Electrocarboxylation of Carbon Dioxide with Polycyclic Aromatic Hydrocarbons Using Ni as the Cathode

Using Ni cathode and Al sacrificial anode, the electrocarboxylation of polycyclic aromatic hydrocarbons (naphthalene, 5‐methylnaphthalene, anthracene, phenanthrene and 1H‐indene) with carbon dioxide (4 MPa) could be successfully performed in an undivided cell containing n‐Bu₄NBr‐DMF supporting electrolyte with a constant current at room temperature, affording the corresponding trans‐dicarboxylic acids in good to excellent yields (62% –90%). Among the examined cathode materials (Ni, Pt, Ag, Cu and Zn), Ni and Pt cathodes exhibited a good catalytic activity for the electrocarboxylations. In addition, the experimental results indicated that electrolytic conditions (conducting salts, electricity, CO₂ pressure and temperature) could also affect the result of the electrocarboxylation. According to the results of the electrocarboxylations and CV (cyclic voltammetry), a possible electrochemical reaction mechanism was also proposed.     

Electrocarboxylation of Acetophenone to 2‐Hydroxy‐2‐phenylpropionic Acid in the Presence of CO2

Electrocarboxylation of acetophenone with CO₂ to obtain 2‐hydroxy‐2‐phenylpropionic acid was carried out in acetonitrile solution containing 0.1 mol·L^?1 tetraethylammonium bromide. Influences of the nature of the electrodes, the working potential, the passed charge and the concentration of acetophenone on the electrocarboxylation were studied. After optimizing the synthetic parameters, the maximal isolated yield reached 73.0% on Mg‐stainless steel couple electrodes under potentiostatic electrolysis until 2.2 F·mol^?1 of charge was passed at 25 °C. The reduction of acetophenone was studied by cyclic voltammetry and the mechanism has been proposed on the basis of the results.     

四苯基卟啉钴催化有机化合物与二氧化碳的电羧化反应Ⅱ.

研究了α、β、γ、δ－四苯基卟啉钴（ＣｏＴＰＰ）存在下苄基氯、苯乙酮、二苯甲酮和萘等与ＣＯ＿２的电羧化反应，与无催化剂体系相比，ＣｏＴＰＰ可使这些有机化合物与ＣＯ＿２电羧化反应的过电位降低约８００～１０００ｍＶ，对反应有较高的催化活性．用ＵＶ，ＩＲ和ＧＣ－ＭＳ确认了电羧化产物，并探讨了ＣｏＴＰＰ催化反应机理．     

Efficient Fixation of Carbon Dioxide by Electrolysis Facile Synthesis of Useful Carboxylic Acids

Electrochemical fixation of atmospheric pressure of carbon dioxide to organic compounds is a useful and attractive method for synthesizing of various carboxylic acids. Electrochemical fixation of carbon dioxide, electrochemical carboxylation, organic halides, organic triflates, alkenes, aromatic compounds, and carbonyl compounds can readily occur in the presence of an atmospheric pressure of carbon dioxide to form the corresponding carboxylic acids with high yields, when a sacrificial anode such as magnesium or aluminum is used in the electrolysis. The electrochemical carboxylation of vinyl bromides was successfully applied for the synthesis of the precursor of nonsteroidal anti-inflammatory agents such as ibuprofen and naproxen. On the other hand, supercritical carbon dioxide （scCO2） has significant potential as an environmentally benign solvent in organic synthesis and it could be used both as a solvent and as a reagent in these electrochemical carboxylations by using a small amount of cosolvent.     

以镍为阴极由二氧化碳与芳香酮电合成α-羟基羧酸

室温下,在一室电解池中,以n-Bu4NBr-DMF作电解质、镍为阴极、铝为阳极,恒电流电解二氧化碳与芳香酮（苯乙酮、对二苯甲酮、6-甲氧基-2-萘乙酮、4-甲基苯乙酮和4-甲氧基苯乙酮）,可以得到相应的α-羟基羧酸（产率56%-90%）。实验结果显示,阴极材料、芳香族酮的结构以及电解条件（如电量、底物浓度、导电盐、溶剂和二氧化碳压力等）对目标产物的产率有很大影响;反应系统中质子剂（水）的存在将导致副产物频哪醇的生成。本文还根据循环伏安实验和合成实验结果简要地讨论了反应机理。     

Selective and Efficient Reduction of Carbon Dioxide to Carbon Monoxide on Oxide‐Derived Nanostructured Silver Electrocatalysts

In this work, the selective electrocatalytic reduction of carbon dioxide to carbon monoxide on oxide‐derived silver electrocatalysts is presented. By a simple synthesis technique, the overall high faradaic efficiency for CO production on the oxide‐derived Ag was shifted by more than 400 mV towards a lower overpotential compared to that of untreated Ag. Notably, the Ag resulting from Ag oxide is capable of electrochemically reducing CO₂ to CO with approximately 80 % catalytic selectivity at a moderate overpotential of 0.49 V, which is much higher than that (ca. 4 %) of untreated Ag under identical conditions. Electrokinetic studies show that the improved catalytic activity is ascribed to the enhanced stabilization of COOH^. intermediate. Furthermore, highly nanostructured Ag is likely able to create a high local pH near the catalyst surface, which may also facilitate the catalytic activity for the reduction of CO₂ with suppressed H₂ evolution.     

Methane Conversion to Higher Hydrocarbons in the Presence of Carbon Dioxide Using Dielectric-Barrier Discharge Plasmas

Experimental investigation has been conducted to convert methane into higher hydrocarbons in the presence of carbon dioxide within dielectric-barrier discharge (DBD) plasmas. The objectives of cofeed of carbon dioxide are to inhibit carbon deposit and to increase methane conversion. The products from this plasma methane conversion include: (1) syngas (H₂+CO), (2) gaseous hydrocarbons containing ethylene, acetylene, and propylene, (3) liquid hydrocarbons, (4) plasma-polymerized film, and (5) oxygenates. The selectivity of products is subject to the DBD plasma-reactive conditions and catalyst applied. The liquid hydrocarbons produced by this way are highly branched, which represents a better fuel production.     

Microfluidic Studies of Carbon Dioxide

Carbon dioxide (CO₂) sequestration, storage and recycling will greatly benefit from comprehensive studies of physical and chemical gas–liquid processes involving CO₂. Over the past five years, microfluidics emerged as a valuable tool in CO₂‐related research, due to superior mass and heat transfer, reduced axial dispersion, well‐defined gas–liquid interfacial areas and the ability to vary reagent concentrations in a high‐throughput manner. This Minireview highlights recent progress in microfluidic studies of CO₂‐related processes, including dissolution of CO₂ in physical solvents, CO₂ reactions, the utilization of CO₂ in materials science, and the use of supercritical CO₂ as a “green” solvent.     

Adsorption of Carbon Dioxide on Activated Carbon

The adsorption of CO2 on a raw activated carbon A and three modified activated carbon samples B, C, and D at temperatures ranging from 303 to 333 K and the thermodynamics of adsorption have been investigated using a vacuum adsorption apparatus in order to obtain more information about the effect of CO2 on removal of organic sulfur-containing compounds in industrial gases. The active ingredients impregnated in the carbon samples show significant influence on the adsorption for CO2 and its volumes adsorbed on modified carbon samples B, C, and D are all larger than that on the raw carbon sample A. On the other hand, the physical parameters such as surface area, pore volume, and micropore volume of carbon samples show no influence on the adsorbed amount of CO2. The Dubinin-Radushkevich (D-R) equation was the best model for fitting the adsorption data on carbon samples A and B, while the Preundlich equation was the best fit for the adsorption on carbon samples C and D. The isosteric heats of adsorption on carbon samples A, B, C, and D derived from the adsorption isotherms using the Clapeyron equation decreased slightly increasing surface loading. The heat of adsorption lay between 10.5 and 28.4 kJ/mol, with the carbon sample D having the highest value at all surface coverages that were studied. The observed entropy change associated with the adsorption for the carbon samples A, B, and C (above the surface coverage of 7 ml/g) was lower than the theoretical value for mobile adsorption. However, it was higher than the theoretical value for mobile adsorption but lower than the theoretical value for localized adsorption for carbon sample D.     

An Efficient and Novel Synthesis of Carbamate Esters from the Coupling of Amines, Halides and Carbon Dioxide in the Presence of Basic Resin

Organic carbamates exhibit unique physical, chemical and biological properties, accommodating variety of applications in pharmacology1 (drugs, prodrugs and drug intermediates), agriculture2 (pesticides, insecticides, fungicides, herbicides etc.) and as synthetic intermediates in chemical industry3. Their use as protection of amino groups in peptide synthesis4 and as linkers in combinatorial chemistry5 is also well known. Functionalization of amines as carbamates offers an attractive method for…     

Carbon Dioxide Capture and Use: Organic Synthesis Using Carbon Dioxide from Exhaust Gas

A carbon capture and use (CCU) strategy was applied to organic synthesis. Carbon dioxide (CO₂) captured directly from exhaust gas was used for organic transformations as efficiently as hyper‐pure CO₂ gas from a commercial source, even for highly air‐ and moisture‐sensitive reactions. The CO₂ capturing aqueous ethanolamine solution could be recycled continuously without any diminished reaction efficiency.     

二氧化碳参与的有机化学反应*

由于对日趋严重的温室效应的担忧,对廉价二氧化碳的固定和转化成为一个非常有吸引力的研究领域。本文主要介绍了二氧化碳参与的有机化学反应,包括与环氧化合物、胺类化合物、不饱和碳氢化合物以及醇类和烃类等化合物的反应。文章分别对这几类反应的发展历程、研究现状进行了总结,重点介绍了各反应所用到的催化剂体系及有关反应机理,并展望了该领域的研究前景。     

CO2气氛下负载型Cr2O3催化剂上乙苯脱氢制苯乙烯反应

 采用浸渍法制备了负载型Cr2O3/Al2O3和Cr2O3/SiO2催化剂,并考察了催化剂在CO2气氛下催化乙苯脱氢制苯乙烯反应的活性. 结果表明,Cr2O3/Al2O3的催化活性高于Cr2O3/SiO2. 这可能是由于Cr2O3在Al2O3载体表面的分散度大大高于在SiO2表面的分散度. 催化剂的催化活性与Cr2O3的负载量有关,在w(Cr2O3)=25%时,Cr2O3/Al2O3的催化活性最高. CO2气氛对乙苯脱氢反应有明显的促进作用; 在CO2气氛下,Cr6+物种可能是催化乙苯脱氢反应活性位的前驱体.     

含氧气氛下预硫化钙钛矿LaCoO3上的CO还原SO2反应

 对钙钛矿LaCoO3在含氧气氛下的预硫化过程进行了研究．结果表明，在一定含氧气氛下硫化后的LaCoO3催化剂，用于含氧气氛下CO还原SO2反应具有很高的活性．XRD物相分析结果表明，硫化后的LaCoO3仍保持钙钛矿物相结构，但同时出现新的硫化物La2O2S和氧化物Co3O4物相．通过对硫化前后的催化剂进行O2－TPD和SO2－TPD分析，认为CO还原SO2反应机理可能是在一定的温度下，在钙钛矿LaCoO3上发生CO氧化燃烧反应，在硫化物La2O2S上发生CO还原SO2反应，两者相互促进．     

由杂多钼酸盐前驱体制备的氧化钼催化剂催化CO_2存在下的异丁烷脱氢(英文)

Molybdenum based oxide catalysts Mo-H,Mo-Fe,Mo-Ce,and Mo-Sn were prepared by calcining H3PMo12O40,Fe1.5 PMo 12O40,Ce1.5PMo12O40,and Sn1.5 PMo12O40 heteropolyanion precursors at700℃,respectively.The prepared oxides have been characterized and tested for the dehydrogenation of isobutane(IB)to isobutene in the presence of CO2.The effects of temperature,time on stream,and CO2 /IB ratio were investigated.It was found that α-and-MoO3 phases were present in all catalysts.Catalytic tests showed that increasing the reaction temperature increased both the conversion and isobutene selectivity,whereas increasing the CO2 /IB molar ratio increased the conversion but decreased the selectivity for isobutene.Iron was found to be an effective additive element for the enhancement of catalytic activity compared with Ce and Sn.     

二氧化碳存在下甲烷氧化细菌催化甲烷生物合成甲醇

 在甲烷单加氧酶和脱氢酶系的作用下,甲烷氧化细菌Methylosinus trichosporium IMV 3011可以把甲烷氧化成二氧化碳. 在反应体系中充入一定比例的二氧化碳后,检测到了甲醇的积累. 混合气中CO2,CH4,O2和N2的体积比为2∶1∶1∶1时甲醇的积累量达到最大. 在超滤膜反应器中进行了连续反应,利用反应混合气产生的压力将生成的甲醇从反应体系中分离. 连续反应198 h后甲醇的积累量没有明显下降.     

二氧化碳催化加氢及其研究进展*

综述了二氧化碳热催化加氢的现状和研究进展,为进一步开展二氧化碳催化加氢的研究提供参考