Pd/La0.5Pb0.5MnO3催化氧化甲苷合成葡萄糖醛酸

采用沉淀法制备了以钙钛矿型复合金属氧化物为载体的催化剂Pd/La0.5Pb0.5MnO3,催化氧化甲基葡萄糖苷合成甲苷酸钠,进一步水解反应生成葡萄糖醛酸. 利用XRD和SEM对催化剂进行了表征,考察了催化剂制备和氧化工艺条件对葡萄糖醛酸收率的影响. 结果表明,在Pd负载量为1%、原料与催化剂质量比为6:1、温度70℃、压力为常压、pH值9、时间5 h的条件下,葡萄糖醛酸的收率达到29.5%,反应选择性较好.     

对硝基苯基—β—D—葡萄糖醛酸苷钠盐的合成

以葡萄糖醛酸内酯和对硝基酚为原料，经过五步反应合成了对硝基苯基－β－Ｄ葡萄糖醛酸苷钠盐，熔点２２０℃，并用红外和核磁共振予以确认。以ＰＮＰ－ＧＵＡ为底物，在检测环境样品的大肠杆菌中，得到满意的后果。     

三-O-乙酰基-α-D-溴代葡萄糖醛酸甲酯的合成

以葡醛酸内酯为原料,通过酯交换、乙酰化和溴代反应合成三-O-乙酰基-α-D-溴代葡萄糖醛酸甲酯。采用五溴化磷代替溴化氢作为溴化剂,合成化合物的结构通过1H NMR及旋光度测定确证无误,总收率72%。     

葡萄糖酸钠的制备方法

介绍了葡萄糖酸钠的特性和用途,综述了以葡萄糖为基本原料制备葡萄糖酸钠的4种合成方法--生物发酵法、均相化学氧化法、电解氧化法、多相催化氧化法,同时强调多相催化氧化法在工业化生产中具有较大的应用潜力.     

芥酸氧化制备十三烷二酸和十三烷醛酸乙酯的研究

本文以芥酸为原料，分别用高锰酸钾氧化法和过氧化氢氧化法制得了十三烷二酸和十三烷醛酸乙酯。并通过方法改进，在高锰酸钾氧化法的两相溶液体系中加入四了基氯化铵作为相转移催化剂。在过氧化氢氧化法中，以甲酸-过氧化氢代替文献上的浓硫酸-冰醋酸-过氧化氢，结果，分别使以上两种产物的产率得到显著提高。本文同时考察了反应温度、时间以及溶剂改变对高锰酸钾氧化法的影响，获得了氧化反应的最佳条件。     

肝素热点问题浅谈

肝素是一种分子量为20000左右，含硫量为9％～12．9％的酸性粘多糖，属于不均一的多糖分子。其链节单位系由葡萄糖胺磺酸，葡萄糖醛酸及艾社糖磺醛酸等所组成。[第一段]     

速生杨半纤维素碱法提取工艺的优化和表征

在 50 ℃ 下,对速生杨木粉原料进行苯-醇预处理,得到脱脂杨木粉。后进行超声波乙醇-碱处理,得到碱脱木质素杨木粉。再运用正交试验设计法研究了抽提温度、抽提时间和NaOH溶液质量分数对速生杨半纤维素得率的影响。结果表明:NaOH溶液质量分数对半纤维素的提取率影响最为显著,而抽提时间的影响最小。最佳抽提条件为:抽提温度 90 ℃、抽提时间 12 h、NaOH溶液质量分数 8 %,在此条件下的半纤维素的提取率为 87.20 %。通过傅里叶红外光谱,核磁共振光谱和组成分析,结果发现,碱法抽提所得半纤维素的主要成分是4-O-甲基葡萄糖醛酸基-木聚糖,木糖和葡萄糖醛酸糖基物质的量之比为22.83∶1,同时含有少量甘露糖、葡萄糖和半乳糖,它们的含量分别为 2.87 %、 0.83 % 和 0.55 %,对应的糖基比为3.46∶1∶0.66, 4-O-甲基葡萄糖醛酸基-木聚糖和葡萄糖基甘露聚糖两种半纤维素分别占 86 % 和 4 %,阿拉伯糖基木聚糖含量较低,另外含有约 4.5 % 木质素组分。     

葡萄糖氧化制草酸

针对目前国内草酸生产成本高、工艺复杂等缺点,开展了葡萄糖氧化制草酸的工艺研究。以蔗糖、葡萄糖等碳水化合物为原料,在硫酸、硝酸和水的混合物为氧化介质的反应体系中氧化为草酸。在优化工艺条件下:硫酸的浓度为50%,反应温度60～65℃,m(葡萄糖)∶m(硝酸)=1∶3.2,催化剂的加入量为0.05%(以葡萄糖计,m/m),加料时间6h,母液循环使用。每吨葡萄糖可产草酸1.65～1.75t,收率达90%以上。     

化妆品天然成分原料介绍(ⅩⅦ)

正1聚葡糖醛酸(Polyglucuronic acid)聚葡糖醛酸(Polyglucuronic acid)是一多糖类化合物,在绿藻等低等藻类生物中发现,是它们细胞壁的组成部分。聚葡糖醛酸的葡萄糖醛酸以β-1,4位的方式连接,现可用发酵法生产,也可化学合成。化学结构为:     

产紫青霉β-葡萄糖醛酸苷酶基因的克隆与原核表达

产紫青霉（Penicillium purpurogenum Li-3）β-葡萄糖醛酸苷酶可定向转化甘草酸生成单葡萄糖醛酸基甘草次酸。根据β-葡萄糖醛酸苷酶氨基酸序列的同源保守区设计简并引物,PCR扩增克隆得到β-葡萄糖醛酸苷酶编码基因pgus(GenBank登录号：EU095019),该基因全长1815bp,编码604个氨基酸,理论单亚基分子量为67.77×10³,含有4个潜在的N-糖基化位点。构建原核表达载体pET-28a(+)-pgus,转化大肠杆菌BL21（DE3）,获得高效表达pgus基因的重组菌。经IPTG诱导表达、Ni²⁺-NTA亲和层析柱纯化的重组酶PGUS-E,纯度达到95%以上,得率为25.6 mg•L^-1,SDS-PAGE分析检测分子量约为70×10³,比酶活达到6368 U•mg^-1。     

煤氧化解聚的研究进展

综述了国内外关于由煤的氧化解聚获得有机化学品的研究进展,介绍了氧化解聚的方法、机理、产物分布及其优缺点等,并探讨了今后的发展趋势。认为由煤的氧化解聚制取高附加值化学品是可行的,是一条值得探索的煤高效利用之路。     

碳酸二甲酯的生产与技术经济

介绍了ＤＭＣ的用途、国内外市场需求及生产方法，对ＥＮＩ的液相氧化羰基化法和日本宇部兴产的气相氧化羰基化法进行了技术经济比较，并从工程设计角度对国内建设氧化羰基化法ＤＭＣ装置进行了经济评价。     

The electrocatalytic oxidative polymerizations of aniline and aniline derivatives by graphene

Graphene oxide (GO) on a glassy carbon (GC) electrode was directly reduced at −1.0 V in a phosphate buffer (pH 4.15) to form graphene/GC electrode, which was used for the electrocatalytic oxidative polymerizations of aniline, o-aminophenol, and m-aminophenol in the acidic solutions using cyclic voltammetry, amperometric and potentiometric methods. Cyclic voltammograms demonstrate that the oxidation peak of aniline on the first cycle shifts from 1.13 V on the bare GC electrode to 0.76 V on the graphene/GC electrode. In addition, both amperometric and potentiometric methods also demonstrate that graphene can effectively catalyze the electrochemical oxidative polymerization of aniline. Cyclic voltammetry confirmed that graphene can pronouncedly catalyze the electrochemical oxidative polymerizations of o-aminophenol and m-aminophenol, but graphene oxide hardly catalyzes the electrochemical oxidative polymerizations of aniline and its derivatives. The ESR spectrum of graphene is quite different from that of graphene oxide.     

由甲醇制备碳酸二甲酯的生产技术

综述了由甲醇制备碳酸二甲酯的各种生产方法及其发展趋势，特别是对新的非光气法－－甲醇氧化羰基化生产碳酸二甲酯进行了较为详细的论述。     

Metabolomics of oxidative stress in recent studies of endogenous and exogenously administered intermediate metabolites

Aerobic metabolism occurs in a background of oxygen radicals and reactive oxygen species (ROS) that originate from the incomplete reduction of molecular oxygen in electron transfer reactions. The essential role of aerobic metabolism, the generation and consumption of ATP and other high energy phosphates, sustains a balance of approximately 3000 essential human metabolites that serve not only as nutrients, but also as antioxidants, neurotransmitters, osmolytes, and participants in ligand-based and other cellular signaling. In hypoxia, ischemia, and oxidative stress, where pathological circumstances cause oxygen radicals to form at a rate greater than is possible for their consumption, changes in the composition of metabolite ensembles, or metabolomes, can be associated with physiological changes. Metabolomics and metabonomics are a scientific disciplines that focuse on quantifying dynamic metabolome responses, using multivariate analytical approaches derived from methods within genomics, a discipline that consolidated innovative analysis techniques for situations where the number of biomarkers (metabolites in our case) greatly exceeds the number of subjects. This review focuses on the behavior of cytosolic, mitochondrial, and redox metabolites in ameliorating or exacerbating oxidative stress. After reviewing work regarding a small number of metabolites-pyruvate, ethyl pyruvate, and fructose-1,6-bisphosphate-whose exogenous administration was found to ameliorate oxidative stress, a subsequent section reviews basic multivariate statistical methods common in metabolomics research, and their application in human and preclinical studies emphasizing oxidative stress. Particular attention is paid to new NMR spectroscopy methods in metabolomics and metabonomics. Because complex relationships connect oxidative stress to so many physiological processes, studies from different disciplines were reviewed. All, however, shared the common goal of ultimately developing "omics"-based, diagnostic tests to help influence therapies.     

印刷线路板含铜废蚀刻液的回用处理(二)

介绍了几种印刷线路板铜蚀刻废液的回用处理工艺(如电解再生法、氧化再生法)及其所用材料(包括电极和萃取剂),概述了几种从铜蚀刻废液中回收资源的方法(如利用碱氨蚀刻废液制备胆矾或氯化亚铜).     

Study of rubber oxidation by thermoanalysis

A method using the DSC was utilized whereby the oxidation of natural rubber was studied by adapting the procedures developed by Kissinger, Doyle, and Ozawa for thermoanalysis. Thus oxidative induction time of several hours for a particular rubber sample can be estimated in a relatively short time. Some of the results of this method are compared with those from other established methods, the estimated oxidative induction time showing a good correlation with some of the systems tested. The validity and limitations of this method are discussed.     

汽油和柴油氧化脱硫技术进展

综述了国内外汽油、柴油氧化脱硫技术进展。介绍了选择性氧化脱硫、超声波氧化脱硫、光催化氧化脱硫、等离子体液相氧化脱硫、生物氧化脱硫、电化学氧化脱硫等。认为进一步探讨脱硫机理,提高脱硫效率和油品收率,降低脱硫成本,是氧化脱硫技术研究的重要方向。     

“绿色”化学品—碳酸二甲酯合成方法述评

介绍了碳酸二甲酯的各种合成方法,从技术、经济、环保角度,指出适合工业上采用的合成方法：（１）氧化羰基化法－甲醇、一氧化碳与氧气反应法;（２）直接羰基化法－甲醇与二氧化碳反应法。     

家用洗涤剂中的氧漂白体系(英)

洗涤过程中氧漂白对去除污斑起着重要的作用，介绍了活性氧漂白体系的生产、活化和应用过程。还了工业上可接受氧漂白产品的市场需求。