硫酸渣中全铁含量的测定

硫酸渣是一种铁含量高的硫酸副产品,广泛应用于钢铁及水泥行业。全铁含量是供需双方主要的结算指标,但目前尚无相应的检测标准,大都采用《硫铁矿和硫精矿中全铁含量的测定》。该方法能耗高(11～14 kW.h),检测时间长(3～4 h)。因此,经过摸索,利用盐酸溶样,重铬酸钾氧化还原滴定二价铁离子,取得了较好的效果。     

Determination of total sulfur in canola oil

A rapid and sensitive chromatographic method for the determination of total sulfur in canola oil is described. All forms of sulfur in the oil are quantitatively converted to sulfate in an oxygen bomb. The sulfate is separated from other ions and measured using an ion chromatograph equipped with a conductivity detector. Standards containing different forms of sulfur were prepared and analyzed with this method. Recovery achieved on 11 compounds covering the concentration range from 9.3 to 143.5 mg/kg S ranged from 95.7% to 102.2%. The coefficient of variability of total sulfur in canola oils ranged from 1.0% to 2.9%. Values obtained on high sulfur content mustard oils when plotted vs the values determined by barium precipitation method showed a correlation coefficient of 0.997 and provided a slope of 1.0. This new method employing comparatively simple equipment requires less than 40 minutes for a complete analysis and is reliable for the determination of as little as 0.5 mg/kg S in canola oil.     

A thiourea-UV assay for total glucosinolate content in rapeseed meals

A rapid and sensitive method for the determination of the total glucosinolate content in rapeseed is described. The method is based on the specific UV absorbance of the thioureas and oxazolidine-2-thiones. Results obtained were confirmed by gas-liquid chromatography. Recoveries varying from 94 to 103% were obtained for samples containing mixtures of isothiocyanate and oxazolidine-2-thione (a total of 0.25 to 0.78 mg per assay). The relative stadard deviation for rapeseed meals varied from 4 to 10% for the total glucosinolate content (expressed as 3-butenylisothiocyanate) and depended on the size of sample taken. The relative standard deviation for oxazolidine-2-thione varied from 5 to 35% for the same meal. The lower limit of detection for rapeseed meal is of the order of 0.25 mg of 3-butenylisothiocyanate per g. NRCC No. 15090.     

降低湿法磷酸中硫酸含量的工艺技术

采用在湿法磷酸中加入磷矿浆来降低磷酸的硫酸含量。介绍采用磷矿浆脱除硫酸根的反应原理,工艺路线的选择,矿浆添加量的计算及实施效果。通过计算,脱硫后反应、过滤装置生产能力提高,30万t/a磷酸装置每年节省硫酸8 700 t,减少消耗支出300多万元。     

吡唑啉酮分光光度法测定废硫酸中的微量三氯乙醛

研究了吡唑啉酮分光光度法测定水中三氯乙醛的原理,并将其应用到三氯乙醛副产废硫酸中微量三氯乙醛(酸)的测定中.确定了吡唑啉酮分光光度法为南通江山农药化工股份有限公司三氯乙醛废硫酸中微量三氯乙醛(酸)定量分析的最终分析方法.     

高镁磷尾矿在硫酸中的溶解动力学

对高镁磷尾矿在硫酸中的溶解动力学进行了研究.考查了硫酸质量分数及反应温度对酸解过程的影响;选用考虑了自阻化因素的德罗兹多夫方程1/tln100/100-α-βα%/t=k描述酸解过程的动力学.研究结果表明:反应速率常数随温度的升高而增加,随硫酸质量分数的增加而减小.该反应属于扩散控制,反应活化能约为4～7kJ/mol.     

硫酸脲分解磷矿影响因素研究

本文对硫酸脲分解磷矿粉反应的影响因素(反应温度、尿素与硫酸的摩尔比)进行了分析。并对结晶的形状进行观察和讨论。实验结果表明:升高反应温度,反应速率提高,在相同反应时间下,转化率提高,但同时结晶变小;随着尿素与硫酸摩尔比的增大,反应速率有所降低;添加尿素能够生成尿素和硫酸钙的加合物,因此结晶较大,减弱"包裹"或"钝化"现象,有利于第二阶段反应进行。在工业实施时,应综合考虑各种因素的影响及各因素间可能的制约和协同作用。     

硫酸分解磷矿第一阶段反应动力学研究

对硫酸分解磷矿粉的第一阶段反应进行了动力学研究,通过对实验数据的分析,证明此阶段反应为一级反应。反应速率常数与温度的关系符合阿累尼乌斯方程,活化能Ea为8．65kJ／mol。     

苯酚-硫酸法测定灵丹多糖胶囊中多糖的含量

目的:制定灵丹多糖胶囊中多糖的含量测定方法。方法:采用苯酚-硫酸显色法在490 nm波长处测定灵丹多糖胶囊中多糖的含量。结果:以葡萄糖作为对照品其浓度在0.12~0.20 mg/m L之间与吸光度有良好的线性关系,A=3.9635 C+0.0013,r=0.9999,精密度考察RSD为0.10%,稳定性考察RSD为0.12%,稳定性考察RSD为0.12%,平均加样回收率为99.95%,RSD为0.23%,三批样品多糖平均含量为5.22%。结论:苯酚-硫酸显色法操作简便、准确,可作为该胶囊制剂中多糖含量的控制方法。     

Rapid Determination of Nitroguanidine and nitrate ion in the spent sulfuric acid

A rapid method for simultaneous determinations of nitroguanidine and nitrate ion in the spent sulfuric acid has been developed. This method consists of merely diluting an aliquot of sample with water and measuring the absorbances of nitroguanidine and nitrate ion at 265 nm and 203 nm, respectively. In the concentration ranges studied, average accuracies of better than 1% and 2% were obtained for nitroguanidine and nitrate ion, respectively. The precision was better than 1% in both cases.     

Kinetics of the reaction between urea and formaldehyde in the presence of sulfuric acid

The kinetics of the reaction between urea and formaldehyde were studied in the presence of various amounts of sulfuric acid (5–45% by weight) at different temperatures (5°, 15°, and 25°C). The reaction was shown to follow first-order kinetics. The activation energy for the reaction varies from 12.51 kcal/mole to 14.59 kcal/mole in the range of sulfuric acid concentration studied.     

Absorption and reaction of isobutene in sulfuric acid—II: Determination of parameters and optimal conditions in bubble columns

The sulfuric acid catalysed absorption and reaction of isobutene was studied in a bubble column (10.2 cm diameter, 256 cm height) covering a wide range of liquid phase compositions. At acid concentrations of 40–48% wt and tert-butanol concentrations of 3.2–4.3 moles/l. the absorption rate has a maximum value. From measurements in the slow reaction or diffusional regime of mass transfer it was possible to obtain a value of liquid side mass transfer coefficient k_L. As interfacial areas and solubilities of isobutene were determined by independent means the rate constants of the hydration could be evaluated from this and other studies in bubble column reactors. The reaction rate constant follows a simple correlation which considers the effect of the acid and the generated butanol. Thus, all relevant data of the absorption-reaction system are available. The significance of these data was checked by a dynamic study in a smaller bubble column.     

硫铁矿制酸装置生产优质液体SO_3联产发烟硫酸及精制硫酸

阐述用硫铁矿制酸装置生产液体SO_3联产w(H_2SO_4)115%的发烟硫酸及精制硫酸的产品方案设计、生产工艺过程以及在生产过程中遇到的问题及其解决办法。在硫铁矿制酸装置上成功生产3种产品,使产品售价平均达800元/t以上,大大提高了硫酸企业的市场竞争力。     

高效液相色谱法测定化妆品中熊果酸的含量

采用甲醇超声提取,液相色谱分离的方法测定化妆品中熊果酸的含量。色谱条件为:Agilent HC-C18(250 mm×4.6 mm,5μm)色谱柱,流动相V(甲醇)∶V(水)∶V(冰乙酸)=87∶13∶0.03,流速1.0 mL/min,紫外检测波长215 nm。结果表明,在此条件下熊果酸在0.2μg/mL~103μg/mL与相应的峰面积具有良好的线性关系(r>0.999 7),线性回归方程为y=25.367 5x 0.546 9,回收率在96.4%~101.3%,方法精密度RSD<3.6%。     

分光光度法测定氢溴酸中的游离溴

研究了用分光光度法测定氢溴酸中的游离溴含量,并对测试条件进行了优化。结果表明,方法的回收率在97%~102%,标准偏差为0.33×10-6,满足测试要求,可以用于PTA生产实际。     

Determination of total nitrogen content by different approaches in petroleum matrices

Two analytical methods are developed and validated for determination of low total nitrogen levels (below 0.0150%) in different petroleum matrices. The experimental and the instrumental conditions are optimized during the study. The oxidative combustion method with chemiluminescence’s detection is automatic with less handling while the Kjeldahl method involves more manual handling procedures and hence, has more potential for problems rise from contamination. The oxidative combustion with chemiluminescence’s detection method is more sensitive, faster (i.e. the determination requires few minutes compared to several hours with Kjeldahl method) and lees hazardous (i.e. no handling of dangerous boiling sulfuric acid). The estimated analytical characteristics suggest that two methods are reliable: the mean values of recovery for the Kjeldahl method and the other method are respectively 91.5% and 98.6%. The relative uncertainties are less than 2.5% and 2.8% respectively for the developed methods. The detection limits, based on the triple standard deviation, are 5 and 0.03 mgN kg⁻¹ respectively.     

紫外分光光度法测定蛇足石杉中总生物碱含量

以石杉碱甲为对照品,采用紫外分光光度法在313 nm处测定蛇足石杉中总生物碱含量。结果表明,测定在4.36-21.80μg/mL范围内线性关系良好,回归方程:A=0.026 17C-0.023 14,R=0.999 18(n=7),平均加标回收率为103.2%,相对标准偏差(RSD)为2.13%。实验结果表明,用紫外分光光度法测定蛇足石杉中总生物碱含量具有稳定性好、方法简便的优点。     

乙炔硫酸清净中硫酸单耗的影响因素

分析了100万t/a聚氯乙烯装置乙炔硫酸清净中硫酸单耗的影响因素,提出了解决措施,达到了节能降耗的目的。     

The rate of the hydrogen discharge reaction on platinum in sulfuric acid solution

The i_o for the H⁺/H exchange on Pt was found to be dependent on H₂SO₄ concentration, giving a linear log—log relation with a slope of 0·5. For any given H₂SO₄ concentration, i_o was virtually independent of potential to an anodic value at which the Pt-associated H concentration dropped to a low value. Comparisons are made with literature results. The influence of the dilute double layer on i_o appeared to be minimal over a wide range of H₂SO₄ concentrations.     

长柱金丝桃总黄酮含量的测定

长柱金丝桃又名红旱莲、湖南连翘,为藤黄科金丝桃属植物黄海棠的全草。长柱金丝桃含有二蒽酮类衍生物、黄酮类等化学成分。本文阐述了长柱金丝桃总黄酮的含量测定。