Chimia最新文献

Catalytic conversions in fine-chemical and pharmaceutical production are increasingly performed in trickle-bed rectors. Optimisation of these processes is usually based on end of pipe measurement made at specific residence times. This process is both time-consuming and the data sometimes challenging to interpret. In the present work, operando nuclear magnetic resonance (NMR) techniques both at the scale of the whole bed (global) and spatially resolved within the bed (local) are used to gain new insights into the catalytic conversion process under reaction conditions. Spatially resolved spectroscopic and diffusion-T2-relaxation (D-T2) methods interrogate local differences in chemical conversion and selectivity, and mass transport (molecular self-diffusion) respectively, thereby providing valuable information for process simulation models. This capability is demonstrated using the continuous flow three phase (gas-liquid-solid) hydrogenation of benzonitrile over a fixed bed of 0.5 wt% Pd/Al2O3 catalyst pellets yielding toluene and benzylamine. Global 1H spectroscopic and D-T2 were used to monitor chemical conversion and the approach to steady state; these were subsequently followed by spatially resolved 1H spectra and spatially resolved D-T2 correlations to examine the local differences in axial conversion and selectivity of the catalyst bed packing. At steady-state a global conversion of 63% was achieved with 65% and 25% selectivity to benzylamine and toluene respectively. Heterogeneities in the local (axial) conversion and selectivity differed by 31% along the total catalyst bed length. These techniques should be applicable to many three-phase heterogeneous catalytic systems provided that the T2 relaxation time of the reactants and products is not prohibitively small.

There is a constant pressure in industry to move away from platinum group metals (PGM) and achieve more environmentally friendly and sustainable production processes in the future. Recently developed Mn-based catalysts offer an interesting opportunity to complement established catalysts based on Ru. In this article, recent achievements in the field are highlighted and recent achievements in the collaboration of Solvias AG with the group of Prof. M. Clarke towards the implementation of these catalysts on industrial scale are outlined.

Aryl azoles can be found in numerous active pharmaceutical ingredients (APIs). Milvexian is a Factor Xia inhibitor currently in phase III for the treatment of thrombotic events containing an ortho-substituted 1-aryl-1H-1,2,3-triazole moiety. During the process development of Milvexian, we assessed multiple approaches for the preparation of 4-chloro-1,2,3-triazole, intermediate 1. In this review article, we will detail how we initiated several academic collaborations to speed up the selection of the best synthesis for commercial manufacturing. Ultimately, those results not only helped us to achieve our goal but yielded general methodologies for the functionalization of azoles that extended even beyond our initial scope.

A telescoped, two-step synthesis was investigated by applying Quality by Design principles. A kinetic model consisting of 12 individual reactions was successfully established to describe the synthesis and side reactions. The resulting model predicts the effects of changes in process parameters on total yield and quality. Contour plots were created by varying process parameters and displaying the model predicted process response. The areas in which the process response fulfils predetermined quality requirements are called design spaces. New ranges for process parameters were explored within these design spaces. New conditions were found that increased the robustness of the process and allowed for a considerable reduction of the used amounts of a reagent. Further optimizations, based on the newly generated knowledge, are expected. Improvements can either be direct process improvements or enhancements to control strategies. The developed strategies can also be applied to other processes, enhancing upcoming and preexisting research and development efforts.

The growth of Africa as a major gold (Au) exporter can not only strengthen economic ties with other parts of the world, but also lead to solutions to global industrial challenges, and the only way to stop gold smuggling out of gold-producing African countries seems to be having multiple refineries in Africa, for which developing gold-producing African countries might need technological assistance provided by a more developed country, especially Switzerland. In this Note, the chemistry of gold mining was discussed, and the idea is conveyed that if aqua regia is used as a main reagent in both gold mining and the electrolytic refinement of gold, then the two systems of gold mining and gold refining can be coupled industrially and geographically, and such a coupling can facilitate the growth of home-grown gold refineries in gold-producing African countries. It is also discussed that with Swiss companies finding it economical to properly use aqua regia in Africa as described, a win-win African-Swiss cooperation will be established that will benefit both the Swiss companies and gold-producing African countries. Further, it is concluded that the addressed cooperation will be accompanied by four of the seventeen goals called 'Sustainable Development Goals' by the United Nations.