractStyrene‐butadiene rubber (SBR) is mixed with zinc methacrylate (ZnM) powder SBR: ZnM = 5:1 by weight. Wide angle X‐ray diffraction proves that the ZnM crystallites are larger than 240Å. The pure SBR and the SBR‐ZnM mixture exhibit the same small angle X‐ray pattern, indicating particle sizes for SBR and ZnM beyond the resolving power. After annealing the SBR‐ZnM mixture for 30min at 155°C a weak small angle X‐ray scattering (SAXS) pattern appears which indicates particles of 160Å diameter with a polydispersity of gy = 0,2. The same particle size is found from wide angle X‐ray scattering (WAXS) which proves that these particles are ZnM microcrystals and split from the larger crystals. Heating the mixture SBR‐ZnM (100 parts by weight) with 0,8 parts by weight dicumylperoxide, (bis(1‐methyl‐1‐phenylethyl)peroxide) for 30min at 155°C gives rise to a seven times stronger WAXS pattern with the same particle dimension 160Å and polydispersity gy = 0,2. The particle scattering is superimposed by a paracrystalline interference which indicates that the ZnM particles have a mean distance of 250Å and hence are homogeneously spread over the SBR matrix. The ZnM particles have lost their innercrystalline structure, since the WAXS reflection has become very diffuse. Striking similarities to the graft copolymerization of styrene on polyethylene are discussed.
Synthèse par voie radicalaire de polymères à extrémités hydroxylées, 2 Synthèse de polybutadiènes
Authors: Pinazzi Christian , Legeay Gilbert , Brosse Jean‐Claude 
Published: April 2003

AbstractLa polymérisation du butadiène amorcée par l'eau oxygénée en milieu alcoolique, conduit à la formation d'oligomères de faibles masses moléculaires (voisines de 500) et de polymères hydroxytéléchéliques dont la masse moléculaire est comprise entre 1500 et 11000. Les produits formés présentent essentiellement une structure 1,4 (trans). Les polymères possèdent entre deux et trois hydroxyles par macromolécule, ce chiffre pouvant atteindre six dans certains cas. Les études systématiques ont été rélisées en faisant varier les proportions d'alcool, d'eau oxygénée et du monomère constituant le mélange réactionnel.
Effect of structure on glass transition temperatures of poly(methacrylic ester)s with bulky side groups
Authors: Gargallo Ligia , Russo Mauricio 
Published: April 2003

AbstractThe values of the vitreous transition temperature, Tg, of three poly(methacrylic ester)s having bulky side groups are correlated with structural effects. Tg has been obtained experimentally by means of differential calorimetry and by the tensiometric method suggested by Ferroni. The experimental values of Tg agree well with the calculated ones obtained by the method of Van Krevelen. The values of Tg determined by differential calorimetry are markedly affected by the heating rate and by the molecular weight of the fractions.The solubility parameters of the polymers studied have been estimated. Poly(p‐tert‐butylphenyl methacrylate), (BPh), exhibits higher values for the solubility parameter, the steric hindrance parameter σ and the glass transition temperature Tg than poly(p‐tert‐butylcyclohexyl methacrylate), (BCy), and poly(neopentyl methacrylate), (NPe).These results have been interpreted in terms of intermolecular forces and steric hindrance effects, which would be greater in BPh than in BCy and NPe.
Kinetik der Bromierung von Phenolen und phenolischen Mehrkernverbindungen, 1. Mechanismus und meßmethode
Authors: Böhmer Volker , Niemann Wilhelm 
Published: April 2003

AbstractDie Bromierung von 2‐(2‐Hydroxy‐5‐methylbenzyl)‐4,6‐dimethylphenol (1) und 2‐[2‐Hydroxy‐3‐(2‐hydroxy‐5‐methylbenzyl)‐5‐methylbenzyl]‐4,6‐dimethylphenol (2a) wurde in Eisessig bei 22°C untersucht. Die Reaktion läßt sich für [Br2]0 = 1,4·10−3 bis 6,0·10−3 mol dm + und Konzentrationen der phenolischen Verbindungen [P]0 zwischen 1,1·10−3 und 5,5·10−3mol dm−3 durch das folgende Geschwindigkeitsgesetz beschreiben:

Während die gebildete Bromverbindung keinen Einfluß auf die Reaktionsgeschwindigkeit hat, verlangsamt der entstehende Bromwasserstoff die Reaktion. Die Bromierung ist trotzdem zur Bestimmung der Reaktionsfähigkeit von Phenolen und phenolischen Mehrkernverbindungen gut geeignet, da die Reaktion leicht durch Messung der Absorption des Broms bei 450 nm verfolgt werden kann. Zur Auswertung wurde dabei für kleine Umsätze (15%) ein Geschwindigkeitsgesetz 2. Ordnung zugrunde gelegt und die formale Geschwindigkeitskonstante k′2 als Funktion der Bromkonzentration bestimmt.