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Preparation of Ultrafine Particles of Metals and Metal Borides in Microemulsions
Published in Promod Kumar, K. L. Mittal, Handbook of Microemulsion Science and Technology, 2018
Tetrahedral complexes of the typeCoBr42- or CoClxBr4-x2-are formed in a micellar solution of the system CTAB-chloroform-water containing Co(II) ions. The maximum in the absorption band is at 719 nm [52]. On the other hand, in pure hexanol, the tetrahedral complex CoCl2Hexanol2 absorbs at 656 nm, and in HBr, CoBr42- absorbs at 710 nm. As in our microemulsions, the tetrahedral complex absorbs at 688 nm, we can assume that it has an intermediate composition, i.e., CoClxBr3−xHexanol− with 0 ≤ x ≤ 3.
Structural Dependence of Intra- and Intermolecular Selectivity in Oxidation with Titanium Silicalites Catalysts
Published in Mike G. Scaros, Michael L. Prunier, Catalysis of Organic Reactions, 2017
Takashi Tatsumi, Makoto Yako, Kazuhira Yanagisawa, Keiko Asano
Similar adsorption phenomena may be important in the oxidation of hydrocarbons. It was found that the yield of oxidation products from hexane on TS-1 leveled off within several hours.3 This is not due to catalyst destruction but due to pore blocking by the products, since the catalytic activity was completely recovered by calcination at 550 °C. Adsorption of hexane on TS-1 was seriously retarded by the presence of 2-hexanol, which was preferentially adsorbed. This suggests that the oxidation products from hexane were rather strongly adsorbed on TS-1, slowing the diffusion of the reactant into the pores.
Surface Properties Characterization by Inverse Gas Chromatography (IGC) Applications
Published in Michel Nardin, Eugène Papirer, Powders and Fibers, 2006
IGC, in food science, is currently used to measure the sorption of water in dry foods205 or the sorption of aroma compounds on food packaging polymers.206 Owing to the dynamic nature of the IGC process, it is also possible to study more complex problems, such as the kinetics and nature of interactions of IGC-chosen solutes with food and/or the starch surfaces. Combined with mass spectrometry (MS), IGC allows to determine the flavor release from a food matrix as a function of water uptake.207 Indeed, the adsorption of water, monitored by IGC, is one cause of the flavor loss (determined by MS). Adsorbed water, from atmosphere, competes with flavor molecules already adsorbed (on buttery-flavored crackers, for instance) that are progressively eliminated. This permits to estimate the onset of the flavor release and the total flavor loss, as well as the nature and order of release. Ducruet et al.208,209 examined the influence of the nature and treatment of starch on aroma retention. They investigated also the influence of humidity on the aromacorn starch interactions. Specific retention volumes (Vg) of selected solutes (1-hexanol, 2-hexanol, octanal, ethyl hexanoate, and d-limonene) were measured. Differences are observed according to the nature (functionality) of the injected solute. H bond formation and dipole–dipole interactions govern the retention mechanism. Moreover, the particular structure of starch, made of amorphous and crystalline zones needs to be taken into account when adsorption occurs in presence of water.
Removal of organics from shale gas fracturing flowback fluid using expanded granular sludge bed and moving bed biofilm reactor
Published in Environmental Technology, 2021
Yu Sun, Liang Huang, Changmiao Lai, Huiqiang Li, Ping Yang
The addition of O and Cl from HOCl contributed to the augment of O-substituted and Cl-substituted compounds (Figure 3(b)). The O-substituted compounds were the dominant heteroatomic compounds in pre-treated FPW, which mainly composed of LMW acids, alcohols, and ester derivatives. LMW acid derivatives contained acetic, heptanoic, propionic, butanoic, pentanoic, hexanoic and sulphurous acid derivatives. Detected alcohols were similar to that of raw FPW, including ethanol, 1-butanol, 2-pentanol, 2-hexanol and cyclohexanol derivatives. The N-substituted compounds decreased by half and the amount of alkyl amine was reduced to three. Nitrile (3-Benzylsulfanyl-3-Fluoro-2-Trifluoromethyl-Acrylonitrile) and alkyl amine (N-Tetrahydrofurfuryl-Pentanamide) was observed in both FPW and pre-treated FPW, which confirmed the existence of refractory substance. Single heterocycle compounds included piperidine derivatives (1,1′-Methylenebis(3-Methylpiperidine)). In addition, unsaturated substances of LMW compounds (hexanes and pentanes) were observed. These observations confirmed the pre-treatment mainly removed high molecule weight compounds and improved biodegradability in the appearance of refractory substance.
Recent developments and potential advancement in the kinetics of catalytic oxidation of glycerol
Published in Chemical Engineering Communications, 2020
Rozaini Abdullah, Syamima Nasrin Mohamed Saleh, Kartina Embong, Ahmad Zuhairi Abdullah
Palladium (Pd) has been one of the most important metals in catalysis (Augustine, 1996). Pd has been widely used as catalysts in various organic syntheses. Blackburn and Schwar (1977) used Pd in the oxidation of secondary alcohol. Pd has also been applied in the hydrogenation of olefins and acetylenes as well as in the hydrogenation of C–C, C–X, C–N, and C–O bonds (Augustine, 1996; Xue and Lin, 2010) and in Heck or Suzuki coupling reaction (Liew et al., 2015; Gong et al., 2016; Seva et al., 2016; Trivedi et al., 2016). Kimura and Tsuto (1993) also reported that Pd was more selective than Pt either in the production of DHA or GLAD under controlled reaction conditions. Further successful studies on the use of Pd oxidation catalysts have also been reported for glycerol (Garcia et al., 1995), α,β-unsaturated alcohols (Giachi et al., 2013), benzyl alcohol (Tan et al. 2012), and 2-hexanol (Mifsud et al., 2010). Recently, Pd had been intensively explored for the production of LA together with other noble metals (Li et al., 2014; Zhao et al., 2014; Marques et al., 2015; Olmos et al., 2016).
Separation of liquid crystalline racemic mixtures obtained on the basis of (R,S)-2-hexanol on amylose tris(3-chloro-5-methylphenylcarbamate) covalently immobilised on silica in high-performance liquid chromatography
Published in Liquid Crystals, 2023
Suitable chiral HPLC separation methods of the racemic mixtures obtained on the basis of (R,S)-2-hexanol were developed. The methods were optimised with respect to the composition of the MP, the flow rate and the type of the elution.