高碘酸钠催化微晶纤维素的氧化

主要讨论了使用高碘酸钠(NaIO4)溶液氧化微晶纤维素的过程及性能,用红外光谱(IR)验证了氧化纤维素的生成;通过扫描电镜(SEM)、热重分析(TG-DSC)以及X射线衍射(XRD)对比了反应前后纤维素的变化;考察了氧化时间、氧化温度、氧化剂的浓度以及溶液的pH值对氧化纤维素的产率及醛基含量的影响;结果表明,反应前后纤维素的晶型和形貌基本没有变化,随着氧化程度的加深,氧化纤维素的热稳定性越来越差;并且随着氧化温度的提高和氧化剂浓度的增大,醛基含量相应提高,而氧化时间和pH值对醛基含量存在相对最高值。     

固定化血红蛋白氧载体的研究（Ⅱ）：氧化纤维素共价键联 …

以纤维素为载体，经高碘酸钠氧化后共价键联血红蛋白，制备氧载体。研究了氧化条件对血红蛋白固定量的影响。纤维素只有经过预氧化，碱处理和再氧化三步活化反应，才能使血红蛋白大量化，每克纤维素固定血红蛋白量达１．０ｇ。氧载体稳定性好，血红蛋白不脱落。经铁氰化钾氧化，氧载体放氧效率为３３．１％。     

新型两性球形离子交换纤维素的制备

本文在自制的球形纤维素基础上,以Ｆｅ＾２＋Ｈ２Ｏ２－二氧化硫脲为氧化还原引发系统,通过甲基丙为稀酸与丙烯酰胺的二元混合物与珠体纤维素接枝共聚,制得了含－ＮＨ２和－ＣＯＯＨ两种官能团的两性离子交换纤维素,其中阳离子交换容量在０．１５～０．６７ｍｍｏｌ／ｇ,阴离子交换容量在０．０５～０．５０ｍｍｏｌ／ｇ。该离子交换剂可用于生物大分子如蛋白质、肽的分离。     

纤维素醋酸酯的均相合成

纤维素的非均相反应取代不均匀、产率低。本文用纤维素在LiCl／DMAc溶液中的均相反应。制得了纤维素三醋酸酯(CTA)、纤维素二醋酸酯(CDA)、纤维素—醋酸酯(CMA)，并对产品结构性能进行了表征。     

固定化血红蛋白氧载体的研究(Ⅱ)——氧化纤维素共价键联血红蛋白

以纤维素为载体,经高碘酸钠氧化后共价键联血红蛋白,制备氧载体.研究了氧化条件对血红蛋白固定量的影响.纤维素只有经过预氧化、碱处理和再氧化三步活化反应,才能使血红蛋白大量固定化,每克纤维素固定血红蛋白量达1.0g.氧载体稳定性好,血红蛋白不脱落.经铁氰化钾氧化,氧载体放氧效率为33.1%.     

三维结构和氧化度对C6位氧化再生纤维素止血材料性能影响

C6位氧化再生纤维素作为可吸收止血材料,其止血性能受材料理化性质的影响。通过比较氧化再生纤维素的吸水率、凝胶化速率、溶解速率、降解速率、抗老化性能和止血效果,研究三维结构和氧化度对氧化再生纤维素性能影响。结果发现,氧化度增高,氧化再生纤维素吸水率增强,凝胶化速率加快,溶解速率和降解速率变快,抗老化性能变差,产品有效期变短。纤丝松散网状多孔结构比纱布致密结构更有利于提高吸水率,加快凝胶化速率和溶解速率;同时降低氧化剂用量,提高抗老化性能。同一氧化度条件下,纤丝止血速率优于纱布,止血效果更好。     

pH值对邻苯二亚胺纤维素的制备及荧光性能的影响

制备了席夫碱（Ｓｃｈｉｆｆ’ｓ ｂａｓｅ）邻苯二亚胺纤维素（ＰＤＩＭＣ），考查ｐＨ值对制备反应和产物荧光性能的影响。结果表明：氧化度为１００％的二醛纤维素在ｐＨ＝７￣１３、室温下、反应３０ｈ生成的邻苯二亚胺纤维素，具有强较的荧光性能，熔点４１０ｋ，分解温度为５７８Ｋ；ＰＤＩＭＣ水溶液在ＰＨ＝７．６，浓度为７．６×１０＾－４ｇ／ｍＬ，２０℃时，Ｅｘ＝４７０ｎｍ，Ｅｍ＝５５５ｎｍ处荧光最强。     

纤维素/甲壳素共混膜的结构表征与抗凝血性能

以 6wt %NaOH 4wt%尿素为纤维素的新溶剂 ,采用溶液共混法制备出纤维素 甲壳素共混膜 ,为甲壳素在碱性溶液中制膜提供了新的方法 .红外光谱、X 射线衍射、扫描电镜和力学性能、抗凝血性能测试结果表明 ,共混膜中甲壳素含量低于 4 0wt%时 ,纤维素与甲壳素分子间具有良好的相容性 ;在纤维素中引入适量甲壳素可提高共混膜的抗张强度 ,共混膜的干、湿态抗张强度在甲壳素含量 10wt%时最大 ,其值分别为 89 1MPa和 4 3 7MPa ,比纯态纤维素膜的干、湿态抗张强度分别提高了 6 7%和 11 5 % ;甲壳素的引入可明显降低血小板在共混膜表面的粘附、凝聚与变性 ,增大共混膜的抗凝血参数 ,甲壳素含量达到 5 0wt%时 ,该共混膜具有良好的抗凝血性能     

纤维素基磁性聚偕胺肟树脂的研究——溴在树脂上的氧化还原反应

用羟胺作模拟物与溴反应，测定了吸溴前后的酸式纤维素基磁性聚偕胺肟树脂的红外光谱，结合Ｆｒｅｕｎｄｌｉｃｈ及Ｌａｎｇｍｕｉｒ等温吸附方程的分析和吸溴前后树脂重量变化的测定，证明纤维素基磁性聚偕胺肟树脂吸溴后随即发生氧化还原反应，偕胺肟基被氧化为羧基，溴则被还原为溴离子，在溴浓度较高时，纤维素葡萄糖单元上的羟基被溴代或被氧化成羰酸，若葡萄糖苷键氧化断裂，将导致大分子降解。     

β-环糊精接枝纤维素纤维的研究

以环氧基为交联桥,制备了β-环糊精接枝纤维素纤维,获得了接枝最佳工艺条件,同时运用DSC和IR进行了表征。实验结果表明,环氧化反应乃接枝中关键步骤,其适宜工艺条件为:1g纤维素纤维所需环氧氯丙烷7mL,40%的NaOH溶液6mL,温度为40℃,时间为2.5h。侧链局部运动使纤维素纤维接枝β-环糊精后发生了次级转变。该研究有利于开发β-环糊精在纤维纺织工业的应用。     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。     

Acid hydrolysis of carboxymethylcellulose of low degree of substitution

Cotton cellulose was swollen in a sodium hydroxide solution and carboxymethylated by a two-bath method for different periods of time for each process. The kinetics of acid hydrolysis and the crystallinity of the swollen and carboxymethylated samples were measured. The proportion of broken bonds, rate constants for hydrolysis, and permeability of cellulose to hydrolyzing agents were calculated. The susceptibility of glycosidic linkages to acid hydrolysis was improved by carboxymethylation more than by swelling in alkali. The increased accessibility of carboxymethylcellulose to acid was regarded as a consequence of increased intra-and intercrystalline swelling and of the glycosidic bonds' weakness caused by the electron-attracting carboxymethyl group on the C-6 position.     

氯氧化镁生成热的研究

用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

Estimation of Kinetic Parameters of Thermal Oxidation of Ilmenite

The aim of the presented work was the investigation of thermal oxidation of ilmenite in static air atmosphere. The investigations were carried out by use of a derivatograph (MOM, Hungary). The changes of crystallographic structure of investigated samples were identified by X-ray diffractometry on Philips PW-1710 diffractometer. In temperature above 500°C appears structure of hematite Fe₂O₃. On the basis of the thermogravimetric measurements, the contracting area and contracting volume models were found as the best fitting experimental data. This revised version was published online in August 2006 with corrections to the Cover Date.     

Mechanism of action of base-catalyzed oxygenation of phenol derivatives

Cyclopropyl derivative of 2,6-di-tert-butylphenol is synthesized as a probe to investigate the mechanism of base-catalyzed autooxidation of phenol derivatives. Our study indicates that one electron reduction of molecular oxygen from phenolate gives phenoxyl radical 3, a key intermediate of autooxidation. The coupling of phenoxyl radical and superoxide radical gives peroxylate anion 4 and produces the final epoxy alcohol adduct 6.     

Synthesis of phenolic components of Grains of Paradise

Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.     

化学计量中不确定度评定研究进展

测量不确定度是表征合理地赋予被测量之值的分散性的参数。本文针对化学计量不确定度评定基础模型仅适用于线性模型、概率分布为正态分布或缩放位移t分布等局限,介绍了近年来不确定度评定的研究热点:蒙特卡罗方法(Monte Carlo Method,MCM),不确定度评定的来源、评定概念、评估方法及其发展过程,扩大了测量不确定度评定与表示的适用范围。     

微量钙的测定方法研究进展

介绍了1995-2006年期间测定微量和痕量钙的方法,如电感耦合等离子体-原子发射光谱法、原子吸收光谱法以及离子色谱法等的工作原理和特点,并说明了其测定微量钙的应用领域。并对微量钙的测定技术进行了展望(引用文献55篇)。