JOURNAL OF CATALYSIS
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2025
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IF 6.5
Lumei Wang,Dezhang Ren,Junyu Lang,Kangqi Gao,Xiao Du,Yong Yang,Zhibao Huo
Although homogeneous acid catalysts have been widely utilized in the production of solketal from glycerol, a significant aspect of the biodiesel industry, challenges remain, including the high corrosiveness of the catalysts and their excessive usage. In this study, a composite material of wCo(NO 3 ) 2 /γ-Al 2 O 3 was synthesized through an adsorption–desorption approach based on wet impregnation, achieving a Co(II) loading of only 1.8 wt%, which demonstrated a solketal yield of 84 % at 80 °C, significantly outperforming the catalytic activity of Co(NO 3 ) 2 . Even when the amount of Co(NO 3 ) 2 was increased to 22-fold that of the Co(II) content in wCo(NO 3 ) 2 /γ-Al 2 O 3 , the solketal yield only reached 67 %. Through systematic physicochemical characterization and theoretical calculations, it is revealed that Co(NO 3 ) 2 can be uniformly dispersed in an amorphous state on the surface of γ-Al 2 O 3 . Furthermore, γ-Al 2 O 3 facilitates a reduction in the orbital binding energy of Co and N within Co(NO 3 ) 2 . The synergistic effects of Co(II), NO 3 − , and γ-Al 2 O 3 contribute to decreasing the rate-determining energy of the ketalization reaction, thereby promoting the dehydration reactions of glycerol and acetone. Furthermore, this strategy is equally applicable to other soluble Co, Ni, and Cu salts, demonstrating universality. This method effectively reduces the usage of metal salts in the solketal synthesis process, enhancing the acid catalytic activity of the metal salts, providing an adsorption–desorption approach based on wet impregnation for the development of low-dose, highly active, and low-corrosive acid catalytic materials.
研究领域:
化学工程
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催化材料科学
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DOI
高影响因子
ACS Catalysis
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2018
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IF 11.384
Cheng Liang,Qiyi Ma,Haoran Yuan,Yongtao Wang,Jianyong Mao,Zhirong Chen,Jia Yao,Haoran Li
An investigation of aerobic oxidation of 2-methoxy-4-methylphenol to vanillin catalyzed by a number of cobalt salts, complexes, oxides, and hydroxides in alkaline solutions is reported. A good yield of vanillin (90%) was obtained when CoCl2 was used as the catalyst, while a poor yield (6%) was obtained with Co3O4. Unexpectedly, however, the Co3O4 catalytic activity was restored after heating in an alcoholic solution of NaOH for 24 h, producing a good yield of vanillin (85%). The recovered catalytic activity of Co3O4 indicated a conversion of inactivated heterogeneous particles to activated particles. In addition, precipitates were generated when “homogeneous” CoCl2 was employed as a catalyst, making us wonder about the true nature of the catalyst in this reaction. A series of experiments are described, including kinetic studies, filtration tests, centrifugation tests, dynamic light scattering, transmission electron microscopy, X-ray photoelectron spectroscopy, and powder X-ray diffraction, for the investigation of the true catalyst under catalytic conditions. The key observations led to the conclusion that the cobalt salts and complexes act as precatalysts that transform to cobalt oxide/hydroxide [CoOx(OH)y] nanoparticles, which is responsible for the benzylic C(sp3)–H oxyfunctionalization of 2-methoxy-4-methylphenol. Additionally, the size of the particles is decisive for catalyst performance. The nature of the active nanoparticles was also studied. With regard to the identification of homogeneous or heterogeneous catalysis, this study provides a complement to existing catalytic reaction types.
研究领域:
化学工程
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催化科学
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材料科学
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产品关联
DOI
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
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2023
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IF 6
Wenpeng Hong,Yu Zhang,Jiaxing Song,Haipeng Liu,Ling Zhang,Hang Wang,Yan Zhang,Haifeng Jiang
The extraction of phenolic compounds from biomass is an important way to replace chemical synthesis techniques, and catalytic pyrolysis of biomass is an effective method to obtain phenolic compounds with high selectivity. In this work, cobalt-modified montmorillonite K-10(CMT) catalyst was prepared by using cobalt salt and montmorillonite K-10(MMT), and used to catalyze the pyrolysis of corn stalk(CS) to produce phenol-rich bio-oil. The catalytic pyrolysis characteristics reflected by the liquid and gaseous components were compared using gas chromatography-mass spectrometry(GC-MS) and online mass spectrometry(online MS), and the catalytic pyrolysis behavior of corn stalk was analyzed by using the thermogravimetric analyzer(TGA). The addition of catalyst resulted in the increase of apparent activation energy of pyrolysis process but increased selectivity for phenolic compounds. Compared with the blank sample, the relative content of phenolic compounds in bio-oil increased by 11.99 %, and the selectivity of alkyl-phenols was stronger. In addition, the results also showed that the synthesized catalyst promoted the production of H 2 and CH 4 during the catalytic pyrolysis. The optimum ratio of the prepared catalyst was 6%Co/15%MMT. These works provide an alternative approach to upgrading bio-oil product.
研究领域:
能源与燃料化学
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催化材料科学
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DOI
高影响因子
Jove-Journal of Visualized Experiments
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2017
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IF 1.232
Junlian Wang,Meiying Xie,Xinyu Liu,Shengming Xu
We present the synthesis of (2,3-dimethylbutyl)(2,4,4'-trimethylpentyl)phosphinic acid as an example to demonstrate a method for the synthesis of high purity nonsymmetric dialkylphosphinic acid extractants. Low toxic sodium hypophosphite was chosen as the phosphorus source to react with olefin A (2,3-dimethyl-1-butene) to generate a monoalkylphosphinic acid intermediate. Amantadine was adopted to remove the dialkylphosphinic acid byproduct, as only the monoalkylphosphinic acid can react with amantadine to form an amantadine∙mono-alkylphosphinic acid salt, while the dialkylphosphinic acid cannot react with amantadine due to its large steric hindrance. The purified monoalkylphosphinic acid was then reacted with olefin B (diisobutylene) to yield nonsymmetric dialkylphosphinic acid (NSDAPA). The unreacted monoalkylphosphinic acid can be easily removed by a simple base-acid post-treatment and other organic impurities can be separated out through the precipitation of the cobalt salt. The structure of the (2,3-dimethylbutyl)(2,4,4'-trimethylpentyl)phosphinic acid was confirmed by 31P NMR, 1H NMR, ESI-MS, and FT-IR. The purity was determined by a potentiometric titration method, and the results indicate that the purity can exceed 96%.
研究领域:
有机化学
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分析化学
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产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）