直链型巯基醇类化合物对Q235钢的缓蚀性能

直链型巯基醇分子具有双头基两亲分子的特殊结构,研究其烷烃链长对缓蚀性能的影响具有十分重要的理论和现实意义。利用腐蚀试验研究了巯基乙醇(C_2)、3-巯基丙醇(C_3)、6-巯基-1-己醇(C_6)和9-巯基-1-壬醇(C_9)4种分子对Q235钢的缓蚀率,结合量子化学从头算和分子动力学模拟方法讨论了链长对其缓蚀性能的影响机理。通过前线轨道分布、Fukui函数和构效关系对分子的反应活性进行了分析,同时在气相条件下模拟缓蚀剂在金属界面的吸附行为。结果表明:4种分子有相同的活性位点,且长链巯基醇分子因带有较多的负电荷、供电子能力强以及在金属表面具有高的吸附能等特点而具有较大的缓蚀率,表现出较高的缓蚀能力。     

ZS曼尼希碱缓蚀剂的制备与性能

为了解决在油气田酸化过程中酸液对地面管路及井筒管壁造成严重腐蚀的问题,合成了一种新型的噻唑类曼尼希碱缓蚀剂来保护金属。通过静态失重法、电化学方法和分子动力学模拟方法研究了该缓蚀剂在15%盐酸腐蚀介质中对N80钢的缓蚀性能。静态失重法表明:在加入1.0%(质量分数)优选配方合成的缓蚀剂ZS的腐蚀介质中N80钢的腐蚀速率为0.412 9 g/(m~2·h),远优于SY 5405-1996中的一级标准。电化学测试表明:该缓蚀剂是以抑制阳极反应为主的混合型缓蚀剂,其在N80钢表面上的吸附行为服从Langmuir吸附等温式,说明缓蚀剂ZS在N80钢上形成了单分子层吸附。分子动力学模拟结果表明:在介质中缓蚀剂分子可以稳定地吸附在金属表面,并有效地将金属表面和腐蚀介质隔开,从而起到缓蚀作用。     

2种四唑衍生物缓蚀剂在碱性介质中对铜的缓蚀性能和吸附行为

有机缓蚀剂能在金属表面发生吸附而降低金属的腐蚀速率,但目前对其在金属表面的吸附机理仍不十分清楚.合成了胍基四唑(GT)和1-(对甲基)苯基-5-巯基-1,2,3,4-四氮唑(MMT)2种缓蚀剂,用失重法和电化学法研究了2种缓蚀剂在5%NaHCO_3碱性介质中对铜的缓蚀性能和吸附行为.结果表明:MMT和GT属于阳极型缓蚀剂,对铜均有很好的缓蚀性能,且MMT的缓蚀效率大于GT;MMT和GT均在浓度为50 mg/L时缓蚀效率最大(90%以上);30～60℃时2种缓蚀剂的缓蚀性能随温度的升高而降低;2种缓蚀荆在铜表面的吸附都服从Langmuir吸附等温式,属于物理吸附.     

噻二唑型缓蚀剂缓蚀性能的研究

利用电化学测试和表面分析技术,研究了2,5-二巯基-1,3,4噻二唑(DMTD)在硫-乙醇溶液中对金属银、铜的缓蚀性能,结合量子化学计算和分子动力学模拟对DMTD在金属表面的吸附行为和缓蚀作用机理进行了分析讨论。结果表明,DMTD在50mg/L的硫-乙醇溶液中,对金属银、铜均起到较好的缓蚀作用。极化曲线结果表明,当缓蚀剂DMTD浓度达到50mg/L时,缓蚀效率可以达到92.3%。表面分析技术表明,缓蚀剂的加入在金属表面形成吸附膜,明显抑制了腐蚀速率。量化计算和分子动力学模拟得到了缓蚀剂分子的活性位点和缓蚀剂在金属表面的吸附形态。     

N,N'-双(2-硫酮基苯骈噻唑基-3-甲基)-正十二胺的缓蚀性能研究

以2-巯基苯骈噻唑、甲醛和正十二胺为原料在微波辐照下合成了N,N'-双(2-硫酮基苯骈噻唑基-3-甲基)-正十二胺(DTBMDA).采用失重法和动电位极化曲线法对合成的缓蚀剂进行了缓蚀性能测试,利用扫描电镜观察了腐蚀试样表面形貌,并对其缓蚀机理进行了初步探讨.结果表明,DTBMDA能够有效抑制饱和CO2环境下N80钢的腐蚀,属于混合型缓蚀剂.DTBMDA能与金属发生多中心吸附,同时能形成致密的疏水性保护膜,从而起到缓蚀作用.     

铁、不锈钢表面自组装膜的表征及其电化学研究

自组装膜(SAMs)是分子在溶液(或气态)中自发通过化学键牢固地吸附在固体基底上而形成的有序分子膜.由于其堆积紧密、结构稳定,因而具有抑止腐蚀的作用.铁在空气中易氧化,表面均有一层氧化铁,且很难处理,因此关于铁和不锈钢金属表面自组装膜的报道较少.在铁金属表面上组装膜主要集中在烷基硫醇体系,由于烷基硫醇的毒性以及自组装膜的不稳定性,如何寻找新型缓蚀剂在铁表面组装受到广泛的关注.通过研究发现咪唑啉衍生物和巯基三氮唑是一种低毒、高效的金属缓蚀剂,对抑制铁在酸性溶液中的腐蚀尤其有效.采用各种表面分析测试手段与理论化学方法,如分子模拟,研究缓蚀剂在金属表面形成自组装膜的作用机理,也是今后发展的一个方向.本文中合成了两种咪唑啉衍生物(IM)及巯基三氮唑缓蚀剂并表征,并测定其在电极表面组装后铁的电化学腐蚀行为及缓蚀效率.同时采用表面分析的方法如扫描电化学显微镜(SECM)、X射线光电子能谱(XPS)、扫描电子显微镜(SEM)和能谱分析(EDS)对金属表面进行了分析,并用分子模拟的方法对可能的吸附形态进行了理论分析,以分子力学为基本方法,主要研究了铁表面自组装体系,探讨了分子层次的吸附构象以及吸附的稳定性,探讨了其缓蚀机理.(1)咪唑啉在铁表面的自组装膜的研究咪唑啉类缓蚀剂是对环境友好的性能优良的缓蚀剂.因其结构的特殊性,含五元杂环、长的烷基链及功能基团的胺基,其中咪唑啉环上的氮易与铁配位,且p-π共轭体系的咪唑啉以及环上引入供电子基团,能增强氮与铁的化学吸附作用.本文用硬脂酸或松香酸与二乙烯三胺减压下加热脱水制得咪唑啉(IM)咪唑啉衍生物.对两种(IM)在铁表面的组装性能进行比较,用电化学的方法对(IM)在铁表面上的自组装进行研究,主要运用电化学阻抗谱和极化曲线的方法测定缓蚀效率.用表面分析的方法如XPS、SEM等对自组装前后表面的组成腐蚀形貌进到了相应的比较,得出IM在铁表面形成了稳定、均匀的SAMs.电化学阻抗测谱测试结果表明,咪唑啉化合物在酸性溶液中对铁具有良好的缓蚀能力.阻抗谱图均表现为较好的单一容抗弧,用等效电路拟合计算的缓蚀效率与极化曲线法测试所得结果基本一致.其实验结论为:电化学阻抗谱和极化曲线的结果表明咪唑啉缓蚀剂自组装膜对铁有较高的缓蚀作用;XPS的结果表明,咪唑啉分子吸附在金属铁的表面形成SAMs.分子模拟的方法预测了IM在铁表面的吸附形态,表明N原子吸附在铁的表面.分子模拟的方法可预测SAMs的吸附构型.SECM给出了SAMs在基底表面的高分辨率的形貌图,根据靠探针感应到的电流大小可定量的表征自组装膜.采用的恒高度模式,针尖Z方向的位置不受反馈控制,X和Y轴的扫描范围是1mm.其工作模式是基底产生/探头收集,以研究发生在探头针尖与基底间隙的化学动力学过程并对表面浓度进行检测.组装IM后对铁基底的溶解有抑制作用,阻碍了电荷转移过程;从线扫描的曲线及面扫描的三维图中可看出组装之后的铁电极比空白的铁电极表面的探头电流更趋向于平和,没有空白铁电极那么大的电流起伏.在铁电极表面形成的SAMs膜对电极在溶液中发生的氧化还原反应起阻碍作用.松香基咪唑啉形成的SAMs膜与硬脂酸咪唑啉形成的SAMs相比,SECM检测的探头法拉第电流更小,表明松香基咪唑啉的SAMs膜对铁有更好的保护作用,抑制了电荷的转移.SECM的结果与电化学交流阻抗谱和极化曲线的实验结果相一致.(2)巯基三氮唑在铁上自组装膜的表征有目的地设计合成了三氮唑类化合物并对其缓蚀性能进行了较系统的研究.巯基三氮唑及其衍生物由于分子中含有多个杂原子(N,S),能提供孤对电子,进入铁原子空的轨道,产生多个吸附中心,通过配位键化学吸附到金属的表面上而形成SAMs.通过对长烷基巯基三氮唑(AAMT)在铁上的SAMs的研究表明AAMT是一种混合型缓蚀剂,且随着组装时间(15min～4h)的延长,缓蚀效率增加.电化学阻抗谱和极化曲线的结果表明,三氮唑缓蚀剂自组装膜对铁有较高的缓蚀效率,且二者的实验结果相一致;XPS的结果表明,三氮唑分子吸附在铁的表面形成SAMs;从SEM的分析得出,在金属铁的表面形成了一层自组装吸附膜,且SAMs膜对铁在硫酸中的腐蚀起到了保护作用,组装前后铁的腐蚀形貌发生了明显的变化.分子模拟的结果表明,咪唑啉分子中的N原子、S原子与铁成键,且五元杂环平铺在金属铁的表面,而长的烷基支链却发生倾斜,疏水基长烷基的存在增加了吸附膜的厚度,从而达到了缓蚀目的.(3)用SEM和SECM对IM在不锈钢表面自组装的初步探讨不锈钢由于其结构的特殊性,含的成分太多,组装比较困难.本文用SEM表征了咪唑啉在不锈钢表面组装后腐蚀形貌的变化,并用SECM法表征了组装前后法拉第探头电流大小的变化.SAMs在电极表面生成了一层"屏障",将电极与溶液中具有氧化还原活性的分子部分屏蔽起来,使得溶液中的氧化还原产物之间的转化不再与裸电极表面一样容易发生.表面形成SAMs,而且该膜改变了原来电极表面的物理与化学特性,对基底有一定的保护作用.     

2种新型含硫曼尼希碱在盐酸中对N80钢的缓蚀性能研究

油井酸化是增加输油流动的重要技术,但酸液会对石油管线造成严重的腐蚀,造成严重的经济损失和安全隐患.为了防止金属在酸性介质中的腐蚀,以甲醛/苯甲醛、苯乙酮和氨基硫脲为基本原料合成了2种含硫曼尼希碱缓蚀剂(HA和HB),采用失重测试、电化学测试对二者在10％盐酸中对N80钢的缓蚀性能进行研究,运用分子动力学模拟从理论上探讨了HA和HB缓蚀剂分子在Fe(001)晶面上的吸附行为.结果 表明:2种缓蚀剂分子对N80钢都具有良好的缓蚀效果且HB缓蚀剂的缓蚀效果优于HA;2种缓蚀剂在N80钢表面的吸附均符合Langmuir吸附等温模型;2种缓蚀剂均为混合抑制型缓蚀剂.     

饱和CO_2油田水中咪唑啉季铵盐在N80钢表面的吸附与其缓蚀性能关系

为了探讨在含饱和CO2油田水中咪唑啉季铵盐在N80钢表面的吸附与其缓蚀性能的关系,以苯甲酸、二乙烯三胺和氯乙酸钠为原料,合成一种咪唑啉季铵盐缓蚀剂。采用红外光谱对合成物结构进行了表征,采用静态失重法、电化学法和形貌观察法研究了其在含饱和CO2模拟油田水中对N80钢的缓蚀性能及吸附行为。结果表明:在模拟油田水中,咪唑啉季铵盐浓度、温度、时间对N80钢缓蚀性能影响显著;咪唑啉季铵盐能在金属表面形成牢固的单分子吸附膜,阻碍腐蚀介质与金属接触;该缓蚀剂属于混合型缓蚀剂,低浓度以阴极控制为主,高浓度以阳极控制为主;该缓蚀剂主要通过在金属表面吸附成膜,改变金属的界面状态而起缓蚀作用,且随着其浓度的提高,缓蚀性能增强。     

高压阳极铝箔扩孔缓蚀剂的试验与理论研究

高压阳极铝箔在扩孔腐蚀溶液中加入缓蚀剂可提高铝箔的扩面效果,本文采用量子化学计算结合失重法、电化学阻抗法、扫描电镜实验,对硫脲、磺胺、油酸咪唑啉抑制铝箔电化学扩孔阶段的全面腐蚀进行理论研究。试验结果表明:油酸咪唑啉分子吸附活性中心集中在咪唑环上,与铝箔表面金属发生交互作用产生吸附,磺胺分子活性吸附中心在苯环以及N,O原子上,硫脲分子的吸附活性中心在S原子上。三种缓蚀剂在铝箔表面的吸附,有效缓解了扩孔时的并孔,提高了铝箔比电容。油酸咪唑啉在铝箔表面的吸附作用强,不容易进入蚀孔内部,对铝箔缓蚀扩面效果最好。     

三嗪二硫醇化合物对铝合金的缓蚀性能

本研究采用失重法研究了三嗪二硫醇类化合物6-N,N-二丁基胺-1,3,5-三嗪-2,4-二硫醇单盐(DBN)在1mol/L盐酸溶液中对铝合金的缓蚀作用,探讨了缓蚀剂浓度、腐蚀时间和溶液温度对缓蚀效率的影响。结果表明,增大DBN浓度会提高其对铝合金的缓蚀效率,而延长腐蚀时间和升高腐蚀溶液温度都会降低其缓蚀效率。腐蚀反应动力学分析表明,添加DBN后腐蚀反应的表面活化能(Ea)增大,使腐蚀反应变得困难,从而起到缓蚀作用。同时,本研究发现DBN分子在金属表面的吸附行为符合Langmuir吸附等温线,吉布斯自由能计算(Gθads=-30.36kJ/mol)表明该吸附过程是自发的,且同时存在着物理吸附和化学吸附。扫描电子显微镜测定结果表明DBN能够有效地抑制铝合金在酸性介质中的腐蚀。     

Synthesis, characterization and evaluation of 1,2-bis(2,4,6-trinitrophenyl) hydrazine: A key precursor for the synthesis of high performance energetic materials

1,2-Bis(2,4,6-trinitrophenyl) hydrazine (3) is one of the precursors in the synthesis of an important energetic material viz., hexanitrazobenzene. The simple and convenient lab scale synthesis of title compound (3) was carried out by the condensation of picryl chloride (2) with hydrazine hydrate at 30–50 °C in methanol based on the lines of scanty literature reports. Picryl chloride was synthesized by the reaction of picric acid (1) with phosphorous oxychloride based on the lines of reported method. The synthesized compound (3) was characterized by IR and ¹H NMR spectral data. Some of the energetic properties of the synthesized compound have also been studied. The theoretically computed energetic properties of the title compound (3) indicated the superior performance in comparison to tetranitrodibenzo tetraazapentalene (TACOT) and hexanitrostilbene (HNS) in terms of velocity of detonation.     

Effect of Preparation Conditions on the Crystallinity of Chemically Synthesized BCNO Nanophosphor

The carbon based boron oxynitride (BCNO) phosphor was synthesized by solid state reaction between boric acid (H3BO3) and melamine (C3H6N6) in the molar ratios of 1:1 and 2:1 respectively at different temperatures up to 1400℃. The composition with molar ratios 1:1 of starting materials is found to be highly crystalline with an average particle size of 38 nm and the lattice constants a=b=0.251 nm and c=0.666 nm. The solid state reaction of boric acid and melamine in the composition 2:1 leads to the formation of compound in the semi-crystalline state under the same conditions of preparation, but its phase cannot be recognised. The X-ray diffraction (XRD) spectra, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) images of BCNO compound confirm the phase, nanometre size and shape respectively of synthesized material. The photoluminescence (PL) spectra of the synthesized BCNO products reveals that the electronic structure of BCNO compound can be controlled by changing the molar ratios of starting materials and heating temperatures. These synthesized compounds are very interesting and important candidate materials for light emitter.     

Synthesis, structural investigation, thermal decomposition mechanism and sensitivity properties of an energetic compound [Cd(DAT)(6)](ClO(4))(2) (DAT=1,5-diaminotetrazole)

An energetic coordination compound [Cd(DAT)(6)](ClO(4))(2) has been synthesized by using 1,5-diaminotetrazole (DAT) as ligand and its structure has been characterized by applying X-ray single crystal diffraction, elemental analysis and FT-IR spectroscopy. The central cadmium(II) cation is coordinated by six N atoms from six DAT molecules to form a six-coordinated and distorted octahedral structure. Di-dimension layer structure was formed and the layers were linked together by the extensive intermolecular hydrogen bonds between DAT ligands and ClO(4)(-) anions. Thermal decomposition mechanism of the title compound was predicted based on DSC, TG-DTG and FT-IR analyses results. The kinetic parameters of the first exothermic process of the title compound were studied by applying the Kissinger's and Ozawa-Doyle's methods. Sensitivity tests reveal that the title compound has sensitive nature.     

One-pot route for preparation of monodisperse CuInS2 nanocrystals

Chalcopyrite copper indium sulfide (CuInS₂) nanocrystals (NCs) were synthesized by a one-pot route and characterized by XRD, TEM, HRTEM, EDS, UV-vis and SPS. The experimental results demonstrated that the CuInS₂ NCs synthesized by metal compound [Sn(acac)₂Cl₂] had good crystallinity, monodispersity and stoichiometric composition. The UV-vis absorption spectra showed the as-synthesized CuInS₂ NCs had fine absorption in the visible light region and the energy band gap was estimated to be 1.58 eV. Moreover, the metal compound could improve the photoinduced charge separation and transfer effect of NCs based on the SPS study. The synthesis strategy developed in this work may be used as a general process for the synthesis of pure or doped chalcogenide NCs, and may have great potential to be applied in high efficiency, yet low cost photovoltaic areas.     

Removal and destruction of endocrine disrupting contaminants by adsorption with molecularly imprinted polymers followed by simultaneous extraction and phototreatment

This study presents a method to regenerate molecularly imprinted polymers (MIPs) used for the selective removal of endocrine disrupting compounds from aqueous effluents. Regeneration was based on solvent extraction under UV irradiation to regenerate the polymer and the solvent while destroying the contaminants. Acetone was selected as the best solvent for irradiation of estrone (E1), 17beta-estradiol (E2) and ethinylestradiol (EE2) using either UVC (254 nm) or UV-vis. A MIP synthesized with E2 as template was then tested for the extraction of this compound from a 2 microg/L loaded aqueous solution. E2 was recovered by 73+/-11% and 46+/-13% from the MIPs and a non-imprinted control polymer synthesized under the same conditions, respectively, after a single step elution with acetone. The irradiated polymers and acetone were reused for an additional extraction-regeneration cycle and showed no capacity decrease.     

柔性环氧灌浆材料的制备与性能研究

采用十八胺与乙二醇缩水甘油醚为原料,制得一种两端为环氧基、中间氮原子上接有长疏水侧链的加成物,再由自制亚胺上剩余的仲胺对加成物进行封端,制备出潜伏型柔性环氧固化剂.并用该固化剂制备出低模量高弹性环氧灌浆材料.通过测定固化物的冲击强度、拉伸强度、断裂伸长率和玻璃化转变温度(Tg),扫描电子显微镜对固化物的断裂面形态分析等...     

A microwave-assisted route for the solid-state synthesis of lead pyrophosphate,Pb<Subscript>2</Subscript>P<Subscript>2</Subscript>O<Subscript>7</Subscript>

In this study, we have developed a new method based on microwave heating for the preparation of lead pyrophosphate compound, Pb₂P₂O₇. The favoring of microwave heating as synthesis technique is based on the fact being much faster, cleaner and economical than conventional techniques. By following this new route, the lead pyrophosphate, Pb₂P₂O₇, was obtained as a pure phase. The products were characterized by X-ray powder diffraction (XRD) and Fourier Transform IR (FTIR) spectroscopic techniques. Comparing the experimental XRD and FTIR data of the synthesized products with the reported literature data has revealed that there was mutually an excellent agreement.     

TiO2-V2O5 nanocomposites as alternative energy storage substances for photocatalysts

TiO2-V2O5 was prepared and evaluated as an energy storage material for photocatalysts with high capacity and initial charging rate. The compound was successfully obtained by sol-gel technique and effects of compound composition and calcination temperature on the energy storage ability were investigated. The synthesized compounds were characterized by means of X-ray powder diffraction (XRD), scanning electron microscopy equipped with energy-dispersive X-ray analysis (SEM-EDX) and transmission electron microscopy (TEM). The results reveals that the compound of Ti:V molar ratio equal to 1:0.11 calcined at 550 degrees C exhibited superior energy storage ability than parent substances and 1.7-times higher capacity and 2.3-times higher initial charging rate compared to WO3, indicating that the compound is a remarkable alternative to conventional energy storage substances.     

Preparation for a new intercalated compound of acrylamide monomers and their in-situ polymerization in layered double hydroxides

A new intercalation compound based on Mg/Al-layered double hydroxide (Mg/Al-LDH) with polymerizable acrylamide (AM) which cannot be synthesized by direct coprecipitation reaction, was achieved via in-situ hydrothermal method with the existence of glycine. The well-crystallized AM-intercalated Mg/Al-LDH was characterized by XRD, FTIR, DTA and scanning electronic microscopy. Basal spacing of the Mg/Al-LDH intercalation compound is 1.32 nm. Polymerization of AM incorporated into Mg/Al-LDH interlayer space occurs after 160 °C heat treatment, which indicates that the preparation of PAM/LDH nanocomposite is feasible via in-situ polymerization route.     

一种桥链DOPO衍生物的合成及对聚乳酸的阻燃性能

以9,10-二氢-9-氧杂-10-磷杂菲-10-氧化物(DOPO)和乙二醇为主要原料,碘化钠为催化剂,设计合成了一种新型的桥链DOPO衍生物(Di-DOPO)。采用红外光谱、差示扫描量热分析、热重分析、质谱分析、核磁共振等方法对其进行分析表征,确定了其结构。将该化合物与聚乳酸(PLA)共混,通过氧指数(LOI)测试、垂直燃烧、热重分析、锥形量热等手段考察了其对PLA的阻燃性能及热降解行为的影响。结果表明,Di-DOPO质量分数达到10%时就可以使阻燃PLA材料通过UL-94 V-0级,并能有效抑制PLA的熔滴现象,LOI值也由纯PLA的20%提升到36.3%。阻燃剂质量分数为5%,10%和15%时,热释放速率峰值(PHRR)分别降低了5.2%,12.7%,19.6%。当加入Di-DOPO后,阻燃PLA复合材料的热稳定性比纯PLA明显提高。综上,所制备的Di-DOPO阻燃剂对PLA具有很好的阻燃效果。