Simultaneous hydrothermal decomposition and methylation: High resolution gas chromatography–mass spectrometry for polymer characterization

High speed hydrothermal decomposition of some chemically inert condensation polymers in alkaline solutions under near-critical pressures and temperatures has been investigated by on-line Curie-point heating–high resolution GC-MS. The technique also involves simultaneous methylation with tetramethylammonium hydroxide in a 1 mm i.d. × 20 mm sealed glass capillary. The relative standard deviation for the peak intensity (mol %) resulting from ten replicate measurements of poly(butylene terephthalate) is approximately 3%. This method requires a small amount of sample (ca. 0.1 mg) and provides simple chromatograms, greater structural information, good reproducibility, and rapid reaction (0.5–15 min) without chemical treatment. A brief overview of applications to the characterization of some condensation polymers such as aromatic polyester, polycarbonate, and aliphatic and aromatic polyamide is also described.     

The forces and couples acting on two nearly touching spheres in low-Reynolds-number flow

When two unequal spheres are very close, the low-Reynolds-number flow in the narrow gap between them can be analysed using lubrication approximations, and asymptotic formulae for the forces and couples acting on the spheres deduced. The expressions for the forces and couples have previously been regarded as independent, but it is shown here that they are linked by simple physical considerations. The new formulae can be used to improve the accuracy of companion calculations which apply to cases in which the spheres are not close.

---

Zusammenfassung Es wird die Strömung bei kleinen Reynoldszahlen untersucht in einem Spalt zwischen zwei ungleichen Kugeln, die sich nahezu berühren. Asymptotische Formeln für die Kräfte und Momente an den Kugeln werden hergeleitet. Es wird gezeigt daß die Ausdrücke für die Kräfte und Momente, die bis jetzt als unabhängig betrachtet wurden, tatsächlich durch einfache physikalische Betrachtungen verknüpft werden können. Die neuen Formeln können zur Verbesserung der Genauigkeit von Rechnungen für größere Kugelabstände benützt werden.

---

---

During this work, D. J. Jeffrey was supported by the Natural Environment Research Council of Great Britain.     

Ground states of theXY-model

Ground states of theX Y-model on infinite one-dimensional lattice, specified by the Hamiltonian $$---J\left[ {\sum {\left\{ {(1 + \gamma )\sigma _x^{(j)} \sigma _x^{(j)} + (1 - \gamma )\sigma _y^{(j)} \sigma _y^{(j + 1)} } \right\} + 2\lambda \sum {\sigma _z^{(j)} } } } \right]$$ with real parametersJ≠0,γ andλ, are all determined. The model has a unique ground state for |λ|≧1, as well as forγ=0, |λ|<1; it has two pure ground states (with a broken symmetry relative to the 180° rotation of all spins around thez-axis) for |λ|<1,γ≠0, except for the known Ising case ofλ=0, |λ|=1, for which there are two additional irreducible representations (soliton sectors) with infinitely many vectors giving rise to ground states. The ergodic property of ground states under the time evolution is proved for the uniqueness region of parameters, while it is shown to fail (even if the pure ground states are considered) in the case of non-uniqueness region of parameters.     

Polymerization of cyclohexene oxide with aluminum complex/silanol catalyst. VI. Oligomer and polymer effects

The activity of an aluminum complex/polysilanol polymerization catalyst was examined in order to confirm the dependence of catalytic activation on silanol chain length. Tris (acetylacetonato)–aluminum/silanol increased when silanols with an intramolecular hydrogen bond such as the trimer of diphenylsilanediol, polydiphenyl(4-vinylphenyl)silanol, and polymeric silanol of silicone were used. However, when tris(ethylacetoacetato)aluminum or tris(salicylaldehydato)aluminum was used, the product obtained from the reaction of a part of the aluminum complex with the polysilanols had to be considered in any explanation of the catalytic activation. The active catalyst with such aluminum complexes was obtained when the silanols that had intramolecular hydrogen bonds and gave the appropriate ratio of the reaction between the aluminum complex and silanol were used.     

A simple and efficient synthesis of 2-alkylazulenes

The annulation method based on 2H-cyclohepta[b]furan-2-ones was applied for the synthesis of 2-alkylazulenes; 2-R-azulene (R = Et, i-Pr, n-Pr, i-Bu). Tropolone p-toluenesulfonate was used as a starting compound. By the two step synthesis, 1-carboxylic-3-cyanoazulene derivatives were obtained. Treatment of 1-carboxylic-3-cyanoazulene derivatives with aq H₂SO₄ resulted in decarboxylation and elimination of cyano group to give 2-alkylazulenes in good yields.     

Photocatalytic degradation of adenosine triphosphate in an aqueous suspension of TiO<Subscript>2</Subscript>: a HPLC and <Superscript>1</Superscript>H-NMR study

Photocatalytic degradation process of ATP was followed by HPLC and ¹H-NMR measurements. Adenine was one of the major products when the aqueous ATP sample with TiO₂ dispersion was irradiated by UV light (λ = 365 nm) for 90 min. The ¹H-NMR spectra indicated the presence of another product (Z), which likely came from the ribose moiety in ATP. Photocatalytic generation of OH^˙ radicals on TiO₂ surface was concluded to be responsible for degrading ATP. A working hypothesis of the reaction process was proposed to account for the reaction products.     

Reactions of a 2-picolyl-bridged palladium(ii) complex with some pyrazole derivatives

A 2-picolyl-bridged dinuclear complex, [Pd(2-picolyl)Cl(PPh₃)₂] (I) reacted with alkali metal salts of poly(1-pyrazolyl)borates, Na(BPz₄) (Pz = 1-pyrazolyl), Na(HBPz₃),and K(H₂BPz₂) to afford the complexes, [Pd(2-picolyl)(BPz₄)₂] (II), [Pd(2-picolyl)(HBPz₃)(PPh₃)] (III), and [Pd(2-picolyl)(H₂BPz₂)₂] (V), respectively. Complexes II and V retained the 2-picolyl bridge, whereas III was mononuclear without the bridge. Complex I was treated with hydrated silver perchlorate in the presence of tris(1-pyrazolyl)methane to give [Pd(2-picolyl)(OH₂)(PPh₃)₂](ClO₄)₂ (VI) without incorporating the neutral ligand.