离子液体在两相催化中的研究进展和应用前景

介绍了近年来离子液体用于液液两相催化加氢、氧化、Heck反应、氢酯化和羰化反应的研究进展,特别是结合离子液体在高碳烯烃氢甲酰化和低碳烯烃齐聚中试成果和已经实现工业应用的实例,从绿色化工的角度对其在化学工业中的应用前景进行了评述。     

离子液体催化脱除重整芳烃中微量烯烃

以室温离子液体作为催化剂,考察了间歇反应中离子液体用量和反应时间等因素对脱除芳烃中微量烯烃的影响,并通过连续反应考察了离子液体的寿命.结果表明,在室温,离子液体用量5%,反应10 min的条件下,[bmim]Br-AlCl2离子液体具有优良的催化性能,芳烃中微量烯烃脱除率达到98%以上.离子液体脱除烯烃催化反应机理是烷基化反应.     

［Emim］HSO4-AlCl3催化1-丁烯齐聚

制备Brnsted-Lewis双酸性离子液体催化剂［Emim］HSO4-AlCl3,并用于催化1-丁烯齐聚反应,考察催化剂用量、反应压力、反应温度和反应时间对1-丁烯齐聚产物选择性的影响。结果表明,强酸性离子液体催化1-丁烯齐聚反应得到的产物主要为四聚体。在n(AlCl₃)∶n(［Emim］HSO₄)=1∶1、催化剂用量2.5 g、反应温度30 ℃、反应压力0.08 MPa和反应时间1.0 h条件下进行齐聚反应,产物选择性和反应体系的稳定性较理想。     

离子液体/有机两相催化应用研究进展

作者就近年来离子液体/有机两相催化在加氢、氢甲酰化、齐聚、Heck反应和羰基化反应中的研究进展进行了综述,重点介绍了基于氟硼酸根(BF4-)或氟磷酸根(PF6 -)的咪唑类离子液体在均相催化反应中的应用,并对离子液体/有机两相催化工业应用的前景进行了探讨.     

α-烯烃齐聚制PAO催化剂的研究进展

综述了近年来α-烯烃齐聚合成PAO(聚α-烯烃润滑油基础油)的催化剂的研究进展。介绍了AlCl3、BF3、Ziegler-Natta催化体系以及近年来研究比较热门的离子液体及茂金属等几种类型的催化剂,评价了各种催化剂的优缺点,并且展望了烯烃齐聚反应催化剂的发展方向。     

羰基合成高碳醇工艺研究进展

综述了对液/液两相催化高碳烯烃氢甲酰化制备高碳醇的研究进展,针对经典的水/有机两相体系不能用于催化高碳烯烃氢甲酰化的问题,全面介绍了适用于水/有机两相体系中高碳烯烃氢甲酰化的温控相转移催化法等6种改进方法。同时对氟两相、离子液体两相、超临界流体等非水液/液两相体系中的高碳烯烃氢甲酰化作了系统阐述,并对它们的应用前景进行了评价。     

两相体系内PNP/Cr(Ⅲ)/MAO催化乙烯齐聚

通过1-n-丁基-3-甲基咪唑六氟磷酸盐离子液体([BMIM][PF6])/环己烷构建了液/液两相体系。研究了两相体系内反应温度、Al/Cr摩尔比、离子液体浓度等因素对异丙基双膦胺配体(PNP)/Cr(Ⅲ)/甲基铝氧烷(MAO)催化乙烯齐聚性能的影响。研究结果表明:与均相催化体系相比,两相体系内PNP/Cr(Ⅲ)/MAO催化乙烯由四聚变为三聚,61-C=的选择性最高达到97.40%。齐聚产物存在于有机溶剂相,催化剂溶解在离子液体相,便于产物与催化剂的分离及催化剂的循环使用。     

离子液体[EMIm]Br-FeCl_3催化1-丁烯齐聚反应

制备了离子液体[EMIm]Br-FeCl_3,并用于催化1-丁烯齐聚反应,考察了不同反应条件对其催化性能的影响,即对1-丁烯齐聚产物的组分及分布的影响。结果表明,1-丁烯齐聚产物随离子液体的构成和反应条件的变化而变化,其中[EMIm]Br与FeCl_3的物质的量比对产物选择性的影响较为显著。常压下,FeCl_3与[EMIm]Br物质的量比小、温度低和反应时间短有利于提高二聚物的选择性,六聚物减少。在离子液体{n(FeCl_3):n[EMIm]Br=1:1}用量0.01 mol、0.1 MPa时,升高温度和延长时间均会使三聚物、四聚物和五聚物的选择性增加。     

新型离子液体催化1-癸烯齐聚反应研究

选择盐酸-三氯化铝1-乙基-3-甲基咪唑溴盐([Emim]Br-A1Cl3-HCl)为离子液体催化剂,用于催化1-癸烯齐聚。研究了阴阳离子物质的量比和共催化剂用量以及聚合反应条件,如反应温度、催化剂用量、反应时间等对反应结果的影响,实验结果表明较佳的工艺条件为:阴阳离子物质的量比为3∶1,共催化剂用量0.09 mL,反应温度为120℃、m(催化剂)∶m(1-癸烯)=5∶100、反应时间3 h。在常压下,1-癸烯齐聚产物的转化率达到80%以上,并且符合聚α-烯烃(PAO)性能要求。     

离子液体催化1-丁烯齐聚反应

用AlCl3、FeCl3与溴化1-烷基-3-甲基咪唑盐([Rmim]Br)合成酸性离子液体,用于催化1-丁烯齐聚反应,考察反应温度、催化剂用量、反应时间、反应压力及催化剂阴阳离子物质的量比对齐聚产物选择性的影响.结果表明,以[C4mim]Br-FeCl3为催化体系效果较佳.在室温、催化剂用量2.0 g、反应时间2 h、...     

佛山市顺德新城区降水中污染物的监测和分析

为掌握佛山市顺德新城区降水中污染物的情况,2015年7月至8月,文章作者分别在雨天进行了降水取样,对降水中的pH、电导率、常见阴离子(F-、Cl~-、NO_3~(2-)、SO_4~(2-))及部分重金属(铅和镉)进行监测分析。选择有相关数据的珠江三角洲和石家庄、厦门等地的降水中污染物的情况进行对比。结果表明,顺德新城区降水中的p H和部分阴离子浓度优于珠江三角洲平均值,酸雨类型属于硫酸和硝酸混合型;其水体洁净程度略差于石家庄;铅和镉的浓度也高于厦门,甚至部分超出了人体能直接接触的安全范围。     

Metabolism of trideuterated iso-lignoceric acid in rats in Vivo and in human fibroblasts in culture

Saturated very long chain fatty acids (fatty acids with greater than 22 carbon atoms; VLCFA) accumulate in peroxisomal disorders, but there is little information on their turnover in patients. To determine the suitability of using stable isotope-labeled VLCFA in patients with these disorders, the metabolism of 22-methyl[23,23,23-²H₃]tricosanoic (iso-lignoceric) acid was studied in rats in vivo and in human skin fibroblasts in culture. The deuterated iso-VLCFA was degraded to the corresponding 16- and 18-carbon iso-fatty acids by rats in vivo and by normal human skin fibroblasts in culture, but there was little or no degradation in peroxisome-deficient (Zellweger’s syndrome) fibroblasts, indicating that its oxidation was peroxisomal. Neither the 14-, 20-, and 22-carbon iso-fatty acids nor the corresponding odd-chain metabolites could be detected. In the rat, the organ containing most of the iso-lignoceric acid, and its breakdown products, was the liver, whereas negligible amounts were detected in the brain, suggesting that little of the fatty acid crossed the blood-brain barrier. Our data indicate that VLCFA labeled with deuterium at the ω-position of the carbon chain are suitable derivatives for the in vivo investigation of patients with defects in peroxisomal β-oxidation because they are metabolized by the same pathways as the corresponding n-VLCFA. Moreover, as iso-VLCFA and their β-oxidation products are readily separated from the corresponding n-fatty acids by normal chromatographic procedures, the turnover of VLCFA can be more precisely measured. A preliminary report of part of this work (Reference 18) was presented at the 5th International Symposium on the Synthesis and Applications of Isotopes and Isotopically Labelled Compounds, Strasbourg, France, June 20–24, 1994.     

高效液相色谱法分析化妆品中微量成分的研究进展

综述了高效液相色谱法在化妆品中防腐剂、防晒剂中紫外线吸收剂以及性激素的检测等几个方面的应用;同时,介绍了分析所用的色谱柱、流动相、使用的检测手段以及样品的提取方法;最后针对目前存在的问题,提出了高效液相色谱用于化妆品中微量成分分析的研究方向和发展前景。     

Denitrification in shallow groundwater in a coastal agricultural area in Japan

In a coastal agricultural area in the central part of Japan (Shizuoka), we found decreasing nitrate concentration with depth in a shallow groundwater, where the depth to water table varied between 0.6 and 1.2 m below ground surface. High nitrate concentrations (5–29 mg N L^–1) were often observed in the upper layer (0–2 m) of the groundwater, but the concentration decreased to less than 1 mg N L^–1 in the deeper layer. Ammonium was scarcely detected, and the concentration of dissolved oxygen was usually low (< 1 mgO₂ L^–1) in the groundwater. Nitrate in the groundwater often had very heavy nitrogen stable isotope ratios (>20{}). There was a negative relationship between nitrogen stable isotope ratio of nitrate and its concentration. When nitrate was injected into the groundwater with acetylene and bromide (a conservative tracer), nitrate concentration decreased to 20% of the initial level within 5 days, accompanied by the increase in nitrite and nitrous oxide concentration and a little change in bromide concentration. These results indicate that microbial denitrification plays a potential role in the decrease of nitrate in shallow groundwater at the study site.     

我国硝酸工业生产技术新进展

系统叙述了我国硝酸工业2000-2007年生产现状及主要技术成果,尤其指出了国产"四合一"机组的成功投运,使我国硝酸国产化装置取得较大的进步,表现在吨酸的铂耗、氨耗和能耗等方面接近国外引进装置水平,同时介绍了国外双加压法硝酸生产技术的进展.我国已成为硝酸生产大国,仍需以先进的技术改造和发展我国硝酸工业,确保我国硝酸工业健康有序地发展,加快从硝酸生产大国向强国迈进的步伐.