硫氰酸盐光度法测定加压氧化钼精矿萃取液中的钼

本研究 采用硝酸-硫酸-磷酸混合酸溶解试样,建立了硫氰酸盐法测定钼精矿加压氧化萃取液中钼含量的测定方法。对试样的分解方法进行了研究,并通过还原剂选择、酸度的影响及显色条件等一系列条件试验,确定出了最佳试验方法。采用本法对试液进行多次测定,相对标准偏差RSD为<小于1％。试验结果表明,该方法有较高的精密度,测定结果准确可靠,现已成功应用于实际生产检测中。     

Synthesis and Structure Investigation of a Novel 3-Dimensional Potassium Supermolecular Compound Based on 2,4-Dinitro Resorcinol

A novel 3‐dimensional potassium supermolecular compound [K(HDNR)(H₂DNR)(H₂O)]_n (H₂DNR?2,4‐dinitro resorcinol) was synthesized and characterized by elemental analysis and FT‐IR spectroscopy. The crystal structure investigated by X‐ray single crystal diffraction shows that [K(HDNR)(H₂DNR)(H₂O)]_n crystallizes with a monoclinic unit cell in the space group P2(1)/c with unit cell dimensions of a=17.648(5) Å, b=12.527(3) Å, c=7.735(2) Å, β=94.33(2)°, V=1705.00(73) ų, Z=4. The structure was refined to the final R=0.0670 and wR=0.0722 for 2022 observed reflections with I>2σ(I). In the compound, potassium cation is assembled into one‐dimensional chains along c‐axis through oxygen atoms from water molecules, and the chains were connected by the bridged HDNR^? anions to form a two‐dimensional net structure. The two‐dimensional nets constructed a three‐dimensional supramolecular architecture via intermolecular hydrogen bonds and N–O···π interaction. Density functional theory (DFT) B3LYP was employed to optimize the structure and calculate energies for three tautomers of HDNR^? univalent anion. Three stable tautomers were located. It was found that the structure (I) with O(1) losing hydrogen atom is more stable than the structure (II) also with O(1) losing hydrogen atom and the structure (III) with O(4) losing hydrogen atom.     

K_3PO_4-催化的β-硝基苯乙烯衍生物与乙酰胺、NBS的区域专一性氨溴加成反应研究

在无水磷酸钾催化下,以乙酰胺（CH3CONH2）和N-溴代丁二酰亚胺（NBS）为氮源和卤素源,丙酮作溶剂,建立了β-硝基苯乙烯双键上的区域专一性氨溴加成反应新体系.该法在室温下,无需惰性气体保护可高收率的获得邻位氨卤加成产物,最高收率可达79%.实验证明,当β-硝基苯乙烯中苯环4-位具有强供电子基团时（如CH3O）,该...     

卡尔-费休滴定法测定有机锌盐药物中水分

采用卡尔-费休滴定法测定有机锌盐药物中水分时,改用甲醇-氨溶液(质量比180比1)作溶剂溶解试样。改进的溶剂利于有机锌盐药物的溶解及结晶水的释放。试验结果表明:有机锌盐药物中水分的测定值比药典法测定值高,相对标准偏差(n=5)在0.13%～0.36%之间。     

自动电位滴定法测定脱硫系统中氯化物

应用自动电位滴定法,在总离子强度缓冲溶液存在的情况下,在pH 5的微酸性水溶液中,用0.05mol·L~(-1)硝酸银标准溶液作为滴定剂,测定了脱硫系统样品中氯化物含量。试样用水浸取溶出氯化物,共存亚硫酸盐的干扰采用在近中性条件下加入过氧化氢煮沸至无小气泡产生予以消除,对试样的预处理方法以及各项影响测定的参数等做了试验并予以优化。方法用于测定脱硫废水、脱硫浆液和脱硫石膏样品中氯化物,加标回收率在95.7%～102.0%之间,相对标准偏差(n=5)在1.2%～5.9%之间。     

EDTA滴定法测定钢渣中游离氧化镁

以碘-乙醇溶液为催化剂,选择乙二醇作溶剂浸取钢渣中游离氧化镁,采用EDTA滴定法测定其中游离氧化镁的含量。试验中考察了碘-乙醇的最佳用量和K-B混合指示剂的最合适配比。结果表明:催化剂碘-乙醇溶液的添加量达碘与氧化镁的质量比为7.5比1,指示剂中酸性铬蓝K和萘酚绿B的比值为1比1.4时,滴定终点变色明显,滴定结果准确。在钢渣中加入纯氧化镁测定的平均回收率为96.5%,相对标准偏差(n=5)为1.3%。     

阻抑高碘酸钾氧化甲基紫褪色光度法测定苯酚

基于HAc-NaAc缓冲体系中,反应温度为25℃时,苯酚阻抑高碘酸钾氧化甲基紫的褪色反应,建立了测定苯酚的阻抑褪色光度新方法.该方法最大吸收波长为580 nm,线性范围为0.02μg/mL～2·2μg/mL,检出限为3.8×10<'-3>μg/mL,方法用于环境水中苯酚的测定,相对标准偏差为1.97%～2.25%,回收...     

Ultrastable Surface-Dominated Pseudocapacitive Potassium Storage Enabled by Edge-Enriched N-Doped Porous Carbon Nanosheets

The development of ultrastable carbon materials for potassium storage poses key limitations caused by the huge volume variation and sluggish kinetics. Nitrogen-enriched porous carbons have recently emerged as promising candidates for this application; however, rational control over nitrogen doping is needed to further suppress the long-term capacity fading. Here we propose a strategy based on pyrolysis–etching of a pyridine-coordinated polymer for deliberate manipulation of edge-nitrogen doping and specific spatial distribution in amorphous high-surface-area carbons; the obtained material shows an edge-nitrogen content of up to 9.34 at %, richer N distribution inside the material, and high surface area of 616 m² g⁻¹ under a cost-effective low-temperature carbonization. The optimized carbon delivers unprecedented K-storage stability over 6000 cycles with negligible capacity decay (252 mA h g⁻¹ after 4 months at 1 A g⁻¹), rarely reported for potassium storage.     

山梨酸钾与Zn2+在NaCl溶液中对Q235钢的缓蚀协同作用

采用失重法、电化学法、X射线光电子能谱(XPS)和扫描电子显微镜(SEM)研究了0.5 mol/L NaCl溶液中,山梨酸钾(PS)与Zn²⁺对Q235钢的缓蚀协同效应。 失重实验结果表明,在0.5 mol/L NaCl溶液中,PS对Q235钢具有一定的缓蚀效果,缓蚀效率随PS质量浓度的增加而增大,当添加PS的质量浓度为25.0 g/L时,最大缓蚀效率仅为38.37%,而PS与Zn²⁺复配后存在显著的缓蚀协同作用,缓蚀效率高达91.03%。 动电势极化结果表明,PS与Zn²⁺混合物可同时抑制Q235钢的阴、阳极反应,属于阳极型缓蚀剂。 阻抗谱表明,该混合物可在电极表面形成致密的保护膜。 XPS分析证明保护膜是由PS、铁的氧化物/氢氧化物和Zn(OH)₂沉淀组成。     

高效液相色谱-四极杆/飞行时间质谱鉴定阿莫西林克拉维酸钾干混悬剂中的未知组分

采用高效液相色谱-四极杆/飞行时间质谱(HPLC-QTOF/MS)建立了阿莫西林克拉维酸钾混悬剂(ACPS)中未知组分的鉴定方法,以BDS Hypersil C18(4.6 mm×250 mm,5μm)为色谱柱,以乙腈-水(0.1%甲酸)为流动相,流速为1 mL/min。比较了中国药典方法和HPLC-QTOF/MS方法的相关性;利用半制备液相色谱收集未知组分,并在HPLC-QTOF/MS体系中进行定位和确认,确定未知组分在液质体系中的出峰位置和准确分子量;筛查混合空白辅料成分,并通过与标准品比对,利用HPLC-QTOF/MS鉴定ACPS的未知组分为糖精钠。方法可为抗生素药品中未知组分的鉴定提供参考。