三草酸合铁(Ⅲ)酸钾制备实验的探究

在三草酸合铁(Ⅲ)酸钾制备实验中,对投料比、草酸的加入方式、溶液的pH及反应温度等方面进行了探究,通过优化实验过程,提高了产率和实验教学效果,同时培养学生的环境保护意识.     

三草酸合铁(Ⅲ)酸钾的合成方法研究

三草酸合铁(Ⅲ)酸钾的制备实验是很多大学在大一学生中开设的综合设计实验。许多高校对此实验的操作条件进行了研究与改进,本文从原料、原理、加量、加速等实验条件方面分析比较了三草酸合铁(Ⅲ)酸钾的几种合成方法,并对这些方法的优点和缺点进行了归纳总结。     

三草酸合铁(Ⅲ)酸钾合成工艺的优化

以硫酸亚铁铵、草酸为主要原料,双氧水为氧化剂合成三草酸合铁(Ⅲ)酸钾。采用响应面法优化三草酸合铁(Ⅲ)酸钾的制备工艺,用XRD、FT-IR、SEM对产物进行表征。结果表明,产物化学式为K[Fe(C_2O_4)_3]·3H_2O,形貌为微米块状颗粒。优化工艺条件:草酸亚铁制备中草酸用量为28.00 m L、反应时间为18.00 min;氧化配位反应中草酸钾用量为17.00 m L、H_2O_2用量为6.00 m L,清除H_2O_2时间为5.00 min;酸溶配位中草酸用量为11.00 m L,在该条件下重复实验,产品均为翠绿色晶体,产率均在89.89%~90.57%之间。     

三草酸合铁(Ⅲ)酸钾制备新方法的探讨及其条件优化

本科无机化学实验教学中的经典教学案例—“三草酸合铁(Ⅲ)酸钾(K3[Fe(C2O4)3]·3H2O)的制备”是通过“酸法”反应来实现的。但酸法制备有诸多缺点：副反应多、条件难以控制、产物含杂质等。为此,尝试开发新的实验方案以替代现有方案。新方案以硫酸亚铁铵、过氧化氢和氨水为起始反应物,通过“碱法”反应制得产物,再将产物结晶析出。新方案避免了传统制备方法的缺点,所得产物晶型好、纯度高、产率高且易于制备。为完善新实验方案,本实验还重点探讨了各关键因素的变化对产物形成的影响,初步分析了同一因素在过量、适量和不足条件下的对应产物,有助于优化实验条件以达到提高产物纯度和产率的目的,为下一步的定性定量分析做好准备工作。     

三草酸合铁（Ⅲ）酸钾的制备实验的探索与改进

针对无机化学实验-三草酸合铁（Ⅲ）酸钾制备实验中存在的问题,对K3[Fe（C2O4）3]·3H2O的制备条件进行探索和改进。改进后的制备条件不仅改善了实验结果的重现性,也提高了产品的产率和纯度。     

寡聚酸合铁（Ⅲ）制备工艺的研究

以寡聚酸和三氯化铁为原料,研究了不同的反应体系pH值和配位比对寡聚酸合铁（Ⅲ）合成及其水解稳定性的影响,并且用红外光谱分析对寡聚酸合铁（Ⅲ）的结构进行了表征。试验结果表明：经过单因素试验,确定出反应的最佳pH值为6,最佳配位比为：寡聚酸／铁＝1：16。将纯化后的产品做红外光谱分析,并和纯品寡聚酸的红外光谱做了比较,证明寡聚酸合铁（Ⅲ）成螯合状态。     

酞酸二丁酯在铁(Ⅲ)-草酸盐配合物体系中的光降解

在铁(Ⅲ)-草酸盐配合物体系中考察pH值,铁(Ⅲ)／草酸盐(Fe(Ⅲ)／Ox)配比,酞酸二丁酯(DBP)初始浓度对DBP光降解的影响,结果表明pH=3．5和Fe(Ⅲ)／Ox配比为10．0／120．0μmol／L时具有较强的氧化能力,其光解反应符合表观一级反应动力学规律。并且利用气相色谱-质谱联机分析确定DBP光降解得中间产物,揭示DBP光降解的主要反应途径是OH自由基提取烷基上与羧基相连的α-H,生成醇(ROH),再分解成为酞酸和二醇,进一步氧化脱羧,直至矿化。     

寡聚酸合铈(Ⅲ)的合成及抗氧化作用的研究

在水-乙醇介质中,以寡聚酸钾与硝酸铈反应,合成寡聚酸合铈(Ⅲ)配合物,采用正交实验,考察了V水∶V乙醇、反应温度、反应时间对螯合反应的影响。结果表明,最优反应条件为:V水∶V乙醇=1∶3;温度50℃,时间6 h。通过红外光谱、紫外光谱和差热-热重分析测试手段对配合物进行了表征。红外光谱和紫外光谱均显示,Ce3+与寡聚酸配位,寡聚酸合铈(Ⅲ)配合物中金属配位方式为双齿配位。抗氧化作用研究表明,寡聚酸钾和寡聚酸合铈(Ⅲ)配合物均具有抗氧化活性,配合物与寡聚酸钾相比,对.OH有更高的清除活性。     

二氯化六氨合镍的制备、组成和性质的测定

介绍了由硝酸镍制备二氯化六氨合镍(Ⅱ)的原理和方法,掌握配合物的组成分析、结构确定及验证实验式的方法,学习化学分析、磁化率测定、紫外-可见光谱在测定物理性质中的应用,使学生对综合化学实验有一个感性的认识。     

螺旋藻多糖铁(Ⅲ)配合物的制备、抗氧化及淋巴细胞增殖活性

以三氯化铁为原料,通过络合反应,对螺旋藻多糖(SP)进行结构修饰,制得有机铁化合物〔螺旋藻多糖铁(Ⅲ)配合物SP-Fe(Ⅲ)〕。采用FTIR、DSC、TGA、XRD和SEM对其结构进行了表征,采用DPPH(1,1-二苯基-2-三硝基苯肼)自由基法、羟自由基法等5种方法和MTT(四唑盐)法分析了SP和SP-Fe(Ⅲ)的抗氧化活性和淋巴细胞增殖活性的影响。制备的SP-Fe(Ⅲ)中Fe(Ⅲ)质量分数为16.42%±1.17%。采用5轴蛛网图对SP-Fe(Ⅲ)的抗氧化活性进行了综合评价。结果表明,SP-Fe(Ⅲ)相比SP具有较高的抗氧化活性。在模拟人工胃液消化后,随着消化时间的延长,在pH=6.8的人工肠液中释放出的Fe(Ⅲ)质量分数达到83.64%;在31.25×10–3 g/L的质量浓度下,与SP相比,SP-Fe(Ⅲ)配合物对淋巴细胞增殖提高了44.35%。     

水基光敏树脂的合成

以还氧树脂、丙烯酸、马来酸酐为原料 ,研究了原料投料比、反应温度、催化剂、溶剂等因素对合成水基光敏树脂性能的影响。当丙烯酸酸当量 /还氧当量 =1 0 0∶1 0 5,马来酸酐酸酐当量 /还氧当量 =1 0 0∶1 0 5,催化剂用四甲基氯化铵 ,酸改性溶剂为丙酮 ,反应温度为 80± 2℃ ,反应时间为 2 5h情况下 ,合成的水基光敏树脂水溶性较好 ,以其配制的水性涂料 ,含水在 1 0 %～ 2 0 % (质量分数 )时 ,涂料的涂布性能好 ,固化速度快 (2～ 3s)。     

Synthesis and characterization of photosensitive copolysiloxaneimides

Photosensitive copolysiloxaneimides were prepared by adding a photosensitive monomer such as hydroxyethylacrylate (HEA) to copolyisoimides, which were synthesized by the copolycondensation of pyromellitic dianhydride, benzophenone tetracarboxylic dianhydride with oxydianiline, and bis(p-aminophenoxy) dimethylsiloxane. The forming process of isoimide rings caused by the reaction of polyamic acid with dicyclohexylcarbodiimide and the disappearance process of isoimide rings caused by the reaction of copolyisoimide with HEA were monitored in situ by infrared approach. A series of photosensitive copolysiloxaneimides films were prepared, and the desired structure-properties relationships about inherent viscosities, thermal expansion coefficient, thermal stability and glass transition temperature, dielectric constants, moisture absorption, and photosensitivity were also discussed. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 1463–1468, 1997     

聚冠醚用于金的分离,富集与测定

报道了以新的双酚Ａ型聚冠醇为交换柱的固定相,分离,富集和测量微量金的方法。该法操作简单,结果满意。     

Methodology for material property determination

Predicting solid material pyrolysis requires numerous parameters/properties that are time consuming and difficult to measure. Multiobjective optimization techniques have been used to determine these parameters; however, a methodology for the types of tests needed for the optimization and parameters that should be optimized versus measured has not been fully established. This study investigated combinations of testing protocols and parameters for optimization to determine a testing and optimization methodology that results in the accurate parameters. A Shuffled Complex Evolution (SCE) optimization routine was used to determine parameters based on some parameters being known (ie, measured) and others being determined through optimization and different combinations of types of input data. The results indicate that material testing should be done at three different heating rates in a thermogravimetric analyzer (TGA) and at three different heat fluxes in the cone calorimeter. The TGA tests and two cone calorimeter tests are input into the SCE optimization routine to determine the remaining parameters. The third cone calorimeter test is used to validate the parameters determined using the methodology. The method provides parameters within 20% of the actual parameters input into the Fire Dynamics Simulator (FDS) virtual experiment models. This method is applied to Polymethyl methacrylate (PMMA) experimental data to prove effectiveness.     

复混肥中钾含量检测方法的改进

对GB/T 8574—2010中钾的测定方法进行部分改进,在一定程度上简化了样品的测定程序并缩短了样品测定时间。改进实验过程中称取适量试样直接置于250 m L异颈量瓶(耐热),加适量水,加热煮沸15 min;抽滤后沉淀在180℃条件下烘干45 min。本改进方法检测结果与严格按照国标法检测的结果进行t检验,分析结果无显著性差异,可在复混肥料生产钾检测过程中使用。     

准水溶性光敏环氧酚醛树脂的合成

用二甲苯胺取代溴化季胺盐作催化剂、用甲苯部分取代二氧六环做溶剂合成了准水溶性丙烯酸改性光敏酚醛树脂。实验发现,含31％（质量分数）二氧六环的混合溶剂体系有利于反应的进行,当n（环氧基）:n（丙烯酸）:n（羧基）=50∶50∶49时,其树脂能溶于1％的碳酸钠溶液;当交联体系中活性稀释剂的碳碳双键数与树脂中碳碳双键数相近、m（树脂）∶m（马来酸酐）=239∶1时,漆膜的性能最佳,可耐温230℃并具有其他优良性能。     

火焰光度法快速测定钾肥中的钾含量

通过优化钾肥样品前处理条件,建立火焰光度法快速测定不同钾肥中钾含量的方法。样品经研磨、加水溶解、加热煮沸、定容、干过滤、稀释后,直接用火焰光度计测定。结果表明,火焰光度法的加标回收率为95.0%~103.0%,RSD为0.18%~0.50%,能够满足分析检测要求。此方法简便快速、准确可靠,可用于钾肥中钾含量的测定。     

不锈钢常见成分的联合快速测定

以盐酸 -硝酸混合酸一次性溶样 ,然后对部分试液一次性冒烟处理 ,实现了不锈钢中 Si、Ti、 Mo、 P、 Ni、 Mn、 Cr、 V等 8种成分的联合测定。测定方法简便、快速 ,测定结果令人满意。     

Synthesis and characterization of alkali‐soluble photosensitive polysiloxane urethane acrylate

A new negative temperature coefficient of resistor (NTCR) thermistors based on nitrile butadiene rubber/magnetite (NBR/Fe₃O₄) nanocomposites were successfully fabricated by conventional roll milling technique. X‐ray diffraction and transmission (TEM) analysis showed that the product is mainly magnetite nanoparticles with diameter of 10‐13 nm. The microstructure of (NBR/Fe₃O₄) nanocomposites were examined by scanning electron microscopy (SEM) and FTIR spectroscopy. The dispersion of magnetite nanoparticles in the NBR rubber matrix and interfacial bonding between them were rather good. The thermal stability of nanocomposites was also obviously improved with the inclusion of the magnetite nanoparticles. The thermal conductivity, thermal diffusivity and specific heat of nanocomposites were investigated. The electrical conductivity of the NBR/Fe₃O₄ increases with the rise in temperature exhibiting a typical negative temperature coefficient of resistance (NTCR) behavior like a semiconductor. The nature of the temperature variation of electrical conductivity and values of activation and hopping energy, suggest that the transport conduction process is controlled by hopping mechanism. Values of characteristics parameters of the thermistors like thermistor constant, thermistor sensitivity and thermistor stability is quite good for practical application as NTCR devices at high temperature. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011