C:Corrosive;
142-62-1Relevant articles and documents
Highly Selective Silica-supported Copper Catalysts Derived from Copper Phyllosilicates in the Hydrogenation of Adipic Acid to 1,6-hexanediol
Jiang, Jia-Wei,Tu, Cheng-Chieh,Chen, Chao-Huang,Lin, Yu-Chuan
, p. 5449 - 5458 (2018)
Hydrogenation of adipic acid (AA) is a potential way to prepare 1,6-hexanediol (HDOL). Herein, silica-supported copper catalysts derived from copper phyllosilicates were synthesized, characterized, and tested in the hydrogenation of AA to HDOL. In a full conversion of AA, a high yield of HDOL (approximately 90 %) was obtained through the use of each Cu-based catalyst. The turnover frequency calculated according to the consumption rate of AA was discovered to be dependent on the Cu+/(Cu0+Cu+) ratio and the reduction condition. Moreover, recycling tests showed that a catalyst derived from a copper phyllosilicate had better stability compared with Cu/SiO2 made through impregnation due to a stronger interaction between Cu and silica. The kinetic analyses based on the global rate expression and Langmuir?Hinshelwood?Hougen?Watson (LHHW) formalism of AA conversion were conducted. The possible competitive adsorption between AA and its derivatives, including hydroxycaproic acid and ?-caprolactone, was thereby revealed.
Alkoxy-1,3,5-triazapentadien(e/ato) copper(II) complexes: Template formation and applications for the preparation of pyrimidines and as catalysts for oxidation of alcohols to carbonyl products
Kopylovich, Maximilian N.,Karabach, Yauhen Yu.,Guedes Da Silva, M. Fatima C.,Figiel, Pawel J.,Lasri, Jamal,Pombeiro, Armando J. L.
, p. 899 - 914 (2012)
Template combination of copper acetate (Cu(AcO)2·H 2O) with sodium dicyanamide (NaN(C≡N)2, 2 equiv) or cyanoguanidine (N≡CNHC(=NH)NH2, 2 equiv) and an alcohol ROH (used also as solvent) leads to the neutral copper(II)-(2,4-alkoxy-1,3,5- triazapentadienato) complexes [Cu{NH=C(OR)NC(OR)=NH}2] (R=Me (1), Et (2), nPr (3), iPr (4), CH2CH2OCH3 (5)) or cationic copper(II)-(2-alkoxy-4-amino-1,3,5-triazapentadiene) complexes [Cu{NH=C(OR)NHC(NH2)=NH}2](AcO)2 (R=Me (6), Et (7), nPr (8), nBu (9), CH2CH2OCH3 (10)), respectively. Several intermediates of this reaction were isolated and a pathway was proposed. The deprotonation of 6-10 with NaOH allows their transformation to the corresponding neutral triazapentadienates [Cu{NH=C(OR)NC(NH 2)=NH}2] 11-15. Reaction of 11, 12 or 15 with acetyl acetone (MeC(=O)CH2C(=O)Me) leads to liberation of the corresponding pyrimidines NC(Me)CHC(Me)NCNHC(=NH)OR, whereas the same treatment of the cationic complexes 6, 7 or 10 allows the corresponding metal-free triazapentadiene salts {NH2C(OR)=NC(NH2)=NH 2}(OAc) to be isolated. The alkoxy-1,3,5-triazapentadiene/ato copper(II) complexes have been applied as efficient catalysts for the TEMPO radical-mediated mild aerobic oxidation of alcohols to the corresponding aldehydes (molar yields of aldehydes of up to 100% with >99% selectivity) and for the solvent-free microwave-assisted synthesis of ketones from secondary alcohols with tert-butylhydroperoxide as oxidant (yields of up to 97%, turnover numbers of up to 485 and turnover frequencies of up to 1170 h-1). One pot for the lot: Alkoxy-1,3,5-triazapentadien(e/ato)-CuII complexes have been synthesised by one-pot template synthesis, used for metal-mediated synthesis of pyrimidines and triazapentadienes, and shown to be effective catalysts in the oxidation of alcohols to carbonyl products (see scheme). Copyright
Solvent-free microwave-assisted peroxidative oxidation of secondary alcohols to the corresponding ketones catalyzed by copper(ii) 2,4-alkoxy-1,3,5-triazapentadienato complexes
Figiel, Pawel J.,Kopylovich, Maximilian N.,Lasri, Jamal,Da Silva, M. Fatima C. Guedes,Da Silva, Joao J. R. Frausto,Pombeiro, Armando J. L.
, p. 2766 - 2768 (2010)
A facile, efficient and selective solvent-free synthesis of ketones from secondary alcohols with tert-butylhydroperoxide (TBHP) as the oxidant under microwave irradiation is achieved, where the copper(ii) 2,4-alkoxy-1,3,5- triazapentadienato complexes are efficient catalysts providing high yields (up to 100%), TONs (up to 890) and TOFs (up to 1780 h-1).
MULTIFUNCTIONAL MICELLAR CATALYSIS AS A MODEL OF ENZYME ACTION.
Ihara,Nango,Kimura,Kuroki
, p. 1252 - 1255 (1983)
The rate constants of both the acylation and deacylation processes in the hydrolyses of p-nitrophenyl acetate (PNPA) and hexanoate (PNPH) by imidazole catalysts (1) in the presence of surfactant micelles (2) have been directly determined under single turnover conditions at pH 7. 30 in 0. 02 M phosphate buffer and 25 degree C. The major course of catalysts was the acylation followed by deacylation at the imidazole group. The kinetic analysis suggests that a multifunctional mode of action is involved in the catalystic ester hydrolysis; the acylation and deacylation rates are accelerated by carboxylate ion in the catalyst and by surfactant hydroxyl group, respectively.
Aroma compounds formed from 3-methyl-2,4-nonanedione under photooxidative conditions
Sigrist, Isabelle A.,Manzardo, Giuseppe G. G.,Amado, Renato
, p. 3426 - 3428 (2003)
The behavior of the prominent aroma compound 3-methyl-2,4-nonanedione under photooxidative conditions was investigated in a model experiment. The four well-known aroma compounds 2,3-butanedione, 2,3-octanedione, acetic acid, and caproic acid were identified. The main oxidation product was 3-hydroxy-3-methyl-2,4-nonanedione, an aroma compound with the odor description of rubbery, earthy, and plasticlike (GC-O). Its structure has been tentatively assigned based on mass (GC-MS) and vapor phase infrared spectra (GC-IR). The formal formation pathways are discussed for these compounds, and other origins described in the literature are presented.
Two-fold interpenetrating btc based cobaltous coordination polymer: A promising catalyst for solvent free oxidation of 1-hexene
Bora, Sanchay J.,Paul, Rima,Nandi, Mithun,Bhattacharyya, Pradip K.
, p. 38 - 44 (2017)
This work describes the synthesis of a new 2-D coordination polymer (CP), [Co3(btc)2(dmp)8]n (btc = 1,3,5-benzenetricarboxylate and dmp = 3,5-dimethylpyrazole) and its catalytic activity towards the oxidation reaction of 1-hexene to form oxygenated compounds under solvent free condition. Structural analysis reveals that Co(II) cations in this polymeric compound are linked by btc3- anions with alternate tetrahedral/octahedral coordination forming a two-fold interpenetrated 3-connected hcb underlying net. Electronic spectrum of the cobaltous polymer has been calculated using TDDFT/B3LYP method for making the appropriate assignments of electronic transitions. Catalytic results show good conversions of the starting material to oxygenated products with high selectivities for 1,2-epoxyhexane and 1-hexanal.
Organic solvent nanofiltration and adsorbents; A hybrid approach to achieve ultra low palladium contamination of post coupling reaction products
Pink, Christopher J.,Wong, Hau-To,Ferreira, Frederico C.,Livingston, Andrew G.
, p. 589 - 595 (2008)
Due to potentially toxic contamination of pharmaceutical products, effective removal of palladium from post-reaction solutions is of great importance, especially in the pharmaceutical industry. This work addresses this challenge by combining organic solvent nanofiltration (OSN) with adsorbents in a hybrid process. Post-reaction solutions resulting from acylation and Suzuki reactions were subjected to OSN, the catalyst was retained by the membrane, and the product was collected in the permeate. Palladium levels in the permeate were reduced further by using adsorbents. This technique achieved ultralow palladium concentration (-1 for post-reaction solutions with toluene and ethyl acetate as solvents. The results obtained using the hybrid OSN-adsorbent process were compared to those using selected adsorbents only. When palladium was removed from a post-Suzuki reaction solution, using polystyrenebound trimercaptotriazine as the adsorbent, the hybrid process, while using 10 times less adsorbent than the adsorbent-only process, was able to reduce the product contamination to an 8.5 times lower level. It is thought that the membrane stage of this technique removes bulky ligated palladium along with palladium nanoparticles, species that are hard to remove by adsorption only. The residual palladium in the permeate stream comprises well-dissolved, smaller molecules, and these are removed very effectively by the adsorbent. This allows high-purity products to be achieved by treatment of the OSN permeate with low amounts of absorbents. Therefore, this hybrid process is recommended for separations where adsorbent-only treatment can result in significant product losses, or where strong ligand-palladium interactions compete with adsorbent active sites, keeping palladium in solution.
Antioxidative activity of heterocyclic compounds found in coffee volatiles produced by Maillard reaction
Yanagimoto, Kenichi,Lee, Kwang-Geun,Ochi, Hirotomo,Shibamoto, Takayuki
, p. 5480 - 5484 (2002)
Typical heterocyclic compounds substituted with various functional groups found in Maillard reaction products were examined for antioxidant activity. Pyrroles exhibited the greatest antioxidant activity among all heterocyclic compounds tested. All pyrroles inhibited hexanal oxidation by almost 100% at a concentration of 50 μg/mL over 40 days. Addition of formyl and acetyl groups to a pyrrole ring enhanced antioxidative activity remarkably. Pyrrole-2-carboxaldehyde, 2-acetylpyrrole, 1-methyl-2-pyrrolecarboxaldehyde, and 2-acetyl-1-methylpyrrole inhibited hexanal oxidation by >80% at 10 μg/mL. Unsubstituted furan exhibited the greatest antioxidant activity among furans tested. Addition of all functional groups used in this study to furan decreased antioxidative activity. The antioxidant activity of thiophene increased with the addition of methyl and ethyl groups, but the addition of formyl or acetyl groups to thiophene decreased antioxidant activity. Thiazoles and pyrazines were ineffective antioxidants at all concentrations tested. Reaction of all heterocyclic compounds with hydrogen peroxide resulted in the formation of various oxidized products.
A Direct Conversion of (α-Hydroxyalkyl)silanes to Carboxylic Acids
Linderman, Russell J.,Chen, Kangyi
, p. 6767 - 6770 (1992)
(α-Hydroxyalkyl)trialkylsilanes and acylsilanes are readily oxidized to the corresponding carboxylic acid using ozone.
Biotransformation of linoleic acid into hydroxy fatty acids and carboxylic acids using a linoleate double bond hydratase as key enzyme
Oh, Hye-Jin,Kim, Sae-Um,Song, Ji-Won,Lee, Jung-Hoo,Kang, Woo-Ri,Jo, Ye-Seul,Kim, Kyoung-Rok,Bornscheuer, Uwe T.,Oh, Deok-Kun,Park, Jin-Byung
, p. 408 - 416 (2015)
Hydroxy fatty acids are used as starting materials for the production of secondary metabolites and signalling molecules as well as in the manufacture of industrial fine chemicals. However, these compounds are usually difficult to produce from renewable biomass by chemical means. In this study, linoleate double bond hydratases of Lactobacillus acidophilus NBRC 13951 were cloned for the first time. These enzymes were highly specific for the hydration of the C-9 or the C-12 double bond of unsaturated fatty acids (e.g., linoleic acid). Thereby, the enzymes allowed the selective production of hydroxy fatty acids such as 13-hydroxy- cis -9-octadecenoic acid and 10-hydroxy- cis -12-octadecenoic acid from linoleic acid. In addition, the hydroxy fatty acids were further converted into industrially relevant carboxylic acids (e.g., 12-hydroxy-cis-9-dodecenoic acid, a, w-tridec-9-enedioic acid) and lactones (i.e., d-decalactone, g-dodecelactone) via whole-cell biocatalysis using an enzyme cascade. This study thus contributes to the preparation of hydroxy fatty acids, unsaturated carboxylic acids, and lactones from renewable unsaturated fatty acids.
