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综述了基于钛硅分子筛/过氧化氢体系的环己酮液相氨肟化绿色工艺中钛硅分子筛TS–1的研究进展,包括传统水热合成工艺的优化、新合成方法的开发和增强TS–1传质的新策略。总结了钛硅分子筛催化环己酮氨肟化的反应机理、反应路径和催化剂再生方法。并对今后钛硅分子筛催化材料的开发和研究做出展望。 相似文献
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采用无机钛硅原料合成了钛硅分子筛TS-1,经酸处理后对合成的钛硅分子筛TS-1进行二次晶化修饰改性.用X射线衍射仪(XRD)、傅立叶红外光谱(FT-IR)和扫描电子显微镜(SEM)对二次晶化后的钛硅分子筛进行表征,发现晶粒变小,钛进入了分子筛的骨架中.考察了二次晶化后的催化剂对环己酮氨氧化反应的催化性能.结果表明,二次晶化法可提高TS-1分子筛的催化性能,在氨、环己酮和过氧化氢的物质的量之比为2.0∶1.0∶1.5、催化剂用量为18 g/mol和75 ℃的条件下,反应4 h后,过氧化氢的转化率、环己酮的转化率和环己酮肟的收率分别为98.12%,97.07%和93.33%. 相似文献
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环己酮氨肟化工艺是己内酰胺新技术发展的必然趋势之一,而钛硅分子筛TS-1的制备是环己酮氨肟化工艺的核心技术。但由于TS-1合成成本昂贵,合成条件苛刻,制备重复性差,制约了工业化的发展,仍需要不断的技术进步。本文针对这一主题,对环己酮氨肟化反应所需的TS-1催化剂的制备包括TS-1的改性、大颗粒TS-1的制备、复合TS-1的制备、TS-1的成型及其他的TS-1制备工艺等技术进行了系统综述。在环己酮氨肟化反应中,提高TS-1的催化活性、解决工业上TS-1的分离和回收难题、提高TS-1制备的稳定性和产量、降低成本等是未来TS-1研究的发展趋势。 相似文献
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针对钛硅分子筛(TS-1)催化环己酮氨肟化反应在浆态条件下进行时存在的固液分离和溶剂回收等问题,尝试采用微乳化的方法加以解决。以十六烷基三甲基溴化铵(CTAB)/水/氨水/环己酮的水包油(O/W)型微乳液作为反应介质,实现了TS-1催化环己酮的氨肟化反应。通过实验考察了反应温度及助表面活性剂(叔丁醇)的用量对反应选择性及转化率的影响。结果表明,升高反应温度,在环己酮转化率随之提高的同时,环己酮肟的选择性先升高后降低,且在65℃时达到最高;而助表面活性剂(叔丁醇)的用量对环己酮的转化率没有明显影响,却显著影响了反应的选择性。X射线衍射图和傅立叶变换红外谱图显示,所得的环己酮肟结晶度好、纯度高。 相似文献
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对应用于环己酮氨氧化制环己酮肟工艺中的催化材料进行了归纳,主要包括TS-1、含钛分子筛等,叙述了近几年来TS-1分子筛的相关成果.尽管目前TS-1催化剂已取得较大的进展,但在一定程度上仍存在着催化剂成本高、反应液与催化剂分离困难、反应液堵塞催化剂孔道导致失活的现象.基于上述问题,针对现有催化材料研究进展和工业化应用水平... 相似文献
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TS-1催化环己酮氨氧化反应本征动力学模型 总被引:5,自引:2,他引:3
由TS-1催化环己酮氨氧化反应机理出发,分析了反应过程的特点及反应规律,根据推测的机理,建立了反应本征动力学模型.结合搅拌釜中测得的动力学数据,对动力学模型进行了参数估值及模型筛选.结果表明,假设反应合乎羟胺机理、双氧水吸附、表面反应为控制步骤时所导出的模型能较好地拟合实验数据,并满足统计检验.根据该动力学模型,通过模拟计算对部分操作条件进行了分析和优化. 相似文献
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An innovative green process of producing ε-caprolactam was proposed by integrating ammoximation and Beckmann rearrangement effectively. As a first part of the new process, TS-1 molecular sieve-catalyzed synthesis of cyclohexanone oxime from cyclohexanone, ammonia and hydrogen peroxide was carried out in a batch plant. Cyclohexane was used as the solvent in the three-phase reaction system. The influences of essential process parameters on ammoximation were investigated. Under the reaction conditions as catalyst content of 2.5% (by mass); H 2 O 2 /yclohexanone molar ratio of 1.10; NH 3 /cyclohexanone molar ratio of 2.20; reaction temperature of 343 K; reaction time of 5 h, high conversion of cyclohexanone and selectivity to oxime (both>99%) were obtained. Thus, the three-phase ammoximation process showed equal catalytic activity as TS-1 but much more convenient and simpler for the separation of catalyst in comparison to the industrial two-phase system with t-butanol used as solvent. 相似文献
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Zhaohui Li Rizhi Chen Wanqin Jin Weihong Xing 《Korean Journal of Chemical Engineering》2010,27(5):1423-1427
A series of two-step reactions and several special experiments were designed and carried out to discover the reaction pathway
of acetone ammoximation to acetone oxime over titanium silicalites-1 (TS-1) employing 25 wt% ammonia and 30 wt% hydrogen peroxide
as the ammoximation agents. The experimental results show that the acetone oxime can form even if there is no direct contact
between acetone and TS-1 catalysts, indicating the hydroxylamine route may be the most important catalytic mechanism for the
reaction. HPLC, GC/MS and ion chromatography characterization results show that hydrogen peroxide can oxidize acetone oxime
to acetone, nitrite and nitrate in the presence of TS-1. In addition, nitrite and nitrate can form in the reaction of H2O2 and NH3 over TS-1. Based on these results, a possible overall reaction pathway of acetone ammoximation over TS-1 has been proposed. 相似文献
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《Journal of Catalysis》2006,237(2):359-367
The liquid-phase ammoximation of cyclohexanone with ammonia and hydrogen peroxide was conducted over Ti-MWW. Ti-MWW is capable of giving both cyclohexanone conversion and oxime selectivity >99% under optimum reaction conditions. It is a highly active, selective, and reusable catalyst for the synthesis of cyclohexanone oxime in the presence of water. In comparison to other titanosilicates, Ti-MWW shows much higher catalytic activity, even superior to that of TS-1. The catalytic performance of Ti-MWW depends greatly on the operating conditions of the reaction, especially the method of adding substrates. The reason why the method of adding substrates plays such an important role in the ammoximation of ketones or aldehydes over Ti-MWW was investigated after a detailed evaluation of the reaction mechanism. 相似文献
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基于陶瓷膜反应器开发出无有机溶剂的环己酮氨肟化新工艺,探讨TS-1催化剂失活机制。采用XRD及Rietveld全谱拟合、FT-IR、N2吸附-脱附、TGA/DSC、GC-MS等手段对TS-1分子筛的骨架结构、晶胞参数、比表面积和有机物种类进行了表征分析。结果表明,无有机溶剂的环己酮氨肟化反应过程中,存在硅流失的现象,但TS-1骨架完整,晶胞参数未明显变化;环己酮、环己酮肟及反应副产物等吸附在TS-1催化剂的表面及孔道内,使比表面积下降52.6%、孔体积减少了41.6%,是造成TS-1失活的主要原因,空气氛围中于600℃煅烧3 h,可以恢复催化剂的活性。 相似文献
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TS-1催化丙酮氨氧化制丙酮肟的本征动力学研究 总被引:1,自引:2,他引:1
丙酮肟是一种优良的除氧剂.TS-1催化丙酮氨氧化合成丙酮肟是一种新型绿色工艺.借助高效液相色谱技术,研究了在TS-1分子筛催化下以氨、过氧化氢直接氧化丙酮为丙酮肟的本征反应动力学.在本实验条件下,TS-1催化剂平均粒径为200nm,内扩散可以忽略,当搅拌速度大于580 r·min-1时,外扩散已基本消除,反应进入动力学控制区;反应对于丙酮、过氧化氢和氨的反应级数分别为0.87、0.05和1.0,反应活化能为101.88 kJ·mol-1,反应指前因子为5.20×1013mol-092·L0.92·min-1.这可为TS-1催化-膜分离耦合制备丙酮肟过程开发提供基础数据. 相似文献
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纳米碳纤维(CNF)是一种新型的碳基催化剂载体。采用机械湿混的方式制得了混合型钛硅分子筛/纳米碳纤维(TS-1/CNF)催化剂,研究了其在水相体系中的过滤性能,以及在环己酮氨氧化反应中的催化活性。与单独TS-1相比,混合型TS-1/CNF催化剂的团聚体宏观尺寸较大,CNF交织形成的大量大孔非常有利于液体的穿透,使得TS-1/CNF催化剂具有良好的过滤性能,因而可改善TS-1在水相体系中的分离问题。SEM观察显示,CNF具有独特的长纤维结构以及较大的外表面,为TS-1微粒提供了较多的附着点,使得TS-1能均匀分布在CNF表面上。TS-1颗粒与直径处于相同尺度的CNF之间可能存在着较强的分子间作用力、静电作用力及疏水作用力,可避免分散和过滤过程中两者的分离。混合型TS-1/CNF催化剂上环己酮氨氧化反应的结果表明,环己酮的转化率接近100%,环己酮肟收率达98.4%,与纯TS-1的催化活性相当。 相似文献
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In the new EniChem process cyclohexanone oxime is directly synthesized by ammoximation of cyclohexanone with ammonia and hydrogen peroxide on titanium silicalite catalyst. The ammoximation reaction is suitable for the synthesis of several oximes by reaction of the corresponding ketones with ammonia and hydrogen peroxide on titanium silicalite. New results on ketones ammoximation and on reaction byproducts are reported. The effect of some reaction parameters on the oxime yield and on byproducts formation is discussed. 相似文献