Continuous Flow Asymmetric Transfer Hydrogenation with Long Catalyst Lifetime and Low Metal Leaching

Homogenous iridium complexes with asymmetric ligands and different tether lengths have been solid‐supported and prepared in multi‐gram quantities. Packed in a fixed‐bed, they have been used in continuous flow for up to 120 hours in the asymmetric transfer hydrogenation of APs in 2‐propanol to make 1‐phenethyl alcohols in > 95 % conversion and ee. The CsDPEN ligand and C5 tether showed higher performance than TsDPEN and the C14 tether, whilst the ketone feed concentration and reaction temperature were optimized to enable the catalyst to be used at 5 mol‐% loading with a residence time of 39 minutes. The total amount iridium leaching of from the support during sustained operation was 58–147 ppm. The flow system gives higher catalyst turnover numbers than the related batch reactions, but the nature and concentration of the base were found to influence strongly the catalyst's performance, with the finding that triethylamine maintains high enantioselectivity but slowly deactivates the catalyst, whilst potassium tert‐butoxide does the opposite. The utility of the system is shown in the high ee's and good conversions achieved for a range of aryl alcohols

Recyclable glucose-derived palladium(0) nanoparticles as in situ-formed catalysts for cross-coupling reactions in aqueous media

In situ-generated, glucose-derived palladium(0) nanoparticles were shown to be convenient and effective catalysts for aqueous Mizoroki-Heck, Sonogashira and Suzuki-Miyaura cross-coupling reactions. The addition of only 4-10 mol glucose to the reaction mixture lead to a significant increase in yield of the desired products in comparison to processes that omitted the renewable sugar. Interestingly, the Mizoroki-Heck reaction was observed to proceed in good yield even as the reaction reached acidic pH levels. Extensive analysis of the size and morphology of the in situ-formed palladium nanoparticles using advanced analytical techniques showed that the zero valent metal was surrounded by hydrophilic hydroxyl groups. The increased aqueous phase affinity afforded by these groups allowed for facile recycling of the catalyst

Progression of drip irrigation and fertigation in cotton across the globe and its future perspectives for sustainable agriculture: an overview

Abstract Sustainable use and efficient management of water as an agricultural input have become a major global challenge. Agriculture consumes 70% of global freshwater sources, of which cotton alone is consuming 11%, and thus necessitates for appropriate water and fertilizer savvy strategies such as drip irrigation and fertigation. Drip irrigation has slowly progressed from being a novelty in 1960s to be now an accepted method among farmers. However, documented information on progress of drip fertigation in cotton over the last two decades is little available. In this global review, we have summarized a total of 124 studies not only from developed countries like China, USA but also from developing countries like India, and the Middle East showcasing the adoption and practice of drip fertigation in major cotton growing regions over the last 20 years, besides its role in improving productivity and rational resource use in a sustainable manner. Present findings reveal that drip fertigation could save 20–30% fertilizer and around 50–60% of water besides improving cotton yield. However, despite distinguished advantages, its adoption is limited in most of developing countries with the main impediment being the high initial investment. The area in India alone can be increased 15 folds as compared to present acreage under drip, which can translate into huge saving of water and fertilizer resources. Since, the long-term benefits can help to compensate for the initial cost, farmer friendly policies are required to popularize this technology. While providing quantitative evidence of the significant water and fertilizer savings achieved through drip fertigation, this study could significantly contribute to the existing body of knowledge besides helping to reduce water footprint of cotton across the globe

Tsuji–Trost \u3ci\u3eN\u3c/i\u3e-Allylation with Allylic Acetates by Using a Cellulose–Palladium Catalyst

The reagents were obtained commercially and used without further purification. Cellulose fiber, medium, was obtained from Sigma-Aldrich. 1H NMR and 13C NMR spectra were recorded on a Bruker Avance 300 MHz NMR spectrometer using TMS as the internal standard. Chemical shifts are given in parts per million (δ) and coupling constants (J) in Hz. MS data was obtained on Hewlett Packard HP 5973 quadrupole Mass Selective Detector with interface for 6890 series GC. Thin-layer chromatography (TLC) was performed on silica gel 60 F254 precoated glass plates

Quality risk analysis for sustainable smart water supply using data perception

Constructing Sustainable Smart Water Supply systems are facing serious challenges all around the world with the fast expansion of modern cities. Water quality is influencing our life ubiquitously and prioritizing all the urban management. Traditional urban water quality control mostly focused on routine tests of quality indicators, which include physical, chemical and biological groups. However, the inevitable delay for biological indicators has increased the health risk and leads to accidents such as massive infections in many big cities. In this paper, we first analyse the problem, technical challenges, and research questions. Then we provide a possible solution by building a risk analysis framework for the urban water supply system. It takes indicator data we collected from industrial processes to perceive water quality changes, and further for risk detection. In order to provide explainable results, we propose an Adaptive Frequency Analysis (Adp-FA) method to resolve the data using indicators’ frequency domain information for their inner relationships and individual prediction. We also investigate the scalability properties of this method from indicator, geography and time domains. For the application, we select industrial quality data sets collected from a Norwegian project in 4 different urban water supply systems, as Oslo, Bergen, Strømmen and Aalesund

One-Pot Catalyst-Free Synthesis of β- and γ-Hydroxy Sulfides Using Diaryliodonium Salts and Microwave Irradiation

A simple and rapid one-pot protocol is described for the preparation of α- and β-hydroxy sulfides. The direct solventfree microwave irradiation of diaryliodonium salts, potassium thiocyanate, and ethylene glycol/β-propylene glycol without any catalyst or base affords the final compounds in good yields (65–95%) in around 10–25 min