chemical synthesis
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2022 ◽  
Vol 19 ◽  
Author(s):  
Melita Lončarić ◽  
MAJA MOLNAR

Abstract: Recently, more and more researchers are resorting to green methods and techniques to avoid environmental pollution. Accordingly, many researchers have been working on the development of new green synthetic procedures trying to avoid the use of toxic organic solvents. A sustainable concept of green and environmentally friendly solvents in chemical synthesis nowadays encompasses a relatively new generation of solvents called deep eutectic solvents (DESs). DESs often have a dual role in the synthesis, acting as both, solvents and catalysts. In this study, DESs are used in the Knoevenagel synthesis of rhodanine derivatives, with no addition of conventional catalysts. A model reaction of rhodanine and salicylaldehyde was performed in 20 different DESs at 80 °C, in order to find the best solvent, which was further used for the synthesis of the series of desired compounds. A series of rhodanines was synthesized in choline chloride: acetamide (ChCl:acetamide) DES with good to excellent yields (51.4 – 99.7 %).


2022 ◽  
pp. 37-41
Author(s):  
Максим Валерьевич Марченок ◽  
Егор Олегович Рочин ◽  
Марина Всеволодовна Палагина ◽  
Людмила Александровна Текутьева

Проведен анализ информационных источников по существующим технологиям получения витаминов B и B. Кратко описаны преимущества и недостатки известных технологий с использованием различных штаммов-продуцентов, а также технологий с использованием химического синтеза. Предложена принципиальная схема разрабатываемых технологий синтеза данных витаминов, определены наиболее продуктивные штаммы-продуценты и необходимые компоненты питательных сред. Обоснован и представлен перечень продуктов, предназначенных для обогащения витаминами группы В, которые будут получены по разрабатываемым технологиям. The analysis of information sources on existing technologies for obtaining vitamins B and B has been carried out. The advantages and disadvantages of known technologies using various producer strains, as well as technologies using chemical synthesis, are briefly described. A schematic diagram of the developed technologies for the synthesis of these vitamins is proposed, the most productive strains - producers and necessary components of nutrient media are identified. The list of products intended for enrichment with B vitamins, which will be obtained by the developed technologies, has been substantiated and presented.


2022 ◽  
Author(s):  
Alex da Cunha Campos ◽  
Thiago Lopes

Hydrogen Peroxide (H2O2) is a versatile and environmentally friendly chemical oxidant with a remarkably diverse range of applications, including fine chemical synthesis, first aid kits for disinfection, pulp and textile bleaching, wastewater treatment and others. Industrial production of H2O2 is based on the anthraquinone oxidation/reduction process, which consumes a lot of energy, requires complex and large-scale equipment, and mass extraction solvents, generating an enormous waste. There is a general demand for a more decentralised infrastructure, where energy conversion and chemical synthesis are conducted closer to the point of consumption. In this context, developing an electrochemical process to partially reduce O2 to H2O2 (O2 + 2H+/e- → H2O2) in an acidic medium would be an attractive strategy that could be carried out under ambient conditions using renewable energies. However, practical and economic electrocatalysts that exhibit high activity and selectivity for hydrogen peroxide production is to be developed. A series of M-N/C catalysts (M = Fe, Co, and Cu) were prepared in the present study. The performance (activity and selectivity) of these catalysts for the oxygen reduction reaction was investigated in the potential window of 0.2 V to 1.0 V vs. the Reversible Hydrogen Electrode (RHE). Electrochemical measurements demonstrated that the Co-N/C [c] electrocatalyst exhibits high ORR activity and exceptional selectivity for hydrogen peroxide production (92% at 0.5 V vs. RHE).


Author(s):  
Wei-Wei Shi ◽  
Chaowei Shi ◽  
Tong-Yue Wang ◽  
Yu-Lei Li ◽  
Yong-Kang Zhou ◽  
...  
Keyword(s):  

Author(s):  
Tehmina Kousar ◽  
Muhammad Aadil ◽  
Sonia Zulfiqar ◽  
Muhammad Farooq Warsi ◽  
Syeda Rabia Ejaz ◽  
...  

2022 ◽  
pp. 21-53
Author(s):  
Belete Asefa Aragaw ◽  
Melisew Tadele Alula ◽  
Stephen Majoni ◽  
Cecil K. King'ondu

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