聚丙烯无卤阻燃剂研究进展

介绍了金属氢氧化物、磷系阻燃剂、膨胀型阻燃剂、有机硅系阻燃剂和纳米阻燃剂等无卤阻燃剂在聚丙烯中的应用情况。指出了研制和开发高效、无毒、无烟、无环境污染、热稳定性好、多功能和新型复合“绿色”阻燃剂,将成为以后聚丙烯无卤阻燃剂的发展趋势。     

Chlorinated Natural Products and Related Halogenases

Halogenated compounds are well‐known for their diverse bioactivities and wide applications in pharmaceutical industry, chemical engineering and other fields. Novel halometabolites isolated from nature inspire scientists to synthesize these “chance compounds”, which were, however, usually hampered by the extreme catalytic conditions and severe selectivity challenges. In the past several decades, enzymatic reactions have been brought into attention for their efficiency, selectivity, and mild reaction conditions. Synthetic biology which is in compliance with the laws of nature to a large extent shed light on the rational biosynthesis of halogenated compounds. This article summarizes several representative categories of halogenated natural products and halogenases to seek clues to the relationship between the structures and halogenase mechanisms. Some types of halogenase convert the basic building blocks to diverse early intermediates during natural product biosynthetic processes, while others are involved in the late tailoring steps to afford the final structures of halogenated molecules. The broad substrate specificity and strong regioselectivity exhibited in some halogenases are irreplaceable advantages for biosynthesis. In addition, tremendous efforts and encouraging results enable us to engineer the enzymes or techniques to synthesize “unnatural” halogenated natural products. More reaction mechanisms and structural data are expected to be revealed exponentially in this rapid growing realm.     

Phenazine Antibiotic-Inspired Discovery of Bacterial Biofilm-Eradicating Agents

Bacterial biofilms are surface-attached communities of slow-growing and non-replicating persister cells that demonstrate high levels of antibiotic tolerance. Biofilms occur in nearly 80 % of infections and present unique challenges to our current arsenal of antibiotic therapies, all of which were initially discovered for their abilities to target rapidly dividing, free-floating planktonic bacteria. Bacterial biofilms are credited as the underlying cause of chronic and recurring bacterial infections. Innovative approaches are required to identify new small molecules that operate through bacterial growth-independent mechanisms to effectively eradicate biofilms. One source of inspiration comes from within the lungs of young cystic fibrosis (CF) patients, who often endure persistent Staphylococcus aureus infections. As these CF patients age, Pseudomonas aeruginosa co-infects the lungs and utilizes phenazine antibiotics to eradicate the established S. aureus infection. Our group has taken a special interest in this microbial competition strategy and we are investigating the potential of phenazine antibiotic-inspired compounds and synthetic analogues thereof to eradicate persistent bacterial biofilms. To discover new biofilm-eradicating agents, we have established an interdisciplinary research program involving synthetic medicinal chemistry, microbiology and molecular biology. From these efforts, we have identified a series of halogenated phenazines (HPs) that potently eradicate bacterial biofilms, and future work aims to translate these preliminary findings into ground-breaking clinical advances for the treatment of persistent biofilm infections.     

The solubility of HCFC22, CFC114 and HFC152A in n-hexadecane

The solubilities of chlorodifluoromethane (HCFC22), 1, 2-dichlorotetrafluoroethane (CFC114) and 1,1-difluoroethane (HFC 152a) in n-hexadecane have been measured at temperatures between 303. 15 and 343. IS K and Henry's constants have been derived. The measurements were made with two different methods, a GLC method and an isochoric method. In general the results of the methods differ less than their combined margin of error, which is estimated to be less than 5% for the GLC method and less than 2% for the isochoric method.     

Allelochemical inhibition of recruitment in a sedimentary assemblage

Chemical signals affect recruitment of organisms in many habitats. Most of the described biogenic chemical moieties in marine environments elicit specific positive responses, for example, of predators to prey or of conspecific larvae to suitable habitats. However, organisms also release noxious chemicals that may elicit negative responses from neighboring members of the assemblage. Herein we measured the effect on recruitment of the release of such compounds (halogenated aromatics) into sediments. The common, sediment-dwelling, terebellid polychaeteThelepus crispus contains brominated aromatic metabolites and contaminates the sediments surrounding its tube with these compounds. Sediments so contaminated are actively rejected by recruitingNereis vexillosa (Nereidae: Polychaeta). Interestingly, many of these noxious biogenic compounds have low solubility in water and, therefore, potentially long residence times in sedimentary environments. The negative response of larvae to sediment contaminated with them is a novel, potentially common, and very important mechanism in which sediment-dwelling organisms release haloaromatic compounds and thus impose a recruitment filter on their community.     

Project Tocoen. The Fate of Selected Organic Compounds in the Environment. Part XXVIII. Levels of PAHs and Some Halogenated POPs in Ambient Air in Czech Republic

Abstract

Concentrations of polyaromatic hydrocarbons (PAHs), chlorinated pesticides, polychlorinated biphenyls, dibenzo-p-dioxins and dibenzo-p-furans (PCDDs/Fs) in ambient air in Ko?etice, a background locality in the South Bohemia, have been estimated in the period from July to December 1994. The 24-hours samples have been taken by the means of a high-volume sampler. Sample analysis involved Soxhlet extraction of polyurethane foam, extract preconcentration and chromatographic clean-up procedure followed by HPLC determination of PAHs with fluorescence detection, GC/ECD determination of chlorinated pollutants, and GC/MS determination of PCDDs/Fs. The results of this first detailed study undertaken in Czech Republic are compared with the data obtained by similar projects in industrial and/or urban areas in the Czech Republic and in rural or urban areas in other European countries.     

可见光催化降解水中卤代有机污染物的研究进展

卤代有机污染物（HOCs）在水环境中检出频率高达45%,由于其具有毒性大、持久性强和易累积等特点,该类污染物引发的环境问题已引起越来越多的关注。可见光催化技术具有高效太阳能利用率、强选择性及反应条件温和、处理费用低等优点,对于降解水中HOCs具有独特的处理优势,因此近年来被广泛研究。本文梳理了可见光催化降解水中HOCs的核心脱卤机制,包括氧化脱卤、还原脱卤和水解脱卤,在脱卤机制的基础上汇总了三大类主流催化剂的脱卤贡献率,主要包括金属基光催化剂、碳基光催化剂及其他新型光催化剂三类光催化材料。基于可见光作用下降解水中HOCs的应用案例分析,探讨了光催化反应过程中的主要影响因素是溶液pH、催化剂用量及反应温度等。可见光催化降解去除效率高是本技术的核心优势,但由于催化剂的成本高和选择性差导致了其无法大规模应用,未来可见光催化材料设计应向成本低廉、精准匹配污染物从而实现高选择性的方向改进。     

氯代吡啶化合物的研究应用与展望

介绍了吡啶氯化物分类、合成进展,分析了不同的合成路线之间的优缺点,并简介了其在医药、农药、香料、橡胶和染料方面的应用及预测。     

全卤制碱工艺探讨

介绍全卤制碱工艺的特点、流程及工艺改进方案。     

Routes to polymer-based photonics

The advances in polymer materials and technologies for telecom applications are reported. The polymers include new highly halogenated acrylates, which possess absorption losses less than 0.25 dB/cm and refractive indices ranging from 1.3 to 1.5 in the 1.5 μm wavelength region. The halogenated liquid monomers are highly intermixable, photocurable under UV exposure and exhibit high contrast in polymerization. The polymer technologies developed at the Institute on Laser and Information Technologies of the Russian Academy of Sciences (ILIT RAS) include: