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Enhancing the aromatic selectivity of cyclohexane aromatization by CO2 coupling

《化学科学与工程前沿(英文)》 2023年 第17卷 第11期   页码 1801-1808 doi: 10.1007/s11705-023-2325-9

摘要: Improving the aromatic selectivity in the alkane aromatization process is of great importance for its practical utilization but challenge to make because the high H/C ratio of alkanes would lead to a serious hydrogen transfer process and a large amount of light alkanes. Herein, CO2 is introduced into the cyclohexane conversion process on the HZSM-5 zeolite, which can improve the aromatic selectivity. By optimizing the reaction conditions, an improved aromatic (benzene, toluene, xylene, and C9+) selectivity of 48.2% can be obtained at the conditions of 2.7 MPa (CO2), 450 °C, and 1.7 h−1, which is better than that without CO2 (aromatic selectivity = 43.2%). In situ transmission Fourier transform infrared spectroscopy spectra illustrate that many oxygenated chemical intermediates (e.g., carboxylic acid, anhydride, unsaturated aldehydes/ketones or ketene) would be formed during the cyclohexane conversion process in the presence of CO2. 13C isotope labeling experimental results demonstrate that CO2 can enter into the aromatics through the formation of oxygenated chemical intermediates and thereby improve the aromatic selectivity. This study may open a green, economic, and promising way to improve the aromatic selectivity for alkane aromatization process.

关键词: aromatics     carbon dioxide     aromatization     coupling reaction     ZSM-5 zeolite    

Studies on QSAR of metalloporphyrin catalysts in the oxidation of cyclohexane to adipic acid

CHEN Yixia, SHE Yuanbin, XU Jing, LI Yan

《化学科学与工程前沿(英文)》 2007年 第1卷 第2期   页码 155-161 doi: 10.1007/s11705-007-0029-1

摘要: The catalysis of chloridized metalloporphyrins in the oxidation of cyclohexane to adipic acid was systematically investigated. The turnover numbers (TON) data of 19 catalysts were obtained experimentally under optimal reaction conditions, and 2.4?10 TON for T(-Cl)PP-MnCl catalyst at 2.0?10 mol/L of dosage was reached under the conditions of dioxygen pressure of 2.5 MPa at 150?C for 4 h. This was the best result reported for this reaction up to now. The QSAR models for each concerned metalloporphyrin were established, where the catalytic activity was significantly correlated with the (the energy level of the lowest unoccupied molecule orbit) and L (the bond length between metal-nitrogen atoms). Using the QSAR models, four new metalloporphyrins with substituted nitro group were designed, and their catalytic activities were predicted. The experimental TON data of newly designed porphyrins were in good agreement with the predicted ones, and the square of their correlation coefficient was more than 0.958. The above results demonstrated that the proposed structure-activity relationship model could be applied to design some new metalloporphyrin catalysts, and to predict their catalytic activity in cyclohexane oxidation.

关键词: cyclohexane     concerned metalloporphyrin     structure-activity relationship     metal-nitrogen     oxidation    

Highly selective catalytic hydrodeoxygenation of guaiacol to cyclohexane over Pt/TiO

Zhong HE,Xianqin WANG

《化学科学与工程前沿(英文)》 2014年 第8卷 第3期   页码 369-377 doi: 10.1007/s11705-014-1435-9

摘要: Catalysts Pt/TiO and NiMo/Al O are highly active and selective for the hydrodeoxygenation of guaiacol in a fixed bed reactor at 300 °C and 7.1 MPa, leading to the hydrogenation of aromatic ring, followed by demethylation and dehydroxylation to produce cyclohexane. For a complete hydrodeoxygenation of guaiacol, metal sites and acid sites are required. NiMo/Al O and Pt/Al O are more active and selective for cyclohexane formation as compared with Pt/TiO at 285 °C and 4 MPa. However, Pt/TiO is stable while the other two catalysts deactivate due to the nature and amount of coke formation during the reaction.

关键词: Pt/TiO2     NiMo/Al2O3     Pt/Al2O3     bio-oil     hydrodeoxygenation     guaiacol     cyclohexane    

Conversion of phenol to cyclohexane in the aqueous phase over Ni/zeolite bi-functional catalysts

Jimei Zhang, Fuping Tian, Junwen Chen, Yanchun Shi, Hongbin Cao, Pengge Ning, Shanshan Sun, Yongbing Xie

《化学科学与工程前沿(英文)》 2021年 第15卷 第2期   页码 288-298 doi: 10.1007/s11705-020-1932-y

摘要: A series of Ni/HZSM-5 and Ni/HIM-5 bi-functional catalysts were synthesized and applied to the aqueous-phase hydrodeoxygenation (HDO) of phenol. The Ni dispersibility and particle sizes were shown to be directly related to the porosity and crystal sizes of the parent zeolites, which further influenced the catalytic performances. The large pores and small crystal sizes of the parent zeolites were beneficial for dispersing Ni and forming small Ni particles, and the corresponding Ni/zeolite catalyst exhibited a higher phenol conversion and selectivity towards hydrocarbons. Importantly, the Ni/HIM-5 bi-functional catalyst exhibited a high activity (98.3%) and high selectivity for hydrocarbons (98.8%) when heated at 220°C for 1 h and is thus a new potential catalyst for the HDO of phenolics to form hydrocarbons in the aqueous phase.

关键词: aqueous-phase hydrodeoxygenation     phenol     hydrocarbons     Ni/HIM-5     bi-functional catalyst    

Advances and perspectives in catalysts for liquid-phase oxidation of cyclohexane

Hui LI, Yuanbin SHE, Tao WANG

《化学科学与工程前沿(英文)》 2012年 第6卷 第3期   页码 356-368 doi: 10.1007/s11705-012-0903-3

摘要: The latest progress and developments in catalysts for the oxidation of cyclohexane are reviewed. Catalytic systems for the oxidation of cyclohexane including metal supported, metal oxides, molecular sieves, metal substituted polyoxometalates, photocatalysts, organocatalysts, Gif systems, metal-organic catalysts and metalloporphyrins are discussed with a particular emphasis on metalloporphyrin catalytic systems. The advantages and disadvantages of these methods are summarized and analyzed. Finally, the development trends in the oxidation technology of cyclohexane are examined.

关键词: cyclohexane     liquid-phase oxidation     catalysis    

One-step synthesis of

Kuiyi YOU, Fangfang ZHAO, Xueyan LONG, Pingle LIU, Qiuhong AI, Hean LUO

《化学科学与工程前沿(英文)》 2012年 第6卷 第4期   页码 389-394 doi: 10.1007/s11705-012-1218-0

摘要: A simple and efficient approach for the synthesis of -caprolactam via the liquid phase nitrosation of cyclohexane and nitrosyl sulfuric acid in the presence of concentrated sulfuric acid has been developed. A series of novel AlVPO composites were prepared by an impregnation method and the composites were then employed to catalyze the nitrosation reaction of cyclohexane and nitrosyl sulfuric acid. Compared to the reaction using fuming sulfuric acid, the selectivity for the desired product was significantly improved using this one-step catalytic process. This method affords a shortcut to prepare -caprolactam and its analogs from cyclohexane.

关键词: cyclohexane     ?-caprolactam     AlVPO composite catalysts     one-step synthesis     concentrated sulfuric acid    

新型苯加氢反应器的研究

A.M.Anter,程振民,肖琼,胡劲松,袁渭康

《中国工程科学》 2000年 第2卷 第6期   页码 59-63

摘要:

文章提出了依靠相变蒸发吸收反应热,同时解决移热和加速反应等问题的新型化学反应器并开展了实验研究。实验在加压下进行,催化剂床层高度为1.0m,反应器内径为0.02m,苯加氢生成环已烷为研究体系,实验中采用气液并流向上流动的方式通过催化剂床层。在操作条件:ρ=0.5~3.0MPa、θ=150℃、液体空速=1.1~6.9h-1、氢油体积比=300~1910下,苯的转化率及环已烷的收率均可达到99.9%以上。为了防止反应器内发生飞温,实验采用苯与环已烷的混合物作为原料,其中苯的质量分数为15%~25%。随着反应物料不断进入反应器,液相物料吸收反应放出的热量而蒸发,因此在适当的操作条件下床层内可同时存在液相反应区、气液两相区和气相反应区。

关键词: 相变反应器         加氢     环已烷    

co-precipitation synthesis of mesoporous Co3O4–CeO2 composite oxides for highly selective catalytic oxidation of cyclohexane

《化学科学与工程前沿(英文)》 2022年 第16卷 第8期   页码 1211-1223 doi: 10.1007/s11705-022-2145-3

摘要: The one-step highly selective oxidation of cyclohexane into cyclohexanone and cyclohexanol as the essential intermediates of nylon-6 and nylon-66 is considerably challenging. Therefore, an efficient and low-cost catalyst must be urgently developed to improve the efficiency of this process. In this study, a Co3O4–CeO2 composite oxide catalyst was successfully prepared through ultrasound-assisted co-precipitation. This catalyst exhibited a higher selectivity to KA-oil, which was benefited from the synergistic effects between Co3+/Co2+ and Ce4+/Ce3+ redox pairs, than bulk CeO2 and/or Co3O4. Under the optimum reaction conditions, 89.6% selectivity to KA-oil with a cyclohexane conversion of 5.8% was achieved over Co3O4–CeO2. Its catalytic performance remained unchanged after five runs. Using the synergistic effects between the redox pairs of different transition metals, this study provides a feasible strategy to design high-performance catalysts for the selective oxidation of alkanes.

关键词: Co3O4–CeO2 composite oxides     cyclohexanone     cyclohexanol     ultrasonic-assisted co-precipitation     selective oxidation     solvent-free    

标题 作者 时间 类型 操作

Enhancing the aromatic selectivity of cyclohexane aromatization by CO2 coupling

期刊论文

Studies on QSAR of metalloporphyrin catalysts in the oxidation of cyclohexane to adipic acid

CHEN Yixia, SHE Yuanbin, XU Jing, LI Yan

期刊论文

Highly selective catalytic hydrodeoxygenation of guaiacol to cyclohexane over Pt/TiO

Zhong HE,Xianqin WANG

期刊论文

Conversion of phenol to cyclohexane in the aqueous phase over Ni/zeolite bi-functional catalysts

Jimei Zhang, Fuping Tian, Junwen Chen, Yanchun Shi, Hongbin Cao, Pengge Ning, Shanshan Sun, Yongbing Xie

期刊论文

Advances and perspectives in catalysts for liquid-phase oxidation of cyclohexane

Hui LI, Yuanbin SHE, Tao WANG

期刊论文

One-step synthesis of

Kuiyi YOU, Fangfang ZHAO, Xueyan LONG, Pingle LIU, Qiuhong AI, Hean LUO

期刊论文

新型苯加氢反应器的研究

A.M.Anter,程振民,肖琼,胡劲松,袁渭康

期刊论文

co-precipitation synthesis of mesoporous Co3O4–CeO2 composite oxides for highly selective catalytic oxidation of cyclohexane

期刊论文