Highly active iridium catalyst for hydrogen production from formic acid

Formic acid(FA) dehydrogenation has attracted a lot of attentions since it is a convenient method for H_2 production. In this work, we designed a self-supporting fuel cell system, in which H_2 from FA is supplied into the fuel cell, and the exhaust heat from the fuel cell supported the FA dehydrogenation. In order to realize the system, we synthesized a highly active and selective homogeneous catalyst Ir Cp*Cl_2 bpym for FA dehydrogenation. The turnover frequency(TOF) of the catalyst for FA dehydrogenation is as high as7150 h~(-1)at 50°C, and is up to 144,000 h~(-1)at 90°C. The catalyst also shows excellent catalytic stability for FA dehydrogenation after several cycles of test. The conversion ratio of FA can achieve 93.2%, and no carbon monoxide is detected in the evolved gas. Therefore, the evolved gas could be applied in the proton exchange membrane fuel cell(PEMFC) directly. This is a potential technology for hydrogen storage and generation. The power density of the PEMFC driven by the evolved gas could approximate to that using pure hydrogen.     

Silver-Cobalt bimetallic nanoparticles to the generation of hydrogen from formic acid decomposition

The fabrication of cost effective heterogeneous catalysts for the release of hydrogen from hydrogen storage materials is the key technological challenge to the fuel-cell based hydrogen economy. Ag-Co bimetallic NPs were fabricated by using sodium dodecyl sulphate (SDS) and sodium borohydride as stabilizing and reducing agents, respectively. Catalytic activity of SDS-Ag-Co was higher than that of SDS free Ag-Co and monometallic (Ag and Co) due to the electron interactions and synergistic effect between the Ag and Co. Ag₁₀-Co₉₀ exhibited the superior catalytic activity, with rate constant of 5.2 × 10^?4 s^?1 at 303 K, activation energy of 46 kJ/mol, activation enthalpy of 44 kJ/mol, activation entropy of ?165 J/K/mol, and turn over frequency of 240 h^?1. The hydrogen generation rate increased and decreased with in increasing temperature, molar concentration of formic acid, presence of sodium formate, and pH, respectively. The kinetic rate equation can be stated as: rate = -d[formic acid]/dt = k_obs[formic acid]^0.99[Ag₅₀Co₅₀]^0.98, k_obs = 2.48 × 10⁷ exp (?5637.96/RT).     

双中心多孔聚合物作为多相催化剂实现CO2在温和条件下高效转化

由于对化石燃料的高度依赖和二氧化碳(CO2)的过度排放,大气中CO2浓度从280 ppm上升到400 ppm左右,导致全球变暖和其他气候问题.在这种情况下,如何有效降低空气中的CO2浓度成为近年来最迫切的研究领域之一.另一方面,作为一种无毒、廉价且丰富的C1资源,CO2也可以转化为各种高附加值的工业产品,如甲酸、一氧化...     

Platinum nanoparticles as recyclable heterogeneous catalyst for selective methylation of amines and imines with formic acid: Indirect utilization of CO2

N-methylation of amines and imines with formic acid as C1 source by easily prepared Pt NPs as heterogeneous catalyst is reported here. Primary, secondary amines and imines were successfully methylated in good to excellent yields under mild conditions. Both aromatic and aliphatic amines could be applied as substrates. Meanwhile, the heterogeneous Pt NPs were capable to be recylcled and reused for 7 times without significant decrease of reactivity. This protocol provided an indirect utilization pathway of CO₂ by using formic acid as C1 source.     

聚苯胺对钯催化甲酸电氧化反应的促进作用

钯基纳米材料是甲酸电氧化反应的优良催化剂.本工作制备了两个系列钯基催化剂,并考察了聚苯胺对钯上甲酸电氧化反应的助催化作用.一种是以聚苯胺为基底,在其表面电沉积钯纳米粒子,制得nPANI/Pd催化剂(n表示聚合苯胺的循环数);另一种是直接在商业Pd/C催化剂表面电聚合苯胺,制得Pd/C/nPANI催化剂.结果显示,聚苯胺单独存在时对甲酸电氧化反应没有催化活性,但其可对钯上甲酸电氧化反应呈现明显的促进作用,且促进作用与聚苯胺的厚度(聚合循环数)密切相关.在两个系列催化剂中,15PANI/Pd和Pd/C/20PANI显示出最高的催化性能.15PANI/Pd中钯的质量比催化活性是纯钯催化剂的7.5倍; Pd/C/20PANI中钯的质量比催化活性和本征催化活性分别是商业Pd/C催化剂的2.3和3.3倍.钯催化性能的提升与聚苯胺和钯纳米粒子间的电子效应有关.     

多孔骨架固定分子催化剂催化CO2加氢制备甲酸研究进展

近年来, 大气中CO₂含量急剧增加, 导致了严重的温室效应. 将CO₂作为C1资源转化为燃料或精细化学品引起了越来越多的关注. 开发高效、 稳定、 可回收利用的催化剂成为CO₂资源化利用的关键. 在众多的CO₂加氢催化剂中, 功能性多孔骨架材料固定型分子催化剂展示出优异的性能, 成为研究的热点之一. 功能性骨架材料, 如多孔有机聚合物(POPs)、 共价有机骨架(COFs)和金属有机骨架(MOFs), 具有比表面积大、 热稳定性高和可调性等特点, 在设计合成催化剂方面发挥着重要作用. 本文介绍了POPs/COFs/MOFs多孔骨架材料固定分子催化剂的开发及在催化CO₂合成甲酸领域的最新进展.     

Synthesis of Pd/C catalysts with designed lattice constants for the electro-oxidation of formic acid

Pd/C catalysts with designed lattice constants were synthesized for the electro-oxidation of formic acid. By changing the solvents in the preparation procedure, it was demonstrated that the different lattice constants of Pd crystallites could be controlled as desired. The varied lattice constants may be attributed to the difference in the interactions between solvents and PdCl₂. It was found that the lattice constant had an obvious effect on the electro-catalytic performance of Pd.     

Synergistic enhancement of formic acid electro-oxidation on PtxCuy co-electrodeposited binary catalysts

A propitious binary catalyst composed of Pt and Cu which were electrodeposited simultaneously onto a glassy carbon (GC) substrate was recommended for the formic acid (FA) electro-oxidation reaction (FAOR); the principal anodic reaction in the direct FA fuel cells (DFAFCs). The simultaneous co-electrodeposition of Pt and Cu in the catalyst provided an opportunity to tune the geometric functionality of the catalyst to resist the adsorption of poisoning CO at the Pt surface that represented the major impediment for DFAFCs marketing. The catalytic activity of the catalyst toward FAOR was significantly influenced by the (Pt⁴⁺/Cu²⁺) molar ratio of the electrolyte during electrodeposition, which also affected the surface coverage of Pt and Cu in the catalyst. Interestingly, with a molar (Pt⁴⁺/Cu²⁺) ratio of (1:4), the catalyst sustained superior (3.58 compared to 0.65 obtained at the pristine Pt/GC catalyst) activity for FAOR, concurrently with up to four-times (0.73 compared to 0.18 obtained at the pristine Pt/GC catalyst) improvement in the catalytic tolerance against CO poisoning. This associated, surprisingly, a negative shift of ca. 336 mV in the onset potential of FAOR, in an indication for the competitiveness of the catalyst to minimize superfluous polarizations in DFAFCs. Furthermore, it offered a better (ended up with 20% loss in the activity) stability for continuous (1 h) electrolysis than pristine Pt/GC catalyst (the loss reached 35%). The impedance and CO stripping measurements together excluded the electronic element but confirmed the geometrical influence in the catalytic enhancement.     

Quantitative determination of formic acid in apple juices by H NMR spectrometry

A quantitative determination method of formic acid in apple juices is proposed by means of the proton nuclear magnetic resonance (¹H NMR) technique. Formic acid gives a singlet signal at the 8.2-8.4 ppm interval of the spectrum, and its area is used to determine the concentration of the acid. 1,3,5-Benzenetricarboxylic acid is added to the juice as an internal standard. Since the chemical shift of both species varies with the pH, ascorbic acid is also added to adjust it at 2.74 and to avoid the overlapping of the signals. Recoveries between 95 and 109% are obtained when the standard addition method is applied to the juices of five different cider apple varieties. The coefficient of variation obtained is 3.9% for intra-day repeatability (n = 5), and 4.6% for inter-day repeatability (n = 10). The limit of detection is 1.49 mg/l, calculated from “3S_y/x + intercept”. The described method is direct and no previous derivatization is needed.     

Mesoporous silica-supported V-substituted heteropoly acid for efficient selective conversion of glycerol to formic acid

V-substituted polymolybdenum phosphoric acid (PV_xMo) supported on mesoporous silica was prepared and investigated as a catalyst for the oxidation of glycerol to formic acid in a batch operation. Different synthetic methods for PV_xMo supported on mesoporous silica were compared. Detailed characterizations of the final products were carried out by N₂ adsorption and desorption, XRD, HR-TEM, SEM, ICP-OES, XANES, NH₃-TPD, and FTIR to identify the chemical properties and the porous structure of silica-supported PV_xMo, as well as the strong interactions between PV_xMo with the silica skeleton. These critical properties explain the bifunctionality of silica-supported PV_xMo as a catalyst for the selective oxidation of glycerol to formic acid with standing stability.     

DFT法研究HCOOH在Pd/WC(0001)上的分解机理（英文）

作为便携式电子设备的动力源,直接甲酸燃料电池(DFAFC)具有燃料跨界范围小、电动势大、甲酸无毒、低温下功率密度大等优点,因而引起了人们的极大兴趣.DFAFC商业化的主要挑战之一是阳极电催化剂材料的高成本和低CO耐受性.阳极通常需要高负载的贵金属电催化剂(Pt或Pd)氧化甲酸(HCOOH)以获得所需的电能.完全电氧化甲酸在Pt和Pd表面上会产生强吸附的CO,从而降低了Pt或Pd催化剂的活性.Pt和Pd储量少且价格昂贵,减少Pt和Pd含量且保持催化性能的燃料电池催化剂一直是研究者的奋斗目标.本文用周期性密度泛函理论(DFT)系统地研究了WC负载的单分子层Pd(Pd/WC(0001))催化剂对甲酸的分解机理,这可为所需的反应路径设计、筛选催化剂提供指导.Trans-HCOOH通过C–H, O–H, C–O键的活化发生分解.关于吸附,确定了可能反应中间体的最稳定吸附构型.trans-HCOOH, HCOO, mHCOO, cis-COOH, trans-COOH, CO, H₂O, OH和H的吸附过程是化学吸附,而cis-HCOOH和CO₂与Pd/...     

MoS2/Zn3In2S6复合光催化剂构建:高效提升可见光驱动甲酸制氢

虽然传统的化石燃料依然能够满足当今快速工业化发展对能源的巨大需求,但其固有的不可再生性及其燃烧产物对环境的污染,严重阻碍了其在生产和生活中的广泛使用.因此,可持续清洁能源开发的研究已快速成为人类研究的热点.氢是一种具备高热值、可持续等优点的清洁能源,也兼备成本及污染低等优势.甲酸(FA)以其无毒、低成本、氢含量高等优点,是一种潜在的热门储氢材料,而可见光占太阳光谱的43%左右.因此,开发高效可见光催化剂驱动FA制氢将是一种应对能源危机的有效途径.许多传统光催化剂已被用于可见光催化FA制氢,但制备成本高、过程复杂、条件苛刻及可见光响应差、稳定性和选择性差、有毒气体释放等缺点严重限制了其光催化性能.光催化研究关键之一是实现光生电荷的高效率分离和转移,从而光催化剂光催化性能的提高.Zn3In2S6(ZIS6)因具有强可见光吸收、稳定性好及环保等特点正迅速成为光催化剂半导体的“明星”,常与助催化剂(如贵金属Pt、Au、Pd等)复合形成异质结以促进光生载流子分离和提高其光催化活性,但制备成本高等因素却严重限制其发展.将成本低、化学稳定性好的MoS2与其它半导体耦合也是提高半导体光催化剂性能的有效手段之一,但高温、热处理时间长及有毒气体释放等却成了制约因素.本文选用价格低廉的反应前驱体,采用简单的一锅法水将MoS2紧密地结合到ZIS6的表面,热制备了一系列含有不同质量百分比MoS2的MoS2/Zn3In2S6(MoS2/ZIS6)复合光催化剂,有效降低了制备成本和有毒气体(H2S)的释放.结果表明,可见光照射下(λ>400 nm),MoS2的引入可大大提高ZIS6光生电荷分离效率及制氢活性,尤其以0.5%MoS2/ZIS6性能最优,光催化制氢速率高达74.25μmol·h^-1(量子效率约2.9%),约ZIS6的4.3倍(17.47μmol·h^-1).XRD结果表明,MoS2/ZIS6样品中含有无定型MoS2紧密固定在晶型ZIS6片状结构表面,未影响ZIS6晶型,SEM表征也证实了此结果.随后的TEM、HRTEM及EDX结果也进一步确认了各组成元素的存在和分布.采用XPS对元素化学环境进行了分析,通过S和Mo元素的成键能变化证实了MoS2和ZIS6间的紧密接触.UV-Vis DRS测试表明,MoS2/ZIS6可以利用可见光在适当带隙的基础上进行光催化制氢.通过BET、PL和电化学技术研究了比表面积、光生电荷分离和传递速率等对光催化性能的影响.最终,结合上述表征结果成功阐述了可见光驱动FA制氢的反应机理.     

Aluminum(III) triflate-catalyzed selective oxidation of glycerol to formic acid with hydrogen peroxide

Glycerol is a by-product of biodiesel production and is an important readily available platform chemical. Valorization of glycerol into value-added chemicals has gained immense attention. Herein, we carried out the conversion of glycerol to formic acid and glycolic acid using H₂O₂ as an oxidant and metal (III) triflate-based catalytic systems. Aluminum(III) triflate was found to be the most efficient catalyst for the selective oxidation of glycerol to formic acid. A correlation between the catalytic activity of the metal cations and their hydrolysis constants (K_h) and water exchange rate constants was observed. At 70 °C, a formic acid yield of up to 72% could be attained within 12 h. The catalyst could be recycled at least five times with a high conversion rate, and hence can also be used for the selective oxidation of other biomass platform molecules. Reaction kinetics and ¹H NMR studies showed that the oxidation of glycerol (to formic acid) involved glycerol hydrolysis pathways with glyceric acid and glycolic acid as the main intermediate products. Both the [Al(OH)_x]ⁿ⁺ Lewis acid species and CF₃SO₃H Brønsted acid, which were generated by the in-situ hydrolysis of Al(OTf)₃, were responsible for glycerol conversion. The easy availability, high efficiency, and good recyclability of Al(OTf)₃ render it suitable for the selective oxidation of glycerol to high value-added products.     

多孔有机聚合物负载钯作为高效C-C偶联反应多相催化剂

Pd催化的C-C均相偶联反应,如Suzuki,Heck和Sonogashira广泛应用于有机合成、药物化学、材料科学等领域.均相催化剂具有难分离和不易循环利用的缺点,因而其应用有所受限.因此,开发具有高稳定性和高活性以及可循环性的Pd负载的多相催化剂具有重要意义.多孔有机聚合物具有独特的多级孔结构以及良好的稳定性,因而为制备新型的多相催化剂提供了可能.本文将乙烯基修饰的1,10-菲罗啉有机配体与二乙烯基苯共聚得到了菲罗啉功能化的多孔有机聚合物(PCP-Phen),负载Pd(OAC)2后所制催化剂(Pd/PCP-Phen)在Suzuki,Heck和Sonogashira等偶联反应中表现出优异的活性、选择性和稳定性.固体核磁和红外结果表明所合成的多孔有机聚合物具有1,10-菲罗啉有机配体;热重分析显示该聚合物具有较高的热稳定性;N2吸附测试表明该多孔有机聚合物及其钯负载物均具有丰富的介孔结构(11.2和7.3 nm)和大的比表面积;扫描电镜和透射电镜结果确也证实了它们具有丰富的介孔结构.X射线光电子能结果表明,Pd/POP-Phen催化剂中Pd 3d5/2和Pd 3d3/2的结合能分别为337.6和343.1 eV,略低于Pd(OAc)2的(338.6和343.8 eV).同时,该催化剂的N 1s结合能为400.0 eV,高于POP-Phen的399.3 eV.由此可见,该催化剂中菲罗啉有机配体与Pd物种有很强的配位作用.将得到的Pd/POP-Phen催化剂用于Suzuki,Sonogashira以及Heck反应.对于Suzuki反应,当以溴苯和苯硼酸为底物,乙醇和水(2∶3)为溶剂时,反应30 min联苯的产率高于99％;而在菲罗啉和醋酸钯(Pd/Phen)混合均相催化剂作用下,同样条件下转化率仅为1.7％.可见,Pd/POP-Phen多相催化剂在Suzuki反应中的催化活性高于均相催化剂.更为重要的是,该催化剂在循环使用五次后并未见明显的失活,且在反应液中也未检测到Pd,说明反应中金属物种基本上没有流失,与Pd/POP-Phen 多相催化剂的高稳定性一致.当将反应物扩展到多种不同底物时,Pd/POP-Phen催化剂均显示出非常优异的催化性能.在Sonogashira和Heck反应中,该多相催化剂也有非常好的催化性能.在碘苯和苯乙炔为反应物的Sonogashira反应中,于120℃进行30 min后,转化率即可达99％以上,高于Pd/Phen均相催化剂(93％);且该反应在没有CuI参与下也可以进行,从而避免了副产物二苯炔的形成.在碘苯和丙烯酸甲酯为底物的Heck反应中,于130℃只需反应20 min转化率可达到＞99％,也优于相应的均相催化剂.循环实验表明,该催化剂具有很高的稳定性.Pd/POP-Phen多相催化剂表现出高于均相催化剂的活性,主要原因归于催化剂孔道中相对较高的反应物浓度.在多相催化反应中,因为其丰富的多孔结构对反应物具有很强的富集作用,从而使得多相催化剂里的反应物浓度大大高于均相催化剂.例如,在Suzuki反应中,溴苯在多相催化剂中的浓度是均相催化体系的14倍.     

Low temperature design of titanium dioxide anatase materials decorated with cyanuric acid for formic acid photodegradation

The influence of cyanuric acid (CA) on the structural, textural, electronic, morphological properties and the photocatalytic activity of titanium dioxide materials (TNCA) were herein evaluated. TNCAs samples were prepared through the sol gel method. The novelty of this work that cyanuric acid; the so far most recalcitrant molecule, is used here as reservoir of nitrogen. The synthesis of TNCAs nanomaterials are performed at low temperature in presence of quaternary ammonium as co-catalyst for anatase growth. Samples were characterized by means of nitrogen adsorption-desorption isotherms at 77 K, X-ray diffraction (XRD), Infrared (ATR), Raman, diffuse reflectance ultraviolet-visible, photoluminescence (PL) and electron paramagnetic resonance (EPR) spectroscopies, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The photocatalytic activities of TNCAs and their free counterpart nanomaterials were then evaluated in the photocatalytic degradation of formic acid (FA) as model molecule under UV.X-ray and Raman show success of anatase phase formation at low temperature without any post-calcination. IR-ATR analysis confirms CA grafting onto TiO₂ identified by formation of vibration band between Ti and triazine. SEM mapping shows that C, O, Ti, and N are homogeneously distributed in the nanomaterial. Nitrogen adsorption-desorption measurements at 77 K show developed textural properties; the heat of N₂ adsorption seems to be affected by CA loading. PL and UV-visible spectroscopies show simultaneously (i) electron trapping by the oxygen vacancy identified by Raman spectroscopy by redshift of Eg1 mode and (ii) the hole is confined by nitrogen. Therefore, the excited electron can move from TiO₂ VB to the new sublevels initiated by the introduction of nitrogen which results in quenching of the photoluminescence intensity. The photocatalytic activity of the various TNCAs nanomaterials increases versus CA loading. The highest k_LH of TNCA2 (5 wt%) could be explained by short migration time conjugated with lower bulk recombination of the photogenerated electron hole.     

Short-time maximum entropy method analysis of molecular dynamics simulation: Unimolecular decomposition of formic acid

We performed spectral analysis by using the maximum entropy method instead of the traditional Fourier transform technique to investigate the short-time behavior in molecular systems, such as the energy transfer between vibrational modes and chemical reactions. This procedure was applied to direct ab initio molecular dynamics calculations for the decomposition of formic acid. More reactive trajectories of dehydrolation than those of decarboxylation were obtained for Z-formic acid, which was consistent with the prediction of previous theoretical and experimental studies. Short-time maximum entropy method analyses were performed for typical reactive and non-reactive trajectories. Spectrograms of a reactive trajectory were obtained; these clearly showed the reactant, transient, and product regions, especially for the dehydrolation path.     

多孔有机含BINAP聚合物负载Rh催化剂在苯乙烯不对称氢甲酰化中的应用:柔性手性口袋对产物对映体选择性的提高作用

不对称氢甲酰化是合成具有单一光学活性物质(如光学活性的醛、α-氨基酸和醇等)最为重要的反应之一.尽管不对称氢甲酰化反应的研究超过40年,但仍然是催化体系中具有挑战性的课题.该反应涉及到产物的化学选择性、立体选择性和对映体选择性的优化.目前,在Rh催化体系中,使用磷-亚磷酸酯手性配体或双亚磷酸酯配体可以在不对称氢甲酰化反应中取得优异的催化性能.然而在Rh/手性双膦配体催化体系中,不对称氢甲酰化反应性能通常很低.以BINAP配体为例,负载Rh金属后,在催化苯乙烯不对称氢甲酰化反应中,产物的ee值只有25％.同时,由于均相催化体系存在催化剂回收和产物提纯等问题,因此有必要研究多相不对称氢甲酰化反应催化剂.本文使用乙烯基修饰的BINAP配体5,5'-divinyl-BINAP与具有不同结构的共聚单体二乙烯基苯或1,3,5-三乙烯基苯基苯共聚,得到具有不同孔结构的聚合物Poly-1和Poly-2.为了比较,利用线性共聚单体乙二醇二甲基丙烯酸甲酯与乙烯基BINAP共聚得到聚合物Poly-3.上述三种聚合物材料负载金属Rh后,用作苯乙烯不对称氢甲酰化反应的催化剂.固体13C核磁分析表明,三种聚合物材料负载金属后仍然保持较为稳定的C骨架结构.通过31p核磁可以看到,嵌入在材料骨架中的BIANP仍然保持未被氧化的状态.N2物理吸附结果发现Poly-1和Poly-2具有较大的比表面积和孔体积,而Poly-3的比表面积最小.热重分析显示,这些材料具有较高的热稳定性.在不同反应溶剂中催化剂活性差异较大.通过优化反应温度和合成气压力后,催化剂Rh/Poly-1在80℃和0.2 MPa下产物的对映体选择性可高达58.9％,支链醛与直链醛的比值为8.5;而在相同反应条件下,均相催化剂Rh-BINAP的ee值仅为35.3％,但高于Rh/Poly-3.这是由于三个多相催化剂骨架中BINAP周围环境不同所致.前两个催化剂中,BINAP与空间位阻较大的单体相连接,使得反应底物按照特定方向与催化活性位点接触,形成了类似于手性口袋的结构.而Rh/Poly-3中,BIANP周围是线性的共聚单体,不能形成有效的手性口袋结构.Rh/Poly-1重复使用7次后,催化活性没有显著下降.拓展X射线吸收精细结构表征结果表明,Rh/Poly-1催化剂使用前没有Rh-Rh键存在,但经重复使用后,Rh金属部分聚集,生成了Rh-Rh键.球差电镜照片也证实了这一点.     

Nanostructured platinum as an electrocatalyst for the electrooxidation of formic acid

Nanostructured platinum prepared by the chemical reduction of hexachloroplatinic acid dissolved in aqueous domains of the liquid crystalline phases of oligoethylene oxide surfactants, was examined as an electrocatalyst for the electrooxidation of formic acid. The electrocatalytic properties of the catalyst combining highly specific surface areas and a periodic mesoporous nanostructure were accessed in sulfuric acid solution containing 0.5 mol dm⁻³ formic acid using cyclic voltammetry (CV) and chronoamperometry. The electrocatalytic activity of the material at 60 °C, is characterised by a mass activity of 8.6 A g⁻¹ and a specific surface area activity of 26 μA cm⁻² at 0.376 V (vs. RHE). The resistance to CO poisoning was found to depend upon electrode potential. At hydrogen adsorption potentials, the material is easily poisoned, while the material shows high resistance to CO poisoning at potentials positive of the hydrogen region. These facts suggest that the decomposition of HCOOH on the mesoporous platinum is likely to proceed through a dual-path mechanism and the high surface area material is a potential electocatalyst towards the electrooxidation of small organic molecules.     

Rhodium nitrosyl catalysts for CO2 hydrogenation to formic acid under mild conditions

A new synthetic protocol for catalysing CO₂ hydrogenation to formic acid under mild conditions is reported, and the CO₂ hydrogenation is efficiently achieved by dcpe‐rhodium‐nitrosyl catalyst precursors, Rh(NO)(dcpe) (1) (dcpe = 1,2‐dicyclohexylphosphinoethane) and Rh(III)(NO)(dcpe)Cl₂ (2). The catalytic activity of 1 is noteworthy for being able to proceed in the absence of protic conditions. Compound 2 is characterized by NMR, IR and X‐ray crystallography. In particular, 2 is observed to bear a bent NO ligand with a Rh–N–O angle of 115.7(3)°, representing one of the smallest M–N–O angles known. Copyright © 2012 John Wiley & Sons, Ltd.     

离子排斥色谱法测定甘油催化氧化产物中的H2CO3和HCOOH

建立了测定甘油催化氧化产物中H2CO3和HCOOH的离子排斥色谱分析方法。采用离子排斥柱分离,分别用纯水和4 mmol/L HCl作流动相进行H2CO3和HCOOH的分析。检测方式为非抑制电导检测。实验结果显示,H2CO3和HCOOH工作曲线的线性范围为2～100 mg/L和6.23～124.6 mg/L,检出限分别为0.45 mg/L和2.49 mg/L(S/N=3)。H2CO3的保留时间和峰面积的相对标准偏差分别为0.07%和4.0%,HCOOH的保留时间和峰面积的相对标准偏差分别为0.09%和2.2%。方法已用于甘油催化氧化产物中H2CO3和HCOOH的分析。