Extractive Separations in Contactors with One and Two Immobilized L/L Interfaces: Applications and Perspectives

Schlosser, Štefan

doi:10.1002/9783527626779.ch23

Cited by 12 publications

(6 citation statements)

References 172 publications

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“…13 Applications of liquid-liquid extraction and pertraction in the recovery and separation processes of organic acids have been recently discussed in papers. [46][47][48] The aim of this work was to measure and model liquid-liquid equilibrium data of 5-methyl-2-pyrazinecarboxylic acid (MPCA) and H 2 SO 4 in systems of (water + organic solvent containing TOA). Some equilibrium data on the extraction of the industrially important MPCA by TOA were published by Kubis ˇova ´et al 49,50 The structure of MPCA is shown in Figure 1.…”

Section: Introductionmentioning

confidence: 99%

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Liquid−Liquid Equilibria of 5-Methyl-2-pyrazinecarboxylic and Sulfuric Acids for Solvents with Trioctylamine

2010

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Liquid-liquid equilibrium data of 5-methyl-2-pyrazinecarboxylic acid (MPCA) and H 2 SO 4 in water + organic solvent systems with the reactive extractant trioctylamine (TOA) are presented together with the model of equilibrium. Dissociation constants of both acids were also determined. The addition of 1 kmol • m -3 of Na 2 SO 4 decreased the pK a of MPCA and pK a2 of H 2 SO 4 from 3.09 to 2.87 and from 2.10 to 0.908, respectively. In the extraction of MPCA, the overloading of TOA indicated the formation of (p, 1) complexes (HMPCA) p TOA with p ) 1 to 3. The (1, 1) complex is more stable in n-alkanes with isodecanol. Other (p, 1) complexes are more stable in xylene. H 2 SO 4 with TOA in xylene form (r, q) complexes, (SO 4 2-) q-r (HSO 4 -) 2r-q (HTOA + ) q . At low H 2 SO 4 concentrations, a (1, 2) complex, TOA/sulfate, is formed. On increasing the acid concentration, the expected (1, 1) complex, TOA/hydrogen sulfate, aggregates, probably immediately, to complexes (2, 3) and (3, 3). When the ionic strength was increased by Na 2 SO 4 , the extraction of H 2 SO 4 was less effective. High water content of the solvent loaded with H 2 SO 4 with the stoichiometry (1, 2) suggests the formation of reverse micelles similarly as observed in ionic liquids.

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Section: Introductionmentioning

confidence: 99%

“…Applications of liquid−liquid extraction and pertraction in the recovery and separation processes of organic acids have been recently discussed in papers. − …”

Section: Introductionmentioning

confidence: 99%

Liquid−Liquid Equilibria of 5-Methyl-2-pyrazinecarboxylic and Sulfuric Acids for Solvents with Trioctylamine

2010

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“…Regular teachers appear to be more upset by, or less tolerant of, the problem behaviors of students than are special education teachers (Algozzine, 1980;Yard & Thurman, 1980), and the types of problem behaviors reported to upset teachers the most are "socially defiant" behaviors (Algozzine, 1977). Further, behaviors characteristic of boys are more bothersome to teachers than behaviors characteristic of girls (Schlosser & Algozzine, 1979). Teachers have been shown to rate behaviors of emotionally disturbed students as more disturbing than behaviors of learning disabled students (Mooney & Algozzine, 1978).…”

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confidence: 99%

Teacher ratings of problem behaviors: Which student behaviors “concern” and “disturb” teachers?

Hutton

1984

Psychol. Schs.

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Fifty elementary techers rated the problem behaviors of students to indicate both how much the behaviors "disturbed" them and how much they were "concerned" about the behaviors. The results suggest that teachers are more concerned about behaviors than disturbed by them. However, teachers were both disturbed and concerned about aggressive interaction with and between students. The implications of the findings are discussed.Respect for the ecological model (Hobbs, 1978) calls for techniques to assess interactions between teachers and students when it is suspected that a student may be emotionally disturbed or disturbing. Behavior rating scales often are used in this regard, since information supplied by teachers on rating scales is likely to index not only the student's behavior in the classroom, but also the perception of the teacher. Within the ecological framework, the scores on behavior rating scales reveal information about the rater as well as the student and the system within which the interaction is occurring.Those who have studied the "disturbingness" of problem behaviors have documented that students may disturb teachers by exhibiting certain behaviors. Regular teachers appear to be more upset by, or less tolerant of, the problem behaviors of students than are special education teachers (Algozzine, 1980;Yard & Thurman, 1980), and the types of problem behaviors reported to upset teachers the most are "socially defiant" behaviors (Algozzine, 1977). Further, behaviors characteristic of boys are more bothersome to teachers than behaviors characteristic of girls (Schlosser & Algozzine, 1979). Teachers have been shown to rate behaviors of emotionally disturbed students as more disturbing than behaviors of learning disabled students (Mooney & Algozzine, 1978).Studies of the "disturbingness" of problem behaviors report results that suggest that teachers may give ratings to students to reflect the degree of disturbance they feel about the students. If this is the case, the ratings may assist in identifying not only the student who may need intervention, but also the teacher and the setting that requires more attention. Perhaps scores on behavior rating scales reflect more than the degree of disturbance a teacher feels about a student. Teachers may be "concerned" about a student but not be "disturbed" by the student's behavior. Rating scales that imply that a teacher should rate behaviors that "concern" the teacher may yield different results than those that imply that ratings should reflect how much a behavior upsets or bothers a teacher.The purpose of the present study was to compare ratings of behaviors under two conditions. It was expected that teachers would vary their ratings according to whether they were rating behaviors that "concern" them or behaviors that "disturb" them. It was also expected that teachers would be more "concerned" about and "disturbed" by some behaviors than by others.Reprint requests should be sent to Jerry 8.

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“…The proposed model based on the mass action law for simultaneous extraction of MPCA and H 2 SO 4 by TOA assuming both binary and ternary complexes fitted the data very well. The modeling resulted in a set of equilibrium reaction constants of two binary (MPCA + TOA) complexes, (1, 0, 1) and (2, 0, 1) and five ternary (MPCA + H 2 SO 4 + TOA) complexes (1, 1, 2), (2, 1, 2), (3, 1, 2), (1, 2, 3), and (3,2,3). All ternary complexes can be regarded as formerly (H 2 SO 4 + TOA) complexes (0, 1, 2) and (0, 2, 3) where H 2 SO 4 is joined with TOA in the form of ion pairs and molecules of MPCA are joined with H 2 SO 4 by hydrogen bonding.…”

Section: Discussionmentioning

confidence: 99%

“…In Figures 6 to 9 the area between two curves always belongs to the contribution of one complex and the vertical distances between curves are the contributions of the individual complexes at the given concentration of MPCA, c aF,MPCA . These contributions are always ordered from bottom to top as follows: first are (p, 0, 1) complexes (1, 0, 1) and (2, 0, 1), then (0, r, q) complexes (0, 1, 2), (0, 2, 3) and (0, 3, 3) (only z E , i.e., Figures 8 and 9b), then (p, 1, 2) complexes (1, 1, 2), (2, 1, 2) and (3, 1, 2) and finally (p, 2, 3) complexes (1, 2, 3), (2,2,3). The borders between the sets of (p, 0, 1), (0, r, q) and (p, r, q) complexes are boldfaced.…”

Section: Model Of Liquid-liquid Equilibriummentioning

confidence: 93%

Liquid−Liquid Equilibria of 5-Methyl-2-Pyrazinecarboxylic Acid in Systems (Aqueous Solution with Increased Ionic Strength) + (Solvent with Trioctylamine)

2010

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Liquid−liquid equilibrium data of 5-methyl-2-pyrazinecarboxylic acid (MPCA) in two-phase systems with acidic aqueous solution containing Na2SO4 and/or NaCl and organic solvent (trioctylamine (TOA) + xylene) are presented. Data from systems containing Na2SO4 were successfully correlated using an equilibrium model. Modeling of systems with chlorides needs more data. MPCA and inorganic acids are extracted simultaneously via two mechanisms. The first is competitive extraction of MPCA and inorganic acids for free TOA. This results in the formation of binary (MPCA + TOA) and (inorganic acid + TOA) complexes. The second mechanism is coextraction of acids resulting in ternary complexes (MPCA + inorganic acid + TOA). Competitive extraction dominates in the presence of NaCl. This suppressed the extraction of MPCA because its affinity to TOA is much lower compared to HCl. Coextraction dominates in the presence of Na2SO4. In this case, extraction of MPCA is comparable or even better than in systems without inorganic species. A solvent with (H2SO4 + TOA) complexes which are de facto ionic liquids provides better extraction of MPCA from aqueous solutions.

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Extractive Separations in Contactors with One and Two Immobilized L/L Interfaces: Applications and Perspectives

Cited by 12 publications

References 172 publications

Liquid−Liquid Equilibria of 5-Methyl-2-pyrazinecarboxylic and Sulfuric Acids for Solvents with Trioctylamine

Liquid−Liquid Equilibria of 5-Methyl-2-pyrazinecarboxylic and Sulfuric Acids for Solvents with Trioctylamine

Teacher ratings of problem behaviors: Which student behaviors “concern” and “disturb” teachers?

Liquid−Liquid Equilibria of 5-Methyl-2-Pyrazinecarboxylic Acid in Systems (Aqueous Solution with Increased Ionic Strength) + (Solvent with Trioctylamine)

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