Anionic polymerization of ϵ-caprolactam activated with phosphadiazines

Phenylphosphonyl-N,N′-biscaprolactam (I) and phenylphosphonyl-N,N′-bis(3,5-dimethylpyrazole) (II) were synthesized and found to be very efficient activators for the anionic polymerization of caprolactam when used in combination with strong bases such as sodium caprolactam. Polymers obtained in the presence of I and II had generally higher molecular weights and were less sensitive to thermal degradation upon molding than those whose preparation entailed the use of N-acetyl-caprolactam (III) as an activator. Thermal behavior and tensile properties indicated that the structure of these polyamides differs from that encountered in nylon 6 prepared with conventional anionic catalyst systems.     

Polymerization of α-piperidone with M–AlEt3, MAlEt4, or KAlEt3(piperidone) as catalysts and N-acetyl-α-piperidone as initiator

Low-temperature polymerization of α-piperidone was carried out by using MAlEt₄, KAlEt₃(piperidone), and M–AlEt₃ (where M is Li, Na, or K) as catalysts and N-acetyl-α-piperidone as initiator. The behavior in polymerization of these catalysts was superior to alkali metal or aluminum triethyl, and a polymer having an intrinsic viscosity of 0.8 dl./g. was obtained. Polymerization results and infrared analyses of the metal salts of lactams suggest that a complex, the structure of which was analogous to the one formed from M–AlEt₃, is formed in the case of the alkali metal piperidonate–ethyl aluminum dipiperidonate catalyst system and that it is changed to another complex having a different composition and lower catalytic activity by heat treatment. The infrared absorption band of the metal salts of lactams and of KAlEt₃(piperidone) at 1570–1590 cm.^?1, which is attributable to the C?N group in enolate form, may be considered to be related to the catalytic activities of alkali metals and the polymerizabilities of lactams. Such special catalysts as MAlEt₄, alkali metal–AlEt₃, or KAlEt₃(piperidone) are supposed to suppress the consumption, by alkali metal, of N-acyl-α-piperidone group of growing polymer end. A prolonged polymerization required for obtaining a high molecular weight polymer, even when such catalysts are used, is ascribable to a greater difficulty in re-forming lactam anion from α-piperidone, the basicity of which is higher than that of the other lactams.     

Problems in low-temperature polymerization of lactams with MAlEt4–n (Lac)n as catalyst

The NaAl(Lac)₄-catalyzed polymerization of ε-caprolactam at the medium temperature range (70–150°C) was investigated. The initiation temperature was observed to decrease to about 100°C in the case of a high concentration (such as 2.0 mole-%) of catalyst. Moreover, in the prolonged polymerization of lactams with KAl(Lac)₂Et₂ catalyst, in the absence of initiator, the low activity of aluminum lactamate as initiator was observed. In connection with the polymerization of lactams with MAl(Lac)_nEt_4–n catalyst, the reactivity of MAlEt₄ (where M is Na or K) with N-acetyllactams was investigated. The results imply that no consumption of N-acyllactams by the reaction with MAl(Lac)_nEt_4–n occurs in the course of the low-temperature polymerization of lactams.     

Properties of nylon 6 anionically obtained with NaAl(Lac)4 catalyst and polymerization of ϵ-caprolactam with NaAl(Lac)3(OEt) catalyst

The m-cresol-insoluble polymer of ?-caprolactam obtained with NaAl(Lac)₄ catalyst is converted to a soluble polymer on treatment with dilute (0.1 wt-%) aqueous hydrochloric acid without any accompanying degradation of polymer chain. Aluminum contained in the polymer was not removed completely by extensive extraction with methanol, regardless of the solubilities of the polymers. This fact suggests the existence of two forms of aluminum in the polymer: one contributes to insolubility of the polymer and the other does not. The polymerization behavior in the case of NaAl(Lac)₃(OEt) was somewhat different from that of NaAl(Lac)₄ and of NaAl(Lac)₃(NHBu). These results are considered to reflect a difference in the stability of the Al-O, Al-(Lac), and Al-N bonds in the catalyst.     

Low-temperature polymerization of lactams by using as catalyst the salt derived from NaAlEt4 and monomer and with several compounds as initiator

Low-temperature polymerization of α-pyrrolidone, α-piperidone, and ?-caprolactam was examined by using the salts derived from NaAlEt₄ and monomer, sodium lactamates, or the salt derived from AlEt₃ and monomer as catalyst and with N-acetyl lactams, ethyl acetate, or lactones as initiator. Sodium lactamate catalyst gave unsatisfactory results in the cases of ethyl acetate or lactones initiators, and gave the following order for the relative efficiency of initiators: N-acetyl lactam > ?-caprolactone ≥ ethyl acetate > β-propiolactone. The polymerization results obtained by the salt from NaAlEt₄ catalyst–ethyl acetate initiator system were nearly the same as those with N-acetyl lactam. The increases in the degree of polymerization and in the yield of polymer were observed in case of the salt from NaAlEt₄ catalyst-lactone initiator system, particularly in the cases of α-piperidone and ?-caprolactam. Also an incorporation of initiator into polymer chain was observed.     

On the Existence of Two New Mixed-Alkali Cyclohexaphosphates: Li3Na3P6O18 · 12 H2O and Li3K3P6O18 · H2O

Reaction of (CH₃)₂ Te with CF₃I: Preparation and Properties of [(CH₃)₂TeCF₃]I The irradiation of a mixture of (CH₃)₂ Te and CF₃I at low temperature yields [(CH₃)₂TeCF₃]I. From the thermal decomposition as well as in polar solvents CH₃TeCF₃ and CH₃I are formed. Attempts to prepare bis- or tris(trifluoromethyl)tellurium compounds from these reactions failed. [(CH₃)₂TeCF₃]I reacts with salts or acids to form many new derivatives of the composition [(CH₃)₂TeCF₃]X (X = Cl, NO₃, 1/2 SO₄, OCOCH₃, OCOCF₃, B(C₆H₅)₄, OC₆H₂(NO₂)[₃].     

Studies on julimycins—VI The structures of julichromes Q1·2, Q2·2, Q3·5, Q3·5, Q4·5, Q2·5 and Q5·5

Julichromes Q_1·2 and Q_2·2 are identified as the dehydration products of julimycin B-II. The structures of julichromes, which commonly have a new anthraquinonyl Q₅ unit, are confirmed by their preparation from known julichromes. The conversion reaction, Q₂ → Q₅, which involves an intra-molecular redox is probably concerned in the biosynthesis of this unit.     

Kinetics and mechanism of stereospecific polymerization of methyl methacrylate with VOCl3–AlEt2Cl catalyst system

Methyl methacrylate was polymerized at 40°C with VOCl₃–AlEt₂Cl catalyst system in n-hexane. The rate of polymerization was proportional to catalyst and monomer concentration at Al/V ratio of 2 and overall activation energy of 9.25 kcal/mole support a coordinate anionic mechanism of polymerization. The catalytic activity and stereospecificity of this catalyst system is discussed in comparison with that of VOCl₃–AlEt₃ catalyst system.     

Syntheses and Structures of Na2Mg3(OH)2(SO4)3·4H2O and K2Mg3(OH)2(SO4)3·2H2O

The crystal structures of Na₂Mg₃(OH)₂(SO₄)₃ · 4H₂O and K₂Mg₃(OH)₂(SO₄)₃ · 2H₂O, were determined from conventional laboratory X‐ray powder diffraction data. Synthesis and crystal growth were made by mixing alkali metal sulfate, magnesium sulfate hydrate, and magnesium oxide with small amounts of water followed by heating at 150 °C. The compounds crystallize in space group Cmc2₁ (No. 36) with lattice parameters of a = 19.7351(3), b = 7.2228(2), c = 10.0285(2) Å for the sodium and a = 17.9427(2), b = 7.5184(1), c = 9.7945(1) Å for the potassium sample. The crystal structure consists of a linked MgO₆–SO₄ layered network, where the space between the layers is filled with either potassium (K⁺) or Na⁺‐2H₂O units. The potassium‐bearing structure is isostructural to K₂Co₃(OH)₂(SO₄)₃ · 2(H₂O). The sodium compound has a similar crystal structure, where the bigger potassium ion is replaced by sodium ions and twice as many water molecules. Geometry optimization of the hydrogen positions were made with an empirical energy code.     

Cationic polymerization of ϵ-caprolactone in the presence of diols via activated monomer mechanism

The kinetics of noncatalytic and catalytic interaction of ϵ-caprolactone (ϵ-CL) with a variety of diols in the presence of onium-type catalysts as well as the resulting products structure were investigated. The phenomenon of the direction change of the lactone ring opening during the interaction with hydroxyl-containing compounds of different functionality was discovered. The features of the reactions investigated were discussed and their kinetic parameters were determined.     

Zur thermischen Entwässerung von K2AlF5 · H2O

On the Thermal Dehydration of K₂AlF₅ · H₂O The thermal dehydration of K₂AlF₅ · H₂O was investigated by X-ray diffraction and thermal analysis. Two dehydrat phases were detected. K₂AlF₅ (II) is orthorhombic (a = 758 pm, b = 1257 pm, c = 1044 pm) and isotypical with α-(NH₄)₂FeF₅ (cis-connected chains). The tetragonal phase is formed by a topotactic mechanism. This phase is instable and tends to rehydrate or to transform into the more stable orthorhombic phase. The irreversible transformation from I into II is connected with an exothermal DTA effect.     

Kristallstruktur von Na5P3O10 · 6 H2O

Crystal Structure of Na₅P₃O₁₀ · 6 H₂O Na₅P₃O₁₀ · 6 H₂O crystallizes triclinic in P1 with a = 1 037.0(2), b = 984.8(4), c = 761.5(3) pm; α = 92.24(7)°, β = 94.55(9), γ = 90.87(6)°; Z = 2. The structure has been determined from fourcycle diffractometer data (2 089 independent reflections, R = 0.053). All hydrogen positions have been taken from a weighted difference-fourier-syntheses. Na₅P₃O₁₀ · 6 H₂O forms colorless, plate-like crystals, which are twinned systematically parallel (001) and can be divided mechanically into single-crystalline portions.     

Stereospecific polymerization of isobutyl vinyl ether by AIR3–VCl3·LiCl catalyst. II. Effects of polymerization conditions on polymerization

The effect of polymerization conditions such as aging time of the catalyst, polymerization temperature, polymerization time, monomer concentration, and catalyst concentration on the polymerization of isobutyl vinyl ether was intensively studied by using the VCI₃·LiCl–Al(i-Bu)₃ system at an Al(i-Bu)/VCl₃·LiCl ratio of 6 at which the cationic polymerization by VCl₃·LiCl is sufficiently depressed. About 10 min aging of the catalyst in the presence of monomer yields a fairly stable catalytie system. The optimum polymerization temperature is around 30°C. The conversion increased with increasing monomer concentration, whereas the stereospecificity of polymerization decreased. Unexpectedly, the conversion decreased as total catalyst concentration increased. This phenomenon is explained by considering the deactivation of catalytic sites by the excess of Al(i-Bu)₃. A reasonable mechanism from kinetic considerations is that two molecules of Al(i-Bu)₃ deactivate the catalytic site in an equilibrium reaction. This deactivation is understandable by considering that the coordination of two molecules of Al(i-Bu)₃ will occupy all the coordination positions of vanadium, so that there is no room for coordination of monomer coming to the catalytic site.     

K2B4O7-Na2B4O7-Li2B4O7-H2O 四元体系15℃介稳相平衡研究

采用等温蒸发平衡法研究了四元体系K2B4O7-Na2B4O7-Li2B4O7-H2O15℃时的介稳相平衡及平衡液相的物化性质(密度,粘度,电导率,折光率,pH)。根据实验数据绘制了相图,相图中有一个共饱点E,三条单变度曲线E3F,E2F,E1F;三个平衡固相分别为：K2B4O7•4H2O,Na2B4O7•10H2O和Li2B2O4•16H2O;硼酸钾具有最大溶解度,硼酸钠具有最小溶解度。同时,根据试验数据绘制了组成－物化性质关系图,从图可见溶液的密度,粘度和折光率均随着溶液浓度的增大而逐渐增大,在共饱和点F处达到最大值,而溶液的pH值和电导率却随着溶液浓度的增大呈总体下降的趋势。     

Cerous sodium nitrate monohydrate,Na2Ce(NO3)5·H2O

The title compound, disodium cerium pentanitrate monohydrate, was synthesized from a nitric acid solution of Ce(NO₃)₃·6H₂O and NaNO₃, and its structure has been determined from single‐crystal X‐ray diffraction data. The structure is built from isolated chains of irregular icosahedral [Ce(NO₃)₆]^3? anions. Na atoms and water mol­ecules are located between the chains. The Na coordination polyhedra, in the form of a square antiprism or a monocapped square antiprism, share common vertices and contribute to the formation of a three‐dimensional network. Ten nitrate groups act as bridging ligands.     

Tetrahedral [Tt4]4– Zintl Anions Through Solution Chemistry: Syntheses and Crystal Structures of the Ammoniates Rb4Sn4·2NH3, Cs4Sn4·2NH3, and Rb4Pb4·2NH3

The crystalline isotypic solvates Rb₄Sn₄·2NH₃, Cs₄Sn₄·2NH₃, and Rb₄Pb₄·2NH₃ have been synthesized using the direct reduction of elemental tin or tetraphenyltin, respectively, with heavier alkali metals or the dissolution of the binary phase RbPb in liquid ammonia. These compounds contain the cluster ions [Sn₄]^4– or [Pb₄]^4– respectively. This is the first time that[Tt₄]^4– ions (Tt = tetrels) are detected as result of a solution reaction. The accommodation of the ammonia molecules, which build up ion‐dipole interactions to alkali metal cations, requires some modifications of the crystal structures compared to the binary phases RbSn, CsSn, and RbPb. The tetrahedral [Tt₄]^4– anions have a slightly lower coordination by Rb⁺ or Cs⁺ cations and, furthermore, the intercluster distances show a remarkable increase.     

Al(Cap)3 as initiator in the anionic polymerization of ε-caprolactam at high temperature

Mechanism for polymerization of ε-caprolactam in the presence of both sodium and aluminum caprolactamate was investigated at 171°C. The role of Al(Cap)₃ as an initiator was revealed. The apparent rate constant of propagation reaction decreased with the increase in the concentration of Al(Cap)₃, as the two different metal salts interact even at 171°C. The activation energy of the overall polymerization reaction with this catalyst system was estimated to be 41.18 kcal/mole.     

Lanthanide complexes of 2,2′‐oxydi­acetate: Na5[M(C4H4O5)3](BF4)2·6H2O (M = Nd,Sm or Gd)

The three title complexes, namely pentasodium tris(2,2′‐oxydi­acetato)­neodymium(III) bis­(tetra­fluoro­borate) hexahydrate and its samarium(III) and gadolinium(III) analogues, (I)–(III), respectively, are isomorphous and isostructural and have crystallographic D₃ symmetry. The lanthanide metal ions are nine‐coordinate, binding to three O atoms of three oxodi­acetate ligands. One Na⁺ ion is octahedrally coordinated to six O atoms and the other Na⁺ ion is octahedrally coordinated to four O atoms and two F atoms. The structure is effectively an infinite three‐dimensional polymer, consistent with the exceptional crystal quality. The racemic solutions spontaneously resolve on crystallization. For the individual crystals selected for structural analysis, the Nd and Sm complexes have the Λ configuration, while the Gd complex has the Δ configuration. The lanthanide–oxy­gen distances show the expected contraction of ca 0.02 Å with increasing atomic number for the lanthanide metal.     

[(C2H5)3NH]2Sn3Se7 · 0,25 H2O und [(C3H7)2NH2]4Sn4Se10 · 4 H2O

Synthesis, Structure, and Properties of Some Selenidostannates. II. [(C₂H₅)₃NH]₂Sn₃Se₇ · 0,25 H₂O and [(C₃H₇)₂NH₂]₄Sn₄Se₁₀ · 4 H₂O The new selenidostannate hydrates [(C₂H₅)₃NH]₂Sn₃Se₇ · 0.25 H₂O ( I ) and [(C₃H₇)₂NH₂]₄Sn₄Se₁₀ · 4 H₂O ( II ) were synthesized from an aqueous suspension of triethylammonium (tripropylammonium), tin, selenium I and in addition sulfur II at 130 °C. I crystallizes at ambient temperature in the monoclinic space group P2₁/n (a = 2069,3(4) pm, b = 1396,6(3) pm, c = 2342,8(5) pm, β = 114,68(3)°, Z = 8) and is characterized by two different anions, chains from edge‐sharing [Se₃Se₇]^2– units and nets from trigonal SnSe₅ bipyramids. II crystallizes at ambient temperature in the tetragonal space group I4₁/amd (a = 2150,0(3) pm, c = 1174,4(2) pm, Z = 4) and contains adamantane like [Sn₄Se₁₀]^4–‐cages. The UV‐VIS spectra of the selenidostannates demonstrate that the absorption edges red shift as the dimensionality of the compounds is increased.     

Complexation of the 2, 4, 6‐Triallyloxy‐1, 3, 5‐triazine with Copper(I,II) Chlorides. Syntheses and Crystal Structures of [CuCl2·2C3N3(OC3H5)3], [Cu7Cl8·2C3N3(OC3H5)3], and [Cu8Cl8·2C3N3(OC3H5)3]·2C2H5OH

Interaction of copper(II) chloride with 2, 4, 6‐triallyloxy‐1, 3, 5‐triazine leads to formation of copper(II) complex [CuCl₂·2C₃N₃(OC₃H₅)₃] ( I ). Electrochemical reduction of I produces the mixed‐valence Cu^{I, II} π, σ‐complex of [Cu₇Cl₈·2C₃N₃(OC₃H₅)₃] ( II ). Final reduction produces [Cu₈Cl₈·2C₃N₃(OC₃H₅)₃]·2C₂H₅OH copper(I) π‐complex ( III ). Low‐temperature X‐ray structure investigation of all three compounds has been performed: I : space group P1¯, a = 8.9565(6), b = 9.0114(6), c = 9.7291(7) Å, α = 64.873(7), β = 80.661(6), γ = 89.131(6)°, V = 700.2(2) ų, Z = 1, R = 0.0302 for 2893 reflections. II : space group P1¯, a = 11.698(2), b = 11.162(1), c = 8.106(1) Å, α = 93.635(9), β = 84.24(1), γ = 89.395(8)°, V = 962.0(5) ų, Z = 1, R = 0.0465 for 6111 reflections. III : space group P1¯, a = 8.7853(9), b = 10.3602(9), c = 12.851(1) Å, α = 99.351(8), β = 105.516(9), γ = 89.395(8), V = 1111.4(4) ų, Z = 1, R = 0.0454 for 4470 reflections. Structure of I contains isolated [CuCl₂·2C₃N₃(OC₃H₅)₃] units. The isolated fragment of I fulfils in the structure of II bridging function connecting two hexagonal prismatic‐like cores Cu₆Cl₆, whereas isolated Cu₆Cl₆(CuCl)₂ prismatic derivative appears in III . Coordination behaviour of the 2, 4, 6‐triallyloxy‐1, 3, 5‐triazine moiety is different in all the compounds. In I ligand moiety binds to the only copper(II) atom through the nitrogen atom of the triazine ring. In II ligand is coordinated to the Cu^II‐atom through the N atom and to two Cu^I ones through the two allylic groups. In III all allylic groups and nitrogen atom are coordinated by four metal centers. The presence of three allyl arms promotes an acting in II and III structures the bridging function of the ligand moiety. On the other hand, space separation of allyl groups enables a formation of large complicated inorganic clusters.