Conversion of graphite into mellitic acid

A fast one step oxidation method for converting poorly crystalline graphite, identified by its X-ray diffraction angle of from 26.5 to 26.7°, into mellitic acid has been developed. The oxidant used is a mixture consisting of nitric, sulphuric, and perchloric acids in a ratio of 1:6:1. Oxidation goes to completion within 7 hr at atmospheric pressure and the reaction time can be further reduced to 1.25–2.5 hr by the presence of a catalyst such as V₂O₅, MoO₃, PbO₂, Al₂O₃, Ag₂O or Na₂O₂. The reaction product was found to contain only mellitic acid with an over-all yield of about 30%.     

Lipase-catalyzed synthesis of kojic acid esters in organic solvents

Kojic acid is an inhibitor of bacteria, viruses, and fungi. It is used for inhibiting the browning effect of tyrosinase in the food and cosmetic industries. To improve its lipophilic properties, Pseudomonas cepacia lipase and Penicillium camembertii lipase were used for catalyzing the esterification of kojic acid to synthesize kojic acid monolaurate and kojic acid monooleate. These products showed a 69.5% inhibitory effect on tyrosinase in hydrophobic organic solvent. The yields of kojic acid esters were affected by enzymes, substrates, organic solvent, and temperature. Lauric and oleic acids were the best substrates for esterification among various fatty acids tested. CaCl₂ and MnCl₂ stimulate Pseudomonas cepacia lipasecatalyzed esterification by 7.0%. On the contrary, MgCl₂, SrCl₂, and ZnCl₂ inhibited the reaction. The best pH of buffer for lipase pretreatment was pH 6.0. Pseudomonas and Penicillium lipases can be reused for the synthesis of kojic acid esters. After reaction at 40°C for 10 d, the Penicillium and Pseudomonas lipases still retained 57.0% and 92.0% of their initial activities, respectively.     

离子对高效液相色谱法分析化妆品中的曲酸

建立了化妆品中曲酸(KA)的离子对高效液相色谱法。采用0．01mol／L磷酸氢二钠-甲醇(95：5,V／V)为流动相,添加1．0mmol／L四丁基溴化胺(TBA),检测波长226nm,样品用40％甲醇超声提取,曲酸在Nova-Pak C18柱上获得了良好分离。该方法的检出限为0．024mg／L,回收率为93．9％～101．2％,相对标准偏差为0．97％～1．81％。     

白藜芦醇及其衍生物和类似物抗肿瘤研究进展

白藜芦醇具有广泛的生物学活性,尤其是抗肿瘤作用备受关注,得到了广泛研究。同时,为了提高生物利用度,并获得更高的抗肿瘤活性,有关其衍生物与类似物的研究也大量开展。本文对白藜芦醇的结构及理化性质、抗肿瘤作用机制、毒性、代谢动力学、白藜芦醇衍生物和类似物的抗肿瘤活性及作用机制,以及制备方法进行了回顾。作为一类很有希望的的新型抗肿瘤药物,有关白藜芦醇及其衍生物和类似物还存在许多需要继续研究的问题,包括生物作用机制、结构与活性的关系不明确、生物利用度与疗效之间存在的矛盾以及体内药代动力学研究的缺乏等,还需要系统开展作用机制、毒理学和代谢动力学研究以及动物体内试验。     

半纤维素制备糠醛的研究进展

对糠醛的性质及其主要应用领域的应用现状进行了描述,介绍了国内外由半纤维素为原料,以不同种类的催化剂(均相布朗斯无机酸、均相有机酸、固体酸、金属盐)为主线制备糠醛的工艺路线,并对,并对它们的催化效果和优缺点做了比较。     

Insights into the coordination sphere of copper ion in polymers containing carboxylic acid and azole groups

In this work, we describe the Cu²⁺ ion uptake from recently developed hydrogel with polyampholyte and polyelectrolyte behavior at different concentrations of the metal ion. Solid-state NMR and EPR were used as complementary techniques to understand the coordination role of carboxylic acid and azole groups (imidazole, triazole and pyrazole) involved in the copper ion coordination. In polymers containing imidazole and triazole, the uptake took place preferentially through the azole groups, with less participation of the carboxylate groups at low concentrations of Cu²⁺. However, as the concentration of Cu²⁺ increased, these azole ligands became less active in the new sites for copper. In polymers containing pyrazole, coordination of Cu²⁺ was through both carboxylate and pyrazole ligands, regardless of the concentration of Cu²⁺.     

4-甲基-7-羟基-8-醛香豆素的合成与表征

采用间苯二酚和乙酰乙酸乙酯为原料,合成了4-甲基-7-羟基香豆素。4-甲基-7-羟基香豆素和六次甲基四胺在冰醋酸中反应,简单处理后得到4-甲基-7-羟基-8-醛基香豆素。对所合成的醛基香豆素采用IR、1HNMR进行了结构表征和确认。该反应操作简单,后处理简便,产率较高。     

Influence of fatty alcohol and other fatty acid derivatives on fatty acid uptake into rat intestinal epithelial cells

We investigated the influence of various substrates on the uptake of long-chain fatty acid into IEC-6, rat intestinal epithelial cell line. The uptake of [³H]oleic acid into IEC-6 cells was a saturable function of the oleic acid concentration. Long-chain fatty acids significantly inhibited the oleic acid uptake into IEC-6 cells and shorter-chain fatty acids had little or no effect. Various fatty acid esters suppressed the oleic acid uptake into IEC-6. Fatty alcohols also inhibited oleic acid uptake into IEC-6 and the length of the carbon chain played an important role. These results suggest that long-chain fatty acid uptake was inhibited by the substrates which had a structure similar to long-chain fatty acids, especially those with a long carbon chain. At least two molecules, fatty acid translocase and fatty acid transport protein type 4, which are considered to be involved in the long-chain fatty acid transport into the cell, were expressed on IEC-6 cells, supporting the existence of the carrier-mediated system of long-chain fatty acid transport on IEC-6 cells.     

曲酸双棕榈酸酯的制备和性能

研究了新型美白剂曲酸双棕榈酸酯的合成。该合成由棕榈酸的酰氯化和棕榈酰氯与曲酸的缩合两步反应完成。对棕榈酰氯制备过程中棕榈酸与PCl3的摩尔比、反应时间等工艺条件进行了考察,获得了适宜的棕榈酰氯的制备方法。采用了正交实验法对曲酸与棕榈酰氯的缩合反应(酯化反应)的工艺条件进行了优化,获得酯化反应的最佳工艺条件为:n(曲酸)/n(棕榈酰氯)为1 0/2 5,反应温度为35℃,反应时间为2h,丙酮用量为18mL/g曲酸,吡啶用量为3mL/g曲酸。在此条件下,酯化转化率可达88 9%,重结晶纯化得熔点为92℃～94℃的白色固体产品。     

氰基及酯基改性聚羧酸减水剂性能研究

在异戊烯醇聚氧乙烯醚(TPEG)和丙烯酸(AA)二元共聚合成聚羧酸减水剂PCAl的基础上,分别以丙烯腈(AN)、丙烯酸羟乙酯(HA),以及马来酸二甲酯(DMM)为改性单体,实现了三元共聚进行聚羧酸减水剂(PCA)的改性合成PCA2、PCA3、PCA4,显著提高了PCA的减水率、保坍性.四种PCA的分散机理初步研究表明:氰基、酯基的水解对初始分散及分散保持能力影响显著;氰基改性PCA分散性最好,水泥浆体屈服应力最低,更接近牛顿流体;在掺量为0.20％时,马来酸二甲酯改性PCA的新拌混凝土减水率为34.80％,混凝土坍落度1h坍落度增长2.22％,实现了高减水且具有一定缓释效应.     

几种查尔酮吡啶衍生物的合成

查尔酮是一类具有生物活性的天然产物,是黄酮类化合物重要组成部分。自然界中也存在着大量吡啶衍生物,吡啶环结构也是许多天然产物的重要结构单元。以2-乙酰基吡啶和取代的芳香醛为原料,在碱存在下,通过Clasien-Schmit反应,合成了7种不同的查尔酮吡啶衍生物。优化了合成条件,并对这些查尔酮进行了1H NMR、13CNMR、ESI-MS表征。所用方法绿色高效且具有较高的实用性,为该类化合物的大量制备提供了可行的合成策略。     

Surface modification and biological evaluation of kojic acid/silica nanoparticles as platforms for biomedical systems

Kojic acid (KA), an important compound with medical, cosmetic, and industrial applications, was loaded in 3-aminopropyltriethoxysilane-functionalized silica nanoparticle (MSNAPTES-KA5). This nanoparticle with acid was prepared to evaluate its application as a drug delivery system due to its interesting characteristic as large surface area, high pore volume, and good biocompatibility. The samples were characterized using different techniques that demonstrate success in the functionalization and loading process, as can be seen from the results obtained by FTIR, XPS, TGA, and CHN, that confirmed the presence of APTES and KA in the nanoparticles. KA drug loading was estimated using UV-Vis, TGA, and CHN, which revealed 12% loading of KA in the nanoparticles that showed slow rate of release. Antimicrobial assay was performed to evaluate the antimicrobial activity of the samples against different microorganisms. The results showed greater MSNAPTES-KA5 antibacterial activity than free-kojic acid for Candida albicans and Staphylococcus aureus. In relation to the acetylcholinesterase (AChE) inhibition assay; a higher inhibition of MSNAPTES-KA5, than the inhibition with free-kojic acid was observed. In addition, MSNAPTES-KA5 sample was also effective in inhibiting tyrosinase, proving the efficiency of the MSNAPTES base. These studies afford evidence of the possible beneficial biological activities of MSNAPTES-KA5 nanoparticle in pharmaceutical applications.     

α-硫辛酸合成方法及其衍生物的研究进展

α-硫辛酸是生物体中广泛存在的一种具有多生物活性的重要化合物,综述了近几年来α-硫辛酸、(R)-α-硫辛酸及其衍生物的合成方法的研究进展,并对各方法的发展前景进行了展望。     

乙醛酸主要衍生物的合成及应用

简述了乙醛酸的主要衍生物包括尿囊素、对羟基苯乙酸、2-羟基膦乙酸、对羟基苯海因及对羟基苯甘氨酸等几种产品的主要物性，介绍了它们的主要合成方法及应用领域，着重讲述了乙醛酸法生产上述产品的工艺过程及优点。     

Biochemical Conversion of Microalgae Biomass into Biofuel

Biofuel production via microalgae is a promising and sustainable alternative to replace the typical fossil fuel that is the main contributor to the global warming. However, for a cost‐effective biofuel production, further advanced research is still needed for large‐scale operation. This article is a tutorial review on conversion processes of microalgae into biofuel, with emphasis on biochemical conversion. The following topics are discussed: (i) microalgae biomass and its composition, (ii) thermochemical conversion, (iii) chemical conversion, and (iv) biochemical conversion. In addition, various aspects of anaerobic digestion, digester designs, and effects of operating conditions on the production of methane, bioethanol, and biohydrogen are discussed. The general kinetics of biomass conversion into biofuel is presented. This study suggests, if that biomass contains less than 50 % moisture, then it is recommended to use the direct combustion method; otherwise, biochemical conversion is the most suitable process to biofuel production.