Decarbonylation Kinetics of Formic Acid in Aqueous Sulphuric Acid Solutions

Decarbonylation of formic acid in 46.6–80.2% (6.5–14.1 m) sulphuric acid was studied by driving CO out of the reaction medium by an air current followed by its photometrical determination with Ag-Na-sulphamoyl-benzoate. The logarithm of the reaction rate constant increases straight with the acidity of the medium in the 6.5–12.6 M H₂SO₄ range. The data obtained argue in favour of a possible implication of a sulphuric acid molecule respectively hydrogensulphate ion in a rate controlling step.     

Selectivity in Fast Reactions of Aqueous Oh-Radicals with Amides

Measurement of rates of abstraction of H atoms by aqueous OH radicals from specific sites in aliphatic amides by the technique of pulse radiolysis-kinetic spectroscopy establishes that in this reaction, in which gross rates of reaction fall short of the diffusion-controlled limit by no more than a factor of 10², there is a systematic variation of reactivity with structure. This variation parallels dependence of reactivity upon structure observed in the reactions of several other free radicals in the gas phase.     

Antimony Solubility and Speciation in Aqueous Sulphuric Acid Solutions at 298 K

This work is an experimental and theoretical study of antimony speciation and the solubility of Sb₂O₅, Sb₂O₃ and Sb₂(SO₄)₃ at 298 K in aqueous sulphuric acid solutions (0 to 6 kmol/m³). A thermodynamic model was developed to quantify the solubility products and aqueous metal speciation. Main dissolved species were H₃SbO_3(aq) and H₃SbO_4(aq). The solubility of antimony increases with increasing solution acidity and with the presence of hydrogen peroxide in the solution. The following standard equilibrium constants at 298 K were obtained: Log K⁰_(Sb2O5) = 11.7±0.5, Log K⁰_(Sb2O3) = 32±1, and Log K⁰_(Sb2(SO4)3) = 55±2.     

Phase Transfer Catalyzed Bromide—Chloride Exchange: Dependence of Equilibrium Position and Selectivity Constant on Nature and Composition of Aqueous Phase

The position of the equilibrium in the PTC exchange reaction of alkyl chloride with metal bromide salts RCl + MBr ⇌ RBr + MCI under various condtions is utilized for calculation of the selectivity constant K^sel_Cl/Br. This constant is found to be dependent on the nature of the metal cation and the inorganic phase composition. K^sel_Cl/Br can be defined for any point on the phase diagram MCl—MBr—H₂O at a given temperature, solvent and quaternary cation.     

孟山都公司硫酸新技术

介绍孟山都公司开发的硫酸新技术，包括干吸塔、分酸器、Wav-Pak填料、ZeCor耐腐蚀合金、丝网垫、除雾器和热回收系统(HRS)。     

Monitoring the Microscopic Molecular Mechanisms of Proton Transfer in Acid-base Reactions in Aqueous Solutions

This article provides a review of the authors’ collaborative work on acid-base reactions under conditions allowing direct observation of mechanistic details of the proton transfer within reactive complexes of OH groups and the bases RCOO⁻ (R=organic residues) in diffusion-assisted neutralization reactions by using time-resolved UV/Vis emission and IR absorption spectroscopy. We discuss the considerable insight gained by these experiments and outline the current status of the field.     

WSA湿法硫酸装置硫酸酸雾居高不下的原因分析及处理措施

以中煤龙化哈尔滨煤化工有限公司WSA湿法硫酸装置为例,从设备故障、原料气变化、操作不当等3个方面系统分析该装置硫酸酸雾超出设定范围,甚至是硫酸酸雾居高不下的产生原因,并依靠实际操作经验,提出具体的处理措施。     

管式分酸器在硫酸生产中的使用效果

管式分酸器应用于硫铁矿沸腾焙烧制酸装置,效果显著,与原挂钩槽式分酸器相比,干燥塔出口水份含量从０．４ｇ／ｍ＾３降至０．０８ｇ／ｍ＾３。     

废硫酸在双甘膦生产工艺中的应用

[目的]甘氨酸(Gly)法合成草甘膦产生大量的废硫酸,为了提高废硫酸的附加值,将其应用到亚氨基二乙酸(IDA)法草甘膦生产工艺中.[方法]采用废硫酸代替盐酸作为催化剂,以亚氨基二乙酸为主要原料与亚磷酸、甲醛发生反应生成双甘膦.[结果]实验结果表明:使用废硫酸对合成双甘膦反应收率及产品品质均无影响.[结论]对该工艺进行了经济效益分析,结果表明具有良好的经济效益.     

NOx、SO2液相反应研究进展--一种同时脱硫脱氮的新思路

从烟气脱硫脱氮的角度讨论了NOχ与SO2在液相中的一系列反应,包括NO、SO2溶于水与SO3^2-、HSO3^-水溶液间的反应,更为重要的是通过研究SO2^-与HSO3^2-反应制备羟胺二磺酸盐、硫酸羟胺的过程,即生产尼龙66的中间体己内酰胺的必备原料,提出了一种有意义的脱硫脱氮新思路：利用NOχ的氧化性与SO2的还原性在水溶液中构造一自催化自氧化还原反应,并得到有用的工业原料硫酸羟胺。     

Preparation and Characterisation of Proton Exchange Membranes Based on Crosslinked Polybenzimidazole and Phosphoric Acid

Crosslinked polybenzimidazole (PBI) was synthesised via free radical polymerisation between N‐vinylimidazole and vinylbenzyl substituted PBI. The degree of crosslinking increases with increasing content of the crosslinker. The phosphoric acid doping behaviour, mechanical properties, proton conductivity and acid migration stability of crosslinked PBI and linear PBI are discussed. The results show that the acid doping ability decreases with increasing degree of crosslinking of PBI. The introduction of N‐vinylimidazole in PBI is beneficial to its oxidation stability. The mechanical stability of crosslinked PBI/H₃PO₄ membrane is better than that of linear PBI/H₃PO₄ membrane. The proton conductivity of the acid doped membranes can reach ∼10^–4 S cm^–1 for crosslinked PBI/H₃PO₄ composite membranes at 150 °C. The temperature dependence of proton conductivity of the acid doped membranes can be modelled by an Arrhenius relation. The proton conductivity of crosslinked PBI/H₃PO₄ composite membranes is a little lower than that of linear PBI/H₃PO₄ membranes with the same acid content. However, the migration stability of H₃PO₄ in crosslinked PBI/H₃PO₄ membranes is improved compared with that of linear PBI/H₃PO₄ membranes.     

浅谈硫酸生产中的安全

文章简述了使用硫铁矿和硫磺生产硫酸过程中易发生的事故。指出了电除雾装置的爆炸原因和防范措施。并进一步对硫磺和硫酸的储运方法做了归纳及指出了安全注意事项。     

探究微波与有机化学反应的选择性

首先对微波促进的意义进行探讨,重点分析在不同的反应阶段所需要的反应条件。其次重点探讨微波对不同有机化学反应选择性的影响,主要从区域选择性与顺反选择性两方面来进行,帮助读者明确微波与化合物反应选择性的深层意义,在所开展的化合物生产中能够形成更高效的反应模式。     

Ozonation of Sulfur Dioxide in Sulphuric Acid Solution

In this study, the oxidation rates of sulfur dioxide (SO₂) in sulphuric acid solution by ozone and oxygen were compared, and the oxidation mechanism of ozone on SO₂ was investigated. The results showed that the oxidation-reduction potential of the acidic solution was enhanced, the transformation rate of sulfuric acid to sulphuric acid was increased and the absorption driving force was improved in the presence of ozone. By comparing the amount of sulfate ions measured in the experiments and the theoretical amount of sulfate ions calculated from the amount of ozone consumed in the reaction, it can be confirmed that oxygen free radicals from dissociation of ozone are reactive as an efficient oxidant and oxygen from ozone generator participates in the reaction with SO₂. 0.602 mol of effective oxygen was introduced into the reaction by one mole of ozone in 10.15 min at sulphuric acid concentration of 3% (by mass), SO₂ concentration of 1.33% (by volume) and oxygen flow rate of 1.5 L·min^-1 from ozone generator.     

浅析贵州省硫酸生产原料路线

从原料来源条件,工艺技术水平和经济分析等几方面比较了硫酸生产的几种主要原料,供我省硫酸生产企业及有关部门参考。     

硝酸硫酸法生产硝基复合肥

介绍了用硝酸硫酸法生产硝基复合肥的原理、工艺流程、操作控制和消耗定额等,认为该技术工艺简单、生产成本较低,又无固体废弃物处理问题,若以萃取磷酸生产用的多格反应槽代替串联的15个U形管反应器,用硝酸硫酸法生产硝基氮磷钾复合肥技术更易在国内推广。     

Investigations on Selectivity of Gas-Liquid Reactions in Capillaries

Biocatalysis offers a broad spectrum of possible ecological and economic advantages over conventional chemical catalysis processes, e.g., lower energy consumption and high enantio selectivity. The focus of this work is on gas-liquid reactions. These are of great importance in the chemical and biochemical industry and subject of current research since they are often limited by mass transfer or show low selectivity. Different suitable biocatalytically gas-liquid reaction systems were tested in capillary reactor designs in order to obtain information about the interaction between reaction and fluid mechanics. Furthermore, an optical measuring method was established. The experiments were performed in batch mode in a glass beaker with a flow cuvette for UV/Vis measurement of product concentration.     

稀硫酸浓缩的现状与发展

简述了稀硫酸浓缩的意义、原理,对比分析了常见浓缩方法的浓缩范围、优缺点、适用对象。结合实例讨论了几种最新的浓缩新工艺,并预测改进优化现有浓缩装置,利用低温位余热作热源及开发浓缩低浓度酸将会是下阶段稀硫酸浓缩的发展趋势。     

硫酸生产中的废热利用

介绍了硫酸生产中高温、中温、低温位废热利用的状况，节能降耗所取得的经济效益，指出高温位废热利用应进一步加强，中低温位废热利用要大力研究和发展。     

Reactions Between Fulvic Acid,A Soil Humic Compound,and Montmorillonite

The magnitudes of d001 spacings of fulvic acid-Na-montmorillonite complexes were not affected by temperatures between 25 and 60°C. Slightly more than one half of the total amount of fulvic acid adsorbed by Na-montmorillonite was in the interlamellar spaces, with the remainder on external surfaces. The d001 spacings and amounts of fulvic acid adsorbed in the interlamellar spaces of Pb⁺⁺?, Mg⁺⁺?, Co⁺⁺? and Ni⁺⁺? saturated montmorillonite decreased with increase in pH. The capacities of cation saturated clays to adsorb fulvic acid in interlamellar spaces decreased in the following order: Pb⁺⁺ > Mg⁺⁺ > Co⁺⁺ > Ni⁺⁺. The exotherm near 670°C in the DTA curve of the fulvic acid-Na-montmorillonite complex signalized the formation of an interlayer complex.