Polymerization of cyclic esters of phosphoric acid. VI. Poly(alkyl ethylene phosphates). Polymerization of 2-alkoxy-2-oxo-1,3,2-dioxaphospholans and structure of polymers

Five-membered cyclic esters of phosphoric acid of the general formula: ? CH₂CH(R)OP(O)-(OR′)O? polymerize readily to solid, soluble polymers of high molecular weight without any rearrangement known for various tri- and pentavalent organophosphorus monomers. ¹H-, ¹³C-, and ³¹P-NMR spectra of polymers confirmed their linear structure: where R is H, with R′ = CH₃, C₂H₅, n-C₃H₇, i-C₃H₇; n-C₄H₉, CCl₃CH₂, or C₆H₅, or R is CH₂Cl and R′ is C₂H₅. The use of n-C₄H₉Li, (C₅H₅)₂Mg, or (i-C₄H₉)₃Al as initiators leads to polymers with M _n = 10⁴–10⁵.     

Modification of PVC. XXVI. Syntheses and photocrosslinking of polysulfide pendant poly(vinyl chloride)

Poly(vinyl chloride) pendant with polysulfide (PS–PVC) having various degrees of substitution, various S substituents, and various numbers of atoms in the sulfur chain has been synthesized by the reaction of poly(vinyl chloride) with a thiol, sulfur, and triethylamine in dimethylformamide at 30°C for 0.4–5 hr. The photocrosslinking reaction has been investigated under ultraviolet irradiation at 250–450 mμ. The photocrosslinking reaction of PS–PVC is influenced by the degree of substitution, the nature of the S substituent, and the number of atoms in the sulfur chain. The degree of photocrosslinking r increased in the order, n-C₄H₉? < n-C₈H₁₇? < C₆H₅CH₂? < i-C₃H₇? < t-C₄H₉? . On the photocrosslinking of PS–PVC having two different S substituents, r increases in the similar order for aliphatic substituents and in the order NO₂C₆H₄? < ClC₆H₄? < C₆H₅CH₂? < CH₃C₆H₄? < t-C₄H₉C₆H₄? < C₆H₅? for the aromatic substituents. Further, r increases markedly with the increase of sulfur chain number for all PS–PVC. The chemical structure of the crosslinks and the crosslinking mechanism are discussed on the basis of the results.     

Study on ketalization reaction of poly(vinyl alcohol) by ketones. VIII. kinetic study on acetalization and ketalization reactions of poly(vinyl alcohol)

The kninetics of acid-catalyzed acetalization and ketalization of poly(vinyl alcohol) (PVA) were systematically studied in completely homogeneous media with carefully selected solvents. Thus the acetalization reaction was run in water with six aldehydes [R₁CHO (R₁ = H, CH₃, C₂H₅, n-C₃H₇, i-C₃H₇, ClCH₂)], whereas the ketalization in dimethylslfoxide with 11 ketones [R₂CH₃CO (R₂ = CH₃, C₂H₅, n-C₃H₇, i-C₃H₇, n-C₄H₉, i-C₄H₉, tert-C₄H₉, C₆H₅CH₂, C₆H₅CH₂CH₂), cyclopentanone, and cyclohexanone]. The latter was difficult to proceed in aqueous media. Both reactions were reversible and bimolecular and, despite the use of different solvents, gave similar heats of reaction (7.5 kcal/mol) and activation energies (ca. 15 kcal/mol) except for the case of formaldehyde and chloroacetaldehyde; however the equilibrium constants at 25°C showed that the acetalization is thermodynamically much more favored than the ketalization (ca. 5000 vs. 0.01–0.9), probably because of steric hindrance of the ketone substrate. The rate constants of hydrolysis (reverse reactions) for the poly(vinyl acetal) and poly(vinyl ketal) followed the Hammett-Taft equation to give a single p* (=3.60) that is very close to that for the hydrolysis of diethyl acetal and ketal. From these and other data, it was concluded that the polymer hydrolysis, as well as PVA acetalization and ketalization, are all electrophilic reaction where the formation of hemiacetal or hemiketal is the rate-determining step. © 1996 John Wiley & Sons, Inc.     

Rotational and vibrational distributions of N2(C 3Πu) excited by state-selected Ar(3P2) and Ar(3P0) metastable atoms

The ESR method is used to study the oxidation kinetics of the CH₃, C₂H₅, n-C₄H₉, i-C₄H₉, s-C₄H₉, t-C₄H₉, n-C₆H₁₃, C₆H₁₁, C₆H₅CH₂, CH₃C₆H₄CH₂, and C₆H₅CH₂CH₂ radicals in methanol matrix at 87 K. The reaction kinetics are shown to be describable in terms of a time-dependent rate constant k(t). The contribution from the matrix relaxation to k(t) has been determined. The oxidation rate and the shape of the kinetic curve are independent of the type of the radical. Models interpreting the experimental data are discussed.     

Massenspektrometrische Untersuchungen an Organophosphorverbindungen. II—Elektronenstoßinduzierte Fragmentierungen von Tetraorganodiphosphandisulfiden

The behaviour under electron impact (70 eV) which includes some rearrangement processes of some tetraorganodiphosphanedisulfides R₂P(S)-P(S)R₂ (R ? CH₃, C₂H₅, n-C₃H₇, n-C₄H₉, C₃H₅, C₆H₅) and CH₃RP(S)–P(S)CH₃R (R ? C₂H₅, n-C₃H₇, n-C₄H₉, C₆H₅, C₆H₅, C₆H₅,CH₂) is reported and discussed. Fragmentation patterns which are consistent with direct analysis of daughter ions and defocusing metastable spectra are given. The atomic composition of many of the fragment ions was determined by precise mass measurements. In contrast to compounds R₃P(S) loss of sulphur is not a common process here. The first step in the fragmentation of these compounds is cleavage of one P–C bond and loss of a substituent R?. The second step is elimination of RPS leading to [R₂PS]⁺ from which the base peaks in nearly all the spectra arise. The phenyl substituted compounds give spectra with very abundant [(C₆H₅)₃P]^+. and [(C₆H₅)₂CH₃P]^+. ions respectively, resulting from [M]^+. by migration of C₆H₅. Rearrangement of [M]^+. to a 4-membered P-S ring system prior to fragmentation is suggested.     

Evaluated and estimated kinetic data for phase reactions of the hydroperoxyl radical

Methods are discussed for the production and detection of the hydroperoxyl radical for use in gas phase kinetic studies. Rate constants for gas phase reactions of the hydroperoxyl radical with itself, H₂, H₂O, CO, NO, SO₂, O₃, C₂H₆, C₃H₈, i-and n-C₄H₁₀, C₂H₄, i-C₄H₈, HCHO, C₂H₅CHO, n-C₃H₇CHO, Br, O, OH, and H are critically evaluated. Recommended or estimated rate constant expressions with associated error limits are given applicable over specified temperature ranges (normally 300–1000°K). The reactivity of HO₂ compared with OH, O, H, F, Cl, Br, CH₃, and CH₃O is presented in tabular form and the implications for atmospheric chemistry are discussed.     

Polyterephthalates of 2,3-disubstituted butanediols-1,4: Effect of aliphatic substituents on Tg and Tm of the polyesters

Poly(2,3-dialkylbutanediol-1,4 terephthalates) with the alkyl substituents CH₃, C₂H₅, n-C₃H₇, iso-C₃H₇, n-C₄H₉, and n-C₁₀H₂₁, andn-C₁₆H₃₃ were synthesized from the corresponding 2,3-dialkylbutanediols-1,4 and dimethyl terephthalate or terephthaloyl chloride. The substituents of the butanediol-1,4 portion of the polyterephthalates influence the ¹³C NMR chemical shifts of the carbon atoms near the branching site, the glass transition (T_g), and the crystallizability. Small alkyl substituents do not change the T_g of the polymers, whereas bulky substituents such as the isopropyl group increase the T_g and long normal alkyl groups as substituents decrease the T_g of the polymers. Crystallinity in these polyterephthalates was found only with CH₃ and C₁₆H₃₃ as the 2,3-dialkyl substituents in the butanediol-1,4 portion of the polyester. This crystallinity of polyterephthalate of 2,3-di-C₁₆H₃₃ substituted butanediol-1,4 could be assigned to side-chain crystallization of the paraffinic groups.     

Reactions of nucleophilic addition of primary amines to the nitrilium derivative of the <Emphasis Type="Italic">closo</Emphasis>-decaborate anion [2-B<Subscript>10</Subscript>H<Subscript>9</Subscript>(N≡CCH<Subscript>3</Subscript>)]<Superscript>−</Superscript>

Compounds (Bu₄N)[2-B₁₀H₉{NH=C(NHR)CH₃}]⁻ are obtained by reactions of the tetrabutylammonium salt of the [2-B₁₀H₉(N≡CCH₃)]⁻ anion with aliphatic and aromatic primary amines RNH₂ (R = n-C₃H₇, n-C₄H₉, cyclo-C₅H₉, C₆H₅, cyclo-C₆H₁₁, n-C₆H₁₃, C₇H₇, C₈H₈NH₂, C₆H₄NO₂, and C₁₈H₃₇) and identified by IR, ESI/MS, and NMR (¹H, ¹¹B, and ¹³C) spectroscopy. The structures of the amidine-type derivatives [2-B₁₀H₉{Z-NH=C(NH-cyclo-C₅H₉)CH₃}]⁻ and [2-B₁₀H₉{Z-NH=C(NH-C₇H₇)CH₃}]⁻ are determined by X-ray diffraction.     

Quantum-Chemical Study of Electronic and Steric Structure of Vinyltetrazoles: I. 2-Substituted 5-Vinyltetrazoles

The total Mulliken charges on the carbon atoms of the vinyl group, populations of S-trans-(N¹)conformers, and internal rotation energies were calculated ab initio (HF/6-31G**, MP2/6-31G**, and MP2/6-31G**//AM1) for a series of 2R-5-vinyltetrazoles (R = CH₃, C₂H₅, i-C₃H₇, t-C₄H₉, C₆H₅). The calculation results were compared to the available experimental data.     

Kinetic Analysis of the Thermal Decomposition of Dialkyldithiocarbamates Chelates of Indium(III)

The kinetics of thermal decomposition of solid In(S₂CNR₂)₃ complexes, (R=CH₃, C₂H₅, n-C₃H₇,i-C₃H₇, n-C₄H₉ and i-C₄H₉), has been studied using isothermal and non-isothermal thermogravimetry. Superimposed TG/DTG/DSC curves show that thermal decomposition reactions occur in the liquid phase, except for the In(S₂CNMe₂)₃ and In(S₂CNPrⁱ ₂)₃ compounds. This revised version was published online in July 2006 with corrections to the Cover Date.     

ÜBER STERISCH SPERRIGE ORGANOPHOSPHORVERBINDUNGEN: ISOPROPYL-SUBSTITUIERTE THIOPHOSPHORYLBROMIDE

Abstract

Durch selektive Grignardierungsreaktionen werden Verbindungen des Typs R(i-C₃H₇)PBr erhalten und in R(i-C₃H₇)P(S)Br überführt. Die chemische Verschiebung δ p in RR'P(S)Br (R,R' = CH₃, C₂H₅, i-C₃H₇, t-C₄H₉) wächst linear mit der Zahl der ß-ständigen Methylgruppen in R und R'. AB₃C₃X-Spektren der i-C₃H₇P-Struktur-elemente werden berechnet.

Selective Grignard-type reactions lead to R(i-C₃H₇)PBr which are converted to R(i-C₃H₇)P(S)Br. Chemical shift values δ p in RR'P(S)Br (R,R' = CH₃, C₂H₅, i-C₃H₇, t-C₄H₉) increase linearly with the number of ß-methyl groups in R and R'. AB₃C₃X-spectra are calculated for i-C₃H₇P-moieties.     

The Kinetics of alkyl radical reactions with aliphatic alcohol glasses as studied by electron spin resonance

Methyl radical reactions with matrix molecules in glasses C₂H₅OH, (CH₂OH)₂, n- and i-C₃H₇OH, n- and i-C₄H₉OH, n- and i-C₅H₁₁OH, C₂D₅OH, and i-C₃D₇OD, and the reactions of ?₂H₅, ?₃H₇, ?₄H₉, ?₅H₁₁ with methanol glasses have been studied. Alkyl radicals were produced by photolysis of diphenylamine–alkylhalide–alcohol mixtures using ultraviolet light. In all cases the alkyl radical decay follows the law c = c₀ exp(-k √t). The √t law should not be associated with alkyl radical diffusion in a matrix. A method of processing the kinetics of those reactions in which one paramagnetic species changes into another with the total concentration being constant and the electron spin resonance spectra of both species overlapping, is described.     

SYNTHESIS OF THE FIRST BENZODISELENAGERMOLES AND ONE SPIROBISDISELENAGERMOLE

Abstract

The first examples of compounds R¹R²GeSe₂C₆H₄R³ (R¹,R²=CH³ C₂H₅, C₃H₂, n-C₄H₉, i-C₅H₁₁, Ph, p-CH₃Ph. R³=H, CH₃, OCH₃) were easily obtained (40–80% yield) from electrophilic cleavage of diselenophenylene zirconocenes by dialkyl or diaryl dichlorogermanes. The synthesis of a spirodi-selenagermole was achieved in the same way using germanium tetrachloride. Analytical data, ¹H and ⁷⁷Se NMR. mass spectra are perfectly consistent with the expected structures.     

Fluordiazadiphosphetidine, 10. Mitt.: Die Reaktion von 1,3-Dialkyl-2,2,2,4,4,4-hexaflouro-1,3,2λ5,4λ5-diazadiphosphetidine mitN-Trimethylsilylmethylamin

Reaction of (RNPF₃)₂ compounds (R=CH₃, C₂H₅,n-C₃H₇,n-C₄H₉,i-C₄H₉) withN-trimethylsilyl-methylamine leads to nucleophilic substitution of one or two fluorine atoms by the methylamino group, depending on the molar amounts of the reactants. In the case ofR=CH₃, two by-products are formed: in the first step a compound with coordination numbers IV, V and VI for the three phosphorus atoms in C₅H₁₇F₇N₅P₃ and in the second step a monospiroflourodiaza-⁵, ⁵-diphosphetidine.

9. Mitteilung:Utvary, K., Kubjacek, M., Varmuza, K. Z. anorg. allg. Chem.458, 281 (1979).     

Organometallic compounds as catalysts in the alternating copolymerization of acrylonitirle with butadiene

The catalytic activity of various organometallic compounds of the Lewis acid type R_mMX_n(M = Zn, Cd, B, Al; R = CH₃,C₂H₅, i-C₄H₉, C₆H₅CH₂, C₆H₅C₂H₄; X = Cl, OCH₃) in the alternating copolymerization of acrylonitrile with butadiene in bulk and in toluene solution has been studied. The activity of the catalyst was found to depend on its acidity, the strength of its M? R bond, and on the type of substituent R. The results obtained have been discussed in terms of the copolymerizability of the acrylonitrile complexed by R_mMX_n and in terms of the effect of the R_mMX_n structure on the initiation rate of the copolymerization.     

Proton and 13C NMR spectra of substituted methyl cyanopropionates: Effects of molecular asymmetry

The proton NMR spectra at 220 MHz of two series of substituted cyanopropionates, have been investigated. In addition the ¹³C spectra at 15 MHz of the series I were also studied. In I, where the R groups are diastereotopic, differences are observed in the proton chemical shifts of the CH₃ groups in R for R = CH₃, C₂H₅, n-C₃H₇, i-C₃H₇, n-C₄H₉, n-C₅H₁₁ and n-C₆H₁₃. In II [R′ = n-C₃H₇, CH(CH₃)₂, CH₂CH(CH₃)₂ and C(CH₃)₃] diastereoisomers are found with substantial differences in chemical shifts between corresponding protons. Coupling constants are interpreted in terms of conformational preferences for certain molecules in both series.     

Structural Organization of Symmetrical Dialkylthiuram Disulfides and Their Cyclic Analogs: X-Ray Diffraction and CP/MAS (13C, 15N) NMR Studies

High-resolution ¹³C and ¹⁵N solid-state NMR spectra were recorded for seven crystalline tetraalkyl-thiuram disulfides and their cyclic analogs of the general formula [R₂NC(S)S]₂ (where R = CH₃, C₂H₅, C₃H₇, and i-C₃H₇ or R₂ = (CH₂)₅, (CH₂)₆, and (CH₂)₄O). The ¹⁵N and ¹³C NMR resonances were assigned to the particular atoms in the compounds studied. Different isotropic ¹⁵N chemical shifts for both dialkyldithiocarbamato groups were interpreted while considering the inductive effects of the alkyl substituents combined with the mesomeric effect of the dithiocarbamato group. X-ray diffraction data were used to refine the molecular structure of bis(cyclohexamethylene)thiuram disulfide and to quantitatively characterize the conformations of the seven-membered N(CH₂)₆ heterocycles.     

Tin(IV) complexes of schiff bases derived from pentane-2,4-dione or 2-hydroxy-1-naphthaldehyde

The 1∶2 molar reactions of tin(IV) chloride with the Schiff bases, CH₃C(OH):CHC(CH₃):NR and 2 HOC₁₀H₆CH:NR′ (where R=C₂H₅,n-C₃H₇ orn-C₄H₉ and R′=C₆H₅, C₂H₅,n-C₄H₉ ort-C₄H₉) have resulted in the synthesis of SnCl₄·(SBH)₂ type derivatives (whereSBH represents the Schiff base molecule). These have been characterized by elemental analysis, conductivity measurements and IR spectral studies.     

Synthesis and gas permeation properties of silicalite-1 zeolite membrane

Ｉｎｏｒｇａｎｉｃｃｅｒａｍｉｃｍｅｍｂｒａｎｅｈａｓｂｅｅｎａｔｔｒａｃｔｅｄｍｏｒｅａｎｄｍｏｒｅａｔｔｅｎｔｉｏｎｉｎｔｈｅｆｉｅｌｄｏｆｍｅｍｂｒａｎｅｓｃｉｅｎｃｅａｎｄｔｅｃｈｎｏｌｏｇｙｄｕｅｔｏｉｔｓｕｎｉｑｕｅｔｈｅｒｍａｌ,ｃｈｅｍｉｃａｌａｎｄｂｉｏｌｏｇｉｃａｌｓｔａｂｉｌｉｔｙ.Ｉｎｔｈｅｌａｓｔｄｅｃａｄｅ,ａｌａｒｇｅｎｕｍｂｅｒｏｆｐａｐｅｒｓｗｅｒｅｐｕｂｌｉｓｈｅｄｏｎｔｈｅｐｒｅｐａｒａｔｉｏｎａｎｄａｐｐｌｉｃａｔｉｏｎｏｆｃｅｒａｍｉｃｍｅｍｂｒａｎｅｓ[1,…     

Quenching of I(2P½) by R-OH compounds. Influence of the alkyl group on the quenching efficiency

The deactivation of I(²P_½) by R-OH compounds (R = H, C_nH_2n+1) was studied using time-resolved atomic absorption at 206.2 nm. The second-order quenching rate constants determined for H₂O, CH₃OH, C₂H₅OH, n-C₃H₇OH, i-C₃H₇OH, n-C₄H₉OH, i-C₄H₉OH, s-C₄H₉OH, t-C₄H₉OH, are respectively, 2.4 ± 0.3 × 10⁻¹², 5.5 ± 0.8 × 10⁻¹², 8 ± 1 × 10⁻¹², 10 ± 1 × 10⁻¹², 10 ± 1 × 10⁻¹², 11.1 ± 0.9 × 10⁻¹², 9.8 ± 0.9 × 10⁻¹², 7.1 ± 0.7 × 10⁻¹², and 4.1 ± 0.4× 10⁻¹² cm³ molec⁻¹ s⁻¹ at room temperature. It is believed that a quasi-resonant electronic to vibrational energy transfer mechanism accounts for most of the features of the quenching process. The influence of the alkyl group and its role in the total quenching rate is also discussed. © 1997 John Wiley & Sons, Inc.