Catalysts For Epoxidation Of Styrene Research Articles

Styrene epoxidation in aqueous over triazine

Epoxies are a popular kind of industrial chemical molecule used as an intermediate in agricultural and medicinal research.Metal-free catalyst for styrene epoxidation was found to be trazine-based microporous polymeric (TMP) network. H2O2 was used as a green oxidant in water as an ecologically friendly medium. The reactions were carried out at room temperature. In 6 hours, the process produced a greater yield of styrene oxide with a 90% conversion and 98% selectivity. Up to four times, the catalytic activity and selectivity of triadzine-based micro porous polymeric networks may be restored and reused.

Co2+-Exchanged flake-like micrometric mica as an efficient solid catalyst for aerobic epoxidation of styrene

Co2+-Exchanged flake-like micrometric mica as an efficient solid catalyst for aerobic epoxidation of styrene

Co supported on interparticle porosity dominated hierarchical porous TS-1 as highly efficient heterogeneous catalyst for epoxidation of styrene

A convenient and easily large-scale production strategy for the synthesis of interparticle porosity dominated hierarchical porous TS-1 (IPD-mesoTS-1) based on sufficiently small TS-1 nanosized crystals was designed and Co nanoparticles were in situ dispersed and deposited on the as-prepared IPD-mesoTS-1 (Co/IPD-mesoTS-1). The catalytic performances for epoxidation of styrene were systematically evaluated. Outstanding catalytic activity has been obtained owing to the highly dispersed Co nanoparticles and the hierarchical porous structure of IPD-mesoTS-1. In addition, the Co concentration, temperature, solvents, oxidants and reaction time also play the important roles in the epoxidation.

Reduced graphene oxide based NiCo layered double hydroxide nanocomposites: An efficient catalyst for epoxidation of styrene

Reduced graphene oxide (RGO) based NiCo layered double hydroxide nanocomposite (NiCo LDH/RGO) was successfully synthesized by simple hydrothermal method. The as-prepared NiCo LDH/RGO5 nanocomposite was used to catalyze the epoxidation of styrene with tert-butyl hydroperoxide (TBHP) as oxidant. The conversion rate of styrene and the selectivity of styrene oxide reaches 95.1% and 73.9%, respectively, proving that NiCo LDH/RGO5 has much better catalytic activity in comparison with other composite catalysts previously reported. Moreover, cycling test shows that the nanocomposite has good catalytic stability.

La/Zn Bimetallic Oxide Catalyst for Epoxidation of Styrene by Cumene Hydroperoxide: Kinetics and Reaction Engineering Aspects

Styrene oxide (STOX) is mostly produced by chlorohydrin process that generates large amount of waste. A greener alternative to the chlorohydrin process is epoxidation of styrene induced by hydroperoxides. In this work, we have studied this reaction using cumene hydroperoxide (CHP) as oxygen inducing reagent under the influence of the prepared La–Zn bimetallic oxides, which offered reasonably high catalytic activity in terms of conversion and high selectivity for styrene oxide. The side reactions can be suppressed by a proper choice of reaction conditions and mode of reaction. At a given reactant conversion, semibatch modes of operation exhibits higher styrene and CHP-based product selectivity when compared with its batch counterpart. Parametric studies are performed to examine the effects of temperature (ambient temperature 363 K), catalyst loading (0.25–1%), CHP-to-styrene mole ratio (∼1–3.5), presence of nonreacting solvent, and surface basicity of catalysts. Catalyst deactivation was studied in detail ...

Palladium nanoparticles supported on UiO-66-NH2 as heterogeneous catalyst for epoxidation of styrene

A series of different amount of Pd nanoparticles were successfully loaded on the metal-organic frameworks UiO-66-NH2 using a simple solution impregnation method and applied as efficient catalysts for epoxidation of styrene. In this work, the best reaction efficiency can be explored by altering Pd loadings of Pd/UiO-66-NH2, solvents, reaction temperatures and the molar ratios of styrene to tert-butyl hydroperoxide. Interestingly, when Pd loadings of Pd/UiO-66-NH2 is 3.69 wt%, the target product can be obtained in high yield and selectivity.

Copper-cobalt Bimetallic Oxides-doped Alumina Hollow Spheres: A Highly Efficient Catalyst for Epoxidation of Styrene

Copper-cobalt bimetallic oxides-doped alumina hollow spheres(CuCo/AHS) were fabricated through the sacrificial carbonaceous template strategy. The dependence of the physicochemical properties and morphologies of CuCo/AHS on the composition of copper and cobalt in CuxCoy/AHS(x/y=9/1, 7/3, 5/5, and 3/7) were characterized by X-ray powder diffraction, nitrogen physisorption, atomic adsorption spectroscopy, scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. Among these catalysts, Cu7Co3/AHS catalyst exhibited perfect hollow sphere structure, thin wall, and big pore size. The calcined catalysts were examined for the epoxidation of styrene with tert-butyl hydroperoxide as oxidant. Compared with the monometallic counter-parts(Cu/AHS and Co/AHS) and other CuxCoy/AHS catalysts, Cu7Co3/AHS catalyst showed higher performance, yielding a styrene conversion of 64.6% with 93.0% selectivity toward styrene oxide. In addition, the strong interaction of Cu2+ or Co2+ with AHS ensured the good stability after four consecutive reactions.

Barium Hexaferrite (BaFe12O19) Nanoparticles as Highly Active and Magnetically Recoverable Catalyst for Selective Epoxidation of Styrene to Styrene Oxide.

Herein, we are reporting the use of pure single phase barium hexaferrite (BaFe12O19) nanoparticles as an efficient catalyst for epoxidation of styrene. BaFe12O19 nanocatalysts exhibit high conversion of styrene with excellent selectivity of styrene oxide formation. Easy method of preparation, capability of catalyzing the epoxide reaction of styrene to styrene oxide with excellent styrene conversion (~91%) and high styrene oxide selectivity (~86.5%), easy magnetic separation and very good reusability make the synthesized BaFe12O19 nanocatalyst an excellent catalyst for this reaction. To the best of our knowledge, this is the first time the use of BaFe12O19 as catalyst for this reaction has been reported.

Synthesis of Nickel Lysine Salen Complex and Its Catalytic Performance for Styrene Epoxidation

Nickel lysine salen complex was successfully synthesized via a stepwise procedure and applied as a heterogeneous catalyst for styrene epoxidation. For comparison, several other transition metal (Mn, Fe, Co, and Cu) lysine salen complexes were also synthesized. The prepared catalysts were characterized by Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX). Data obtained by FT-IR and Raman spectroscopy indicated the formation of C=N bonds and the complexation of these bonds with metal ions. SEM analysis revealed that the complexation of metal ions with the C=N involves the change in surface morphology of samples. In addition, atomic percent composition of samples was obtained from EDX spectra, which was the complementary evidence for the formation of complexes. Results of catalytic measurements showed that a high conversion of styrene (91.51%) and selectivity to styrene oxide (91.99%) could be achieved over the nickel lysine salen complex with tert-butyl hydroperoxide as the oxidant. When the catalyst was reused the conversion of styrene decreased but the selectivity to styrene oxide still remained high.

Synthesis of Efficient Ce Modified CuO/CoAl-HT Catalysts for Styrene Epoxidation

The controllable synthesis of efficient supported non-noble with fitting chemical state for styrene epoxidation is of great significance to save scarce resources and improve the atom economy. Herein, a series of Ce modified CuO/CoAl-hydrotalcite catalysts was prepared using deposition–precipitation (DP) method. The appropriate addition of Ce (Ce/Cu = 0.2) could contribute to the dispersion of CuO on the surface of support. Moreover, the chemical state of CuO could be finely tuned by the introduction of Ce additives: Ce interacted with CuO and maked CuO surface enrichment of electrons, while CeO2 weakened the interaction between CuO and CoAl-HT support, increasing the percentage of Cu2+ ions (CuA2+) in metal oxides. Therefore, the obtained CuO–0.2CeO2/CoAl-HT catalyst, possessing maximum CuA2+, exhibited optimal styrene oxide yield in styrene epoxidation reaction at similar condition to date, achieving 79.5% selectivity at 99.6% styrene conversion.

Graphene Oxide Nano-Sheets-Supported Co(II)-d-Penicillamine as a Green and Highly Selective Catalyst for Epoxidation of Styrene

A new efficient heterogeneous catalyst was introduced for the epoxidation of styrene. The catalyst was obtained from functionalization of graphene oxide nano-sheets with d-penicillamine, and then complexation of graphene oxide functionalized d-penicillamine with Co(II). High yield and excellent selectivity were achieved for the epoxidation of styrene using the synthesized catalyst in solvent-free conditions at 50 °C using H2O2 as a green oxidant during 2 h. The reaction has some advantages such as solvent-free and mild reaction conditions, high yield, excellent selectivity, green oxidant and short reaction conditions. Also, the recovered catalyst is applicable for 6 times without decrease in yield.

Mesoporous TS‐1 Nanocrystals as Low Cost and High Performance Catalysts for Epoxidation of Styrene

AbstractMesoporous TS‐1 nanocrystals were facilely synthesized without involving additional templates. The usage of inorganic silicon source, less structure‐directing agent and high yields of nearly 100% made this template‐free strategy suitable for large‐scale synthesis with low cost. Furthermore, the as synthesized TS‐1 exhibited comparable epoxidation performance than those obtained by other methods.

Gold nanoparticles supported on cellulose aerogel as a new efficient catalyst for epoxidation of styrene

A new efficient heterogeneous catalyst was introduced for the epoxidation of styrene. The catalyst was obtained from deposition of gold nanoparticles on the cellulose aerogel. The catalyst was characterized with XRD, TGA, EDX, BET, FAAS and SEM. High yield and excellent selectivity were achieved for the epoxidation of styrene in solvent-free conditions at room temperature using H2O2 as a green oxidant during 1 h. The reaction has some advantages such as solvent-free and mild reaction conditions, low catalyst loading, high yield, excellent selectivity, green oxidant and short reaction duration. In addition, the catalyst is recyclable and applicable for six times without decrease in yield.

Pd(II) anchored to modified Fe3O4 nanoparticles as a new magnetically recoverable catalyst for epoxidation of styrene

A new support for Pd(II) was synthesized via the functionalization of Fe3O4 nanoparticles with N-(2-aminoethyl)acetamide. PdCl2 was anchored to the support for obtaining a heterogeneous magnetically recoverable catalyst for Pd(II). High yield and excellent selectivity were obtained for the green epoxidation of styrene derivatives using H2O2 as a green oxidant in H2O as the solvent at 100 °C. Also, the recovered catalyst is applicable for four times without significant decrease in yield.

Synthesis of Ag Porous Carbon Nanofiber by Electrospinning and Their Use as Catalyst for Styrene Epoxidation

A simple method to prepare the Ag porous carbon nanofiber is reported. Ag porous carbon nanofiber was prepared by electrospinning and high temperature calcination. In this process, AgNO3-PMMA/PAN solution was the precursor solution of electrospinning, and Ag nanoparticles and pores were made by high temperature calcination. The catalytic activity of the Ag porous carbon nanofibers was confirmed by the styrene epoxidation. In the catalytic process, the conversation of styrene was 71% and the selectivity of styrene oxide was 83%.

Modified Ti/MCM-41 catalysts for enantioselective epoxidation of styrene

Ti sites grafted on MCM-41, pretreated at different temperatures, have been modified with chiral tartrates, leading to different species. Those solids are active catalyst for the epoxidation of styrene with tert-butyl hydroperoxide, although their efficiency is not optimal, mainly due to the subsequent epoxide rearrangement to phenyl acetaldehyde and further oxidation of it. Styrene oxide is obtained with moderate enantioselectivity, in the range of 55–62% e.e., and the best overall results correspond to the use of MCM-41 calcined at the lowest temperature (550°C). These results are much better with regard to styrene oxide selectivity than those obtained in homogeneous phase under the same conditions, whereas enantioselectivity is similar. The heterogeneous catalysts are recoverable, but only partially due to a loss in activity, although enantioselectivity is kept at similar levels, demonstrating the stability of the supported Ti-tartrate species.

Aminopropyl group-modified SBA-15 covalent attachment Mn(salen) complexes as catalysts for styrene epoxidation

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Gold nanoparticles supported on nanoscale amine-functionalized MIL-101(Cr) as a highly active catalyst for epoxidation of styrene

Gold nanoparticles can effectively be incorporated on to the matrix of NH2-MIL-101(Cr) by a facile solution approach. The resulting nanocatalyst acts as efficient heterogeneous catalyst for epoxidation of styrene.

Enantioselective Epoxidation of Styrene by Manganese Chiral Schiff Base Complexes Immobilized on MCM-41.

Two chiral MnIII complexes synthesized and characterized by single-crystal X-ray diffraction were grafted onto mesoporous silica MCM-41. The MCM-41-immobilized solid chiral catalysts were characterized by various spectrochemical and physicochemical methods (XRD, FTIR, 29 Si NMR, TGA, UV/Vis/DRS, EPR, cyclic voltammetry, SEM, BET). Both the homogeneous and heterogeneous MnIII chiral complexes are found to be effective catalysts for epoxidation of styrene. MCM-41-supported chiral catalysts are found to retain their catalytic activity up to five cycles. When an ionic liquid was implemented to enhance the catalytic recyclability of the homogeneous catalysts, they can be recycled up to three times. However, after the third cycle the catalytic activities of the complexes were found to decrease due to rupturing of the chiral catalyst.

Prussian blue analogues as heterogeneous catalysts for epoxidation of styrene

Prussian blue analogues are high performance catalyst for low toxicity, lower dosage reactions, simple preparation processes and cheap.