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.     

KRISTALLSTRUKTUR VON BIS(DIETHYLDITHIOCARBAMATO)-PHENYLPHOSPHAN UND SYNTHESE EINIGER MONO- UND BIS(DIORGANYLDITHIOCARBAMATO)PHOSPHANE

Abstract

By reaction of organylchlorophosphanes with sodium dithiocarbamates compounds of the type RP(S₂CNR₂′)₂ with R = CH₃, C₆H₅; R' = CH₃, C₂H₅, CH(CH₃)₂, C₆H₅ and of the type (C₆H₅)₂PS₂CNR₂′ with R' = CH₃, CH(CH₃)₂ as well as compound [(C₆H₅)₂PS₂CN(CH₃)CH₂-]₂ are obtained. The crystal structure of C₆H₅P(S₂CN(C₂H₅)₂)₂ shows that the trend from bidentate to monodentate bonding of the dithiocarbamate ligands in the homologous series RE(S₂CN(C₂H₅)₂)₂; E = Bi, Sb, As, P is continued for E = P.

Durch Umsetzung der jeweiligen Chlorophosphane mit den entsprechenden Natriumdithiocarbamaten können folgende Verbindungen erhalten werden: Verbindungen des Typs RP(S₂CNR₂′)₂ mit R = CH₃, C₆H₅; R' = CH₃, C₂H₅, CH(CH₃)₂, C₆H₅; Verbindungen des Typs (C₆H₅)₂PS₂CNR₂′ mit R' = CH₃, CH(CH₃)₂ sowie [(C₆H₅)₂PS₂CN(CH₃)CH₂-]₂. Die Kristallstruktur von C₆H₅P(S₂CN(C₂H₅)₂)₂ zeigt, daß sich der Trend zu schwächer ausgeprägter zweizähniger Bindungsweise der Dithiocarbamatliganden in der homologen Reihe RE(S₂CN(C₂H₅)₂)₂; E = Bi, Sb, As, P für E = P fortsetzt.     

SYNTHESIS AND CHARACTERISATION OF DIORGANOANTIMONY(III) COMPLEXES OF THIOSEMICARBAZONES

Abstract

The interaction of the sodium salts of thiosemicarbazones with diphenylantimony chloride in 1:1 molar ratio in benzene solution lead to the formation of derivatives, Ph₂Sb[SC(NH₂)NN: C(R)R′] where R = H; R′ [dbnd] C₆H₅, CH₃OC₆H₄, C₆H₅CH[dbnd]CH, and R′ [dbnd] CH₃; R′[dbnd]C₆H₅, CH₃OC₆H₄, C₆H₄CH₃, respectively. The resulting complexes have been characterised on the basis of elemental analyses and molecular weight determination. The mode of bonding of the ligands with the metal atom has been proposed on the basis of I.R., ¹H and ¹³C NMR studies. All these ligands are found to behave as monofunctional bidentate moiety in these complexes.     

Gas sorption and characterization of poly(ether‐b‐amide) segmented block copolymers

The solubilities of He, H₂, N₂, O₂, CO₂, CH₄, C₂H₆, C₃H₈, and n‐C₄H₁₀ were determined at 35°C and pressures up to 27 atmospheres in a systematic series of phase separated polyether–polyamide segmented block copolymers containing either poly(ethylene oxide) [PEO] or poly(tetramethylene oxide) [PTMEO] as the rubbery polyether phase and nylon 6 [PA6] or nylon 12 [PA12] as the hard polyamide phase. Sorption isotherms are linear for the least soluble gases (He, H₂, N₂, O₂, and CH₄), convex to the pressure axis for more soluble penetrants (CO₂, C₃H₈, and n‐C₄H₁₀) and slightly concave to the pressure axis for ethane. These polymers exhibit high CO₂/N₂ and CO₂/H₂ solubility selectivity. This property appears to derive mainly from high carbon dioxide solubility, which is ascribed to the strong affinity of the polar ether linkages for CO₂. As the amount of the polyether phase in the copolymers increases, gas solubility increases. The solubility of all gases is higher in polymers with less polar constituents, PTMEO and PA12, than in polymers with more polar PEO and PA6 units. CO₂/N₂ and CO₂/H₂ solubility selectivity, however, are higher in polymers with higher concentrations of polar repeat units. The sorption data are complemented with physical characterization (differential scanning calorimetry, elemental analysis, and wide angle X‐ray diffraction) of the various block copolymers. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 2463–2475, 1999     

Substituted Diorganotin(IV) O,O’-Alkylene Dithiophosphates: Synthesis and Spectral Aspects

Six new substituted diphenyltin(IV) O,O′-alkylene dithiophosphates, (C₆H₅)₂Sn(X)S(S) POGO [G = —CH₂C(CH₃)₂CH₂—, X = Cl (1), SCN (3), ClO₄ (5); G = —CH₂C (C₄H₉)(C₂H₅)CH₂—, X = Cl (2), SCN (4), ClO₄ (6)], were synthesized by the reaction of the corresponding ammonium salts of the O,O’-alkylene dithiophosphates with an appropriate organotin(IV) chloride. The compounds were characterized on the basis of elemental and spectral analyses (ESI mass spectrometry, IR, ¹H, ¹³C, ³¹P, and ¹¹⁹Sn NMR). The presence of a four-coordinated Sn atom and monodentate O,O’-alkylene dithiophosphate moiety in compounds 1–4 as well as bidentate O,O’-alkylene dithiophosphate unit in compounds 5,6 is established.     

Thermal properties of poly(tertiary phosphine oxides)

DTA and TGA (in air and in nitrogen) are presented for the poly(tertiary phosphine oxides), C₆H₅[(C₆H₅)P(O)CH₂CH₂]_nP(O)(C₆H₅)₂, where n = 1, 2, or 3.     

Preparation and thermal properties of asymmetrically substituted poly(silylenemethylene)s

Poly(silylenemethylene)s of the types [SiMeRCH₂]_n and [SiHRCH₂]_n were prepared by the ring-opening polymerization (ROP) of 1,3-disilacyclobutanes (DSCBs) containing n-alkyl substituents, such as C₂H₅, n-C₃H₇, n-C₄H₉, n-C₅H₁₁, and n-C₆H₁₃, or a phenyl group on the Si. These new polymers include a monosilicon analog of poly(styrene), [SiHPhCH₂]_n. Improved synthesis routes to the DSCB monomers were developed which proceed through Grignard ring closure reactions on alkoxy-substituted chlorocarbosilanes. All of these asymmetrically substituted polymers were obtained in high molecular weight form, except for [SiHPhCH₂]_n. The configurations of all of the polymers were found to be atactic. The aryl-substituted polymers have higher glass transition temperatures (T_gs) and thermal stability than those of the alkyl-substituted poly(silylenemethylene)s. Unlike the polyolefins of the type [C(H)(R)CH₂]_n, where T_g drops continuously from R = Me to n-Hex, the T_gs of the n-C_nH_2n+1 (n = 2–6)-substituted [SiMeRCH₂]_n PSM's appear to reach a maximum (at −61°C) for the R = n-Pr-substituted polymer. Moreover, where it was possible to make direct comparisons among similarly substituted atactic polymers, all of the poly(silylenemethylene)s were found to have lower T_gs than their all-carbon analogs. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 3193–3205, 1997     

Sulfenamides as ligands in transition metal chemistry Pentacarbonyl(Sulfenamide)Chromium(0) Complexes

The complexes Cr(CO)₅(R′SNR₂) [R′ = CH₃; NR₂ = N(CH₃)₂, N(C₄H₈)O. R′ = C₆H₅; NR₂ = N(CH₃)₂, N(C₄H₄)O, N(CH₂? C₆H₅)₂, N(C₆H₁₁)₂] have been prepared by reaction of the sulfenamides with Cr(CO)₅ · THF and characterized by analytical and spectroscopic methods. The IR, ¹H-NMR, UV-VIS, and mass spectra of the complexes support the coordination of the sulfenamide via the sulfur atom. π-acceptor abilities of sulfenamides in the prepared coordination compounds, determined from IR and UV-VIS data, were compared with those of other divalent sulfur conpounds.     

Triphenylantimony(v) Derivatives of 2,2-Disubstituted Benzothiazoline Ligands: Synthetic and Spectroscopic Studies

The reactions of triphenylantimony(v) isopropoxide with 2,2-disubstituted benzothiazolines in a 1:2 molar ratio in refluxing benzene solution yielded the corresponding triphenylantimony(v) derivatives (1–5) of the type Ph₃Sb[SC₆H₄N: C(R)CH₂C(O)R']₂, [Where, R═CH₃, R'═CH₃(1); R═CH₃, R'═C₆H₅(2); R═CH₃, R'═4-CH₃C₆H₄(3); R═CH₃, R'═4-ClC₆H₄(4); and R═CF₃, R'═C₆H₅(5)]. All of these newly synthesized derivatives have been characterized by elemental analyses and molecular weight measurements as well as IR and NMR [¹H and ¹³C] spectral studies. On the basis of spectral data, seven-coordination around central antimony atom has been assigned to these derivatives.     

Gas sorption,diffusion, and permeation in poly(dimethylsiloxane)

The permeability of poly(dimethylsiloxane) [PDMS] to H₂, O₂, N₂, CO₂, CH₄, C₂H₆, C₃H₈, CF₄, C₂F₆, and C₃F₈, and solubility of these penetrants were determined as a function of pressure at 35 °C. Permeability coefficients of perfluorinated penetrants (CF₄, C₂F₆, and C₃F₈) are approximately an order of magnitude lower than those of their hydrocarbon analogs (CH₄, C₂H₆, and C₃H₈), and the perfluorocarbon permeabilities are significantly lower than even permanent gas permeability coefficients. This result is ascribed to very low perfluorocarbon solubilities in hydrocarbon‐based PDMS coupled with low diffusion coefficients relative to those of their hydrocarbon analogs. The perfluorocarbons are sparingly soluble in PDMS and exhibit linear sorption isotherms. The Flory–Huggins interaction parameters for perfluorocarbon penetrants are substantially greater than those of their hydrocarbon analogs, indicating less favorable energetics of mixing perfluorocarbons with PDMS. Based on the sorption results and conventional lattice solution theory with a coordination number of 10, the formation of a single C₃F₈/PDMS segment pair requires 460 J/mol more energy than the formation of a C₃H₈/PDMS pair. A breakdown in the geometric mean approximation of the interaction energy between fluorocarbons and hydrocarbons was observed. These results are consistent with the solubility behavior of hydrocarbon–fluorocarbon liquid mixtures and hydrocarbon and fluorocarbon gas solubility in hydrocarbon liquids. From the permeability and sorption data, diffusion coefficients were determined as a function of penetrant concentration. Perfluorocarbon diffusion coefficients are lower than those of their hydrocarbon analogs, consistent with the larger size of the fluorocarbons. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 415–434, 2000     

Density and viscosity studies of poly(ethylene-oxide) alkyl alcohols

Density and viscosity of binary systems water-nonionic surfactants poly(ethylen-oxide) alkyl alcohols type, [C_nH_2n+1(OCH₂CH₂)_mOH, C_nE_m], have been studied. The partial molar volumes in the dilute solution range and the viscosity B-coefficients were calculated. The nonionic surfactants partial molar volumes were compared with those of ethylene glycol and poly(ethylenglycol) (PEG). The comparison shows that the ethoxy unit volume, (OCH₂CH₂), seems to be independent of the particular system. The consequences of this are discussed. A model for interpreting the experimental B values has been proposed. The model treats the macroscopic viscosity as the superimposition of different local effects. The following surfactants have been considered: C₅E₁, C₅E₂, C₆E₁, C₆E₂, C₆E₃, C₆E₄.     

Synthesis,structural characterization,and in vitro antimicrobial properties of salicylate and pyrazoline complexes of bismuth(III)

Displacement reactions of dichlorobismuth(III)pyrazolinates with oxygen donors such as sodium salicylate and acetate in 1?:?1 and 1?:?2 molar ratio in refluxing anhydrous benzene yields (C₁₂H₁₅N₂OX)Bi(C₆H₄O₃), (CH₃COO)BiCl(C₁₅H₁₂N₂OX), and (CH₃COO)₂Bi(C₁₅H₁₂N₂OX) [C₁₂H₁₅N₂OX?=?3(2′-hydroxyphenyl)-5-(4-X-substituted phenyl) pyrazoline X?=?H in 1,5,9, CH₃ in 2,6,10, OCH₃ in 3,7,11, and Cl in 4,8,12, respectively, (C₆H₄O₃)?=?salicylate and (CH₃COO)?=?acetate]. Newly synthesized derivatives are brown solids, soluble in organic solvents like benzene, chloroform, and acetone. The compounds have been characterized by elemental analyses (C, H, N, Cl, and Bi), molecular weight measurements, and spectral (IR, ¹H NMR, ¹³C NMR) studies. The (C₁₂H₁₅N₂OX) and (C₆H₄O₃) are bidentate while (CH₃COO) is monodentate to bismuth(III), leading to a distorted trigonal bipyramidal structure. The complexes were screened against different bacteria and fungi showing potential antibacterial and antifungal activities.     

Syntheses,structures, and luminescent properties of Zn(II) and Cd(II) complexes: 3-D supramolecules based on 2,6-bis(imino)pyridine ligands constructed by hydrogen bonding interactions

Six 5-coordinate 2,6-bis(imino)pyridine metal complexes, [2,6-(ArN=CMe)₂C₅H₃NMCl₂ · nCH₃CN] (Ar = 4-MeC₆H₄, M = Zn, n = 0.5, Zn1, M = Cd, n = 1, Cd1; Ar = 2,6-Et₂C₆H₃, M = Zn, n = 0.5, Zn2, M = Cd, n = 0.5, Cd2; Ar = 2,4,6-Me₃C₆H₂, M = Zn, n = 1, Zn3, M = Cd, n = 1, Cd3), were synthesized in acetonitrile by the reactions of the corresponding bis(imino)pyridines with ZnCl₂ or CdCl₂ · 2.5H₂O, respectively. The structures of Zn1–Zn3 and Cd1–Cd3 were determined by the single-crystal X-ray diffraction. In all complexes, the ligand is tridentate with further coordination by two chlorides, resulting in a distorted trigonal bipyramid. All complexes self-assemble through hydrogen bonding interactions to form a 3-D supramolecular structure. At 298 K in dichloromethane, all complexes have blue luminescent emissions at 405–465 nm, which can be attributed to ligand-centered π* → π transitions. The zinc and cadmium centers play a key role in enhancing fluorescent emission of the ligands.     

ÜBER EINIGE REAKTIONEN DER DIALKYLBENZYLPHOSPHINIMIDE

Abstract

Dialkylbenzylphosphine imides C₆H₅CH₂–PRR′[dbnd]N″ (R, R′ = CH₃, C₂H₅; R″ = H, CH₃, Si(CH₃)₃ react with aliphatic and aromatic aldehydes in benzene solution on heating to 80°C directly and in high yields according to a Horner-Wittig-reaction with formation of an olefine whereas ketones like benzophenone and acetophenone only perform an O/NR″ exchange (R″ = H).

Dialkylbenzylphosphinimide C₆H₅CH₂–PRR′[dbnd]N″ mit R, R′ = CH₃, C₂H₅ und R″ = H, CH₃, Si(CH₃)₃ reagieren mit aliphatischen und aromatischen Aldehyden in benzolischer Lösung beim Erwärmen auf 80°C direkt und mit hohen Ausbeuten im Sinne einer Horner-Wittig-Reaktion unter Olefinbildung, während sich mit Ketonen wie Benzophenon oder Acetophenon nur ein O/NR″-Austausch (R″ = H) vollzieht.     

Disubstituted diphenyldithiophosphates of cadmium: synthesis,characterization, and single-crystal X-ray structure

A series of new disubstituted diphenyldithiophosphate complexes of cadmium [{(ArO)₂PS₂}₂Cd] (9–12) have been isolated in aqueous media while their donor stabilized adducts [{(ArO)₂PS₂}₂Cd·2C₅H₅N] (13–16) [(Ar = 2,4-(CH₃)₂C₆H₃, 2,5-(CH₃)₂C₆H₃, 3,4-(CH₃)₂C₆H₃ and 3,5-(CH₃)₂C₆H₃)] have been isolated in chloroform. These newly synthesized complexes were characterized by elemental analyses, IR and NMR (¹H, ¹³C and ³¹P) spectroscopic analyses. The dithiophosphate ligands are coordinated bidentate to the cadmium ion via the two thiolate sulfurs. The compounds [{(3,5-CH₃)₂C₆H₃O}₂PS₂HNEt₃] (4) and [{(3,5-CH₃)₂C₆H₃O}₂PS₂]₂Cd(NC₅H₅)₂ (16) crystallize in the monoclinic system with space group P2₁/c. Single-crystal X-ray analysis of 4 reveals that phosphorus of the anion is tetrahedrally bonded to two S and two O atoms. The structure is stabilized by cation–anion N–H?S intermolecular hydrogen bond interactions. In 16, two diphenyldithiophosphate ions are bidentate with both sulfurs coordinated to cadmium. Each forms a four-membered chelate ring in the equatorial plane. Two pyridines are axially coordinated to cadmium leading to octahedral geometry. The thermal properties of this complex have also been examined by combined DTA/DTG thermal analyses.     

Syntheses,spectroscopic characterizations and crystal structures of diorganotin(IV)-oxo-carboxylates with 2-pyrazinecarboxylic acid or (2-pyrimidylthio)acetic acid

Eight diorganotin(IV)-oxo-carboxylates {[R₂Sn(O(O)CR′)]₂O}₂?·?Y (R′?=?C₄H₃N₂Y?= H₂OR?=?ⁿBu 1, Y?=?0 R?=?Me 2, Y?=?0 R?=?C₆H₅ 3, Y?=?0 R?=?C₆H₅CH₂ 4; R′?=?CH₂SC₄H₃N₂-2,6Y?=?0 R?=?ⁿBu 5, Y?=?CH₂Cl₂R?=?Me 6, Y?=?0 R?=?C₆H₅ 7, Y?=?0 R?= C₆H₅CH₂ 8) have been prepared in 1?:?1 molar ratios by reactions of diorganotin(IV) oxide with 2-pyrazinecarboxylic acid or (2-pyrimidylthio)acetic acid, respectively. All the complexes are characterized by elemental analysis, IR, ¹H NMR and ¹³C NMR spectra. Except for 2, 4 and 7, the complexes are also characterized by X-ray crystallography diffraction analyses, which reveal that the complexes adopt the familiar dicarboxylato tetraorganodistannoxane structural mode. Among them, the evident difference is that weak intramolecular interactions between Sn and N atoms are recognized in complexes 1 and 3. However, for complex 5 two different coordination modes are found in the same lattice.     

Physicochemical properties and complexing ability of <Emphasis Type="Italic">N</Emphasis>-(2-ethylhexanoyl)-<Emphasis Type="Italic">N</Emphasis>′-sulfonylhydrazines

The effect of substituent at the sulfonyl group on the physicochemical properties and complexing ability of the sulfonyl derivatives of 2-ethylhexanoic acid hydrazide of the general formula C₄H₉CH(C₂H₅)C(O)·NHNHSO₂C₆H₅R [R = H, CH₃, NO₂, NHC(O)CH₃, Cl] with respect to Cu(II), Co(II), and Ni(II) ions was studied.     

Reaktionen von Lanthanoidhalogeniden mit Alkalibenzylverbindungen. Darstellung und Kristallstrukturen von [(tmeda)(C6H5CH2)2Y(μ-Br)2Li(tmeda)], [(tmeda)2SmBr(μ-Br)2Li(tmeda)] und [(dme)2SmBr(μ-Br)]2

Reactions of Lanthanide Halides with Alkalibenzyl Compounds. Synthesis and Crystal Structures of [(tmeda)(C₆H₅CH₂)₂Y(μ-Br)₂Li(tmeda)], [(tmeda)₂SmBr(μ-Br)₂Li(tmeda)] and [(dme)₂SmBr(μ-Br)]₂ Alkali-benzyl compounds react via a metathesis reaction with lanthanide halides to benzyl complexes of the rare earths. Reaction of [(C₆H₅CH₂)Li(tmeda)] with YBr₃ leads to the complex [(tmeda)Y(C₆H₅CH₂)₂ (μ-Br)₂Li(tmeda)] 1 , in which Yttrium and lithium are linked via two bromide bridges. However, the reaction of [(C₆H₅CH₂)Li(tmeda)] with SmBr₃ in toluene/tmeda leads under reduction of the Sm ion to the compound [(tmeda)₂SmBr(μ-Br)₂Li(tmeda)] 2 . 2 reacts with DME to yield the dimeric compound [(dme)₂SmBr(μ-Br)]₂ 3 . The structures of 1 – 3 were determined by X-ray single crystal structure analysis:

• 1: Space group P2₁/c, Z = 4, a = 829.5(6) pm, b = 1477.9(11) pm, c = 2575.0(10) pm, β = 92.03(6)°,
• 2: Space group P2₁, Z = 2, a = 954,7(3) pm, b = 1338.5(6) pm, c = 1244.9(5) pm, β = 107.51(3)°,
• 3: Space group P1 , Z = 1, a = 797.2(7) pm, b = 818.3(7) pm, c = 1169.7(8) pm, α = 100.96(6)°, β = 92.03(6)°, γ = 91.75(7)°.

     

4,5-dihydro-6h-pyrrolo[1,2,3-d,e]quinoxalin-5-ones

The synthesis of 1-R¹-2-R²-8-R³-4,5-dihydro-6H-pyrrolo[1,2,3-d,e]quinoxalin-5-one derivatives (where R¹ = CH₃, C₂H₅; R² = CH₃, COOC₂H₅; R³ = H, CH₃, C₂H₅O, Cl, Br) is described. The physicochemical properties of these derivatives were also studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 839–841, June, 1979.