氯丙烯环氧化与蒽醌法生产过氧化氢过程集成研究

对两种不同的氯丙烯环氧化与蒽醌法生产过氧化氢过程的集成方法进行了研究。在集成过程Ⅰ中,氯丙烯环氧化与氢蒽醌氧化在同一反应器中同时进行;在集成过程Ⅱ中。用甲醇／水溶剂萃取氧化工作液中的过氧化氢直接用于环氧化反应。实验考察了溶剂、工作液中氢蒽醌浓度和原料配比对集成过程Ⅰ的影响;环氧化产物对工作液氢化及少量工作液组分对环氧化反应的影响。结果表明,加入甲醇可提高环氧氯丙烷收率;工作液中氢蒽醌浓度过高对环氧化不利;环氧化产物对工作液氢化没有影响;少量工作液组分对环氧化没有明显影响。     

TS-1催化H2O2与甲基氯丙烯环氧化

以TS-1为催化剂,以30％（质量分数）H2O2为氧化剂催化2-甲基-3-氯丙烯（MAC）环氧化,考察了溶剂种类与用量、反应温度、反应物摩尔配比及催化剂TS-1质量浓度等因素对环氧化反应的影响。结果表明,反应的最佳溶剂为甲醇;增加催化剂质量浓度和升高反应温度均有利于提高转化率和H2O2有效利用率,但同时降低了反应的选择性;从反应物摩尔配比兼顾反应的转化率和H2O2有效利用率两方面来考虑,本试验条件下选1：1为佳。     

环氧氯丙烷合成新工艺

采用磷钨杂多酸盐/TiO2为催化剂,以35%双氧水溶液为氧源催化氯丙烯进行环氧化反应合成了环氧氯丙烷,考察了反应条件对环氧化反应的影响。结果表明,通过加入适量的磷酸二氢铵能抑制环氧氯丙烷的水解而提高环氧氯丙烷的收率。氯丙烯环氧化反应的适宜条件为：以氯丙烯为原料和反应溶剂,磷酸氢二铵用量（相对于总反应物的质量分数）0.04%,反应温度45～50℃,反应时间4 h,n（氯丙烯）∶n（H2O2）=5∶1,n（催化剂）∶n（H2O2）=1∶100。在此条件下,H2O2的转化率为98.6%,环氧氯丙烷的选择性和收率分别为91.2%和85.4%。该催化剂的稳定性好,回收的催化剂性能接近新鲜催化剂。     

6-甲氧基-7-乙氧基-4-氯喹啉的合成改进

以2-甲氧基-5-硝基苯酚为起始原料,经过O-烷基化、还原、高温合环、水解、脱羧、氯化6步反应,得到目标产物6-甲氧基-7-乙氧基-4-氯喹啉,总收率为24%。O-烷基化过程中,通过对丙酮、乙腈、DMF做溶剂的对比,发现乙腈做溶剂时,不仅产率较高,且后处理简单。在高温合环过程引入"一锅法"和"无溶剂法",不仅简化操作步骤,提高产率,而且降低了反应的污染。     

手性麻黄素-卟啉锰催化剂的合成及催化性能的研究

以一类新型的手性麻黄素 -卟啉作配体 ,制备了金属锰配合物。考察了配合物对烯烃环氧化反应的催化性能 ,发现含麻黄素基团的锰卟啉催化剂在烯烃环氧化的两相溶剂 ( CH2 Cl2 /H2 O)体系中 ,不仅催化活性增强 ,同时具有相转移能力。还探讨了反应条件对环氧化结果的影响规律     

二乙基二烯丙基氯化铵的制备

研究了二乙基二烯丙基氯化铵的合成方法以及几种溶剂对反应的影响。结果表明，在以丙酮为溶剂，叔胺与氯丙烯等体积比，时间限定的条件下，季铵盐的收率最高。     

氯丙烯环氧化反应器气相安全控制条件

在相转移法氯丙烯环氧化反应过程中,由于少量双氧水发生无效分解生成氧气,导致反应器气相存在燃爆危险性。测试了工况条件下氯丙烯-氧-氮三元体系的燃爆特性,得出该体系的极限氧浓度值(LOC)为10.9%;考察了主要因素对气相氧浓度的影响。研究发现,要降低气相氧浓度,应尽可能降低催化剂用量,适当提高搅拌速度,严格控制H_2O_2用量;应在液相沸腾后开始H_2O_2进料,并控制反应初始阶段的H_2O_2进料量,以避免瞬间H_2O_2进料过快。     

环戊烷氧化制环戊醇和环戊酮工艺研究

以价格低廉的环戊烷为原料开发高附加值的环戊醇和环戊酮产品,研究了钛硅分子筛催化氧化环戊烷制备环戊醇和环戊酮的反应工艺,在固定床反应器中考察了不同工艺条件对反应性能的影响。结果表明,在以丙酮为溶剂,n(环戊烷)/n(过氧化氢)为1,n(丙酮)/n(环戊烷)为8～10,反应温度为70℃,反应压力为0.5MPa,液时空速为2.0h~(-1)条件下,醇酮产品收率大于25%,醇酮比为0.3～0.45。     

7-溴-2,3-二氢-1-茚酮的合成新方法研究

本文以邻溴苯甲醛为原料,经亲电加成反应、氧化反应以及分子内Friedel-Crafts烷基化反应合成了7-溴-2,3-二氢-1-茚酮。研究发现,分子内Friedel-Crafts烷基化是影响总收率的关键步骤,探讨了反应溶剂、反应温度、反应时间等条件对反应的影响。同时,对氧化反应步骤中氧化剂及反应溶剂进行了筛选,结果发现,在以丙酮为溶剂琼斯试剂为氧化剂的条件下,产物收率最高。所有产物经NMR和MS进行确证。     

Salen金属配合物催化氧化环己烷制备环己酮

制备了[Fe（Ⅲ）（salen）Cl]、[Mn（Ⅲ）（salen）Cl]和[Co（Ⅱ）（salen）]3种催化剂,并将其应用于环己烷催化氧化的工艺中。实验以H2O2和过氧化氢叔丁基为氧化剂,乙腈或丙酮作为溶剂,在60℃温度下进行了反应。结果表明,在以丙酮为溶剂、[Co（Ⅱ）（salen）]为催化剂的过氧化氢体系中反应6h,环己烷的转化率达62．5％。     

Eco-friendly synthesis of epichlorohydrin catalyzed by titanium silicate (TS-1) molecular sieve and hydrogen peroxide

In a mixed solvent system of acetonitrile and methanol, titanium silicate molecular sieve, TS-1, having MFI topology, efficiently catalyses the epoxidation of allyl chloride to the corresponding epichlorohydrin in excellent yields using dilute hydrogen peroxide (45%) as an oxidizing agent.     

Epoxidation of allyl alcohol to glycidol using titanium silicalite TS-1: effect of the reaction conditions and catalyst acidity

The epoxidation of allyl alcohol to glycidol using the titanium silicalite TS-1 with hydrogen peroxide as the oxidant is described and discussed in detail. The reaction conditions (alcohol, solvent, temperature) required to obtain 100% selectivity to glycidol are described and this selectivity has been observed at conversions of allyl alcohol of up to 20%. Addition of excess hydrogen peroxide enhances conversion but does not appear to affect selectivity to glycidol deleteriously, whereas addition of hydrogen peroxide over an extended time period is not particularly beneficial. The major side reactions are the oxidation of the alcohol solvent and the ring opening solvolysis of the glycidol that leads to the formation of alkoxy diols. Base treatment of the TS-1 using sodium azide enhances the glycidol selectivity, whereas the incorporation of Brønsted acid sites by addition of aluminium into the framework structure of TS-1 enhances the selectivity to the products of solvolysis ring opening reactions.     

Solvent effects in the epoxidation reaction of 1-hexene with titanium silicalite-1 catalyst

The epoxidation of 1-hexene with titanium silicalite-1 (TS-1) catalyst was investigated to gain insight into the effect of the solvent on the observed reactivity. Three different solvents were examined: methanol, acetonitrile, and acetone. Kinetic data were obtained from batch reaction experiments, with an emphasis placed on gathering more accurate initial rates than those reported in the literature. The dependencies of the rates on the concentrations of 1-hexene, water, and hydrogen peroxide were determined. The adsorption behavior of 1-hexene in TS-1 in the three different solvents was determined independently by batch sorption experiments. Results showed that the solvent has a significant effect on the adsorption of 1-hexene, and hence on the reaction kinetics. Kinetic modeling incorporating experimental and simulated quaternary adsorption isotherms to describe quasi-equilibrated steps revealed that the differences in the observed reaction kinetics may be attributed mostly, but not entirely, to differences of the partitioning of 1-hexene between the bulk and intraporous phases among the three different solvents.     

Influence of Pt–Pd/TS-1 Catalyst Preparation on Epoxidation of Olefins with Hydrogen Peroxide

The catalytic performance of the platinum–palladium/titanium silicalite, which was a common catalyst for the direct epoxidation of olefins with hydrogen and oxygen, was tested by epoxidation of allyl chloride with hydrogen peroxide. The epoxidation capacity of the TS-1catalyst was reduced after loading palladium and platinum on it. Ti leaching and crystallinity decrease were observed by XRD and FT-IR. The decomposition of hydrogen peroxide was accelerated by the supported Pd and Pt. These contributed to the loss of epoxidation capacity of TS-1. Ti leaching and crystallinity decrease were probably main causes. We propose that the Ti leaching had the most important influence on the loss of epoxidation capacity     

氯丙烯催化环氧化钛催化剂研究进展

主要介绍了TiO2／SiO2、TS-1及其改性的TS-1等催化剂催化氯丙烯直接环氧化制备环氧氯丙烷的近期研究进展，对各方法的特点和发展前景进行了讨论，并指出了氯丙烯直接环氧化制备环氧氯丙烷的难点和发展趋势。     

Epoxidation of allyl alcohol to glycidol using titanium silicalite TS-1: effect of the method of preparation

The epoxidation of allyl alcohol with hydrogen peroxide catalysed by the microporous titanium silicalite TS-1 has been investigated with respect to the effect of the method of catalyst preparation. Three methods of TS-1 synthesis have been studied using the standard tetrapropyl-ammonium cation as template (i) using tetraethyl orthosilicate, tetraethyl orthotitanate as reagents, (ii) using a fluoride method and (iii) using tetrabutyl orthotitanate as the titanium source. The TS-1 samples were characterised by electron microscopy, X-ray diffraction and infrared spectroscopy. The method of preparation controlled the morphology of the TS-1 crystals and in particular the crystallisation time was found to be an important parameter. Data are presented that correlate the activity for the epoxidation of allyl alcohol with the morphology of TS-1. In addition it is found that the catalytic activity of TS-1 for this reaction is not related to the intensity or presence of the infrared absorption band at ca. 960 cm^–1.     

Catalytic epoxidation with electrochemically in situ generated hydrogen peroxide

The epoxidation of allyl alcohol with in situ generated hydrogen peroxide was performed in an electrochemical cell with a trickle-bed electrode, composed of carbon black, graphite, PTFE and titanium silicalite-1 (TS-1) as heterogeneous epoxidation catalyst. Mass transport in interaction with the catalytic activity limits the epoxidation rate. The conversion of allyl alcohol increases with increase in the content of epoxidation catalyst in the electrode. In contrast, the specific reaction rate decreases due to the reduced accessibility of active sites in the catalyst.     

Phase Equilibrium of Reaction Mixtures for the Production of Epichlorohydrin in the Presence of Solvents

Theoretical Foundations of Chemical Engineering - An alternative solvent for the production of epichlorohydrin via the epoxidation of allyl chloride with an aqueous hydrogen peroxide solution over...     

Catalytic mechanism and reaction pathway of acetone ammoximation to acetone oxime over TS-1

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.     

Catalytic oxidation of anisole over titanium silicalite-1

The reaction of anisole hydroxylation with hydrogen peroxide to form methoxyphenols over TS-1 was studied. Four C1-C3 alcohols and the two aprotonic solvents acetone and acetonitrile were used. Product conversion was almost proportional to the titanium content of the catalyst sample. The highest conversion and p-selectivity were observed in ethanol. Some speculations, based on the formation of substrate-solvent or titanium-solvent-oxidant complexes, about the role of the solvent are presented. It was found that in all the solvents studied the p/o ratio increased with time.