EDTA改性高吸水树脂对铜离子的吸附研究

以丙烯酸(AA)为单体,EDTA二钠为改性添加剂,过硫酸铵(APS)/亚硫酸钠为氧化还原型引发剂,N,N'-亚甲基双丙烯酰胺(NMBA)为交联剂,采用水溶液聚合法合成EDTA改性高吸水树脂。发现使用改性添加剂EDTA二钠能够使改性高吸水树脂的吸附铜离子性能明显增强。通过正交实验和单因素实验进行条件优化,得出改性高吸水树脂对重金属铜离子吸附性能最佳的工艺条件为:以15 mL的丙烯酸为基准,反应温度为65℃,单体质量分数为23.08%,中和度为65%,改性添加剂质量为0.4 g,交联剂和引发剂质量分别为聚合单体质量的0.9%和1.5%。在最佳工艺条件下,制备的改性高吸水树脂常温下在0.1mol·L~(-1)的硫酸铜溶液中吸附铜离子量达到225.18 mg·g~(-1)。     

含氮给体结构对丙烯腈电荷转移光聚合的影响

<正> 对于正性烯类单体,主要是乙烯基咔唑的电荷转移聚合,诚田已作过详细综述。负性烯类单体的电荷转移聚合主要研究的单体是丙烯腈(AN)及甲基丙烯酸甲酯(MMA)。Barton等研究了芳烃为引发剂的MMA光聚合。我们研究了芳胺为引发剂的光聚合。 芳胺,尤其是芳叔胺,是较强的电子给体,与负性单体在光照下经激基复合物而引发聚合,我们的实验表明,吡啶及其同系物(喹啉与吖啶)并不象吡咯及其同系物(吲哚与咔唑)那样有效地引发AN等负性单体的光聚合(见表1)。从图1所示的结构看,它们有     

紫外光聚合法制备棉秆纤维素接枝丙烯酸-腐植酸高吸水树脂及其性能

以丙烯酸(AA)、改性棉秆纤维素(MCSC)和腐植酸(HA)为原料,2,2-二甲氧基-苯基甲酮为引发剂,采用紫外光聚合法制备了降解性复合高吸水树脂(MCSC-g-PAA/HA)。用红外光谱和扫描电镜对产物进行了表征。研究了AA的浓度、MCSC和HA的含量、反应时间和光引发剂的添加量等因素对该树脂溶胀性能的影响。通过测定该树脂的吸水速率和土壤中的保水率及降解性,研究了盐溶液浓度对树脂吸液率的影响。结果表明,在优化条件下,所得树脂在蒸馏水和食盐水(w(NaCl)=0.9%)中的吸液率分别达到870 g/g与94 g/g。     

可聚合的光引发转移终止剂合成接枝共聚物

采用一种可聚合的光引发转移终止剂 ,2 N ,N 二乙基二硫代氨基甲酰氧基乙酸 β 甲基丙烯酰氧基乙酯 (MAEDCA) ,通过两种途径制备了含有聚甲基丙烯酸甲酯 (PMMA)和聚苯乙烯 (PSt)链段的接枝共聚物 .其一是将MAEDCA作为引发剂 ,在紫外光照射下引发MMA聚合 ,得到大分子单体 ,通过大分子单体与St的共聚合得到 .考察了所用大分子单体的分子量和浓度对共聚合的影响 .其二是将MAEDCA作为单体与MMA共聚得到侧链上含有N ,N 二乙基二硫代氨基甲酰氧基 (DC)基团的无规共聚物 ,P(MMA co MAEDCA) .在紫外光照射下 ,P(MMA co MAEDCA)作为大分子引发剂引发St聚合 ,得到P(MMA co MAEDCA) g PSt的共聚物 ,研究了接枝共聚合过程的活性自由基聚合特征     

光引发常规乳液聚合制备氨基聚苯乙烯纳米粒子

采用一种简单易行的方法制备了氨基功能化的聚苯乙烯纳米粒子.首先,采用4-乙烯基苄氯与1,3-丙二胺置换反应制备了含有氨基功能基团的可聚合单体N-(3-氨基丙基)对乙烯基苄基亚胺(CVPD).然后,采用乳液聚合,以苯乙烯(St)和CVPD为共聚单体,水溶性的4-(2-羟乙氧基)苯基-(2-羟基-2-丙基)酮(Irgacure 2959)为光引发剂,十六烷基三甲基溴化铵(CTAB)为乳化剂,经紫外光辐照引发,合成了P(St-co-CVPD)二元共聚物的纳米胶乳.体系的乳化剂用量仅为体系总质量的0.1 wt%～0.8 wt%,远小于常用来制备纳米粒子的微乳液体系的乳化剂用量.用透射电子显微镜(TEM)和激光粒度分析仪(DLS)表征了P(St-co-CVPD)纳米粒子的粒径和粒径分布.用红外光谱(FTIR)和核磁共振(NMR)证明了P(St-co-CVPD)纳米粒子上氨基的存在,并通过茚三酮显色反应定量检测了氨基含量.分别研究了单体配比,引发剂浓度,乳化剂用量以及紫外光强度对反应体系的影响.实验结果表明,产物粒子尺寸为30～600 nm,氨基通过共价键连接在粒子上,其含量为1.2×10-5～1.6×10-4 mol/g.该乳液体系聚合反应速率较快,单体转化率在60 min内即可达到80%.所得粒子的氨基含量可以通过单体配比进行调节.粒子尺寸可通过单体配比,引发剂浓度,乳化剂用量以及紫外光强度进行调节.     

2,2′-二邻甲氧基苯基-4,4′,5,5′-四苯基-1,2′-二咪唑复合光引发体系的光聚合动力学研究

本文研究了对2,2′-二邻甲氧基苯基-4,4′,5,5′-四苯基-1,2′-二咪唑(BMOIM)复合光引发体系引发聚合动力学过程.采用紫外光谱仪对引发剂、供氢体、增感剂在紫外区的吸收谱图进行了表征.利用实时红外光谱仪对复合光引发体系引发聚合动力学过程进行实时监测,考察了不同光强、引发剂浓度以及不同官能度单体对反应速率及最终双键转化率的影响.结果表明,在引发剂浓度为0.6%(质量分数)时,20s内双键转换率达到96%,随着引发剂浓度的提高,聚合速率增大.聚合速率以及最终双键转化率随着光强增大而增大;双官能团单体的最终双键转化率比三官能团单体的最终双键转化率要高.     

纳米SiO_2锚固光敏基团引发MMA光接枝聚合研究

对纳米SiO2进行了锚固光引发剂的表面修饰,进而引发甲基丙烯酸甲脂(MMA)光接枝聚合制备有机/无机复合粒子.纳米SiO2粒子首先用氯化亚砜进行表面氯化,再与光引发剂2-羟基-4-(2-羟基乙氧基)-2-甲基苯丙酮(Irgacure2959)反应从而锚固上光引发剂.通过紫外光引发MMA在经过修饰过的纳米SiO2表面上进行表面光接枝聚合.采用IR、TGA和TEM等方法表征了接枝前后纳米粒子的变化,证明了表面接枝物的存在,并研究了不同反应条件对单体转化率、接枝率和接枝效率的影响.研究结果表明,搅拌对接枝过程的影响比较显著.TGA结果显示未搅拌聚合时接枝率只能达到比较小的程度,而在搅拌条件下180min内MMA的接枝率可达到110%.     

紫外光引发Pickering乳液聚合制备中空复合微球的研究

用光引发剂2-羟基-4-(2-羟乙氧基)-2-甲基苯丙酮(IHT-PI 659)对纳米SiO₂表面进行接枝使之兼具两亲性及光引发特性|以该功能性纳米SiO₂为稳定剂构筑O/W(水包油)型Pickering乳液|用紫外光引发处于内油相的甲基丙烯酸甲酯单体聚合, 制备出具有中空结构的SiO₂/PMMA复合微球, 采用傅里叶变换红外光谱(FTIR)、热失重分析仪(TGA)、透射电镜(TEM)及扫描电子显微镜(SEM)对复合微球进行了表征, 并提出了紫外光引发Pickering乳液聚合制备中空复合微球的机理.     

丙烯酸盐与丙烯酰胺共聚制备耐盐性高吸水树脂

以N,N-亚甲基双丙烯酰胺为交联剂,过硫酸铵-亚硫酸钠为引发剂,采用水溶液聚合法合成了耐盐性高吸水树脂-聚(丙烯酸钠-co-丙烯酰胺).研究了单体配比、丙烯酸中和度、引发剂及交联剂用量以及反应温度对常压及加压(1.96×103Pa)下吸盐水(wNaCl=0.009)率的影响.并对其结构进行了表征.该耐盐性高吸水树脂常压和加压下吸盐水率分别为50g·g-1和18 g·g-1,且凝胶强度好.     

微波技术在合成半纤维素高吸水树脂中的研究

首次以粘胶纤维生产过程中产生的半纤维素废碱液为原料,以丙烯酸为接枝单体,过硫酸铵-亚硫酸氢钠为氧化还原引发剂,N,N-亚甲基双丙烯酰胺为交联剂,分别采用常规加热法和微波辐射法制备半纤维素高吸水树脂,并利用红外光谱仪及扫描电子显微镜对树脂的结构和形貌进行了表征。对比分析了两种方法的反应时间及产物吸水性能,结果表明:两种方法均成功合成了半纤维素高吸水树脂,且利用微波辐射技术可显著缩短反应时间,其产物也具有更高的吸水率及吸水速率。     

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。     

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.     

Study of hydration of two cements of different strengths

Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, M_o, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700^oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date.     

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.