4-溴-5-甲基靛红的Baeyer-Villiger氧化产物的波谱分析

４－溴－５－甲基靛红分别与单过邻苯二甲酸，过硫酸钾－硫酸两种氧化剂发生Ｂａｅｙｅｒ－Ｖｉｌｉｇｅｒ反应，生成两种同分异构体：５－溴－６－甲基－１Ｈ－苯并［１，３］嗪－２，４－二酮和新化合物５－溴－６－甲基－１Ｈ－苯并［１，４］嗪－２，３－二酮。利用ＭＳ、１３ＣＮＭＲ、１ＨＮＭＲ、ＩＲ对产品结构进行了分析鉴定。     

溴代靛红异构体含量的同时测定

采用紫外二阶导数分光光度法测定常山酮合成工艺中同分异构体6-溴靛红和4-溴靛红的含量。4-溴靛红测定的线性范围2～80mg/L,相对标准偏差0．178％,回收率99．9％～100．1％;6-溴靛红测定的线性范围2～60mg/L,相对标准偏差0．091％,回收率98．7％～100.1％。该法简便、快捷、准确、灵敏。     

4—溴—5—甲基靛红的Baeyer—Villiger氧化物的波谱分析

４－溴－５－甲基靛红分别与单过邻苯二甲酸，过硫酸钾－硫酸两种氧化剂发生Ｂａｅｙｅｒ－Ｖｉｌｌｉｇｅｒ反应，生成两种同分异构体：５－溴－６－甲基－１Ｈ－苯并［１，３］恶嗪－２，４－二酮和新化合物５－溴－６－甲基－１Ｈ－苯并［１，４］恶嗪－２，３－二酮。利用ＭＳ、＾１３ＣＮＭＲ、＾１ＨＮＭＲ、ＩＲ反应，单过邻苯二甲醇，ＩＲ对产品结构进行了分析鉴定。     

2-溴-4-甲基苯酚的合成

2-溴-4-甲基苯酚是合成许多药物及广谱型香料香兰素的重要中间体。常温下,以对甲基苯酚为原料加溴易生成2,6-二溴-4-甲基苯酚,本文在原来工作的基础上,在低温下,通过溴化氧化一步直接合成了2-溴-4-甲基苯酚,产率可达93％并通过红外光谱和核磁共振谱对产物结构进行确证。反应的最佳条件是：反应温度为-5～-10℃,反应时间为4h,搅拌速度为1000r／min,对甲基苯酚与双氧水物质的量比为1：0．85。反应方程式如下：     

2-乙氧羰基-3-溴-4-甲基-5-甲酰基-吡咯的合成

2-乙氧羰基-3-溴-4-甲基-5-甲酰基-吡咯的合成;乙氧羰基二甲基吡咯;乙氧羰基溴二甲基吡咯;乙氧羰基溴甲基甲酰基吡咯     

2-甲基-4-羟基-6-苯基嘧啶和2-甲基-4-羟基-5-溴-6-苯基嘧啶的高效液相色谱法分离测定

采用ODS-C18色谱柱和紫外检测器,对2-甲基-4-羟基-6-苯基嘧啶和2-甲基-4-羟基-5-溴-6-苯基嘧啶的含量进行HPLC分离测定.以甲醇水=4555为流动相,紫外检测波长为237 nm,样品线性范围为0.001～0.1 mg/mL.2-甲基-4-羟基-6-苯基嘧啶的RSD为0.5%;2-甲基-4-羟基-5-溴-6-苯基嘧啶的RSD为1.0%.     

Baeyer-Villiger氧化反应的不同催化体系

Baeyer-Villiger氧化反应能控制产物的立体化学结构,在有机合成中对功能基转化和环扩张有重要的意义,因此氧化所得的产物可以广泛应用于合成许多天然产物和药物中间体以及一些高分子材料的单体等,是目前有机化学研究的热点之一。随着对该反应研究的深入,其催化剂的类型也在不断地增多,包括均相催化剂、非均相催化剂、生物催化剂。均相催化剂选择性和转化率虽高,但不及非均相催化剂重复利用率高。生物催化剂绿色环保,是未来研究的重点之一。本文从均相催化、非均相催化和生物催化三个方面对Baeyer-Villiger氧化反应相关的研究新进展进行了阐述,重点介绍了不同催化体系下催化剂与反应底物之间的作用,总结了有关催化反应的机理,并对Baeyer-Villiger氧化反应的发展进行了展望。     

2 ,2-二取代-1,3-环戊二酮的Baeyer-Villiger氧化反应

研究了 2 ,2 -二取代 - 1 ,3-环戊二酮的Baeyer_Villiger氧化反应 ,合成了 4个新的 5,5-二取代 - 4-氧代 -δ -内酯 ,它们的结构通过IR、1 HNMR和元素分析予以确定。     

Synthesis of Heterocyclic Systems on the Basis of 4-Bromo-5-nitrophthalonitrile

Reaction of 4-bromo-5-nitrophthalonitrile with aromatic and heterocyclic N- and O-nucleophiles in the presence of bases leads to the sequential substitution of the bromine atom and the nitro group to give the corresponding heterocyclic systems previously undescribed in the literature.     

微乳液的增敏作用研究—5－Br－PADAP分光光度测定锰（Ⅱ）

以含水量８０％的Ｏ／Ｗ型ＳＤＳ／正丁醇／正庚烷／水微乳液为介质，以５－Ｂｒ－ＰＡＤＡＰ为显色剂，分光光度测定Ｍｎ（Ⅱ）．表观摩尔吸光系数ε５７０＝１．０８×１０５Ｌ·ｍｏｌ－１·ｃｍ－１，与相同含水量的ＳＤＳ胶束体系相比，测定灵敏度有显著提高，改善了实验条件．方法用于铝合金和茶叶中Ｍｎ（Ⅱ）的测定，结果令人满意     

三价碘试剂促进的氧化反应研究进展

三价碘试剂的反应性能类似于过渡金属如汞、钛和铅,并且具有环境友好、价值低廉、反应条件温和、反应后处理简单和商业可利用的特点,因此在有机合成中得到广泛应用,特别是作为一种高效的选择性氧化试剂,受到广大有机化学工作者的亲睐。本文就三价碘试剂促进的氧化反应,从醇的氧化、羰基化合物的氧化官能团化到氧化硒化和铋化等14类反应进行了简单的综述。     

混合微乳液的增敏作用研究：Cd（Ⅱ）—5—Br—PADAP的分光光度测定

研究了在Ｏ／Ｗ混合微乳液ＳＤＳ－ＯＰ／ｎＣ４Ｈ９ＯＨ／ｎ－Ｃ７Ｈ１６／Ｈ２Ｏ介质中，Ｃｄ（Ⅱ）－５－Ｂｒ－ＰＡＤＡＰ的显色反应。结果表明显色反应的灵敏度较单一的ＳＤＳ微乳液，单一的ＯＰ的微乳液，混合ＳＤＳ－ＯＰ胶束的介质中，具有更好的增敏作用和稳定性，Ｃｄ浓度在０－５μｇ／１００ｍＬ范围内符合比尔定律。方法用于废水和环境水样中微量Ｃｄ的测定，结果满意。     

Stepwise Oxidation of Ketene Dithioacetal

Ketene dithioacetals1-2 have demonstrated their potential for the synthesis of heterocycles, therefore, their synthesis and reactions have attracted much attention. The chemo- and stereo-selective conjugate addition of amine, organocuprate and Grignard reagent with ketene dithioacetal is well documented3-5, and we chose to examine whether the conjugate addition of the phosphite to the ketene dithioacetal occurs to afford the corresponding phosphonyl/S-methyl a-cyano(oxo, ethoxycarbonyl etc.) …     

CoMn@NC催化5-羟甲基糠醛常压氧化为2, 5-呋喃二甲酸二甲酯

2, 5-呋喃二甲酸二甲酯(DMFDCA)这一生物质衍生的增值化学品是石油基聚合物单体对苯二甲酸(TPA)的理想替代品。本研究采用一步共热解法合成了两种廉价金属修饰的氮掺杂多孔碳催化剂CoMn@NC,并将其用于5-羟甲基糠醛(HMF)在温和条件下的需氧氧化。由Co₃Mn₂@NC-800催化HMF在50 ℃和常压氧气的条件下反应12 h后,得到产率为85%的DMFDCA。多孔催化剂的高比表面积提高了传质效率。Co纳米粒子(NPs)和呈原子级分散的Mn与掺杂在碳中的氮配位形成M―N_x。富含吡啶氮的碳基体中的缺电子金属位点有利于HMF和氧的活化。氧形成的超氧自由基阴离子的存在确保了半缩醛中间体和5-(羟基甲基)-2-糠酸甲酯(HMMF)的羟甲基的脱氢氧化,从而高选择性得到DMFDCA。该催化剂性能稳定,可适用于各种取代芳醇。该催化体系具有用于生产聚合物单体羧基酯的应用潜力。     

CoMn@NC催化5-羟甲基糠醛常压氧化为2, 5-呋喃二甲酸二甲酯

Dimethyl furan-2, 5-dicarboxylate (DMFDCA) is a valuable biomass-derived chemical that is an ideal alternative to fossil-derived terephthalic acid as a monomer for polymers. The one-step oxidation of 5-hydroxymethylfurfural (HMF) to DMFDCA is of practical significance. It not only shortens the reaction pathway but also avoids the separation process of intermediates; thus, reducing cost. In this work, non-noble bimetallic catalysts supported on N-doped porous carbon (CoMn@NC) were synthesized via a one-step co-pyrolysis procedure using different pyrolysis temperatures and proportions of metal precursors and additives. We employed the prepared CoMn@NC catalysts in the aerobic oxidation of HMF under mild reaction conditions to obtain DMFDCA. High-yield DMFDCA was obtained by screening the prepared catalysts and optimizing the reaction conditions, including the strength and amount of the base, as well as the reaction temperature. The optimized yield of DMFDCA was 85% over the Co₃Mn₂@NC-800 catalyst after 12 h at 50 ℃ using ambient-pressure oxygen. The physicochemical properties of the catalysts were determined using a variety of characterization techniques, the factors affecting the performance of each catalyst were investigated, and the relationship between the physicochemical properties and performance of the prepared catalysts was elucidated. A porous structure with a high surface area had a positive effect on mass transfer efficiency. Cobalt nanoparticles (NPs) and atomically dispersed Mn were coordinated to N-doped carbon to form M―N_x (where M = Co or Mn). Based on the Mott-Schottky effect, there was significant electron transfer between each metal and the N-doped carbon, additionally, the metal NPs supplied electrons to the carbon atoms. The electron-deficient metal site in the pyridinic N-rich carbon was beneficial for the activation of HMF and oxygen. The activation of oxygen produced reactive oxygen species (such as superoxide radical anions) to ensure high selectivity to DMFDCA through dehydrogenative oxidation of the hemiacetal intermediate and hydroxymethyl group of 5-hydroxymethyl-2-methyl-furoate. The existence of disordered and defective carbons increased the number of active sites. Subsequently, we performed a series of control experiments. Based on our current experimental results and previous studies, we propose a simple mechanism for the aerobic oxidation of HMF to DMFDCA. The catalyst was stable, its performance decreased slightly after two cycles, and it was tolerant to SCN⁻ ions and resistant against N or S poisoning. Furthermore, the use of this catalytic system can be expanded to various substituted aromatic alcohols, such as benzyl alcohols with different substituents, furfuryl alcohol, and heterocyclic alcohols. Simultaneously, the product type was further extended from methyl esters to ethyl esters with a high yield when the substrate reacted with ethanol. In conclusion, this catalytic system can be applied in the production of carboxylic esters for polymers.     

四氯化钛气固相反应法制备钛硅分子筛机理的研究

采用气固相法使TiCl₄与HZSM-5高硅分子筛反应制备了钛硅分子筛Ti-ZSM-5.运用FT-IR, UV-vis, XRD, TG, ICP-AES等手段对合成的钛硅分子筛进行了表征,并以30%H₂O2水溶液环氧化氯丙烯为探针反应对合成的Ti-ZSM-5进行了催化活性考察,结果表明分子筛所载钛原子完全进入骨架,没有发现非骨架钛,Ti-ZSM-5催化性能良好. 定量分析结果表明,钛原子同晶取代铝原子反应进入骨架的贡献极小,仅占骨架钛的0.32%,钛原子主要通过TiCl₄与羟基窝反应而进入分子筛骨架.     

Oxidation of cycloalkanones with hydrogen peroxide: an alternative route to the Baeyer-Villiger reaction. Synthesis of dicarboxylic acid esters

The acid-catalyzed oxidation of cycloalkanones C₅-C₈ and C₁₂ with hydrogen peroxide in alcohols was performed, and dicarboxylic acid esters were obtained as the major products in 53-70% yields. In the first step, geminal bishydroperoxides are generated from five-to-seven-membered cyclic ketones. The Baeyer-Villiger reaction is a side process accompanied by the formation of ω-hydroxycarboxylic acid esters.