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采用溶胶-凝胶法制备了二氧化硅负载磷钼钒酸铯催化剂,利用XRD、红外、SEM以及物理吸附等技术手段对催化剂进行了表征分析,并以稀硝酸(30%)为硝化剂,考察了该催化剂对苯酚硝化反应的催化性能,系统研究了反应时间、催化剂用量、硝酸与苯酚用量以及催化剂重复利用等对催化反应的影响。 结果表明,制备的负载磷钼钒酸铯催化剂具有典型的Keggin结构,在温和的苯酚硝化反应条件下,表现出优良的催化活性和高的邻硝基苯酚选择性,在实验优化条件下,邻硝基苯酚收率达到88%,催化剂回收方便可多次重复使用。 负载磷钼钒酸铯催化苯酚硝化反应结合水蒸汽蒸馏提供了一种简单可行的制备邻硝基苯酚的方法。 相似文献
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一硝基氯苯的区域选择性合成研究(Ⅰ)硝酸硝化 总被引:3,自引:1,他引:3
制备了SO2-4/TiO2、SO2-4/ZrO2和一系列钛锆原子比不同的SO2-4/TiO2-ZrO2固体酸催化剂,并通过XRD、FTIR和TG-DTA等进行了表征;研究了这些催化剂上硝酸硝化氯苯的区域选择性. 结果表明,在醋酐存在下,氯苯与等物质量的硝酸反应,其产物具有强对位选择性,在SO2-4/TiO2-ZrO2(原子比1∶2)催化剂上,氯苯一硝化产物中邻/对硝基氯苯异构体的质量比达0.29,较硝硫混酸硝化的0.57显著降低,产物得率可达70.2%. 该反应快速且催化剂可循环使用. 相似文献
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邻氯甲苯混酸硝化合成6-氯-3-氨基甲苯-4-磺酸(CLT酸)因其产率低及选择性差而未能实现工业生产,本文对该工艺进行了改进,采用酸性β沸石和乙酰硝酸酯作为催化剂和硝化剂,提高了硝化选择性和收率,分别为72%和97%;并改进了还原、异构体分离和磺化操作;CLT酸总收率提高到61%. 相似文献
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一硝基氯苯的区域选择性合成研究 总被引:5,自引:0,他引:5
制备了SO4^2-/TiO2、SO4^-/ZrO2和一系列钛锆原子比不同的SO4^2-/TiO2-ZrO2固体酸催化剂,并通过XRD、FTIR和TG-DTA等进行了表征;研究了这些催化剂上硝酸硝化氯苯的区域选择性。结果表明,在醋酐存在下,氯苯与等物质量的硝酸反应,其产物具有强位选择性,在SO4^2-/TiO2-ZrO2(原子比1:2)催化剂上,氯苯一硝化产物中邻/对硝基氯苯异构体的质量比达0.29,较硝友混酸消化的0.57显著降低,产物得率可达70.2%,该反应快速且催化剂可循环使用。 相似文献
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芳香族硝基化合物是一类重要的化学原料和有机合成中间体.传统的亲电硝化反应难以做到区域选择性地定位硝化.近几十年来,过渡金属催化的C—H键活化反应得到了快速发展,目前大多数官能团都可以通过过渡金属与导向基团的螯合作用引入芳烃的特定位置.钯、钌及铑等过渡金属催化的导向基团辅助芳烃C—H键硝化反应研究副产物较少,具有很好的区域选择性,更加绿色环保,已经取得了重要的进展.根据不同的过渡金属催化剂进行分类,综述了导向基团辅助的惰性C—H键硝化反应研究进展,对该研究领域的局限性和未来的发展前景进行总结和展望. 相似文献
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芳香族化合物的硝化反应是工业生产中重要的单元反应,钝化芳环的硝化反应在医药、农药、染料和炸药合成中有重要地位。本文从硝化试剂角度综述了近年来钝化芳环的硝化反应的进展,包括硝酸盐/硫酸、硝酸酯、硝酸、氮氧化物等硝化方法。简要评述了这些方法的特点,并展望了硝化方法的研究方向。其中,硝酸盐/硫酸体系具有较强的硝化能力,对于钝化芳环,可以在温和条件下以高收率得到硝化产物,在实验室制备或工业应用中具有较高的应用价值;其他硝化方法由于各种原因暂时不能对钝化程度较高的芳环进行硝化,还需进一步研究具有较高活性的硝化体系。 相似文献
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When treated with nitrogen dioxide in the presence of ozone and a catalytic amount of iron(III) chloride in inert organic solvent at -10 to +5 degrees C, benzenedicarboxylic acid diesters 1, 4, and 6 underwent smooth nitration to give the corresponding mononitro derivatives 2/3, 5, and 7, respectively, in good yield (kyodai nitration). Naphthalenecarboxylic acid esters 8 and 11 and naphthalene-1,8-dicarboxylic acid diester 16 were similarly nitrated in the absence of catalyst to give the expected nitro compounds 9/10, 12-15, and 17-22, respectively. Different from conventional nitration based on the combined use of concentrated nitric and sulfuric acids, no hydrolytic cleavage of the ester function was observed under these conditions. The isomer distribution has been determined for the nitration of naphthalenecarboxylic acid esters 8, 11, and 16, and spectral data were collected for less common nitro derivatives. A unique changeover of the orientation mode observed in the kyodai nitration of diester 16, from the initial exclusive meta to the final meta/para, has been discussed in terms of the competition between the electrophilic substitution process involving the nitronium ion (NO2+) and the addition-elimination sequence involving the nitrogen trioxide radical (*NO3). 相似文献
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G. A. Golubeva Yu. N. Portnov A. N. Kost L. I. Borisova A. K. Trukhmanov 《Chemistry of Heterocyclic Compounds》1978,14(10):1119-1122
Bromination, nitration, and sulfonation reactions in the acylphenylpyrazolidine series were investigated. 1-(p-Bromophenyl)-2-acylpyrazolidines are formed in good yields in the bromination of these compounds over a wide range of temperatures in various solvents. Removal of the acyl group takes place simultaneously with sulfonation in the para position of the phenyl ring in the sulfonation of phenylacylpyrazolidines with concentrated sulfuric acid at room temperature; the p-sulfophenylpyrazolidines formed in this case exist in the form of betain structures. The nitration of acylphenylpyrazolidines with concentrated nitric acid (sp. gr. 1.52) leads to 1-(2,4-dinitrophenyl)-2-acylpyrazolidines. However, the nitration of these compounds with dilute nitric acid (sp. gr. 1.35) is accompanied by pronounced resinification; both 2,4-dinitrophenyl and p-nitrophenyl-2-acylpyrazolidines, as well as dimers of the latter, were detected among the reaction products.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1377–1380, October, 1978. 相似文献
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The reactivities of benzylphosphonic acid (protonated and unprotonated) and β-phenylethylphosphonic acid have been determined for nitration. The highly selective para/ortho orientation has been confirmed. The relative reactivities of systems PhX and PhCH2X for some substituents are discussed. 相似文献
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Yu. V. Strokin I. A. Krasovskii A. K. Sheinkman N. A. Klyuev R. I. Sinitsyna 《Chemistry of Heterocyclic Compounds》1981,17(9):950-953
The chemical transformations of 2- and 3-substituted thiazolo[3,2-f]xanthines with electrophilic reagents were studied, and it was established that the 2 position of the thiazole ring is active in bromination, while the para position of the aryl substituent is active in nitration. The structures of the substances obtained were established from the IR, PMR, and mass-spectral data.See [1] for Communication 3.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1267–1271, September, 1981. 相似文献
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L. D. Smirnov V. S. Zhuravlev V. P. Lezina K. M. Dyumaev 《Chemistry of Heterocyclic Compounds》1974,10(8):951-952
The nitration of 2- and 5-benzyl-3-hydroxpyridines and their N-oxides takes place in the para position of the phenyl ring. The introduction of an N-oxide group into the Β-pyridol ring does not affect the orientation of substitution. 相似文献
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K. M. Dyumaev E. P. Popova I. F. Mikhailova L. I. Shibaeva L. D. Smirnov 《Chemistry of Heterocyclic Compounds》1974,10(6):699-701
The nitration of 3-hydroxyquinoline with concentrated nitric acid in sulfuric acid at ?30 to +30°C gives 5-nitro-3-hydroxyquinoline (85–92%) and 7-nitro-3-hydroxyquinoline (7–12%). 4-Nitro-3-hydroxyquinoline is formed in 70% yield by nitration in acetic acid. 4,5-Dinitro-3-hydroxyquinoline is formed by further nitration of 4- and 5-nitro-3-hydroxyquinolines. 相似文献
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Yang Anming Yue Jincai Zheng Shiqing Yang Xia Kong Lingqi Zhou Dongjian Qin Litao Zhong Hua 《Research on Chemical Intermediates》2022,48(10):4373-4390
Research on Chemical Intermediates - Mononitrotoluene is an important dye intermediate, which is prepared by nitration of toluene and mixed acid. The nitration of toluene with mixed acid is a fast... 相似文献
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A. O. Finogenov M. A. Epishina I. V. Ovchinnikov A. S. Kulikov I. V. Anan’ev N. N. Makhova 《Russian Chemical Bulletin》2011,60(2):339-344
Isomeric 1,3- and 1,4-bis[3(4)-nitrofuroxan-4(3)-yl]nitro(dinitro)benzenes were synthe-sized in high yields by nitration of
the corresponding 1,3- and 1,4-bis[3(4)-nitrofuroxan-4(3)-yl]benzenes with a mixture of 100% nitric acid and concentrated
sulfuric acid. The influence of 3- and 4-nitrofuroxanyl fragments on the regioselectivity of the nitration was revealed. The
structure of 1,3-bis(4-nitrofuroxan-3-yl)-4-nitrobenzene was confirmed by X-ray diffraction analysis. 1,3- and 1,4-Bis(3-nitrofuroxan-4-yl)nitrobenzenes
underwent thermal isomerization to more thermodynamically favorable 1,3- and 1,4-bis(4-nitrofuroxan-3-yl)nitrobenzenes. 相似文献
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N. S. Prostakov A. P. Krapivko A. T. Soldatenkov K. Furnaris A. A. Savina V. P. Zvolinskii 《Chemistry of Heterocyclic Compounds》1976,12(3):312-315
2,5-Dimethyl-4-phenylpyridine is nitrated in the para position of the phenyl ring. Further nitration of the resulting nitro compound gives a mixture of isomeric dinitro derivatives. In the case of 4-phenylisocinchomeronic acid the nitro group enters the meta position of the phenyl ring.Translated from Khimiya Geterotsiklicheskikh Soedinenii. No. 3, pp. 365–368, March, 1976. 相似文献