Selective Oxidation Of 2-methylnaphthalene Research Articles

Influence of support properties on selective oxidation of 2-methylnaphthalene on vanadia-molybdena based catalyst

In this work, the catalytic performance of vanadia-molybdena loaded on TiO2, MgO, ZSM-5, NaY and Mordenite was investigated in the selective oxidation of 2-methylnaphthalene (2-MN) to 2-naphthaldehyde (2-NA). Results show that strong interactions between supports (TiO2, ZSM-5) and active components can promote the dispersion of active component. Monolayer VOx and MoOx are the main form on the catalyst surface, which is beneficial to the 2-NA selectivity. However, the corresponding weak interactions between Mordenite and active components may lead to the production of oxide crystals and the separation of active components, thus reducing the 2-NA selectivity. Due to the high Na content, new crystal NaVMoO6 forms on the NaY surface, which is inactive in the reaction. For V-Mo/TiO2, V and Mo can be inserted into the TiO2 lattice, changing the electronic structures of active components and support and improving the activity of surface oxygen species. This investigation highlights an important consideration on supports properties when designing supported catalysts.

Synthesis and Catalytic Activities of Copper(I) Complexes of Bis(diphenylphosphinomethyl)amino Ligand and its Silica-supported Form

Cu(I) complexes of free ditertiary aminomethylphosphine ligand, N,N-bis(diphenylphosphinomethyl)aminopropyltriethox- ysilane (DIPAPTES) and its silica supported form (SiO2-DIPAPES), have been synthesized under nitrogen atmosphere using Schlenk method and characterized by atomic absorption, FT-IR, NMR (1H and 31P), and elemental analysis. Acetylacetonate (acac)− complexes of Cr(III) and Mn(III) complexes were prepared according to the literature. All the complexes were used as catalysts for the oxidation of 2-methyl naphthalene (2MN) to 2-methyl-1,4-naphthoquinone (Vitamin K3, menadione, 2MNQ) using hydrogen peroxide as a clean and cheap oxidant. All the complexes did not show good catalytic activity for the selective oxidation of 2-methyl naphthalene to 2-methyl-1,4-naphthoquinone.

Catalytic Synthesis of 2-Methyl-1,4-Naphthoquinone (Vitamin K3) Over Silica-Supported Aminomethyl Phosphine-Ru(II), Pd(II), and Co(II) Complexes

Ru(II), Pd(II), and Co(II) complexes of the free ditertiary aminomethylphosphine ligand, N,N-bis(diphenylphosphinomethyl)aminopropyltriethoxysilane [(EtO)3Si(CH2)3 N(CH2PPh2)2] (DIPAPTES), and its SiO2-DIPAPES have been synthesized under a nitrogen atmosphere using Schlenk techniques. All the complexes were used as catalysts for the oxidation of 2-methyl naphthalene (2MN) to give 2-methyl-1,4-naphthoquinone (vitamin K3, menadione, 2MNQ) in the presence of hydrogen peroxide as a clean and cheap oxidant. The catalytic synthesis of vitamin K3 was investigated using both homogeneous catalysis with free complexes and heterogeneous catalysis with silica-supported complexes. [(DIPAPTES)PdCl2] and its silica-supported form showed the best catalytic activity for the selective oxidation of 2-methyl naphthalene to 2-methyl-1,4-naphtoquinone compared to the other metal complexes. 2MNQ yield reached 52.26% with the 2MN conversion of 90.52% using complex [(DIPAPTES)PdCl2] and 58.59% with the 2MN conversion of 99.56% using the silica supported [SiO2(DIPAPES)PdCl2] complex for 1 h. Recycling was investigated for the silica-supported Pd(II) complex and compared with the classical production of vitamin K3. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.

Synthesis of Silica-Supported Platinum(II) and Nickel(II) Complexes of Bis(Diphenylphosphinomethyl)Amino Ligand: Applications as Catalysts for the Synthesis of 2-Methyl-1,4-Naphthoquinone (Vitamin K3)

Pt(II) and Ni(II) complexes of N,N-bis(diphenylphosphinomethyl)aminopropyltriethoxysilane [(CH3CH2O)3Si(CH2)3N(CH2PPh2)2] (DIPAPTES) and silica supported [SiO2–(DIPAPES)] ligands have been synthesized under nitrogen atmosphere using Schlenk method and characterized by using atomic absorption, FT-IR, NMR (1H and 31P) and elemental analysis techniques. All the complexes were used as catalysts for the oxidation of 2-methyl naphthalene (2MN) to 2-methyl-1,4-naphthoquinone (vitamin K3, menadione, 2MNQ) using hydrogen peroxide as a clean and cheap oxidant. [Pt–(DIPAPTES)Cl2] and supported complex [SiO2–(DIPAPES)–PtCl2] showed medium catalytic activity whereas Ni(II) complexes did not show any catalytic activity for the selective oxidation of 2-methyl naphthalene to 2-methyl-1,4-naphthoquinone.

Studies of Vitamin K3 synthesis over Ti-containing mesoporous material

In this paper we report the synthesis of Vitamin K3 or Menadione by selective oxidation of 2-methyl naphthalene with H2O2 using Ti-MCM-41 synthesized by different methods. We studied the relationship between the catalytic activity and the structural characteristics and the coordination number of Ti of the catalyst. Different parameters affecting the oxidation of 2-methyl naphthalene like amount of the catalyst, hydrogen peroxide/substrate ratio, reaction temperature and the nature of the solvent are described. The experiment design—response surface methodology is used in this work to optimize the selective oxidation of 2-methyl naphthalene to vitamin K3. The application of this methodology lead us to a better understanding of the influence of the different factors (amount of catalyst, reaction temperature, H2O2 and reaction time); and their interactions, reducing the operation costs, achieving efficiency and effectiveness in this process.

Synthesis of menadione over selective oxidation zeolites

We report on the synthesis of Menadione (vitamin K 3) by selective oxidation of 2-methylnaphthalene (2MN) with hydrogen peroxide over Ti- and Fe-containing catalysts. Different parameters affecting the oxidation of 2-methylnaphthalene with hydrogen peroxide on zeolite Fe-Beta are described. The influence of the amount of catalyst as well as the concentration of hydrogen peroxide and the influence of the reaction temperature on the reaction rate were studied. The effect of the nature of the solvent was also investigated. All tests were performed over several selective oxidation zeolitic catalysts, synthesized and characterized in our laboratory.