- Synthesis of CoFe2O4@Pd/Activated carbon nanocomposite as a recoverable catalyst for the reduction of nitroarenes in water
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Efficient reduction of nitro compounds into amines is an important industrial transformation. So, it is a great deal to design new catalysts for efficient reduction of the nitro compounds especially in water. In this work, a new magnetic Pd/activated carbon nanocomposite (CoFe2O4@Pd/AC) was synthesized via metal-impregnation-pyrolysis method. The CoFe2O4@Pd/AC was fully characterized by FT-IR, PXRD, FESEM, TEM, VSM, EDX-mapping and BET techniques. The results showed that CoFe2O4@Pd/AC is a highly reactive and easily recoverable magnetic catalyst for the reduction of the nitro compounds by using NaBH4 in water. For instance, aniline was obtained in high yield (99%) after 75 ?min at 25 ?C by using just 6 ?mg of the catalyst. In addition, CoFe2O4@Pd/AC was recovered by a simple magnetic decantation and it exhibits stable activity and remains intact during the catalytic process with no significant loss in activity (8 cycles).
- Hamadi, Hosein,Kazeminezhad, Iraj,Mohammadian, Sara
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- Heterogeneous AgPd Alloy Nanocatalyst for Selective Reduction of Aromatic Nitro Compounds Using Formic Acid as Hydrogen Source
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Abstract: A Heterogeneous catalyst developed for selective reduction of nitroarenes to the analogous anilines using formic acid as hydrogen source. This catalytic procedure offers a simplistic path to prepare aromatic amines in good to excellent yields. Especially, even anilines functionalized with other potentially reducible moieties are obtained with high selectivity. Herein, we report convenient and stable bimetallic AgPd nanocatalyst supported on metal organic framework coated with polyaniline. Hydrogenation of nitroarenes gave analogues anilines with excellent yields at 90?°C in 6?h with no use of additives. Catalyst maintained stable performance in five repeated cycles. Graphic Abstract: [Figure not available: see fulltext.].
- Babel, Vikram,Hiran
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p. 1865 - 1869
(2020/01/28)
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- A polyamine dendritic polymer-copper complex: A reusable catalyst for the additive-free amination of aryl bromides, and iodides
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A porphyrin-initiated amine-functionalized polyepichlorohydrin dendritic polymer (PPECH-Amine) was effectively synthesized, and its water-soluble copper complex (PPECH-Amine-Cu) was developed by treating it with copper acetate. PPECH-Amine and PPECH-Amine-Cu were characterised by different spectroscopic and microscopic techniques. PPECH-Amine-Cu was identified as a reusable catalyst for the amination of bromo- and iodo-benzene derivatives in aqueous media. Due to the presence of residual amino groups in the PPECH-Amine-Cu catalyst, the protocol does not need any additional base additive, as ammonia itself acts as a base and a coupling partner. Due to the good water-soluble nature of this catalyst, it can be easily separated and reused up to six reaction cycles without any loss in its activity.
- Avudaiappan,Palmurukan,Unnikrishnan,Sreekumar
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p. 1477 - 1484
(2020/02/05)
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- Mechanochemical catalytic transfer hydrogenation of aromatic nitro derivatives
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Mechanochemical ball milling catalytic transfer hydrogenation (CTH) of aromatic nitro compounds using readily available and cheap ammonium formate as the hydrogen source is demonstrated as a simple, facile and clean approach for the synthesis of substituted anilines and selected pharmaceutically relevant compounds. The scope of mechanochemical CTH is broad, as the reduction conditions tolerate various functionalities, for example nitro, amino, hydroxy, carbonyl, amide, urea, amino acid and heterocyclic. The presented methodology was also successfully integrated with other types of chemical reactions previously carried out mechanochemically, such as amide bond formation by coupling amines with acyl chlorides or anhydrides and click-type coupling reactions between amines and iso(thio)cyanates. In this way, we showed that active pharmaceutical ingredients Procainamide and Paracetamol could be synthesized from the respective nitro-precursors on milligram and gram scale in excellent isolated yields.
- Portada, Tomislav,Margeti?, Davor,?trukil, Vjekoslav
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supporting information
(2018/12/11)
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- Preparation method of 3,5-diaminobenzoic acid
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The invention discloses a preparation method of 3,5-diaminobenzoic acid. The preparation method comprises steps as follows: m-dinitrobenzoic acid and hydrogen are subjected to a reduction reaction in a solvent under the action of a hydrogenation catalyst, and after the reaction, 3,5-diaminobenzoic acid is obtained through treatment, wherein the hydrogenation catalyst is an Ni-M-Al three-way catalyst, and M is La, Yb or Ce. According to the preparation method of 3,5-diaminobenzoic acid, the new three-way catalyst is adopted as the hydrogenation catalyst, the pressure of hydrogenation is effectively reduced, meanwhile, the usage quantity of the catalyst is reduced, and accordingly, 3,5-diaminobenzoic acid prepared through catalytic hydrogenation has higher industrial application value.
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Paragraph 0025; 0026; 0031; 0036; 0040; 0045; 0053
(2018/02/04)
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- Rapid, efficient and selective reduction of aromatic nitro compounds with hydrazine hydrate in the presence of the plain and supported platinum nanoparticles as catalysts
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The current study aimed at application of the plain and supported platinum nanoparticles as a heterogenous catalyst for the reduction of aromatic nitro compounds. Monodispersed platinum nanoparticles were synthesized by reduction of H2PtCl6 by ethanol in the presence of polyvinyl pyrrolidone as a stabilizer, and then were immobilized on four types of zeolites. The obtained catalyst granules were characterized by X-ray diffractometry and transmission electron microscopy. The study then focused on elaboration of the catalytic activity of the nano catalysts under different operational conditions. It was found that reaction is adequately rapid at ambient temperature, and by utilizing a sufficient amount of catalyst, can be completed in nearly 30 min. Among the utilized zeolitic supports, zeolite 4A had the highest performance, but the mechanism of its synergetic effect on the activity of platinum nano catalyst was not found and requires more investigation.
- Mehdizadeh, Soofia,Ahmadi, Seyed Javad,Sadjadi, Sodeh,Outokesh, Mohammad
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p. 1587 - 1592
(2015/01/09)
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- Sustainable chemical process for reduction of nitro compounds (R-NO2) or nitroso compounds (R-NO) containing sulphonic or carboxylic group into corresponding amino compounds (R-NH2) with inherent recycle of all acidic streams generated in synthesis
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The process of the present invention creates a sustainable and closed water loop allowing inherent recycles of all liquid streams generated in the process. The liquid streams generated during the process of the invention are inherently recycled completely, making the process of the present invention a zero liquid discharge process which is environmentally friendly and sustainable. This invention further relates to a sustainable chemical process of reduction of R—NO2 or R—NO into corresponding R—NH2 that produces environmentally friendly R—NH2 in good yields and selectivity with large of mother liquor recycle. The process has a wide scope in that it can be applied to a number of molecules.
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Page/Page column 12-14
(2012/08/27)
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- Method for estimating SN1 rate constants: Solvolytic reactivity of benzoates
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Nucleofugalities of pentafluorobenzoate (PFB) and 2,4,6-trifluorobenzoate (TFB) leaving groups have been derived from the solvolysis rate constants of X,Y-substituted benzhydryl PFBs and TFBs measured in a series of aqueous solvents, by applying the LFER equation: log k = sf(Ef + Nf). The heterolysis rate constants of dianisylmethyl PFB and TFB, and those determined for 10 more dianisylmethyl benzoates in aqueous ethanol, constitute a set of reference benzoates whose experimental ΔG ? have been correlated with the ΔH? (calculated by PCM quantum-chemical method) of the model epoxy ring formation. Because of the excellent correlation (r = 0.997), the method for calculating the nucleofugalities of substituted benzoate LGs have been established, ultimately providing a method for determination of the SN1 reactivity for any benzoate in a given solvent. Using the ΔG? vs ΔH? correlation, and taking sf based on similarity, the nucleofugality parameters for about 70 benzoates have been determined in 90%, 80%, and 70% aqueous ethanol. The calculated intrinsic barriers for substituted benzoate leaving groups show that substrates producing more stabilized LGs proceed over lower intrinsic barriers. Substituents on the phenyl ring affect the solvolysis rate of benzhydryl benzoates by both field and inductive effects.
- Matic, Mirela,Denegri, Bernard,Kronja, Olga
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supporting information
p. 8986 - 8998,13
(2012/12/12)
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- SUSTAINABLE CHEMICAL PROCESS FOR REDUCTION OF NITRO COMPOUNDS (R-NO2) OR NITROSO COMPOUNDS (R-NO) CONTAINING SULPHONIC OR CARBOXYLIC GROUP INTO CORRESPONDING AMINO COMPOUNDS (R-NH2) WITH INHERENT RECYCLE OF ALL ACIDIC STREAMS GENERATED IN SYNTHESIS
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The process of the present invention creates a sustainable and closed water loop allowing inherent recycles of all liquid streams generated in the process. The liquid streams generated during the process of the invention are inherently recycled completely, making the process of the present invention a zero liquid discharge process which is environmentally friendly and sustainable. This invention further relates to a sustainable chemical process of reduction of R- NO2 or R-NO into corresponding R-NH2 that produces environmentally friendly R-NH2 in good yields and selectivity with large of mother liquor recycle. The process has a wide scope in that it can be applied to a number of molecules.
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Page/Page column 40-42
(2011/05/06)
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- Synthesis and characterization of ruthenium(III) chloride complexes with some 1,2-disubstituted benzimidazoles and their catalytic activity
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Reaction of ruthenium(III) chloride with 2-mono substituted and 1,2-disubstituted benzimidazoles yield the complexes of the formulae RuCl 3Ly.nH2O [L = 2-o-hydroxyphenylbenzimidazole (oHPB), y = 3, n = 0; L = 2-p-hydroxyphenylbenzimidazole (pHPB), y = 2, n = 3], and RuCl3L2.H2O [L = 1-o-hydroxybenzyl-2-o-hydroxyphenylbenzimidazole (oHBPB), 1-m-hydroxybenzyl-2-m-hydroxyphenylbenzimidazole (mHBPB), and 1-p-hydroxybenzyl-2-p-hydroxyphenylbenzimidazole (pHBPB)]. The complexes are characterized by elemental analysis, conductivity measurements, infrared, electronic, 1H- and 13C-NMR spectral studies, as well as by thermal analysis. The complexes exhibit octahedral geometry. Some of the complexes act as potential catalyst towards transferhydrogenation. Copyright Taylor & Francis Group, LLC.
- Krishnamurthy
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scheme or table
p. 590 - 597
(2011/10/03)
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- A new class of heterogeneous platinum catalysts for the chemoselective hydrogenation of nitroarenes
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A new series of nanostructured platinum catalysts able to catalyze the selective reduction of nitroarenes has been developed. The materials, made of organosilica physically doped with nanostructured platinum(0), are stable and efficient. Reactions in general proceed with high yield and often go to completion, while the catalysts can be reused in further reaction runs. This establishes a new class of relevant solid catalysts for synthetic organic chemistry named SiliaCat Platinum-Hydrogel.
- Pandarus, Valerica,Ciriminna, Rosaria,Beland, Francois,Pagliaro, Mario
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scheme or table
p. 1306 - 1316
(2011/06/25)
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- A new reagent for selective reduction of nitro group
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The nitro group in aromatic nitro compounds containing reducible substitucnts such as methyl, carboxylic acids and phcnols, and halogcns arc selectively and rapidly reduced at room temperature to the corresponding amines in good yield by employing hydrazine glyoxylatc in the presence of zinc powder or magnesium powder. It has been observed that hydrazine glyoxylatc is more effective than hydrazine, glyoxylic acid, hydrazinium monoformate or ammonium monoformate and reduction of the nitro group occurs without hydrogcnolysis in the presence of low-cost magnesium compared to expensive metals like palladium, platinum, ruthenium, etc. The products have been characterized by comparison of their TLC, infrared spectra and melting points.
- Raju,Ragul,Sivasankar
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experimental part
p. 1315 - 1318
(2010/01/16)
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- Photochemical reactivity of trifluoromethyl aromatic amines: The example of 3,5-diamino-trifluoromethyl-benzene (3,5-DABTF)
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This work presents the application of an on-line photoreactor to the detection of 3,5-diamino-trifluoromethyl-benzene (3,5-DABTF) in aqueous solutions. When irradiated at 310 nm, this compound is defluorinated to 3,5-diaminobenzoic acid by a nucleophilic substitution of the fluoride by water. Concomitantly, defluorination intermediates polymerize through amide bonds to give dark-colored compounds. We take advantage of the photocatalyzed defluorination and the subsequent decrease in pH to develop an original and specific photoreactor. Continuous recording of pH and temperature in the outlet of the reactor by a dual electrode gives us an opportunity to optimize the system. In the photoreactor, 3,5-DABTF is immediately and totally transformed as attested by the rapid drop of the flowing solution pH from 6.2 to 3.2 and the chromatographic analysis of the outgoing solutions. The detection remains effective from 1 to 1000 parts per million.
- Chaignon, Philippe,Cortial, Sylvie,Guerineau, Vincent,Adeline, Marie-Therese,Giannotti, Charles,Fan, Gerard,Ouazzani, Jamal
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p. 1539 - 1543
(2008/02/01)
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- Hydrazinium monoformate: A new hydrogen donor. Selective reduction of nitrocompounds catalyzed by commercial zinc dust
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The nitro group in aliphatic and aromatic nitro compounds also containing reducible substituents such as ethene, nitrile, acid, phenol, halogen, ester, etc., are selectively and rapidly reduced at room temperature to corresponding amines in good yields by employing hydrazinium monoformate, in the presence of commercial zinc dust. It was observed that, hydrazinium monoformate is more effective than hydrazine or formic acid and reduction of nitro group occurs without hydrogenolysis in the low cost zinc dust compared to expensive metals like palladium.
- Gowda, Shankare,Gowda, B. K. Kempe,Gowda, D. Channe
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p. 281 - 289
(2007/10/03)
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- Catalytic transfer hydrogenation of aromatic nitro compounds by employing ammonium formate and 5% platinum on carbon
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Aromatic nitro compounds were reduced to respective amines in high yields by using 5% platinum on carbon with ammonium formate or formic acid as hydrogen donor. It was observed that the former was mote efficient donor than the later. Further we have found that reduction of nitro groups occurs without hydrogenolysis of halogens and the reducible substituents which remains unchanged under the reaction conditions.
- Gowda,Mahesh
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p. 3639 - 3644
(2007/10/03)
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- Formic acid with 10% palladium on carbon: A reagent for selective reduction of aromatic nitro compounds
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The nitro group in aromatic nitro compounds also containing reducible substituents such as carbonyl, ethene, ethyne, nitrile, acid, phenol etc, is selectively and rapidly reduced at room temperature to corresponding amino derivatives in good yield employing formic acid in the presence of 10% palladium on carbon. The catalyst could be recovered and reused after washing with water and ethanol, and the results obtained indicate further, there is no apparent loss of catalytic activity.
- Channe Gowda,Gowda
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p. 709 - 711
(2007/10/03)
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- Triazinyl reactive dyestuffs in which triazinyl group is further substituted with a beta-chloroethylsulfonyl- or vinylsulfonylbutyrylamino moiety
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Reactive dyes of the formula STR1 in which D is the radical of an organic dye of the monoazo, polyazo, metal complex azo, anthraquinone, phthalocyanine, formazan, azomethine, dioxazine, phenazine, stilbene, triphenylmethane, xanthene, thioxanthrone, nitroaryl, naphthoquinone, pyrenequinone or perylenetetracarbimide series, R is hydrogen or substituted or unsubstituted C1-4 -alkyl, X is a substituent which is detachable as an anion, B is a radical of the formula STR2 R1 and R2, independently of each other, are hydrogen or substituted or unsubstituted C1-4 -alkyl or phenyl, A is a substituted or unsubstituted aliphatic or aromatic bridge member, Y is a --CO--Z or --SO2 --Z radical, Z is an aliphatic, aromatic or heterocyclic reactive radical, and n is 1 or 2, are suitable for dyeing or printing cellulose-containing and nitrogen-containing materials and in high dyeing yield produce dyeings and prints having good fastness properties.
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- Radiopharmaceutical composition based on technetium-99m and reagent for making it
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Radiopharmaceutical compositions containing complexes of technetium-99m with a complexing agent are prone to time and activity-related decomposition and formation of pertechnetate. Stabilizing agents for such complexes are organic compounds having an amine group and a carboxylic acid group attached to an aromatic ring. A preferred stabilizing agent is the sodium salt of 4-aminobenzoic acid. There are claims to a composition comprising a technetium 99-m complex stabilized by means of the said stabilizing agent; and to a reagent which forms, on addition of an aqueous solution of pertechnetate, a radiopharmaceutical composition, which reagent comprises a tin metal or stannous reducing agent for the pertechnetate, a complexing agent for the reduced technetium, for example a phosphorus-containing bone scanning agent, and a stabilizing agent as defined.
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- Reactive dyeing systems using dyes with carboxylic acid groups
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Carboxy substituted aromatic chromophores are reactively linked to fibers containing alcoholic hydroxyl groups, amino groups or thiol groups, such as cellulosic fibers, with the linkage produced in the presence of a cyanamide compound, such as cyanamide or dicyandiamide.
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