邻、对位羟基苯甲醛的气相色谱定量分析

邻、对位羟基苯甲醛是Reimer-Tiemann反应的主要产物。本文采用GC-6A型气相色谱仪,C-R3A色谱处理机,热导检测器,采用内标法同时定量分析邻、对位羟基苯甲醛,速度快、定量准确,回收率达90％以上,取得了比较满意的结果。     

论保险粉的定量分析

(一)引言保险船學名低亞硫酸鈉(sodium uydrcsuvlfite)其化學分子式Na_2S_2O_4为白色沙狀物结晶,无水保險粉本身還稳定,但其含水物(No_2S_2O_4·2H_2O),性質極不穩定。故成品必須储藏密封,以免吸收水分,遇了空氣中氧氣,     

羟基封端聚丁二烯的临界点色谱定量方法研究

为建立混合物中羟基封端聚丁二烯（HTPB）的临界点色谱定量方法,以C18为固定相,考察了HTPB在四氢呋喃-乙腈和四氢呋喃-水两种流动相体系下的临界点色谱条件。结果表明,四氢呋喃-乙腈体积比为70.7：29.3以及四氢呋喃-水体积比为92：8时,HTPB的保留值与其相对分子质量无关。将该临界点色谱方法用于胶黏剂混合组分中HTPB的测定,结果表明,HTPB在46.7~216.4 mg/L范围内呈良好线性关系,相关系数（r）>0.99,检出限为4.2 mg/L。自配HTPB和矿物油双组分样品的加标回收率为89.2%~101.1%,相对标准偏差小于0.66%（n=6）。应用该方法对市售聚氨酯胶黏剂进行检测,测定结果为HTPB成分占26.6%。该方法快速、准确,能满足聚合物混合产品的生产质量控制和失效分析的要求。     

蛋白质定量分析的进展

蛋白质是生命的起源,蛋白的定量分析涉及到生产与科研的各领域和与生命有关的许多行业。文中着重阐述了化述法和免疫法在定量分析蛋白质中的应用及发展动态。     

含三氟苯基8-羟基喹啉锌配合物的合成及紫外、荧光性能对比研究

设计合成了两种含三氟苯基的新型8-羟基喹啉衍生物配体:(E)-2-[2-(2,4,6-三氟苯基)乙烯基]-8-羟基喹啉(B)、(E)-5-[2-(2,4,6-三氟苯基)亚胺基]-8-羟基喹啉(C)及其相应的锌配合物D与E,产物经NMR,IR,MS,元素分析等进行结构表征。通过核磁、紫外滴定跟踪了金属锌与配体的配位过程,并测定了两者溶液状态下的荧光性质:化合物D,E在甲醇溶液中的荧光发射峰位置分别在599 nm和572 nm处;相比于8-羟基喹啉,2位和5位取代8-羟基喹啉衍生物的荧光发生了明显红移。锌配合物固体荧光寿命的测定结果表明,配合物D表现出较长的荧光寿命。     

胆红素定量分析的研究进展

在临床应用和实验研究中,胆红素的定量分析方法已经取得了长足的发展,有多种方法可以定量分析胆红素的浓度。本文对胆红素定量分析方法及理论依据作一综述。     

关于透光率导数光谱用作定量分析的可行性

探讨了我率导数光谱（d^nT/dλ^n）与吸光度导数光谱（d^nA/dλ^n）的关系，并讨论了用d^nT/dλ^n作定量分析的可行性及其产生分析误差的原因以及最佳测量条件。     

1-羟基异喹啉及羟基Fasudil的合成

首先以异喹啉为原料,经氧化生成氮氧化物后与苯甲酰氯和水作用,得到1-羟基异喹啉,收率为73.3%.以Fasudil为原料,经氨基保护、氧化,在相转移催化剂的存在下,于二氯甲烷和水的两相体系中与苯甲酰氯和水作用,合成羟基Fasudil,HPLC纯度大于99%,总收率为46.8%,从而建立了一条条件温和、操作简便的羟基Fasudil的合成工艺路线.     

端羟基聚丁二烯/环氧氯丙烷合成多羟基聚丁二烯的实验研究

在氢氧化钠碱性条件下,以端羟基聚丁二烯(HTPB)和环氧氯丙烷(ECH)为原料,四丁基溴化铵(TBAB)为催化剂,制得多羟基聚丁二烯(PHPB)。采用红外光谱(IR)、热重分析仪(TG)、核磁共振(1 H-MNR)对原料、中间产物和产物的结构和热稳定性进行了分析。通过产品的羟值、粘度和产率详细考察了反应温度、反应时间、原料配比、催化剂用量和氢氧化钠用量对PHPB合成的影响。结果表明,最适宜合成工艺条件为:反应温度为55℃,反应时间1.5h,n(HTPB)∶n(ECH)∶n(NaOH)∶n(TBAB)=1∶2.9∶3∶0.03。     

最小二乘—红外光谱法定量测定羟基化合物

根据羟基伸缩振动吸收带的特性，用最小二乘法有效消除了溶液中羟基间的缔合作用对测定结果的影响。此方法已用于聚合物中羟基含量的测定。     

Synthesis and Electrochemical Studies on BEDT-TTF Derivatives with Hydroxyl Groups

Since the finding of organic conductor in 1973 and organic superconductor in 1980, great progress has been achieved1 in the field of organic conductors and superconductors. Much effort is still being devoted to this field, and several significant results have been obtained by subtle modifications of BEDT-TTF, such as, the substitution of peripheral sulfur atoms with selenium ( BETS )2 and oxygen ( BEDO)3atoms, the extra-substitution with hydroxyl , amide, pyridine groups4 etc., all of the…     

Reactivity of Aliphatic and Phenolic Hydroxyl Groups in Kraft Lignin towards 4,4′ MDI

Several efforts have been dedicated to the development of lignin-based polyurethanes (PU) in recent years. The low and heterogeneous reactivity of lignin hydroxyl groups towards diisocyanates, arising from their highly complex chemical structure, limits the application of this biopolymer in PU synthesis. Besides the well-known differences in the reactivity of aliphatic and aromatic hydroxyl groups, experimental work in which the reactivity of both types of hydroxyl, especially the aromatic ones present in syringyl (S-unit), guaiacyl (G-unit), and p-hydroxyphenyl (H-unit) building units are considered and compared, is still lacking in the literature. In this work, the hydroxyl reactivity of two kraft lignin grades towards 4,4′-diphenylmethane diisocyanate (MDI) was investigated. ³¹P NMR allowed the monitoring of the reactivity of each hydroxyl group in the lignin structure. FTIR spectra revealed the evolution of peaks related to hydroxyl consumption and urethane formation. These results might support new PU developments, including the use of unmodified lignin and the synthesis of MDI-functionalized biopolymers or prepolymers.     

Electrocatalytic Hydrogen Evolution of the Cobalt Triaryl Corroles Bearing Hydroxyl Groups

Three isomeric A₂B-type new cobalt triaryl corroles bearing hydroxyphenyl substituents have been prepared and well characterized. Their activity and stability in the electrocatalytic hydrogen evolution reaction (HER) have been investigated. The results showed that the hydroxyl position of the phenyl group had significant influence on electrocatalytic HER. The ortho-hydroxyphenyl substituted cobalt corrole ( 1 ) core displays the best HER activity using TsOH proton source, and the turnover frequency (TOF) and catalytic efficiency (C.E) reach 318.68 s⁻¹ and 1.13, respectively. Moreover, a turnover number (TON) of 1447.39 and Faraday efficiency (FE) of 98.7 % have been observed in aqueous medium. The catalytic pathway is via EECEC, EECC or ECEC pathways depending on the acidity of acid proton source (E: electron transfer step, C: chemical step, in this case protonation). The catalytic HER performance of these cobalt corroles follows an order of o-hydroxyl > p-hydroxyl > m-hydroxyl isomer, showing the o- and p-hydroxyl of the phenyl groups are more efficient in accelerating proton relay.     

含羟基和咪唑基团新手性肽核酸的设计与合成

以含丝氨酸和组氨酸残基的手性肽核酸单体替换经典肽核酸单体, 采用固相合成方法设计合成了五个新序列含羟基和咪唑基团的10聚体手性肽核酸, 经ESI-MS或MALDI-TOF-MS证实目标物结构正确.     

三溴异氰脲酸和DABCI-Br作为高效催化剂用于羟基硅烷化

The protection and deprotection of functionalgroups are indispensable in the synthesis of polyfunc-tional compounds.In addition,several chemical con-versions and multiple sequence syntheses are often re-quired for the protection of hydroxyl groups.Thesily…     

Microdetermination of Adjacent Hydroxyl Groups in Organic Compounds

Abstract

A simple method is described for determination of the number of adjacent hydroxyls in an organic compound. This method involves a digestion of the sample with hydriodic acid in a closed tube. The amount of iodine produced in the digestion (i.e., N-1 moles) is related to the number of adjacent hydroxyls in the molecule (i.e., N).     

羟基聚合铝溶液的27Al 核磁(NMR)研究进展

结合国内外各课题组研究,从27Al NMR实验参数和铝形态研究两方面综合评述了液体27Al NMR的发展研究现况。首次明确提出27Al NMR测定中设置合适的预采集延迟时间的作用。将为进一步开展的27Al NMR测定研究提供有价值的参考。     

Polyurethanes with Pendant Hydroxyl Groups: Synthesis and Characterization

Communication: Phenoxycarbonyloxymethyl ethylene carbonate 4 was synthesized from glycerol carbonate and phenyl chloroformate. Polyurethanes with pendant hydroxyl groups were obtained from polycondensation reactions of this AA* monomer with diamines. These polymers contain primary as well as secondary hydroxyl groups. The obtained polyurethanes are amorphous materials. The glass transition temperature decreases with increasing number of methylene groups between the urethane groups.

As the number of methylene groups increases between the urethane groups, the glass transition temperature of the polymer decreases.     

糖合成中羟基的保护和去保护方法

糖中含有多个活泼的羟基.羟基的保护和去保护在有关糖的合成中具有很重要的意义.最常用的羟基保护基可归纳为三类:酯类、醚类和缩醛或缩酮类.作者对每一类中具体的羟基保护基的性质、应用作了简单综述,重点介绍了保护基的引入和脱去的方法.