The Chemistry of Water Treatment Processes Involving Ozone,Hydrogen Peroxide and Ultraviolet Radiation

Advanced oxidation processes are defined as those which involve the generation of hydroxyl radicals in sufficient quantity to affect water purification. The theoretical and (practical yield of OH from O₃ at high pH, 0₃/H₂0₂, O₃/UV and H₂O₂/UV systems is reviewed. New data is presented which illustrates the importance of direct photolysis in the O₃/UV process, the effect of the H₂0₂:0₃ ratio in the O₃/H₂O₂ process, and the impact of the low extinction coefficient of H₂O₂ in the H₂0₂/UV process.     

Laboratory study of soil acidification and leaching of nutrients from a soil amended with various surface-incorporated acidifying agents

Granular S, finely-ground S, iron sulphate and aluminium sulphate were added at two rates to the surface (0–6 cm) of a soil and acidification and leaching of nutrients were measured over 12 months in a laboratory study. Iron and aluminium sulphate both rapidly lowered soil pH in the top 0–6 cm of the soil. There was little difference in soil pH after 3 and 12 months reaction of these two amendments. In contrast, for granular S and finely-ground S there were clear decreases in soil pH between 3 and 12 months reaction with the soil. Finely-ground S was oxidized in the soil faster than granular S and therefore had a more acidifying effect. The top 0–6 cm of the soil was acidified by all the agents used but the deeper soil was less affected. The only treatments which lowered the pH of the 12–18 cm layer below pH 6 were the high rates of iron and aluminium sulphate. Soil acidification resulted in a decrease in exchangeable Ca, Mg and K, an increase in exchangeable Al and a decrease in effective CEC in the acidified soil layers.At both levels of addition, total ionic strength of percolates from the soil followed the order: aluminium sulphate = iron sulphate > finely gound S > granular S > control and was higher at the higher rate of addition. The pH values of percolates followed the order: control > granular S > finely ground S > iron sulphate = aluminium sulphate and were lower at the higher rate of addition. For the amended soils there was a very close relationship between the pattern and total amounts of SO ₄ ^2- and Ca²⁺ leached.It was concluded that granular S is not an effective acidifying agent since it is oxidized very slowly in the soil and that acidfying agents should be incorporated to the depth that acidification is required.     

Ni-W2C催化葡萄糖氢解制备低碳二元醇反应机理研究

采用HPLC、LC-MS、GC-MS等分析手段对不同工艺条件下Ni/W₂C催化葡萄糖加氢转化的中间产物及终产物进行定性定量分析，研究了葡萄糖加氢转化过程的反应机制和历程。研究发现：葡萄糖加氢转化过程中同时平行发生了加氢、异构和逆向羟醛缩合（氢解）三类反应；葡萄糖发生加氢反应能够得到六元醇且其不会再进一步转化，发生逆向羟醛缩合反应主要生成乙二醇（C₂产物），发生异构反应则可生成果糖，其进行逆向羟醛缩合的产物则为1,2-丙二醇和甘油（C₃产物）；高浓度葡萄糖条件下，其异构产物果糖发生脱水反应生成的5-HMF浓度过高发生聚合，进而导致结焦。根据葡萄糖加氢转化的反应网络，提出了调控反应过程中C₂产物和C₃产物分布的策略，并通过增加催化剂用量来加快果糖脱水的竞争反应速率(加氢、氢解)，进而实现了高浓度（10%，质量分数）葡萄糖的加氢转化。此外，葡萄糖加氢转化过程中存在明显的浓度效应，反应物浓度越低，越有利于发生逆向羟醛缩合反应，反之则有利于发生加氢反应。     

电力绝缘用六氟化硫替代物的过去、现在和未来

本文综述了电力绝缘用SF6替代物的开发方法、发展现状和未来趋势。其开发方法包括替代物的设计与确认（物性、安全性评价、环境影响的评价等）、合成、产业化等内容。目前，开发出的SF6替代物包括SF6混合气体、饱和卤代烃、氢氟烯烃、全氟酮和全氟腈，其中七氟异丁腈的绝缘性能优异，是SF6最佳的替代物。同时文中综述了现有七氟异丁腈的合成路线，其中以碳酰氟和六氟丙烯为起始原料催化反应合成七氟异丁腈的路线，具有高效、绿色、环保的优点。以过去发展历程和现在发现现状为基础，展望了SF6替代物的未来发展趋势，提出今后的研究重点在于全面开发七氟异丁腈的应用配套设备，下一代SF6替代物及其绿色、高效的产业化路线。     

头孢匹罗的合成

丙炔胺和环戊酮在无水乙醇中回流反应5 h生成2,3-环戊烯并吡啶,收率55%。7-氨基头孢烷酸和2-甲氧亚氨基-2-(2-氨基-4-噻唑基)-(z)-硫代乙酸苯胼噻唑酯(AE活性酯)发生酰化反应生成头孢噻肟酸,收率90%。在三甲基碘硅烷作用下,头孢噻肟酸与2,3-环戊烯并吡啶反应,生成头孢匹罗,收率65%1。H NMR对产物及中间体进行了鉴定。     

2-氨基嘧啶合成工艺的研究

介绍了2氨基嘧啶的制备方法,并通过正交法研究了多种因素对总收率的影响,得到了较佳的工艺条件。实验结果表明,丙二酸二乙酯与胍物质量的比为1.1∶1,三氯氧磷与胍物质量的比为1.2∶1,锌粉与胍物质量的比0.23∶1,三次回流反应总时间为15h,总收率最高为76.2%。     

Oxidative dehydrogenation of ethane over Co–BaCO3 catalysts using CO2 as oxidant: effects of Co promoter

Co–BaCO₃ catalysts exhibited high catalytic performance for oxidative dehydrogenation of ethane (ODE) using CO₂ as oxidant. The maximal formation rate of C₂H₄ was 0.264 mmol · min⁻¹ · (g · cat.)⁻¹ (48.0% C₂H₆ conversion, 92.2% C₂H₄ selectivity, 44.3% C₂H₄ yield) on 7 wt% Co–BaCO₃ catalyst at 650 °C and 6000 ml. (g · cat.)⁻¹. h⁻¹. Co–BaCO₃ catalysts were comparatively characterized by XRF, N₂ isotherm adsorption-desorption, XRD, H₂-TPR and LRs. It was found that Co⁴⁺–O species were active sites on these catalysts in ODE with CO₂. The redox cycle of Co–O species played an important role on the catalytic performance of Co–BaCO₃ catalysts. On the other hand, the co-operation of BaCO₃ and BaCoO₃ was considered to be one of possible reasons for the high catalytic activity of these catalysts.     

Photostabilization of cationic UV-cured coatings in the presence of nanoTiO2

The effect of TiO₂ nanoparticles for sun-weathering protection of UV-cured coatings is investigated. TiO₂ is either introduced in the form of nanoparticles in the photocurable formulations or generated in situ via sol–gel process. Cured films containing comparable amounts of TiO₂ were weathered for 800 h under UV irradiation and compared with free-TiO₂ coating. The TiO₂ presence induces a clear lower mass loss decrease during weathering as well as a lower gel content decrease. The TiO₂ screen effect is also confirmed by a lower alkyl-band reduction monitored by FT-IR during weathering. The TiO₂ generated in situ via sol–gel gives rise to transparent coatings without interfering with photopolymerization process and therefore without compromising UV-cured film properties.     

高收率合成DADE的新方法

在比较DADE的3条文献合成路线基础上，研究了以2-甲基-4，6-嘧啶二酮为母体用硝硫混酸硝化生成中间体2-(二硝基亚甲基)-5，5-二硝基-2H-嘧啶-4，6-二酮、中间体水解合成DADE的方法。DADE总收率达到83％以上，用IR、MS、NMR及元素分析鉴定了其结构。     

Alarm pheromone system of leaf-footed bugLeptoglossus zonatus (Heteroptera: Coreidae)

The alarm pheromone system ofLeptoglossus zonatus (Dallas) adults was shown to be composed of hexyl acetate, hexanol, hexanal, and hexanoic acid. Single components tested in the field elicited dispersive behavior of over 70% of adults. 2-(E)-Hexenal, found in the secretion of nymphs, but not in the exudates of adults, was also active against adults. In addition, first-instar nymphs responded to the four components of the alarm pheromone of adults as well as to 2-(E)-hexenal, a component of their own alarm pheromone system. Adults and nymphs possess different alarm pheromone systems, which are not specific to their own life stage. That hemipteran alarm pheromone systems are not species-specific was supported by the fact that both adult and nymphL. zonatus responded to butanoic acid, an alarm pheromone of Alydidae, which was not found in this Coreidae species.