Nitration anodique

Anodic oxidation of aromatic hydrocarbons and olefins in acetonitrile containing silver nitrite, has been studied.With aromatic hydrocarbons the better yields in mononitro compounds were obtained with anthracene and methoxybenzene. The orientation is discussed: the site of substitution is the unsubstituted position with most important spin density in the radical cation (from substrate oxidation).Diphenyl ethylene and paramethoxystyrene yields nitroolefins; the 2-phenylpropene produce a mixture of nitroolefin and nitro alcohol. Trans stilbene gave a mixture of 1,2 addition products containing the nitrato group. In order to explain the formation of the products we proposed a mechanism consistent with the ambidentate character of the nitrite ion.     

Probing Tyrosine Nitration with a Small TbIII-Metallopeptide

Tyrosine nitration, a post-translational modification (PTM) that takes place under nitrosative stress conditions, occurs through a non-enzymatic peroxynitrite-mediated reaction. Although protein nitration has long been considered an irreversible PTM involved in nitrosative stress-associated diseases, it has also been suggested to be a regulatory mechanism of signal transduction. Therefore, the development of tools that help to understand this protein modification is of great interest. Herein, we explore a Tb^III-chelating metallopeptide to monitor tyrosine nitration. The luminescence of this probe decreases significantly between its non-nitrated and nitrated states, and this reduction in the luminescence intensity is directly related to the degree of tyrosine nitration after treatment with peroxynitrite. Remarkably, the luminescence intensity changes after nitration are not affected in the presence of complex biological media, which makes it a promising tool for understanding this protein modification.     

Specifics of Silicon Nitration

The sequence of formation of silicon nitride phases inside the volume of an initial silicon grain heated in a gaseous nitrogen medium is studied. Technologies for making ceramics articles based on silicon nitride are proposed.     

4-氯喹啉的硝化

研究了4-氯喹啉的5-位和8-位的硝化反应。利用发烟硝酸和浓硫酸的混酸体系,在4-氯喹啉的5-位或者8-位引入1个硝基,从而方便地合成8-硝基-4-氯喹啉和5-硝基-4-氯喹啉。反应总收率达75%以上。在该反应中,不同的投料顺序可以影响8-硝基-4-氯喹啉和5-硝基-4-氯喹啉的产出比例。以4-氯喹啉缓慢加入混酸体系的投料方式,有助于提高5-硝基-4-氯喹啉的收率。     

钝化芳环的硝化反应

研究了一系列含有不同钝化基团的芳环化合物的硝化方法,考察了三氟甲基苯、对苯二甲酸二甲酯和对苯二甲酸用混酸直接硝化,收率分别为82．6％、79．8％和92．8％。对影响反应的因素,如硫酸的浓度和用量、反应温度和不同钝化基团的影响等进行了分析。     

氯苯清洁硝化

硝基氯苯是重要的化工原料,广泛用于精细化学品的合成.传统硝硫混酸硝化工艺存在副反应多、设备腐蚀、环境污染等缺陷.文章综述固体酸、离子液体、稀土盐/氟两相、氮氧化物、微反应器应用于氯苯硝化研究的最新进展,展望其发展方向.     

3-氟甲苯的硝化反应

以3-氟甲苯为原料，用三种不同硝化反应制备了5-氟-2-硝基甲苯。采用混酸硝化(在溶剂中，36.2ml浓硝酸、14.8ml浓硫酸、0℃～5℃、90g3-氟甲苯)，5-氟-2-硝基甲苯的选择性为59.8％；68%，的浓硝酸／多聚磷酸硝化(28.0ml 68％硝酸、0℃～5℃、35g多聚磷酸、16．5g3-氟甲苯)5-氟-2-硝基甲苯的选择性为80.0％；浓硝酸硝化(96.5ml浓硝酸、200g3-氟甲苯、50℃～55℃、8小时、真空蒸馏)5-氟-2-硝基甲苯的选择性为79.9％，应用H-MR和IR对产品进行了表征。     

Demethylation and Nitration of Lignin

Abstract

The formation of methanol during treatment of wood meal with nitrogen dioxide is favored by the presence of oxygen and suppressed by addition of sodium sulfate. With 0.5% of added nitrogen dioxide large amounts of methanol were produced at 70°C when kraft lignin was impregnated with 0.5M nitric acid. A markedly increased formation of methanol and nitro groups in the lignin occurred when sodium nitrate was added. At low acidity the effect of sodium nitrate was insignificant. In a solution which was 0.5 molal with respect to nitric acid and 0.8 molal with respect to sodium nitrate, appreciable amounts of methanol and nitro groups were produced even when no nitrogen dioxide was added. This is explained by a generation of nitrogen dioxide from nitric acid in a autocatalytic process favored by high concentrations of nitrate and hydrogen ions.     

Nitration of the Acetanilide-type Compounds

Some aromatic compounds containing the imino group (NH) were nitrated in acetic acid or anhydride, and the ortho/para ratios were measured. N-Methyl derivatives of the aforementioned compounds are much less reactive when nitrated under comparable conditions and give significantly lower o/p ratios. These results along with the literature data support the hypothesis that the acetanilide-type compounds are nitrated via N-nitro intermediates.     

反式-9,10-二氢-9,10-二对甲苯基-9,10-菲二醇包结性能的研究

合成了主体分子反式-9,10-二氢-9,10-二对甲苯基-9,10-菲二醇(1),它可以和苯、喹啉形成晶体包结物,通过m.p.、IR、粉末XRD对它们进行了表征,通过^1HNMR积分计算包结物主客体物质的量比分别为：n1：n苯=3：2;n1：n喹啉=1：1。     

绿色硝化反应研究进展

介绍了磺酸镧系盐催化硝化、氮氧化物硝化、固体酸催化硝化、液相负载硝化和气相硝化等绿色硝化反应,评述了它们的优缺点,提出了固体氧化物和全氟烷磺酸协同催化NO2／O2绿色硝化反应,有望成为一种有前途的绿色硝化方法。     

9,10-二羟基环十六内酯的合成

紫胶桐酸是一种具有生物活性的长链羟基烷酸,可用于大环内酯的合成。以紫胶桐酸多羟基作为起始原料,利用高度稀释的合成策略,通过缩醛选择性保护邻二醇、直链前体内酯化环合及酸催化环缩醛脱保护三步反应制备得到了目标产物9,10-二羟基-环十六内酯,总收率为31%,所得产物经红外光谱(IR)、核磁共振氢谱和碳谱(1 H NMR和13C NMR)、电喷雾质谱(ESI-MS)表征得以证实。实验均在室温下进行,反应条件温和,简洁有效。     

新型螺旋盘管反应器硝化工艺研究

硝化反应大多为快速强放热反应,要求硝化反应器应同时具备优良的混合和传热性能。采用新型螺旋盘管反应器并以混酸硝化苯作为工作体系进行了硝化工艺研究,考察了循环流量、混酸流量、混酸组成、反应温度等因素对苯转化率和硝化反应选择性的影响规律,并与螺旋盘管直径和长度相同的直管硝化工艺进行了对比研究。结果表明,在实验考察范围内,反应温度或物料循环流量提高时,硝基苯的选择性提高,但苯的转化率有所降低。增大混酸流量或混酸中硫酸摩尔比时,可提高苯的转化率,但由于增大了酸局部过量的几率,副产物亦随之增加。与直径和长度相同的直管相比,螺旋盘管反应器硝化过程中苯的转化率和硝基苯的选择性均有所提高。     

绿色硝化剂五氧化二氮对甲苯的硝化研究

研究了在HZSM-5分子筛催化下,五氧化二氮对甲苯的硝化反应。该方法通过改变硝化剂,不仅成功地避免了浓硫酸的使用,而且提高了原子经济性,具有良好的环境效益。实验考察了反应温度、反应时间,催化剂用量及Si/Al对反应结果的影响。研究表明,在最佳反应条件下,甲苯硝化反应得率达到42%,对位选择性为79%。     

绿色硝化研究进展

叙述了绿色硝化目前现状,指出新技术如氟两相、微波及超声波应用在硝化反应中的重要作用,特别指出N2O5-离子液体体系在硝化反应中的应用,尤其是在胺类硝化中,对促进硝化反应绿色化有重要意义.附参考文献71篇.     

气相硝化制备硝基烷烃

介绍了硝基烷烃气相硝化的发展历程。综述了低碳烷烃、脂肪醇、羧酸、醛和酮类均相气相硝化制备方法。并对最新的高压硝化法制备硝基烷烃进行了简介。随着气相硝化技术的不断发展,硝基烷烃将得到更为广泛的应用。     

4-乙酰氨基苯甲醚的硝酸盐选择性硝化

研究了4-乙酰氨基苯甲醚选择性硝化反应.研究发现有机溶剂中硝酸盐硝化4-乙酰氨基苯甲醚,硝化产物主要为3-硝基-4-乙酰氨基苯甲醚.而传统的硝硫混酸硝化方法,硝化产物主要产品是2-硝基-4-乙酰氨基苯甲醚.     

Nitration of Condensed Polycyclic Aromatic Ketones

Nitration of three isomeric dibenzanthrones, 13H-dibenzo[a,de]-anthracene-13-one(3), 7H-benzo[hi]chrysene-7-one(4), and 7H-dibenzo[a,kl]anthracene-7-one(5), with concentrated nitric acid was studied under various conditions. The nitration of (3) at 15 °C in 1,1,2,2-tetrachloroethane gave the 5-nitro derivative. The nitration of (4) in boiling acetic acid produced the 9-nitro derivative. The nitration of (5) at 70 °C in acetic acid gave the 5-nitro derivative. These nitro compounds are very useful in synthesizing undecacyclic aromatic hydrocarbons.