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Abstract  

Salicylaldimine functionalized SBA-15 hybrid mesoporous material was synthesized by post-grafting of salicylaldehyde modified 3-aminopropyltriethoxysilane and followed by introducing Cu(II) ions into the hybrid material via a ligand exchange reaction. The prepared catalyst was characterized by means of XRD, N2 adsorption/desorption, SEM, FT-IR, UV–vis spectroscopy, EPR and XPS techniques as well as ICP-AES and elemental analysis measurements. The solid catalyst was evaluated in the oxidation of styrene with H2O2 as the oxidant under mild conditions, and the reaction parameters (the molar ratio of styrene/H2O2, amount of catalyst, temperatures, solvents, alkaline additive) were investigated and optimized for the oxidation of styrene. The optimal conversion (77.1%) and yield of styrene oxide (60.0%) were obtained at 80 °C using CH3CN as the solvent under basic conditions. Moreover, the covalently anchored Cu(II) salicylaldimine complex showed good recoverability and high stability against leaching of active copper(II) species.

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autoclave equipped with a magnetic stirrer. Styrene carbonate was synthesized by a coupling reaction between styrene oxide (SO) and CO 2 in the presence of ILs, as illustrated in Scheme 2 . In a typical reaction, 0.6 mmol of the IL was introduced into the

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This study investigated the survival and catalytic potential of a single species Pseudomonas taiwanensis VLB120ΔC biofilm for the conversion of styrene to (S)-styrene oxide in a multiphasic capillary microreactor containing the highly toxic substrate styrene as a pure phase. The catalytic biofilm was cultivated under high fluidic stress in a continuous three-phase segmented flow system comprising aqueous medium, air, and styrene. This concept required an adaptation period of 7 days, during which P. taiwanensis VLB120?C developed a biofilm exhibiting a remarkable cellular integrity with nearly 70% intact cells. In a three-phase segmented flow biofilm microreactor, an average specific styrene epoxidation rate of 10 g/Ltube/day was achieved continuously for a period of 20 days without any clogging problems. Overall, this note highlights the robustness of biofilms as a promising biocatalyst format for the conversion/synthesis of toxic organic chemicals and the applicability of multiphasic capillary microreactors for biofilm based catalysis.

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Abstract

The reaction of different types of aromatic and aliphatic epoxides with sodium azide to give vicinal azido alcohols was studied in a microreactor with and without pillars in the channels. Dependent on the substrate, the regioselectivity of the ring opening is affected by the used solvent system, viz. acetonitrile–water (sometimes with 10% acetic acid to promote the reactivity of substrates) or t-butyl acetate–water containing Tween80 as a surfactant. For styrene oxide and α-methylstyrene oxide, the α/ß regioselectivity changes from 4 to 10 and 1.7 to 6.2, respectively, going from acetonitrile–water to Tween80-containing t-butyl acetate–water. The addition of a surfactant (Tween80) stabilizes the interface in the biphasic t-butyl acetate–water. Pillar-containing microreactors gave better conversions than microreactors without pillars and lab scale reactions, probably due to better mixing.

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studied the kinetics of styrene oxidation over supported dodecatungstophosphate and undecaphosphotungstate using 30% aqueous H 2 O 2 as an oxidant. In the present article, we report the kinetic behavior of zirconia supported dodecatungstophosphate

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single-layer surface immobilization of various yeast and bacterial cells [ 34 , 36 , 43 ] and covalently linked enzymes [ 35 , 44 ]. Furthermore, creation of bacterial biofilm used for styrene oxidation [ 45 ], as well as for oriented surface

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of major enantiomers which were determined by comparison with the literature values: for styrene oxide and α-methylstyrene oxide [ 26 ]; for indene oxide, see Palucki et al. [ 27 ] To study the effects of

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