scholarly journals Synthesis of Poly(Trimethylene Carbonate) from Amine Group Initiation: Role of Urethane Bonds in the Crystallinity

Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 280
Author(s):  
Thomas Brossier ◽  
Gael Volpi ◽  
Vincent Lapinte ◽  
Sebastien Blanquer
Keyword(s):  
Thermal Studies ◽  
Trimethylene Carbonate ◽  
X Ray Diffraction ◽  
One Pot ◽  
Free Process ◽  
One Step ◽  
The One ◽  
Natural Amino Acids ◽  
The Impact

Semi-crystalline poly(trimethylene carbonate) (PTMC) can be efficiently prepared by ring-opening polymerization (ROP) initiated by amine using various catalysts. More promising results were reached with the one-step process of stannous octanoate unlike the two-step one-pot reaction using TBD and MSA catalysts. The ROP-amine of TMC consists in a simple isocyanate free process to produce polycarbonate-urethanes, compatible with the large availability of amines ranging from mono- to multifunctional until natural amino acids. ROP-amine of TMC leads to urethane bonds monitored by FTIR spectroscopy. The relationship between the nature of amines and the crystallinity of PTMC was discussed through X-ray diffraction and thermal studies by DSC and TGA. The impact of the crystallinity was also demonstrated on the mechanical properties of semi-crystalline PTMC in comparison to amorphous PTMC, synthesized by ROP initiated by alcohol. The semi-crystalline PTMC synthesized by ROP-amine opens many perspectives.

scholarly journals Trifluoroacetic Acid Hydroxylamine System as Organocatalyst Reagent in a One-Pot Salt Free Process for the Synthesis of Caprolactam and Amides of Industrial Interest

2021 ◽  
Author(s):  
F. Manente ◽  
L. Pietrobon ◽  
L. Ronchin ◽  
A. Vavasori
Keyword(s):  
Trifluoroacetic Acid ◽  
Room Temperature ◽  
Beckmann Rearrangement ◽  
One Pot ◽  
Free Process ◽  
Hydrogenation Reactions ◽  
One Step ◽  
The One ◽  
Industrial Relevance

AbstractIn this work we studied the reactivity of the Trifluoroacetic acid hydroxylamine system in the one step salt free synthesis of amides from ketones. A particular regards was paid to the caprolactam synthesis because of its industrial relevance. Synthesis, reactivity and characterization of the hydroxylamine trifluoroacetate is given. Fast oximation reaction of several ketones was gained at room temperature (1 h of reaction quantitative conversion for several ketones). In the same reactor, by raising the temperature at 383 K, the Beckmann rearrangement of the so obtained oximes is easily accomplished in the presence of three equivalent of TFA. The possibility of obtaining the trifluoroacetate of the hydroxylamine with a modified nitric acid hydrogenation reactions was verified, too. Reuse of solvent and trifluoroacetic acid is easily achieved by distillation. Graphical abstract Salt free one-pot caprolactam and amides process catalyzed by CF3COOH, in the presence of NH2OH TFA as the oximation agent.

A Study on the Rearrangement of Dialkyl 1-Aryl-1-hydroxymethylphosphonates to Benzyl Phosphates

2020 ◽  
Vol 24 (4) ◽  
pp. 465-471 ◽  
Author(s):  
Zita Rádai ◽  
Réka Szabó ◽  
Áron Szigetvári ◽  
Nóra Zsuzsa Kiss ◽  
Zoltán Mucsi ◽  
...  
Keyword(s):  
Quantum Chemical ◽  
Room Temperature ◽  
Phase Transfer ◽  
One Pot ◽  
Substrate Dependence ◽  
Triethylbenzylammonium Chloride ◽  
One Step ◽  
The Pudovik Reaction ◽  
The One ◽  
Solid Liquid

The phospha-Brook rearrangement of dialkyl 1-aryl-1-hydroxymethylphosphonates (HPs) to the corresponding benzyl phosphates (BPs) has been elaborated under solid-liquid phase transfer catalytic conditions. The best procedure involved the use of triethylbenzylammonium chloride as the catalyst and Cs2CO3 as the base in acetonitrile as the solvent at room temperature. The substrate dependence of the rearrangement has been studied, and the mechanism of the transformation under discussion was explored by quantum chemical calculations. The key intermediate is an oxaphosphirane. The one-pot version starting with the Pudovik reaction has also been developed. The conditions of this tandem transformation were the same, as those for the one-step HP→BP conversion.

The Role of Cuprous Oxide Seeds in the One-Pot and Seeded Syntheses of Copper Nanowires

Small ◽  
2014 ◽  
Vol 10 (9) ◽  
pp. 1771-1778 ◽  
Author(s):  
Shengrong Ye ◽  
Aaron R. Rathmell ◽  
Yoon-Cheol Ha ◽  
Adria R. Wilson ◽  
Benjamin J. Wiley
Keyword(s):  
Cuprous Oxide ◽  
Copper Nanowires ◽  
One Pot ◽  
The One

scholarly journals One-Pot Synthesis of Ru-Doped ZnO Oxides for Photodegradation of 4-Chlorophenol

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Maria E. Manríquez ◽  
Luis Enrique Noreña ◽  
Jin An Wang ◽  
Lifang Chen ◽  
Jose Salmones ◽  
...  
Keyword(s):  
Band Gap ◽  
Mixed Oxides ◽  
Active Surface ◽  
Band Gap Energy ◽  
X Ray Diffraction ◽  
Electron Hole ◽  
One Pot ◽  
Notable Increase ◽  
Doped Zno ◽  
The One

The photocatalytic degradation of 4-chlorophenol in water using Ru-doped ZnO mixed oxides (0, 0.5, 1, and 3 wt% RuO2) synthesized by the one-pot homogeneous coprecipitation method is reported. ZnO with wurtzite structure was present in the mixed oxide as corroborated by Raman spectroscopy and X-ray diffraction analysis. All the samples showed nanorod morphological features. The presence of Ru6+/Ru4+ couples on ZnO modified the band gap of the mixed oxides and led to a shift of the band gap energy from 3.20 eV to 3.07 eV. Ru addition increased the surface area and significantly promoted the formation of active surface oxygen species such as hydroradicals evidenced by the fluorescence spectroscopy measurement. In the photodegradation of 4-chlorophenol solution under UV irradiation, a notable increase in photoactivity was obtained as the amount of RuO2 in the mixed oxides increased to 3 wt%. The charge transfer between Ru6+/Ru4+ couples and ZnO nanoparticles together with the formation of free radical oxidant species effectively inhibits electron-hole recombination rate, thus favoring the photodegradation of 4-chlorophenol.

scholarly journals How Will the Use of Technology in Translation and Testing Affect Language Learning?

2014 ◽  
Vol 8 (1) ◽  
pp. 22 ◽  
Author(s):  
David Michael Bourne
Keyword(s):  
Language Learning ◽  
Language Proficiency ◽  
Educational Institutions ◽  
Human Element ◽  
Use Of Technology ◽  
The One ◽  
Impact Of Technology ◽  
Age Range ◽  
The Impact

Technology has an ever increasing impact on how we work and live. Article adressed the issue of the impact of technology in two key areas of language learning. On the one side learners increasingly used technology to translate. Given this trend, was there any real need to learn a language. On the other side, educational institutions increasingly used technology to rate language proficiency. Given this trend, would the work of the teacher become less and less important. The survey was conducted by using quantitative method. The respondents’ age range was 18-25. There were 53 respondents, 35% were male and 65% were female. The instrument was a questionaire having 9 questions describing the students’ reliance on computer in translation. It can be concluded that learners of English indicate that they accept and welcome the role of technology in language learning, but there is a doubt that the role and participation of humans in the learning process will be completely replaced. The human element remains an important ingredient. (EE)

scholarly journals Inferring recent evolutionary changes in speech sounds

2021 ◽  
Vol 376 (1824) ◽  
Author(s):  
Steven Moran ◽  
Nicholas A. Lester ◽  
Eitan Grossman
Keyword(s):  
Language Contact ◽  
Language Evolution ◽  
Speech Sounds ◽  
Theme Issue ◽  
Short Term ◽  
The Past ◽  
Evolutionary Changes ◽  
The One ◽  
The Impact

In this paper, we investigate evolutionarily recent changes in the distributions of speech sounds in the world's languages. In particular, we explore the impact of language contact in the past two millennia on today's distributions. Based on three extensive databases of phonological inventories, we analyse the discrepancies between the distribution of speech sounds of ancient and reconstructed languages, on the one hand, and those in present-day languages, on the other. Furthermore, we analyse the degree to which the diffusion of speech sounds via language contact played a role in these discrepancies. We find evidence for substantive differences between ancient and present-day distributions, as well as for the important role of language contact in shaping these distributions over time. Moreover, our findings suggest that the distributions of speech sounds across geographic macro-areas were homogenized to an observable extent in recent millennia. Our findings suggest that what we call the Implicit Uniformitarian Hypothesis, at least with respect to the composition of phonological inventories, cannot be held uncritically. Linguists who would like to draw inferences about human language based on present-day cross-linguistic distributions must consider their theories in light of even short-term language evolution. This article is part of the theme issue ‘Reconstructing prehistoric languages’.

scholarly journals Energy Saving as an Important Factor in Ensuring Product Competitiveness

2021 ◽  
Vol 2 (48) ◽  
pp. 120-125
Author(s):  
O. P. Vashkiv ◽  
◽  
S. B. Smereka ◽  
Keyword(s):  
Energy Saving ◽  
Specific Energy Consumption ◽  
Environmental Standards ◽  
Manufacturing Enterprise ◽  
Research Results ◽  
Industrial Enterprises ◽  
The Face ◽  
The One ◽  
The Impact

The article is aimed at studying the features of energy saving at a manufacturing enterprise and establishing a cause-and-effect relationship between energy saving and product competitiveness. Due to analyzing and generalizing the research results of domestic and foreign scientists the views of researchers on the process of energy saving at a manufacturing enterprise are systematized; the growing role of energy saving in ensuring energy efficiency and, consequently, product competitiveness is established. The research results show that energy saving at an enterprise is one of its most important assets, the impact of which on the level of product competitiveness is becoming increasingly important in the face of the exacerbating energy and environmental crises. Energy saving, basically focusing on the intensification of production processes and use of energy and energy resources, on the one hand, reduces the level of specific energy consumption and, consequently, the price of the released product while maintaining or increasing its quality; on the other hand, it reduces the carbon loading on the environment, thus contributes to the growth of the company's image among its consumers and partners. Both components are the most important factors in ensuring product competitiveness. The development and implementation of energy saving measures at industrial enterprises, with regard to the industry-specific character of economic entities, market conditions, and the requirements of environmental standards can serve as prospects for further research

scholarly journals Sustaible Ethanol Production From Sugarcane Molasses by Saccharomyce scerevisiae Immobilized on Chitosan-Coated Manganese Ferrite

2021 ◽  
Vol 5 ◽  
Author(s):  
Arianna Núñez Caraballo ◽  
Anna Iliná ◽  
Rodolfo Ramos González ◽  
Cristóbal N. Aguilar ◽  
Georgina Michelena Álvarez ◽  
...  
Keyword(s):  
Ethanol Production ◽  
Yeast Cells ◽  
Manganese Ferrite ◽  
X Ray Diffraction ◽  
Sugar Consumption ◽  
Total Consumption ◽  
Fermentation Time ◽  
Open Questions ◽  
One Step ◽  
The One

The interaction between nanostructures and yeast cells, as well as the description of the effect of nanoparticles in ethanol production are open questions in the development of this nanobiotechnological process. The objective of the present study was to evaluate the ethanol production by Saccharomyces cerevisiae in the free and immobilized state on chitosan-coated manganese ferrite, using cane molasses as a carbon source. To obtain the chitosan-coated manganese ferrite, the one-step coprecipitation method was used. The nanoparticles were characterized by X-ray diffraction obtaining the typical diffraction pattern. The crystal size was calculated by the Scherrer equation as 15.2 nm. The kinetics of sugar consumption and ethanol production were evaluated by HPLC. With the immobilized system, it was possible to obtain an ethanol concentration of 56.15 g/L, as well as the total sugar consumption at 24 h of fermentation. Productivity and yield in this case were 2.3 ± 0.2 g/(L * h) and 0.28 ± 0.03, respectively. However, at the same time in the fermentation with free yeast, 39.1 g/L were obtained. The total consumption of fermentable sugar was observed only after 42 h, reaching an ethanol titer of 50.7 ± 3.1, productivity and yield of 1.4 ± 0.3 g/(L * h) and 0.25 ± 0.4, respectively. Therefore, a reduction in fermentation time, higher ethanol titer and productivity were demonstrated in the presence of nanoparticles. The application of manganese ferrite nanoparticles shows a beneficial effect on ethanol production. Research focused on the task of defining the mechanism of their action and evaluation of the reuse of biomass immobilized on manganese ferrite in the ethanol production process should be carried out in the future.

Preparation of nanocellulose by hydrolysis with ionic liquids and two-step hydrolysis with ionic liquids and enzymes

2021 ◽  
Vol 116 ◽  
pp. 5-14
Author(s):  
Marta Babicka ◽  
Magdalena Woźniak ◽  
Kinga Szentner ◽  
Sławomir Borysiak ◽  
Krzysztof Dwiecki ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Degree Of Crystallinity ◽  
Cellulolytic Enzyme ◽  
X Ray Diffraction ◽  
Production Methods ◽  
Step Process ◽  
X Ray ◽  
One Step ◽  
Xrd Patterns ◽  
The One

The aim of this study was to compare parameters of nanocellulose obtained by two different procedures: hydrolysis with ionic liquids (1-allyl-3-methylimidazolium chloride and 1-ethyl-3-methylimidazolium acetate) and hydrolysis with ionic liquids in combination with hydrolysis using a cellulolytic enzyme from Trichoderma reesei. Avicel cellulose was treated with two ionic liquids: 1-allyl-3-methylimidazolium chloride (AmimCl) and 1-ethyl 3-methylimidazolium acetate (EmimOAc). In the two-step hydrolysis cellulose after treatment with ionic liquids was additionally hydrolyzed with a solution of enzymes. In order to characterize the obtained material, the following analyses were used: infrared spectroscopy, X-ray diffraction and dynamic light scattering. The results indicated that cellulose obtained by two-step nanocellulose production methods (first hydrolysis with ionic liquids and then with enzymes) showed similar parameters (particle size, XRD patterns and degree of crystallinity) as the material after the one-step process, i.e. hydrolysis with ionic liquids.

Sign in / Sign up

Export Citation Format

Share Document