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Processes, Volume 3, Issue 4 (December 2015) , Pages 730-778

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Open AccessCommunication Ionic Liquid-Based Aqueous Biphasic Systems—A Facile Approach for Ionic Liquid Regeneration from Crude Plant Extracts
Processes 2015, 3(4), 769-778; https://doi.org/10.3390/pr3040769
Received: 22 August 2015 / Accepted: 21 November 2015 / Published: 26 November 2015
Cited by 6 | Viewed by 2133 | PDF Full-text (579 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
The possibility for simultaneous controlled partition of the biologically active alkaloid S-(+)-glaucine, presented in a crude ionic liquid-aqueous plant extract, and separation of the ionic liquid (IL) employed by means of ionic liquid-based aqueous biphasic systems (IL-ABS) was investigated in this study. [...] Read more.
The possibility for simultaneous controlled partition of the biologically active alkaloid S-(+)-glaucine, presented in a crude ionic liquid-aqueous plant extract, and separation of the ionic liquid (IL) employed by means of ionic liquid-based aqueous biphasic systems (IL-ABS) was investigated in this study. The ABS were formed by the addition of inorganic salts with distinct water-structuring properties such as Na2CO3, MgSO4, (NH4)2SO4, and NaH2PO4 to an enriched of glaucine extract of Glaucium flavum Cr. (Papaveraceae). The influence of the salt type and concentration on the phase-forming ability, as well as the pH value on the partition of glaucine between the two phases formed, was comprehensively studied. It was found that the target alkaloid is predominantly transferred into the IL-rich phase, regardless the influential factors. The results obtained were further used as a platform for the development of an improved extractive procedure, ensuring simultaneous glaucine recovery, IL recycling and water removal in a single technological step. Thus, based on the formation of a three-phase system consisting of butyl acetate, IL-rich phase, and salt-rich phase, nearly quantitative recovery of glaucine (>99%), IL recycling (ca. 90%), and water removal (ca. 85%) were achieved by salt-induced separation of the crude plant extract. Full article
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Open AccessArticle Optimal Design for Reactivity Ratio Estimation: A Comparison of Techniques for AMPS/Acrylamide and AMPS/Acrylic Acid Copolymerizations
Processes 2015, 3(4), 749-768; https://doi.org/10.3390/pr3040749
Received: 15 July 2015 / Accepted: 30 October 2015 / Published: 10 November 2015
Cited by 4 | Viewed by 2691 | PDF Full-text (271 KB) | HTML Full-text | XML Full-text
Abstract
Water-soluble polymers of acrylamide (AAm) and acrylic acid (AAc) have significant potential in enhanced oil recovery, as well as in other specialty applications. To improve the shear strength of the polymer, a third comonomer, 2-acrylamido-2-methylpropane sulfonic acid (AMPS), can be added to the [...] Read more.
Water-soluble polymers of acrylamide (AAm) and acrylic acid (AAc) have significant potential in enhanced oil recovery, as well as in other specialty applications. To improve the shear strength of the polymer, a third comonomer, 2-acrylamido-2-methylpropane sulfonic acid (AMPS), can be added to the pre-polymerization mixture. Copolymerization kinetics of AAm/AAc are well studied, but little is known about the other comonomer pairs (AMPS/AAm and AMPS/AAc). Hence, reactivity ratios for AMPS/AAm and AMPS/AAc copolymerization must be established first. A key aspect in the estimation of reliable reactivity ratios is design of experiments, which minimizes the number of experiments and provides increased information content (resulting in more precise parameter estimates). However, design of experiments is hardly ever used during copolymerization parameter estimation schemes. In the current work, copolymerization experiments for both AMPS/AAm and AMPS/AAc are designed using two optimal techniques (Tidwell-Mortimer and the error-in-variables-model (EVM)). From these optimally designed experiments, accurate reactivity ratio estimates are determined for AMPS/AAm (rAMPS = 0.18, rAAm = 0.85) and AMPS/AAc (rAMPS = 0.19, rAAc = 0.86). Full article
(This article belongs to the Special Issue Polymer Modeling, Control and Monitoring) Printed Edition available
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Open AccessArticle Model-Based Reactor Design in Free-Radical Polymerization with Simultaneous Long-Chain Branching and Scission
Processes 2015, 3(4), 731-748; https://doi.org/10.3390/pr3040731
Received: 29 September 2015 / Accepted: 22 October 2015 / Published: 3 November 2015
Cited by 3 | Viewed by 2586 | PDF Full-text (1976 KB) | HTML Full-text | XML Full-text
Abstract
Polymers are the products of processes and their microstructure can be changed significantly by the reactor systems employed, especially for nonlinear polymers. The Monte Carlo simulation technique, based on the random sampling technique, is used to explore the effect of reactor types on [...] Read more.
Polymers are the products of processes and their microstructure can be changed significantly by the reactor systems employed, especially for nonlinear polymers. The Monte Carlo simulation technique, based on the random sampling technique, is used to explore the effect of reactor types on the branched polymer structure, formed through free-radical polymerization with simultaneous long-chain branching and scission, as in the case of low-density polyethylene synthesis. As a simplified model for a tower-type multi-zone reactor, a series of continuous stirred-tank reactors, consisting of one big tank and the same N-1 small tanks is considered theoretically. By simply changing the tank arrangement, various types of branched polymers, from star-like globular structure to a more randomly branched structure, can be obtained, while keeping the following properties of the final products, the monomer conversion to polymer, the average branching and scission densities, and the relationship between the mean-square radius of gyration and molecular weight. Full article
(This article belongs to the Special Issue Polymer Modeling, Control and Monitoring) Printed Edition available
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Open AccessRetraction Retraction: Review on Valve Stiction. Part I: From Modeling to Smart Diagnosis
Processes 2015, 3(4), 730; https://doi.org/10.3390/pr3040730
Received: 22 September 2015 / Accepted: 22 September 2015 / Published: 25 September 2015
Viewed by 2282 | PDF Full-text (144 KB) | HTML Full-text | XML Full-text
Abstract
We have become aware that a review paper [1] recently published in Processes contained a considerable amount of identical text and a similar structure to a previously published review paper [2], although some novel content was presented, including new citations and a section [...] Read more.
We have become aware that a review paper [1] recently published in Processes contained a considerable amount of identical text and a similar structure to a previously published review paper [2], although some novel content was presented, including new citations and a section on smart diagnosis. [...] Full article
Processes EISSN 2227-9717 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
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