scholarly journals Application of an enzymatic cascade reaction for the synthesis of the emeraldine salt form of polyaniline

2021 ◽  
Author(s):  
Minoru Kurisu ◽  
Reinhard Kissner ◽  
Masayuki Imai ◽  
Peter Walde
Keyword(s):  
Cascade Reaction ◽  
Emeraldine Salt ◽  
Salt Form ◽  
Experimental Conditions ◽  
Peroxidase Isoenzyme ◽  
Large Unilamellar Vesicles ◽  
Dark Green ◽  
Catalyzed Oxidation ◽  
Reference Reaction

AbstractThe synthesis of the emeraldine salt form of polyaniline (PANI-ES) from aniline with Aspergillus sp. glucose oxidase (GOD), d-glucose, dissolved O2, and horseradish peroxidase isoenzyme C (HRPC) in the presence of large unilamellar vesicles of AOT (sodium bis-(2-ethylhexyl)sulfosuccinate) as templates at pH = 4.3 and T ~ 25 °C was investigated in a systematic way. In this cascade reaction mixture, the oxidation of aniline is catalyzed by HRPC with H2O2 that is formed in situ as byproduct of the GOD-catalyzed oxidation of d-glucose with O2. Under the elaborated experimental conditions which we considered ideal, the formation of PANI-ES products is evident, as judged by UV/Vis/NIR and EPR measurements. Comparison was made with a reference reaction, which was run under similar conditions with added H2O2 instead of GOD and d-glucose. Although the reference reaction was found to be superior, with the cascade reaction, PANI-ES products can still be obtained with high aniline conversion (> 90%) within 24 h as stable dark green PANI-ES/AOT vesicle dispersion. Our results show that the in situ formation of H2O2 does not prevent the inactivation of HRPC known to occur in the reference reaction. Moreover, the GOD used in the cascade reaction is inactivated as well by polymerization intermediates.

scholarly journals The Use of Le Bail Method to Analyze the Semicrystalline Pattern of a Nanocomposite Based on Polyaniline Emeraldine-Salt Form andα-Al2O3

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Edgar A. Sanches ◽  
Adriano de S. Carolino ◽  
Amanda L. dos Santos ◽  
Edson G. R. Fernandes ◽  
Daniela M. Trichês ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Room Temperature ◽  
Structural Characteristics ◽  
Pure Pani ◽  
Emeraldine Salt ◽  
Salt Form ◽  
Absorption Bands ◽  
Physical Deposition ◽  
Average Size

Ceramic nanocomposites constituted by a matrix ofα-Al2O3microparticles reinforced by polyaniline emeraldine-salt form (PANI-ES) nanoparticles were prepared byin situpolymerization and characterized structural and morphologically. Peaks related to both materials were observed through XRD technique: PANI-ES presented peaks at2θ= 8.9, 14.9, 20.8, 25.3, 27.1, and 30.0° and inα-Al2O3phase peaks were found at2θ= 25.6, 35.2, 37.9, 43.5, 52.6, 57.6, and 68.1°. Nanocomposite crystallinity percentage was estimated around 70%. SEM showed a polymerization of PANI-ES over alumina plates. By Le Bail method it was observed that PANI-ES andα-Al2O3have crystallite average size around, respectively, 41 and 250 Å. By FTIR analysis characteristic absorption bands of both materials were identified. Additional bands indicating new chemical bonds were not observed, suggesting that nanocomposite was formed by physical deposition. Nanocomposite DC electrical conductivity was found around 0.24 S/cm (against1.84×10-4 S/cm for pure PANI-ES), showing an increase of about 1,300 times compared to the pure PANI-ES at room temperature. Thus, this paper showed that both materials have kept its original structural characteristics and exhibited high electrical conductivity when combined in nanocomposite form.

scholarly journals Effect of template type on the preparation of the emeraldine salt form of polyaniline (PANI-ES) with horseradish peroxidase isoenzyme C (HRPC) and hydrogen peroxide

RSC Advances ◽  
2019 ◽  
Vol 9 (57) ◽  
pp. 33080-33095 ◽  
Author(s):  
Tomoyuki Fujisaki ◽  
Keita Kashima ◽  
Sandra Serrano-Luginbühl ◽  
Reinhard Kissner ◽  
Danica Bajuk-Bogdanović ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Horseradish Peroxidase ◽  
Emeraldine Salt ◽  
Salt Form ◽  
Peroxidase Isoenzyme ◽  
Different Types

Different types of templates consisting of sulfonate or sulfate groups were compared for the horseradish peroxidase/H2O2-catalysed synthesis of the emeraldine salt form of polyaniline from aniline at pH = 4.3.

In situ monitoring of isophorone diisocyanate-based flexible polyurethane foams formation

2016 ◽  
Vol 54 (1) ◽  
pp. 37-52 ◽  
Author(s):  
I Eceiza ◽  
L Irusta ◽  
A Barrio ◽  
MJ Fernández-Berridi
Keyword(s):  
Foam Height ◽  
Polyurethane Foams ◽  
In Situ Monitoring ◽  
Generation Process ◽  
Isophorone Diisocyanate ◽  
Experimental Conditions ◽  
Foaming Process ◽  
Foam Generation ◽  
Flexible Polyurethane

Novel isophorone diisocyanate-based flexible polyurethane foams were prepared by the one-step method in a computerized foam qualification system (FOAMAT). The experimental conditions to obtain this type of foams, in relation to the nature and concentration of catalysts as well as the reaction temperature, were established as no data were available in scientific literature. The chemical reactions occurring during the foam generation process were monitored in situ by attenuated total reflectance-FTIR spectroscopy. The kinetics of the foam generation was fitted to an nth order model and the data showed that the foaming process adjusted to a first-order kinetics. The physical changes as pressure, foam height, and dielectric polarization were monitored by the FOAM software (FOAMAT). According to these parameters, the foaming process was divided into four steps: bubble growth, bubble packing, cell opening, and final curing.

The Effect of Lesion Characteristic on Remineralization and Model Sensitivity

1992 ◽  
Vol 71 (3_suppl) ◽  
pp. 811-813 ◽  
Author(s):  
F. Schäfer ◽  
S.J. Raven ◽  
T.A. Parr
Keyword(s):  
Real Life ◽  
High Sensitivity ◽  
Lesion Size ◽  
Experimental Conditions ◽  
Treatment Groups ◽  
Human Enamel ◽  
Enamel Sample ◽  
Two Factors ◽  
Treatment Bias

A major criterion for assessing the value of any experimental model in scientific research is the degree of correspondence between its results and data from the real-life process it is designed to model. Intra-oral models aimed at predicting the anti-caries efficacy of toothpastes or other topical treatments should therefore be calibrated against treatments proven to be effective in a caries clinical trial. For this to be achieved, it is necessary that a model with high sensitivity be designed, while at the same time retaining relevance to the process to be modeled. This means that the effects of the various experimental conditions and parameters of the model on its performance must be understood. The purpose of this paper was to assess the influence of two specific factors on the performance of an in situ enamel remineralization model, which is based on human enamel slabs attached to partial dentures. The two factors are initial lesion severity and origin of enamel sample. The results indicated that initial lesion size affected whether net remineralization or net demineralization occurred during in situ treatment. Samples with an initial range of from 1500 to 2500 (ΔZ) tended more toward demineralization than did samples with ΔZ > 3500. This means that treatment groups must be well-balanced with respect to initial lesion size. Differences in initial demineralization severity between different tooth locations must also be considered so that systematic treatment bias can be avoided. The solution used in the model discussed here is based on a balanced experimental design, which allows this effect to be taken into account in the data analysis.

scholarly journals Reproduction of vesicles coupled with a vesicle surface-confined enzymatic polymerisation

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Minoru Kurisu ◽  
Harutaka Aoki ◽  
Takehiro Jimbo ◽  
Yuka Sakuma ◽  
Masayuki Imai ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Horseradish Peroxidase ◽  
External Solution ◽  
Molecular Assembly ◽  
Darwinian Evolution ◽  
Assembly Systems ◽  
Emeraldine Salt ◽  
Minimal Cell ◽  
Salt Form ◽  
Reproduction System

Abstract Molecular assembly systems that have autonomous reproduction and Darwinian evolution abilities can be considered as minimal cell-like systems. Here we demonstrate the reproduction of cell-sized vesicles composed of AOT, i.e., sodium bis-(2-ethylhexyl) sulfosuccinate, coupled with an enzymatic polymerisation reaction occurring on the surface of the vesicles. The particular reaction used is the horseradish peroxidase-catalysed polymerisation of aniline with hydrogen peroxide as oxidant, which yields polyaniline in its emeraldine salt form (PANI-ES). If AOT micelles are added during this polymerisation reaction, the AOT - PANI-ES vesicles interact with the AOT molecules in the external solution and selectively incorporate them in their membrane, which leads to a growth of the vesicles. If the AOT vesicles also contain cholesterol, the vesicles not only show growth, but also reproduction. An important characteristic of this reproduction system is that the AOT-based vesicles encourage the synthesis of PANI-ES and PANI-ES promotes the growth of AOT vesicles.

Industrial passion fruit residue as ruminant feed

1998 ◽  
Vol 1998 ◽  
pp. 173-173
Author(s):  
C.M. Korndörfer ◽  
A. L. Abdalla ◽  
E. Crossara
Keyword(s):  
Nutritive Value ◽  
Ammonia Nitrogen ◽  
Neutral Detergent Fiber ◽  
Passion Fruit ◽  
Experimental Conditions ◽  
Plastic Bags ◽  
Treatment Structure ◽  
Good Medium ◽  
Male Sheep

In the Brazilian savanna region, which covers 2.1 million km2, roughage production is irregular during the year. However the manufacture of passion fruit juice produces approximately 13,000,000 ton per year of industrial residue which consist of fruit pulp and seeds (FPSR) (Medina, 1980). Beef and dairy cattle farmers are feeding it to their livestock with no knowledge of its nutritive value or concern for its pollution aspects. The FPSR is left in piles outside on the ranches and fluid effluent is often observed reaching streams and contaminating the environment. Furthermore it is a good medium for fly proliferation which stresses the animals and reduces profits. The objective of this study was to demonstrate to the farmers a better way for storing the FPSR and to determine its nutritional value for ruminants.The FPSR was stored in triplicate experimental mino-silos (200 1) in a complete 2x2 factorial design to observe the effects of 48-h wilting (sun dry) and anaerobic conditions. Open mini-silos were left uncovered while in anaerobic mini-silos the FPSR was sealed in plastic bags and covered with sacks of soil. Treatments were: Tl wilted and anaerobic; T2 wilted and open; T3 unwilted and anaerobic; T4 unwilted and open. The mini-silos were sampled at 30-day intervals for up to ll2 days. The samples were analysed for dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), lignin (LIN), phenolic compounds (PHEN), ammonia nitrogen (NH3 -N), soluble carbohydrats (CHO sol) and pH. The DM effective degradability (DMED) was determined “in situ” using six Santa Inês male sheep fitted with rumen cannula and fed with a mixture 80:20 diet containing grass pasture and concentrate (160 g CP/kg DM). The effects of experimental conditions were analysed in a factorial treatment structure and tested by analysis of variance. Treatment means were compared by contrasts.

Electrical properties and conduction mechanism of in situ HCl-doped emeraldine salt polyaniline films deposited on n-ZnS/p-Si(100)

2018 ◽  
Vol 5 (7) ◽  
pp. 15180-15185
Author(s):  
Kathrina P. Gumahad ◽  
Reynaldo M. Vequizo ◽  
Majvell Kay G. Odarve-Vequizo ◽  
Bianca Rae B. Sambo-Fabricante
Keyword(s):  
Electrical Properties ◽  
Conduction Mechanism ◽  
Emeraldine Salt ◽  
Polyaniline Films

A Copper Halide Promoted Regioselective Halogenation of Coumarins Using N-Halosuccinimide as Halide Source

Synlett ◽  
2019 ◽  
Vol 30 (05) ◽  
pp. 630-634 ◽  
Author(s):  
Min Zhang ◽  
Jinling Su ◽  
Yan Zhang ◽  
Mingren Chen ◽  
Weiming Li ◽  
...  
Keyword(s):  
Metal Halide ◽  
Regioselective Synthesis ◽  
Electrophilic Aromatic Substitution ◽  
Aromatic Substitution ◽  
Copper Halide ◽  
Experimental Conditions ◽  
Heteroaromatic Compounds ◽  
Convenient Approach ◽  
In Situ Generation

A safe, convenient, and regioselective synthesis of 3-halo coumarins using a metal halide (CuX2 alone or with ZnX2) promoted halogenation with N-halosuccinimide (NXS) as halide source is reported. The synthesis involved the steady in situ generation of highly reactive positive halogen (X+) by the coordination of copper or zinc with the N-halosuccinimide and subsequent electrophilic aromatic substitution of the electron-deficient coumarins. This procedure works well also for the halogenation of less electron-rich naphthoquinones, flavones, and methoxypsoralen in moderate to quantitative yields. This protocol features simple experimental conditions using readily available inexpensive reagents and provides a convenient approach to the chlorination or bromination of some useful heteroaromatic compounds.

Visible-Light Photoredox-Catalyzed Cascade Reaction for the Synthesis of Pyrrolo[2,1-a]isoquinoline-Substituted Phosphonates

Synthesis ◽  
2018 ◽  
Vol 51 (02) ◽  
pp. 522-529 ◽  
Author(s):  
Deqing Shi ◽  
Lingna Wang ◽  
Tiancong Ma ◽  
Mingming Qiao ◽  
Qiangxian Wu ◽  
...  
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Room Temperature ◽  
Cascade Reaction ◽  
Efficient Synthesis ◽  
Reaction Conditions ◽  
One Pot ◽  
Oxidative Aromatization ◽  
Activated Olefins ◽  
Catalyzed Oxidation

A visible-light photoredox-catalyzed oxidation/[3+2] cycloaddition/oxidative aromatization cascade reaction of [(3,4-dihydroisoquinolin-2(1H)-yl)methyl]phosphonates and activated olefins or alkynes for the efficient synthesis of potentially biological active pyrrolo[2,1-a]isoquinoline-substituted phosphonates was developed. This transformation features mild reaction conditions (i.e., visible light irradiation, room temperature), molecular oxygen (O2) as a green oxidant, simple ‘one-pot’ operation.

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