Impact of formic/acetic acid and ammonia pre-treatments on chemical structure and physico-chemical properties of Miscanthus x giganteus lignins

2011 ◽  
Vol 96 (10) ◽  
pp. 1761-1770 ◽  
Author(s):  
Caroline Vanderghem ◽  
Aurore Richel ◽  
Nicolas Jacquet ◽  
Christophe Blecker ◽  
Michel Paquot
Hydrobiologia ◽  
1991 ◽  
Vol 221 (1) ◽  
pp. 137-148 ◽  
Author(s):  
Marc Lahaye ◽  
Cyrille Rochas

2017 ◽  
Vol 744 ◽  
pp. 441-445
Author(s):  
Norhafiza Mohd Salleh ◽  
Siti Halimah Sarijo ◽  
Anizah Kalam

A herbicide, 3,4-Dichlorophenoxy acetic acid (34D) was successfully intercalated into the zinc layered hydroxide (ZLH) by direct reaction with zinc oxide (ZnO) to form a new organic-inorganic zinc layered hydroxide-3,4-Dichlorophenoxy acetate (Z34D) under an aqueous environment. The pH of the solution was adjusted to 7.5 using 2 M sodium hydroxide (NaOH). The pure phase and well-ordered was synthesized at 0.3 M Z34D. PXRD patterns show well-ordered nanohybrid material with basal spacing at 26.1 Å. The percentage loading of 34D in the Z34D is 57.5 % (w/w) calculated based on the percentage of carbon in the sample. FESEM shows the ZnO precursor has very fine granular structure and transformed into agglomerate structure when the nanohybrid are formed. This work shows that the nanohybrid of Z34D can be synthesized using simple, direct-reaction method.


2020 ◽  
Vol 45 (5) ◽  
Author(s):  
G.O . Madojemu ◽  
E.A. Elimian ◽  
M.C. Ejimadu ◽  
C.O. Okieimen ◽  
F.E. Okieimen

Biolubricant base stock was synthesized in this work from rubber seed oil in a one-pot-two-step process of epoxidation and hydroxylation. Rubber seed oil was extracted using a Soxhlet apparatus. The in situ epoxidation of the rubber seed oil with peracid (hydrogen peroxide and acetic acid) was analysed and optimized considering three process variables with their range of values given as temperature of 35-50 , time of 60-180 mins and mole ratio of hydrogen peroxide to acetic acid of 1:0.25-1:1 by applying the central composite design of response surface methodology. The ring opening reaction (hydroxylation) of the epoxide to polyhydroxylated oil (lubricant basestock) with ethanol was carried out using the optimum conditions obtained from the epoxidation process. The rubber seed oil, epoxide and lubricant basestock were characterized in terms of physico-chemical properties using standard methods and in terms of functional groups using Fourier Transform Infrared (FTIR) spectroscopy. Maximum epoxide content of 4.85% and maximum conversion of 71% of rubber seed oil to epoxide was achieved at a temperature of 50􀀀 , reaction time of 180 mins and 1: 0.39 mol/mol of hydrogen peroxide to acetic acid. The predicted values of the epoxidation process reasonably agreed with the experimental ones and model R-squared value of about 95% showed that response surface method can reasonably predict the epoxidation process using a quadratic polynomial model. There was 75% conversion of the epoxide to polyhydroxylated oil (biolubricant basestock), which represents a very high yield. The formation of epoxides and polyhydroxylated oil lead to modification (improvement) in the properties of rubber seed oil as confirmed by the physico-chemical properties and FTIR spectra analysis of the oil, epoxide and lubricant basestock. The study showed that chemical derivatives of rubber seed oils are an attractive, renewable, and ecofriendly alternative to mineral oils for lubricant formulations.


Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1205
Author(s):  
Agnieszka Piotrowska-Kirschling ◽  
Joanna Brzeska

Materials science is an interdisciplinary area of studies. This science focuses on the influence of the physico-chemical properties of materials on their application in human everyday lives. The materials’ synthesis should be developed in accordance with sustainable development. Polyurethanes (PUR) represent a significant consumption of plastic in the world. Modification of PUR, e.g., with polysaccharide of natural origin (chitosan, Chit), should have a positive effect on their functional properties and degradability in the natural environment. The basic parameters affecting the scope and direction of changes are the size and quantity of the chitosan particles. The impact assessment of chitosan on the chemical structure, morphology, thermal properties, crystallinity, mechanical properties, flammability, water sorption, adsorption properties, degradability, and biological activity of PUR/Chit composites (without other additives) is discussed in this article. To the best of our knowledge, recent literature does not contain a study discussing the direct impact of the presence of chitosan in the structure of PUR/Chit composite on its properties, regardless of the intended uses. This paper provides an overview of publications, which presents the results of a study on the effect of adding chitosan in polyurethane/chitosan composites without other additives on the properties of polyurethane.


2004 ◽  
Vol 2 (4) ◽  
pp. 638-647 ◽  
Author(s):  
Luminita Balau ◽  
Gabriela Lisa ◽  
M. Popa ◽  
V. Tura ◽  
V. Melnig

AbstractChitosan films obtained by dry phase inversion were prepared from an aqueous solution of chitosan in acetic acid. The films, of thickness less than 20 μm, were transparent, very flexible and had smooth surfaces. Increasing the film thickness induced an increase of the internal tensions and the consequent formation of a rough surface. Structural investigations by X-ray diffraction and Fourier transform IR analysis, showed that the chitosan films, as prepared, are amorphous. Further annealing to evaporate acetic acid and water traces, changed the amorphous phase into a more ordered phase, characterized by diffraction peaks at 2θ values of 9, 17, 20 and 23 degrees. Thermal investigations by TG, DTG, and DTA revealed that the decomposition of the chitosan films as prepared proceeds in two stages, starting from 180°C and 540°C.


2021 ◽  
pp. 21-33
Author(s):  
Premy Puspitawati Rahayu ◽  
Abdul Manab ◽  
Manik Eirry Sawitri ◽  
Ria Dewi Andriani ◽  
Mulia Winirsya Apriliyani ◽  
...  

Aims: The purpose of this research was to investigate the influence of physicochemical properties of interaction casein with different concentration catechin sources of the cocoa husk. Study design: Casein was added catechin with various concentration treatments (0 (control), 20, 40 and 60 (μg/ml)). Place and Duration of Study: This study was conducted between April until August 2020 at the Faculty of Animal Science, Universitas Brawijaya. Methodology: Casein was added catechin with various concentration treatments (0, 20, 40 and 60 (μg/ml)). An analysis is carried out to determine interaction using UV-Vis detection, chemical structure using Fourier Transform Infra-Red, microscopy analysis by Scanning Electron Microscopy, particle size by Zetasizer Nano Series Software Version 7.01, Malvern Instrument and electrophoretic analysis. Results: The interaction between casein and catechin was investigated by the method of UV-Vis detection and chemical structure analysis by Fourier Transform Infra-Red showed that it was indicated that catechin could detected in casein. It is similar with recent research. The interaction of casein and catechin showed to decrease the particle size and showed on microscopy analysis. Protein profile showed to increase the molecular weight with the addition of catechin, it can be indicated that presence interaction both on casein with catechin. Conclusion: Casein interacted with catechins 60 µg/ml was able to increase casein stability, maintain nano size, casein components were still detected in the protein profile, the resulting microstructure looked compact and functional groups of bioactive compounds were still detected using Fourier Transform Infra-Red.


Mathematics ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 42 ◽  
Author(s):  
Jia-Bao Liu ◽  
Muhammad Kashif Shafiq ◽  
Haidar Ali ◽  
Asim Naseem ◽  
Nayab Maryam ◽  
...  

A topological index is a numerical representation of a chemical structure, while a topological descriptor correlates certain physico-chemical characteristics of underlying chemical compounds besides its numerical representation. A large number of properties like physico-chemical properties, thermodynamic properties, chemical activity, and biological activity are determined by the chemical applications of graph theory. The biological activity of chemical compounds can be constructed by the help of topological indices such as atom-bond connectivity (ABC), Randić, and geometric arithmetic (GA). In this paper, Randić, atom bond connectivity (ABC), Zagreb, geometric arithmetic (GA), ABC4, and GA5 indices of the mth chain silicate S L ( m , n ) network are determined.


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