Continuous flow (Sulfated) Zirconia Catalysed Cascade Conversion of Levulinic Acid to γ‐Valerolactone

ChemCatChem, Journal Year: 2022, Volume and Issue: 15(3)

Published: Dec. 20, 2022

Abstract γ‐Valerolactone (GVL) is a renewable and versatile platform chemical derived from sustainable carbon feedstocks. The cascade conversion of levulinic acid into GVL requires Brønsted Lewis catalysed reactions. Here, dual‐catalyst bed configuration demonstrated that promotes synergy between sites in sulfated zirconia (SZ) ZrO 2 /SBA‐15 for the liquid phase, continuous flow esterification subsequent catalytic transfer hydrogenation (CTH) to GVL. A saturated surface sulfate monolayer, possessing high density strong sites, was optimal isopropyl levulinate over SZ (>80 % conversion). conformal bilayer, deposited SBA‐15 mesoporous silica mixed Brønsted:Lewis acidity, CTH ester dealcoholisation/cyclisation (>60 selectivity). Maximum stable productivity dual‐bed 2.2 mmol .g cat .h −1 at 150 °C, significantly outperforming either catalyst alone or physical mixture both. Flow chemistry approach achieve spatial control transformations involving distinct catalytically active sites.

Language: Английский

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Recent Advances in the Chemical Synthesis of β-Nicotinamide Mononucleotide

Current Organic Chemistry, Journal Year: 2023, Volume and Issue: 26(24), P. 2151 - 2159

Published: Feb. 2, 2023

Abstract:: β-Nicotinamide mononucleotide (β-NMN), a key precursor in the biosynthesis of nicotinamide adenine dinucleotide (NAD+) mammals, has significant effects replenishing NAD+ levels body, so it obvious ameliorative on metabolic and age-related degenerative diseases. β-NMN is widely used healthcare products, food, cosmetics. It considerable commercial worth promising medical application prospects. Hence, development methods for preparing great research significance. This review summarized analyzed recent developments chemical synthesis from various starting materials, which could provide helpful references investigation new synthetic techniques encourage its further large-scale application.

Language: Английский

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An Eight-Step Continuous-Flow Total Synthesis of Vitamin B1

Engineering, Journal Year: 2023, Volume and Issue: 32, P. 226 - 232

Published: June 8, 2023

Vitamin B1 is widely applied in the healthcare and food industry as an antineuritic antioxidant to maintain normal functioning of nerve conduction, heart, gastrointestinal tract. This study reports on integrated eight-step continuous-flow synthesis vitamin from commercially available 2-cyanoacetamide. The proposed process based advances chemistry, engineering, equipment design, affords improved performance safety compared with batch-mode manufacturing. Several challenges were precisely investigated controlled, including mixing, unexpected clogging, solvent switches, exothermic reaction, prevention side reactions, using various micro-channel flow reactors, mixers, separators, continuous filters. was produced a separated yield 47.7% high purity, total residence time about 3.5 h. protocol enables technology involving up six key principles green chemistry. Hence, application paramount importance for improving security, reducing waste, and, particular, efficiency batch operations that require several days

Language: Английский

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N-Doped graphene fiber anchored Pd nanoparticles as a fixed-bed catalyst for continuous-flow reduction of N-containing unsaturated compounds

Green Synthesis and Catalysis, Journal Year: 2023, Volume and Issue: 5(3), P. 170 - 174

Published: Sept. 9, 2023

Catalytic fixed-bed is an efficient and facile system for scalable organic synthesis due to its continuous fast flow operation process. As a key unit in the system, catalytically active packing materials are required possess some properties, such as high activity, excellent stability, porous structure. Herein, we prepare fibrous catalyst by anchoring Pd nanoparticles on N-doped graphene fiber (NHG) (Pd/NGF). Due loose structure, resultant Pd/NGF can be easily filled into continuous-flow reactor construct with low resistance. The corresponding catalytic exhibits favourable rate (8 mL/min) durability toward reduction reactions of N-containing unsaturated compounds produce aromatic amines. This work provides new design concept catalysts dual-active components (i.e., graphene-derived metal nanoparticles)

Language: Английский

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Huperzine alkaloids: forty years of total syntheses

Natural Product Reports, Journal Year: 2023, Volume and Issue: 41(1), P. 59 - 84

Published: Oct. 11, 2023

Covering: up to 2023Huperzine alkaloids are a group of natural products belonging the

Language: Английский

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