Scalable and selective deuteration of (hetero)arenes

Isotope labelling, particularly deuteration, is an important tool for the development of new drugs, specifically for identification and quantification of metabolites. For this purpose, many efficient methodologies have been developed that allow for the small-scale synthesis of selectively deuterated compounds. Due to the development of deuterated compounds as active drug ingredients, there is a growing interest in scalable methods for deuteration. The development of methodologies for large-scale deuterium labelling in industrial settings requires technologies that are reliable, robust and scalable. Here we show that a nanostructured iron catalyst, prepared by combining cellulose with abundant iron salts, permits the selective deuteration of (hetero)arenes including anilines, phenols, indoles and other heterocycles, using inexpensive D2O under hydrogen pressure. This methodology represents an easily scalable deuteration (demonstrated by the synthesis of deuterium-containing products on the kilogram scale) and the air- and water-stable catalyst enables efficient labelling in a straightforward manner with high quality control.

Heterogeneous Iron Catalyst Fe/SBA-15 towards sp3 C-O bond activation in the absence of base and additive

A heterogeneous iron-catalyzed (8wt%Fe/SBA-15) mediated direct alkylation of benzyl alcohol with aryl boronic acid in the absence of base and additive via C-O bond activation is demonstrated. This catalyst system led to an efficient Friedel-crafts alkylation reaction. The acidic site in the catalyst system had been confirmed by NH3-TPD, which shows the presence of three different acidic sites viz., weak, moderated, and strong acid sites. The catalyst showed five times recyclable ability.

Atom-economic amide synthesis by iron-substituted polyoxometalate catalyst

We report an efficient and economical amidation strategy by using polyoxometalate-based iron catalyst afford the corresponding amide products in good yields. All of the aliphatic, aromatic and heterocyclic substrates are...

Heterogeneous Iron Catalyst Fe/SBA-15 towards sp3 C-O bond activation in the absence of base and additive

A heterogeneous iron-catalyzed (8wt%Fe/SBA-15) mediated direct alkylation of benzyl alcohol with aryl boronic acid in the absence of base and additive via C-O bond activation is demonstrated. This catalyst system led to an efficient Friedel-crafts alkylation reaction. The acidic site in the catalyst system had been confirmed by NH3-TPD, which shows the presence of three different acidic sites viz., weak, moderated, and strong acid sites. The catalyst showed five times recyclable ability.

Photo-Fenton Oxidative System for Removing Tartrazine Yellow Dye in Aqueous Medium Using Y-fe Zeolite As Catalyst

The synthesis and application of heterogeneous solid catalysts in Fenton-type processes have been shown to be a promising alternative for the removal of hazardous pollutants. In this context, the aim of this study was to prepare and characterize a heterogeneous solid iron catalyst supported on zeolite Y for the degradation of yellow food coloring tartrazine (TY). The catalyst was produced through humid ion exchange and characterized by the physisorption of N2, XRD, SEM, TEM and EDX. The efficiency of the catalyst was evaluated through the degradation of tartrazine yellow dye in a batch regime, and the influence of some of the main operational parameters was also evaluated. The characterizations confirmed the presence of iron on the surface of zeolite Y and the increase in the specific area and pore volume after ion exchange. The catalyst used in the photo-Fenton system was extremely efficient, with a removal of approximately 98% in 120 min in the experimental conditions: [TY]0 = 10 mg/L, [H2O2]0 =200 g/L, Y-Fe dosage=1.5 g/L and pH= 3.0. It was possible to recover the catalyst and use it in five reuse cycles, showing its stability and potential application of this catalyst in heterogeneous photo-Fenton systems.

The Direct Growth of Carbon Nanotubes and Its Substrate Dependence

<p>The unique combination of light weight, small dimensions, structural diversity, excellent mechanical strength and remarkable electronic properties make carbon nanotubes an attractive field of discovery for a wide range of applications, from reinforcing materials to molecular sensing. The immediate problem is in reliably and reproducibly fabricating carbon nanotubes and nanotube arrays with a certain exclusive structure. The reason for this is the large number of parameters integral to nanotube growth. This thesis describes the effect of several synthesis parameters - including temperature, catalyst, and water addition - on the growth of carbon nanotubes by a thermal chemical vapour deposition method. In all instances, multi-walled nanotubes were the only carbon nanotube products observed. The chemical vapour deposition method employed here involves hexane as a volatile carbon precursor and ferrocene as a floating catalyst. The hexane is introduced into the system by passing a stream of nitrogen carrier gas through a bubbler containing the carbon precursor, while the ferrocene catalyst is positioned inside the working tube where it can evaporate gradually. The products of this method are large, vertically aligned arrays of clean multi-walled nanotubes. The second part of this thesis describes the role of the supporting layer in affecting the growth of these extended nanotube arrays. A number of substrates have been examined - both conducting and non-conducting - and the products from these were analysed. It was found that all non-conductive, metal oxide substrates used - these included quartz, alumina, glazed porcelain, Pythagoras, and also fluorite - produced extended fields of carbon nanotubes. Conversely, many conductive substrates - including nickel, molybdenum, glassy carbon, highly ordered pyrolitic graphite and nickel-iron-silicon metal alloys - produce only small amounts of carbon nanotubes. This difference is likely caused by the deactivation of the iron catalyst at high temperature due to diffusion into the substrate surface.</p>

The Direct Growth of Carbon Nanotubes and Its Substrate Dependence

<p>The unique combination of light weight, small dimensions, structural diversity, excellent mechanical strength and remarkable electronic properties make carbon nanotubes an attractive field of discovery for a wide range of applications, from reinforcing materials to molecular sensing. The immediate problem is in reliably and reproducibly fabricating carbon nanotubes and nanotube arrays with a certain exclusive structure. The reason for this is the large number of parameters integral to nanotube growth. This thesis describes the effect of several synthesis parameters - including temperature, catalyst, and water addition - on the growth of carbon nanotubes by a thermal chemical vapour deposition method. In all instances, multi-walled nanotubes were the only carbon nanotube products observed. The chemical vapour deposition method employed here involves hexane as a volatile carbon precursor and ferrocene as a floating catalyst. The hexane is introduced into the system by passing a stream of nitrogen carrier gas through a bubbler containing the carbon precursor, while the ferrocene catalyst is positioned inside the working tube where it can evaporate gradually. The products of this method are large, vertically aligned arrays of clean multi-walled nanotubes. The second part of this thesis describes the role of the supporting layer in affecting the growth of these extended nanotube arrays. A number of substrates have been examined - both conducting and non-conducting - and the products from these were analysed. It was found that all non-conductive, metal oxide substrates used - these included quartz, alumina, glazed porcelain, Pythagoras, and also fluorite - produced extended fields of carbon nanotubes. Conversely, many conductive substrates - including nickel, molybdenum, glassy carbon, highly ordered pyrolitic graphite and nickel-iron-silicon metal alloys - produce only small amounts of carbon nanotubes. This difference is likely caused by the deactivation of the iron catalyst at high temperature due to diffusion into the substrate surface.</p>

The Potential Use of Raw Iron Ore in Fischer-Tropsch Synthesis

Fischer-Tropsch (FT) synthesis has been studied in the literature as a greener pathway to cleaner and sustainable hydrocarbons production. However, the cost to upscale laboratory FT formulations to pilot scale is significantly expensive. This work proposes a cheaper and scalable low-temperature FT modified iron ore catalyst that is mechanically suited for fixed bed reactors. The mechanical strength reported in this investigation was three times more than commercial alumina spherical pellets and, therefore, suitable for pilot scale scenarios. A manufacturing cost analysis of iron ore was estimated to be US$38.45/kg using the CatCost model, and the conventionally prepared iron catalyst was US$71.44/kg using the same model. The manufacturing cost estimations of modified iron ore were found to be 46% cheaper than a conventional commercial iron catalyst. The catalytic performance of the modified iron ore catalyst showed a CO conversion of 72.1% ±4.24, with WGS and C5+ selectivity 48.6% ±1.96 and 83.2% ± 5.24, respectively. These findings were comparable (both in CO conversion and product selectivity) to the ones reported by other researchers.

Mechanical Properties and Characterization of Epoxy Composites Containing Highly Entangled As-Received and Acid Treated Carbon Nanotubes

Huntsman–Merrimack MIRALON® carbon nanotubes (CNTs) are a novel, highly entangled, commercially available, and scalable format of nanotubes. As-received and acid-treated CNTs were added to aerospace grade epoxy (CYCOM® 977-3), and the composites were characterized. The epoxy resin is expected to infiltrate the network of the CNTs and could improve mechanical properties. Epoxy composites were tested for flexural and viscoelastic properties and the as-received and acid treated CNTs were characterized using Field-Emission Scanning and Transmission Electron Microscopy, X-Ray Photoelectron Spectroscopy, and Thermogravimetric Analysis. Composites containing 0.4 wt% as-received CNTs showed an increase in flexural strength, from 136.9 MPa for neat epoxy to 147.5 MPa. In addition, the flexural modulus increased from 3.88 GPa for the neat epoxy to 4.24 GPa and 4.49 GPa for the 2.0 wt% and 3.0 wt% as-received CNT/epoxy composites, respectively. FE-SEM micrographs indicated good dispersion of the CNTs in the as-received CNT/epoxy composites and the 10 M nitric acid 6 h treatment at 120 °C CNT/epoxy composites. CNTs treated with 10 M nitric acid for 6 h at 120 °C added oxygen containing functional groups (C–O, C=O, and O=C–O) and removed iron catalyst present on the as-received CNTs, but the flexural properties were not improved compared to the as-received CNT/epoxy composites.