Supercritical Carbon Dioxide: A Glimpse from the Modern Era of Green Chemistry

2020 ◽  
pp. 75-123
Author(s):  
Atul Kumar Varma ◽  
Santanu Ghosh
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Green Chemistry ◽  
Modern Era ◽  
Supercritical Carbon

Free-Radical Chemistry in Supercritical Carbon Dioxide

2004 ◽  
Author(s):  
J. M. Tanko
Keyword(s):  
Carbon Dioxide ◽  
Free Radical ◽  
Supercritical Carbon Dioxide ◽  
Green Chemistry ◽  
Chemical Reactions ◽  
Environmentally Benign ◽  
Supercritical State ◽  
Liquid Phases ◽  
Temperature And Pressure ◽  
Supercritical Carbon

During the 1990s, the chemical industry has focused on ways to reduce and prevent pollution caused by chemical synthesis and manufacturing. The goal of this approach is to modify existing reaction conditions and/or to develop new chemistries that do not require the use of toxic reagents or solvents, or that do not produce toxic by-products. The terms “environmentally benign synthesis and processing” and “green chemistry” have been coined to describe this approach where the environmental impact of a process is as important an issue as reaction yield, efficiency, or cost. Most chemical reactions require the use of a solvent that may serve several functions in a reaction: for example, ensuring homogeneity of the reactants, facilitating heat transfer, extraction of a product (or by-product), or product purification via chromatography. However, because the solvent is only indirectly involved in a reaction (i.e., it is not consumed), its disposal becomes an important issue. Thus, one obvious approach to “green chemistry” is to identify alternative solvents that are nontoxic and/or environmentally benign. Supercritical carbon dioxide (sc CO2) has been identified as a solvent that may be a viable alternative to solvents such as CCl4, benzene, and chloroflurocarbons (CFCs), which are either toxic or damaging to the environment. The critical state is achieved when a substance is taken above its critical temperature and pressure (Tc, Pc). Above this point on a phase diagram, the gas and liquid phases become indistinguishable. The physical properties of the supercritical state (e.g., density, viscosity, solubility parameter, etc.) are intermediate between those of a gas and a liquid, and vary considerably as a function of temperature and pressure. The interest in sc CO2 specifically is related to the fact that CO2 is nontoxic and naturally occurring. The critical parameters of CO2 are moderate (Tc = 31 °C, Pc = 74 bar), which means that the supercritical state can be achieved without a disproportionate expenditure of energy. For these two reasons, there is a great deal of interest in sc CO2 as a solvent for chemical reactions. This chapter reviews the literature pertaining to free-radical reactions in sc CO2 solvent.

scholarly journals Supercritical carbon dioxide: a solvent like no other

2014 ◽  
Vol 10 ◽  
pp. 1878-1895 ◽  
Author(s):  
Jocelyn Peach ◽  
Julian Eastoe
Keyword(s):  
Carbon Dioxide ◽  
Volatile Organic Compounds ◽  
Supercritical Carbon Dioxide ◽  
Green Chemistry ◽  
Physicochemical Properties ◽  
Organic Compounds ◽  
Ionic Species ◽  
Volatile Organic ◽  
Supercritical Carbon

Supercritical carbon dioxide (scCO2) could be one aspect of a significant and necessary movement towards green chemistry, being a potential replacement for volatile organic compounds (VOCs). Unfortunately, carbon dioxide has a notoriously poor solubilising power and is famously difficult to handle. This review examines attempts and breakthroughs in enhancing the physicochemical properties of carbon dioxide, focusing primarily on factors that impact solubility of polar and ionic species and attempts to enhance scCO2 viscosity.

Green Chemistry Using Liquid and Supercritical Carbon Dioxide

2004 ◽  
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Green Chemistry ◽  
Chemical Synthesis ◽  
Industrial Processes ◽  
Environmentally Safe ◽  
Forms Of Carbon ◽  
Supercritical Carbon

Chemists have been researching the potential of liquid and supercritical carbon dioxide for environmentally safe applications. This edited volume will cover the various applications of using these forms of carbon dioxide. The three main areas of focus are catalysis and chemical synthesis in CO2, polymers in CO2, and industrial processes and applications utilizing CO2. The book is aimed at researchers in academia and industry, and the contributors are all experts in the field.

scholarly journals Green Chemistry Extractions of Carotenoids from Daucus carota L.—Supercritical Carbon Dioxide and Enzyme-Assisted Methods

Molecules ◽  
2019 ◽  
Vol 24 (23) ◽  
pp. 4339 ◽  
Author(s):  
Natalia Miękus ◽  
Aamir Iqbal ◽  
Krystian Marszałek ◽  
Czesław Puchalski ◽  
Artur Świergiel
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Green Chemistry ◽  
Daucus Carota ◽  
Antioxidant Properties ◽  
Daucus Carota L ◽  
Assisted Extraction ◽  
Scientific Papers ◽  
Pros And Cons ◽  
Supercritical Carbon

Multiple reviews have been published on various aspects of carotenoid extraction. Nevertheless, none of them focused on the discussion of recent green chemistry extraction protocols, especially for the carotenoids extraction from Daucus carota L. This group of bioactive compounds has been chosen for this review since most of the scientific papers proved their antioxidant properties relevant for inflammation, stress-related disorders, cancer, or neurological and neurodegenerative diseases, such as stroke and Alzheimer’s Disease. Besides, carrots constitute one of the most popular sources of carotenoids. In the presented review emphasis has been placed on the supercritical carbon dioxide and enzyme-assisted extraction techniques for the relevant tetraterpenoids. The detailed descriptions of these methods, as well as practical examples, are provided. In addition, the pros and cons of each method and comparison with the standard solvent extraction have been discussed.

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