Modification of poly(vinyl alcohol) through reaction with phosphorus-containing reactants

Crosslinked products of the form: and have been formed from the interfacial condensation of phosphorus diacid halides with poly(vinyl alcohol). Product yield and amounts of phosphorus reactant included in the product increases as the amount of base increases. Product stability in aqueous systems decreases in the order neutral > base > acid.     

Structure of the tetramer of α-methylstyrene

The structure of the tetrameric dianion formed by α-methylstyrene in tetrahydrofuran by reaction with sodium has been examined. Mass spectral, NMR, infrared, and kinetic data all indicate that the structure is rather than the structure which had previously been assumed for this species.     

Oxazolidines versus schiff bases

The formation of oxazolidines from propionaldehyde and aliphatic β-aminoalcohols is complicated by the appearance of appreciable amounts of unsaturated Schiff bases. The simple Schiff base, often the dominant species when aromatic aldehydes react with amines, could not be detected in the present aliphatic systems. We conclude that in aliphatic systems the order of stability is and . The gem-dimethyl group α to nitrogen stablizes the heterocyclic ring remarkably.     

Synthesis and psychotropic properties of furyl- and thienyl-germatranes

Trihalogermyl-furans and -thiophenes were prepared by inserting germanium dibromide (GeBr₂) generated from the dibromogermane(II) dioxanate complex into the carbon-halogen bond of halo-furans and -thiophenes. Their ethanolysis and transesterification by triethanolamine yielded the germatranes which were subjected to psychotropic activity assays. The psychotropic properties of germatranes were found to depend on the type of the heterocycle and on the position of the germatrane moiety.     

Darstellung und Eigenschaften von Ti-substituierten N-Heterocyclen

Preparation and Properties of Ti-substituted N-Heterocycles The compounds (x = 2 to 6) have been prepared by transamination of Ti(NMe₂)₄ with the heterocyclic amines and have been characterised by elemental analyses and ¹H NMR and IR spectroscopy. The dependence on both x and n of the thermal decomposition has been studied for the series and . The results can be interpreted in terms of the steric strain of the R₂N and substituents. Apart from the piperidido groups none of the ligands exhibit protective group properties comparable to the R₂N groups.     

Durch Nachbargruppenbeteiligung induzierte (1,2)-Chlorwasserstoff-Eliminierung aus ionisiertem 2-(β-Chloräthyl)- benzoesäuremethylester

By using deuterium labelled compounds and collisional activation spectra the mechanism of the unusually intensive HCl elimination from 2-(β-chloroalkyl)benzoic acid methyl ester as well as the structure of the product ion have been elucidated. It can be shown that the structure of the stable ion (lifetime τ～10?5 s) is best represented by 2-vinyl benzoic acid methyl ester whereas the reactive ion (lifetime τ<10^?6 s) at least partially rearranges to a cyclic ion. The hydrogen chloride elimination from 2-(β-chloroalkyl)benzoic acid is apparently a simple 1,2 process. A closer examination reveals that the reaction represents a further example of an unusual neighbouring group participation of the ester function.     

The loss of CH3⋅ from some unsaturated dithioesters

The mechanism for the loss of CH₃? (and C₂H₅?) from the molecular ions of some unsaturated dithioesters of the type with n=0, 1, 2, has been studied. Based on first field free region metastable ion characteristics it is proposed that 1,3-dithiolium type product ions are generated. Deuterium labelling experiments indicated that the molecular ions of the 2-alkenyl alkanedithioates undergo a rearrangement prior to fragmentation which resembles the [3,3]sigmatropic rearrangement in solution chemistry.     

Interfaces between coexisting phases in polymer mixtures: What can we learn from Monte Carlo simulations?

Symmetric binary polymer mixtures are studied by Monte Carlo simulation of the bond fluctuation model, considering both interfaces between coexisting bulk phases and interfaces confined in thin films. It is found that the critical behavior of interfacial tension and width is compatible with that of the Ising model, as expected from the universality principle. In the strong segregation limit, only qualitative but not quantitative agreement with the self-consistent field (SCF) theory is found. It is argued that the SCF theory requires but for the short chains studied (N = 32 effective monomer units per chain), the limit is only reached for close to unity. Also, the effective χ-parameter decreases in the interface. It is shown that the interfacial width w does not increase by the adsorption of block copolymers as long as their areal density is still dilute (“mushroom” regime). But a broadening of interfaces does occur for thin films confined between walls at distance D, due to fluctuations that lead to for short-range forces, in agreement with experiment.     

Le Spectre de L'Alcool Propargylique en Fonction du pH. Un Exemple de Transferts Protoniques Complexes sur un Diacide Organique

Dimethyl sulphoxide (DMSO) is used as a solvent to investigate the kinetic acidity of very weak organic diacids by ¹H d.n.m.r. An inspection of the spectrum of propargyl alcohol as a function of the pH allows the assignment of various proton transfer mechanisms:      

Synthese „anorganischer”︁ Tintenfisch-Moleküle

Inorganic Pode-Type Molecules The reaction of monosubstituated polyethylenglykoles [m = 0—4, R = Cl, OCH₃, OAs(CH₃)₂, OSi(CH₃)₃] with amino compounds (CH₃)_xE[N(CH₃)₂]_y(E = Si, x = y = 2; E = Si, x = 1, y = 3; E = P, x = 0, y = 3; E = As, y = 0, y = 3) results in the formation of pode-type molecules of the formula . The synthesis and rearrangement of these compounds by heating is described.     

Massenspektrometrische Untersuchung organischer Stickstoffverbindungen. XXVII—Intramolekulare Redoxreaktionn bei ionisierten ortho-substituierten Nitroaromaten

Collisional activation demonstrates that the stable ions from o-nitrobenzaldehydedimethylacetale possess the structure of ionized o-nitroso benzoic acid methyl ester. Contrary to previous conclusions it is demonstrated that the structure of the stable ions (m/e 135) from different precursors [i.e. o-nitrobenzyl alcohol o-nitrobenzyl cyanide and o-nitrobenzaldoxime is best represented by 2,1-benzisoxazoline-3-one. Ionized o-nitrosobenzaldehtde rearranged to 2,1-benzisoxazoline-3-one prior to collision induced decomposition, whereas 2-benzoxazolinone and 3-hydroxy-1,2-benzisoxazole do not rearrange within 10^?5 s.     

Zur Darstellung von Cyclophosphaten,Cyclophosphatophosphonaten, Diphosphonaten und Diphosphiten in Harnstoffschmelzen

Preparation of Cyclophosphates, Cyclophosphatophosphonates, Diphosphonates, and Di-phosphites in Urea Melts Ammonium cyclotriphosphate (NH₄)P₃O₉, ammonium cyclotetraphosphate [P^IV? P^IV ? O? ]₂, ammonium cyclotriphosphatophosphonates Ammonium organyldiphosphonates And ammonium diphosphites are prepared in high yields on heating acidic phosphates, phosphonates, and phosphites in urea or urea/ammonium nitrate melts. The mechanism of the dehydration of phosphorus compounds containing POH groups in molten urea is discussed.     

Anionic copolymerizations of acrylonitrile with β-propiolactone

Anionic copolymerizations of acrylonitrile (monomer 1) with β-propiolactone (monomer 2) and the structures of the resulting copolymers were studied. The copolymerization with sodium cyanide in N,N-dimethylformamide gave copolymers of the structure I containing acid anhydride linkage in the molecular chains, with the monomer reactivity ratios, r₁ = 1.20, r₂ = 0.00. The copolymerization with potassium hydroxide gave either copolymers of the structure II (r₁ = 0.00, r₂ = 3.64 at 30°C; r₁ = 0.00, r₂ = 5.00 at 40°C) in N,N-dimethylformamide or only β-propiolactone homopolymer in toluene.      

Chlorine Dioxide as an Electron-Transfer Oxidant of Olefins. Preliminary Communication

The kinetics and product studies of oxidation of eight olefins 1 - 8 by ClO₂ in H₂O in the pH range 3-7 are described. The reaction is faster as the pH decreases. At pH < 4, ClO₂ reacts equimolarly with olefins to yield isomeric mixtures of chlorohydrines and 1,2-dioxygenated products, following the equation: The order of reactivity is: (E)-stilbene > indene > β-methylstyrene > acenaphthylene > α-methylstyrene > styrene > cyclohexene > allylbenzene. A multi-stage radical-cation mechanism is proposed, in which an initial reversible protonation: is followed by an electron-transfer stage (rate-determining): The cation-radical thus produced, adds rapidly an additional ClO₂ to form dioxygenated products. The chlorohydrines most likely arise from HClO additions to the olefinic double bonds, which, in turn, generate from dismutation of 2 HClO₂ into HClO + H⁺ + ClO.     

Fluorsulfonylstickstoffverbindungen

The reactions of fluorosulfonylurea derivatives with phosphorus pentachloride in carbon tetrachloride leads to and . These compounds are easily fluroinated by arsenic trifluoride to the corresponding fluorosulfonyl derivatives. It was shown that PCl₅ is reliable for the fluorine-chlorine exchange. Isocyanate esterchlorides as well as carbonyl-fluoride derivatives react with compounds which have an active hydrogen atom. By this way were prepared: . By hydrolysis of , is probably formed as the first reaction product. The acid could be trapped with tetraphenylphosphoniumchloride as a well-cristalline salt. Fluorosulfonyl isocyanate reacts with aldehydes to the following compounds: FSO₂N ? CHCH₃, FSO₂N ? CHC₂H₅, FSO₂N ? CH? CH(CH₃)₂ and FSO₂N ? CHC₆H₅. The physical and chemical properties as well as IR and NMR spectra of the compounds are described and, in part, compared and discussed.     

4-Thiazoline-2-thiones. V. Kinetic vs. thermodynamic control of the conjugate addition at the S- vs. N-positions to acrylonitrile and methyl acrylate

The basic catalyzed conjugate addition of the title system in methanol was found to occur at either the S- or N-atoms, or concurrently at the S- and N-atoms, of the moiety of the heterocycle. Evidence indicates that the formation of the two types of adducts depends on an equilibrium between the reactions of conjugate addition and reversal. Certain choice of isolation of the two types of products is allowed by control of the reaction conditions.     

Kinetics of the First Order Autocatalytic Decomposition Reaction of Nitrocellulose （13.86% N）

The kinetics of the first order autocatalytic decomposition reaction of nitrocellulose (NC, 13.86% N) was studied by using DSC. The results show that the DSC curve for the initial 50% of conversion degree of NC can be de scribed by the first order autocatalytic equation dy/dt =-10^16.3 exp (-181860/RT)y-10^16.7ex(-173050/RT)y(1-y) and that for the latter 50% conversion degree of NC described by the reaction equations dy/dt=-10^16.4exp(-154820/RT)y (n=1) and dy/dt=-10^16.9 exp(-155270/RT) y^2.80(n≠1).     

Cyclization by the intermediates of phenylthio- and phenoxy carbamoyl. Formation of azasuccinic anhydrides and their polycondensation products. Intervention of the carbamoyl pyridinium cation

The N-(p-nitrophenoxy-carbonyl) derivatives of glycine, DL -alanine and DL -leucine are transformed by the action of pyridine into azasuccinic, 3-methyl-2-azasuccinic and 3-isobutyl-2-azasuccinic anhydride, respectively. These cyclisations occur probably via the intermediate N-carbamoyl-pyridinium cation , the rate of cyclisation seems to depend on the concentration of the intermediate in the form of the dipolar ion , i.e. the ionised carboxyl is necessary for the reaction. In γ-collidine the cyclisation occurs very slowly; this is attributed to the slowness due to steric hindrance of the production of N-carbamoyl-γ-collidinium cation and its instability. The azasuccinic anhydrides mentioned polycondense, yielding the corresponding polyglycine, poly-DL -alanine and poly-DL -leucine. This reaction too is catalysed by pyridine; it can also be effected by γ-collidine, but the efficacity of the latter in comparison with pyridine is even less than in the catalysis of the cyclisation described above. N-(p-nitrophenoxy-carbonyl)-glycine reacts with lysozyme in the presence of pyridine; several glycine residues are introduced into the enzyme molecule, the product being insoluble and poorly active.     

Effect of gegen ion in cationic polymerization and copolymerization of trioxane

p-Chlorophenyldiazonium hexafluorophosphate has been reported to be a superior catalyst for cationic polymerization and copolymerization of trioxane as compared to boron trifluoride dibutyl etherate (BF₃·Bu₂O)¹. In the present investigation the effect of anions derived from elements in Group VA, AsF and SbF, has been ascertained. It has been concluded that p-chlorophenyldiazonium hexafluoroarsenate is also a superior catalyst to boron trifluoride dibutyletherate (BF₃·Bu₂O), while p-chlorophenyl-diazonium hexafluoroantimonate is inferior. Copolymers with the highest polymer yield (>95%) and molecular weight (intrinsic viscosity = 4 to 5) were obtained with Simple dependences on catalyst concentration have been observed to hold for a wide catalyst concentration range ([M]/[C]) = (1 to 20) × 10⁵: For the same relationships hold. However, the polymer yield (75%) and molecular weights (intrinsic viscosity ?1) are considerably lower while the extent of chain transfer is higher. Furthermore, the polymerization proceeds with explosive violence. The quantitative aspects resulting from polymerization, for the most part, can be interpreted in terms of the extent of dissociation of the propagating ions.     

Darstellung neuer Spiro-Alkoxy-cyclophosphazatriene

Preparation of New Spiro-Alkoxy-Cyclophosphazatrienes New spiro-Alkoxy-cyclophosphazatrienes of the general formula are described. The preparation of the substances and their mass spectroscopic data are reported.