Solid supported Pd(0): an efficient recyclable heterogeneous catalyst for chemoselective reduction of nitroarenes

Solid supported palladium(0) (SS-Pd) catalyzed highly chemoselective reduction of nitroarenes to the corresponding anilines was accomplished under a milder reaction condition. This catalyst showed high compatibility with various reducing agents (NaBH₄, Et₃SiH, and NH₂NH₂·H₂O) and a large number of reducible functional groups such as sulfonamide, amides, carboxylic acid, ester, alcohol, halide, hetero cycle, nitrile, alkene, carbonyl, O-benzyl, and N-benzyl were tolerated. Most of the reactions were clean and high yielding. The SS-Pd catalyst could be recycled up to seven runs without significant loss of activity.     

催化光度法测定煤矸石中痕量锡

在浓度为０．０５ｍｏｌ／Ｌ的Ｈ３ＰＯ４介质中,痕量锡对ＮａＨ２ＰＯ２还原罗彤明Ｂ９ＲｈＢ）褪色反应有催化作用,褪色速度ｎ含量线性相关,建立了催化吸光光度法测定痕量Ｓｎ的方法。褪色反应随温度同而加快在沸水浴中５ｍｉｎ,△Ａ可达最大值,流水冷却后吸光度保持１２ｈ基本不变,溶液的最大吸收波长为５５５ｎｍ。方法检出限为０．０３５μｇ／Ｌ,吸光度变化ｎ的质量浓度在０～１．０μｇ／５０ｍＬ范围内符合比耳定律。     

Influence of Freeze-Dried Phenolic-Rich Plant Powders on the Bioactive Compounds Profile,Antioxidant Activity and Aroma of Different Types of Chocolates

In this study, the blueberries (BLUB), raspberries (RASB), blackberries (BLCB), pomegranates pomace (POME) and beetroots (BEET) freeze-dried powders were used as the sources of phenolic compounds to enrich different types of chocolates, substituting a part of the sweetener. It was found that 1% addition of fruit or vegetable powders to chocolates increased the content of total phenolic compounds (flavan-3-ols, phenolic acids and anthocyanins) of enriched dark and milk chocolates compared to the control ones dependent on the powder used. Among the enriched chocolates, the chocolates with the addition of BLUB powder were characterized by the highest total polyphenol content. The highest percentage increase (approximately 80%) in the total polyphenol content was observed in MCH chocolate enriched with BLUB powder. Chocolates incorporated with BLUB, RASB, BLCB and POME powders presented a richer phenolic compound profile than control counterparts. The highest DPPH radical-scavenging capacity was exhibited by the DCH98S chocolate enriched with BEET powder. However, the DCH98ESt chocolates enriched with POME and BEET powders demonstrated the highest FRAP values. An electronic nose analysis confirmed the existence of differences between the profiles of volatile compounds of various types of chocolates enriched with fruit or vegetable powders. Thus, the enrichment of dark and milk chocolates with BLUB, RASB, BLCB, POME and BEET powders seemed to be an interesting approach to enhance bioactivity and to enrich the sensory features of various chocolate types.     

Coffee Beverage: A New Strategy for the Synthesis of Polymethacrylates via ATRP

Coffee, the most popular beverage in the 21st century society, was tested as a reaction environment for activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP) without an additional reducing agent. Two blends were selected: pure Arabica beans and a proportional blend of Arabica and Robusta beans. The use of the solution received from the mixture with Robusta obtained a high molecular weight polymer product in a short time while maintaining a controlled structure of the synthesized product. Various monomers with hydrophilic characteristics, i.e., 2-(dimethylamino)ethyl methacrylate (DMAEMA), oligo(ethylene glycol) methyl ether methacrylate (OEGMA₅₀₀), and glycidyl methacrylate (GMA), were polymerized. The proposed concept was carried out at different concentrations of coffee grounds, followed by the determination of the molar concentration of caffeine in applied beverages using DPV and HPLC techniques.     

Chitosan-supported Borohydride Reducing Agent

Borohydride exchange resin (BER) a useful reducing reagent has been used in reduction of some carbonyl compounds and acyl halides1. When BER combines with a transition metal catalyst, it can reduce C=C double bonds2, halides2, nitro compounds3, cyano, diazo3 and azide compounds4. The support of BER is the synthetic macromolecule polystyrene. Here, we used chitosan as the support of borohydride. As known, chitosan is a renewable and abundant natural polysaccharide. Scheme 1 Preparat…     

降铅Ⅰ号冲剂防治儿童铅中毒的研究附100例临床疗效观察

观察了用降铅I号冲剂防治儿童铅中毒100例临床疗效,治疗组降铅疗效明显好于对照组。     

5种还原糖与南极磷虾粉酶解液美拉德反应产物挥发性成分的差异分析

为探究不同还原糖与南极磷虾粉酶解液的美拉德反应(Maillard Reaction, MR)产物挥发性成分的差异, 以核糖、木糖、果糖、葡萄糖和半乳糖与南极磷虾粉酶解液进行MR, 检测其中间产物含量、褐变程度和感官品质, 并通过气相色谱-离子迁移谱(GC-IMS)和气相色谱-质谱(GC-MS)联用分析其挥发性风味成分. 结果表明, 核糖MR产物的中间产物含量最高, 褐变程度最大, 且色泽明亮、澄清均匀, 带有浓郁的虾香味. GC-IMS显示不同MR产物的挥发性风味物质有明显差异, 通过指纹图谱和主成分分析可以有效地区分. GC-MS则表明不同挥发性物质的含量和特征化合物造成MR产物的风味差异, 其中糠醛、2-环戊基环戊酮、2,5-二甲基吡嗪、顺-2-甲基-2-丁烯醛和吡嗪分别是5种还原糖MR产物的特征挥发性成分, 它们赋予了不同MR产物不一致的风味特征. 通过聚类热图可以直观展示不同MR产物挥发性物质的差异情况. 综合表明, 两种技术相结合, 互补优势, 获得了不同还原糖MR产物更全面的风味成分信息, 更加全面地反映不同还原糖MR产物中挥发性成分的差异, 可为南极磷虾粉MR还原糖的选取和风味产品的进一步开发提供科学依据.     

Frame wavelets in subspaces of

Let be a real expansive matrix. We characterize the reducing subspaces of for -dilation and the regular translation operators acting on We also characterize the Lebesgue measurable subsets of such that the function defined by inverse Fourier transform of generates through the same -dilation and the regular translation operators a normalized tight frame for a given reducing subspace. We prove that in each reducing subspace, the set of all such functions is nonempty and is also path connected in the regular -norm.

     

Coherent Solution‐phase Synthesis of a Germanium‐Graphitic Nanocomposite and Its Evaluation for Lithium‐Ion Battery Anodes: Non‐innocent Role of the Mashima Reagent

The organosilicon reagent 1,4‐bis‐(trimethylsilyl)‐1,4‐diaza‐2,5‐cyclohexadiene 2 plays the binary role of the simultaneous reduction of GeCl₂.dioxane 1 dissolved in oleylamine to Ge nanocrystals and the formation of graphitic sheets under hot‐injection conditions. This colloidal synthetic route to germanium nanocrystals embedded on N‐doped graphitic nanosheets Ge/NG is free of any template or catalyst and involves easy purification techniques. The Ge/NG/C obtained after carbonization has been explored for anode performance in lithium‐ion batteries. Both Ge/NG and Ge/NG/C can be obtained on a gram scale and are bottleable under argon for months.     

A novel approach towards chemoselective reduction of nitro to amine

Chemo selective reduction of a wide range of aromatic nitro compound has been performed by using inexpensive Zn powder and CuSO₄ system in water medium at room temperature. This system has high tolerance to other highly reducible groups present in nitro substance along with high conversation and selectivity. This chemo-selective reduction also provides a facile root for the synthesis of other industrially important fine chemicals or biologically important compounds where other highly reducible groups are present in close proximity to the targeted nitro groups.