The Reductive Amination of Aldehydes and Ketones and the Hydrogenation of Nitriles: Mechanistic Aspects and Selectivity Control

This review deals with two of the most commonly used methods for the preparation of amines: the reductive amination of aldehydes and ketones and the hydrogenation of nitriles. There is a great similarity between these two methods, since both have the imine as intermediate. However, due to the high reactivity of this intermediate, primary, secondary and/or tertiary amines are obtained (often simultaneously). The relation of the selectivity to different substrate structures and reaction conditions is briefly summarised, the main focus being on the catalyst as it is the most significant factor that governs the selectivity. Different mechanisms are discussed with the view to correlate the structure of the catalyst and, more particularly, the nature of the metal and the support with selectivity. The crucial point is the presumed location of the condensation and hydrogenation steps.     

Amination of Polyethylene Glycol to Polyetheramine over the Supported Nickel Catalysts

Surface nickel (NiO _x ) species, surface NiAl _x O _y compound, and NiO crystallites are present on the Ni/Al₂O₃ catalysts, and the ratio of these nickel species is dependent on the nickel loading. Surface nickel interacts with the TiO₂ support to form a surface nickel titanate compound (NiTiO _x ) which has a lower reducibility. The weak interaction between the surface nickel and the silica support results in the formation of NiO crystallites on the SiO₂ surface. The Ni/Al₂O₃ and Ni/TiO₂ catalysts contain new surface Lewis acid sites and the amount of surface Lewis acid sites increases with increasing nickel concentration. The Ni/SiO₂ catalysts have no sign of the presence of the surface Lewis acid sites. Only the Ni/Al₂O₃ catalysts have shown the ammonia adsorption at temperature of 200°C. Supported nickel on alumina catalysts possess the highest amination conversion, and the amine yield increases with increasing nickel loading up to 15% and starts to level off. By comparing amination catalysis with quantitatively TPR studies of the H₂ consumed of the Ni/Al₂O₃ catalysts, it appears that the dispersed nickel species are the active sites for amination. In addition, the amination product is mainly the secondary amine due to the presence of water.     

氧化胺化反应合成2-氨基-6-甲氧基-3-硝基吡啶

以氨水为胺化剂,KMnO4为氧化剂,在不同反应条件下实现2-甲氧基-5-硝基吡啶6位的氧化胺化反应,探讨了溶胡类型、氨水浓度等反应条件对目标化合物产率影响。结果表明,以KMnO4,NH3／DMSO,H2O为氧化胺化体系,在30℃条件下持续通入氨气,反应时间4h,2-氨基-6-甲氧基-3-硝基吡啶收率最高达到92．5％。     

气相色谱法同时测定火锅底料中多种有机磷农药残留

建立同时测定火锅底料中17 种有机磷农药残留的气相色谱法。样品经凝胶渗透色谱、固相萃取小柱净化,DB-1701 毛细管气相色谱柱分离,采用火焰光度检测器检测。火锅底料中17 种有机磷农药的加标回收率为81.83%～105.4%,RSD 为0.9%～5.2%,检出限(LOD)为1.0～5.3μg/kg。该方法具有快速、准确、检出限低等特点,能满足火锅底料中多种有机磷农药残留检测的需要。     

用于脂肪醇胺化的三元催化剂Cu-Ni-La的研究

脂肪醇胺化制备单长链叔胺工艺的技术关键之一在于催化剂的选择性。以月桂醇与二甲胺反应评价了以Cu和Ni为活性组分,碳酸钙为载体的负载型三元催化剂Cu-Ni-La的选择性,并对该催化剂进行了XPS研究。结果发现,在相同的铜镍比条件下,稀土元素La的加入降低了产物中高沸物双长链叔胺的生成量,La的加入对氧化态Cu的还原无明显影响,但抑制了氧化态Ni的还原,而催化剂的选择性与催化剂中的Ni的还原程度密切相关。     

壳聚糖吸附剂的制备及性能

通过以壳聚糖为原料,经交联、羟丙基氯化及胺基化,制备了壳聚糖胺基吸附剂。经红外光谱和扫描电镜测定其结构,研究了不同的胺化试剂及其用量对壳聚糖吸附剂胺基含量的影响及对中药液中黄酮化合物的吸附性能。结果表明,改性壳聚糖微球胺基含量比壳聚糖高,对游离黄酮的吸附量随着胺基含量增加而增加。     

用膜回收炼厂瓦斯气中氢气存在的问题及解决方法

针对采用中空纤维膜回收炼油厂富氢瓦斯气中的氢气，出现膜分离器前精密过滤器压降大，膜分离器前过滤器、法兰处出现黄色、黑色粉末固体颗粒，过滤器爆裂、膜分离性能下降、膜分离失效等严重影响膜使用寿命的问题。通过对炼油厂富氢气中的组分分析，探讨粉未形成机理，找出问题的主要原因是个别富氢气源H2S含量过高，不同气源中所含杂质不同，混合后可产生化学反应。提出在未实施水洗方案或不同类型富氢气分别回收氢前，加强脱硫装置操作，防止H2S含量高对膜的影响。将不同类型的富氢气分别处理，或通过水洗净化气体，可使膜分离器运行正常。     

Investigation of Dow Cyclotene 4026 surface amination by downstream plasma treatment

Dow Cyclotene 4026 surfaces were treated by downstream ammonia cold plasma with and without argon plasma pretreatments. The modified polymer surfaces were characterized by X‐ray photoelectron spectroscopy, Fourier transform infrared‐attenuated total reflection, and atomic force microscopy (AFM). A 2 fractional factorial design was developed to identify the optimal processing parameters. Further experimental investigation has also been conducted to optimize the operating conditions. The combined results show that the extent of surface amination of Cyclotene grows with increase of power, pressure, and temperature of ammonia plasma treatments both with and without argon plasma pretreatments. For the treatment time effect, the results indicate that N/C (nitrogen/carbon) ratios increase with time and then start to slightly decrease at the ～4‐min point, which may be tentatively explained by a competition between the modification process and the degradation process on the polymer surfaces. AFM results suggest that the upper limit of the operating condition to obtain a desirable surface topography is 175°C. Based on all the results from Design of Experiment, experimental data, and AFM analysis, the optimum processing parameters have been suggested. Finally, the aging effect of aminated surfaces is discussed; further investigation of this effect is still underway. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 2418–2427, 2005     

二乙胍硫酸盐的合成研究

本研究选用S－甲基异硫脲硫酸盐与二乙胺反应,选择合适的反应条件合成二乙胍硫酸盐,以S－甲基异硫脲硫酸盐计,收率达到75％。     

脂肪醇催化胺化制叔胺工艺技术现状及前景

脂肪醇催化胺化制叔胺的工艺是目前生产脂肪叔胺的主要方法,和传统的酸法工艺相比具有明显的优势。该工艺的技术关键为胺化催化剂及工艺放大。催化剂的开发水平已经能够满足工业化生产的要求,但基础理论研究不够广泛的深入。要想进一步提高催化剂的水平。要从基础理论入手。工程放大主要是解决气、液、固三相之间的传质问题,可以通过反应器形式的改进来实现,如采用环路反应器及固定床反应器等。要从根本上解决国内目前叔胺生产厂家多但规模小的问题,需要在工程化问题上有所突破。