The calorimetric investigation of phosphoric acid–N,N-dimethylformamide system

Shmukler, L. E.; Safonova, L. P.; Kinchin, A. N.

doi:10.1016/s0040-6031(03)00140-0

Cited by 8 publications

(7 citation statements)

References 14 publications

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“…Compared with the NMMO cellulose dissolution system of more than 8–10 h at 80–100 °C [9], the dissolution time of the cellulose in the aPPAC solvent is faster, and the dissolution temperature is lower. Within a temperature of 0–5 °C, only 25 minis required for the cellulose to dissolve.…”

Section: Resultsmentioning

confidence: 99%

“…Many processing methods, such as viscose, n -methylmorpholine- n -oxid (NMMO) and ionic liquid process, are available to dissolve and regenerate cellulose. The viscose process, using sodium hydroxide as solvent, leads to acritical environmental pollution problem, whereas the NMMO process [9] is very costly. Ionic liquid is a good solvent for cellulose.…”

Section: Introductionmentioning

confidence: 99%

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Luffa Pretreated by Plasma Oxidation and Acidity to Be Used as Cellulose Films

et al. 2018

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Cellulose is the most abundant natural polymer on earth. With the increasing shortage of oil resources, people have been focusing more on producing natural cellulose. In this study, guaiacol was used as the model compound to investigate the degradation of lignin in luffa. A new cellulose material was extracted from natural luffa by a pretreatment based on the oxidation and acidity of glow discharge plasma in water. The produced luffa cellulose was dissolved in anhydrous phosphoric/polyphosphoric acid (aPPAC) solvent to prepare cellulose film. Results showed that the reactive species of OH·, HO2· and H3O+ were produced during the plasma discharge of water. The free radicals ·OH were useful in eliminating lignin by the destruction of aromatic structure, whereas H3O+ in eliminating hemicellulose in the luffa raw material. At the conditions of luffa powder concentration of 9.26 g/L, discharge time of 20 min, and plasma power of 100W, the cellulose component was increased to 81.2%. After 25 min, the luffa cellulose was completely dissolved in the aPPAC solvent at 0–5 °C. Thus, a regenerated cellulose film of cellulose II was prepared. The aPPAC solvent was a good non-derivatizing solvent for the luffa cellulose. The regenerated film exhibited good mechanical properties, wettability and a compact structure. Therefore, plasma pretreatment was an environmentally friendly and high-efficiency method for luffa degumming. The luffa cellulose can be well used in dissolution and regeneration in films.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Luffa Pretreated by Plasma Oxidation and Acidity to Be Used as Cellulose Films

et al. 2018

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“…The H 3 PO 4 -DMF system has previously been investigated with different physico-chemical methods in order to study the interaction mechanism in the system. The results of the conductivity, 3 viscosimetric, 4 calorimetric 5,6 and FTIR-spectroscopic 7 measurements were reported earlier. These studies give the basis for some conclusions on interactions in the system.…”

Section: Introductionmentioning

confidence: 62%

“…3 The presence of strong intermolecular interactions through hydrogen bonding over the entire concentration range investigated was demonstrated. [4][5][6][7] At low acid concentrations (o0.1 mol fraction (m.f.) H 3 PO 4 ) H 3 PO 4 dimers are probably dissociated, 5,6 while above this concentration dimeric phosphoric acid units predominate and form strong hydrogen bonds to DMF molecules.…”

Section: Introductionmentioning

confidence: 99%

“…[4][5][6][7] At low acid concentrations (o0.1 mol fraction (m.f.) H 3 PO 4 ) H 3 PO 4 dimers are probably dissociated, 5,6 while above this concentration dimeric phosphoric acid units predominate and form strong hydrogen bonds to DMF molecules. The formation of strong hydrogen bonded complexes of H 3 PO 4 and DMF of 2 : 1 composition was supposed to be maximised at 0.67 m.f.…”

Section: Introductionmentioning

confidence: 99%

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Physico-chemical and structural characterization of the binary system phosphoric acid–N,N-dimethylformamide

Fadeeva

Safonova

Persson

2010

Phys. Chem. Chem. Phys.

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The binary phosphoric acid (H(3)PO(4))-N,N-dimethylformamide (DMF) system has very different physico-chemical properties depending on composition. This paper summarizes the physico-chemical data newly collected and reported previously on the H(3)PO(4)-DMF system, and proposes structural models for the different regions of composition. The internal hydrogen bonding between pairs of phosphoric acid molecules in cyclic dimeric units is very important as well as the role of the DMF oxygen as hydrogen bond acceptor linking the dimeric phosphoric acid units into polymeric layers and three-dimensional networks.

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Evaluation of Acid Dissociation Constants in DMSO and DMF by Quantum-Chemical Methods

Krest’yaninov

Safonova

2018

J Solution Chem

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The calorimetric investigation of phosphoric acid–N,N-dimethylformamide system

Cited by 8 publications

References 14 publications

Luffa Pretreated by Plasma Oxidation and Acidity to Be Used as Cellulose Films

Luffa Pretreated by Plasma Oxidation and Acidity to Be Used as Cellulose Films

Physico-chemical and structural characterization of the binary system phosphoric acid–N,N-dimethylformamide

Evaluation of Acid Dissociation Constants in DMSO and DMF by Quantum-Chemical Methods

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