Oxidation Of 2-methylnaphthalene Research Articles

Polymerized methyl imidazole silver bromide (CH3C6H5AgBr)6: Synthesis, crystal structures, and catalytic activity

Abstract One-pot synthesis of polymerized methyl imidazole silver bromide (CH3C6H5AgBr)6 Compound 1 was carried out by the reaction of methylimidazole, 1,2-dibromoethane, and Ag2O in tetrahydrofuran at 60°C for 2 h. Compound 1 was characterized by elemental analysis, 1 H nuclear magnetic resonance, and single crystal X-ray diffraction. The crystal cell parameters of Compound 1 are as follows: a = 8.916(4) Å, b = 17.655(9) Å, c = 9.024(4) Å, α = 90°, β = 103.621(7)°, γ = 90°, V = 1380.6(12) Å3, and Z = 4. The silver atoms in Compound 1 are pentacoordinated with three bromine atoms, one silver atom, and one nitrogen atom of methyl imidazole, and polymeric methyl imidazole silver bromide was formed based on this structure. The catalytic effects under optimized conditions were investigated in this study, and the results showed that Compound 1 possesses a strong catalytic effect on the oxidation of 2-methylnaphthalene with a conversion rate of 77.15% by using hydrogen peroxide as the oxidant at 80°C for 3 h. The catalytic mechanism was explored simultaneously.

Synthesis of Novel Azo-Azomethine-Based Pd(II) Complexes and Catalytic Activities in the Synthesis of Vitamin K3 (2-Methyl-1,4-Naphthoquinone)

Five types of azo-azomethine ligands (6–10) have been synthesized from the reaction of azo aldehyde derivatives with aniline. Structures of the synthesized ligand were characterized with 13C-NMR, 1H-NMR, UV–Visible spectroscopy, elemental analysis, and FT-IR. The Pd(II) complexes were synthesized from the reaction of free ligands with Na2PdCl4. From FTIR, UV–visible, 13C-NMR, 1H-NMR, elemental analysis, and HRMS analysis results, it was understood that palladium metal is bound by N and O atoms in the ligands. The catalytic activities of complexes were investigated in the synthesis of 2-methyl-1,4-naphthoquinone (vitamin K3, 2MNQ, and menadione) with the oxidation of 2-methyl naphthalene (2MN) substrate. Acidic media (sulfuric acid, acetic acid, and hydrogen peroxide) was used as a strongly oxidizing agent in the reaction. Selectivities were reached over 75% with conversions over 89% using the Pd(II) complexes as catalysts.

Synthesis and Characterization of Graphene Based Hybrid Ligands and Their Metal Complexes: Investigation of Chemosensor and Catalytic Properties

It has been synthesized the graphene oxide-based hybrid ligands and their Cu(II), Co(II) and Ni(II) complexes. Firstly, GO was reacted with 3-(trimethoxysilyl)propylamine in ethanol and the obtained structure was treated with 2,6-diformyl-4-bromophenol and 2,6-diformyl-4-tert-butylphenol in order to obtain the hybrid ligands HL1 and HL2. The synthesized hybrid ligands and their metal complexes have been and characterized by using FTIR, UV–vis., XRD, EDX, SEM, TEM, cyclic voltammetry, TG/DTA and ICP-OES techniques. Catalytic activities of Cu(II), Co(II) and Ni(II) complexes of the synthesized ligands have been investigated in the oxidation of 2-methyl naphthalene (2MN) to 2-methyl-1,4-naphthoquinone (vitamin K3). The chemosensing behaviours of the hybrid ligands were also researched by using UV–vis. technique upon addition of various metal ions such as Na(I), K(I), Cd(II), Co(II), Cu(II), Hg(II), Ni(II), Zn(II), Al(III), Cr(III), Fe(III), and Mn(II) in (1:5 V) ratio in MeOH. The UV–vis. spectra of free hybrid materials show one absorption band at 257 nm possibly due to π–π* transitions in hybrid ligands. While added the metal cations on the ligand dispersions as Cu(II) and Fe(III) (0.1 mM) (1:5 V) ratios in MeOH, a new absorption bands were appeared at different regions in 275–325, 300–375 nm, respectively, because of the complexation between the hybrid materials and the metal ions.

Synthesis, Characterization and Catalytic Properties of Benzylphosphonate-aminethylphosphine-Pd(II), Cu(II), Ru(II) and V(IV) Complexes

The novel 4-(bis((diphenylphosphino)methyl)amino)diethyl-benzylphosphonate (L, ligand) and its Pd(II), Cu(II), Ru(II) and oxo-V(IV) complexes were synthesized under nitrogen atmosphere using Schlenk technique. The ligand and the complexes were characterized with (1H)-31P-NMR, FT-IR, TG/DTA, elemental analysis (C, H, N %), ICP-OES (Metal %), cyclic voltammetry (CV) and photoluminescence techniques. Whereas proton decoupled 31P resonance peak of bis(diphenylphosphinomethyl)amine group was seen at − 8.12 ppm, 31P resonance peak were shifted to 26.82–23.85 ppm in the complexes. It was the confirmation of the coordination of the ligand to the metal centers. Besides, FT-IR stretches and elemental analyses data supported the syntheses of the ligand and its complexes. [Pd(L)Cl2] and [VO(L)(H2O)2]SO4 complexes showed the best catalytic activities with high selectivities in the oxidation of 2-methylnaphthalene (2MN) to 2-methyl-1,4-naphthoquinone (vitamin K3, 2MNQ). Selectivity and conversions were around 55–60% with of 95–99% and respectively for [Pd(L)Cl2] and [VO(L)(H2O)2]SO4 complexes.

2-メチルナフタレンを用いた酸化還元反応 : ビタミン K 誘導体の合成

2-メチルナフタレンを用いた酸化還元反応 : ビタミン K 誘導体の合成

Synthesis of Fe3O4@SiO2@OSi(CH2)3NHRN(CH2PPh2)2PdCl2 type nanocomposite complexes: Highly efficient and magnetically-recoverable catalysts in vitamin K3 synthesis

The synthesis of aminomethylphosphine-metal complexes have opened a new perspective to the catalytic applications of organic compounds. Magnetic Fe3O4 nano-core was synthesized using the closed quartz tube with Teflon cover and microwaved 200°C for 1h with power controlled instrument set to max. 600W. Novel nano-composite supported; Fe3O4@SiO2(CH2)3NHArN(CH2PPh2)2 and Fe3O4@SiO2(CH2)3N(CH2PPh2)2 type bis(diphenylphosphinomethyl)amino ligands and their Pd(II) complexes have been synthesized and characterized with FT-IR, SEM, EDX, TEM, UV–Visible, XRD and TG/DTA techniques. All the complexes were used as heterogeneous catalysts in the oxidation of 2-methyl naphthalene (2MN) to 2-methyl-1, 4-naphthoquinone (vitamin K3, menadione, 2MNQ) in the presence of hydrogen peroxide and acetic acid. Selectivity reached about 55–60% with a conversion of 90–96% using the nano-magnetite supported aminomethylphosphine-Pd(II) complexes. The complexes were very active in three times in the catalytic recycling experiments in five catalytic cycles.

Clariant launches LTS chloride guard catalyst ShiftGuard 200 at Nitrogen + Syngas 2016

The synthesis of aminomethylphosphine-metal complexes have opened a new perspective to the catalytic applications of organic compounds. Magnetic Fe3O4 nano-core was synthesized using the closed quartz tube with Teflon cover and microwaved 200 °C for 1 h with power controlled instrument set to max. 600 W. Novel nano-composite supported; Fe3O4@SiO2(CH2)3NHArN(CH2PPh2)2 and Fe3O4@SiO2(CH2)3N(CH2PPh2)2 type bis(diphenylphosphinomethyl)amino ligands and their Pd(II) complexes have been synthesized and characterized with FT-IR, SEM, EDX, TEM, UV–Visible, XRD and TG/DTA techniques. All the complexes were used as heterogeneous catalysts in the oxidation of 2-methyl naphthalene (2MN) to 2-methyl-1, 4-naphthoquinone (vitamin K3, menadione, 2MNQ) in the presence of hydrogen peroxide and acetic acid. Selectivity reached about 55–60% with a conversion of 90–96% using the nano-magnetite supported aminomethylphosphine-Pd(II) complexes. The complexes were very active in three times in the catalytic recycling experiments in five catalytic cycles.

Selective oxidation of pseudocumene and 2-methylnaphthalene with aqueous hydrogen peroxide catalyzed by γ-Keggin divanadium-substituted polyoxotungstate

The catalytic performance of a γ-Keggin divanadium-substituted phosphotungstate, (Bu4N)4[γ-PW10O38V2(μ-O)(μ-OH)], has been evaluated in the selective oxidation of 1,2,4-trimethylbenzene (pseudocumene, PC) and 2-methylnaphthalene with the green oxidant, 35% aqueous hydrogen peroxide. Under conditions of H2O2 deficiency ([PC]/[H2O2] = 17–22), PC oxidation proceeded with unusually high chemo- and regioselectivity, producing exclusively 2,4,5-trimethylphenol (2,4,5-TMP) and 2,3,5-TMP in a molar ratio of 7.3/1 and a yield of 73% based on the oxidant. Isomeric 2,3,6-trimethylphenol was found in trace amounts. Under conditions of H2O2 excess ([H2O2]/[PC] = 8), 2,3,5-trimethyl-1,4-benzoquinone (TMBQ, vitamin E key intermediate) formed with 41% selectivity at 41% substrate conversion. Atypical regioselectivity was also found in the oxidation of 2-methylnaphthalene which gave predominantly 6-methyl-1,4-naphthoquinone (6-MNQ) rather than isomeric 2-MNQ. The ratio between the isomers could be altered by varying the catalyst and oxidant amounts.

Synthesis of 2-methyl-1,4-naphthoquinone (vitamin K3) using nanostructured gold catalysts in acetic acid and in supercritical carbon dioxide

The synthesis of 2-methyl-1,4-naphthquinone (vitamin K3) by the oxidation of 2-methylnaphthalene and 2-methyl-1-naphthol using nanostructured gold catalysts supported on super-cross-linked polystyrene ((5% Au)/SCP) has been investigated. The temperature effect on the oxidation process is reported. An attempt has been made to replace acetic acid, a common solvent, with supercritical carbon dioxide, an environmentally friendly substance. With supercritical CO2, the selectivity of the process toward 2-methyl-1-naphthol oxidation into the target product remains at a high level (close to 100%) and the substrate conversion is 10–15% higher. In the oxidation of 2-methylnaphthalene, use of supercritical CO2 leads to a dramatic decrease in substrate conversion and target-product selectivity. This is due to the fact that peracetic acid, which is the main oxidizer in this process, does not form under these conditions. The nanostructured gold catalysts are usable in the selective oxidation of 2-methyl-1-naphthol and 2-methylnaphthalene into 2-methyl-1,4-naphthquinone (99 and 58 %, respectively).

Preparation of 2-Methyl-1,4-Naphthoquinone(vitamin K<sub>3</sub>) by Catalytic Oxidation of 2-Methylnaphthalene with Sulfuric Acid as Catalyst

The oxidation of 2-methylnaphthalene(2-MN) to 2-methyl-1,4-naphthoquinone(2-MNQ, Vitamin K3) was accomplished in acetic acid with the application of hydrogen peroxide as oxidant. The yield of 2-MNQ was up to 81.3% when sulfuric acid used as catalyst. The catalyst exhibits excellent substrate conversion and target product selectivity. Different parameters affecting the oxidation of 2-methylnaphthalene with hydrogen peroxide catalyzed by sulfuric acid were described, such as reaction temperature, reaction time, dosage of hydrogen peroxide, and amount of sulfuric acid. Compared with the traditional methods for the preparation of Vitamin K3 with yield of only 30-50%, this method presented could be more effective, economical and ecofriendly.

Manganese(II) naphthenate as effective catalyst for the clean oxidation of 2-methylnaphthalene by hydrogen peroxide

Oxidation of 2-methylnaphthalene (2-MN) with aqueous hydrogen peroxide was conducted in acetic acid. The epoxidation pathway was investigated by increasing the CH3CO3H content and adding manganese(II) naphthenate (MnPc) as catalyst. 2-Methyl-1,4-naphthoquinone was obtained in 75.6% conversion and with 80.0% selectivity under the latter conditions. A probable mechanism in which MnPc catalyzes the oxidation of 2-MN by hydrogen peroxide in acetic acid is proposed.

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, characterization and catalytic properties of SeMCM-41 molecular sieves: oxidation of 2-methylnaphthalene to 2-methyl-1,4-naphthoquinone

Selenium substituted MCM-41(SeMCM-41) samples have been synthesized by using hydrothermal method and characterized by spectroscopic techniques. The oxidation of 2-methylnaphthalene to 2-methyl-1,4-naphthoquinone with hydrogen peroxide in the presence of SeMCM-41 as catalyst in acetic acid is described. The catalyst exhibits excellent substrate conversion and product selectivity. It was found to be a true heterogeneous catalyst as the activity was practically unaffected upon recycling. The highest conversion at highest selectivity has been obtained at 100 °C. Different parameters effecting the oxidation of 2-methylnaphthalene with hydrogen peroxide on SeMCM-41 are described.

Optimization of conditions for preparing vitamin K3 by oxidation of 2-methylnaphthalene with chromium trioxide in acid solutions

Optimal conditions were found for oxidation of 2-methylnaphthalene to 2-methyl-1,4-naphthoquinone with chromium trioxide in sulfuric and acetic acids. The following factors were varied: degree of acid dilution with water, substrate to oxidant weight ratio, and reaction temperature and time. The influence of the rate of reactant mixing and of the reaction temperature on the reaction course was evaluated.

Oxidation of 2‐Methylnaphthalene with Ozone.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Thermal Growth and Decomposition of Methylnaphthalenes

Diesel particulate matter (DPM) has been recognized as carcinogenic due to its respirable sizes and toxic compositions. It is essential to understand its formation mechanisms to effectively reduce DPM emissions. Studies have indicated that resonance stabilize radicals can result in more soot and PAC (polycyclic aromatic compounds) formation in combustion processes. As the largest single polycyclic aromatic constituent in petroleum fuels, 1- and 2-methylnaphthalenes can readily form resonance-stabilized radicals in combustion, and yet the reaction mechanisms are not well understood. In this paper, product formation mechanisms of these compounds are experimentally investigated in a flow reactor. The pyrolysis of 1- and 2-methylnaphthalene was studied from 800 to 1000 degrees C, and the oxidation of 2-methylnaphthalene was studied from 650to 950 degrees C. The PACs were quantified by GC/MS and HPLC, and soot was quantified gravimetrically. Naphthalene is the most abundant product and is formed from methyl loss by H displacement. Isomerization in pyrolytic conditions results in the second most abundant product. The methyl radicals recombine with the reactants to form ethylnaphthalenes and dimethylnaphthalenes. 2-Naphthaldehyde is formed from the oxidation of the naphthylmethyl radicals. 1-Methylnaphthalene is of slightly higher reactivity in comparison to its isomer. The experimental results indicate that the PAC formation from the pyrolysis and oxidation of the two methylnaphthalenes are likely to be governed by similar mechanisms. The lack of carbon dimerization products in significant quantities may be due to their further growth into soot.

Oxidation of 2-methylnaphthalene with ozone

In the oxidation of 2-methylnaphthalene with ozone in acetic acid, the oxidant reacts mainly at the double bonds of the substituted aromatic ring to give peroxy compounds. In the presence of cobalt diacetate and sodium bromide, oxidation of the 2-methyl group occurs with formation of 2-naphthoic acid. The major product in the oxidation of 2-methylnaphthalene with ozonated transition metal compounds is 2-methyl-1,4-naphthoquinone.

Selective oxidation of aromatic compounds with dioxygen and peroxides catalyzed by phthalocyanine supported catalysts

This article summarizes our research in catalytic oxidation on the design and study of supported metallophthalocyanine catalysts. The catalytic properties of these materials were studied in the oxidation of 2-methylnaphthalene (2MN) to 2-methyl-1,4-naphthoquinone (Vitamin K 3, VK 3), 2,3,6-trimethylphenol (TMP) to trimethyl-1,4-benzoquinone (precursor of Vitamin E) and in the epoxidation of olefins. Iron tetrasulfophthalocyanine (FePcS) covalently grafted in the dimeric form yielded catalyst more active and selective that those containing monomeric species but suffered from a lack of stability transforming into less selective monomer complexes during catalysis. The stabilization of supported dimer form by covalent link of two adjacent phthalocyanine molecule through appropriate diamine spacer provided more selective and stable catalysts. Trimethyl-1,4-benzoquinone was obtained with 87% yield at 97% conversion of TMP. More demanding oxidation of 2MN afforded 45% yield of VK 3. Particular emphasis is placed on the mechanistic aspects of these oxidations using two mechanistic probes, 2-methyl-1-phenylpropan-2-yl hydroperoxide (MPPH) to distinguish between homolytic versus heterolytic cleavage of O–O bond during the formation of active species and thianthrene 5-oxide (SSO) to evaluate nucleophilic versus electrophilic character of formed active species. To illustrate a versatility of the phthalocyanine-based supported catalysts we prepared a novel phthalocyanine complex with eight triethoxysylil substituents which can be directly anchored to the silica without any modification of the silica support. This new catalyst shows good catalytic activity in epoxidation of olefins by dioxygen in the presence of isobutyraldehyde. The same catalytic system was also active in the oxidation of phenols to biphenols with 86% yields. This catalytic system is complementary to previous one that selectively oxidizes phenols to quinones. An appropriate choice of the reaction conditions allows selective oxidation either to quinones or to biaryl compounds.

A novel and environmentally benign selective route for Vitamin K 3 synthesis

The oxidation of 2-methylnaphthalene was carried out in acetic acid with aqueous hydrogen peroxide. 2-Methyl-1,4-naphthoquinone was obtained in a selectivity of nearly ≥90% at 100 °C for 3 h. The reaction has been studied by varying different parameters like concentration of hydrogen peroxide, strength of acetic acid, molar ratio of 2-methylnaphthalene to hydrogen peroxide, reaction temperature and time. Compared to the conventional preparation of Vitamin K 3, this method could be economical and ecofriendly as the use of mineral acid and chromium salts are avoided.