草酸的生产工艺评述

草酸的合成方法有很多种,工业生产方法主要有碳水化合物氧化法、一氧化碳偶联法、甲酸钠法、乙二醇氧化法、丙烯氧化法等,介绍了上述几种草酸合成工艺,评述了各工艺的优缺点,并对我国草酸工业的发展提出建议。     

氧化法生产草酸的工艺研究

对氧化法生产草酸的工艺条件和工艺过程控制进行了讨论,确定了最佳反应条件。     

草酸的生产工艺及市场分析

介绍了甲酸钠法、碳水化合物氧化法、乙二醇氧化法、丙烯氧化法和一氧化碳偶联法等几种草酸工业生产方法,对其优缺点进行了对比。同时从制药行业、稀土加工业、精细化工行业及其他新兴行业对草酸的下游市场进行了详细分析,为草酸行业未来的发展提供了一些建议。     

氧化法制草酸母液的全部回用

本文探讨了淀粉硝酸氧化法制草酸母液的全部回用问题。试验结果表明,草酸母液的闭路循环利用,不但能提高草酸的收率,而且简化了生产工艺及设备,减轻三废处理,是解决氧化法生产草酸的有效方法。     

氧化法草酸工艺较合成法草酸工艺的优势所在

从原料、工艺路线,设备选型,经济效益及环境保护等几个方面介绍了氧化法草酸和合成法草酸的生产工艺过程,并对两种工艺进行了比较,得出了氧化法草酸工艺的优势所在。     

草酸的生产方法及其进展

草酸作为一种重要的化工原料,广泛用于药物生产、高分子合成、稀土元素提取以及织物漂白等工业,需求量日趋增加。草酸的合成方法有很多种,文章介绍了多糖氧化法、丙烯氧化法、乙二醇氧化法、一氧化碳偶联法、甲酸钠法,评述了各种方法的优缺点。并对我国草酸工业的发展提出了建议。     

木屑法制草酸经济效益可观

<正> 草酸即乙二酸,被广泛用于清除铁锈、防蚀、铝皮膜加工,鞣革加工,染料工业,酚醛树脂溶媒、医药品原料、印染漂白剂、分析试剂,油脂精制,稀土金属精制,其酯可做硝基纤维的溶剂等。对草酸的合成有:碳水化合物硝酸氧化法;甲酸钠脱氢法;丙烯氧化法;乙二醇氧化法;一氧化碳偶联法等。我国于1955年进行工业生产。20多家大厂都是采用以一氧化碳和氢氧化钠作出发的甲酸钠脱氢法。以上这些生产草酸法适用于工业大规模生产,具有受原料、设备厂房制约的不便,而采用木屑法制草酸,它灵活方便,适合于小乡镇企业组织生产,对于开发林副产品,利用科学变废为宝有着深刻意义。以木屑制草酸实际很早就有,但一直因为碱液使用久了而发粘导致不能循环使用,和收率达不到而不能进行工业化生产。我所在国家星火计划的推动下,对其进行了较详细的研究,对碱液套用与收率都进行了突破。     

一氧化碳生产草酸

简述CO生产草酸的甲酸钠法和CO氧化偶连法,着重介绍CO氧化偶联制草酸酯的发展历史和工艺研究的进展情况,并对草酸工业的发展提出建议。     

一氧化碳生产草酸

简述CO生产草酸的甲酸钠法和CO氧化偶连法,着重介绍CO氧化偶联制草酸酯的发展历史和工艺研究的进展情况,并对草酸工业的发展提出建议.     

过氧化氢法制取环氧丙烷

概述国内环氧丙烷市场前景与生产现状。着重介绍国内外研究开发过氧化氢直接氧化法新工艺制取环氧丙烷的重要进展:开发了适用的催化剂,发明了与过氧化氢生产过程耦合的制备环氧丙烷新工艺。     

Quantification of Mixtures of C2 and C3 Hydroxy Acids and Products of Glycerol Oxidation by High-Performance Liquid Chromatography and Quantitative 13C NMR

The aim of this study was to develop an improved general method for detecting and quantifying mixtures of hydroxy acids and other products of glycerol oxidation in aqueous media, to prevent the confusions that can occur due to similarities and interactions between these compounds depending on media conditions. Standard potential products of glycerol oxidation—glycerol, glyceraldehyde, dihydroxyacetone, glyceric acid, lactic acid, glycolic acid, glyoxylic acid, oxalic acid, tartronic acid, and mesoxalic acid—were analyzed by high-performance liquid chromatography (HPLC) and quantitative ¹³C nuclear magnetic resonance (NMR), in mixtures of known composition. The results obtained were concordant with the known compositions tested. HPLC was more accurate than quantitative ¹³C NMR for simple mixtures, but ¹³C NMR was required for complex mixtures containing dihydroxyacetone and glycerol, oxalic acid and mesoxalic acid, or glyoxylic acid and tartronic acid, pairs of compounds not well separated or detected by HPLC. As proof-of-concept, an unknown mixture generated by glycerol oxidation was analyzed by HPLC and quantitative ¹³C NMR. The results obtained were concordant and allowed accurate determination of the composition of the sample, which contained mesoxalic acid as the major product, with oxalic acid, tartronic acid, and glyceric acid as by-products.     

Preparation of Highly Active and Stable Perovskite-like Catalyst by Combustion Method: Effect of Complex

Perovskite-like oxides (i.e., LaSrNiO₄) prepared by combustion method with various complexes and amounts are compared and their catalytic performances for CO oxidation are tested. Results indicate that sample prepared with oxalic acid as the complex and 100% in excess of cations shows the best and stable activity for oxidation reaction, suggesting that oxalic acid is a preferential complex in the synthesis of perovskite-like catalyst by combustion method.     

绝缘金属铝基板的制备及介电性能研究

采用阳极氧化的方法分别在浓度2%和4%的草酸体系下对金属铝基板表面进行了绝缘化处理。通过SEM对绝缘膜层进行了研究分析,并测试了膜层的介电性能。结果表明:浓度4%的草酸体系下得到的绝缘膜表面存在直径80nm左右的针状物,它可能是膜表面形成的Al(OH)3水合物。较大浓度的草酸电解液的溶解作用加剧了膜层断面开裂、膜质疏松等缺陷,严重影响着膜层的介电性能。     

在1-乙基咪唑三氟乙酸盐离子液体中合成的聚吡咯对草酸的电催化氧化

The electrochemical oxidation of oxalic acid is important in environmental engineering. In this paper, polypyrrole （PPy） was prepared galvanostatically in an ionic liquid 1-ethylimidazolium trifluoroacetate （HEImTfa） and its electro-catalysis function for the electrochemical oxidation of oxalic acid was investigated by using cyclic voltammetry. The results showed that the electro-catalytic activity of PPy prepared in HEImTfa （PPy-HEImTfa） was greatly improved as compared with that prepared in conventional H2SO4 aqueous solution. Therefore, the use of HEImTfa as growth electrolyte and solvent for electro-polymerization of pyrrole resulted in an electrochemically catalytic film of PPy for the electrooxidation of oxalic acid.     

The effect of surface treatment on oxidation of oxalic acid at nanocrystalline diamond films

The surface investigation of undoped and boron doped nanocrystalline diamond (NCD/BDND) films associated to their electrochemical behavior of oxalic acid after four pre-treatments was studied. The films were produced using Hot Filament CVD technique on Si substrate with a gas mixture of CH₄/H₂/Ar. Surface pre-treatments were carried out to analyze the surface chemical changes induced by hydrogen and oxygen plasma and as well as cathodic and anodic treatments performed in 0.1 mol L^? 1 HClO₄. The films wetting analyzed by contact angle presented a strong dependence of their surface before and after each treatment was also confirmed by the electrochemical response from cyclic voltammograms. Independent of the surface pre-treatments, all the electrodes exhibited response for oxalic acid oxidation, but the electrode submitted to hydrogen plasma presented the lowest starting oxidation potential and the highest current density. Nonetheless, the BDND electrode presented higher oxidation current than that for NCD electrodes, after all pre-treatments studied. The use of square wave voltammetry with BDND electrode treated by hydrogen plasma for the analytical determination of oxalic acid is described. The detection limits of 0.75 μmol was obtained from the linear relationship between the peak currents of voltammograms as a function of the oxalic acid concentrations.     

Synthesis and characterization of PANI nanostructures for supercapacitors and photoluminescence

Polyaniline structures were synthesized through a chemical method using citric acid and oxalic acid as carriers and 5???m size ??-alumina particles as a template. The obtained nano-size pristine products were characterized using X-ray diffraction, infrared spectroscopy, scanning electron microscopy, optical absorption spectroscopy, photoluminescence spectroscopy and cyclic voltammetry (CV). Nanofibrous PANI was obtained with oxalic acid, nanoparticles with oxalic acid and ??-alumina, net-like nanostructures with citric acid and spherical nanoparticles with citric acid and ??-alumina. The high intensity photoluminescence of PANI prepared with oxalic acid as a carrier is possibly due to greater chances of exciton formation resulting from increased ??-electron mobility. Electrochemical studies of PANI electrodes in 2.0?M H₂SO₄ were carried out at various scan rates. The CVs showed rectangular shape with added pronounced oxidation and reduction peaks.     

阳极氧化法制备透明氧化铝薄膜的研究

以铝箔为阳极,石墨为阴极,草酸为电解液,采用二次阳极氧化法制备透明氧化铝薄膜。采用金相显微镜观察一次阳极氧化和二次阳极氧化后氧化铝薄膜的表面形貌,并用X射线衍射仪对氧化铝薄膜结构进行表征。结果表明,二次阳极氧化工艺对氧化铝薄膜的质量有重要的影响。采用退火-除油-浸蚀-电化学抛光-一次阳极氧化-二次阳极氧化工艺,并严格控制工艺参数,可以制备结构良好的透明氧化铝薄膜,且氧化铝薄膜是非晶态结构。