Oxidation of fine chemicals by iron based and metal-free catalysis

The catalytic oxidation by using transition metal complexes offers attractive opportunities for industrial applications following environmentally benign manufacturing processes. However, the number of such catalytic methods has substantially decreased. In this thesis, we developed and utilized three iron based catalysts (FeIII/thymine-1-acetic acid, FeIII/Phenanthroline, and FeII/Nmethylimidazole) and one organic catalysts (1,2-Di(1-naphthyl)-1,2-ethanediamine (NEDA)). The iron/THA catalyst (iron/thymine-1-acetic acid) is efficiently capable of oxidizing both primary and secondary aliphatic alcohols into their corresponding carbonyl compounds, acids and ketones. The system can also oxidize alkanes with different steric and electronic environment. We also presented a new method for the oxidation of benzylic and aliphatic primary and secondary alcohols using iron-based catalyst, which is [Fe(phen)2Cl2]NO3 (iron/Phenanthroline), with hydrogen peroxide as a terminal oxidant. The easily accessible catalyst (iron/N-methylimidazole) was developed to form dehydrogenative coupling reaction between benzaldehydes and styrenes. The CH activation to produce α,β unsaturated ketones has been also developed. The organic (metal-free) catalyst (1,2-Di(1-naphthyl)-1,2-ethanediamine (NEDA)) has shown to be an efficient catalyst for the oxidation of secondary alcohols with t-BuOOH as a terminal oxidant. Under mild reaction conditions, a secondary alcohol is converted into its corresponding ketone.Katalyysi on tärkeä kemian ala ja sitä hyödynnetään laajasti muun muassa teollisuudessa sekä ympäristö- ja biotieteissä. Erityisesti katalyyttistä hapetusta käytetään hyväksi ratkaistaessa lääketeollisuuden ja kemikaalien tuotannon taloudellisia ja ympäristöllisiä ongelmia. Tämä tapahtuu kehittämällä tehokkaita, selektiivisiä ja ympäristöllisesti kestäviä synteesiprosesseja. Näissä prosesseissa käytetyt katalyytit voivat kuitenkin olla kalliita tai myrkyllisiä. Tässä väitöskirjatyössä kehitettiin kolme rautayhdisteisiin perustuvaa hapetuskatalyyttiä sekä metalliton katalyysimenetelmä, joita on mahdollista hyödyntää hienokemikaalien valmistuksessa

Catalytic behaviour of the Cu(i)/L/TEMPO system for aerobic oxidation of alcohols - a kinetic and predictive model

Here, we disclose a new copper(i)-Schiff base complex series for selective oxidation of primary alcohols to aldehydes under benign conditions. The catalytic protocol involves 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO), N-methylimidazole (NMI), ambient air, acetonitrile, and room temperature. This system provides a straightforward and rapid pathway to a series of Schiff bases, particularly, the copper(i) complexes bearing the substituted (furan-2-yl)imine bases N-(4-fluorophenyl)-1-(furan-2-yl)methanimine (L2) and N-(2-fluoro-4-nitrophenyl)-1-(furan-2-yl)methanimine (L4) have shown excellent yields. Both benzylic and aliphatic alcohols were converted to aldehydes selectively with 99% yield (in 1-2 h) and 96% yield (in 16 h). The mechanistic studies via kinetic analysis of all components demonstrate that the ligand type plays a key role in reaction rate. The basicity of the ligand increases the electron density of the metal center, which leads to higher oxidation reactivity. The Hammett plot shows that the key step does not involve H-abstraction. Additionally, a generalized additive model (GAM, including random effect) showed that it was possible to correlate reaction composition with catalytic activity, ligand structure, and substrate behavior. This can be developed in the form of a predictive model bearing in mind numerous reactions to be performed or in order to produce a massive data-set of this type of oxidation reaction. The predictive model will act as a useful tool towards understanding the key steps in catalytic oxidation through dimensional optimization while reducing the screening of statistically poor active catalysis.Peer reviewe

Synthesis and Characterization of Novel Phyto-Mediated Catalyst, and Its Application for a Selective Oxidation of (VAL) into Vanillin under Visible Light

Here, we report an efficient and highly selective oxidation of lignin model substrate using phyto-mediated ZnFe2O4 nanoparticle using Boswellia carterii extract. The nanocatalyst with an average size of 8 nm showed excellent photocatalytic activity of the synthesized carbonyl containing products under visible light irradiation. The catalytic activity and selectivity towards oxidation of vanillyl alcohol to vanillin with selectivity up to 99% at conversion over 98% and turn-over frequency values up to 1600 h−1 were obtained in the presence of H2O2 and base. The cubic spinel nano-ZnFe2O4 catalyst was characterized by powder-XRD, FESEM, HR-TEM and Mössbauer analysis. The demonstrated catalyst was robust and stable under the reaction conditions. Furthermore, it was easy to be separated from the reaction mixture and be reused for subsequent reactions up to 5 times without significant reactivity or selectivity loss

Synthesis and Characterization of Novel Phyto-Mediated Catalyst, and Its Application for a Selective Oxidation of (VAL) into Vanillin under Visible Light

Here, we report an efficient and highly selective oxidation of lignin model substrate using phyto-mediated ZnFe2O4 nanoparticle using Boswellia carterii extract. The nanocatalyst with an average size of 8 nm showed excellent photocatalytic activity of the synthesized carbonyl containing products under visible light irradiation. The catalytic activity and selectivity towards oxidation of vanillyl alcohol to vanillin with selectivity up to 99% at conversion over 98% and turn-over frequency values up to 1600 h−1 were obtained in the presence of H2O2 and base. The cubic spinel nano-ZnFe2O4 catalyst was characterized by powder-XRD, FESEM, HR-TEM and Mössbauer analysis. The demonstrated catalyst was robust and stable under the reaction conditions. Furthermore, it was easy to be separated from the reaction mixture and be reused for subsequent reactions up to 5 times without significant reactivity or selectivity loss

Elemental Contamination in Indoor Floor Dust and Its Correlation with PAHs, Fungi, and Gram plus /-Bacteria

In this study, we performed elemental analysis for floor dust samples collected in Jordanian microenvironments (dwellings and educational building). We performed intercorrelation and cluster analysis between the elemental, polyaromatic hydrocarbon (PAH), and microorganism concentrations. In general, the educational building workshops had the highest elemental contamination. The age of the dwelling and its occupancy played a role on the elemental contamination level: older and more occupied dwellings had greater contamination. The elemental contamination at a dwelling entrance was observed to be higher than in the living room. We found exceptionally high concentrations for Fe and Mn in the educational workshop and additionally, Hg, Cr, and Pb concentrations exceeded the limits set by the Canadian Council of Ministers of the Environment. According to the cluster analysis, we found three major groups based on location and contamination. According to the enrichment factor (EF) assessment, Al, Co, Mn, Ti, and Ba had EF 40 (i.e., extremely enriched). In contrast, Ca and P were geogenically enriched. Furthermore, significant Spearman correlations indicated nine subgroups of elemental contamination combined with PAHs and microbes.Peer reviewe

Nano-Magnetic NiFe2O4 and Its Photocatalytic Oxidation of Vanillyl Alcohol—Synthesis, Characterization, and Application in the Valorization of Lignin

Here, we report on a phyto-mediated bimetallic (NiFe2O4) preparation using a Boswellia carterii extract, which was characterized by XRD, FT-IR, TGA, electron microscopy, magnetic spectroscopy, and Mössbauer spectroscopy measurements. The prepared nano-catalysts were tested for oxidation of lignin monomer molecules—vanillyl alcohol and cinnamyl alcohol. In comparison with previously reported methods, the nano NiFe2O4 catalysts showed high photocatalytic activity and selectivity, under visible light irradiation with a nitroxy radical initiator (2,2,6,6-tetramethylpiperidinyloxy or 2,2,6,6-tetramethylpiperidine 1-oxyl; TEMPO) at room temperature and aerobic conditions. The multifold advantages of the catalyst both in terms of reduced catalyst loading and ambient temperature conditions were manifested by higher conversion of the starting material

Contamination of plants, soil, and building stones at a Roman heritage archaeological site in an urban area

Some cultural heritage sites in Jordan are in urban areas being exposed to anthropogenic pollution. Therefore, it is important to evaluate the contamination at these sites to protect them. Here, we considered a Roman archeological site (Nymphaeum) situated in Amman. The contamination in soil, plants, and building stones did not show spatial distribution within the site. The contamination was the highest in soil (heavy metals 10(4) -10(7) ppb and sulfur similar to 3.5x10(6) ppb) whereas in plants was the least for Cr (similar to 400 ppb) and in building stones it was the least for Cu (similar to 860 ppb). The highest contamination in plants and building stones was found for Al (similar to 5x10(4) and similar to 6.2x10(5) ppb respectively). The sulfur content in plants (similar to 7.6x10(5) ppb) was higher than that in the building stones (similar to 2.3x10(5) ppb). The heavy metals and sulfur contamination in the building stones were lower than what was reported elsewhere outside Jordan.Peer reviewe

Elemental Contamination in Indoor Floor Dust and Its Correlation with PAHs, Fungi, and Gram+/− Bacteria

In this study, we performed elemental analysis for floor dust samples collected in Jordanian microenvironments (dwellings and educational building). We performed intercorrelation and cluster analysis between the elemental, polyaromatic hydrocarbon (PAH), and microorganism concentrations. In general, the educational building workshops had the highest elemental contamination. The age of the dwelling and its occupancy played a role on the elemental contamination level: older and more occupied dwellingshad greater contamination. The elemental contamination at a dwelling entrance was observed to be higher than in the living room. We found exceptionally high concentrations for Fe and Mn in the educational workshop and additionally, Hg, Cr, and Pb concentrations exceeded the limits set by the Canadian Council of Ministers of the Environment. According to the cluster analysis, we found three major groups based on location and contamination. According to the enrichment factor (EF) assessment, Al, Co, Mn, Ti, and Ba had EF 40 (i.e., extremely enriched). In contrast, Ca and P were geogenically enriched. Furthermore, significant Spearman correlations indicated nine subgroups of elemental contamination combined with PAHs and microbes

Elemental Contamination in Indoor Floor Dust and Its Correlation with PAHs, Fungi, and Gram+/− Bacteria

In this study, we performed elemental analysis for floor dust samples collected in Jordanian microenvironments (dwellings and educational building). We performed intercorrelation and cluster analysis between the elemental, polyaromatic hydrocarbon (PAH), and microorganism concentrations. In general, the educational building workshops had the highest elemental contamination. The age of the dwelling and its occupancy played a role on the elemental contamination level: older and more occupied dwellingshad greater contamination. The elemental contamination at a dwelling entrance was observed to be higher than in the living room. We found exceptionally high concentrations for Fe and Mn in the educational workshop and additionally, Hg, Cr, and Pb concentrations exceeded the limits set by the Canadian Council of Ministers of the Environment. According to the cluster analysis, we found three major groups based on location and contamination. According to the enrichment factor (EF) assessment, Al, Co, Mn, Ti, and Ba had EF 40 (i.e., extremely enriched). In contrast, Ca and P were geogenically enriched. Furthermore, significant Spearman correlations indicated nine subgroups of elemental contamination combined with PAHs and microbes

A di-iron(III) mu-oxido complex as catalyst precursor in the oxidation of alkanes and alkenes

The oxido-bridged diiron(III) complex [Fe-2(mu-O)(mu-OAc)(DPEAMP)(2)](OCH3) (1), based on a new unsymmetrical ligand with an N4O donor set, viz. [2-((bis(pyridin-2-ylmethyl)amino)methyl)-6-((ethylamino)methyl)-4-meth-ylphenol (HDPEAMP)], has been prepared and characterized by spectroscopic methods and X-ray crystallog-raphy. The crystal structure of the complex reveals that each Fe(III) ion is coordinated by three nitrogen and three oxygen donors, two of which are the bridging oxido and acetate ligands. Employing H2O2 as a terminal oxidant, 1 is capable of oxidizing a number of alkanes and alkenes with high activity. The catalytic oxidation of 1,2-dimethylcyclohexane results in excellent retention of configuration. Monitoring of the reaction of 1 with H2O2 and acetic acid in the absence of substrate, using low-temperature UV-Vis spectroscopy, suggests the in situ formation of a transient Fe(III)(2)-peroxido species. While the selectivity and nature of oxidation products implicate a high-valent iron-oxido complex as a key intermediate, the low alcohol/ketone ratios suggest a simultaneous radical-based process.Peer reviewe