scholarly journals Recent Advances in Continuous-Flow Reactions Using Metal-Free Homogeneous Catalysts

Catalysts ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1321
Author(s):  
Naoto Sugisawa ◽  
Hiroyuki Nakamura ◽  
Shinichiro Fuse
Keyword(s):  
Continuous Flow ◽  
Low Cost ◽  
Reaction Times ◽  
Toxic Metal ◽  
Homogeneous Catalysts ◽  
Precise Control ◽  
Metal Free ◽  
Acidic Catalysts ◽  
Ready Availability ◽  
Low Toxicity

Developments that result in high-yielding, low-cost, safe, scalable, and less-wasteful processes are the most important goals in synthetic organic chemistry. Continuous-flow reactions have garnered much attention due to many advantages over conventional batch reactions that include precise control of short reaction times and temperatures, low risk in handling dangerous compounds, and ease in scaling up synthesis. Combinations of continuous-flow reactions with homogeneous, metal-free catalysts further enhances advantages that include low-cost and ready availability, low toxicity, higher stability in air and water, and increased synthetic efficiency due to the avoidance of the time-consuming removal of toxic metal traces. This review summarizes recently reported continuous-flow reactions using metal-free homogeneous catalysts and classifies them either as acidic catalysts, basic catalysts, or miscellaneous catalysts. In addition, we compare the results between continuous-flow conditions and conventional batch conditions to reveal the advantages of using flow reactions with metal-free homogeneous catalysts.

scholarly journals Visible Light-Induced Metal Free Surface Initiated Atom Transfer Radical Polymerization of Methyl Methacrylate on SBA-15

2017 ◽  
Author(s):  
Liang Ma ◽  
Na Li ◽  
Jian Zhu ◽  
Xiao Dong Chen
Keyword(s):  
Methyl Methacrylate ◽  
Atom Transfer Radical Polymerization ◽  
Radical Polymerization ◽  
Low Cost ◽  
Polymeric Composite ◽  
Structure Evolution ◽  
Atom Transfer ◽  
Metal Free ◽  
Ready Availability ◽  
Enhanced Adsorption

Surface initiated atom transfer radical polymerization (SI-ATRP) is one of the most versatile technique to modify the surface properties of material. Recent developed metal free SI-ATRP makes such technique more widely applicable. Herein photo-induced metal-free SI-ATRP of methacrylates, such as methyl methacrylate, N-isopropanyl acrylamide, and N,N- dimethylaminoethyl methacrylate, on the surface of SBA-15 was reported to fabricate organic-inorganic hybrid materials. SBA-15 based polymeric composite with adjustable graft ratio was obtained. The structure evolution during the SI-ATRP modification of SBA-15 was monitored and verified by FT-IR, XPS, TGA, BET, and TEM. The obtained polymeric composite showed enhanced adsorption ability for the model compound toluene in aqueous. This procedure provides a low cost, ready availability, and facile modification way to synthesize the polymeric composites without the contamination of metal.

Pleural Effusions: Pathophysiology and Management with Intrapleural Tetracycline

1988 ◽  
Vol 22 (1) ◽  
pp. 15-20 ◽  
Author(s):  
Michael A. Oszko
Keyword(s):  
Side Effects ◽  
Pleural Effusion ◽  
Low Cost ◽  
Pleural Space ◽  
Pleural Effusions ◽  
First Line ◽  
Disease States ◽  
Ready Availability ◽  
Low Toxicity

Chronic or recurrent pleural effusions are a consequence of a variety of disease states and may produce significant pain or discomfort in a patient. Both surgical and pharmacological attempts to control pleural effusions have been tried, with moderate success. This article reviews the pathophysiology of pleural effusion and the role of intrapleural tetracycline in its management. Irritating chemicals, when instilled into the pleural space, are known to produce adhesion of the pleural membranes. Tetracycline has been shown in both animal and human studies to be effective in preventing the recurrence of a pleural effusion while producing only minor side effects, such as fever and pleuritic pain. Studies involving tetracycline in treating pleural effusions are reviewed, and guidelines for the preparation and administration of intrapleural tetracycline are presented. Because of its efficacy, low toxicity, ease of preparation, ready availability, and low cost, tetracycline deserves strong consideration as a first-line agent in the management of recurrent pleural effusions.

Recent advances in cobalt-catalysed C–H functionalizations

2019 ◽  
Vol 17 (48) ◽  
pp. 10119-10141 ◽  
Author(s):  
Alessio Baccalini ◽  
Stefania Vergura ◽  
Pravas Dolui ◽  
Giuseppe Zanoni ◽  
Debabrata Maiti
Keyword(s):  
Noble Metals ◽  
Low Cost ◽  
Recent Advances ◽  
Ready Availability ◽  
Low Toxicity

Ready availability, low cost and low toxicity of cobalt salts have redirected the attention of researchers away from noble metals, such as Pd, Rh, and Ir, towards Co in the field of C–H functionalisation.

scholarly journals Continuous-flow synthesis of primary amines: Metal-free reduction of aliphatic and aromatic nitro derivatives with trichlorosilane

2016 ◽  
Vol 12 ◽  
pp. 2614-2619 ◽  
Author(s):  
Riccardo Porta ◽  
Alessandra Puglisi ◽  
Giacomo Colombo ◽  
Sergio Rossi ◽  
Maurizio Benaglia
Keyword(s):  
Continuous Flow ◽  
Reaction Times ◽  
Nitro Compounds ◽  
Primary Amines ◽  
Flow Conditions ◽  
Metal Free ◽  
Nitro Derivatives ◽  
Aromatic Nitro ◽  
High Yields ◽  
First Time

The metal-free reduction of nitro compounds to amines mediated by trichlorosilane was successfully performed for the first time under continuous-flow conditions. Aromatic as well as aliphatic nitro derivatives were converted to the corresponding primary amines in high yields and very short reaction times with no need for purification. The methodology was also extended to the synthesis of two synthetically relevant intermediates (precursors of baclofen and boscalid).

Nano Phytomedicine Based Delivery System for CNS Disease

2020 ◽  
Vol 21 (9) ◽  
pp. 661-673 ◽  
Author(s):  
Mohammed Asadullah Jahangir ◽  
Chettupalli Anand ◽  
Abdul Muheem ◽  
Sadaf Jamal Gilani ◽  
Mohamad Taleuzzaman ◽  
...  
Keyword(s):  
Herbal Medicine ◽  
Low Cost ◽  
Herbal Medicines ◽  
Herbal Drugs ◽  
Widespread Acceptance ◽  
The Central Nervous System ◽  
Low Toxicity ◽  
Ancient Times ◽  
Plant Sources ◽  
Herbal Formulations

Herbal medicines are being used since ancient times and are an important part of the alternative and traditional medicinal system. In recent decades, scientists are embracing herbal medicines based on the fact that a number of drugs that are currently in use are derived directly or indirectly from plant sources. Moreover, herbal drugs have lesser side effects, albeit are potentially strong therapeutic agents. The herbal medicine market is estimated to be around US $62 billion globally. Herbal medicine has gained widespread acceptance due to its low toxicity, low cost, ease of accessibility and efficacy in treating difficult diseases. Safety and efficacy are another important factors in the commercialization process of herbal medicines. Nanotechnology has been shown to be potentially effective in improving the bioactivity and bioavailability of herbal medicines. Development of nano-phytomedicines (or by reducing the size of phytomedicine), attaching polymers with phytomedicines and modifying the surface properties of herbal drugs, have increased the solubility, permeability and eventually the bioavailability of herbal formulations. Novel formulations such as niosomes, liposomes, nanospheres, phytosomes etc., can be exploited in this area. This article reviews herbal medicines, which have prominent activity in the Central Nervous System (CNS) disorders and reported nano-phytomedicines based delivery systems.

scholarly journals A simple approach to prepare fluorescent molecularly imprinted nanoparticles

RSC Advances ◽  
2021 ◽  
Vol 11 (13) ◽  
pp. 7732-7737
Author(s):  
Fenying Wang ◽  
Dan Wang ◽  
Tingting Wang ◽  
Yu Jin ◽  
Baoping Ling ◽  
...  
Keyword(s):  
High Performance ◽  
Low Cost ◽  
Sol Gel ◽  
Silica Sol ◽  
Simple Approach ◽  
Imprinted Polymer ◽  
Molecularly Imprinted ◽  
Low Toxicity ◽  
Good Biocompatibility ◽  
Molecularly Imprinted Nanoparticles

Fluorescent molecularly imprinted polymer (FMIP) gains great attention in many fields due to their low cost, good biocompatibility and low toxicity. Here, a high-performance FMIP was prepared based on the autocatalytic silica sol–gel reaction.

scholarly journals Converting copper sulfide to copper with surface sulfur for electrocatalytic alkyne semi-hydrogenation with water

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yongmeng Wu ◽  
Cuibo Liu ◽  
Changhong Wang ◽  
Yifu Yu ◽  
Yanmei Shi ◽  
...  
Keyword(s):  
Binding Energy ◽  
Noble Metal ◽  
Atomic Hydrogen ◽  
Copper Sulfide ◽  
Low Cost ◽  
Water Electrolysis ◽  
Metal Free ◽  
Copper Nanowire

AbstractElectrocatalytic alkyne semi-hydrogenation to alkenes with water as the hydrogen source using a low-cost noble-metal-free catalyst is highly desirable but challenging because of their over-hydrogenation to undesired alkanes. Here, we propose that an ideal catalyst should have the appropriate binding energy with active atomic hydrogen (H*) from water electrolysis and a weaker adsorption with an alkene, thus promoting alkyne semi-hydrogenation and avoiding over-hydrogenation. So, surface sulfur-doped and -adsorbed low-coordinated copper nanowire sponges are designedly synthesized via in situ electroreduction of copper sulfide and enable electrocatalytic alkyne semi-hydrogenation with over 99% selectivity using water as the hydrogen source, outperforming a copper counterpart without surface sulfur. Sulfur anion-hydrated cation (S2−-K+(H2O)n) networks between the surface adsorbed S2− and K+ in the KOH electrolyte boost the production of active H* from water electrolysis. And the trace doping of sulfur weakens the alkene adsorption, avoiding over-hydrogenation. Our catalyst also shows wide substrate scopes, up to 99% alkenes selectivity, good reducible groups compatibility, and easily synthesized deuterated alkenes, highlighting the promising potential of this method.

Near-Unity Photoluminescence Quantum Yield and Highly Suppressed Blinking in a Toxic-Metal-Free Quantum Dot

2021 ◽  
Vol 12 (5) ◽  
pp. 1426-1431
Author(s):  
Swarnali Ghosh ◽  
Saptarshi Mandal ◽  
Soumen Mukherjee ◽  
Chayan K. De ◽  
Tridib Samanta ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Quantum Dot ◽  
Toxic Metal ◽  
Metal Free ◽  
Photoluminescence Quantum Yield

scholarly journals Continuous Flow Photochemical and Thermal Multi-Step Synthesis of Bioactive 3-Arylmethylene-2,3-Dihydro-1H-Isoindolin-1-Ones

Molecules ◽  
2019 ◽  
Vol 24 (24) ◽  
pp. 4527 ◽  
Author(s):  
Saira Mumtaz ◽  
Mark J. Robertson ◽  
Michael Oelgemöller
Keyword(s):  
Local Anesthetic ◽  
Continuous Flow ◽  
Reaction Times ◽  
Batch Processes ◽  
Thermal Flow

An effective multi-step continuous flow approach towards N-diaminoalkylated 3-arylmethylene-2,3-dihydro-1H-isoindolin-1-ones, including the local anesthetic compound AL-12, has been realized. Compared to the traditional decoupled batch processes, the combined photochemical–thermal–thermal flow setup rapidly provides the desired target compounds in superior yields and significantly shorter reaction times.

scholarly journals Metal-Free Oxidative Dimerization of Dithiocarbamates: Direct Access to 3,5-Bis-mercapto-1,2,4-thiadiazoles

SynOpen ◽  
2017 ◽  
Vol 01 (01) ◽  
pp. 0138-0142 ◽  
Author(s):  
Azim Halimehjani ◽  
Yazdanbakhsh Nosood ◽  
Shaghayegh Didaran ◽  
Fezzeh Aryanasab
Keyword(s):  
Periodic Acid ◽  
Reaction Times ◽  
Direct Access ◽  
Oxidative Dimerization ◽  
Metal Free

A facile and efficient protocol for the synthesis of 3,5-bis-mercapto-1,2,4-thiadiazoles by the oxidative dimerization of S-alkyl dithiocarbamates using periodic acid as an inexpensive and commercially available oxidant is reported. High to excellent yields and short reaction times are the main advantages of this procedure.

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