阳离子淀粉接枝絮凝剂的制备研究——淀粉和丙烯酰胺接枝共聚物的胺甲基化反应

研究了淀粉和丙烯酰胺接枝共聚物的胺甲基化反应合成阳离子高分子絮凝剂,试验各种反应条件对胺甲基化反应的影响;并探讨一步法进行该共聚物的胺甲基化反应,胺化度虽略低于二步法,但差别不大,操作简便,同样可制得性能较好的阳离子高分子絮凝剂。     

淀粉基阳离子絮凝剂的研制及性能测试

用可溶性淀粉为原料,通过接枝改性合成了一种淀粉基阳离子絮凝剂(MSF),其最佳制备工艺条件为:淀粉与丙烯酰胺的质量比为1:2,引发剂用量为0.6 g,反应温度为50 ℃,接枝时间为3.5 h;阳离子化条件为:甲醛和二甲胺摩尔比为1.0:1.4,反应时间2.5 h,反应温度50 ℃.产物结构经FTIR证实.用其处理番茄废水后,废水的透光率提高了78.2%、TOC下降了22.5%、COD下降了37.25%,结果表明该产品对高浓度有机废水的絮凝性能优于聚丙烯酰胺高分子絮凝剂(PAM).     

淀粉接枝聚丙烯酰胺阳离子絮凝剂的合成及应用——推荐一个高分子化学综合实验

介绍一个综合化学实验。实验通过淀粉与丙烯酰胺的接枝聚合反应和阳离子化改性,合成了一种新型淀粉接枝聚丙烯酰胺阳离子高分子絮凝剂,进行了结构表征,以人工模拟染料废水和重金属离子废水为实验对象,探究了合成的聚丙烯酰胺、淀粉接枝聚丙烯酰胺和淀粉接枝聚丙烯酰胺阳离子絮凝剂在废水净化中的应用。本实验理论与实践相结合,有助于激发学生的学习兴趣,培养学生的学科交叉融合思维和分析解决问题的能力。     

木质素阳离子絮凝剂的合成及其絮凝性能研究

以酶解木质素、甲醛、二甲胺及阳离子化试剂为原料,制备了木质素基阳离子絮凝剂.改变阳离子化试剂的用量、缩合反应的温度和时间等因素,制备不同阳离子度的木质素阳离子絮凝剂;通过其对酸性黑10B的脱色效果研究,确定了最优的制备方案.利用最优条件制备的木质素阳离子絮凝剂对三种不同种类阴离子染料废水进行了絮凝脱色处理.结果表明,原...     

油田作业废水絮凝过程中Zeta电位的研究

以川中矿区典型的压裂酸化废水为研究对象,考察了溶液pH值、无机混凝剂、有机高分子絮凝剂、以及无机混凝剂与有机高分子絮凝剂共同作用对废水Zeta电位的影响,从理论上对油田废水的絮凝特点进行了表征.实验结果证明:油田作业废水适合在酸性条件下进行絮凝处理;聚硅硫酸铁和阳离子有机高分子絮凝剂能使废水颗粒表面Zeta电位明显正移;当联合使用时,先加无机混凝剂,后加有机絮凝剂,能提高污水处理质量.     

接枝型阳离子淀粉絮凝剂对石材废水的絮凝降浊性能与机理研究

混凝/絮凝工艺是去除废水中悬浮胶体颗粒、降低浊度的有效手段.本研究以一种常见的天然高分子材料——淀粉为原材,以丙烯酰胺和甲基丙烯酰氧乙基三甲基氯化铵为共聚单体,采用接枝共聚技术,开发了一系列接枝链分布相同、但电荷密度及平均接枝链链长不同的接枝型阳离子淀粉改性絮凝剂:淀粉接枝共聚丙烯酰胺-聚甲基丙烯酰氧乙基三甲基氯化铵(St-G).并以一种具有高浊度特征的行业废水——石材废水为研究对象,详细讨论了St-G的结构因素(电荷密度与平均接枝链链长)及环境因素(絮凝剂投加量和pH等)对其絮凝性能的影响,结合絮凝后上清液Zeta电位、絮体结构的动态监测结果以及扩展DLVO(Derjguin-Landau-Verwey-Overbeek)胶体稳定理论等,详细探究了其絮凝机理.研究结果表明, St-G对石材废水的絮凝性能明显优于传统无机混凝剂聚合氯化铝, St-G对石材废水的除浊作用主要是电荷碎片机制为主导,且与黏结架桥作用协同作用的结果.随着St-G电荷密度的增加,其浊度去除率增加而对应最佳絮凝剂用量减少,且絮体破碎后恢复因子增加;而絮体尺寸、絮体生长速度及其破碎因子均与St-G平均接枝链链长呈正相...     

有机-无机杂化高分子絮凝剂PAC-PDMDAAC的合成与表征

以过硫酸铵为引发剂,以乙二胺四乙酸四钠(Na4EDTA)为助剂合成了新型有机-无机杂化高分子絮凝剂聚合氯化铝-聚二甲基二烯丙基氯化铵(PAC-PDMDAAC).实验考查了DMDAAC单体质量分数、引发剂用量、反应温度以及反应时间对杂化絮凝剂合成的影响.结果表明杂化高分子絮凝剂的最佳合成条件为单体质量分数30%,引发剂质量分数0.7%,反应温度60℃,反应时间5 h.傅里叶红外光谱(FTIR)、热重分析(TGA)以及扫描电镜(SEM)测试结果表明,杂化聚合物PDMDAAC链端有—SO42-离子存在,其与带正电荷的羟基铝粒子以离子键形式键合.扫描电镜结果显示杂化絮凝剂具有更大的比表面积,易于发挥吸附架桥作用.采用Al-Ferron逐时络合比色法研究絮凝剂中Al形态,结果表明杂化絮凝剂中Alc部分,即不与Ferron发生络合反应的高聚物明显增多.由PAC、复配型PAC-PDMDAAC和杂化型PAC-PDMDAAC絮凝剂分别处理腐植酸-高岭土模拟水样和长江水,结果表明杂化型絮凝剂在浊度和UV254的去除率上优于其它二者.     

PAM-Fe(OH)3有机-无机杂化型高分子絮凝剂的合成及表征

在水溶液中以过硫酸铵((NH4)2S2O8)和亚硫酸氢钠(NaHSO3)为引发体系,利用原位聚合法合成了聚丙烯酰胺(PAM)-氢氧化铁(Fe(OH)3)有机-无机杂化型高分子絮凝剂.通过正交实验得到合成杂化絮凝剂的最佳条件为:反应温度40℃,引发剂质量分数0.5%,丙烯酰胺质量分数30%,反应时间7 h.FT-IR、T...     

有机阳离子高分子絮凝剂

近年来,有机阳离子高分子絮凝剂得到国内外学者的广泛重视.它的研究、开发、应用都取得了显著进展.本文对此进行评述和介绍,内容涉及阳离子型聚丙烯酰胺接枝共聚物、羟基醚化类、二烷基二烯丙基卤化铵类和环氧氯丙烷与胺反应物,特别是近年来淀粉等天然高分子改性阳离子型絮凝剂和人工合成的无毒有机阳离子高分子絮凝剂.     

脱氢枞胺键合交联聚苯乙烯树脂的制备

运用高分子反应法，制备脱氢枞胺键合交联聚苯乙烯树脂，反应分三步进行：醚化反应，双键环氧化和脱氢枞胺与环氧基开环反应，探讨了每一步合成的最佳工艺条件，通过红外光谱对该功能高分子进行了结构表征，并对该合成产物进行对映体分离的初步应用。     

Pyrolysis studies of aromatic polyesters

The products of pyrolysis, at 400°C in vacuo (1 Pa), of poly(ethyleneterephthalate) (PET) and poly(butyleneterephthalate) (PBT) were studied. The products were identified by gas chromatography/mass spectrometry technique. The highly volatile products of PET contained acetaldehyde, benzene, toluene, styrene and ethylbenzene and in the case of PBT, butadiene, tetrahydrofuran, vinylcyclohexene and ethylbenzene were the major products. A qualitative analysis of the products of low volatility revealed that the main components were benzoic acid, terephthalic acid, monovinyl esters of terephthalic acid and higher oligomers in the case of PET, whereas benzoic acid, monobutenyl esters of terephthalic acid and higher oligomers were the main products from PBT. The results obtained were in good agreement with those obtained from pyrolysis experiments, carried out directly in the mass spectrometer. Mechanisms to explain the occurrence of the different products are proposed.     

The gas-phase ozonolysis of α-humulene

α-Humulene contains three double bonds (DB), and after ozonolysis of the first DB the first-generation products are still reactive towards O(3) and produce second- and third-generation products. The primary aim of this study consisted of identifying the products of the three generations, focusing on the carboxylic acids, which are known to have a high aerosol formation potential. The experiments were performed in a 570 litre spherical glass reactor at 295 K and 730 Torr. Initial mixing ratios were 260-2090 ppb for O(3) and 250-600 ppb for α-humulene in synthetic air. Reactants and gas-phase products were measured by in situ FTIR spectroscopy. Particulate products were sampled on Teflon filters, extracted with methanol and analyzed by LC-MS/MS-TOF. Using cyclohexane (10-100 ppm) as an OH-radical scavenger and by monitoring the yield of cyclohexanone by PTR-MS, an OH-yield of (10.5 ± 0.7)% was determined for the ozonolysis of the first DB, and (12.9 ± 0.7)% of the first-generation products. The rate constant of the reaction of O(3) with α-humulene is known as k(0) = 1.17 × 10(-14) cm(3) molecule(-1) s(-1) [Y. Shu and R. Atkinson, Int. J. Chem. Kinet., 1994, 26, 1193-1205]. The reaction rate constants of O(3) with the first-generation products and the second-generation products were, respectively, determined as k(1) = (3.6 ± 0.9) × 10(-16) and k(2) = (3.0 ± 0.7) × 10(-17) cm(3) molecule(-1) s(-1) by Facsimile-simulation of the observed ozone decay by FTIR. A total of 37 compounds in the aerosol phase and 5 products in the gas phase were tentatively identified: 25 compounds of the first-generation products contained C13-C15 species, 9 compounds of the second-generation products contained C8-C11 species, whereas 8 compounds of the third-generation products contained C4-C6 species. The products of all three generations consisted of a variety of dicarboxylic-, hydroxy-oxocarboxylic- and oxo-carboxylic acids. The formation mechanisms of some of the products are discussed. The residual FTIR spectra indicate the formation of secondary ozonides (SOZ) in the gas phase, which are formed by the intramolecular reaction of the Criegee moiety with the carbonyl endgroup. These SOZ revealed to be stable over several hours and its formation was shown not to be affected by the addition of Criegee-radical scavengers such as HCOOH or H(2)O. This suggests that in the ozonolysis of α-humulene at atmospheric pressures the POZ will decompose rapidly, and that a large fraction of the formed exited Criegee Intermediate will be stabilized to form stable SOZ, while the formation of OH-radicals via the hydroperoxide channel will be a minor process.     

Mo-V-Nb多组元氧化物催化乳酸氧化脱氢反应制备丙酮酸

丙酮酸是一种重要的有机合成和药物合成中间体,本文采用成本低廉的乳酸为原料,以Mo-V-Nb多组元氧化物为催化剂,在较低的反应温度下催化氧化脱氢合成了具有高附加值的丙酮酸。应用X射线衍射（XRD）和扫描电子显微镜（SEM）表征了Mo-V-Nb多组元氧化物的物相组成和微观结构,采用气相色谱质谱联用（GC-MS）分析了反应产物,研究了乳酸氧化脱氢可能的反应路径,并深入探讨了关键反应参数反应温度、氧气分压和质量空速对催化选择性和乳酸转化率的影响。     

烟草中两种紫罗兰醇葡萄糖苷衍生物的分离鉴定及热分析研究

采用传统柱层析技术和高效液相色谱相结合的方法从烤烟中分离出3-氧代-α-紫罗兰醇-β-D-吡喃葡萄糖苷和7,8-二氢-3-氧代-α-紫罗兰醇-β-D-吡喃葡萄糖苷,利用ESI MS、1H NMR、13C NMR进行结构鉴定。为开发热稳定型香原料,在300、600、900℃及氦气环境中对2种糖苷进行了在线热裂解(Py)研究和释香机理讨论,研究表明主要裂解物为烟草重要香味物巨豆三烯酮及其同分异构体和3-氧代-α-紫罗兰醇。首次对3-氧代-α-紫罗兰醇-β-D-吡喃葡萄糖苷进行了热重-红外-气相色谱-质谱联用分析,在265℃时,目标物巨豆三烯酮及其同分异构体快速脱落。该技术不仅方便快速,还能实时地对裂解产物进行鉴定,为天然产物的裂解产物在线分离和鉴定提供了依据。     

Combustion of poly(1-methyl hexamethylene) and poly(1-methyl tetramethylene) and identification of the main decomposition products

The Bayer-ICI-Shell apparatus has been used to carry out combustion experiments on poly(1-methyl hexamethylene) (PH) and poly(1-methyl tetramethylene) (PT) using different air flow rates at various combustion temperatures. The products were adsorbed on charcoal followed by benzyl-alcohol desorption. They were separated and identified using gas chromatography.The non-oxidized products were identified as short chain, saturated and unsaturated hydrocarbons while the main oxidized products are short chain ketones and alcohols. The intensities of the chromatographic peaks of the separated products depend upon the temperatures and air flow rates in the combustion apparatus.     

Thermal analysis of blends of low density polyethylene, poly(ethyl acrylate) and ethylene ethyl acrylate copolymer with polydimethylsiloxane

The thermal stability of blends of polyethylene, poly(ethyl acrylate) and ethylene ethyl acrylate (EEA) copolymer with polydimethylsiloxane has been investigated in inert atmosphere using TG-DTC and TVA. The condensable volatile degradation products from the TVA experiments were separated by subambient TVA and investigated by FT-IR spectroscopy, GC., MS and GCMS techniques. The cold ring fraction was characterised by FT-IR spectroscopy and GC. Most of the degradation products from the blends were similar to the degradation products from polydimethylsiloxane and the corresponding polyolefin when degraded alone, but the presence of some additional products indicated interactions during degradation as a result of blending. The mechanisms of formation of degradation products from the blends are discussed in detail.     

无溶剂下位阻控制的Biginelli反应

在NaHSO4作催化剂, 无溶剂下将水杨醛、活泼亚甲基化合物和尿素或硫脲进行Biginelli 反应, 高收率地合成了一系列monastrol类物质. 产物的结构通过IR, 1H NMR, 13C NMR光谱数据和单晶解析表征和确定. 对于不同活泼亚甲基化合物参与的反应, 形成了4-(2-羟基苯基)嘧啶衍生物2和氧桥嘧啶衍生物3两类物质, 活泼亚甲基化合物分子中醇酯基的结构是决定两种嘧啶衍生物结构的主要因素. 对于以前报道的Biginelli产物4-(2-羟基苯基)嘧啶衍生物2a和氧桥嘧啶衍生物3e的形成也进行了讨论.     

高效液相色谱-电喷雾质谱联用研究三氯生的光聚合产物

三氯生在光解时可能会产生二噁英类物质,因而它在日用化学品中的安全性受到学术界的广泛关注.本文采用高效液相色谱-电喷雾质谱研究了三氯生在紫外光照射下的光聚合反应,通过对产物的准分子离子分析,初步确定了7种光聚合产物.聚合物的分子离子分别为505、540、792,且有同分异构体存在,其异构体个数分别为2个、3个和2个.这些物质的产生主要由三氯生分子间脱除氯化氢、分子上脱除氯离子等过程来聚合完成.在光解溶液中也测到2,8-二氯代二苯并-对-二噁英,该物质则是通过分子自身脱除氯化氢而环化产生.同时应用液相色谱定性分析了不同光源对光聚物产生及含量变化的影响.结果表明,三氯生的光聚合反应受光源的影响显著,UVB比UVA更易产生聚合反应.     

Determination of amitraz and its degradation products and monitoring degradation process in quince and cucumber

Amitraz is a non-systemic acaracide and insecticide. Current maximum residue limits for amitraz are stated as ‘Amitraz including the metabolites containing the 2,4-dimethylaniline moiety’. Therefore, determination of amitraz and its all degradation products are important. In this study, we develop a gas chromatography/mass spectrometry (GC/MS) method for determination of amitraz and its degradation products 2,4 dimethylaniline (DMA), 2,4 dimethylformamidine (DMF) and N-(2,4-dimethyl phenyl)-N’-methylformamidine (DMPF) in cucumber and quince. The mechanism of the degradation process was monitored at different temperatures. Amitraz and its degradation products were extracted using the QuEChERS method. To determine amitraz and its degradation products, we used GC/MS. Quantification was carried out by using selected ion monitoring, and total ion chromatogram was used to monitor additional degradation products. The method was validated by studying linearity, limit of detection (LOD) and limit of quantification (LOQ), recovery and precision. The mechanism of the degradation process was monitored at different temperatures. Degradation of amitraz mainly to three degradation products, namely DMA, DMF and DMPF, increased with temperature. Besides these three main degradation products, two other new degradation products were detected.     

Identification of leucine-enkephalin radical oxidation products by liquid chromatography tandem mass spectrometry

The oxidation of the peptide leucine-enkephalin (YGGFL) induced by the hydroxyl radical (HO*), formed under Fenton-like conditions [Cu (II)/H(2)O(2)], was studied and monitored by LC-MS. The oxidation products identified included products resultant from (a) the insertion of oxygen atoms (1-5), (b) peptide backbone cleavage (short-chain products formed by diamide pathway) and (c) radical-radical crosslinking reactions. In order to identify the modified residues, LC-MS/MS spectra were obtained. The insertion of oxygen atoms into the peptide originated hydroxide, di-hydroxide and/or hydroperoxide derivatives. In addition it was found that the aromatic amino acids are most susceptible to being hydroxylated, while the aliphatic amino acids are more prone to forming hydroperoxides. Oxidation products with double bonds were also identified. The short chain products resulted from the alpha-carbon radical of terminal amino acids (Tyr and Leu). Products resulting from cross-linking reactions between intact carbon-centered peptide radical (with and without one HO group) and a side chain radical (*C(7)H(7)O) were identified. It was found that, although all amino acids residues of the peptide undergo modifications, the N-terminal seems to be prone to oxidative modifications under these conditions.