Catalytic Epoxidation Research Articles

Catalytic Epoxidation of Carbonyl Compounds via Carbonyl Ylides: from Racemic to Enantioselective.

Transition metal-catalyzed epoxidation of carbonyl compounds through carbonyl ylides represents a highly effective method for synthesizing a diverse range of valuable epoxides. This review offers an in-depth overview of the latest developments in inter- and intramolecular epoxidation reactions involving metal carbenes and carbonyl compounds, encompassing both racemic to enantioselective transformations. These catalytic epoxidations are reviewed by highlighting their product selectivity, diversity and applicability, and the related mechanistic rationale is showcased where possible.

Synthesis of titanium silicalite-1 supported zinc catalysts for efficient and clean epoxidation of 1-hexene and methyl oleate

To improve the catalytic epoxidation activity of conventional TS-1 zeolite under acid-free conditions, a series of TS-1-supported zinc (xZn/TS-1) catalysts were prepared and evaluated in the epoxidation of 1-hexene and methyl oleate (MO) with H2O2 oxidant. The microstructure of xZn/TS-1 was investigated using various characterization techniques, and the results showed that the introduction of Zn species was not only well dispersed on the surface of TS-1 but also did not disrupt the crystal structure of TS-1 and tetrahedral framework titanium. Furthermore, the Ti-O-Zn structure can be formed between Zn and Ti species through O-atomic coordination, which improves the vulnerability of the Ti-O bond to attack the H2O2 molecule, and ultimately facilitates the epoxidation reaction between 1-hexene and MO. In addition, the 2% Zn/TS-1 catalysts showed optimal conversions of 45.7 % and 75.41 % for 1-hexene and MO, respectively, and exhibited good catalytic stability and regeneration during the epoxidation process.

Aliphatic Olefin Epoxidation with Hydrogen Peroxide Catalyzed by an Integrated Mn/TS-1/N System

AbstractPropylene liquid-phase epoxidation with 50–75% H2O2 is an important process for the industrial production of propylene oxide (PO). To realize a propylene epoxidation process that proceeds with low hydrogen peroxide concentration, we developed an integrated Mn/TS-1/N catalytic system via in-situ reaction of Mn/TS-1 with an N-donor ligand, affording the PO product in excellent yield with only 30 wt% H2O2. Other long-chain aliphatic epoxides were also readily synthesized by this catalytic epoxidation system. Moreover, in addition to the standard micro-pressure reactor, a continuous-flow microreactor was developed that executed the hydrogen peroxide propylene oxide (HPPO) process with excellent efficiency for 1300 hours. This innovative Mn/TS-1/N catalyzed epoxidation represents a promising direction for advancing HPPO industrial processes, offering improved efficiency while minimizing the reliance on high concentrations of H2O2.

Facile synthesis of nanoscale CuO and NiO via the PVA-assisted sol-gel method and their exploration in the catalytic epoxidation of styrene

The full-text of the article will be published in the English version of the journal "Catalysis in Industry" No. 4, 2024.Both nanoscale copper oxide and nickel oxides, with diameter 17 and 25 nm respectively, have been synthesized via an easy sol-gel method using polyvinyl alcohol. The method involves the simple dispersion of metal ions (M2+ = Cu or Ni) into the PVA gel and subsequent calcination of the dried gel at 400 °C for 3 h. The synthesized oxide materials are characterized by different physical tools like TGA, powder XRD, SEM, TEM and DRS UV-visible spectroscopic technique. The oxides are found to be very efficient catalysts in the epoxidation of styrene. CuO gives 87 % styrene conversion and 88 % SO selectivity while, NiO gives 69 % styrene conversion and 80 % with TBHP as an oxidant at the end of 6 h. Both the catalysts can suitably be reused for several successive runs without appreciable loss in activity and selectivity. The cost-effective synthesis, excellent catalytic performance and reusability make these oxides promising catalysts for the industrial use.

Catalytic epoxidation of sunflower oil derived by linoleic acid via in situ peracid mechanism

Catalytic epoxidation of sunflower oil derived by linoleic acid via in situ peracid mechanism

Sustainable approach for catalytic epoxidation of oleic acid followed by in situ ring-opening hydrolysis with applied ion exchange resin

Abstract Vegetable oils are rich in unsaturated bonds that can be converted to epoxidized oleic acid. They are considered sustainable, renewable, and also environmentally friendly. To date, there is a paucity of studies on production of dihydroxystearic acid (DHSA) using an eco-friendly ion exchange resin as it is not fully utilised. As a result, the aim of this study is to elucidate the mechanism of ring-opening by hydrolysis for the production of DHSA using amberlite IR-120H as a catalyst. The process of epoxidizing oleic acid involved the in situ generation of performic acid, which was then used to convert oleic acid into epoxidized oleic acid. This performic acid was created by combining formic acid, serving as the oxygen carrier, with hydrogen peroxide, acting as the oxygen donor. Under optimal conditions, the maximum relative conversion of oleic acid to oxirane was attained, with up to 85 %. Overall, DHSA with a high hydroxyl value (182 mg KOH/g), was successfully produced from oleic acid using in situ hydrolysis of epoxidized oleic acid.

Chemical modification of linoleic acid via catalytic epoxidation of corn oil: A sustainable approach

AbstractEpoxidized corn oil is of great interest because they are derived from sustainable, renewable natural resources and are environmentally friendly. There is a lack of extensive research on optimizing process parameters for the epoxidation of corn oil, which serves as the raw material. In this study, the epoxidation of corn oil was carried out by reacting formic acid and hydrogen peroxide, employing an in situ peracids mechanism. The findings revealed that the optimal reaction conditions for producing epoxidized corn oil with the highest oxirane content were a catalyst type of sulfuric acid, reaction temperature of 35°C, a molar ratio of formic acid to linoleic acid of 1:1, and a molar ratio of hydrogen peroxide to linoleic acid of 1.75:1. By employing these optimal conditions, the maximum relative conversion of palm oleic acid to oxirane was achieved at 82%. After 100 iterations, the reaction rate constant based on optimized epoxidized corn oil production was obtained as follows: = 0.13 mol L−1 min−1, = 37.07 mol L−1 min−1, and = 10.00 mol L−1 min−1. The findings validated the kinetic model by showing good agreement between the simulation and experimental data.

Trimetallic MOF1@MOF2 heterostructure derived Co–NC@CuM–C for enhanced photothermal catalysis in styrene epoxidation

A trimetallic BMZIF@HKUST-1 heterostructure was successfully synthesized by directed epitaxial growth. Co–NC@CuOPd–C exhibited high SO yield (92.9%) for styrene epoxidation.

Visible-light-promoted catalytic epoxidation of alkenes under metal-free conditions

In this work, we report a method for the synthesis of functionalized epoxy analogues using the synergistic interaction of 4CzIPN and oxygen under visible light stimulation.

Exploring the impact of abnormal coordination in macrocyclic N-heterocyclic carbene ligands on bio-inspired iron epoxidation catalysis

Macrocyclic and abnormal NHC iron complexes are characterised, showing high catalytic activity in epoxidation reaction and potential for ligand design.

Chiral imidazolium and triazolium salts as NHC and aNHC ligand precursors: A promising framework for asymmetric epoxidation catalysis

Two chiral imidazolium salts and one chiral triazolium salt were synthesized containing a chiral cyclohexane bridge based on the salen ligand framework of the Jacobsen-Katsuki epoxidation catalysts. They are promising NHC and aNHC ligand precursors for asymmetric epoxidation or C–H oxidation catalyzed by organometallic compounds. The ligand framework offers plenty of opportunities for modification.

Thermocatalytic epoxidation by cobalt sulfide inspired by the material's electrocatalytic activity for oxygen evolution reaction.

New discoveries in catalysis by earth-abundant materials can be guided by leveraging knowledge across two sub-disciplines of heterogeneous catalysis: electrocatalysis and thermocatalysis. Cobalt sulfide has been reported to be a highly active electrocatalyst for the oxygen evolution reaction (OER). Under these oxidative conditions, cobalt sulfide forms oxidized surfaces that outperform directly prepared cobalt oxide in OER catalysis. We postulated that the catalytic activity of oxidized cobalt sulfide for OER could reflect a more general ability to catalyze O-transfer reactions. Herein, we show that cobalt sulfide (CoS x ) indeed catalyzes the epoxidation of cyclooctene, a thermal O-transfer reaction. Similarly to OER, the surface-oxidized CoS x formed under reaction conditions outperformed the directly prepared cobalt oxide, hydroxide, and oxyhydroxide for epoxidation catalysis. Another notable phenomenological parallel to OER was revealed by the electron paramagnetic resonance (EPR) analysis of all spent Co-based catalysts that showed significant structural changes and the formation of paramagnetic Co(ii) and Co(iv) species. Mechanistic investigations suggest that a higher density of Co(ii) and/or an easier formation of high-valent Co species in the case of surface-oxidized cobalt sulfide is responsible for its high activity as an epoxidation catalyst. Our results provide important insight into the surface chemistry of Co-based catalysts and show the potential of oxidized CoS x as an earth-abundant catalyst for O-transfer reactivity beyond OER. This work highlights the utility of bridging electrocatalysis and thermocatalysis for the development of more sustainable chemical processes.

Vacancy-Rich Carbon-Coated Niobium Carbide Prepared via Carbothermal Reduction of Biomass-Based Carbon Precursors for Efficient Catalytic Epoxidation

Vacancy-Rich Carbon-Coated Niobium Carbide Prepared via Carbothermal Reduction of Biomass-Based Carbon Precursors for Efficient Catalytic Epoxidation

Chemical Fixation of CO2 with Epoxides Catalyzed by Zinc Metalated Schiff Base Organic Polymer

Chemical Fixation of CO2 with Epoxides Catalyzed by Zinc Metalated Schiff Base Organic Polymer

Green catalytic epoxidation of hybrid oleic acid derived from waste palm cooking oil + palm oil

Green catalytic epoxidation of hybrid oleic acid derived from waste palm cooking oil + palm oil

Decomposition of hydrogen peroxide during catalytic epoxidation of propylene

Decomposition of hydrogen peroxide during catalytic epoxidation of propylene

A Lewis Acid-Controlled Enantiodivergent Epoxidation of Aldehydes.

Two epoxidation catalysts, one of which consists of two VANOL ligands and an aluminum and the other that consists of two VANOL ligands and a boron, were compared. Both catalysts are highly effective in the catalytic asymmetric epoxidation of a variety of aromatic and aliphatic aldehydes with diazoacetamides, giving high yields and excellent asymmetric inductions. The aluminum catalyst is effective at 0 °C and the boron catalyst at -40 °C. Although both the aluminum and boron catalysts of (R)-VANOL give very high asymmetric inductions (up to 99% ee), they give opposite enantiomers of the epoxide. The mechanism, rate- and enantioselectivity-determining step, and origin of enantiodivergence are evaluated using density functional theory calculations.

Sustainable approach for catalytic green epoxidation of oleic acid with applied ion exchange resin

Epoxides were primarily derived from petroleum-based sources. However, there has been limited research on optimizing the process parameters for epoxidized palm oil-derived oleic acid, resulting in its underutilization. Therefore, this study aimed to optimize the catalytic epoxidation of palm oleic acid concerning the oxirane content by applying ion exchange resin as a catalyst. Epoxidized oleic acid was produced using in-situ-formed performic acid by combining formic acid as the oxygen carrier with hydrogen peroxide as the oxygen donor. The findings revealed that the optimal reaction conditions for producing epoxidized oleic acid with the highest oxirane content were an Amberlite IR-120 catalyst loading of 0.9 g, a molar ratio of formic acid to oleic acid of 1:1., and a molar ratio of hydrogen peroxide to oleic acid of 1:1.1. By employing these optimal conditions, the maximum relative conversion of palm oleic acid to oxirane was achieved at 85%. The reaction rate constants (k) based on the optimized epoxidized oleic acid are determined as follows: k11 = 20 mol L−1 min−1, k12 = 2 mol L−1 min−1, and k2 = 20 mol L−1 min−1. The findings validated the kinetic model by showing good agreement between the simulation and experimental data.

Catalytic Epoxidation of Oleic Acid Derived from Waste Cooking Oil by In Situ Peracids

Catalytic Epoxidation of Oleic Acid Derived from Waste Cooking Oil by In Situ Peracids

Production of limonene epoxides from tire pyrolysis oil by polyoxometalate immobilized on SBA-15

The goal of producing limonene epoxide and separating p-cymene from tire pyrolysis oil (TPO) could be achieved after epoxidation. However, the existing catalytic epoxidation process has the problem of cumbersome catalyst separation process, which is not conducive to industrial applications. In this work, the heterogeneous catalysts polyoxometalate-SBA-15 were prepared with the point of simplifying separation process. Heteropoly acid anions (phosphotungstic acid or peroxophosphotungstic acid) with catalytic active successfully enter the mesoporous pores of SBA-15, exhibiting high limonene conversion in the TPO system. The PW4 species produced by phosphotungstic acid after oxidation of H2O2 was favorable for improving the selectivity of epoxidation. The catalyst S-D-PW4 prepared showed high catalytic activity and epoxidation selectivity with the condition of H2O2 as an oxidant and free of solvent. Furthermore, A statistical experimental approach was used to comprehensively evaluate the reaction conditions. The conversion of limonene in TPO could reach 99.78%, and the yield of 1,2-limonene epoxide and diepoxide were 67.96% and 20.16%, respectively. A variety of characterization techniques such as 31P NMR, XPS, and ICP were employed to analyze the difference in catalyst before and after epoxidation. S-D-PW4 could be easily separated and the catalytic activity and epoxidation selectivity remained high after 5 cycles.