草酸电解合成乙醛酸反应器的研究和模拟

草酸电解还原法生产乙醛酸是一种较有前途的生产方法，对其反应器性能的研究具有重要的理论意义和工业应用价值。 本文首先从平行板电解槽出发，对石墨阴极和碳基催化阴极作了初步研究，并考察了电极材料、电极电位、电解温度、电解液流速对电解反应的电流效率和时空产率的影响，对草酸电解合成乙醛酸工艺有了初步认识。在此基础上，考虑用固定床电解槽来提高时空产率，设计出双阳极室固定床电解槽，使电解的时空产率有了近10倍的提高，但是，在高电流密度时其温度波动较大，要降低温度相当困难。为了进一步改善固定床移热问题，开发出新型阴极冷却反应器，与前人提出的阴极冷却概念相比，其突出优点是冷却剂几乎没有增加反应器的体积，节省了...学位：工学硕士院系专业：化学化工学院化学工程系_化学工程学号：20003300

乙醛酸电合成研究进展

较为全面地总结了乙醛酸制备的技术路线,综合评价其工艺的优缺点;详述了电合成乙醛酸工艺开发方面的情况,总结其最佳工艺条件,提出了存在的问题和今后发展的方向

Electrosynthesis of glyoxylic acid in a static bed reactor with cooled cathode

以过饱和草酸水溶液为阴极液,盐酸溶液为阳极液,在阴极冷却固定床电化学反应器内草酸电解合成乙醛酸。考察了电流密度、电极和电解液温度、阴极材料对合成乙醛酸时空产率和电流效率的影响。结果表明,阴极冷却固定床反应器是一种较理想的反应器,用石墨板作阳极,铅作阴极,电流密度为400.5A/m2,阴极空速u0=0.505m/s,电解温度为20℃左右时,电解1.5h,在阴极可得到质量分数为5.45%的乙醛酸溶液,平均时空产率可达0.12kg/dm3·h以上。Glyoxylic acid was produced by electroreduction of oxalic acid in the static bed reactor with cooled cathode. The cathodic and anodic electrolytes were super-saturated oxalic acid and hydrochloric acid aqueous solutions. The current efficiency and time-space yield of glyoxylic acid were studied under different current densities, temperatures of cathode and electrolyte,materials of cathode. The results indicated that the cooled cathode static bed reactor is an excellent reactor. The average space-time yield of glyoxylic acid is over 0.12 kg/dm~3·h and the concentration of glyoxylic acid can reach 5.45% after 1.5 h electrolysis with cathode of lead and anode of graphite board under conditions of temperature 20℃,superficial flow rate of 0.505 m/s and current density of 400.5 A/m~2 in the cooled cathode static bed reactor.福建省自然科学基金资助项目(F99029

钾促进钴钼耐硫CO变换催化剂的XPS和TPR表征

用 XPS和 TPR谱学表征方法 ,研究钾助剂对负载型 Co-Mo-K-O/γ-Al2 O3水煤气耐硫变换催化剂的作用 .XPS表征显示 ,硫化态催化剂随着钾添加量的增加 ,低价态钼和 S2 - 增加 ,( S-S) 2 - 受抑制 ,( Mo4+ +Mo5 + ) /Mo6 + 质量比为 0 .8～ 1和较多的 S2 - 物种有利于提高催化剂的低温活性 .TPR表征结果示出 ,硫化态及工作态催化剂皆出现α、β 2个吸氢峰 ,可分别归属 Mo6 + → Mo5 + 和 Mo5 + → Mon+ ( n=4 ,3,2 )的还原过程 ;工作态催化剂 α峰峰温较硫化态低 ,β峰为宽峰带低价钼混合峰 ;吸氢峰的大小与催化剂低温活性密切相关

Electrosynthesis of Glyoxylic Acid in a Packed Bed Reactor

以过饱和草酸水溶液为阴极液 ,盐酸为阳极液 ,在固定床电解槽中草酸电还原得到乙醛酸 .考察改变固定床的结构、电解温度及电流密度对生成乙醛酸电流效率和产率的影响 .结果表明 ,以铅粒作阴极 ,石墨板作阳极 ,电流密度 96 .3A·m- 2 ,阴极液空速 0 .5 0 5m·s- 1,电解温度 32℃时 ,在固定床双阳极室内反应 4 5min ,乙醛酸的电流效率仍达到 6 6 .2 % ,浓度 2 .0 2 %Glyoxylic acid was produced by electroreduction of oxalic acid in a packed bed reator.The cathodic and anodic electrolytes were super_saturated oxalic and hydrochloric acid aqueous solutions separated by a super_acid ion_exchange membrane.The current efficiency and yield of glyoxylic acid were studied under different structured packed bed reactors and different electrode materials,temperatures and current densities.The results indicated that the current efficiency of synthsis of glyoxylic acid was over 66.2% and the concentration of glyoxylic acid could reach 2.02% after 45min electrolysis with cathode of lead particles and anode of graphite board under conditions of temperature 32 ℃,superficial flow rate of 0.505 m·s -1 and current density of 96.3 A·m -2 in a packed bed reactor with double_anode cell.作者联系地址：厦门大学化工系,厦门大学化工系,厦门大学化工系,厦门大学化工系 福建厦门361005 ,福建厦门361005 ,福建厦门361005 ,福建厦门361005Author's Address: Dept. of Chem. Engin., Xiamen Univ., Xiamen 361005,Chin

超临界CO_2流体萃取分离乙醛酸的研究

本文通过测定草酸和乙醛酸在不同的温度和压力下在超临界CO2流体中的溶解度,确定超临界CO2流体萃取乙醛酸的工艺条件。在一定的条件下证明利用该工艺的可行性,为进一步研究此方法分离乙醛酸奠定了基础

Investigation on Electrogenerated Active Chlorine from diluted NaCl Solutions at Ti/Pt Anode

以Ti板阴极、Ti/Pt阳极组成无隔膜电解装置,电解低浓度NaCl溶液制得活性氯.研究电解时间、电流密度、氯离子浓度、溶液pH值对活性氯浓度及电流效率的影响.结果表明:电解时间增加,活性氯浓度增加,而电流效率逐渐降低;初始阶段活性氯浓度增加较快,近1 h活性氯浓度趋于稳定;增加氯化钠浓度可提高活性氯浓度和改善电流效率;微酸性电解液有利于提高活性氯浓度.电解过程中,溶液电导率不断降低,pH值变化范围在1之内.Electrogeneration of active chlorine from diluted NaCl solutions was investigated in an undivided cell with Ti/Pt anode and Ti plate cathode.The effects of electrolysis time,current density(i),chloride concentration and pH value on the electrogeneration of active chlorine and current efficiency(CE) were analyzed.Meanwhile,the changing trends of the electrolyte's conductivity(TSD) and pH value in the electrolysis process were discussed.The results showed that the concentration of active chlorine increased with electrolysis time,but the trend became slow.During this process,the current efficiency reduced steadily.When i was 4.93～7.39 mA/cm2,the concentration of active chlorine increased with the increase of i,but no longer increased when the i exceeded 7.39 mA/cm2.The concentration of active chlorine and CE increased with the increase of NaCl concentration,but the increased range reduced.Acidic electrolyte was beneficial to electrogeneration of active chlorine.During the electrolysis,the TSD decreased steadily and the change of pH value did not exceeded 1.作者联系地址：同济大学城市污染控制国家工程研究中心;Author's Address: National Engineering Research Center for Urban Pollution Control,Tongji University,Shanghai 200092,Chin

Electrochemical Reduction Characteristics of Nitrobenzene at the Copper Electrode

应用循环伏安法和线性扫描伏安法研究水溶液中硝基苯在铜电极上的电还原特性及其电还原为苯胺的中间步骤和反应机理.结果表明:铜电极上硝基苯的还原电位在-0.58V和-1.32V左右(vs.SCE),溶液的酸性和碱性均有益于该还原反应的发生;还原过程伴有反应物吸附现象,当硝基苯浓度较大时,还原过程受传质过程控制;随着厌氧程度的提高,还原速率加快.The electrochemical reduction characteristics and transition steps of nitrobenzene aqueous solution at the copper electrode, as well as its reduction mechanism were extensively investigatedby using the techniques such as cyclic voltammetry(CV) and linear scan voltammetry(LSV). The results showed that the reduction peaks of nitrobenzene at the copper electrode were located at 0.58 V and 1.32 V or so (vs. SCE), both acidity and alkalinesolutionsfavoredthe reduction of nitrobenzene. The adsorption of compounds followed by the reduction process, which is controlled by the mass transfer step at higher nitrobenzene concentration. In addition, the higher anaerobic degree led to faster reduction rate.作者联系地址：同济大学城市污染控制国家工程研究中心,同济大学城市污染控制国家工程研究中心,同济大学城市污染控制国家工程研究中心 上海200092 ,上海200092 ,上海200092Author's Address: The National Engineering Research Center for Urban Pollution Control, Tongji Unversity, Shanghai 200092,Chin