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Transition metal-catalyzed hydrogenation
Published in Ilya D. Gridnev, Pavel A. Dub, Enantioselection in Asymmetric Catalysis, 2016
The Noyori–Ikariya (pre)catalyst 2 or similar complexes exist as mixtures of two diastereomers originating from the relative configuration on the metal atom.347,348 For example, the real intermediate of the catalytic cycle, hydride complex RuH[(R, R)-N(Ts)CH(Ph)CH(Ph)NH2](η6-p-cymene) exists as a 99:1 mixture of SRu and RRu-diastereomers in toluene-d8 at room temperature.264 Taking into account the absolute configuration of the NTs nitrogen atom and three stable five-membered NN ring conformations,349,350 there are 12 possible conformers available for the delivery of each S- and R-conFigured product, Chart 1.4.
SOLVENT SELECTION CRITERIA
Published in Nicholas P. Cheremisinoff, Industrial Solvents Handbook, Revised And Expanded, 2003
Solvent3Da.5HN,N-Dimethyl acetamide 16.8 11.5 10.2N, N-Dimethylethano lamine 13.58.6 13.9N,N-Dimethylformamide 17.4 13.7 11.3o-Dichlorobenzene 19.36.4 3.3o-Xy!ene 17.81 3.1p-Cymene (4-isopropyI toluene) 16.60.6 0.0Propionitrile 15.3 14.3 5.5Propylene carbonate (Texacar pc) 20.0 18.0 4.1Propylene glycol 16.89.4 23.3Propylene glycol butylene glycol n-butyl ether 15.65.5 7.8Propylene glycol diacetate 15.83.5 8.8Propylene glycol dimethyl ether 14.25.0 4.9Propylene glycol ethyl ether 15.47.0 13.5Propylene glycol ethyl methyl ether 14.44.2 3.7Propylene glycol ethylene glycol n-butyl ether 15.96.4 8.0Propylene glycol isopropyl ether 15.17.5 13.4Propylene glyco! methyl butyl ether 14.63.6 1.4Propylene glycol methyl ether 15.67.2 13.6Propylene glycol methyl ether acetate 16.16.1 6.6Propylene glycol n-butyl ether 15.65.8 11.2Propylene glycol n-hexyl ether 15.95.8 8.8Propylene glycol n-propyl ether 15.56.3 12.4! Propylene glycol phenyl ether 18.75.7 11.3Propylene glycol t-butyl ether 15.46.8 9.3Propylene oxide 13.58.2 10.5p-Xylene 17.61.0 3.1Pyridine 19.08.8 5.9Quinoline 19.47.0 7.6t-Amyl alcohol (2-methyl-2-butanol) 13.710.0 12.5t-Butyi alcohol (mp 25 °C) 15.25.7 15.2Tetrachloroethylene 19.06.5 2.9Tetraethylene glycol 16.65.7 16.8Tetraglyme {tetraethylene glycol dimethyl ether) 15.8 2.1 8.2Tetrahydrofuran 16.85.7 8.0Tetrahydrofurfuryl alcohol 20.110.3 16.0Tetralin 19.7 2.1 2.9Texanol ester-alcohol* 15.2 6.2 9.8Texasolve h (hexane-heptane mixture)1 15.20.0 0.0Texasolve s-66 (mineral spirits) 15.80.0 0.0Texasolve s-lo (low aromatics/odor mineral spirits) 15.6 0.0 0.0Texasolve v (vm&p naphtha) 15.00.0 0.0Texasolve b (commercial hexane) 15.0 0.0 0.0
Novel Insights into Bioremediation of Petroleum-Polluted Environments and Bacterial Catabolic Pathways
Published in Wael Ahmed Ismail, Jonathan Van Hamme, Hydrocarbon Biotechnology, 2023
Laura Rodríguez-Castro, Roberto E. Durán, Constanza C. Macaya, Flavia Dorochesi, Lisette Hernández, Felipe Salazar-Tapia, Vanessa Ayala-Espinoza, Patricio Santis-Cortés, Ximena Báez-Matus, Michael Seeger
Under anaerobic conditions, aromatic compounds activation occurs by coupling fumarate or carbon dioxide, while nitrate, ferric ion, sulfate or manganese act as the final electron acceptors (Figure 3.5) (Fuentes et al., 2014; Logeshwaran et al., 2018). A general mechanism for anaerobic degradation involves the addition of fumarate to BTEX compounds catalyzed by alkyl and arylalkylsuccinate synthases. Toluene and methyl-substituted monoaromatic HCs degradation via benzylsuccinate synthase depends on activation by fumarate addition (Fuchs et al., 2011; Rabus et al., 2016), except for the p-cymene-degrading Aromatoleum aromaticum pCyN1. Benzylsuccinate synthase catalyzes the reaction between fumarate and the HC substrate, activating the aromatic ring and eventually yielding (R)-benzylsuccinate via a benzyl radical intermediate. (R)-benzylsuccinate is activated to a CoA thioester by a succinyl-CoA dependent CoA-transferase. Benzylsuccinyl-CoA is catabolized to benzoyl-CoA and succinyl-CoA. Interestingly, a phylogenetic analysis of the toluene-activating benzylsuc-cinate synthase (bssA) of the nitrate-reducing bacteria Thauera aromatica K172 revealed that this enzyme is grouped in a cluster with enzymes of sulfate-reducing and iron-reducing bacteria, suggesting that these strains that use nitrate, iron or sulfate as electron acceptors share this metabolic pathway (Rabus et al., 2016). Toluene degradation has been reported in BES under anoxic conditions, showing for the first time the use of toluene as the sole carbon source under nitrate-reducing conditions, removing up to 73% of the pollutant (Espinoza-Tofalos et al., 2018).
Synthesis, characterization, and antimicrobial studies of half-sandwich η6-toluene ruthenium complexes with N,N′-bidentate ligands
Published in Journal of Coordination Chemistry, 2020
Joel M. Gichumbi, Holger B. Friedrich, Bernard Omondi, Hafizah Y. Chenia
Arene-ruthenium complexes play an important role in organometallic chemistry among various metal complexes. They have been shown to exhibit antimicrobial activity against drug-resistant pathogenic microorganism [5, 8, 9]. The increased activity of these ruthenium complexes in antimicrobial, antibiotic, and anticancer applications has greatly contributed to the interest in synthesizing new ruthenium complexes and investigating their possible uses [5, 8, 9]. Although a large number of Ru(II)-arene compounds have been developed and extensively investigated, most studies have focused on [(η6-arene)RuCl(L)Cl]+ (where arene is η6-C6H6, p-cymene, and L the ligand) type complexes [8]. This work therefore is a contribution to half-sandwich ruthenium complexes where arene is η6-C6H5-CH3. Toluene was chosen because it has properties between benzene and p-cymene. This was expected to have an influence on the properties when compared to benzene and p-cymene; due to the presence of one methyl group it has a different ability to provide electron density to the ruthenium metal ion.
Synthesis, characterization and cytotoxic activity of organoruthenium(II)-halido complexes with 5-chloro-1H-benzimidazole-2-carboxylic acid
Published in Journal of Coordination Chemistry, 2019
Darko N. Pantić, Ljiljana E. Mihajlović-Lalić, Sandra Aranđelović, Siniša Radulović, Sanja Grgurić-Šipka
The 1H NMR spectra of all complexes (Supplementary Figures S1–S3) pointed out singlets of the methyl group of p-cymene moiety appeared at 2.17, 2.24, and 2.32 ppm. The signals assigned to the CH proton of the isopropyl group were at 2.71, 2.74, and 2.81 ppm, respectively. The resonances which can be atributed to the two methyl protons of the isopropyl groups are at 1.10, 1.15, and 1.15 ppm. All complexes display the resonances related to protons of the phenyl ring of p-cymene moiety at 5.74–6.13 ppm. The chemical shift of the phenyl ring protons of the benzimidazole moiety are between 7.42 and 8.11 ppm. Furthermore, all complexes display singlets at 14.26, 14.27, and 14.29 ppm attributable to the N-H protons of the 5-chloro-1H-benzimidazole-2-carboxylate ligand.
Experimental study and modeling of the kinetics of gas hydrate formation for acetylene, ethylene, propane and propylene in the presence and absence of SDS
Published in Petroleum Science and Technology, 2019
Hamed Hashemi, Saeideh Babaee, Kaniki Tumba, Amir H. Mohammadi, Paramespri Naidoo, Deresh Ramjugernath
This study is related to the kinetics of ethene (ethylene), ethyne (acetylene), propane and propene (propylene) hydrates. It is the extension of a study, undertaken in the Thermodynamics Research Unit, on the phase equilibrium data of simple and mixed hydrates involving these gases (Tumba et al. 2014; Tumba et al. 2013a; Tumba et al. 2015; Tumba et al. 2013b). The focus in this manuscript is on their kinetic behavior. The four selected hydrocarbons are all important industrial gases. They are generally used as starting material for the production of numerous chemicals. For example, via catalytic dehydrogenation, some established commercial processes allow the conversion of ethane and propane to ethene (ethylene) and propene, respectively (Bhasin et al. 2001). Polyethylene and polypropylene, which are in high demand worldwide, are obtained from the latter two olefins. Furthermore, cumene and cymene are manufactured from benzene and toluene alkylation, respectively, using propene. Propane mainly serves as a refrigerant and a fuel, while ethyne (acetylene) is used to manufacture a wide range of chemicals, as well as used in metalworking (Gannon et al. 2008).