The two-phase structure of segmented block copoly(ether ester)

The annealing induced morphological changes in isotropic block copoly(etherester)s are investigated by small angle X-ray scattering methods. The observed results are consistent with a lamellar model which is comprised of a crystalline core of thickness 35 to 45 Å, a diffuse boundary zone of width 9 Å, and an amorphous layer which is varying strongly in thickness. The enhanced crystallinity of the samples annealed at higher temperatures is mainly due the lateral growth of the lamellae; the long period increases by not more than 20%. The scattering power of the samples is explained by means of an equivalent two-phase model in which the crystalline phase has the same structure as theα-form of poly(butylene terephthalate), whereas the amorphous phase is a mixture of the uncrystallized ester segments and the ether segments. The crystallinity determined from the scattering power is very much higher than that determined from thermoanalytical investigations.     

The physicochemical properties of aqueous mixtures of cationic-anionic surfactants: I. The effect of chain length symmetry

The solution behaviors of equimolar mixtures of cationic-anionic surfactants have been studied by means of the dynamic light scattering technique and surface tension measurements. The surface activity and the micellization properties are different for systems of different hydrophobic chain length symmetry. For systems of lower symmetry (e.g., C₆H₁₃NC₅H₅Br-C₁₂H₂₅SO₄Na mixture), the surface tension at cmc (γ_cmc) is rather high (above 30 mN m⁻¹) and the mixtures form genuinely homogeneous micellar solutions above the cmc. For the systems of high symmetry (e.g., C₈H₁₇NC₅H₅Br-C₈H₁₇SO₄Na mixture), γ_cmc is very low (about 24 mN m⁻¹, near the value of pure hydrocarbon) and in the apparently homogeneous and clear mixtures slightly above cmc, the aggregates grow slowly and eventually form small droplets; as the concentration is further increased, all these solutions become turbid. We have proposed a new concept of conformation energy of aggregates to account for all these phenomena. Mixtures of octyltriethylammonium bromide and sodium octylsulfate form clear homogeneous micellar solutions in keeping with predictions based upon this concept.     

Indole derivatives

A method for the introduction of a 3-indolyl group in compounds with an active methylene group was developed. The corresponding 3-indolyl diketones were obtained by condensation of 1-acetyl-3-indolinone with dimedone, 4-hydroxycoumarin, 1,2-diphenyl-3,5-pyrazolinedione, and barbituric and thiobarbituric acids and subsequent alkaline hydrolysis of the condensation products. The existence of cyclic six-membered 3-indolyl diketones in the enol form and of cyclic five-membered 3-indoly diketones in the keto form was shown by IR and UV spectroscopy. Depending on the conditions, (1-acetyl-3-indolyl)cyanoacetamide, 1,3-bis(1-acetyl-3-indolyl)-1,3,3-tricyano-2-amino-1-propene, and 1-acetyl-3-indolylmalononitrile are obtained in the condensation of 1-acetyl-3-indolinone with malononitrile. 1-Acetyl-3-indolylmalononitrile exists in equilibrium with the keteneimine form and in protic solvents is converted to 3-cyano-8-acetylpyrrolo[2,3-b]indole by intramolecular cyclization.See [1] for communication CX.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 360–368, March, 1977.     

Hydroxylamine derivatives

The condensation of urethane and ethyl acetohydroximate with 2-chloromethyl-1-methylbenzimidazole has given, respectively, N-ethoxycarbonyl-O-(1-methylbenzimidazol-2-ylmethyl)hydroxylamine and ethyl N-(1-methylbenzimidazol-2-ylmethoxy)acetimidate. Acid hydrolysis of the latter has given O-(1-methylbenzimidazol-2-ylmethyl)hydroxylamine. The reactions of its derivatives with HCl have been studied, and it has been shown that 1-methylbenzimidazole-2-aldehyde O-(1-methylbenzimidazole-2-methyl)oxime is formed. The structure of the latter has been shown by an analysis of its PMR spectra.For part II, see ¦1¦.     

Adsorption of 1,10-phenanthroline within a dodecanethiol monolayer: an approach to a switchable electrode surface

A simple method was used to prepare a "switchable" electrode surface by using self-assembled monolayers of dodecanethiol on a gold electrode. The dodecane-modified electrode was electrochemically inactive until the monolayer was soaked in solutions of 1,10-phenanthroline or 2,2'-bipyridine. The electroactive form of the electrode could be reverted back to the nonelectroactive form by rinsing the electrode. Surface IR results showed that both dodecanethiol and 1,10-phenanthroline exist in the mixed monolayer.     

Synthesis of pyrimidine betaines with phosphonium and cycloammonium cations

Previously undescribed pyrimidine betaines with cycloammonium and triphenylphosphonium cations were obtained. A study of the UV, IR, PMR, and mass spectra made it possible to draw a conclusion regarding the noncyclic structure of betaines stabilized by an intramolecular donor-acceptor interaction of the charge-transfer complex (CTC) type.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1687–1690, December, 1978.     

3, 3, 3-Trifluoropropyl(methyl)cyclosiloxanes

The influence of the number of 3, 3, 3-trifluoropropyl(methyl)siloxane links (Φ/Φ) in the cyclotetrasiloxanes Φ_mD_4-m, where D represents the dimethylsiloxane link and m=0–4, on the rearrangement of these compounds in acetone solution under the action of sodium siloxanolate has been studied. The rearrangement takes place with the formation of a linear polysiloxane the degradation of which yields, in addition to the initial ring, cyclosiloxanes with a different structure. The rate of rearrangement of Φ_mD_4-m and of the formation of a linear polysiloxane rises with an increase in m from 0 to 3. The equilibrium concentration of the linear polysiloxane formed from Φ_mD_4-m is inversely proportional to m. Results have been obtained on the kinetics of the formation of the cyclosiloxanes Φ_mD_n, where m=0–5, n=0–5, and m+n=3–6, in the rearrangement of the rings ΦD₃, Φ₂D₂, Φ₃D, and Φ₄. The reactivity of the siloxane links rises in the sequence ～ (CH₃)₂Si-O-Si(CH₃)₂ ～<～ (CF₃CH₂CH₂)-(CH₃) Si-O-Si(CH₃)₂ ～<(CF₃CH₂CH₂) (CH₃)Si-O-Si(CH₃) (CH₂CH₂CF₃) ～. Because of the negative inductive effect transferred through the siloxane links, the 3, 3, 3-trifluoropropyl groups strongly activate the siloxane ring with respect to nucleophiiic reagents.     

Gas-Chromatographic Determination of Butanol and Butyl Acrylate in Aqueous Solutions with the Use of Headspace Analysis

A procedure has been developed for the determination of the concentration of butanol and butyl acrylate in aqueous solutions in the range of 0.5–20 MPC. The procedure is based on static headspace gas-chromatographic analysis on a column filled with the Chromaton N-AW-HMDS sorbent containing 15 wt % of polyethylene glycol adipate with detection by a flame-ionization detector.