烯烃与二氧化碳直接合成环碳酸酯的研究进展

二氧化碳(CO_2)是一种来源丰富、价廉易得的C1资源,将二氧化碳化学固定为环碳酸酯是最具工业应用前景的CO_2资源化利用途径之一。相比于环氧化物与CO_2反应制备环碳酸酯,以毒性小、价格低廉的烯烃为原料,通过环氧化、CO_2环加成反应一步制备环碳酸酯,由于反应路线简洁、原子经济性高,具有重要的工业应用价值。在此回顾了近年来烯烃与CO_2直接合成环碳酸酯的研究进展,着重介绍了不同种类的催化剂,主要包括离子液体、金属氧化物或盐、金属有机配合物、金属有机框架材料等催化剂,并对其未来发展方向进行了展望。     

低成本环状碳酸酯新工艺诞生

近日,南开大学的科研人员开发出了一种新型固体催化剂用于制备环状碳酸酯,这种高分子负载催化剂可做到一相反应、两相分离,利用二氧化碳与环氧化物加成反应合成环状碳酸酯,大大简化了工艺流程,产品无需经过分离、纯化过程,纯度就可达到99%以上,且生产成本大大降低。该新工艺的技术路线是:设计并合成非均相催化剂和亲二氧化碳的均相催化剂,用超临界二氧化碳作为溶剂,实现催化剂与产物的直接分离并循环使用。这一对二氧化碳温室气体的资源化利用技术具有广阔的应用前景。     

非异氰酸酯路线合成聚羟氨酯的研究

由非异氰酸酯路线合成聚氨酯,避免使用有毒、难运输和贮存的异氰酸酯,是聚氨酯的绿色合成路线,属于高分子合成化学的前沿课题。本文报道了一种由双环碳酸酯与二元胺加成聚合制备聚羟氨酯的新路线,其中双环碳酸酯是由含双环氧基团的环氧树脂与二氧化碳(CO 2)在双金属氰化络合物与季铵盐组成的二元催化剂催化下高效偶合反应得到。双环碳酸酯在季铵盐催化下与二元胺加成聚合,得到聚羟氨酯。由此提供了一条以环氧树脂、C O2和二元胺为原料合成聚羟氨酯的新途径。     

加压法合成碳酸丙烯酯工艺过程控制

介绍了碳酸丙烘酯的用途及合成方法，重点阐述了以四乙基溴化铵为催化剂环氧丙烷和二氧化碳在加压条件下合成碳酸烯酯的反应机理和工艺流程，从反应温度、压力、时间、CO2输送、精馏方式、催化剂回收等方面对生产工艺过程控制进行了探讨，总结出一种效率高、成本低、质量好的碳酸烯酯生产工艺条件。     

二甘醇双烯丙基碳酸酯的合成方法

本发明二甘醇双烯丙基碳酸酯的合成方法涉及从二氧化碳制备碳酸酯，在二甘醇双烯丙基碳酸酯的合成反应中以烷基胍类化合物为催化剂，具体步骤是：向高压反应釜内加入二甘醇、碳酸钠、和氯丙烯，其摩尔比为二甘醇：     

二氧化碳与环氧丙(乙)烷管式反应制取碳酸丙(乙)烯酯生产方法

<正>二氧化碳与环氧丙(乙)烷管式反应制取碳酸丙(乙)烯酯生产方法 ,催化剂与环氧丙(乙)烷混合液、分散于循环碳酸丙(乙)烯酯中的二氧化碳并流进入管式碳酸丙(乙)烯酯合成反应器(3),边流动、边混合、边反应;通过管式碳酸丙(乙)烯酯合成反应器(3)外设夹套取出反应热;调整管式碳酸丙(乙)烯酯合成反应器(3)不同管段内冷却介质量获得合适的反     

超临界二氧化碳中合成环碳酸酯的催化剂研究进展

超临界二氧化碳(sc CO2)是一种环境友好型溶剂,它作为传统有机溶剂的替代品已被广泛应用于绿色化学过程的开发。其中,环氧化合物在超临界二氧化碳中制备环碳酸酯是实现二氧化碳高附加值转化的有效途径之一。本文回顾了近年来在超临界二氧化碳中合成环碳酸酯的研究进展,着重介绍了不同种类的催化剂,包括金属配合物、季盐、二元催化体系、离子液体、金属氧化物、有机小分子及其他类型催化剂在该反应体系中的应用,突出了超临界二氧化碳既作为溶剂,又作为反应物的双重优势。从经济和环境角度考虑,离子液体或季盐等有机催化剂具有更好的工业化应用前景。同时,指出了高效和绿色催化体系设计和创制是该研究领域的关键。     

由二氧化碳和苯酚一步合成水杨酸苯酯的方法

<正>本发明涉及一种由二氧化碳和苯酚一步合成水杨酸苯酯的方法,属于水杨酸苯酯合成技术领域。该方法以二氧化碳和苯酚为原料,在一定的二氧化碳压力和温度下,采用催化剂、助剂,直接催化合成水杨酸苯酯。本发明以二氧化碳、苯酚为原料一步催化合成水杨酸苯酯,其工艺路线简单,原料易得,成本低廉,避免了腐蚀性强和毒性大的原料及催化剂的使用;以二氧化碳作为反应物,实现二氧化碳化学利     

KI／PEG体系催化合成烷撑碳酸酯

以ＫＩ／ＰＥＧ络合物作催化剂，研究了二氧化碳与环氧乙烷及环氧丙烷合成烷撑碳酸酯的反应性能，对反应温度，压力及催化剂浓度等影响因素进行了考察，通过对第三组分作用的深入研究，制得一种高活性，高选择性的络合催化剂。     

碘化铯催化二氧化碳与甘油合成甘油碳酸酯

以不同碱金属(铵)卤化物为催化剂,考察了其在二氧化碳与甘油合成甘油碳酸酯反应中的活性。采用环氧丙烷为溶剂及耦合剂,极大提高了反应的转化率。实验结果发现碘化物具有较好的催化活性。以碘化铯为催化剂,考察了反应温度、反应时间、反应压力、反应物摩尔比和催化剂用量对反应结果的影响。在最佳反应条件下(环氧丙烷0.3 mol,甘油0.1 mol,反应温度120℃,反应时间1.5 h,反应压力3.0 MPa,催化剂用量0.15 g),甘油的转化率为86.5%,甘油碳酸酯的产率为81.6%。     

均相体系中酸碱协同催化二氧化碳与环氧化物的环加成反应

基于“可持续发展”和“绿色化学”的概念,近年来CO₂的捕获、储存及资源化利用在工业上和学术上一直备受关注。通过具有100%原子经济性特点的CO₂与环氧化物环加成反应合成五元环状碳酸酯是最有前景的方法之一。基于均相催化剂的设计思想与方法,以CO₂和环氧化物的活化本质出发,从催化剂结构的角度综述了均相体系中酸碱协同催化CO₂与环氧化物环加成反应合成环状碳酸酯的研究进展,包括简单二元催化体系、功能型一元催化体系和金属配合物催化体系等。     

Repeated use of molten carbonate catalysts for gasification of carbonaceous materials by carbon dioxide

Reactions of carbonaceous materials (activated carbon, graphite, and lignin) with carbon dioxide were carried out at 973 K using alkali metal carbonates (m.p. 891～1164 K) and eutectic mixtures of these compounds (m.p. 669～787 K) as catalysts. The reaction occurred when the carbonate catalysts were physically mixed with carbonaceous materials and the melting points of the catalysts were lower than the reaction temperature. However, the reaction did not proceed with physically mixed catalysts when the melting points of the catalysts were higher than the reaction temperature. Repeated use of the molten catalyst was also studied to investigate the possibility of continuous gasification of carbonaceous materials. After the activated carbon (or lignin) was consumed in a batch reactor, the same amount was added in the reactor containing the catalyst and the reaction started again. It was found that the eutectic molten catalyst could be reused without any loss of its catalytic activity by repeating this operation.     

Mechanisms of the alkali metal catalysed gasification of carbon

The catalytic effects of alkali metal salts in the gasification of carbonaceous materials by oxygen, steam and carbon dioxide are described. The most effective catalysts are generally the carbonates, oxides and hydroxides; other active salts tend to convert to these species under gasification conditions. Current theories of the mechanism of this type of catalysis are reviewed. Thermodynamic considerations, the results of thermal analysis and the magnitude of kinetic isotope effects suggest that cyclic sequences of elementary reactions are responsible for the catalytic phenomena.     

碳纳米管、碳化钨在直接法合成过氧化氢中的应用

选用新型纳米材料——碳纳米管（CNTs）作为催化剂载体,用沉积沉淀法制备负载型钯-铂合金催化剂。同时选用过渡金属碳化物材料（碳化钨）为催化剂,其具有类似于Pt的表面电子结构,有望替代贵金属催化剂。探讨了Pd-Pt/CNTs及碳化钨在氢氧直接合成过氧化氢反应中的催化性能。     

Direct synthesis of dimethyl carbonate from methanol and carbon dioxide over transition metal oxide/Ce<Subscript>0.6</Subscript>Zr<Subscript>0.4</Subscript>O<Subscript>2</Subscript> catalysts: Effect of acidity and basicity of the catalysts

Ce _X Zr_1−X O₂ catalysts with different cerium content (X) (X=0, 0.2, 0.4, 0.5, 0.6, 0.8, and 1.0) were prepared by a sol-gel method. Among these catalysts, Ce_0.6Zr_0.4O₂ showed the best catalytic performance in the direct synthesis of dimethyl carbonate from methanol and carbon dioxide. To see the effect of acidity and basicity of transition metal oxide/Ce_0.6Zr_0.4O₂ catalysts on the catalytic performance in the direct synthesis of dimethyl carbonate, MO/Ce_0.6Zr_0.4O₂ (MO=Ga₂O₃, La₂O₃, Ni₂O₃, Fe₂O₃, Y₂O₃, Co₃O₄, and Al₂O₃) catalysts were prepared by an incipient wetness impregnation method. NH₃-TPD and CO₂-TPD experiments were carried out to measure acidity and basicity of the supported catalysts, respectively. Experimental results revealed that both acidity and basicity of the catalysts played a key role in determining the catalytic performance in the direct synthesis of dimethyl carbonate from methanol and carbon dioxide. The amount of dimethyl carbonate produced over MO/Ce_0.6Zr_0.4O₂ catalysts increased with increasing both acidity and basicity of the catalysts. Among the catalysts tested, Ga₂O₃/Ce_0.6Zr_0.4O₂, which had the largest acidity and basicity, exhibited the best catalytic performance in the direct synthesis of dimethyl carbonate from methanol and carbon dioxide.     

Kinetics of the reaction of propylene oxide with carbon dioxide in the presence of tetrasubstituted ammonium and phosphonium halogenides

Reactions of alkylene oxides with carbon dioxide underlie the industrial technology of ethylene- and propylene carbonates. Looking for new catalytic systems for these processes remains of interest due to the possibility of creating a new energy-saving process for the production of ethylene and propylene glycols. This work is aimed at comparing the catalytic activity of halogenides in the reaction of propylene oxide (PO) and carbon dioxide in the presence of tetrasubstituted ammonium and phosphonium halogenides, and evaluating the feasibility of using them in designing industrial technologies for the production of alkylene carbonates and glycols as active catalytic systems. Triphenylphosphine halogenides have been shown to possess high catalytic activity as compared to triethanolamine-based analogs. In terms of efficiency, triphenylphosphonium bromides are as good as the familiar catalysts based on potassium iodide. The high activity of these catalysts in the reaction for propylene carbonate (PC) production and their good solubility in the reaction medium allow us to propose them for the development of industrial technology for the subsequent production of alkyl carbonates and alkylene glycols.     

二氧化碳合成碳酸二甲酯催化剂的研究进展

碳酸二甲酯是一种用途广泛的环境友好有机介成中间体,利用CO2合成碳酸二甲酯能有效利用C02资源,在环境保护和绿色合成化学方面具有重要的意义.综述了利用CO2合成碳酸二甲酯有机金属催化剂、氧化物催化剂、碱催化剂、负载型金属催化剂、醋酸盐催化剂及催化反应机理的研究进展,并展望了未来的发展方向.     

分子筛在双功能催化剂中催化CO/CO2加氢研究进展

双功能催化剂可将CO/CO_2加氢直接合成低碳烯烃、芳烃和汽油等,具有工艺流程短、能耗低的优势。双功能催化剂由金属氧化物和分子筛两部分组成,分子筛特定的腔体结构、酸性质及与金属氧化物的结合方式等均可显著影响其催化性能。该文综述了近年来分子筛在双功能催化剂中用于CO/CO_2加氢反应的研究进展,简述了分子筛的类型、酸性质、形貌及颗粒尺寸、金属改性、分子筛与金属氧化物的结合方式等对双功能催化剂催化性能的影响规律,展望了双功能催化剂中分子筛的发展趋势。     

The catalytic steam gasification of one Australian and three Japanese coals using potassium and sodium carbonates

The catalytic steam gasification of four different coals using potassium and sodium carbonates as catalysts was carried out in a semi-flow type fixed-bed reactor. The coal was gasified with or without the catalyst under a steam—argon atmosphere at a heating rate of 50°C/s at 700–800°C. The catalytic activity of carbonates for gasification was remarkable for Japanese high-volatile coals (Miike and Takashima coals), and moderate for Australian medium-volatile coal (New Lithgow coal); however, the carbonates had little effect on gasification of Japanese lignite (Taiheiyo coal). It is assumed that Miike and Takashima coals soften and melt during the heating process to make the contact between char and catalyst better. New Lithgow and Taiheiyo coals do not have this property. Gasification was promoted significantly at lower temperatures when the catalyst was used. In both catalyzed and uncatalyzed runs the main products were hydrogen and carbon dioxide; the reaction temperature did not affect the composition of the gases much. A water—gas shift reaction occurred during gasification resulting in a large amount of carbon dioxide under a large excess of steam flow.     

Direct synthesis of dimethyl carbonate from methanol and carbon dioxide over Ga2O3-CeO2-ZrO2 catalysts prepared by a single-step sol-gel method: Effect of acidity and basicity of the catalysts

XGa₂O₃-CeO₂-ZrO₂ (X=0, 1, 3, 5, 7, and 9) catalysts were prepared by a single-step sol-gel method with a variation of Ga₂O₃ content (X, wt%) for use in the direct synthesis of dimethyl carbonate from methanol and carbon dioxide. The ratio of cerium oxide:zirconium oxide in the XGa₂O₃-CeO₂-ZrO₂ catalysts was fixed to be Ce_0.6Zr_0.4O₂. Effect of acidity and basicity of XGa₂O₃-CeO₂-ZrO₂ on the catalytic performance in the direct synthesis of dimethyl carbonate from methanol and carbon dioxide was investigated using NH₃-TPD and CO₂-TPD experiments, respectively. Experimental results revealed that both acidity and basicity of the catalysts played important roles in determining the catalytic performance in the reaction. The amount of dimethyl carbonate increased with increasing both acidity and basicity of the catalyst. Among the catalysts tested, 3Ga₂O₃-CeO₂-ZrO₂, which retained the largest acidity and basicity, exhibited the best catalytic performance in the direct synthesis of dimethyl carbonate from methanol and carbon dioxide.