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1.
异氰尿酸三苄基酯的合成研究   总被引:1,自引:0,他引:1  
采用N,N-二甲基甲酰胺作溶剂,异氰尿酸、苄氯为原料合成了异氰尿酸三苄基酯。通过正交实验得最佳反应条件为原料摩尔比异氰尿酸∶苄氯∶三乙胺=1∶3.1∶3.2,反应温度160℃,反应时间4h,溶剂DMF6.5ml/g异氰尿酸。该条件下产率达85%以上  相似文献   

2.
A reactive solvent was obtained by reacting 1 mol of cyclohexanone with 5 mol of formaldehyde. The structure of the solvent was studied by using 1H‐NMR and IR spectroscopy. It was used for solubilization of melamine and other heterocyclic compounds containing ? NH? groups, such as adenine, carbazole, cytozine, guanine, thymine, and uracyl, as well as isocyanuric, barbituric, and uric acids. The solubilization involved the reaction of formaldehyde (liberated at an elevated temperature) with amino groups of the compound. Melamine was the compound with the best solubility in the reactive solvent. Preliminary attempts of curing the solutions have also been made. The oligomers cured at 120°C in the presence of acidic catalysts. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2650–2659, 2002  相似文献   

3.
刘勇  唐有根  彭志光 《广州化工》2011,39(11):90-92,129
采用掺杂ML(Ni3.69Co0.72Mn0.35Al0.24)贮氢合金形成的氢化物作为氢源及催化剂,加氢还原对硝基甲苯生成对甲苯胺进行了研究。利用GC—MS和GC分别对产物进行定性和定量分析,同时用XRD对合金进行了研究。结果表明:该催化剂可以在温和条件下将对硝基甲苯加氢还原成对甲苯胺,未检测到副产物的产生,对甲苯胺选择性高达100%,且反应后催化剂与反应体系容易分离。并详细探讨了催化剂用量、不同溶剂、反应温度和反应时间等对反应的影响。结果表明:催化剂的含氢量与催化剂的活性密切相关,溶剂的性质对反应有明显影响,以无水乙醇为溶剂时催化剂性能最好,重复使用5次仍具有较高的催化活性。  相似文献   

4.
陈献  乔旭  崔咪芬  张进平  汤吉海 《精细化工》2005,22(11):874-877
采用相转移催化剂,氯代环已烷与二硫化钠溶液反应合成了二环已基二硫醚。考察了相转移催化剂的种类、原料摩尔比、反应温度等对反应的影响,比较了相转移催化与溶剂法合成的反应结果。得到的最佳反应条件为:以PTC3为相转移催化剂,反应温度96℃,n(Na2S)∶n(S)∶n(C6H11C l)=1∶0.8∶0.8,氯代环己烷的转化率为98.8%,二环已基二硫醚的选择性为81.4%。与溶剂法相比,反应时间由12~15 h缩短到10 h,收率提高了10%,避免了因使用溶剂带来的后处理问题。  相似文献   

5.
A new method of preparation of oligoetherols containing perhydro‐1,3,5‐triazine rings from isocyanuric acid and an excess of glycidol, alkylene carbonates, or oxiranes is presented. The course of reaction was studied at various molar ratios of glycidol to isocyanuric acid. The structure of the products was established, and some physical properties were measured. The oligoetherols were demonstrated to be useful substrates for polyurethane foams of enhanced thermal stability. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011  相似文献   

6.
用三氯异氰尿酸制备二氯异氰尿酸钠.为了满足实际需要,方便生产操作,进行了生产工艺改进.试验表明,控制反应澄清液的终点pH值在6.5~7.0范围内,可得到有效氯含量高的二氯异氰尿酸钠产品.  相似文献   

7.
《Journal of Catalysis》2005,229(2):439-445
The influence of the support, the metal precursor, and the solvent on the selective hydrogenation of paracetamol (4-acetamidophenol) was studied over supported ruthenium catalysts. The catalysts supported on the oxidic supports Al2O3 and SiO2 gave the best results in terms of activity, selectivity for the acetamidocyclohexanols (99%), and stereoselectivity for the trans isomer (53 and 46%, respectively). Carbon-supported catalysts produced larger amounts of secondary compounds, mainly N-cyclohexylacetamide, which was derived from the hydrogenolysis reaction of the OH group. The use of a chloride precursor resulted in the enhancement of the formation of N-cyclohexylacetamide and partially hydrogenated products; the stereoselectivity also increased. Moreover, because of the acidity caused by residual Cl, condensation led to oligomers of paracetamol. In spite of the decrease in the selectivity for cyclohexanol derivatives when the more polar solvent ethanol was used instead of isopropanol or tetrahydrofuran the stereoselectivity for the trans isomer increased from 30 to 38%.The results confirm that the factors studied affect the mode of adsorption of the molecule of paracetamol on the catalyst in different ways. These effects determine the product distribution and the selectivity of the reaction.  相似文献   

8.
采用共沉淀法制备系列铁磁性氧化物负载的钴、铑及钴铑双金属催化剂。研究以三苯基膦改性的Co/Fe3O4、Rh/Fe3O4和Co-Rh/Fe3O4催化剂对双环戊二烯氢甲酰化合成三环癸烷二甲醛的催化性能,并对催化剂进行XRD、FT-IR和TPR等表征。结果表明,Co-Rh/Fe3O4催化剂对双环戊二烯氢甲酰化合成三环癸烷二甲醛具有最高的选择性。双环戊二烯氢甲酰化合成三环癸烷二甲醛的过程与反应压力、催化剂与双环戊二烯的质量比、反应温度和溶剂的种类有关。增加催化剂与双环戊二烯质量比和升高温度及压力有利于双环戊二烯的转化和三环癸烷二甲醛选择性,采用极性相对较小的溶剂有利于三环癸烷二甲醛的形成。催化剂重复使用5次,催化活性几乎不变。 在催化剂与双环戊二烯质量比为2∶15、Rh的负载量为1∶100、反应温度140 ℃、反应压力7 MPa和反应时间5 h条件下,双环戊二烯转化率达99%以上,三环癸烷二甲醛选择性达60%以上,进一步延长反应时间至12 h,三环癸烷二甲醛选择性超过90%。  相似文献   

9.
探讨了以马来酸为原料两条路线合成丁二酸二甲酯的效果,结果表明,马来酸先酯化后加氢的技术路线具有选择性高、速率快的明显优势。考察了水和甲醇作溶剂,对马来酸酯化产物加氢反应选择性的影响。结果表明,在反应温度50~70℃、压力0.4~1.2 MPa的低温低压的温和条件下,马来酸二甲酯转化率、丁二酸二甲酯的选择性和收率分别为100%,100%和99.5%以上;氢氧化钌催化剂具有良好的催化性能,催化剂使用5釜后,反应时间开始延长,但不影响丁二酸二甲酯的选择性。  相似文献   

10.
《化学世界》2006,47(4):199-203
采用新的微波固相法制备出Mn(Salen)/Al-HMS催化剂.通过FTIR和TG的表征,结果表明,微波固相方法成功地将Mn(Salen)配合物固载于介孔Al-HMS分子筛中.以苯乙烯环氧化反应为例比较了不同方法制备的催化剂的催化性能,发现微波固相法制备的Mn(Salen)/Al-HMS-IP催化剂具有较高的催化活性和最好的环氧化物选择性,此外,考察了催化剂性能还与制备过程中的微波辐射时间、反应时间、反应溶剂、反应温度、氧化剂的用量及催化剂的重复使用对微波固相法制备的催化剂的性能影响规律,得到了满意的结果.  相似文献   

11.
Many biocatalytic reaction systems are biphasic with a reactive and an immiscible non-reactive phase. The reactive, mostly aqueous phase provides a natural enzyme environment and the non-reactive phase serves for delivery of dissolved substrates at high concentrations and for extraction of products. The proper choice of the non-reactive phase will have manifold influence on the catalytic parameters, such as activity, selectivity, and stability, but also on the maximum obtainable conversion or yield.

Conversion or yield constitutes a concise target of practical relevance for rational solvent screening which requires thermodynamic information on coupled reaction and phase equilibria as input information. As long as the reactive phase is kept constant, only the partition equilibrium of each solute in any solvent combination has to be determined. The experimental determination of these data requires a considerable laboratory effort. Therefore, an in-silico screening of solvents for maximal conversion of alcohol dehydrogenase-catalysed oxidoreductions of prochiral ketones was evaluated. COSMO-RS was used for the prediction of solute partitioning between organic solvents and aqueous reaction medium.

Although significant absolute deviations were found, COSMO-RS still predicted the correct trends for the partition coefficients of solutes in different solvents. The calculated overall reaction equilibrium using these partition coefficients again resulted in the prediction of the correct best solvent regarding conversion.  相似文献   


12.
Mn(Salen)/Al-HMS催化剂微波固相法制备及其催化性能   总被引:2,自引:0,他引:2  
采用新的微波固相法制备出Mn(Salen)/Al-HMS催化剂。通过FT IR和TG的表征,结果表明,微波固相方法成功地将Mn(Salen)配合物固载于介孔Al-HMS分子筛中。以苯乙烯环氧化反应为例比较了不同方法制备的催化剂的催化性能,发现微波固相法制备的Mn(Salen)/Al-HMS-IP催化剂具有较高的催化活性和最好的环氧化物选择性,此外,考察了催化剂性能还与制备过程中的微波辐射时间、反应时间、反应溶剂、反应温度、氧化剂的用量及催化剂的重复使用对微波固相法制备的催化剂的性能影响规律,得到了满意的结果。  相似文献   

13.
研究了丙烯环氧化反应条件,系统考察了反应压力、溶剂中水质量分数、TS-1质量分数以及反应温度对过氧化氢转化率以及环氧丙烷选择性的影响,采用非机理速率方程确定了主反应动力学参数。并采用该反应动力学模型对TS-1质量分数、溶剂中水质量分数对在不同温度下的双氧水转化速率常数进行了关联。为今后建立复杂动力学模型以及该工艺的工业化打下了良好的基础。  相似文献   

14.
李颢  曾淼  彭川 《广东化工》2013,(19):11-12,15
以H2O2为氧化剂,Al-TS-1为催化剂催化1-己烯环氧化合成了1,2-环氧己烷。研究了Al含量和溶剂对反应的影响,筛选出较合适的催化剂Al-TS-1(SiO2/Al2O3=616)。采用甲醇为溶剂时,Al-TS-1表现出较低的催化活性和选择性;而采用乙腈为溶剂时,Al-TS-1表现出较高的催化活性和选择性。说明掺杂Al3+后,TS-1的疏水性发生了改变,乙腈溶剂的采用可能改变了反应的历程。  相似文献   

15.
用程序升温还原方法合成了Cu-Ni/γ-Al2O3催化剂,使苯直接羟基化合成苯酚。对该反应过程中,反应温度、反应溶剂、反应原料的不同配比等因素的影响进行了探讨。采用H2-TPR、XRD等技术考察了CuO、NiO的还原状态,确定了最佳还原温度和最佳反应条件:在350℃的还原温度下,当反应温度为70℃、水为反应溶剂、n(H2O)∶n(C6H6)=40∶1、n(H2O2)∶n(C6H6)=5∶1时,苯转化率为36.2%,苯酚选择性为86.3%,苯酚收率为31.2%。  相似文献   

16.
赵红庆  刘奇磊  张磊  董亚超  都健 《化工学报》2021,72(3):1465-1472
药物研制过程存在着大量的液–液均相有机反应,合适的反应溶剂能够大幅提高此类反应的反应速率与选择性,从而提高合成效率,提升药物质量。以2,4-二氯-5-硝基嘧啶与对氨基苯腈的芳香亲核反应(SNAr)为研究对象,采用计算机辅助分子设计(computer-aided molecular design, CAMD)的方法进行反应溶剂设计。首先使用量子力学(quantum mechanics, QM)计算的方法获得少量溶剂中的反应速率常数并通过反应动力学模型与溶剂性质关联,然后构建同时考虑选择性和反应速率常数的混合整数非线性规划(mixed-integer nonlinear programming, MINLP)的多目标优化模型,最后采用分解式算法对模型优化求解,实现制药反应溶剂设计的目标。  相似文献   

17.
本文对聚(异氰脲酸酯一噁唑烷酮)进行了增韧改性研究.端羟丁睛、端羧丁腈液体橡胶和端羟聚醚N220作为增韧剂均取得较好的增韧效果.本文还对其增韧规律以及增韧的主要耗能过程进行了探讨.  相似文献   

18.
以自制PW/SiO_2-Al_2O_3为催化剂,研究载体及其负载量对萘异丙基化反应转化率和选择性的影响,并考察反应时间、活化温度和反应温度对催化剂性能的影响。结果表明,以异丙醇和萘[n(异丙醇)∶n(萘)=2]为原料,环己烷为溶剂,在活化温度和反应温度均为250℃及反应时间5 h条件下,磷钨酸(PW)负载质量分数40%时,PW/SiO_2-Al_2O_3负载型催化剂对萘异丙基化反应的催化效果最好,萘转化率87. 97%,DIPN选择性41. 41%,DIPN中β,β-DIPN占比达到59. 82%。  相似文献   

19.
The chlorination of vulcanized styrene-butadiene rubbers (SBRs) with trichloroisocyanuric acid (TCI) has been studied. The solvent used to apply the TCI chlorinating solutions on the rubber plays an important role in the effectiveness of the treatment since the solvent determined the degree of penetration of TCI into the rubber and also different chlorinating species were produced depending on the nature of the solvent. Surface modifications produced on a synthetic sulfur-vulcanized SBR using TCI solutions in ethyl acetate (EA), methyl ethyl ketone (MEK), and EA + MEK mixtures have been compared. Furthermore, the effects of a solvent wipe with EA or MEK prior to the chlorination process were also considered. Surface modifications produced by the treatments were analyzed using ATR-IR spectroscopy, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). Adhesion was obtained from the T-peel strength of treated rubber/polyurethane adhesive joints. TCI/MEK solutions produced a higher degree of surface modification than TCI/EA solutions, but TCI/EA solutions were more effective in removing zinc stearate from the rubber surface. When high TCI percentages (5-7 wt%) in EA solutions were used, a weak boundary layer (WBL) was created on the rubber surface as a consequence of the deposition of an excess of chlorinating agent on the rubber surface and of by-products (cyanuric and/or isocyanuric acid). The formation of the WBL led to a lack of adhesion in the rubber towards the polyurethane adhesive. When MEK was used as a solvent for TCI, this WBL was not produced on the rubber surface, and thus adhesion was considerably higher even when high concentrations of TCI/MEK were used. Similar effects were produced using EA + MEK mixtures as the solvent for TCI. The wiping of the rubber surface with MEK prior to the chlorination treatment led to good adhesion, irrespective of the percentage of TCI and the solvent used in the chlorinating solution.  相似文献   

20.
通过静态试验,筛选出适宜于高炉净环水系统的杀菌剂—氧化型有机氯化物优氯净。结果表明,该杀菌剂在碱性条件下,对异养菌、铁细菌和硫酸盐还原菌都具有很高的杀菌率。文中还对其杀菌机理作了探讨。  相似文献   

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