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

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

煤及油母中常见cxxns的解离能

煤及油页岩中除了碳、氢和氧原子是主要的组成元素外,氮和硫等杂原子大都以C—X（X=N,S）的键合形式存在,在其结构及转化利用中同样发挥重要的作用。认识C—X的解离能,有助于建立氮、硫热解过程中的迁移模型,丰富对煤及油母中常见化学键性质的认识,对发展高效清洁的能源利用技术至关重要。利用双杂化密度泛函方法,系统研究了煤及油母中典型C—X键的解离能（BDE）范围。研究结果表明,煤及油母中常见C—N和C—S键的BDE值范围分别是154.1-55.7 kcal·mol^-1和83.0-56.6 kcal·mol^-1。在热解过程中,苯硫类自由基以及苯胺类自由基会在初期产生,其次才是巯基、胺类自由基等侧链取代自由基脱落。C—S键的整体BDE值范围比其他类型化学键更低,各类化学键最低BDE值的高低顺序符合O—H〉C—H〉C—C〉C—N〉C—S〉C—O的规律,其中,只有当有PhO·生成时,C—S〉C—O,否则C—O〉C—S

煤及油母中常见cxxns的解离能

煤及油页岩中除了碳、氢和氧原子是主要的组成元素外,氮和硫等杂原子大都以C—X（X=N,S）的键合形式存在,在其结构及转化利用中同样发挥重要的作用。认识C—X的解离能,有助于建立氮、硫热解过程中的迁移模型,丰富对煤及油母中常见化学键性质的认识,对发展高效清洁的能源利用技术至关重要。利用双杂化密度泛函方法,系统研究了煤及油母中典型C—X键的解离能（BDE）范围。研究结果表明,煤及油母中常见C—N和C—S键的BDE值范围分别是154.1-55.7 kcal·mol^-1和83.0-56.6 kcal·mol^-1。在热解过程中,苯硫类自由基以及苯胺类自由基会在初期产生,其次才是巯基、胺类自由基等侧链取代自由基脱落。C—S键的整体BDE值范围比其他类型化学键更低,各类化学键最低BDE值的高低顺序符合O—H〉C—H〉C—C〉C—N〉C—S〉C—O的规律,其中,只有当有PhO·生成时,C—S〉C—O,否则C—O〉C—S

Chirality sensing of tertiary alcohols by a novel strong hydrogen-bonding donor – selenourea

In this paper, a novel type of chiral bisselenourea sensor was first synthesized and used as a strong hydrogen-bonding donor for highly efficient chiral recognition of a diverse range of tertiary alcohols.</p

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