Comments on the iodide/iodate method for characterising micromixing

Qualitatively the iodide/iodate method, in which the iodine yield is measured, has provided reliable results for assessing the extent of micromixing of miscible reagents. Quantitative treatment requires however a robust kinetic model. Comparison of published models shows large differences due to the complexity of the iodine-forming reaction. The kinetics needs to be re-determined employing modern techniques for fast reactions and under the conditions (concentrations, ionic strength, etc.) used in mixing studies.     

Oxidation of iodide to iodate concurrently with evolution of oxygen at Kelgraf composite electrodes

The oxidation of I^– to IO ₃ ^– in acidic media occurs at numerous electrode materials at potential values corresponding to the anodic discharge of H₂O with simultaneous evolution of oxygen. In the study reported here the anodic current density for IO ₃ ^– production was measured by difference voltammetry at rotated disc electrodes (r.d.e.'s) constucted from pure glassy carbon (GC) and Kelgraf (graphite plus Kel-F) composite materials. These signal values (S) were normalized relative to the background current (B) for oxygen evolution measured at 1.75 V vs SCE, a potential corresponding to the transport-limited production of IO ₃ ^– at GC. Despite a small positive shift in E _1/2 with decreasing fractional active area, the signal-to-background ratio (S/B) at the Kelgraf electrodes was enhanced relative to that for the GC electrode. For example, SIB at a 2% Kelgraf r.d.e. was nine times larger than at a GC r.d.e. This corresponds to an increase in current efficiency (S/(S + B)) for IO ₃ ^– production from about 50% at the GC r.d.e. to about 90% at 2% Kelgraf r.d.e. This is explained on the basis of (i) a significant decrease in total background current as a result of the decreased fraction of the Kelgraf surface that corresponds to carbon, and (ii) a larger flux density of I^– at the carbon microelectrodes in the Kelgraf r.d.e., as compared to the GC r.d.e., as a result of radial diffusion, i.e. the so-called edge effect.     

关于亚硫酸氢纳还原碘酸钾遇淀粉变蓝实验原理的讨论

本文通过设计亚硫酸氢纳还原碘酸钾遇淀粉变蓝实验对该反应的反应动力学方程、淀粉溶液的变蓝原理、反应机理进行全面深入的讨论。     

The reaction of picric acid with epoxides I. A colorimetric method

A colorimetric method has been developed for the analysis of epoxides by reaction with picric acid. Picric acid was found to be the best of several acidic chromophores in its reaction with epoxides. Despite a nonquantitative reaction, the product concentration is proportional to the original concentration, i.e., it follows Beer’s Law. The reaction variables were studied with methyl mono- and diepoxystearates, epoxidized cottonseed oil andVernonia anthelmintica oil. The general applicability of the method was demonstrated by reaction with butyl epoxystearate, styrene oxide, a number of 3-substituted propylene oxides and two commercial epoxy resins. Presented in part at the First World Fat Congress, Hamburg, Germany, in October, 1964, and at the AOCS Meeting in Houston, Texas, April 1965.     

三水碘化锂的制备方法初步探究

在充分了解国内外三水碘化锂制备方法的前提下,以贵州某公司碘回收工艺过程产生的含碘吸收液为原料,对三水碘化锂的制备方法进行了初步探讨,主要包括产品制备方式、反应原料液浓度、干燥方式的选择及干燥条件的确定等,为三水碘化锂制备工艺路线的确定提供可靠的前期保障。     

Preparation of coatings on powders by the iodide transport method

The capabilities of the iodide transport method for the deposition of coatings on powders have been investigated. It has been demonstrated that this process is affected by different factors, such as the temperature, time, structure of the substrate material, and its dispersity.     

The reaction of divinyl sulfone withalpha-eleostearic acid

Summary The reaction of divinyl sulfone withalpha-eleostearic acid has been studied. The reaction product was found to be monomeric, consisting of only one divinyl sulfone and one eleostearic moiety. Contrary to expectations, the adduct contained only two ethylenic linkages rather than three and the addition product is considered to be a transannular sulfone. One of the laboratories of the Southern Utilization Research and Development Division, Agricultural Research Service, U. S. Department of Agriculture.     

醋酸乙烯反应装置参数灵敏性研究

在化工工业中,探索化工装置的安全生产条件具有重大的实际意义。采用参数灵敏性的方法研究放热反应的热失控问题得到了广泛的关注。对于强放热的反应,要确保温度在安全范围内,以防装置中温度过高或者压力过大发生危险。本文以醋酸和乙炔反应的装置为例,利用已知的条件建立模型研究反应的灵敏度和热失控问题。分析了输入条件(进料温度、传热、气体流速、进料摩尔比、初始压力)对反应物转化率、温度灵敏度及反应器内温度分布的影响。研究结果表明,在乙炔和醋酸反应装置中进料温度、传热及总压是影响转化率和温度的主要因素并得出了相应输入参数的临界值。     

The reaction of mercaptoacetic acid with methyl linoleate and linoleic acid

The reaction of mercaptoacetic acid with methyl linoleate and with linoleic acid was investigated. The reaction proceeded at low and erratic rates, with and without catalysts, such as peroxides at various temperatures, but could be accelerated by use of a large excess of mercaptoacetic acid. Addition of 1 mole of mercaptoacetic acid to 1 mole of methyl linoleate resulted in a product containing about 40% of mono-adduct. Ozonolysis of the purified mono-adduct yielded approximately equimolar quantities of caproic and azelaic acids, indicating that addition occurred about equally at the 9,10- and 12,13-ethylenic bonds. The dicarboxylic acid and the dimethyl ester of the mono-adduct and the tricarboxylic acid and trimethyl ester of the di-adduct of linoleic acid and mercaptoacetic acid were prepared, and the infrared spectra and some physical and chemical characteristics of these products were determined. The infrared spectra of the reaction products were obtained and correlated with functional groups which give rise to them. Bands at about 7.8 and 8.8 μ, commonly observed in long chain acids and esters and ascribed to C−O vibrations, are intensified in the sulfur-containing reaction products, suggesting characteristic absorption of C−S compounds at almost identical wavelengths. The formation of adducts was accompanied by a high degree of isomerization of the unreacted ethylenic bonds from thecis to thetrans form both in the mono-adduct and in unreacted methyl linoleate. The methyl linoleate recovered contained about 12% diene conjugation, but catalytic quantities of mercaptoacetic acid were not effective in inducing conjugation.     

催化反应液中氨基葡萄糖酸的光度法测定

利用氨基葡萄糖酸在强酸性(pH 1.5)条件下形成内酯,并与羟胺碱-三氯化铁显色体系生成红棕色络合物,建立了氨基葡萄糖酸的分光光度检测方法,给出了线性方程。检测波长为500 nm,在1.0×10-5～9.0×10-5 mol/mL范围内呈现良好的线性关系,平均加标回收率为99.28%,相对标准偏差≤4.91%。该方法操作简单、结果稳定、选择性和灵敏度良好,能成功应用于实际样品的检测。     

The liquid-phase reaction of hexane on acid mordenite

The batch reaction of hexane (H) on acid Mordenite at 160°C does not occur by consecutive carbocationic isomerization (H→2MP,3MP→2,3DMB→2,2DMB). Instead, a mixture of all the isomers in constant ratios was obtained at all conversions between 2% and 13%, as expected for quenching or desorption of an equilibrium mixture. The ratios of the monobranched isomers to the dibranched isomers did not correspond, however, to their equilibrium at the reaction temperature, or to the equilibrium of the corresponding carbocations. The existence of mechanistic differences between the reaction under these conditions and the experiments conducted either with nonoxidizing superacids in solution (the source of the accepted mechanistic model) or with a Pt-containing catalyst in the presence of hydrogen, in the gas phase, is indicated by these data.     

The reaction of ethylene oxide with oleic acid

The base-catalyzed reaction of ethylene oxide with oleic acid can be divided into two stages. The first stage consists of a slow reaction of oleic acid with ethylene oxide to form principally ethylene glycol monooleate; other reactions such as esterification, transesterification and polyglycol formation lag behind. In the second stage, after the addition of approximately one mole of ethylene oxide, the reaction accelerates and transesterification equilibrium is rapidly attained. The composition of products containing several molecules or more of ethylene oxide can be calculated satisfactorily on the assumption of random addition of ethylene oxide and random esterification of the hydroxyl groups. The uncatalyzed reaction is much slower and transesterification equilibrium is attained slowly, if at all. A reaction mechanism based on the difference in basicities of the carboxylate and alkoxide ions (and the relative rates of the competitive ethylene oxide reactions) is presented for the base-cat-alyzed reaction.     

The reaction of kaolin clay with orthophosphoric acid

Conclusions Orthophosphoric acid reacts with kaolinite clay already at room temperature. The reaction results in the dissociation of some kaolinite and the formation of acid aluminophosphates, its rate is at maximum during the first 4–10 days of the storage of the composition of clay with the acid, and it ceases when the composition is stored for longer periods.The triderivative of aluminophosphate begins to form only on heating above 100°C. At a temperature of 400°C and higher it forms more rapidly while the proportion of mono- and diderivatives of aluminophosphates diminishes.The fact that in compositions of kaolinite clay with orthophosphoric acid in storage only water-soluble acid aluminophosphates are formed and triderivative of aluminophosphate is absent makes it possible to produce clay-containing aluminosilicate compositions containing orthophosphoric acid at refractory plants in ready-for-use form.Translated from Ogneupory, No. 7, pp. 43–48, July, 1977.     

The preparation of C19 dicarboxylic acid by the koch reaction

This paper describes the preparation of C₁₉ dicarboxylic acid by the Koch reaction with carbon monoxide and sulfuric acid of oleic, tall oil fatty, and partially hydrogenated tall oil fatty acids. The effects of changing reaction conditions upon the yield and purity of the product were examined. With the best conditions, it was possible to prepare light-colored, heat-stable C₁₉ dicarboxylic acid in 83% overall weight yield at 96% purity, containing 75% tertiary isomers and 25% secondary.     

The oxidation of 9:10 diketostearic acid by peracetic acid (baeyer and villiger reaction)

Diketostearic acid 9:10 is readily and speedily oxidized by peracetic acid, at low temperatures to high yields of azaleic acid and nonanoic acids.     

固体酸催化反应精馏法合成酯的研究

本文对固体酸催化剂反应精馏法合成乙酸乙酯的反应进行了研究,分别考察了不同的回流比、酸醇摩尔比对反应精馏过程的影响,确定反应的较佳工艺条件,并结合工艺条件进行催化剂的筛选。     

构型转换法制备赤式紫胶桐酸及反应机理分析

以苏式紫胶桐酸为原料,通过构型转换法制备赤式紫胶桐酸.采用FTIR、质谱、核磁(1HNMR/13CNMR)、TG、DSC、XRD、手性拆分、比旋光度等表征手段对所得产物进行了分析确证.对紫胶桐酸苏式到赤式构型的转换机理进行了初步探究.结果表明:FTIR、质谱、核磁显示,产物与苏式紫胶桐酸结构一致;XRD、DSC、TG结...