SANS Studies of Polymers in Organic Solvents and Supercritical Fluids in the Poor, Theta, and Good Solvent Domains

Author(s):  
Y. B. Melnichenko ◽  
E. Kiran ◽  
K. Heath ◽  
S. Salaniwal ◽  
H. D. Cochran ◽  
...  
ChemInform ◽  
2005 ◽  
Vol 36 (49) ◽  
Author(s):  
Charles M. Gordon ◽  
Walter Leitner

2006 ◽  
Vol 988 ◽  
Author(s):  
Haifei Zhang ◽  
Irshad Hussain ◽  
James Long ◽  
Bien Tan ◽  
Mathias Brust ◽  
...  

AbstractA “toolkit” of emulsion templating and directional freezing methods has been developed which allows the preparation of a wide variety of organic, inorganic, and metallic materials in a macroporous or hierarchically porous form.1,18,20 The various processes use water, organic solvents, or aqueous/organic emulsions as the template phase. We have shown that the organic solvent can be replaced by liquid CO2 in both the emulsion templating and directional freezing approaches, thus reducing organic waste and offering advantages in applications such as the preparation of biomaterials.


Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 729
Author(s):  
Karol Tutek ◽  
Anna Masek ◽  
Anna Kosmalska ◽  
Stefan Cichosz

This article reviews the use of fluids under supercritical conditions in processes related to the modern and innovative polymer industry. The most important processes using supercritical fluids are: extraction, particle formation, micronization, encapsulation, impregnation, polymerization and foaming. This review article briefly describes and characterizes the individual processes, with a focus on extraction, micronization, particle formation and encapsulation. The methods mentioned focus on modifications in the scope of conducting processes in a more ecological manner and showing higher quality efficiency. Nowadays, due to the growing trend of ecological solutions in the chemical industry, we see more and more advanced technological solutions. Less toxic fluids under supercritical conditions can be used as an ecological alternative to organic solvents widely used in the polymer industry. The use of supercritical conditions to conduct these processes creates new opportunities for obtaining materials and products with specialized applications, in particular in the medical, pharmacological, cosmetic and food industries, based on substances of natural sources. The considerations contained in this article are intended to increase the awareness of the need to change the existing techniques. In particular, the importance of using supercritical fluids in more industrial methods and for the development of already known processes, as well as creating new solutions with their use, should be emphasized.


2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Teresa Rosales-García ◽  
Cristian Jiménez-Martínez ◽  
Anaberta Cardador-Martínez ◽  
Sandra Teresita Martín-del Campo ◽  
Luis A. Galicia-Luna ◽  
...  

Extraction of squalene, a potent natural antioxidant, from puffed A. hypochondriacus seeds was performed by supercritical fluid extraction (SCFE); besides, to have a blank for comparison, extraction was performed also by Soxhlet method using organic solvents (hexane). Chemical proximal composition and seed morphology were determined in raw, puffed, and SCFE-extracted seeds. Extracts were obtained with a 500 mL capacity commercial supercritical extractor and performed between 10 and 30 MPa at 313, 323, and 333 K under constant CO2 flow of 0.18 kg CO2/h during 8 h. The squalene content was determined and the fatty acids present in the extracts were identified by GC-MS. The extract obtained by SCFE from puffed amaranth seeds reached 460 ± 28.1 g/kg squalene in oily extract at 313 K/20 MPa.


2010 ◽  
Vol 4 (1) ◽  
pp. 42-50 ◽  
Author(s):  
Diego T. Santos ◽  
M. Angela A. Meireles

Supercritical fluids have become an attractive alternative due to environmentally friendly solvents. The methods that use supercritical fluids can be conveniently used for various applications such as extraction, reactions, particle formation and encapsulation. For encapsulation purposes, the processing conditions given by supercritical technology have important advantages over other methods that include harsh treatments with regard to pH, temperature, light, the use of organic solvents, etc. Unstable functional pigments such as carotenoids extracted from natural sources have been encapsulated to overcome instability problem. Thus, the most used techniques applicable to this intention are described and discussed in this review as well the recent advances and recent trends in this topic that involves the use of supercritical fluids.


2020 ◽  
Vol 11 (1) ◽  
pp. 319-337 ◽  
Author(s):  
Luis Vázquez ◽  
Celia Bañares ◽  
Carlos F. Torres ◽  
Guillermo Reglero

In recent years, the use of green solvents in enzyme catalysis of lipophilic compounds is achieving increasing interest from different perspectives. Conducting reactions under supercritical fluids, ionic liquids, deep eutectic solvents, and other green solvents affords opportunities to overcome problems associated with the lack of solubility of lipids in conventional solvents and the poor miscibility of substrates. Research on the biocatalytic production of modified lipids in the framework of green chemistry is conducted to improve the efficiency of obtaining the desired products as well as the selectivity, stability, and activity of the enzymatic systems. This overview describes the fundamentals and characteristics of several types of green solvents, the main variables involved in enzymatic processes, and examples and applications in the field of lipid modification.


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