Crystallization of poly(N-methyldodecano-12-lactam) in blends with poly(styrene-stat-acrylic acid)

Crystallization behaviour of blends of poly(N-methyldodecano-12-lactam) (PMDL) with statistical copolymer poly(styrene-stat-acrylic acid) (PSAA) has been studied by the DSC and WAXD methods. The blend films prepared from dioxane solutions were crystallized at laboratory temperature for five days. Approximate crystallinities of as-prepared neat lower- PMDL 5 and higher-molecular weight PMDL 45 were 28% and 19%, respectively. With increasing PSAA content in the blends the crystallinities decreased sharply. The melting point of the primary crystalline structure of PMDL showed a decreasing dependence on PSAA content in the blends, confirming miscibility of the PMDL-PSAA pair. Recrystallization was strongly suppressed in the blends. The lower-melting endotherm appearing at about 10-15 °C above the crystallization temperature was attributed to melting to less perfect structures formed during secondary crystallization. In neat PMDL, the extent of secondary crystallization was approximately 5-10%. In the blends containing 20% PSAA approximate relative proportion of secondary crystallites on total crystallinity was 40% and 60% for the blends with PMDL 5 and PMDL 45, respectively. WAXD measurements did not reveal any change in crystal modification on blending. Increased T_g in blends of flexible PMDL cannot play a significant role in suppression of primary in favour of secondary crystallization. This was attributed to low mobility of PMDL chains due to dilution effect and specific interactions with the amorphous copolymer component, and, in case of the higher-molecular-weight PMDL, a greater involvement of entanglements. Higher T_g of blends was involved in retardation of non-isothermal crystallization on cooling and subsequent cold crystallization.     

Synthetic studies on 3-arylquinazolin-4-ones: intramolecular nucleophilic aromatic substitution reaction of 2-carboxamido-3-arylquinazolin-4-ones and its application to the synthesis of secondary aryl amines

The general synthesis and a novel intramolecular nucleophilic aromatic substitution (S_NAr) reaction of 2-carboxamido-3-arylquinazolin-4-ones, a potentially useful scaffold in the field of medicinal chemistry, are described. The synthetic utility of the S_NAr reaction as a tool for the synthesis of secondary aryl amines, including diaryl amines, is also demonstrated.     

次级键与晶体中锑(III)螯合物配位多面体研究

考虑立体活性孤对电子附近次级键配位原子的贡献, 对文献报道的三十个氨基多羧酸锑(III)螯合物的晶体结构中配位多面体描述进行了全面的修正. 配位多面体的几何构型指定采用了单位球内截多面体的两面角判据及其相关的ANVPDA程序. 所有配位多面体几何构型的修正均得到了键价计算的有力支持.     

次级键与晶体中锑(III)螯合物配位多面体研究

考虑立体活性孤对电子附近次级键配位原子的贡献,对文献报道的三十个氨基多羧酸锑(III)螯合物的晶体结构中配位多面体描述进行了全面的修正.配位多面体的几何构型指定采用了单位球内截多面体的两面角判据及其相关的ANVPDA程序.所有配位多面体几何构型的修正均得到了键价计算的有力支持.     

Continuous chemiluminescence determination of formaldehyde in air based on Trautz-Schorigin reaction

A new continuous method for the determination of formaldehyde in air is described. A cylindrical wet effluent diffusion denuder is used for the collection of formaldehyde from air into a thin film of absorption liquid (distilled-deionized water). Formaldehyde in the denuder concentrate is on-line detected employing a chemiluminescence flow method based on a reaction of formaldehyde and gallic acid with hydrogen peroxide in an alkaline solution. The collection efficiency of formaldehyde is quantitative at the air flow rate of 0.5 L min⁻¹ (absorption liquid flow rate of 336 μL min⁻¹). The limit of detection (S/N = 3) is 0.60 μg m⁻³ HCHO (0.49 ppb). The calibration graph is linear up to 300 μg m⁻³ HCHO (244 ppb). The relative standard deviations of chemiluminescence method for 1 × 10⁻⁶ and 5 × 10⁻⁶ M HCHO are 2.87% and 1.49%, respectively. Acetaldehyde interferes negligible, other compounds do not interfere. The method was employed for formaldehyde measurement in ambient air. The comparison measurement illustrates the good agreement of results obtained by proposed method with those obtained by reference fluorimetric method.     

Investigations of regio- and stereoselectivities in the synthesis of cytotoxic isoxazolidines through 1,3-dipolar cycloadditions of nitrones to dipolarophiles bearing an allylic oxygen

Regio- and stereoselectivities in cycloadditions of nitrones to dipolarophiles bearing an allylic oxygen, which furnishes substituted-isoxazolidine analogs of the furanose ring of nucleosides, have been investigated. Although the obtained regioselectivities are anticipated, a rationalization of the preferred formation of endo-cycloadducts necessitates the involvement of an allylic oxygen in secondary interaction. The obtained isoxazolidines display cytotoxic activities against a number of human cancer cell lines.     

化妆品车间空气消毒方法效果比较

评价几种消毒方法对化妆品车间空气的消毒效果。分别使用紫外线照射消毒法、甲醛蒸熏消毒法、戊二醛消毒液气溶胶雾化消毒法、臭氧气体发生器消毒法4种方法进行消毒,然后用平皿沉降法进行采样评价分析,试验结果表明,戊二醛消毒法和臭氧消毒法可以代替紫外线消毒法和甲醛消毒法进行化妆品车间空气常规消毒。     

Sulfonamides as ionophores for ion-selective electrodes. IV. New secondary sulfonamide podands and cryptands

New compounds — podands and cryptands with two secondary sulfonamide groups —have been synthesized and are described. They were tested as ionophores for guanidinium ions in PVC-membrane electrodes with bis (2-ethylhexyl)sebacate (DOS) as plasticizer.