温度对均相化学反应的影响

本文对实际生产中温度的一般影响进行了分析,并分别就温度对单一反应和复合反应的影响进行了探讨。温度对单一反应的影响从可逆和不可逆反应两方面入手,可逆反应又从可逆吸热和可逆放热两方面进行分析。温度对复合反应的影响从平行反应和串联反应两个角度展开进行探讨。最后得出在各种情况下温度对反应的影响规律。     

有机异氰酸酯光气化反应分析

利用化学反应工程的原理对有机异氰酸酯光气化反应进行了分析,认为其反应可以看作是一个平行－串联反应,并对这一类反应适合的进料方式进行了讨论。以此为基础,对现在异氰酸酯生产中光气化反应的工艺进行了分析,认为二步法光气化反应工艺优于一步法反应工艺。同时对各种形式的反应器优缺点进行了总结,并给出了不同条件下的最佳反应器形式,对以后新建异氰酸酯生产装置中光气化反应器的选择具有指导意义。     

氢氧化钙羰基化合成甲酸钙反应动力学

以半连续进料方式在高压搅拌釜中对氢氧化钙羰基化反应进行了系统的研究。采用XRD对反应产物进行了定性分析,证明反应生成物为甲酸钙和极少量的碳酸钙。与生成甲酸钙的主反应相比,生产碳酸钙的副反应速率较小可以忽略。考察了反应工艺条件对反应的影响,结果表明,转速达到1 000 r/min时,可以消除外扩散的影响。在反应温度423~453 K、压力2.0~3.5 MPa、不同氢氧化钙初始浓度下对反应进行考察,使用幂函数形式的动力学模型对实验数据进行拟合,结果表明,该反应对CO为一级反应,反应活化能为54.7 kJ·mol^-1。通过模型计算结果与实验数据的比较,证明该模型具有较好的实用性。     

反应精馏研究进展及应用前景

对反应精馏技术在工艺和模拟方面的研究进展进行了概述 ,简单介绍了反应精馏的关键技术并对反应精馏的应用前景进行了展望。     

对氨基苯磺酸制备的微型实验改进与探讨

苯胺与浓硫酸通过磺化反应来制备对氨基苯磺酸是有机化学实验教学中一个常见的反应。该实验常在烧瓶中进行高温反应制备。本文试管反应对微型反应进行了改进,优化了微型反应装置,增加了反应操控性和实验效果。     

反应精馏技术的研究现状及其应用

对反应精馏技术的的研究进展以及使用现状进行综述,对反应精馏塔及催化剂进行了一个详细的介绍,对反应塔中常见的几种处理模式和方法进行阐述,总结了所运用到的数学模型和反应;反应精馏技术的研究进展以及使用的现状进行综述,并对未来发展的可能方向进行了预测。     

反应精馏技术的研究现状及应用

对反应精馏技术的研究现状及其应用进行了综述,介绍了反应精馏塔及催化剂,对催化剂床中传质及流体力学特征,数学模型和反应精馏塔设计方程进行了总结;同时介绍了反应精馏技术的应用现状及其可能的应用领域。     

歧化反应的应用现状及进展

对歧化反应发生的原理、分类及判断方法进行了阐述,综述了歧化反应在国内外的应用,最后对歧化反应的应用研究进展进行了归纳和总结。     

苯酚与PAPI封闭反应条件的研究

对苯酚与多亚甲基多苯基多异氰酸酯（PAPI）的封闭反应进行了研究,探讨了温度、溶剂及反应时间对封闭反应的影响,利用红外光谱分析手段进行了表征.结果表明：升高温度有利于封闭反应的进行,最佳反应温度为80℃;极性溶剂对封闭反应有利,极性越大封闭反应越容易进行;添加催化剂能大大提高PAPI与苯酚封闭反应速率,缩短反应时间.     

甘油与醋酸反应的热力学分析

采用Benson基团贡献法,对甘油和醋酸反应进行了反应焓变、熵变、吉布斯自由能变的计算。讨论了反应温度对热力学平衡的影响。结果表明:生成单醋酸甘油酯、二醋酸甘油酯的反应能自发进行;生成三醋酸甘油酯的反应不能自发进行。平衡常数随着温度的升高而减小,提高反应温度不利于平衡向产物方向移动,必须及时将反应生成的水移出反应体系。     

An Efficient and Recyclable Catalyst for N‐Alkylation of Amines and β‐Alkylation of Secondary Alcohols with Primary Alcohols: SBA‐15 Supported N‐Heterocyclic Carbene Iridium Complex

A mesoporous silica (SBA‐15)‐supported pyrimidine‐substituted N‐heterocyclic carbene iridium complex was prepared and used as a catalyst for both environmentally friendly N‐alkylation of amines and β‐alkylation of secondary alcohols with primary alcohols. The structure of the supported iridium catalyst was characterized by Fourier transform infrared (FT‐IR), ¹³C and ²⁹Si solid‐state nuclear magnetic resonance (NMR), small‐angle X‐ray scattering (SAXS), transmission electron microscopy (TEM), iridium K‐edge X‐ray absorption near‐edge structure (XANES) and extended X‐ray absorption fine structure (EXAFS) spectroscopic analyses which demonstrated that the coordination environment of the iridium centre and the 3‐dimensional‐hexagonal pore structure of SBA‐15 were retained after the immobilization. The catalyst was found to be highly efficient for both kinds of reaction on a wide range of substrates under mild conditions. Moreover, the supported iridium catalyst was obviously superior to the unsupported one in the N‐alkylation of aniline and β‐alkylation of 1‐phenylethanol with benzyl alcohol as substrate, which indicated that not only the iridium complex moiety but also the support material contributed to the catalytic activity of the supported iridium catalyst in these reactions. The supported iridium catalyst can be easily recycled by simple washing without chemical treatment, and exhibited excellent recycling performance without notable decrease in catalytic efficiency even after twelve test cycles for N‐alkylation of aniline with benzyl alcohol, nine cycles for N‐alkylation of different amines with different alcohols, and eight cycles for β‐alkylation of 1‐phenylethanol with benzyl alcohol, respectively.     

相转移催化合成盐酸萘替芬

以萘和苯乙烯为起始原料 ,在多聚甲醛、冰醋酸和磷酸存在下进行氯甲基化反应 ,制备 1 -氯甲基萘 ,与 3 0 % (质量分数 )甲胺反应得 N-甲基 -1 -萘甲基胺 ;然后苯乙烯与甲醛和盐酸反应生成3 -氯 -苯丙烯 ;再经 N-烃基化反应合成抗真菌药物萘替芬。 N-烃基化反应中用 PEG-40 0 ,PEG-60 0作为固 -液体系相转移催化剂。避免使用昂贵的四氢硼钠 ,合成路线缩短 ,反应条件温和 ,操作简便。作为相转移催化剂的聚乙二醇催化效果优于溴化四丁基胺 ,合成 N-甲基 -1 -萘甲基胺时 ,用 PEG-40 0收率较高 ,合成萘替芬时 ,用 PEG-60 0 ,收率达 90 .6%。     

Amino-functionalized mesoporous silica as solid base catalyst for regioselective aza-Michael reaction of aryl tetrazoles

The modified MCM-41 with aminopropyl groups was synthesized, characterized and its catalytic activity was evaluated in aza-Michael addition of various aryl tetrazoles to activated olefin esters under reflux condition. The synthesized new compounds were characterized using spectroscopic and physical methods. The catalyst was reused in five consecutive experiments without obvious loss of activity. The results showed with application of aminopropylated MCM-41 only N2 alkylation occurs on tetrazole rings. However, when triethylamine was used as the base, a mixture of N1 and N2 alkylation was observed. In addition, antimicrobial studies investigated and results indicated that the products did not show considerable antimicrobial activity.     

负载型杂多酸催化甲苯异丙基化反应

以等体积浸渍法制备了负载型杂多酸PWH/SiO2催化剂,采用高压流动微反装置研究了其催化甲苯与异丙醇烷基化反应结果的规律,关联表征结果确定制备负载磷钨酸的适宜条件为：负载量40%,焙烧温度200℃。其催化甲苯与异丙醇烷基化反应适宜反应条件是：反应温度为200℃,甲苯与异丙醇的摩尔比为4∶1,体积空速为2h?1,在此条件下,异丙醇的转化率最高达到92.94%,烷基化反应选择性达83.89%。     

N-乙基哌嗪的合成研究

提出以哌嗪和溴乙烷为原料进行烷基化反应制备N 乙基哌嗪的合成路线 ,研究了原料与烷化剂的物质的量比、反应时间、反应温度、催化剂种类等因素对产品收率的影响。并确定了最佳反应条件。在最佳条件下 ,N 乙基哌嗪收率大于 90 % ,经分离精制得w(N 乙基哌嗪 ) =99%的产品。     

N,N′-二甲基喹吖啶酮的合成研究

采用N 烷基化反应,在喹吖啶酮上引入两个甲基,得到N,N′ 二甲基喹吖啶酮,该化合物具有良好的溶解性,能发出强烈的桔红色荧光。     

Improved Synthesis of Buprenorphine from Thebaine and/or Oripavine via Palladium‐Catalyzed N‐Demethylation/Acylation and/or Concomitant O‐Demethylation

An improved preparation of buprenorphine via palladium‐catalyzed N‐demethylation/acylation is reported. Three routes were investigated and compared in overall yield. The first involved N‐demethylation/acylation of an advanced intermediate obtained from thebaine followed by hydrolysis of the N‐acetamide and alkylation with cyclopropylmethyl bromide and/or reduction of the N‐acetyl group with the Schwartz reagent followed by N‐alkylation. The second route employed cyclopropylcarboxylic acid anhydride in the N‐demethylation/acylation protocol and subsequent reduction of the cyclopropylcarboxamide by either lithium aluminum hydride or under hydrosilylation conditions. Both of these routes originated in thebaine and therefore required O‐demethylation as a final step. The third route employed an N‐demethylation/acylation sequence starting from oripavine rather than thebaine, thus avoiding the O‐demethylation. The routes are compared for overall efficiency and experimental and spectral data are provided for all new compounds.     

稀土杂原子沸石合成条件对甲苯烷基化反应的影响

利用硝酸镧、硅酸和硫酸铝为原料，用正丁胺作模板剂合成［La］-AlZSM-5沸石。XRD和晶胞参数测定表明, 镧原子进入沸石骨架,部分取代了铝原子。考察了不同合成条件对甲苯烷基化反应的影响。实验结果表明，在凝胶碱度较低,晶化时间80 h,模板剂C₄H₁₁N/SIO₂为0.045条件下,合成的沸石催化剂性能最佳。［La］-AlZSM-5沸石催化剂具有很高的活性和选择性。当甲苯转化率为21.07％时,对乙基甲苯选择性达94.81％。     

Green and Scalable Aldehyde‐Catalyzed Transition Metal‐Free Dehydrative N‐Alkylation of Amides and Amines with Alcohols

In contrast to the borrowing hydrogen‐type N‐alkylation reactions, in which alcohols were activated by transition metal‐catalyzed anaerobic dehydrogenation, the addition of external aldehydes was accidentally found to be a simple and effective protocol for alcohol activation. This interesting finding subsequently led to an efficient and green, practical and scalable aldehyde‐catalyzed transition metal‐free dehydrative N‐alkylation method for a variety of amides, amines, and alcohols. Mechanistic studies revealed that this reaction most possibly proceeds via a simple but interesting transition metal‐free relay race mechanism.     

一种新的双叔胺化学萃取剂的研究

以十二烷基苯为原料,经硝化、加氢和Ｎ 烷化制得一种以双叔胺２,４ 二（Ｎ,Ｎ 二己基）氨基十二烷基苯为主要成分的新萃取剂。其中硝化采用混酸硝化法,分两步进行,收率为９２．６％;加氢采用５％（ｗ）钯－炭催化剂,在５５℃、１．２～０．５ＭＰａ下进行,收率为９２．０％;Ｎ 烷化采用季铵盐相转移催化剂催化,在氢氧化钠水溶液中、回流温度下进行,最终产物中主产物含量不低于５１．６％。在异辛醇为稀释剂、２５℃及相比为１的萃取条件下,该萃取剂对硫酸的萃取率比三辛胺提高了５６．９％。