University of Avignon

About: University of Avignon is a education organization based out in Avignon, Provence-Alpes-Côte-d'Azur, France. It is known for research contribution in the topics: Population & Speaker recognition. The organization has 1526 authors who have published 3766 publications receiving 88928 citations.

Green Extraction: From Concepts to Research, Education, and Economical Opportunities

Abstract: One of the principal aims of sustainable development of green processing is in the teaching of green chemistry in colleges, high schools, and academic laboratories of both developed and developing nations. The researchers from academia and professionals from industry have chosen not to ignore the potential consequences of green chemistry and processes and have realized that they have responsibilities in education, research, and acceptance for industrial implementation of green chemistry (analysis, extraction, synthesis, separation, etc.) [1].They recognize that their research will affect the future of the planet with the creation of new products and processes that improve the quality of life and reduce environmental hazards [2–4]. The implementation of green chemistry technologies minimizes the use of materials that are hazardous to human health and environment [5], decreases energy and water usage, and maximizes efficiency (Figure 1.1). Extraction of natural products has been used probably since the discovery of fire. Egyptians and Phoenicians, Jews and Arabs, Indians and Chinese, Greeks and Romans, and even theMayans andAztecs, all possessed innovative extraction processes (maceration, alembic distillation, etc.) used even for perfume, medicine, or food. However, during the 1990s, it was not easy to find literature concerning the dispersed efforts for greening the extraction practices. It was necessary to wait for the tremendous development of green chemistry made by the Environmental Protection Agency (EPA) and led by Paul Anastas [3], who published a series of fundamental books from 1994 trying to create a general conscience on the need for green chemistry. Recent trends in extraction techniques have largely focused on finding solutions that minimize the use of solvent and energy, such as supercritical fluid extraction, ultrasound extraction, subcritical water extraction, controlled pressure drop process, pulse electric field, and microwave extraction. The tremendous efforts made in greening extraction processes can be evaluated through the consideration of books devoted to these aspects as can be seen in Figure 1.2.Theoretical and

Reactivity of Superoxide Radical Anion and Hydroperoxyl Radical with α-Phenyl-N-tert-butylnitrone (PBN) Derivatives

Abstract: Nitrones have exhibited pharmacological activity against radical-mediated pathophysiological conditions and as analytical reagents for the identification of transient radical species by electron paramagnetic resonance (EPR) spectroscopy. In this work, competitive spin trapping, stopped-flow kinetics, and density functional theory (DFT) were employed to assess and predict the reactivity of O2•− and HO2• with various para-substituted α-phenyl-N-tert-butylnitrone (PBN) spin traps. Rate constants of O2•− trapping by nitrones were determined using competitive UV−vis stopped-flow method with phenol red (PR) as probe, while HO2• trapping rate constants were calculated using competition kinetics with 5,5-dimethylpyrroline N-oxide (DMPO) by employing EPR spectroscopy. The effects of the para substitution on the charge density of the nitronyl-carbon and on the free energies of nitrone reactivity with O2•− and HO2• were computationally rationalized at the PCM/B3LYP/6-31+G(d,p)//B3LYP/6-31G(d) level of theory. Theore...