Manganese Catalysed Dehydrogenative Synthesis of Urea Derivatives and Polyureas

Urea derivatives are prevalent intermediates in the synthesis of resin precursors, dyes, agrochemicals, and pharmaceutical drugs. Furthermore, polyureas are useful plastics with applications in coating, adhesive, and biomedical industries and have a current annual market of USD 885 million. However, the conventional methods for the synthesis of urea derivatives and polyureas involve toxic reagents such as (di)isocyanates, phosgene, CO, and azides. We present here the synthesis of (poly)ureas using much less toxic reagents - (di)amines, and methanol via a catalytic dehydrogenative coupling process. The reaction is catalyzed by a pincer complex of an earth-abundant metal, manganese, and liberates H2 gas, valuable by itself, as the only by-product making the overall process atom-economic, and sustainable. A broad variety of symmetrical, and unsymmetrical urea derivatives and polyureas have been synthesized in moderate to quantitative yields using this catalytic protocol. Mechanistic insights have also been provided using experiments and DFT computation suggesting that the reaction proceeds via an isocyanate intermediate.

Influence of Storage Time and Temperature on the Toxicity, Endocrine Potential, and Migration of Epoxy Resin Precursors in Extracts of Food Packaging Materials

The aim of the present study was to establish a standard methodology for the extraction of epoxy resin precursors from several types of food packages (cans, multi-layered composite material, and cups) with selected simulation media (distilled water, 5% ethanol, 3% dimethyl sulfoxide, 5% acetic acid, artificial saliva) at different extraction times and temperatures (factors). Biological analyses were conducted to determine the acute toxicity levels of the extracts (with Vibrio fischeri bacteria) and their endocrine potential (with Saccharomyces cerevisiae yeasts). In parallel, liquid chromatography-tandem mass spectrometry was performed to determine levels of bisphenol A diglycidyl ether (BADGE), bisphenol F diglycidyl ether (mixture of isomers, BFDGE), ring novolac glycidyl ether (3-ring NOGE), and their derivatives. The variation induced by the different experimental factors was statistically evaluated with analysis of variance simultaneous component analysis (ASCA). Our findings demonstrate the value of using a holistic approach to best partition the effects contributing to the end points of these assessments, and offer further guidance for adopting such a methodology, thus being a broadly useful reference for understanding the phenomena related to the impacts of food packaging materials on quality for long- and short-term storage, while offering a general method for analysis.

A New Route for Low Pressure and Temperature CWAO: A PtRu/MoS2_Hyper-Crosslinked Nanocomposite

PtRu/MoS2 nanoparticles (NPs) (PtRu alloy partially coated by one-layer MoS2 nanosheets) were prepared through a ‘wet chemistry’ approach. The obtained NPs were directly embedded, at 5 parts per hundred resin/rubber (phr) loading, in a poly (divinylbenzene-co-vinyl benzyl chloride) hyper-crosslinked (HCL) resin, synthesized via bulk polymerization of the resin precursors, followed by conventional FeCl3 post-crosslinking. The obtained HCL nanocomposites were characterized to evaluate the effect of the NPs. It shows a high degree of crosslinking, a good dispersion of NPs and a surface area up to 1870 ± 20 m2/g. The catalytic activity of the HCL nanocomposite on phenol wet air oxidation was tested at low air pressure (Pair = 0.3 MPa) and temperature (T = 95 °C), and at different phenol concentrations. At the lower phenol concentration, the nanocomposite gives a total organic carbon (TOC) conversion of 97.1%, with a mineralization degree of 96.8%. At higher phenol concentrations, a phenol removal of 99.9%, after 420 min, was achieved, indicating a quasi-complete depletion of phenol, with a TOC conversion of 86.5%, corresponding to a mineralization degree of 84.2%. Catalyst fouling was evaluated, showing good reusability of the obtained nanocomposite.

Carbon beads with a well-defined pore structure derived from ion-exchange resin beads

Carbon beads with a well-defined micropore structure and excellent CO2 capture ability were obtained by carbonization of K-exchanged cation exchange resin precursors.

Towards a sustainable electrochemical activation for recycling CO2: synthesis of bis-O-alkylcarbamates from aliphatic and benzyl diamines

Optimized conditions for carbamate synthesis with activated CO2 are potentially applicable to sustainable large scale manufacturing of key polymeric resin precursors.

Novel synthesis of dispersed molybdenum and nickel phosphides from thermal carbonization of metal- and phosphorus-containing resins

New (Mo,Ni),P-containing resin precursors to dispersed MoP and Ni2P nanoparticles.

Resins Materials as Alternative Insert for the Fabrication of Micro Structured Surfaces by Micro Injection Moulding

Micro injection moulding is a key technology for mass-production of micro structured surfaces, such as optical and microfluidic devices. The manufacturing of a microstructured master mould with traditional technologies poses challenges about durability, accuracy and high - volume production. This paper introduces a new approach to realize micro mould inserts in a fast and economical way. Suitable engineered materials as alternative inserts to the metallic one are proposed exploiting the following new strategy: a thermosetting epoxy resin from renewable sources was synthesized and used to realize the mould insert via casting. The initial low viscosity of the liquid epoxy resin precursors allows the achievement of a high fidelity replica of different micro structures and provides an inexpensive and convenient route for rapidly duplicate master mould. A staggered harringbone (SHM) micro-mixer geometry was replicated and the epoxy based resin insert withstood 900 moulding cycles showing good features replication and durability.