硫酸根离子对草酸-硫酸混合酸中制备的多孔阳极氧化铝光致发光特性的影响

采用电化学阳极氧化法,分别在草酸、硫酸及两者不同浓度比的混合酸中制备了AAO薄膜样品,并分别观察了在250,296 nm光激发下的光致发光(PL)特性。结果表明:草酸和混合酸中制备的AAO薄膜,在250~550 nm范围内的光致发光与不同存在或分布形式的草酸杂质形成的发光中心相关。硫酸根离子对混合酸中制备的AAO薄膜的PL特性有很大影响,随硫酸根离子浓度的增加发光峰位逐渐蓝移。分析了出现上述实验现象的原因。     

Ultrasound accelerated esterification of palmitic acid with vitamin C

The esterification of palmitic acid with vitamin C in the presence of concentrated sulfuric acid as the solvent and catalyst by means of 25 kHz ultrasonic irradiation to obtain l-ascorbyl 6-palmitate is studied. By using ultrasound the dissolution rate of the reactants can be accelerated greatly, the reaction time of esterification can be reduced from 36 to 2h, and better yield (90-93%) of ester can be given by using 95% concentrated sulfuric acid as the solvent and catalyst, contrast to the yield of 75-85% by using 99% concentrated sulfuric acid without ultrasound. The influence of reaction conditions and ultrasonic parameters to the yield of ascorbyl palmitate are reported.     

乙酰水杨酸的制备

以水杨酸和乙酸酐为原料,以浓硫酸为催化剂,合成乙酰水杨酸。考察了对反应产率的影响因素,实际结果表明:水杨酸和乙酸酐物质的量比为1∶2,反应温度为80℃,反应时间为30min时,反应产率为86.65%。     

Ultrasonic versus silent methylation of vegetable oils

The profile of fatty acid methyl esters (FAME) of different vegetable oils produced under ultrasonic irradiation and conventional heating were compared. In the presence of potassium hydroxide as catalyst, the distribution of FAME was quite similar for both procedures, while in the case of sodium hydroxide ultrasonic irradiation gave better results. The FAME profile resulted from the reaction catalyzed by sulfuric acid was almost the same with the one resulted from the reaction catalyzed by KOH, while boron trifluoride can give rise to many artifacts, thus is not a reliable catalyst.     

分光光度法测定阿奇霉素的改进

通过对阿奇霉素显色反应过程中硫酸浓度,反应时间,反应温度的研究,优化了分光光度法测定阿奇霉素含量的方法。结果表明,阿奇霉素在11.26—45.03mg.L-1浓度范围内,显色溶液在482nm处吸光度与其浓度具有良好的线性关系,线性回归方程为A=0.0172C（mg.L-1）＋0.0504,平均回收率为99.1%（n=9）。该方法简单,比传统光度法更灵敏、准确,适合于阿奇霉素含量的快速测定。     

Synthesis of mono- and bis-spirooxindole derivatives “on water” using double salt of aluminum sulfate–sulfuric acid as a reusable catalyst

Molecular Diversity - The preparation of double salt of aluminum sulfate–sulfuric acid (Al4(SO4)6·(H2SO4)·24H2O) by the reaction of aluminum sulfate and sulfuric acid in water is...     

藏红T褪色光度法测定四溴双酚A的含量

在硫酸介质中,四溴双酚A （TBBP-A）对Fenton反应产生的羟基自由基氧化藏红T的反应具有抑制作用,据此建立了分光光度法测定痕量四溴双酚A的新方法.探讨不同酸介质种类、硫酸溶液用量、FeSO4溶液用量、藏红T用量、过氧化氢用量、加热时间和加热温度等因素对反应体系的影响.在较佳实验条件下,方法的线性回归方程为：△A=-0.0005＋ 2668.1C,相关系数r=0.9929,线性范围为5.0×10-6-3.2×10-4mg/mL,检出限为2.8×10-6mg/mL.将方法应用于实际样品的测定,加标实验回收率在86.7％-107％之间,相对标准偏差（RSD）为4.3％一5.1％.该方法具有操作简便、快速特点,测定结果令人满意.     

Synthesis of multi-functionalized benzofurans through the condensation of ninhydrin and phenols using SSA as a recyclable heterogeneous acid catalyst

A simple and efficient one-pot methodology has been developed for the synthesis of biologically important multi-functionalized 3-(2\(^{\prime }\)-hydroxyaryl)-2-(2\(^{\prime }\)-carboxyphenyl)benzofurans using silica sulfuric acid (SSA) as a heterogeneous acid catalyst in DMF medium. The significant advantages of this methodology are the use of SSA as a recyclable solid acid catalyst, operational simplicity, easy availability of the starting materials, and good yield of the products with high atom-economy.     

Ultrasonic-assisted ozone degradation of organic pollutants in industrial sulfuric acid

In this work, a combination of ozone (O₃) and ultrasound (US) has been firstly used to decolorize black concentrated sulfuric acid with high organic content. The effect of different reaction factors on the transparency, extent of decolorization, H₂SO₄ mass fraction, and organic pollutants removal is studied. In addition, the systematic interaction between ultrasound and ozone on the decolorization process is reviewed through comparative experiments of O₃, US and US/O₃. A sulfuric acid product that meets the requirements for first-class products in national standards, with an extent of decolorization of 74.07%, transparency of 70 mm, and a mass fraction of 98.04%, is obtained under the optimized conditions. Under the same conditions, it has been established that the treatment time can be saved by 25% using the US/O₃ process compared to using O₃. Further, the production of oxidative free radicals (•OH) in a concentrated sulfuric acid system is enhanced using the US/O₃ process compared with O₃. In addition, the degree of effectiveness of different oxidizing components on the decolorization process is revealed by adding different free radical shielding agents when the US/O₃ process is used.     

改性ZSM-5分子筛催化合成乙酸戊酯

以ZSM-5为原料,采用浸渍法将其交换成HZSM-5,以HZSM-5为催化剂,对以冰乙酸和正戊醇为原料合成乙酸戊酯的反应条件进行了研究。研究表明,以1.0m ol/L硫酸浸渍后的ZSM-5催化活性最高,当醇酸摩尔比为1.1∶1,催化剂用量为0.4g,反应时间为90m in,反应温度为125—135℃,酯化率可达82.5%。     

催化动力学分光光度法同时测定铜和铁

研究发现 :在硫酸介质中Cu(Ⅱ )和Fe(Ⅲ )能同时催化溴酸钾氧化酸性铬蓝K的褪色反应 ,但二者存在一定的速率差异 ,反应速率常数之比随时间而变化 ,且吸光度的加和性不佳。运用了三层Levenberg Marquardt优化BP神经网络处理实验数据 ,实现了Cu(Ⅱ ) ,Fe(Ⅲ )的催化动力学分析法同时测定。研究了最佳反应和测定条件。用于合成样品和人发中铜和铁的测定 ,结果满意     

Ultrasonics promoted synthesis of thiazolidinones from 2-aminopyridine and 2-picolilamine

The efficient multicomponent synthesis of thiazolidinones from the reaction of arenealdehydes, mercaptoacetic acid and 2-picolilamine or 2-aminopyridine under ultrasound irradiation are reported. The reaction with 2-aminopyridine needs a Lewis acid catalysis to afford the corresponding 2-aryl-3-(pyridin-2-yl)-1,3-thiazolidin-4-ones. All novel compounds were identified and characterized by (1)H and (13)C NMR spectra. Applying the sonochemical methodology, two series of heterocyclic thiazolidinones were synthesized in good yields after short reaction times.     

Fluorimetric Determination of Cerium(IV) with Ascorbic Acid

A simple, sensitive, and selective method for the determination of cerium(IV), based on the oxidative reaction between cerium(IV) and ascorbic acid, has been described. The fluorescence comes from Ce(III) at λ_excitation 298 nm and λ_emission 358 nm, which, in turn, is obtained from the oxidation of ascorbic acid by Ce(IV) in the presence of sulfuric acid. The optimum conditions such as concentrations of ascorbic acid, sulfuric acid media and pH of the buffer solution were investigated. The fluorescent intensity of the system is linear over the range 0.0531 μg/ml to 0.3322 mg/ml Ce(IV) and detection limit and correlation coefficient are 0.0145 μg/ml and R=0.99987,respectively.     

钛膜的电解抛光技术研究

 分析了硫酸、硝酸、氢氟酸;硫酸、乙酸、氢氟酸;乙醇、正丁醇、氯化锌、氯化铝;高氯酸、乙酸;硫酸、甲醇这５种不同电解液组成对钛薄膜表面粗糙度、表面形貌的影响,得出硫酸、甲醇混合溶液是一种较理想的电解液体系。设置合适的抛光电压、温度、时间、泵速等工艺参数,制备出了表面平整光滑,平均粗糙度小于30 nm的钛膜。分析了硫酸、甲醇电解液阳极电压与试样表面减薄速率的关系：试样的减薄速率开始随电压的升高而增大;当电压达到28～34 V时,减薄速率随电压变化很慢,当电压继续增大时,减薄速率又会迅速增大,金属膜继续溶解。     

Comparison between the single-bubble sonoluminescences in sulfuric acid and in water

Single-bubble sonoluminescence (SBSL) is achieved with strong stability in sulfuric acid solutions. Bubble dynamics and the SBSL spectroscopy in the sulfuric acid solutions with different concentrations are studied with phase-locked integral stroboscopic photography method and a spectrograph, respectively. The experimental results are compared with those in water. The SBSL in sulfuric acid is brighter than that in water. One of the most important reasons for that is the larger viscosity of sulfuric acid, which results in the larger ambient radius and thus the more contents of luminous material inside the bubble. However, sonoluminescence bubble’s collapse in sulfuric acid is less violent than that in water, and the corresponding blackbody radiation temperature of the SBSL in sulfuric acid is lower than that in water. Supported by the National Natural Science Foundation of China (Grant Nos. 10434070 and 10704037) and the Ministry of Education Priorities Project of China (Grant No. 103078)     

Synergistic effect between 4-(2-pyridylazo) resorcin and chloride ion on the corrosion of cold rolled steel in 0.5 M sulfuric acid

The corrosion inhibition of 1-(2-pyridylazo)-2-naphthol (PAR) on the corrosion of cold rolled steel in 0.5 M sulfuric acid (H₂SO₄) was studied using weight loss method and potentiodynamic polarization method. Results obtained revealed that together with chloride ion, PAR is an effective corrosion inhibitor for steel corrosion in sulfuric acid. It was found that for steel corrosion inhibition in the presence of single PAR in sulfuric acid the Temkin adsorption isotherm may be used to explain the adsorption phenomenon. For the mixture of PAR and NaCl used as corrosion inhibitor, however, the Langmuir adsorption isotherm can be used to satisfactorily elucidate the adsorption of mixture of PAR and NaCl. Potentiodynamic polarization studies showed that single PAR mainly acts as a cathodic inhibitor for the corrosion of steel in 0.5 M sulfuric acid. The mixture of PAR and chloride ion, however, acts as a mixed type inhibitor that mainly inhibits cathodic reaction of the steel corrosion in sulfuric acid. By means of electrochemical polarization tests, a desorption potential at ca. −370 mV was observed for the adsorption of mixture of PAR and chloride ion, when potential reaches this value, adsorbed inhibitor molecule heavily departs from the steel surface. For the mixture of PAR and chloride ion, thermodynamic parameters such as adsorption heat, adsorption entropy and adsorption free energy were obtained from experimental data of the temperature studies of the inhibition process at four temperatures ranging from 30 to 45 °C, the kinetic data such as apparent activation energies and pre-exponential factors at different concentrations of the inhibitor were calculated, and the effect of the apparent activation energies and pre-exponential factors on the corrosion rates of cold rolled steel was discussed. The most suitable range of inhibitor concentration was discussed. The inhibitive action was satisfactorily explained by using both thermodynamic and kinetic models. Synergism between chloride ion and PAR was proposed. The results obtained from weight loss and potentiodynamic polarization were in good agreement.     

Continuous acid-catalyzed esterification using a 3D printed rotor–stator hydrodynamic cavitation reactor reduces free fatty acid content in mixed crude palm oil

Free fatty acid (FFA) content in FFA-rich mixed crude palm oil (MCPO) was reduced through a continuous esterification process. The reaction conditions were optimized, the yield purified esterified oil was determined, and the average total electricity consumption of the entire process was evaluated. The key component of this study was the cost-effective, 3D-printed rotor that was installed in a continuous rotor–stator hydrodynamic reactor. The surface of the rotor was designed with spherical holes where the center-to-center distance between them was fixed. Response surface methodology (RSM) using central composite design (CCD) was employed to analyze the design of experiments (DOE) and optimize FFA-content reduction. The optimized conditions were 17.7 vol% methanol, 2.9 vol% sulfuric acid, a 3000 rpm rotor speed, and surface holes measuring 4 mm in diameter and 6 mm in depth. The experimental results showed that the FFA content in MCPO was reduced from 11.456 to 1.028 wt% upon esterification under these optimal conditions. The maximum yield of esterified oil from the phase separation step was 96.07 vol%, and that of the purified esterified oil was 91.27 vol%. The average total energy consumed by this hydrodynamic cavitation reactor to produce this esterified oil was 0.0264 kW h/L. This 3D printed rotor–stator reactor is a promising, novel reactor technology for producing biodiesel from FFA-rich oils.     

流动注射化学发光法测定芦丁

在酸性介质中,硫酸高铈氧化芦丁能产生弱发光,而罗丹明6G(Rh6G)能大大增强此弱发光,由此建立了流动注射化学发光法测定芦丁的新方法。研究了影响化学发光强度的各种因素,优化了硫酸、硫酸高铈和Rh6G等条件,对样品中可能存在的各种干扰物质进行了研究,并初步探讨了化学发光反应可能的机理。该方法的线性范围为1.0×10-7～1.0×10-4 mol·L-1,方法的检出限为8.1×10-8 mol·L-1,对1.0×10-5 mol·L-1的芦丁进行11次平行测定,其相对标准偏差为1.5%,回收率为99.0%～104.0%。该方法应用于芦丁片剂中芦丁含量的测定,取得了满意的结果。     

测定诺氟沙星的流动注射化学发光新方法

在硫酸介质中,高锰酸钾可氧化硫代硫酸钠产生化学发光,诺氟沙星对该化学发光反应具有增敏作用。据此建立了流动注射化学发光测定诺氟沙星的新方法。在最佳条件下,诺氟沙星的线性范围为2.00×10^-8—2.00×10^-6g·mL^-1,检出限（3σ）为8.36×10^-9g·mL^-1。对3.00×10^-7g·mL^-1的NFLX标准溶液平行测定9次,相对标准偏差为2.7%。应用于诺氟沙星胶囊的测定,回收率分别为102.9%,103.9%。结合荧光光谱和紫外光谱,对该体系机理进行探讨。     

超声场对钛基PbO2电极电化学氧化Cr3+过程电流效率的影响

本文研究了超声场对Ti／SnO2 Sb2O3／PbO2电极电化学氧化Cr3 过程的影响,探讨了在不同的操作电流密度、反应温度、硫酸浓度及Cr3 浓度下,超声场对硫酸介质中Cr3 电化学氧化生成Cr2O72-过程中的电流效率的影响,并用扫描电镜对有无超声场时不同反应时间下的电极形貌进行了分析。实验结果表明:在相同的反应条件下,有超声场作用时Cr3 电化学氧化过程的电流效率明显高于无超声场时的电流效率。扫描电镜测定发现,有超声场作用时不同反应时间下电极的形貌有明显的变化。