- Ru/g-C3N4as an efficient catalyst for selective hydrogenation of aromatic diamines to alicyclic diamines
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A series of Ru/g-C3N4materials with highly dispersed Ru were firstly prepared by an ultrasonic impregnation method using carbon nitride as a support. The catalysts were characterized by various techniques including BET and elemental analysis, ICP-AES, XPS, XRD, CO2-TPD and TEM. The results demonstrated that Ru/g-C3N4materials with a mesoporous structure and highly dispersed Ru were successfully prepared. The chemo-selective hydrogenation ofp-phenylenediamine (PPDA) to 1,4-cyclohexanediamine (CHDA) over Ru/g-C3N4as a model reaction was investigated in detail. PPDA conversion of 100% with a CHDA selectivity of more than 86% could be achieved under mild conditions. It can be inferred that the carbon nitride support possessed abundant basic sites and the Ru/g-C3N4-Tcatalysts provided suitable basicity for the aromatic ring hydrogenation. Compared to the N-free Ru/C catalyst, the involvement of nitrogen species in Ru/g-C3N4remarkably improved the catalytic performance. In addition, the recyclability of the catalyst demonstrated that the aggregation of Ru nanoparticles was responsible for the decrease of the catalytic activity. Furthermore, this strategy also could be expanded to the selective hydrogenation of other aromatic diamines to alicyclic diamines.
- Cao, Junya,Cao, Yan,Chen, Jiaqiang,Han, Fenggang,He, Peng,Huang, Xiaoyu,Li, Huiquan,Wang, Liguo,Yang, Huanhuan
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p. 16515 - 16525
(2020/05/13)
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- Enhanced Selectivity in the Hydrogenation of Anilines to Cyclo-aliphatic Primary Amines over Lithium-Modified Ru/CNT Catalysts
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The hydrogenation of aromatic amines to the corresponding cycloaliphatic primary amines is an important industrial reaction. However, secondary amine formation and other side reactions are frequently observed, resulting in reduced selectivity. The side products are formed mostly on the support, yet support effects are little understood at present. This study describes the facile modification of Ru/CNT catalysts with LiOH, by this means significantly improving catalyst selectivity in toluidine hydrogenation without decreasing the activity of the catalysts. The effect is explained by LiOH diminishing acidic sites on the catalyst support and enhancing the adsorption of the aromatic ring on the metallic ruthenium nanoparticles. With the LiOH-modified Ru/CNT catalyst, other substrates, such as methylnitrobenzenes, are also converted efficiently. This study thus describes an improved catalyst for the preparation of cyclohexylamines and provides guidelines for future catalyst design.
- Tomkins, Patrick,Müller, Thomas E.
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p. 1438 - 1445
(2018/03/30)
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- A method for the preparation of amine curing agent
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The invention discloses a preparation method of alicyclic amine curing agent. The method includes steps of dissolving methylphenylenediamine, as a raw material, in an organic solvent and performing a reaction with stirring for 5-12 hours in the presence o
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Paragraph 0023; 0024; 0028; 0029; 0030; 0031
(2017/04/29)
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- Alicyclic amine curing agent for the preparation of
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The invention discloses a preparation method of an alicyclic amine curing agent, which comprises the following steps: dissolving the raw material methyl phenylenediamine in an organic solvent; and in the presence of a supported metal catalyst, stirring to
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Paragraph 0017; 0018; 0022-0025
(2017/12/27)
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- Preparation method of methylcyclohexanediamine
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The invention discloses a preparation method of methylcyclohexanediamine, wherein the preparation method comprises: dissolving methylphenylenediamine as a material in an organic solvent, and stirring and reacting at 150-200 DEG C under hydrogen pressure of 8-12 Mpa in the presence of a supporting metal catalyst and an inorganic salt aid for 5-10 hours to obtain the methylphenylenediamine. The preparation method provided herein solves the problems that existing preparation process of methylcyclohexanediamine is low in capacity and brings mass byproducts, and popularization of this product in more fields is reliably guaranteed.
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Paragraph 0026
(2017/04/03)
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- One pot catalytic NO2 reduction, ring hydrogenation, and N-alkylation from nitroarenes to generate alicyclic amines using Ru/C-NaNO 2
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A report to produce alicyclic amines and subsequent N-alkylation with alcohols using Ru/C-NaNO2 catalyzed facile transformation of nitrobenzene was investigated. Effects of solvent, temperature, pressure, reaction time, and molar-ratio of substrate/catalyst on product composition were also studied. These mechanistic studies explain that nitrobenzene undergoes hydrogenation reaction in the following order; -NO2 reduction to -NH2, aromatic ring-hydrogenation to alicyclic, and from the reaction of alcohol to give N-alkylated amines. This investigation shed lights on possible application to polyurethane chemistry since these amines are used as important precursors for diisocyanates.
- Oh, Seung Geun,Mishra, Vivek,Cho, Jin Ku,Kim, Baek-Jin,Kim, Hoon Sik,Suh, Young-Woong,Lee, Hyunjoo,Park, Ho Seok,Kim, Yong Jin
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- METHOD OF CONVEYING LIQUIDS
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The present invention relates to a method of continuously conveying a liquid which is used as starting material in a chemical reaction by means of a displacement pump having physically separate forward-transport valves and a liquid-filled bidirectional flow line between displacement pump and forward-transport valves, wherein an auxiliary liquid which is a product or a starting material of the chemical reaction and has a melting point which is below the melting point or below the saturation temperature of the liquid to be conveyed is present in the bidirectional flow line. The present invention additionally provides for the use of a product formed by hydrogenation of an aromatic compound as auxiliary liquid for conveying an aromatic compound and also the use of an alcohol or an ester derived from alcohol and carboxylic acid as auxiliary liquid for conveying carboxylic acids or carboxylic acid derivatives.
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Page/Page column 8
(2012/05/20)
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- N,N-bis (quinolin-4-yl)-diamine derivatives, their preparation and their use as antimalarials
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Disclosed are N,N'-bis(quinolin-4-yl)diamine derivatives of general formula I wherein R1 signifies halogen or trifluoromethyl, R2 signifies hydrogen or halogen, A signifies cyclohexane-1,3-diyl, 2-methyl-cyclohexane-1,3-diyl, cyclohexane-1,4-diyl, dicyclohexylmethane-4,4'-diyl, cyclopentane-1,3-diyl, phenylene-1,4, phenylene-1,3 and phenylene-1,2; n is 1 or 2; m is 1 or 2, as well as their pharmaceutically acceptable salts. These products are useful as agents for preventing malaria and for treating it, especially where the pathogens are resistant to chloroquine. STR1
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