锰酸锂中锰含量测定方法改进

目前锰酸锂中锰含量的测定采用行业标准YS/T 677-2008《锰酸锂》中的硫酸亚铁铵滴定法。该方法采用磷酸和硝酸溶样,现象不易观察;且使用高腐蚀性、强刺激性的高氯酸作为氧化剂,对操作者要求高。笔者采用硝酸铵作为氧化剂,用盐酸溶样,现象明显,且硝酸铵常温下性质稳定,使操作更为安全。经对比实验,两种方法测试结果相同,完全可用硝酸铵氧化法替代高氯酸氧化法测定锰酸锂中锰的含量。     

过硫酸铵氧化容量法测定高锰钢中的锰含量

本文研究了过硫酸铵氧化法测定高锰钢中的锰含量时,磷酸用量,硫酸用量,以及最难以控制的溶样温度和酸度,氮氧化物黄烟的排出等测定条件与测定结果之间的关系,提出了过硫酸铵氧化法测定高锰钢中的锰含量的方法。     

ICP-OES法测定高锰钢衬板中锰含量

研究了电感耦合等离子体发射光谱仪(ICP-OES)法测定衬板中锰含量的应用性.通过对分析测试线、称样量、试样溶解、谱线干扰的研究,实验结果表明选取锰元素257.611nm谱线,铁基体打底,配制合适的标准曲线,利用电感耦合等离子体发射光谱仪能够快速准确的测定衬板中锰含量.结果与高锰钢标准物质标准值相吻合,结果的相对标准偏...     

汽油中锰含量测定影响因素讨论

对按汽油中锰含量的测定方法 SH/T0711-2002《原子吸收光谱法测定汽油中锰含量》测定的结果影响因素一一分析,对分析准确度进行考察。实验结果表明,曲线绘制、标样选择、回收率等因素都能影响分析结果的准确度,对日常检测锰含量在0.25-26 mg/L范围内的汽油需要注意的方面,解决了汽油中锰含量测定不准的难题。     

容量法测定微量元素叶面喷施肥中锌、锰含量

探索了用容量法测定微量元素叶面喷施肥中锌、锰含量的分析条件：样品经硝酸和高氯酸处理后,用EDTA、氯化锌反滴定法测定锌、锰合量,再用硝酸铵法测定锰含量,总量减去锰含量即得锌含量。     

汽油锰含量测定影响因素的考察

文章运用正交试验设计法，确立原子吸收光谱法测定汽油中锰含量的最佳操作条件，考察了汽油中的烯烃、甲基叔丁基醚、乙醇、其它金属元素以及光照等因素对测定结果的影响。考察结果表明，正常情况下，成品汽油中的烯烃、甲基叔丁基醚、乙醇及其它共存金属元素对锰含量测定结果并无影响，但是光照对锰含量测定结果影响较大，在对含锰汽油进行取样及储存时一定要注意避光。     

原子吸收法测定循环醋酸中钴锰含量

介绍了原子吸收法测定PTA生产过程的循环醋酸中钴锰含量的方法 ,并把用该法测定的结果与X 射线荧光法测定结果进行比较 ,结果表明 ,前者精密度好 ,准确性高 ,速度快 ,杂质干扰小 ,完全可代替后者     

过硫酸铵分光光度法测定复混肥料中锰含量

介绍了用过硫酸铵分光光度法测定复混肥料中锰含量的方法。结果表明，锰含量在0～100μm／100ml，范围内符合比尔定律，测定的结果准确，精密度、灵敏度均较高，且操作简便。该方法与高碘酸钾法测定数值基本吻合。     

ICP法测定锰酸锂中铁含量方法改进

电感耦合等离子体发射光谱法（ICP法）测定锂离子电池正极材料锰酸锂中铁含量,通过采用标准加入法代替标准曲线法以消除基体干扰、通过选择合适的谱线消除背景干扰以及称取适量的样品来保证测量的准确。用改进后的ICP法得到的测量结果与分光光度法测量结果进行比较,可知ICP法测定锰酸锂中铁含量方法可行、测定结果可信。     

氮化硅锰中锰的测定

探讨磷酸用量、高氯酸用量、冒烟时间以及加热温度四个因素对硫酸亚铁铵滴定法测定氮化硅锰中的锰含量测定结果的影响。采用正交试验找出各因素对测定结果的影响主次关系以及最优条件。结果表明,影响硅锰合金中锰含爨测定的各因素的主次关系是：加热温度〉冒烟时间〉高氯酸的用量〉磷酸的用量。最优的分析条件是磷酸的用量是20mL,高氯酸的用量是2mL,冒烟时间是230s,加热温度是240℃。该方法简单、方便,满足氮化硅锰中锰的测定。     

PTA氧化催化剂技术及其应用

PTA氧化生产采用钴锰溴三元复合催化体系,现采用多种复合形态的催化剂。笔者综合比较固态的钴锰醋酸盐、溶液态钴锰溴催化剂及溶液态钴锰溴化物复合催化剂。分析表明这3种形态的催化剂催化性能相当,PTA生产的单位消耗相近;溶液态钴锰溴化物复合催化剂使用方便且制造成本较低。     

Electrodeposition of ternary nickel—iron—cobalt alloys from acetate bath

Ternary nickel—iron—cobalt alloys of wide range composition have been deposited from acetate baths under a variety of conditions and the optimum conditions established are: nickel acetate 0.2828 M, ferrous sulphate 0.0359 M, cobalt acetate 0.2828 M, boric acid 0.1617 M, ascorbic acid 0.0056 M, pH 5.0, cd 1.5 A/dm² and temperature 30°. The bath gave bright, smooth and adherent deposits. Iron and cobalt contents decreased with an increase in cd and pH, X-ray studies of the deposits revealed fcc structure within the composition range studied (43.6–54.0% Ni). The results indicate that acetate bath can be successfully employed for plating purposes.     

Co/Mn/Zr复合催化剂催化甲苯液相氧化

以乙酰丙酮锆或乙酸锆与乙酸钴和乙酸锰制备乙酸钴/乙酸锰/乙酰丙酮锆或乙酸锆(Co/Mn/Zr)三元复合催化剂。比较乙酸钴(Co)、乙酸钴/乙酸锰(Co/Mn)和Co/Mn/Zr催化剂体系对甲苯液相氧化反应的催化性能。结果表明:在催化剂中添加Zr可以降低反应温度,提高甲苯转化率和苯甲酸选择性。与乙酸锆相比,采用乙酰丙酮锆制得的Co/Mn/Zr具有较好的催化活性。在Co,Mn和Zr物质的量之比为5 5 1,Co与甲苯的物质的量之比为1 10 000,溶剂乙酸与甲苯质量比为1 2.3,反应温度160℃和反应压力1.4 MPa的条件下反应3 h后,苯甲酸选择性和甲苯转化率分别为80.2%和15.4%。     

The effect of copper,managanese and cobalt acetates on the autoxidation oftrans-9,trans-11-octadecadienoic acid in 90% v/v aqueous acetic acid

The autoxidation oftrans-9,trans-11-octadecadienoic acid in 90% v/v aqueous acetic acid has been studied, at 80 C, with and without copper, manganese and cobalt acetate. The initial 9,11-octadecadienoic acid concentration was 0.05 M in most of the experiments. The metallic acetate concentrations were 10⁻⁵ to 10⁻² M. Copper and manganese acetates retard the autoxidation. With copper acetate, this retardation involves both the induction period and the rapid autocatalytic stage. Manganese acetate prolongs the induction period. A slightly lowered rate is observed at low cobalt acetate concentrations (∼10⁻⁵ M), but higher cobalt acetate concentrations clearly accelerate the autoxidation.     

锰卟啉-醋酸钴复合催化体系对甲苯氧气氧化的催化作用

研究了在无溶剂体系中,对氯四苯基锰卟啉［T(p-Cl)PPMnCl］和醋酸钴［Co(OAc)2］复合催化下,空气氧化甲苯制苯甲醛、苯甲醇和苯甲酸的新工艺。实验发现,T(p-Cl)PPMnCl/Co(OAc)2为复合催化剂时比单独使用T(p-Cl)PPMnCl 或Co(OAc)2时有更高的甲苯转化率和苯甲醛、苯甲醇、苯甲酸的收率,表现出明显的复合催化作用。研究表明,反应温度、反应时间和催化剂比例对T(p-Cl)PPMnCl/Co(OAc)2的复合催化效果有影响。     

氨-碳酸盐法分离PTA废渣中的钴和锰

精对苯二甲酸（PTA）生产中的废钴锰催化剂中钴低锰高,常用的钴锰分离方法一般不适用,分离钴锰时非常容易互相夹带,导致分离不完全。本文采用氨-碳酸盐法分离PTA废渣浸出液中的钴和锰。在正交试验的基础上,以钴剩余率和锰沉淀率作为考核指标,考察了碳酸盐的种类、反应时间、反应温度、搅拌速度、氨的用量和碳酸盐的用量等因素对钴、锰分离效果的影响。实验结果表明,在氨-碳酸钠、氨-碳酸铵、氨-碳酸氢铵3种溶液中,最佳搅拌速度、反应时间、反应温度分别为200r/min、8h和20℃,氨的最佳用量分别为理论化学反应计量的1.9倍、1.4倍和1.7倍,碳酸盐的用量分别为理论化学反应计量的1.0倍、1.3倍和1.3倍。在最佳反应条件下,氨-碳酸钠、氨-碳酸铵、氨-碳酸氢铵3种溶液中,钴的最大剩余率分别可达到96.0%、99.8%和99.5%,锰沉淀率均可达到100%。     

Transition metal catalyzed oxidative aging of low density polyethylene: effect of manganese (III) acetate

The paper discusses the effect of manganese (ІІІ) acetate in the degradation of low density polyethylene (LDPE). Stearic acid has been used as a dispersion promoter to circumvent non-uniform dispersion of inorganic compound like manganese (ІІІ) acetate in LDPE. A detailed study has been made to investigate the effect of dispersion promoter on degradation of LDPE. The combined effect of dispersion promoter and manganese (ІІІ) acetate has been studied in accelerated aging of LDPE. Masked degradation of LDPE has been noted in presence of natural rubber (NR). The degradation processes of LDPE eventually have been observed to follow different mechanistic pathways in presence of dispersion promoter and transitional metal catalyst. At an optimized condition of time and temperature, LDPE has been found to be degraded into a semi-solid state in combined presence of manganese (ІІІ) acetate and the dispersion promoter. The Arrhenius equation has been adopted to predict the life time of the LDPE having different amount of manganese (III) acetate.     

Liquid-phase p-t-butyltoluene autoxidation enhanced by electrochemistry: Activation of the catalytic effect of cobalt acetate

The autoxidation of p-t-butyltoluene (TBT) at 80 °C in the liquid phase is carried out with an initial mixture of cobalt(III) and cobalt(II) acetate in an acetic acid solution. The autoxidation kinetics of TBT is appreciably accelerated by electrolysis with a anodic current density of 62.5 A m^–2. The electrolysis increases the concentration of cobalt(III) acetate, the actual catalyst of the autoxidation reaction. The end product of oxidation is p-t-butylbenzoic acid (TBBA). p-t-Butylbenzaldehyde (TBBZ) is an intermediary whose concentration passes through a maximum. The oxidation experiments with TBT were performed with total cobalt acetate concentrations ranging from 0.0188 to 0.169 mol dm^–3. An increase in total cobalt acetate concentration favours the electrochemical regeneration of Co^III and slightly improves the TBBZ selectivity. The duration of TBT oxidation into TBBA is reduced by a factor of 5 compared with a reaction without electrolysis.     

Liquid phase oxidation of cyclohexanone to adipic acid by air in acetic acid solution

The liquid phase oxidation of cyclohexanone to adipic acid by air in the presence of acetic acid as a solvent and cobalt acetate or manganese acetate as a catalyst was investigated at a temperature of 60 to 100 °C, and at essentially atmospheric pressure. Succinic acid and glutaric acid were the major by-products. Under the most suitable set of conditions (cyclohexanone, 1.2 M ; cobalt acetate, 7 × 10^?3 M ; superficial air velocity, 2.5 cm/s, temperature, 80 °C; period of reaction, 5 h), the overall conversion of cyclohexanone was 61 % and the yield of adipic acid and diabasic acids was 69.3% and 85.6% respectively.     

Effects of cobalt precursor on pyrolyzed carbon-supported cobalt-polypyrrole as electrocatalyst toward oxygen reduction reaction

A series of non-precious metal electrocatalysts, namely pyrolyzed carbon-supported cobalt-polypyrrole, Co-PPy-TsOH/C, are synthesized with various cobalt precursors, including cobalt acetate, cobalt nitrate, cobalt oxalate, and cobalt chloride. The catalytic performance towards oxygen reduction reaction (ORR) is comparatively investigated with electrochemical techniques of cyclic voltammogram, rotating disk electrode and rotating ring-disk electrode. The results are analyzed and discussed employing physiochemical techniques of X-ray diffraction, transmission electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, inductively coupled plasma, elemental analysis, and extended X-ray absorption fine structure. It shows that the cobalt precursor plays an essential role on the synthesis process as well as microstructure and performance of the Co-PPy-TsOH/C catalysts towards ORR. Among the studied Co-PPy-TsOH/C catalysts, that prepared with cobalt acetate exhibits the best ORR performance. The crystallite/particle size of cobalt and its distribution as well as the graphitization degree of carbon in the catalyst greatly affects the catalytic performance of Co-PPy-TsOH/C towards ORR. Metallic cobalt is the main component in the active site in Co-PPy-TsOH/C for catalyzing ORR, but some other elements such as nitrogen are probably involved, too.