均相烯烃氢甲酰化铑催化剂的最新研究进展

烯烃氢甲酰化反应(Hydroformylation),又称OXO合成,是指烯烃与合成气(CO和H2)在催化剂的作用下生成多一个碳原子的正构醛(n-alde-烯烃氢甲酰化反应最早是Roelen[1](1897~1993)于1938年在德国鲁尔化学公司从事费托合成中发现的.目前,该反应以每年800~900万吨的产量成为当今世界最重要的有机化工工艺[2],其产品遍及各种不同碳数的醛和醇,其中最主要的除由丙烯出发合成丁、辛醇外,还有以高碳烯烃为原料的C8-11增塑剂醇和C12-18的表面活性剂醇,被广泛用于增塑剂、织物添加剂、表面活性剂、药物中间体、溶剂和香料等精细化工领域[3,4].均相氢…     

大功率LED脉冲位置调制解调设计

脉冲位置调制是室内可见光通信的主要调制方式之一,它具有功率利用率高,频带利用率好,抗干扰性强的特点.为实现室内大功率白光LED照明通信,在分析PPM的原理基础上提出了一种改进的调制方式,给出了这种PPM符号的结构,并设计了大功率LED的驱动电路.其主要特点是由单片机直接输出帧同步信号加PPM信号,不设置保护时隙,其利用...     

非平衡态氧等离子体性质的实验研究

给出了寂静放电产生的非平衡态氧等离子体特性的实验研究结果,并对空气中及氧气中合成臭氧的特性进行了研究,得到了在纯氧放电时臭氧质量浓度Ｃ＝ １８．９ｍ ｇ ·Ｌ－ １、臭氧产率Ｑ＝１８００ｍ ｇ ·ｈ－ １、臭氧单能产率η＝ ７０ｇ ·（ｋＷ ·ｈ）－ １ 的实验结果,同时对影响Ｃ、Ｑ的因素也进行了研究。最后,就臭氧对造纸黑液的脱色、降粘及脱木素的作用进行了实验探讨     

Nd:LuVO_4晶体的拉曼光谱研究

采用不同的几何配置测量了Nd:LuVO4晶体的室温拉曼光谱,根据群论对称性分类计算了该晶体的红外和拉曼活性振动模并与实验结果做了比较,指认了测定的特征谱线。测量并分析了Nd:LuVO4晶体A1g全对称类的高温拉曼光谱,讨论了拉曼频移随温度变化的关系,认为晶体的热膨胀是引起拉曼频移变化的主要原因。     

Synthesis and property of a novel sulfonated poly(ether ether ketone) with high selectivity for direct methanol fuel cell applications

A novel membrane material based on random copolymer composed of poly(acrylonitrile-([3-(methacryloylamino)propyl]-dimethyl(3-sulfopropyl) ammonium hydroxide)) (PAN–MPDSAH) was synthesized by the water phase suspension polymerization. The zwitterionic PAN-based membranes were prepared through blending PAN and PAN–MPDSAH copolymer by a phase inversion method. The zwitterionic PAN-based membranes have higher hydrophilicity and wettability, and lower protein adsorption in comparison with the control PAN membrane. Ultrafiltration experiments revealed that membrane fouling, especially irreversible membrane fouling, for the zwitterionic PAN-based membranes is remarkably reduced due to the incorporation of zwitterionic PMPDSAH segments on the membrane surfaces. Moreover, the reversible membrane fouling during ultrafiltration process can be easily washed away by simple water cleaning. The zwitterionic PAN-based membranes can run for a long time and be reused without significant decrease of separation performance.     

固相萃取-高效液相色谱法同时测定食品塑料包装材料中9种光稳定剂

建立了同时测定食品塑料包装材料中9种紫外光稳定剂含量的高效液相色谱方法。样品用甲醇-乙酸乙酯混合溶剂超声提取,经固相萃取小柱净化后,以ZORBAX SB-C18柱(250 mm×4.6 mm, 5 μm)为分离色谱柱,甲醇和水为流动相,梯度洗脱,以310 nm为检测波长进行定性、定量分析。该方法前处理简单、易操作,9种紫外光稳定剂分离效果良好。9种紫外光稳定剂在0.2～10 mg/L范围内呈良好的线性关系,线性相关系数大于0.999;方法检出限为0.05～0.1 mg/L;实际样品中的加标回收率为70.2%～89.0%,相对标准偏差为0.4%～4.5%。该方法简单、准确,能够满足食品塑料包装材料中紫外光稳定剂的检测要求。     

Distance riemannienne,théorème de Rademacher et inégalité de transport sur le groupe des lacets

In this Note, we shall consider the Riemannian distance on loop groups, which will be identified to one introduced by Hino and Ramirez [M. Hino, J.A. Ramirez, Small-time Gaussian behavior of symmetric diffusion semigroups, Ann. Probab. 31 (2003) 1254–1295]. A transportation cost inequality is established. To cite this article: S. Fang, J. Shao, C. R. Acad. Sci. Paris, Ser. I 341 (2005).     

钛硅分子筛TS-1合成晶化气氛的影响

考察了不同晶化气氛(N2、H2、A ir、O2)对合成钛硅分子筛TS-1的影响,用XRD、IR和N2吸附/脱附对所合成的钛硅分子筛进行结构表征,发现在H2气氛下合成的TS-1结晶度最高,锐钛矿的含量最少;O2气氛下合成的TS-1中锐钛矿含量最高.以氯丙烯氧化为模型反应,考察了不同晶化气氛下合成的钛硅分子筛的催化活性和双氧水的利用效率.结果表明,在H2气氛下所合成的钛硅分子筛的双氧水的利用效率最高.     

嫁接Al改性MCM-41介孔分子筛催化合成双酚F

以十六烷基三甲基溴化铵和正硅酸乙酯为原料,合成纯硅MCM-41介孔分子筛。 再利用九水硝酸铝为改性剂来嫁接改性纯硅MCM-41介孔分子筛,NH3-TPD结果表明,嫁接后的AlMCM-41产生了中强酸。 用改性后不同n(Si)/n(Al)的AlMCM-41催化合成双酚F,在n（苯酚）/n（甲醛）=30、反应时间5 h、反应温度90 ℃、m（甲醛）/m（AlMCM-41）=7的反应条件下,在一定范围内,双酚F的产率随Al含量增加而增加,但在n（Si）/n（Al）＜50时,双酚F的产率反而下降,当n（Si）/n（Al）=50时,双酚F的产率最高,为42.28%。     

Studies on polyethylene glycol/polyethersulfone composite membranes for FCC gasoline desulphurization by pervaporation

A polyethylene glycol (PEG)/polyethersulfone (PES) composite membrane that can be applied on a commercial (or scale up) plant for fluid catalytic cracking (FCC) gasoline desulphurization was prepared through pre-wetting combined with double-layer coating methodology. Preparation methodology, morphologies characterization and performance test for the composite membranes were conducted. The results indicated that the pre-wetting method effectively confined the intrusion of PEG solution to porous PES support layer in coating process. The composite membrane had a clear-cut boundary surface between the dense active layer and the porous support layer, which was examined by scanning electron microscope (SEM). Pervaporation (PV) experiments indicated that the membrane, with the crosslinking agent amount of 17% and solids content in active layer solution of 16%, had a stable performance for FCC desulphurization. The sulphur enrichment factor came to 3.63, and the total permeation flux was 3.37 kg/m² h. It was found that the PV performance of the composite membrane changed slightly when the thickness of active layer varied from 4.25 μm to 33.26 μm.