浓度对硫酸性质影响的实验研究

通过实验研究了浓度对硫酸性质的影响,结果表明浓度大于等于12 mol·L-1（72%）的硫酸具有明显的吸水性、脱水性、强氧化性和能使铁、铝钝化。浓硫酸与常见指示剂作用颜色变化有各自的变色特点,和常见酸与指示剂作用的颜色变化规律不同。     

硫酸浓度对蛇纹石中氧化镁浸出反应速率的影响

硫酸浸出;动力学;硫酸浓度对蛇纹石中氧化镁浸出反应速率的影响     

虞和钦与中国首家“完全国货”的民办硫酸厂

虞和钦是清末和民国时期脱胎于中国传统士人，致力于科学中国化实践的新型知识分子。论文介绍了虞和钦在筹建开成造酸厂、为开成造酸公司筹资、硫酸试产与投产等方面的作为，指出他作为中国一家曾制衡外商外企的民族硫酸企业之首倡者，理应载入中国近代化学工业的史册。     

Potassium Vanadates of Mixed Valence as Sulfuric Acid Catalyst Precursors

The kinetics of hydrolytic precipitation of potassium vanadates K_xV₁₂O_31-δ ·nH₂O(0 < x ≤ 2.25; 0 <δ ≤ 1.15) from a KVO₃ solution at pH = 1.7 and 80°C in the presence of K₂SO₄ and VOSO₄ is controlled by second and third order reactions respectively occurring on the precipitate surface. This difference is due to the effect of VO²⁺ ions on the polymer anion [V₁₂ O_31-δ]ⁿ formation. Potassium vanadates K_xV₁₂O_31-δ ·nH₂O and K_xV₃O_8-δ·nH₂O (1.02 ≤ x ≤ 1.91; 0 ≤ δ ≤ 0.22) can be used as vanadium-containing precursors for sulfuric acid catalysts. This revised version was published online in June 2006 with corrections to the Cover Date.     

High-yield Carbonization of Cellulose by Sulfuric Acid Impregnation

The carbonization of cellulose with sulfuric acid impregnation was studied by thermogravimetric analysis and scanning electron microscopy. The mass yield of carbon after 800°C treatment in nitrogen increased to 2–3 times by addition of small amounts of sulfuric acid. The sulfuric acid is considered to work as dehydration catalyst, thus suppressing the release of volatile organic substances. The shrinkage of the sample during carbonization was also significantly reduced by the addition of sulfuric acid.     

Vapor—phase Nitration of Benzene to Nitrobenzene over Supported Sulfuric Acid Catalyst

Nitrobenzene is an important chemical intermediate for producing dyestuffs. It is also used as a solvent. The industrial synthesis of nitrobenzene has been carried out in liquid phase with a mixture of nitric acid and concentrated sulfuric acid. This conventional nitration process still has some unsolved problems such as treatment of waste sulfuric acid and disposal of wastewater. The vapor-phase nitration of benzene to prepare nitrobenzene over the solid acidic catalysts in diluted nitric…     

紫外分光光度法测定硫酸中的氮氧化物

建立了使用紫外分光光度法测定硫酸中氮氧化物的方法。利用高锰酸钾将试样中的亚硝酸根氧化成硝酸根,然后在硫酸(30%)介质中,于210nm波长处定量测定试样中氮氧化物的含量。方法检出限为0.0000075%,线性相关系数(r)为0.999 0,平均加标回收率为97.2%~102.8%,平均相对标准偏差(RSD,n=6)为2.9%~3.1%。方法灵敏度高、检出限低,操作简便、成本低,可应用于蓄电池电解液中氮氧化合物的检测。     

Silica Sulfuric Acid as an Inexpensive and Recyclable Solid Acid Catalyzed Efficient Synthesis of Quinolines

Summary. Silica sulfuric acid as an inexpensive and recyclable solid acid efficiently catalyzes the Fridedl?nder synthesis of quinolines through a condensation reaction of a 2-aminoaryl ketone with an activated α-CH acid compound under solvent-free conditions in high yields at 100°C.     

Anodic Oxidation of Silver Alloys in Concentrated Sulfuric Acid Solutions

Anodic oxidation of Ag–Cu and Ag–Pd alloys in concentrated sulfuric acid solutions is studied by cyclic voltammetry. Influence of electronegative (Cu) and electropositive (Pd) constituents on the rate and mechanism of the silver electrooxidation in non-steady-state conditions is revealed. The maximum silver oxidation current increases with the copper content due to a decreased H₂SO₄ concentration in the near-electrode layer and increased solubility of passivating phase Ag₂SO₄. The mechanism of ionization of palladium-doped silver is complicated by two electrochemical reactions involving the formation of Ag₂SO₄ and Ag⁺ _solv.     

硫酸颜色反应用于荧光法测定利血平研究

提出了硫酸颜色反应用于利血平的荧光分析新方法。利用血平与浓硫酸反应，生成强荧光物质，所得产物的荧光强度与利血平的浓度在０－０．６μｇ／ｍＬ范围内有良好的线性关系。检测限为０．２ｎｇ／ｍＬ。本法可直接用于尿液中利血平的定量分析，回收率为８２．５％－８４．２％。     

Xanthan Sulfuric Acid: An Efficient and Recyclable Solid Acid Catalyst for Pechmann Condensation

In this report, substituted coumarins are formed via Pechmann condensation using various substituted phenols and ethyl acetoacetates in the presence of xanthan sulfuric acid as a solid acid catalyst under solvent-free conditions. This method is very simple, cost-effective, and has shorter reaction times, and the catalyst could be reused.     

A Novel Method for Beckmann Rearrangement of Oximes with Silica Sulfuric Acid under Mild Condition

The conversion of ketoxime into corresponding amide, known as the Beckmann rearrangement, is a common method used in organic chemistry and is also a topic of current interest. It accomplishes both the cleavage of carbon-carbon bond and the formation of a carbon-nitrogen bond, and represents a powerful method particularly for manufacture ε-caprolactam in chemical industry. This reaction, however, generally requires high reaction temperature, strong Br?nsted acid and dehydrating media, causing …     

Application of an Electrostatic Precipitator for Instrumental Sampling of Sulfuric Acid

Abstract

A means of separating gaseous sulfuric acid from flue gas particles has been evaluated. Previous attempts to achieve this separation by filtration resulted in retention of the acid by the particulate buildup on the filter surface. By conducting a laboratory study of a prototype electrostatic precipitator, followed by actual flue gas sampling, it was found that the precipitator may eliminate the need for a filter without affecting the measurement results. It was also found that the precipitator could be used prior to a prototype acid monitor for the successful continual monitoring of H₂S0₄ in combustion gases.     

硫酸颜色反应用于乙酰螺旋霉素的同步荧光法测定

提出了硫酸颜色反应用于乙酰螺旋霉素的荧光法测定的新方法。乙酰螺旋霉素本身为弱荧光物质，与沈硫酸反应后生成强荧光物质。以Δλ＝１６ｎｍ进行同步扫描，所得的同步荧光光谱在４９０ｎｍ处的荧光强度与乙酰螺旋霉素的浓度在２０μｇ／Ｌ￣７ｍｇ／Ｌ的东南人线性关系良好。方法的检测限为７μｇ／Ｌ。本法可直接用于尿液中乙酰螺旋霉素的定量分析，回收率为８３．３％￣８８．７％。     

A Modified and Practical Synthetic Route to Indazoles and Pyrazoles Using Tungstate Sulfuric Acid

Tungstate sulfuric acid‐catalyzed Knorr reaction have been used as a simple, rapid, atom economic and green method for the synthesis of indazole and pyrazole derivatives based on the condensation of hydrazine derivatives and ß‐dicarbonyl compounds under solvent‐free conditions. It was found that the catalyst could be recovered and reused without significant loss of its activity. The use of this method provides a novel and improved modification of Knorr synthesis in terms of clean reaction profile, use of a safe catalyst and solvent‐free conditions.     

Efficient Method for Iodination of Alcohols using KI/Silica Sulfuric Acid (SSA)

A straightforward and effective procedure for the conversion of benzylic and allylic alcohols to the corresponding iodides using KI/SSA in acetonitrile at room temperature.     

硅胶硫酸催化肟转化为羰基化合物的有效方法

在硅胶硫酸催化和十二烷基磺酸钠存在下,肟与多聚甲醛在90℃的水溶液中搅拌反应15～120 min生成相应的羰基化合物,收率68%～98%.     

浓硫酸与锌反应产生氢气的验证及原因探究

通过使用品红溶液、硫酸铜溶液及泡泡水等,可以验证浓硫酸与锌粒在加热条件下有氢气生成。提出产生氢气的原因与浓硫酸的自偶电离有关,并用多种金属进行验证。     

硫酸交联壳聚糖膜质子传导行为的研究

制备了硫酸交联壳聚糖膜, 通过研究其质子传导性能、力学性能、化学成分及结构变化, 分析了硫酸与壳聚糖分子间的交联方式, 并对质子传导机理进行了解析. 结果表明, 硫酸交联可显著改善壳聚糖膜的质子传导能力与力学性能, 这种改善作用在交联6 h后趋于稳定, 交联6 h后的壳聚糖湿膜在室温下时质子传导率为0.0472 S• cm^－1, 比未交联的壳聚糖膜提高5倍左右. 硫酸交联壳聚糖膜中的质子传导率与温度的关系符合Arrhenius定律, 质子传导激活能为18 kJ/mol, 其传导机制应属于Grotthus机制. 硫酸对提高壳聚糖膜的质子传导能力主要有两方面的作用: (1) H₂SO₄可使壳聚糖分子中NH₂质子化形成NH₃^＋. (2) 处于两个氨基之间的SO₄^2－在质子传递过程中起离子桥梁作用, 参与以水分子为载体的质子传导过程, 从而减小质子传导的阻力, 提高了质子传导率.     

亚硝酰硫酸的离子色谱分析方法研究

建立了离子色谱法(IC)测定亚硝酰硫酸含量的分析方法。考察了亚硝酰硫酸选择性水解生成硝酸和硫酸的条件。亚硝酰硫酸的最佳色谱分析条件为:电导检测器,pH3.5的磷酸二氢钾缓冲溶液作流动相,流速1 mL.min-1,柱温45℃。在优化实验条件下,NO2-、NO3-和SO42-的线性范围分别为2.375~9.515、0.375~1.548、2.051~8.263 mmol.L-1,相关系数均大于0.999 9。样品中NO2-、NO3-和SO24-的加标回收率为99%~101%,其相对标准偏差(RSD)均小于1.0%。通过对各离子含量的测定,用氮平衡法计算出亚硝酰硫酸的含量,相对标准偏差均在0.1%以内。建立的方法与传统的氧化还原滴定法分析亚硝酰硫酸相比,具有分析结果准确、简便快速、成本低的特点,已用于工厂中该产品的质量控制。