Cobalt-zeolite catalysts for the synthesis of hydrocarbons from CO and H2

Catalysts prepared by mechanical mixing of high-silica zeolite ZSM-5 with cobalt oxide Co₃O₄, basic cobaltous carbonate, and cobaltous carbonate were studied. The nature of the cobalt compound introduced into the mixture affects the catalytic and physicochemical properties of the catalyst. The presence of Co₃O₄ in the sample (introduced as oxide or obtained by thermal decomposition of the carbonate) is favorable to the formation of aromatic compounds from CO and H₂. The use of cobaltous carbonates for the preparation of catalysts results in development of the porous structure of the catalyst. During preparation of samples, the mechanical treatment partially destroys the zeolite framework of the support.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1070–1073, June, 1995.     

Reaction of CO2 and H2 in the presence of Co and Ni catalysts

The activity and selectivity of 10 % Co/support and 10 % Ni/support catalysts (where the support is A1₂O₃, SiO₂, C) in the synthesis of hydrocarbons from CO₂ and H₂ were studied. The extent of conversion of the starting mixture and the yield of methane were shown to depend on the composition of the catalytic system. Cobalt catalysts with various types of carbons as supports are the most active. They permit the synthesis of methane in yields up to 70 % of the theoretical value.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 482–484, March, 1993.     

Metallosilicates as supports of Co catalysts for the synthesis of liquid hydrocarbons from CO and H2

The effect of the nature of the silicate support on the activity and selectivity of 10%. Co/M silicate catalysts (where M=Cu, Zn, Ce, Ti, Hf, La, Al, Zr, Co, Mg) in the synthesis of hydrocarbons from CO and H₂ has been established. Co and Zr catalysts have been shown to provide the highest catalytic efficiency. The yield of liquid hydrocarbons in their presence exceeds 120 g m^–3.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 480–482, March, 1993.     

Synthesis of hydrocarbons and alcohols from CO and H2 in the presence of CO-Rh catalysts

Catalysts of 4.5% Co- 0.1% Rh- 5:10% Cu/TiO ₂ display high activity in the synthesis from CO and H₂ of a mixture of hydrocarbons and alcohols at 250–300°C and pressures of 0.1–6.0 MPa; these catalysts are more selective than traditional Co catalysts with respect to alcohol formation.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1707–1709, August, 1990.     

Investigation of a Co-MgO-ZSM catalyst by temperature-programmed reduction,temperature-programmed desorption,and IR spectroscopy

The 32% Co-3% MgO-ZSM (SiO₂/Al₂O₃=38) system has been studied by means of temperature-programmed reduction, temperature-programmed desorption, and IR spectroscopy. The data from temperature-programmed reduction show that cobalt exists on the surface of the catalyst in the form of Co²⁺, CoO, Co₃O₄, and CoO·MgO solid solutions. Reduction of the sample results in the formation of a very inhomogeneous surface with four groups of sites.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow. J. Heyrovsky Institute of Physical Chemistry and Electrochemistry, Czechoslovak Academy of Sciences, Prague. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 55–59, January, 1992.     

Synthesis of hydrocarbons from CO and H2 on SiO2 supported iron-cobalt clusters

Bimetallic catalysts (Fe+Co)/SiO₂ were prepared by impregnation of SiO₂ with solutions of carbonyl clusters [FeCo₃(CO)₁₂][(C₂H₅)₄N], [Fe₃Co(CO)₁₃][(C₂H₅)₄N], HFeCo₃(CO)₁₂, [Fe₅CoC(CO)₁₆][(C₂H₅)₄N], and Co₂(CO)₈, Fe(CO)₅. At 20 °C, no reaction occurs between the compounds supported and the surface of the support. The stability of the supported clusters to thermodecarboxylation in a hydrogen atmosphere depends on their composition and is the highest for the catalyst [FeCo₃(CO)₁₂]^–/SiO₂. The catalytic properties of supported clusters in CO hydrogenation are mostly determined by the preactivation technique. The properties of Fe-Co catalysts which were pretreated at high temperatures, are in general similar to those of standard metal catalysts. Product distribution for the same samples prepared without preactivation does not fit the Schulz-Flory equation. The catalyst HFeCo₃(CO)₁₂/SiO₂ favors the formation ofC ₁–C₁₁ hydrocarbons in the temperature range of 468–473 K; the catalyst [Fe₃Co(CO)₁₃]^–/SiO₂ gives ethylene in the temperature range of 453–473 K.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1079–1085, June, 1993.     

Adsorption of CO on Ru and Pt blacks and catalysts and the possibility of its utilization for the determination of the ruthenium-free surface

Electrochemical voltammetric curves on Ru and Pt blacks of a different surface area were measured in potential intervals 0.05–1.05 V in pure 0.5 M H₂SO₄ and after CO adsorption. It was proved that after the CO adsorption, the outset of ruthenium oxidation is shifted by about 150 mV towards the positive potentials, e.g. to the region of oxidation of adsorbed CO. This fact made possible the determination of a double-layer charging current of Ru electrodes and, subsequently, also the determination of the amount of adsorbed hydrogen on the Ru surface. An evaluation of the amount of CO and hydrogen adsorption showed that the ratio of adsorbed CO:H on the Pt surface was about 1:1, while on Ru electrodes this ratio was around twice as large. The amount of hydrogen adsorbed on Ru blacks depends on the preliminary preparation of the electrodes. The CO adsorption could also be employed in the determination of a charging current of electrode double-layers during voltammetric oxidation of adsorbed hydrogen on ruthenium supported on Al₂O₃, SiO₂, or TiO₂ carriers. However, a similar determination of hydrogen adsorbed on the tin-modified Ru catalysts is not very reliable.     

还原气氛对钴锆共沉淀催化剂结构和费托合成反应性能的影响

采用程序升温还原、氮吸附、原位X射线衍射、扫描电镜和透射电镜等方法研究了不同还原气氛对钴锆共沉淀催化剂结构的影响,并考察了催化剂上费托合成反应的性能.结果表明,H2还原对催化剂的破坏程度较小,活性相主要是面心立方钴;CO还原导致催化剂发生积碳,催化剂中出现面心立方钴和六方钴的混晶;合成气还原使催化剂烧结严重,单质钴以面心立方和六方两种晶相存在.费托合成反应结果表明,CO还原后催化剂没有催化性能,H2还原与合成气还原后催化剂的催化活性相差不大,但前者CH4选择性较低.     

碱金属助剂对CoCu/TiO2催化剂上二氧化碳加氢合成长链烃的影响

大气中CO2浓度增加导致的温室效应以及化石燃料的匮乏正日益受到世界范围的关注. 由于CO2较强的惰性以及较高 C-C 偶联能垒, 迄今为止大部分研究都集中在CO2催化加氢制备各种 C1 化学品 (如 CH4, CH3OH, CO 等), 鲜有研究关注合成液态燃料 (C5+碳氢化合物). 目前,CO2加氢直接合成烃类主要通过CO2基费托合成反应 (CO2-FTS) 实现, 即先通过逆水煤气变换反应 (RWGS) 将CO2还原成 CO, 随后 CO 通过传统费托反应 (FTS) 加氢生成烃类化合物. 在两种工业化FTS 催化剂 (Fe 和 Co 基催化剂) 中, 钴基催化剂具有更高的反应活性和链增长能力, 以及较高的机械强度和稳定性. 然而,由于CO2的惰性, 造成催化剂表面物种的加氢程度更高, 使得甲烷更容易生成. 因而, 高反应活性、高选择性催化剂的开发是实现该过程的关键.本文采用沉积沉淀法制备了一系列双金属 CoCu/TiO2催化剂, 再通过初湿浸渍法对其进行碱金属助剂 (Li, Na, K, Rb和 Cs) 改性, 并用多种表征手段系统研究了碱金属助剂对催化剂物化性质及其催化CO2加氢制备长链烃反应的影响. 结果表明, 碱金属的加入对催化剂织构性质影响不大, 它们在催化剂表面发生富集, 且富集程度随碱金属原子序数的增加而降低. 另外, 碱金属的加入增强了CO2的吸附, 其中, Na 改性的 CoCu/TiO2催化剂的碱性最强; 同时还降低了 H2的脱附量,尤以 K, Rb 和 Cs 改性的催化剂为甚.在 250 oC, 5 MPa, 空速 3000 mL·gcat-1·h-1和 H2/CO2= 3 的反应条件下, 对不同碱金属助剂改性的催化剂进行评价. 结果表明, 不加助剂的 CoCu/TiO2催化剂上CO2转化率高达 23.1%, 但产物主要是 CH4, 此时CO2在 Co 活性中心上直接发生甲烷化反应; 碱金属助剂的引入显著抑制了 CH4的生成, 提高了长链烃的选择性, 但同时也降低了CO2转化率, 并且随着碱金属原子序数增大呈现先下降后上升的趋势, 表明合适的碱性强度可以更好地改性催化剂性能. 其中, Na 助剂改性的CoCu/TiO2催化剂的碱性最强, 且 H2的脱附量降低幅度较小, 因此, 该催化剂具有最高的 C5+烃类收率, 达到 5.4%; 同时CO2转化率为 18.4%, 烃类产物中 C5+烃类选择性为 42.1%. Na 助剂改性的 CoCu/TiO2催化剂还展现了良好的催化稳定性,反应 200 h 后,CO2转化率和 C5+选择性分别保持 18% 和 40%. 基于碱金属助剂对催化剂物化性质与反应性能的调变规律,可进一步指导CO2加氢直接合成长链碳催化剂的设计与合成.     

Zr助剂对Co/AC催化剂催化费-托合成反应性能的影响

 采用CO加氢反应、X射线衍射(XRD)、透射电镜(TEM)、程序升温还原(TPR)和程序升温表面反应(TPSR)等技术考察了Zr助剂对Co/AC催化剂催化费-托合成反应性能的影响. 结果表明,还原、钝化后的Co-Zr/AC催化剂的XRD谱上只有较弱的CoO特征衍射峰; 反应50 h后,催化剂中Co主要以fcc晶相存在,同时还含有少量hcp晶相的Co; 加入Zr助剂后Co晶相衍射峰明显减弱. TEM结果表明, 15%Co/AC中Co的平均粒径为20 nm,加入Zr后Co粒径变小,15%Co-6%Zr/AC中Co的粒径为10 nm. CO加氢、XRD和TEM结果表明,加入Zr助剂可以提高活性组分Co的分散度,同时催化剂的活性随分散度的增大而增大. TPR和TPSR实验结果证实了上述结论.     

Ru助剂对Co/SiO2催化剂费托合成反应性能的影响

 考察了 Ru 助剂 (0.17%?9.96%) 对 Co/SiO2 催化剂结构及其费托合成反应性能的影响. 结果表明, Ru 助剂可降低 Co/SiO2 催化剂的还原温度, 从而提高其还原度. 光电子能谱和扩展 X 吸收射线精细结构研究表明, 即使 Ru 含量高达 9.96%, 在 Co/SiO2 催化剂焙烧过程中也未观察到 Ru 物种与 Co 物种作用形成的化合物. 还原后催化剂中 Ru 趋向于与 Co 物种紧密接触且分散在催化剂表面. H2 程序升温脱附结果表明, 随着 Ru 含量的增加, 位于反应温度附近的 H2 脱附峰面积增加, 即此时催化剂吸附 H2 能力提高, 因此反应活性单调增加, 但存在最佳 Ru 含量, 此时 C5+选择性最高.     

Synthesis of mixtures of aromatic and aliphatic hydrocarbons from CO and H2 over Fe catalysts

It was determined that 8.2% Fe-1–4.5% K/Al ₂ O ₃ catalysts are active in the synthesis of C ₁ -C ₆ aliphatic and C ₆ -C ₈ aromatic hydrocarbons (AH) from mixtures of CO:H ₂ =1:2–2:1. The AH content in the liquid reaction products is 90%. A discussion of the synthesis schemes for AH is presented.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 117334. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 3, pp. 546–551, March, 1992.     

Synthesis of hydrocarbons from CO and H2 using Co-mixed-oxide catalysts

Conclusions The use of binary carriers made of oxides of silicon and Mg, Be, Zr, and Mn for Co catalysts for synthesis of liquid hydrocarbons from CO and H₂ leads to an increase in their activity and selectivity in comparison with individual oxides, and also to an increase in the catalyzate of the isoparaffin content and that of hydrocarbons of the C₁₁-C₁₈ fraction.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimcheskaya, No. 11, pp. 2474–2477, November, 1988.The authors express their gratitude to A. A. Vedenyapin for performing differential thermal analysis.     

Synthesis of hydrocarbons from CO and H2 on supported nickel-palladium catalysts

The use of an Ni-Pd/Al₂O₃ catalyst in the synthesis of C₁-C₄ hydrocarbons from CO and H₂ permits us to increase the selectivity and total yield of these products by a factor of 1.5–2.0 relative to the corresponding nickel and palladium catalysts. The optimal temperatures and CO/H₂ ratios for obtaining hydrocarbons were determined. A structure was proposed for the active sites of the bimetallic catalyst.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1689–1691, July, 1991.     

Synthesis of Pd catalysts based on a nonbornene−CO copolymer and their properties in the carbomethoxylation of propylene

It was found that carboxylation of norbornene (nbn) in the presence of the PdCl₂−PPh₃−HCl catalytic system is accompanied by alternating copolymerization ofnbn with carbon monoxide to form norbornanecarboxylic acid (yield ∼20%) and anbn-CO copolymer (yield ∼80%,M _w=1600,M _w/M _n=1.6). The Pd^II salt of poly(norbornaneketone)carboxylic acid is a highly active catalyst for the carbomethoxylation of propylene. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 368–370, February, 1998.     

Synthesis of hydrocarbons from CO and H2 on promoted cobalt-carbon fiber catalysts

Conclusions Cobalt catalysts with carbon fiber supports promoted by MgO, Al₂O₃, and ZrO₂ are active in the synthesis of C₁-C₄ hydrocarbons from CO and H₂.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2634–2636, November, 1988.     

Cu-Co-Fe oxide catalysts supported on carbon nanotubes for the oxidation of CO

The catalytic activity and adsorption characteristics of the surface of catalysts in the form of carbon nanotubes produced on nickel and cobalt oxides with the Cu-Co-Fe oxide system as supported active phase were studied. At carbon nanotubes produced on nickel oxide with (10 + 10) wt.% of the catalytically active phase total conversion of CO to CO₂ is realized at 47 °C. This sample has high specific surface area and a large volume of mesopores. It was shown that the increase in catalytic activity correlates with the increase in the amount of the α₂ form of CO₂. __________ Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 42, No. 4, pp. 222–226, July–August, 2006.     

CO oxidation over Co3O4/SiO2 catalysts: Effects of porous structure of silica and catalyst calcination temperature

The catalytic performances of Co3O4/SiO2 catalysts prepared by incipient wetness impregnation for CO oxidation were investigated using three kinds of silica as carriers with different pore sizes of 7.7, 14.0 and 27.0 nm. The effects of calcination temperature on the catalyst surface and micro structure properties as well as catalytic performance for the oxidation of carbon monoxide were also studied. All catalysts were characterized by N2 adsorption-desorption, XRD, XPS, FTIR, H2-TPR and O2-TPD. It was found that the properties and crystal size of cobalt-containing species strongly depended on the pore size of silica carrier. While the silica pore size increased from 7.7 to 27.0 nm, the Co3O4 crystal size increased from 8.5 to 13.5 nm. Moreover, it was demonstrated that if the spinel crystal structure of Co3O4 was obtained at a calcination temperature as low as 150 ℃, the catalyst sample would have a high Co3O4 surface dispersion and a increase of surface active species, and thus exhibit a high activity for the oxidation of carbon monoxide.