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An efficient biocatalytic approach for enantio‐ and regioselective ring‐opening of styrene oxides with cyanate was developed by using the halohydrin dehalogenase HheC from Agrobacterium radiobacter AD1, generating the corresponding chiral 5‐aryl‐2‐oxazolidinones in up to 47% yield and 90% ee. Additionally, the origin of enantioselectivity and regioselectivity of the HheC‐catalyzed cyanate‐mediated ring‐opening process was uncovered by single enantiomer bioconversions and molecular docking study. [ABSTRACT FROM AUTHOR]

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In the present study, the cobalt (II) complex [Co-HMBED] has been prepared and characterized by spectrochemical techniques, which confirmed its square planar structure. The catalytic activity of the cobalt complex was evaluated towards solvent-free conversion of CO2 and styrene oxide into cyclic styrene carbonate and polymerization of lactide. This perspective describes the synthesis, characterization and catalytic studies of Co-HMBED complex; towards coupling of styrene oxide and CO2 to produce cyclic styrene carbonates and polymerization of lactide. [ABSTRACT FROM AUTHOR]

Mesoporous titanium silica-coated cobalt ferrite core-shell structures were synthesized as catalysts for styrene oxidation by hydrothermal and sol-gel methods. The catalysts were characterized by XRD, AA, SEM, TEM, FTIR spectroscopy, N 2 physisorption, ICP-OES and XPS. XRD patterns indicated that the magnetic core was composed of cobalt ferrite. SEM and TEM micrographs along with the IR spectra confirmed the presence as desired of a dense SiO 2 layer on the core. XPS revealed that the outest layer of the structure was made of a mesoporous Ti-SiO 2 layer. The successful incorporation of Ti active oxidation sites (framework Ti, FW Ti) in the mesoporous layer was verified by XPS Ti 2p spectra decomposition. The post-grafting method for the Ti insertion proved to be better than the one-pot to obtain a higher number of active Ti sites on the surface. All the synthesized catalysts were active in styrene oxidation with dilute aqueous H 2 O 2. The highest styrene conversion (37%) was obtained with the catalyst synthesized by post-grafting of Ti on a preformed mesoporous SiO 2 layer with a high specific surface area. This catalyst was the one with the highest fraction of surface FW Ti (XPS). The major products of the reaction were benzaldehyde and phenyl acetaldehyde. The catalyst was easily recovered from the reaction medium using an external magnet, and no significant loss of activity was observed after four catalytic cycles. [Display omitted] ● Successful synthesis of core-shell catalysts by hydrothermal and sol-gel methods. ● Titanium was inserted in the mesoporous layer mainly as isolated framework Ti. ● Ti-SiO 2 @CF and Ti/SiO 2 @CF catalysts are active in styrene oxidation. ● Benzaldehyde and phenyl acetaldehyde are the main oxidation products. ● Easy recovery of Ti/SiO 2 @CF from the reaction medium due to magnetic properties. [ABSTRACT FROM AUTHOR]

One dimensional silica-based nanotubes represent an innovative and promising morphology in the context of heterogeneous catalysis. Here these nanostructures were prepared for the first time as bifunctional materials, with hafnium or tin atoms inserted as single sites in the silica structure and imidazolium moieties anchored at the surface. The low dimensional solids thus present both acid sites owing to the presence of metal cations in tetrahedral coordination (co-catalyst) and nucleophilic species coming from the counterion of the imidazolium moieties (catalyst). The design of the catalysts consisted of two main steps. The Hf- or Sn-doped silica solids were initially prepared using a straightforward sol-gel method including a pH adjustment step allowing a quantitative insertion of the metal cations in the silica framework. These materials were post-functionalized with imidazolium moieties. The solids were extensively characterized thus confirming the presence of well-defined and open tubular structure, high specific surface area, successful insertion of Hf and Sn in the silica framework, and a correct functionalization with imidazolium salts. The different catalysts were tested in the valorization of CO 2 with styrene oxide to give the corresponding cyclic carbonate. The bifunctional solids were stable and recyclable. The versatility of the best catalyst, represented by the Hf-based material, was confirmed using different epoxides. Finally, by tuning the reaction conditions or changing the imidazolium salt, a further boost of the catalytic performances was achieved. [Display omitted] • A series of novel 1D silica-based nanotubes were prepared for the first time as bifunctional catalysts. • A synergistic activation enhancing the overall catalytic performances was disclosed. • The structure-activity correlation allows highlighting the combined effect of Brønsted and Lewis acid sites. • Hf-doped SiO 2 nanotubes were particularly efficient for the synthesis of glycidol carbonate. • The novel structures were highly active and versatile in CO 2 conversion, stable and reusable. [ABSTRACT FROM AUTHOR]

In CO 2 cycloaddition reactions with epoxides that have bulky or long-chain substituents, the yield significantly decreases when using heterogeneous catalysts, including MOFs, with micropores smaller than 14 Å. In this study, a new MOF material called Zn-URJC-13 is reported. This MOF combines different features such as that it contains acid and basic Lewis sites based on Zn and -NH 2 groups, exhibits permanent porosity with a bimodal porous system centered at 11 and 17 Å suitable for the diffusion of cycloaddition reaction species, and it is chemically stable in various common organic solvents. The aim of this material is to improve the textural properties of other MOFs with similar chemical compositions, making it suitable as a catalyst for CO 2 cycloaddition reactions with epoxides even bulky. This novel material exhibits high affinity to CO 2 molecules, with a Q st of 62 kJ/mol. The Zn-URJC-13 catalyst demonstrates efficient performance in CO 2 cycloaddition reactions using a wide range of epoxides, including those with long-chain and bulky substituents such as allyl glycidyl ether and styrene oxide. It can achieve an epoxide conversion as high as 84 % and selectivity to carbonate products above 90 % for the bulkiest styrene oxide. When compared to other Zn-based MOF materials with similar or different structures but without amino groups, the new material exhibits superior catalytic performance. Furthermore, Zn-URJC-13 can be reused in five consecutive reaction cycles while maintaining its efficient catalytic behavior and crystalline structure. These findings highlight the notable potential of Zn-URJC-13 for CO 2 cycloaddition transformation routes. [Display omitted] • Zn-URJC-13 is a novel MOF structure with acid and basic Lewis sites from Zn and -NH2. • Zn-URJC-13 exhibits a bimodal pore distribution centered at 11 and 17 Å. • Zn-URJC-13 exhibits a high affinity to CO2 with a heat of adsorption of 62 kJ/mol. • Zn-URJC-13 is an efficient catalyst for CO2 cycloaddition with epoxides even bulky. • Zn-URJC-13 is stable, at least, in five consecutive cycles of CO2 cycloaddition. [ABSTRACT FROM AUTHOR]

[Display omitted] • Atom-economic transformation of CO 2 and epoxides to cyclic carbonates. • Construction of metal-free activated carbon supported ionic liquid (AC-ILs). • Investigation on role of different anions Br-, BF 4 −, NTf 2 − and HSO 4 − in AC-ILs. • 100 % conversion obtained at 120 °C, 20 bar CO 2 , 13 h under solvent-free conditions. • Retention in catalytic performance for six repetitive recycles. The use of ionic liquids (ILs) based materials in catalysis, especially for CO 2 conversion has been attracted great scientific attention due to green catalytic approach and eco-friendliness of the material. In this effort, especially engineered NH 2 -functionalized imidazolium based ILs with different anions were prepared to develop new covalent ILs functionalized activated carbon (AC) catalysts. All different AC-ILs namely AC-IL-Br, AC-IL-BF 4 , AC-IL-NTf 2 and AC-IL-HSO 4 was successfully synthesized by metathesis reaction, and characterized using various analytical and spectroscopic techniques. With the maximum immobilization of the NH 2 -functionalized ILs on the AC support, the immobilized AC-ILs showed superior structural advantages such as high thermal stability and appreciable surface area. The newly developed AC-ILs as bi-functional catalysts were applied in the fixation of CO 2 into epoxide and it displayed high catalytic activity during the catalytic screening. Various reaction variables were surveyed wherein especially, 10.0 wt% of AC-IL-NTf 2 catalyst demonstrated the best catalytic activity with 100 % conversion of styrene oxide and 83 % selectivity towards styrene carbonate at 120 °C, 20 bar CO 2 pressure in 13 h under solvent-free conditions. The enhanced performance by AC-IL-NTf 2 catalyst was achieved as a result of least co-ordination of the NTf 2 − anion with the NH 2 -functionalized imidazolium cation which helped in the opening and stabilization of epoxide ring and increased the reaction rate. The best performing AC-IL-NTf 2 catalyst was found to be compatible with a broad substrate scope and could effectively produce the respective cyclic carbonates in good to quantitative yields with different substituted epoxides. Most significantly, AC-IL-NTf 2 catalyst could be easily separated from the reaction mixture and recycled it for number of cycles. It maintained its catalytic activity without any evident leaching and structural damage up to six recycles. Additionally, plausible reaction mechanism also has been proposed with AC-IL-NTf 2 catalyst with the help of catalytic activity results and characterization support. [ABSTRACT FROM AUTHOR]

Herein, we report a low-metal iron-supported (0.06 wt%) catalyst (Fe20/NC-Mg), in which the FeN x site and Mg(OH) 2 nanorods are synergistic to achieve the efficient synthesis of quinoxaline (16 examples, 82–91 % yield) with water as a solvent and without additional bases. Moreover, the industrial application potential of Fe20/NC-Mg is demonstrated by gram-level synthesis and reusability of catalysts after four cycles. This protocol has high atomic and step economy, which meets with the requirement of green synthesis. [Display omitted] [ABSTRACT FROM AUTHOR]

A method for the synthesis of 2-(2-(dialkylamino)ethylamino)ethanols based on the epoxide ring opening in styrene oxide by N,N-disubstituted ethylenediamines was developed. It is shown that the opening of the oxirane ring by diamines in 2-propanol at room temperature occurs mainly according to the Krasusky rule at the bond between the oxygen atom and the less substituted carbon atom. A mixture of two products with the predominance of the secondary diamino alcohol up to 82% was obtained. It was found that the separation of the products by distillation or recrystallization does not allow obtaining pure isomers. The mixture of isomers was converted into dihydrochlorides by dry HCl in dioxane and diethyl ether. Pure 2-(2-(dialkylamino)ethylamino)-1-phenylethanols and 2-(2-(dialkylamino)ethylamino)-2-phenylethanols were separated by the first fractional recrystallization of a mixture of diaminoalcohol dihydrochlorides from a mixed solvent followed by alkalization of the products with an aqueous sodium hydroxide solution. The diamino alcohols were characterized by FT-IR, 1H- and 13C-NMR and HRMS-ESI.

Under optimized reaction conditions, the 2 h Cu-Al catalyst, which was prepared at a constant temperature of 70 °C, a pH of 9 and an aging time of 2 h, provided a 98% yield of 5-(acetoxymethyl)-2-furanmethanol. Copper-based catalysts are very active in a wide range of different reactions, such as methanol synthesis, steam reforming/WGS, hydrogenation/dehydrogenation/transfer hydrogenation, oxidation, dehydrogenative coupling, acid-base reactions, etc. References 1 Bukhtiyarova M.V., Bulavchenko O.A., Bukhtiyarov A.V., Nuzhdin A.L., Bukhtiyarova G.A. Selective Hydrogenation of 5-Acetoxymethylfurfural over Cu-Based Catalysts in a Flow Reactor: Effect of Cu-Al Layered Double Hydroxides Synthesis Conditions on Catalytic Properties. [Extracted from the article]

We describe the use of titanocene monochloride in the implementation of an experimental procedure that enables control of the homolytic opening of styrene oxides in a chemoselectively controlled manner. This leads either to homocoupling products or to phenethyl alcohol derivatives. The process occurs via the generation of benzyl radicals, which may undergo a) recombination or b) reduction, yielding benzyl‐Ti(IV) species upon subsequent addition of H2O to the corresponding hydroxylated compounds. The main goal of this work is the study of the reactivity pattern of styrene oxides towards the formation of the mentioned products, thereby adding value to this interesting building block. [ABSTRACT FROM AUTHOR]

We report the syntheses and structural characterization of a Zn(II) metallacycle [Zn2{(L)2(DMF)2(NO3)2}]·(NO3)2 (1) along with a Cd(II) coordination polymer [{Cd1(L)2(DMF)2}·(NO3)2]n (2) (where L = N,N′-bis-(3-pyridyl)terephthalamide; DMF = dimethylformamide) and their utilization as fluorescent probes for highly selective recognition (turn-off) of Fe3+ and CrO42− ions. Compounds 1 and 2 were prepared by utilizing ligand L and the nitrate salt of zinc and cadmium, respectively. Single crystal X-ray analysis reveals that 1 adopts an overall Zn(II) metallacycle architecture, whereas 2 displays a one-dimensional (1D) polymeric structure. Both 1 and 2 showed high fluorescence stability in aqueous solution and selectively detected Fe3+ and CrO42− ions with high quenching constants and low detection limits of 2.34 × 106 M−1 and 0.153 μM for Fe3+, 6.72 × 105 and 0.205 μM for CrO42− (for 1); 3.25 × 106 and 0.193 μM for Fe3+, 6.94 × 105 and 0.155 μM for CrO42− (for 2). Notably, ligand L itself did not display any type of recognition for any ions in DMF as well as in aqueous media. Moreover, 1 and 2 were also employed as heterogeneous catalysts for the ring-opening reaction (ROR) of epoxides with various assorted amines and up to 95% yield (TON, 47.5 and TOF, 11.9 h−1) was observed with perfect regioselectivity in the case of styrene oxide. [ABSTRACT FROM AUTHOR]

A heterogeneous palladium(II) catalyst anchored to modified metal-organic framework has been synthesized and characterized. The performance of the catalyst has been tested for the hydrogenation of styrene oxide at ambient temperature and pressure. The catalyst showed an excellent activity and selectivity for the preparation of 2-phenylethanol from styrene oxide with 100% conversion and 98% selectivity. The catalyst is very stable and easily recyclable for several times without loss of activity. [ABSTRACT FROM AUTHOR]

Several new random copolyethers of styrene oxide (SO) and other monosubstituted oxirane as comonomer, i.e., propylene oxide (PO), isopropyl glycidyl ether (IPGE) or allyl glycidyl ether (AGE), were synthesized in THF solution at room temperature. As initiator monopotassium salt of dipropylene glycol activated by 18-crown-6 complexing agent was used. Synthesized copolyether-diols were characterized by SEC, 13C NMR and MALDI-TOF techniques. They were unimodal and had Mn = 3500–4600 and relatively low dispersity (Mw/Mn = 1.16–1.18). Low unsaturation of the products resulted from chain transfer reaction to styrene oxide. Composition of SO/PO-diol, SO/IPGE-diol and SO/AGE-diol copolymers was determined by MALDI-TOF mass spectrometry. Homopolymers were not formed during the processes. [ABSTRACT FROM AUTHOR]

Pd(II) ions were introduced into Mg0.7Al0.3(OH)2(CO3)0.15·mH2O through the co-precipitation of the corresponding nitrate salts at a constant pH value. The presence of Pd in the brucite-like layers affects an increased surface area and decreased crystal domain of the Mg–Al hydrotalcite catalysts. Pd(II) ions may exist in both intra- and extra- brucite-like layers and exhibit different roles in the oxidation of styrene with t-BuOOH, depending on the amount of palladium. The insertion of Pd(II) into the hydrotalcite lattice has significantly improved the catalyst stability. The highest conversion of styrene is about 80% for the production of styrene oxide and benzaldehyde at low temperatures. [ABSTRACT FROM AUTHOR]

Zinc bromide was immobilized in the framework of graphite carbon nitride (Zn-CN) and loaded on the surface of carbon fibers to obtain the catalyst Zn-CN/C which was used in the synthesis of styrene carbonate from coupling reaction between styrene oxide and carbon dioxide. • The simplest and most common heterogeneous material carbon fibers were used as the carrier of the catalyst. • The preparation process of the catalyst was simple and low cost as well as could be mass-produced. • The catalyst had a good catalytic effect on the cycloaddition CO 2 with styrene oxide. Chemically fixing CO 2 into the fine chemicals is a sustainable route to the utilization of CO 2 and meets the requirements of green chemistry. Generally, an important intermediate, high-valued cyclic carbonates, is produced by catalyzed cycloaddition of CO 2 with epoxides during the CO 2 fixation. However, most of the catalysts for cycloaddition can hardly meet the standards of the green chemistry, including highly efficient, low cost, easily recoverable and recyclable etc. Therefore, in this work, an environmentally friendly composite Zn-CN/C catalyst for the cycloaddition of styrene oxide and CO 2 was successfully prepared by a facile method. To this end, zinc bromide was immobilized by graphitic carbon nitride (gCN) and then supported on carbon fibers. Meanwhile, the crystal structure, types of chemical bonding, surface morphologies, and electronic transmission of the prepared catalyst were also investigated. Furthermore, the catalytic performance was evaluated by the cycloaddition reactions of styrene oxide and CO 2 , a satisfactory result of the moderate yield of 50–90% with a good selectivity (>99%) was obtained. Finally, a credible mechanism of the reaction was proposed. [ABSTRACT FROM AUTHOR]

The base-free styrene epoxidation with H2O2 as an oxidant was strongly in accordance with the requirements for a sustainable chemical industry. Aiming at the low efficiency of a non-noble metal catalyst system, we proposed utilizing the synergistic effect and manipulating the surface acid–basic property of materials to increase the catalytic performance in this reaction. Herein, to combine two promoting approaches, we synthesized a series of mixed metal oxide (MMO) materials to screen promising active components with a suitable acid–basic property for H2O2–styrene epoxidation. As a result, the highest styrene conversion (82.8%) and best styrene oxide selectivity (79.7%) were achieved over a CuCr-MMO catalyst. The catalytic performance was considerably enhanced compared with the CuO and CrOx references. Detailed characterizations were performed to investigate the dispersion, electronic structure, and acid–basic property to explain the structure–performance relationship. On one hand, the promoted dispersion of the Cu and Cr components contributed to more catalytic sites and the electron transfer between Cu and Cr improved the intrinsic activity, which were both responsible for the enhanced activity. On the other hand, the unique structure modulated the acid–basic properties to be suitable for this catalytic system. In particular, a suitable basicity was facilitated to selectively transform H2O2 into HOO˙ radicals, while a low acidity suppressed the epoxide ring opening to form phenylacetaldehyde. By combining the high accessibility, suitable basic–acid property, and fast electron transfer, CuCr-MMO exhibited a high styrene conversion and selectivity to styrene oxide. [ABSTRACT FROM AUTHOR]

Epoxidation of styrene under heterogeneous catalyzed conditions provides environmentally friendly routes to produce styrene oxide, an important synthetic intermediate for synthesis of perfumes, epoxy resins, plasticizers, drugs, sweeteners and fine chemicals. The present review explores epoxidation of styrene under heterogeneous catalysed conditions using a variety of catalysts such as metal nanoparticles, metal oxides (of group 12 and 13 metals, transition metals, rare earth metals), transition metals and complexes, polyoxometallates, microporous and mesoporous materials (zeolites, modified zeolites, organic/inorganic porous hybrid materials, porous metal oxides, SBA 15) and polymers using hydrogen peroxide (H2O2), tert‐butyl hydroperoxide (TBHP), air or oxygen as oxidants.The use of salen based transition metal complexes and of chiral porphyrins as catalysts in asymmetric epoxidation of styrene is also reviewed. The reaction mechanism studies of most of these reactions suggest an intermediate formation of a reactive metal‐oxygen species, by interactions between the catalyst and oxidant. [ABSTRACT FROM AUTHOR]

A biocatalytic approach towards a range of 4‐aryloxazolidinones is developed using a halohydrin dehalogenase from Ilumatobacter coccineus (HheG) as biocatalyst. The method is based on the HheG‐catalyzed α‐position regioselective ring‐opening of styrene oxide derivatives with cyanate as a nucleophile, producing the corresponding 4‐aryloxazolidinones in moderate to good yields. Synthesis of enantiopure 4‐aryloxazolidinones is also achievable using chiral epoxide materials. [ABSTRACT FROM AUTHOR]

New epoxides, derivatives of pyridine, 2,2′-bipyridine, and 1,10-phenanthroline, were synthesized from the respective α-methylazaarenes. The obtained racemic 2-oxiranyl-azaarenes along with styrene oxide and trans-stilbene oxide were submitted to the ring opening with chiral primary amines as a chiral auxiliary. The most effective reaction was run in the presence of Sc(OTf)3/diisopropylethylamine for 7 days at 80°C, affording a good yield of the amino alcohols. Except for styrene oxide which gave both α- and β-amino alcohols, the reactions led regioselectively to the corresponding diastereomeric β-amino alcohols. The resulting diastereomers were separated, and the configurations of their stereogenic centers were established. The obtained enantiomerically pure 2-pyridinyl- and 6-(2,2′-bipyridinyl)-β-amino alcohols were tentatively tested as chiral ligands in the zinc-catalyzed aldol reaction. [ABSTRACT FROM AUTHOR]

• Uniform magnetically separable CoFe 2 O 4 nanoparticles were facilely developed. • The catalyst is efficient and robust for the selective epoxidation of styrene. • Bimetallic CoFe 2 O 4 outperformed its monometallic counterparts Co 3 O 4 and Fe 2 O 3. Developing catalysts with unique compositional and structural characteristics, high cost-efficiency, and preferable catalytic performance are still an ongoing task for the selective oxidation of alkenes. Herein, we report the facile construction of uniform magnetically separable CoFe 2 O 4 nanoparticles, which can function as an efficient and robust catalyst for the selective epoxidation of styrene with tert-butyl hydroperoxide as the oxidant. This bimetallic catalyst significantly outperformed its monometallic counterparts with respect to Co 3 O 4 flakes and Fe 2 O 3 rods both in terms of total activity and epoxide production. In the presence of CoFe 2 O 4 nanoparticles as the catalyst, the yield of styrene oxide (SO) can achieve 79.7% with a total styrene conversion of 96.4% and a selectivity of 82.7% to SO under the optimal reaction condition. In addition, the activation energy was measured, and a plausible reaction mechanism was proposed. The outstanding catalytic performance of the CoFe 2 O 4 catalyst can be ascribed to the synergistic effects regarding the abundant surface metal redox couples induced by the bimetallic nature and the mesoporous structure with high surface area. [ABSTRACT FROM AUTHOR]

Phase-pure interpenetrated MOF-5 ([Zn4(O)(BDC)3]) was synthesized by pH* control in a reaction medium, and its stability in the presence of epoxides was confirmed by powder X-ray diffraction analysis. Interpenetrated MOF-5/tetra-n-butylammonium bromide (int-MOF-5/n-Bu4NBr) showed a high catalytic activity toward CO2 fixation to epoxide to synthesize cyclic carbonates. The conversions of propylene oxide (PO) and styrene oxide (SO) by int-MOF-5/n-Bu4NBr were almost two times higher than those by MOF-5/n-Bu4NBr under the same conditions. From a kinetics point of view, the coupling reaction rate of PO and CO2 was much higher than that of SO and CO2, which may be due to steric effects. The optimized geometries by the density functional theory calculation revealed that Lewis acidic Zn(II) sites of tetranuclear {Zn4O} clusters can work as the catalytic center to bind epoxides to open the rings by a nucleophilic attack. This co-catalyst system may be useful for the synthesis of cyclic carbonate by CO2 fixation. [ABSTRACT FROM AUTHOR]

A series of 5,10,15,20‐tetrakis(2,3‐dichlorophenyl)porphyrinate complexes of manganese(III) [MnIII(T2,3DCPP)X] with six different axial ligands (X=NO3−, AcO−, IO3−, Br−, Cl−, HO−) were investigated as catalysts in the cycloaddition reactions of CO2 and styrene oxide (SO), under mild conditions, i. e. atmospheric pressure and 60 °C. [MnIIIT(2,3DCPP)IO3] showed the best catalytic performance, selectively producing the respective cyclic carbonate from diverse epoxides using tetrabutylammonium bromide as a nucleophile source. Mechanistic considerations were inferred from electronic spectra and spectrophotometric titrations, showing that there are a series of equilibriums involved in the formation of the catalytic active species. Stability constants for the proposed equilibrium models were determined using SQUAD software. A catalytic cycle has been proposed based on those observations. [ABSTRACT FROM AUTHOR]

The role of water as highly effective hydrogen‐bond donor (HBD) for promoting the coupling reaction of CO2 with a variety of epoxides was demonstrated under very mild conditions (25–60 °C, 2–10 bar CO2). Water led to a dramatic increase in the cyclic carbonate yield when employed in combination with tetrabutylammonium iodide (Bu4NI) whereas it had a detrimental effect with the corresponding bromide and chloride salts. The efficiency of water in promoting the activity of the organic halide was compared with three state‐of‐the‐art hydrogen bond donors, that is, phenol, gallic acid and ascorbic acid. Although water required higher molar loadings compared to these organic hydrogen‐bond donors to achieve a similar degree of conversion of CO2 and styrene oxide into the corresponding cyclic carbonate under the same, mild reaction conditions, its environmental friendliness and much lower cost make it a very attractive alternative as hydrogen‐bond donor. The effect of different parameters such as the amount of water, CO2 pressure, reaction temperature, and nature of the organic halide used as catalyst was investigated by using a high‐throughput reactor unit. The highest catalytic activity was achieved with either Bu4NI or bis(triphenylphosphine)iminium iodide (PPNI): with both systems, the cyclic carbonate yield at 45 °C with different epoxide substrates could be increased by a factor of two or more by adding water as a promoter, retaining high selectivity. Water was an effective hydrogen‐bond donor even at room temperature, allowing to reach 85 % conversion of propylene oxide with full selectivity towards propylene carbonate in combination with Bu4NI (3 mol %). For the conversion of epoxides in which PPNI is poorly soluble, the addition of a cyclic carbonate as solvent allowed the formation of a homogeneous solution, leading to enhanced product yield. [ABSTRACT FROM AUTHOR]

(R)‐Phenylglycinol is an important chiral building block for pharmaceutical and fine chemical industry, and its efficient synthesis from cheap and commercially available starting materials is challenging and highly desirable. Herein, a new three‐step one‐pot cascade system employing epoxide hydrolase, glycerol dehydrogenase, and ω‐transaminase was designed for the asymmetric synthesis of (R)‐phenylglycinol from racemic styrene oxide. A cofactor self‐sufficient system employing AlaDH/L−Ala was utilized for the regeneration of expensive cofactor NAD+ and removal of by‐product pyruvate. Furthermore, in situ product removal by cation resin adsorption was used to drive the thermodynamic equilibrium of the cascade reaction to the direction of product generation. Finally, optically pure (R)‐phenylglycinol was successfully produced from racemic styrene oxide with high yield (81.9 %) and excellent enantioselectivity (99 % ee). [ABSTRACT FROM AUTHOR]

In this paper, a biocatalytic route is described wherein PPL, lipase from porcine pancreas, in conjunction with water on reaction with different thiophenols and styrene oxides undergo thiolysis with C-S bond formation without the use of any metal catalysts, oxidants, bases, additives or organic solvents towards formation of β-hydroxysulfides in good to excellent yields with high regioselectivity at room temperature. Furthermore, PPL also facilitates thiophenols to undergo hydrothiolation with styrenes or phenylacetylenes in sole water and thus forming linear thioethers or vinylsulfides respectively via C–S bond formation. In addition to the straightforward and atom-efficient protocol, a gram-scale synthesis of β-hydroxysulfide and recyclability for three consecutive cycles without decrease in efficiency of PPL make our biocatalytic protocol for constructing C–S bond highly valuable from both environmental and economic viewpoints than traditional chemical practices. [ABSTRACT FROM AUTHOR]

• Single site aluminosilicate catalysts synthesized and characterized. • Two different aluminum sites targeted – "extraframework" and "framework". • Accessibility of Al sites studied by ligand exchage reactions. • Catalytic activities for aminolysis of styrene oxide by aniline reported. A general synthetic strategy for the preparation of atomically dispersed, well-defined Lewis acidic aluminum sites in silicate matrices is described and illustrated. These amorphous matrices are composed of the spherosilicate cubes (Si 8 O 20) linked together by combinations of aluminum and siloxane groups. The connectivity of the catalytically active aluminum centers to the surrounding silicate matrix can be varied by choice of aluminum precursor. "Extraframework" 3-connected Al⟵Py and Al⟵THF sites are obtained from the corresponding AlCl 3 ·L complexes and 4-connected "framework" sites from Y[AlCl 4 ] (Y = Lutidinium, [Bu 4 N]+). The aluminum sites in these porous silicates are characterized by gravimetry, IR and multinuclear SSNMR spectroscopies as well as ligand exchange reactions. Their catalytic activities as Lewis acids are investigated for the aminolysis of styrene oxide by aniline. These single site aluminosilicate catalysts exhibit activities that are comparable to or better than analogous, well-known zeolite and amorphous aluminosilicate materials. Their activities are dependent on the connectivity of aluminum to the surrounding silicate matrix as well as the length and flexibility of secondary linkers in the matrix. [ABSTRACT FROM AUTHOR]

The CO2 cycloaddition of styrene oxide (SO) catalyzed by different paddlewheel-type di-metal clusters has been investigated by means of density functional calculations. Without a co-catalyst, the reaction proceeds in a single step involving the breaking of a C–O bond of adsorbed epoxide and the simultaneous formation of two new C–O bonds between the adsorbed epoxide and a carbon dioxide. The reaction starts with the adsorption of a styrene oxide molecule on the catalytic site of an M–BTC catalyst via its oxygen atom with adsorption free energies of −12.3, −10.2, −8.0, −3.9, and −13.9 kcal mol−1 for SO adsorption on Fe–, Co–, Ni–, Cu–, and Zn–BTC systems, respectively. From NBO analysis, it was found that the interaction between SO and M–BTC causes a higher polarization of C–O bonds of the epoxide. The more polarized C–O bond of the adsorbed SO allows the nucleophile to attack more easily. The calculated results unambiguously highlight the important role of unsaturated cationic sites in the paddlewheel unit in promoting the catalytic cycloaddition of CO2 with SO. Based on the activation energy, the trend of catalytic activity is in the order Fe–BTC ＞ Zn–BTC ＞ Co–BTC ＞ Ni–BTC ＞ Cu–BTC. From DFT calculations, the Fe–BTC is theoretically proved to have the potential to be a desirable catalyst for the CO2 cycloaddition of styrene oxide in the absence of a co-catalyst. [ABSTRACT FROM AUTHOR]

Epoxidations of indene, styrene, 2‐chlorostyrene, 3‐chlorostyrene, 4‐chlorostyrene, 4‐bromostyrene, and naphthalene using Musa paradisiaca plant juice chloroperoxidase in the presence of H2O2 and t‐butyl peroxide as oxidants have been studied. The steady‐state kinetic parameters, Km and kcat of the enzyme for the above substrates have been determined. The temperature and pH optima of the epoxidation are 25°C and 6.2, respectively. The yield of styrene oxide in the presence of H2O2 was 44%. The results show that M. paradisiaca plant juice chloroperoxidase is a potential biocatalyst for organic epoxidation reactions. [ABSTRACT FROM AUTHOR]

Under conventional conditions of styrene oxide conversion catalyzed by perchloric acid in an alcohol solution (ButOH-chlorobenzene (9 : 1 by vol.), 343 K), an iminium ylide absorption band (λmax ≈ 460–470 nm) was recorded in the presence of pyridine trap, which corresponds to the adduct of pyridine and phenylmethylene. In the presence of oxygen, another intermediate product was detected, the absorption band of which (λmax ≈ 400 nm) coincides with the corresponding carbonyl oxide absorption. A similar observation was made earlier for the acid-catalyzed conversion of styrene oxide in the presence of p-toluenesulfonic acid in alcohol and acetonitrile solutions. Thus, the obtained results confirm formation of active intermediate species of carbene nature in two epoxide-acid systems. [ABSTRACT FROM AUTHOR]

Styrene is an important high production volume chemical used to manufacture polymeric products. In 2018, International Agency for Research on Cancer classified styrene as probably carcinogenic to humans; National Toxicology Program lists styrene as reasonably anticipated to be a human carcinogen. The genotoxicity literature for styrene and its primary metabolite, styrene 7,8‐oxide (SO), begins in the 1970s. Organization of Economic Cooperation and Development (OECD) recently updated most genotoxicity test guidelines, making substantial new recommendations for assay conduct and data evaluation for the standard mutagenicity/clastogenicity assays. Thus, a critical review of the in vitro and in vivo rodent mutagenicity/clastogenicity studies for styrene and SO, based on the latest OECD recommendations, is timely. This critical review considered whether a study was optimally designed, conducted, and interpreted and provides a critical assessment of the evidence for the mutagenicity/clastogenicity of styrene/SO. Information on the ability of styrene/SO to induce other types of genotoxicity endpoints is summarized but not critically reviewed. We conclude that when styrene is metabolized to SO, it can form DNA adducts, and positive in vitro mutagenicity/clastogenicity results can be obtained. SO is mutagenic in bacteria and the in vitro mouse lymphoma gene mutation assay. No rodent in vivo mutation studies were identified. SO is clastogenic in cultured mammalian cells. Although the in vitro assays gave positive responses, styrene/SO is not clastogenic/aneugenic in vivo in rodents. In addition to providing updated information for styrene, this review demonstrates the application of the new OECD guidelines for chemicals with large genetic toxicology databases where published results may or may not be reliable. Environ. Mol. Mutagen. 2019. © 2019 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Morphology control synthesis of zeolitic imidazolate frameworks (ZIFs) is very important to understand its morphology, structure, and catalytic property relationships. Herein, morphology control synthesis of ZIF‐8 was achieved through an efficient and environmentally friendly one‐pot heating strategy. Different sophisticated ZIF‐8, such as solid spheres, hollow spheres, hierarchical particles, and stackable particles, were obtained by using different surfactants as templates. The sophisticated ZIF‐8 can be employed directly as a catalyst for cycloaddition reaction between CO2 and styrene oxide. The high specific surface areas and most abundant acid‐base sites are account for the superior catalytic performance of ZIF‐8 solid spheres, and the rich mesopores provides channels for the mass transfer of large reactants or product molecules, facilitating the accessibility of reactive sites and increasing catalytic activity. ZIF‐8 solid spheres showed enhanced catalytic activity and excellent recyclability and are thus potential heterogeneous catalysts in various catalytic reactions. [ABSTRACT FROM AUTHOR]

A heterogeneous copper Schiff base complex intercalated in layered double hydroxide, abbreviated as LDH-[SALABACu(II)] has been synthesized and characterized by various analytical techniques like XRD, EDX, FTIR, SEM, ICP-AES, TGA, BET surface area, XPS etc. Its catalytic activity has been examined for oxidation of styrene using 70% tert-butyl hydroperoxide as an oxidant in acetonitrile solvent. The oxidation products have been styrene oxide, benzaldehyde and benzoic acid have been obtained in which styrene oxide is obtained as major oxidation product under optimized conditions. A maximum 81.27% conversion of styrene has been obtained after 5 h of reaction. The catalyst, LDH-[SALABA-Cu(II)] has been recycled ten times in consecutive runs without much loss of catalytic activity. Quenching study has also been performed using p-benzoquinone in order to find out the mode of mechanism. [ABSTRACT FROM AUTHOR]

Graphical abstract Synthesis of cyclic carbonates from CO 2 and epoxides. Highlights • Mn-based MOF including imidazole linker was observed with the highest catalytic activity. • Carbon dioxide can be inserted into various epoxides in the presence of Im-MnF sample. • 94.99% yield of allyl-glycidyl carbonate was obtained under the optimal conditions. • A proposed mechanism was in line with the DFT calculation. Abstract The present work is aimed to investigate the catalytic activities of various Mn-based MOFs for carbon dioxide coupling with epoxides. The metal organic frameworks, [(CH 3 NH 3 ][Mn(COOH) 3 ] (MA-MnF), [(CH 3 CH 2 NH 3 ][Mn(COOH) 3 ] (EA-MnF), and [C 3 H 5 N 2 ][Mn(COOH) 3 ] (Im-MnF) were studied via several characterizations such as XRD, FT-IR, XPS, N 2 -adsorption, TG-DSC, CO 2 -adsorption and NH 3 -TPD. Interestingly, Im-MnF compound was observed to possess the highest catalytic activity among the studied compounds, which is associated not only with the amounts of basic sites, but also related to the nitrogen-containing species. 97.27% conversion of allyl-glycidyl ether (AGE, TOF: 36.78 h−1) and 97.66% selectivity to allyl-glycidyl carbonate (AGC) were obtained under the explored optimized conditions (100 °C, 15 bar, 6 h, 1.0 wt% of AGE). In addition, only a slight downward in catalytic activity was found when the sample was reused twice. Furthermore, coupling reactions of CO 2 with various epoxides were also performed, of which, the yield of the cyclic carbonates followed the order: Epichlorohydrin > Allyl glycidyl ether > Styrene oxide > Cyclohexene oxide > Propylene oxide. Finally, a mechanism was proposed, which is in good agreement with the DFT calculation. [ABSTRACT FROM AUTHOR]

Vinyl epoxides and styrene oxide can react with diborylmethide lithium salts through an exclusive SN2 borylmethylation/ring opening in a regio‐ and diastereoselective way, depending on the nature of the substrate. The ring‐opening protocol provides homoallylboronates that can be transformed into challenging diastereomeric bishomoallylic alicyclic 1,3‐diols. Unprecedented 3‐borylated 1,2‐oxaborolan‐2‐ol products were prepared by borylmethylation/ring opening of 2‐methyl‐2‐vinyloxirane followed by intramolecular cyclization. [ABSTRACT FROM AUTHOR]

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/RGO 5 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/RGO 5 has much better catalytic activity in comparison with other composite catalysts previously reported. Moreover, cycling test shows that the nanocomposite has good catalytic stability. Schematic diagram illustrating the mechanism of epoxidation of styrene over NiCo LDH/RGO. Unlabelled Image • Preparation of flower-like NiCo LDH/RGO composite by one-step solvothermal method • NiCo LDH/RGO composites has excellent catalytic effect on styrene epoxidation. • NiCO LDH/RGO composites are recyclable and have excellent cycle performance. • Synergistic effect of NiCo LDH and graphene enhances the catalytic activity. [ABSTRACT FROM AUTHOR]

A new organic–inorganic hybrid compound contained bi-capped Bi Keggin anion, [biim][PMo1VMo11VIBi1.24O40]·3H2O (1) (biim = biimidazole) has been firstly synthesized and characterized by IR, UV–Vis, XRD, XPS, elemental analyses, fluorescent spectrum and TG analysis. Compound 1 exhibits a novel 2-D supramolecular network structure constructed from {PMo1VMo11VIBi1.24O40} anions by O···O interactions, and further extends a 3-D supramolecular framework by bridges of biimidazole with N–H···O hydrogen bonding interactions. The compound 1 performs well catalytic property for epoxidation of styrene to styrene oxide. Moreover, compound 1 displays excellent photodegradation activity for methyl orange dye. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Numerous stress responses are induced by chloroacetaldehyde and styrene oxide. • DNA damage is most prominent category of stress responses. • Strains lacking recA, ruvA , and ybfE are sensitive to chloroacetaldehyde. • Strains lacking recA , mutM , nfo , uvrA , uvrD , ybfE are sensitive to styrene oxide. Abstract DNA damage is ubiquitous and can arise from endogenous or exogenous sources. DNA-damaging alkylating agents are present in environmental toxicants as well as in cancer chemotherapy drugs and are a constant threat, which can lead to mutations or cell death. All organisms have multiple DNA repair and DNA damage tolerance pathways to resist the potentially negative effects of exposure to alkylating agents. In bacteria, many of the genes in these pathways are regulated as part of the SOS reponse or the adaptive response. In this work, we probed the cellular responses to the alkylating agents chloroacetaldehyde (CAA), which is a metabolite of 1,2-dichloroethane used to produce polyvinyl chloride, and styrene oxide (SO), a major metabolite of styrene used in the production of polystyrene and other polymers. Vinyl chloride and styrene are produced on an industrial scale of billions of kilograms annually and thus have a high potential for environmental exposure. To identify stress response genes in E. coli that are responsible for tolerance to the reactive metabolites CAA and SO, we used libraries of transcriptional reporters and gene deletion strains. In response to both alkylating agents, genes associated with several different stress pathways were upregulated, including protein, membrane, and oxidative stress, as well as DNA damage. E. coli strains lacking genes involved in base excision repair and nucleotide excision repair were sensitive to SO, whereas strains lacking recA and the SOS gene ybfE were sensitive to both alkylating agents tested. This work indicates the varied systems involved in cellular responses to alkylating agents, and highlights the specific DNA repair genes involved in the responses. [ABSTRACT FROM AUTHOR]

Abstract To elevate the concentration of racemic styrene oxide (rac -SO), its asymmetric hydrolysis in organic/aqueous biphasic system was researched. Firstly, n -octane/phosphate buffer reaction system was constructed, where Pv EH2 retained 75.9% activity at 25 °C for 8 h. Secondly, the optimal volume ratio of two phases and weight ratio of rac -SO to E. coli / pveh2 were 4:6 and 0.8. Then, the maximum allowable rac -SO concentration was assayed as 200 mM, 10-fold that in aqueous phase. Finally, the hydrolysis of rac -SO was performed, affording (R)-SO with over 99.5% ee s and 47.8% yield, and (R)-phenyl-1,2-ethanediol with 93.6% ee p and 50.4% yield in 12 h. Graphical abstract Unlabelled Image Highlights • Pv EH2 was more stable in long-chain alkanes than in alcohols. • Racemic styrene oxide (rac -SO) was hydrolyzed in n -octane/aqueous system by Pv EH2. • The rac -SO concentration in biphasic system was 10-fold that in single aqueous phase. • (R)-SO with >99.5% ee s and (R)-phenyl-1,2-ethanediol with 93.6% ee p were coproduced. • The volumetric productivity of (R)-SO (0.96 g/L/h) was the highest ever reported. [ABSTRACT FROM AUTHOR]

[Display omitted] • Alcoholysis mechanisms of styrene oxide (StyOx) are discussed. • Hydronium ion via homogenous catalysis can catalyze StyOx alcoholysis. • The product of StyOx alcoholysis catalyzed by CB7 solid has a good selectivity to produce pure β -alkoxy alcohol. Heterogeneous and supramolecular catalysis are fundamental processes in chemistry. To understand the synergistic role between heterogeneous and supramolecular catalysis, the catalytic mechanism of cucurbituril solid for epoxide alcoholysis was investigated by performing density functional theory (DFT) calculations. The results reveal that styrene oxide (StyOx) ethanolysis has an inherent regioselectivity, which results from different groups linked to the epoxy group. The hydronium ion can catalyze the ring-opening of StyOx ethanolysis and lead to the formation of a planar carbenium ion. StyOx can also be hydrolyzed via the homogenous catalysis of acid to produce 1, 2-diol. Cucurbituril solid can catalyze epoxide alcoholysis because of its acidic property. Its unique cavity can lead to a favorable frontside-attack of the alcohol on the carbenium ion. The product from the heterogeneous catalysis of cucurbituril solid is pure β -alkoxy alcohol. The results are important to understand heterogeneous and supramolecular catalysis and the design of new and effective supramolecular catalysts. [ABSTRACT FROM AUTHOR]

In this study we have combined the bioreduction of α-bromoketones using carrot root as biocatalyst and click chemistry for the preparation of enantiopure β-hydroxytriazoles in excellent enantiomeric excesses and yields. Moreover, we have utilized chiral α-halohydrins for the synthesis of enantiopure styrene oxides in very good yields and enantiomeric excesses. Structural assignments of the products were based on their 1H and 13C NMR data and their optical rotations. The enantiomeric excess of the chiral products was obtained by HPLC analysis. [ABSTRACT FROM AUTHOR]

Abstract The structure and spectroscopic properties of nickel methylxanthate, Ni(S 2 COCH 3) 2 , as isolated molecule and in crystalline phase, were investigated both experimentally and theoretically. Experimentally, single crystal X-ray diffraction, infrared and ultraviolet–visible spectroscopies have been used, while the applied theoretical approaches include density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations. The isolated molecule of the complex under study was found to exist in two nearly degenerated conformers (cis and trans , with the methyl groups of the ligand molecules positioned the same side or in opposite sides of the molecule, respectively). The trans conformer is selected upon crystallization. The crystal structure (at 100 K) was solved and discussed, with emphasis given to the characterization of the main intermolecular interactions. The infrared spectrum (in the 3500-300 cm−1 range) of the crystalline material was assigned in details, also taking into account the results of the normal coordinate analysis performed for the isolated molecule, which in turn was made using the data resulting from the DFT calculations. The UV–visible spectrum of the compound in CHCl 3 solution was also obtained and interpreted based on results of TD-DFT calculations, demonstrating the importance of the metal to ligand charge transfer in the studied complex. Finally, the catalytic activity of the complex for ring-opening reaction of styrene oxide resulting from nucleophilic attack of anilines was also evaluated, showing that the compound presents potential as catalyzer of this type of reactions. Graphical abstract Image Highlights • The isolated molecule of Ni(S 2 COCH 3) 2 exists in two nearly degenerated conformers, cis and trans. • The trans conformer is selected upon crystallization. • TD-DFT calculations, demonstrated the importance of the metal to ligand charge transfer in the complex. • The catalytic activity of the complex for ring-opening reaction of styrene oxide with anilines was evaluated. [ABSTRACT FROM AUTHOR]

[Display omitted] • Calcined Ge-UTL encountered structural degradation under pure water solution at RT. • A simply ultrasonic treatment caused random arrangement of the formed cfi layers. • The stacking faults of cfi layers generated abundant intracrystal mesopores. • An excellent styrene epoxidation activity (TOF = 403 h−1) is achieved on Co-Meso-UTL. Co-zeolites with hierarchical porous are significantly desirable for the liquid-phase selective epoxidation of styrene that required relatively open reaction spaces. A typical UTL germanosilicate with the absence of organic structure-directing agent molecules inside pore channels suffered from severe structural collapse after ultrasonic treatment under pure water medium, originating from the unstable germanium-rich double four ring subunits. The simple strategy cleaved the weak linkage Ge-O bands and caused the irregular location of silicon-rich cfi layers. Subsequently, Co activity centers was incorporated into the framework through reacting with the abundant silanol groups located in the hydroxyl nests at room temperature. The random arrangement of mono- or multi- cfi layers induced the stacking faults and generated a large amount of intracrystal mesopores after calcination. The resultant Co-Meso-UTL catalysts favored the molecules diffusion of large-sized styrene and target products, improving the accessibility of Co active sites and exhibiting excellent catalytic performance in the styrene epoxidation reaction with single hydrogen peroxide (H 2 O 2) oxidant. Especially, high styrene oxide product selectivity was also obtained through controlling appropriate H 2 O 2 -added content as well as reaction time, which possessed a highest turnover frequency value of 403 h−1 among the reported catalysts. [ABSTRACT FROM AUTHOR]

Cellulose graft copolymers having well-defined structures could incorporate the characteristics of both the cellulose skeleton and side chains, providing a new method for the preparation functionalised cellulose derivatives. Herein, a series of multifunctional cellulose grafted, alternating 3,4-dihydrocoumarin (DHC) and epoxide (EPO) copolymers (cell- g -P(DHC- alt -EPO)) were prepared in a metal-free DBU/DMSO/CO 2 solvent system without adding additional catalyst. Four examples of cell- g -P(DHC- alt -EPO) with tunable thermal and optical properties were synthesized by copolymerization of DHC with styrene oxide (SO), propylene oxide (PO), cyclohexene oxide (CHO) or furfuryl glycidyl ether (FGE) onto cellulose. The nonconjugated cell- g -P(DHC- alt -EPO) showed UV absorption properties with the maximum absorption peak at 282 nm and 295 nm and photoluminescence performance. A clustering-triggered emission mechanism was confirmed and consistent with DFT theoretical calculations. In DMSO solution, the copolymer (DHCSO5) with DP of 11.64 showed ACQ behaviour as the concentration increased. In addition, DHCSO5 had good antioxidant capacity with an instantaneous radical scavenging activity of 2,2-diphenyl-1-picrylhydrazine (DPPH) up to 65 % at a concentration of 40 mg/ ml and increased to 100 % after 30 min. Thus, the multifunctional cell- g -P(DHC- alt -EPO) materials had a variety of potential applications in the fields of fluorescent printing, bio-imaging, UV- shielding and antioxidants. [ABSTRACT FROM AUTHOR]

Olefin epoxidation has been studied over a series of mesoporous manganese silicate nanoparticles and tBuOOH. Partial substitution of Si by Mn in silica framework leads to highly dispersed, distorted Mn(III) sites, confirmed by various physicochemical analyses. High conversion and stable styrene oxide, stilbene oxide and epoxy cyclohexane yield have been achieved with MS75 with 1:1.5 ratio of olefin: oxidant. However, at faster reaction rates lower styrene oxide yield is observed at lower Mn-containing catalyst (MS100). High TON, TOF over manganese sites shows accessible monomeric Mn sites. Attributed to high reactant density at redox-active Mn silicate sites due to facile diffusion across shallow pore depth channels of nanoparticulate om- MS x and surface hydrophobic characteristics. The catalysts were found to be stable under recycling and filtration experiments. The excellent stability against leaching of active manganese species indicates stable sites and good textural properties in om- MS x, essential for extended activity. [Display omitted] • Highly dispersed Mn doped ordered mesoporous silica nanoparticles are prepared. • High activity and epoxide selectivity with higher TON, TOF were achieved. • Facile diffusion of molecules is achieved across the shallow channel depths. • At a 1:1.5 stoichiometry of reactant:oxidant, efficient epoxidation is realized. • Hydrophobic surface nature assists in high reactant density across active sites. [ABSTRACT FROM AUTHOR]