scholarly journals Progress in Vinyl Acetate

CONVERTER ◽  
2021 ◽  
pp. 861-867
Author(s):  
Heng Ma
Keyword(s):  
Vinyl Acetate ◽  
Synthesis Method ◽  
Raw Material ◽  
Organic Chemical ◽  
Synthesis Methods ◽  
Advantages And Disadvantages ◽  
Production Route ◽  
Film Adhesive ◽  
Development Direction ◽  
Adhesive Coating

Vinyl acetate is an organic chemical raw material of great industrial value. It is widely used in synthetic film, adhesive, coating and textile slurry. The production route of vinyl acetate is introduced, and the advantages and disadvantages of synthesis methods of vinyl acetate method, acetylene method, EDA cracking method, base synthesis method and Halcon method are compared. The method of carbide acetylene has high economic efficiency, low energy consumption and good environmental protection, proposing the development direction of ethylene acetate production technology.

scholarly journals Methods for synthesis of matching circuits for broadband radio devices with unstable load impedance

Doklady BGUIR ◽  
2021 ◽  
Vol 19 (1) ◽  
pp. 61-69
Author(s):  
I. A. Dubovik ◽  
P. V. Boykachev ◽  
V. O. Isaev ◽  
A. A. Dmitrenko
Keyword(s):  
Transfer Coefficient ◽  
Power Transmission ◽  
Synthesis Method ◽  
Synthesis Methods ◽  
Power Transfer ◽  
Load Impedance ◽  
Advantages And Disadvantages ◽  
Power Transmission Coefficient ◽  
Broadband Matching ◽  
Comparison Of The Results

The aim of this work is to select a synthesis method for a broadband matching circuit that provides maximum power transfer from a signal source to a load in the presence of a changing load impedance of a radio engineering device. To achieve this goal, an analysis of the main directions of designing broadband matching circuits (analytical, numerical, graphic-analytical synthesis methods) was carried out. Based on the results of a comparison of synthesis methods, their features (advantages and disadvantages) were indicated. The analysis of methods of synthesis of broadband matching circuits was carried out. For the analysis, the generalized Darlington method, the method of real frequencies, the structural-parametric synthesis method based on the T-matrix apparatus, and the graphic-analytical method based on the Volpert-Smith diagram were chosen). Using these synthesis methods, broadband matching circuits were obtained for various types of loads. Comparison of the results obtained was carried out according to several indicators: the level of the power transfer coefficient in the operating frequency range, the sensitivity of the power transfer coefficient to the change in the ratings of the elements of the matching circuit and the load impedance, provided that the number of elements of the matching circuit is no more than six. Based on the comparison and analysis, it was found that the most preferable synthesis method for solving the problem posed is the method of real frequencies. Its advantage is the use of a combination approach (iterative determination of the parameters of the resistance function with an analytical representation of the transfer function). Matching circuits obtained using this synthesis method provided the highest level of power transmission coefficient, as well as the lowest sensitivity value in a given frequency band for the considered types of loads.

scholarly journals Simulation and improvement of the separation process of synthesizing vinyl acetate by acetylene gas-phase method

2021 ◽  
Vol 10 (1) ◽  
pp. 912-922
Author(s):  
Qiuli Zhang ◽  
Zhaoyang Chen ◽  
Ziyue Song ◽  
Jun Zhou ◽  
Xiaogang Ning ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Vinyl Acetate ◽  
Polyvinyl Acetate ◽  
Raw Material ◽  
Phase Method ◽  
Organic Chemical ◽  
Reflux Ratio ◽  
Excessive Heat ◽  
Classical Design ◽  
Separation Equipment

Abstract Vinyl acetate, as an essential organic chemical raw material, can be used to produce polyvinyl acetate, polyester vinyl alcohol, and other products. The existing classical vinyl acetate production process has the problems of low product purity and excessive heat load. In this study, in the classical design of the process, acetylene is separated first, and then acetaldehyde is removed with the formation of an azeotrope between ethylene acetate and water. Meanwhile, considering the solubility of acetaldehyde in water and insolubility of vinyl acetate in water, the process was optimized to separate acetic acid after removing acetylene, so as to avoid the azeotrope formation of vinyl acetate and water. The nonrandom two-liquid-Hayden–O’Connell thermodynamic hybrid model was used to simulate the classical process and improved process (IP). Finally, the reflux ratio and theoretical tray number of the main separation equipment of IP were optimized to get the better parameters. The simulated results show that the purity of vinyl acetate increased from 99.1% to 99.8%, the cooling energy consumption was reduced by 16.83%, and the thermal energy consumption was reduced by 6.18%. At the same time, the equipment investment was also decreased.

Metallic Nanoparticle Synthesis by Green Chemistry

2018 ◽  
Vol 11 (6) ◽  
pp. 4287-4294
Author(s):  
Anikate Sood ◽  
Shweta Agarwal
Keyword(s):  
Green Chemistry ◽  
Green Synthesis ◽  
Biomedical Research ◽  
Metallic Nanoparticles ◽  
Nanoparticle Synthesis ◽  
Synthesis Methods ◽  
Metallic Nanoparticle ◽  
Medical Field ◽  
Advantages And Disadvantages ◽  
Gold Silver

Nanotechnology is the most sought field in biomedical research. Metallic nanoparticles have wide applications in the medical field and have gained the attention of various researchers for advanced research for their application in pharmaceutical field. A variety of metallic nanoparticles like gold, silver, platinum, palladium, copper and zinc have been developed so far. There are different methods to synthesize metallic nanoparticles like chemical, physical, and green synthesis methods. Chemical and physical approaches suffer from certain drawbacks whereas green synthesis is emerging as a nontoxic and eco-friendly approach in production of metallic nanoparticles. Green synthesis is further divided into different approaches like synthesis via bacteria, fungi, algae, and plants. These approaches have their own advantages and disadvantages. In this article, we have described various metallic nanoparticles, different modes of green synthesis and brief description about different metabolites present in plant that act as reducing agents in green synthesis of metallic nanoparticles. 

scholarly journals Interrelations of Synthesis Method, Polyethylene Glycol Coating, Physico-Chemical Characteristics, and Antimicrobial Activity of Silver Nanoparticles

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2475
Author(s):  
Amirah Shafilla Mohamad Kasim ◽  
Arbakariya Bin Ariff ◽  
Rosfarizan Mohamad ◽  
Fadzlie Wong Faizal Wong
Keyword(s):  
Antimicrobial Activity ◽  
Silver Nanoparticles ◽  
Polyethylene Glycol ◽  
Pathogenic Bacteria ◽  
Synthesis Method ◽  
Chemical Characteristics ◽  
Synthesis Methods ◽  
Uniform Size ◽  
Transmission Electron Microscopy Analysis ◽  
Physico Chemical

Silver nanoparticles (AgNPs) have been found to have extensive biomedical and biological applications. They can be synthesised using chemical and biological methods, and coated by polymer to enhance their stability. Hence, the changes in the physico-chemical characteristics of AgNPs must be scrutinised due to their importance for biological activity. The UV-Visible absorption spectra of polyethylene glycol (PEG) -coated AgNPs displayed a distinctive narrow peak compared to uncoated AgNPs. In addition, High-Resolution Transmission Electron Microscopy analysis revealed that the shapes of all AgNPs, were predominantly spherical, triangular, and rod-shaped. Fourier-Transform Infrared Spectroscopy analysis further confirmed the role of PEG molecules in the reduction and stabilisation of the AgNPs. Moreover, dynamic light scattering analysis also revealed that the polydispersity index values of PEG-coated AgNPs were lower than the uncoated AgNPs, implying a more uniform size distribution. Furthermore, the uncoated and PEG-coated biologically synthesised AgNPs demonstrated antagonisms activities towards tested pathogenic bacteria, whereas no antagonism activity was detected for the chemically synthesised AgNPs. Overall, generalisation on the interrelations of synthesis methods, PEG coating, characteristics, and antimicrobial activity of AgNPs were established in this study.

scholarly journals Sol-Gel Synthesis of the Double Perovskite Sr2FeMoO6 by Microwave Technique

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3876
Author(s):  
Jesús Valdés ◽  
Daniel Reséndiz ◽  
Ángeles Cuán ◽  
Rufino Nava ◽  
Bertha Aguilar ◽  
...  
Keyword(s):  
Particle Size ◽  
Hydrothermal Synthesis ◽  
Microwave Radiation ◽  
Structural Characteristics ◽  
Sol Gel ◽  
Synthesis Method ◽  
Double Perovskite ◽  
Synthesis Methods ◽  
X Ray ◽  
Sol Gel Synthesis

The effect of microwave radiation on the hydrothermal synthesis of the double perovskite Sr2FeMoO6 has been studied based on a comparison of the particle size and structural characteristics of products from both methods. A temperature, pressure, and pH condition screening was performed, and the most representative results of these are herein presented and discussed. Radiation of microwaves in the hydrothermal synthesis method led to a decrease in crystallite size, which is an effect from the reaction temperature. The particle size ranged from 378 to 318 nm when pH was 4.5 and pressure was kept under 40 bars. According to X-ray diffraction (XRD) results coupled with the size-strain plot method, the product obtained by both synthesis methods (with and without microwave radiation) have similar crystal purity. The Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS) techniques showed that the morphology and the distribution of metal ions are uniform. The Curie temperature obtained by thermogravimetric analysis indicates that, in the presence of microwaves, the value was higher with respect to traditional synthesis from 335 K to 342.5 K. Consequently, microwave radiation enhances the diffusion and nucleation process of ionic precursors during the synthesis, which promotes a uniform heating in the reaction mixture leading to a reduction in the particle size, but keeping good crystallinity of the double perovskite. Precursor phases and the final purity of the Sr2FeMoO6 powder can be controlled via hydrothermal microwave heating on the first stages of the Sol-Gel method.

scholarly journals Microwave-Assisted vs. Conventional Hydrothermal Synthesis of MoS2 Nanosheets: Application towards Hydrogen Evolution Reaction

Crystals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1040 ◽  
Author(s):  
Getachew Solomon ◽  
Raffaello Mazzaro ◽  
Vittorio Morandi ◽  
Isabella Concina ◽  
Alberto Vomiero
Keyword(s):  
Hydrothermal Synthesis ◽  
Hydrothermal Method ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Current Density ◽  
Crystal Morphology ◽  
Synthesis Method ◽  
Synthesis Methods ◽  
Mos2 Nanosheets ◽  
Microwave Assisted

Molybdenum sulfide (MoS2) has emerged as a promising catalyst for hydrogen evolution applications. The synthesis method mainly employed is a conventional hydrothermal method. This method requires a longer time compared to other methods such as microwave synthesis methods. There is a lack of comparison of the two synthesis methods in terms of crystal morphology and its electrochemical activities. In this work, MoS2 nanosheets are synthesized using both hydrothermal (HT-MoS2) and advanced microwave methods (MW-MoS2), their crystal morphology, and catalytical efficiency towards hydrogen evolution reaction (HER) were compared. MoS2 nanosheet is obtained using microwave-assisted synthesis in a very short time (30 min) compared to the 24 h hydrothermal synthesis method. Both methods produce thin and aggregated nanosheets. However, the nanosheets synthesized by the microwave method have a less crumpled structure and smoother edges compared to the hydrothermal method. The as-prepared nanosheets are tested and used as a catalyst for hydrogen evolution results in nearly similar electrocatalytic performance. Experimental results showed that: HT-MoS2 displays a current density of 10 mA/cm2 at overpotential (−280 mV) compared to MW-MoS2 which requires −320 mV to produce a similar current density, suggesting that the HT-MoS2 more active towards hydrogen evolutions reaction.

Material Properties and Design Aspects of Folding Bicycle Frame

2011 ◽  
Vol 264-265 ◽  
pp. 777-782 ◽  
Author(s):  
M.A. Maleque ◽  
M.S. Hossain ◽  
S. Dyuti
Keyword(s):  
Material Properties ◽  
Raw Material ◽  
New Materials ◽  
Materials Properties ◽  
Advantages And Disadvantages ◽  
Bicycle Frame ◽  
Successful Design ◽  
Future Direction ◽  
The Relationship ◽  
Comprehensive Study

successful design of folding bicycle should take into account the function, material properties, and fabrication process. There are some other factors that should be considered in anticipating the behavior of materials for folding bicycle. In order to understand the relationship between material properties and design of a folding bicycle and also for the future direction in new materials with new design, a comprehensive study on the design under different conditions are essential. Therefore, a systematic study on the relationship between material properties and design for folding bicycle has been performed. The advantages and disadvantages matrix between conventional bicycle and folding bicycle is presented for better understanding of the materials properties and design. It was found that the materials properties of the folding bicycle frame such as fatigue and tensile strength are the important properties for the better performance of the frame. The relationship between materials properties and design is not straight forward because the behavior of the material in the finished product could be different from that of the raw material. The swing hinge technique could be a better technique in the design for the folding bicycle frame.

COMPARING AND IMPROVING THE SYNTHESIS OF STATE-BASED SPECIFICATIONS FROM SCENARIO-BASED SPECIFICATIONS

2012 ◽  
Vol 22 (07) ◽  
pp. 867-890
Author(s):  
ZHIJIAN WANG ◽  
WENRUI LI ◽  
PENGCHENG ZHANG
Keyword(s):  
Synthesis Method ◽  
The State ◽  
Experimental Comparison ◽  
Synthesis Methods ◽  
User Requirements ◽  
State Machines ◽  
Analysis Method ◽  
Improved Method ◽  
Local Synthesis ◽  
Novel Algorithm

The scenario-based specifications are popularly used to capture user requirements. The state-based specifications are very appropriate to capture system design. Recently, there has been increased research interest in connecting these two kinds of specifications, called synthesis. Synthesis is a way to automatically construct the state-based specifications from the scenario-based specifications. There are two kinds of synthesis methods: global synthesis and local synthesis. Global synthesis means constructing a state-based specification for the whole system from the scenario-based specifications, while local synthesis means constructing a state-based specification for each object in the system. The two different synthesis methods have different uses and need to be systematically compared. The contributions of this paper are twofold. Firstly, we propose an improved method supporting the global and the local synthesis of state machines (a kind of state-based specifications) by using a novel algorithm for state machine execution and an algorithm similar to operator priority analysis method, which can fully automate the process of synthesis. Our synthesis method also satisfies two important properties: completeness and soundness. Secondly, to the best of our knowledge, our work does the first attempt to systematically compare global synthesis with local synthesis, and shows some insightful results of the experimental comparison between the two kinds of synthesis methods, which are valuable for the practitioners to choose an appropriate synthesis method for the analysis and verification of the system.

Flame-retardant properties of ethylene-vinyl acetate/oil sludge/ fumed silica composites

RSC Advances ◽  
2016 ◽  
Vol 6 (67) ◽  
pp. 63091-63098 ◽  
Author(s):  
Yi Qian ◽  
Xiaoyan Zhu ◽  
Shanshan Li ◽  
Xilei Chen
Keyword(s):  
Flame Retardant ◽  
Vinyl Acetate ◽  
Fumed Silica ◽  
Ethylene Vinyl Acetate ◽  
Raw Material ◽  
Oil Sludge ◽  
Flame Retardant Properties

Ethylene-vinyl acetate (EVA)/oil sludge (OS)/fumed silica (SiO2) composites were synthesized using OS containing CaCO3as raw material.

scholarly journals Review on the Synthesis Methods of Nano-Tungsten Oxide Dihydrate Colloid

2021 ◽  
Vol 335 ◽  
pp. 03008
Author(s):  
Khizar Mushtaq ◽  
Pui May Chou ◽  
Chin Wei Lai
Keyword(s):  
Particle Size ◽  
Tungsten Oxide ◽  
Sol Gel ◽  
Synthesis Method ◽  
Transition Element ◽  
Cost Effective ◽  
Processing Parameters ◽  
Synthesis Methods ◽  
Cost Effective Method ◽  
Future Work

Tungsten being a transition element, forms oxide compounds of various oxidation states that enables it to form nanocolloids of tungsten oxide dihydrate. Multiple methods have been used in recent years to synthesize nano tungsten oxide dihydrate, including sol-gel synthesis, electrochemical deposition, hydrothermal synthesis and anodization. However, a universally accepted synthesis method for this material is not offered. The most appropriate method and its corresponding processing parameters for the synthesis of nano tungsten oxide dihydrate colloids were presented in the present study. The objective of the present study was to investigate the effect of processing parameters, i.e. applied voltage, temperature and anodizing duration on the particle size of nanocolloids. It is found that anodization is the easiest, efficient, and cost-effective method to synthesize the colloidal solution of nano tungsten oxide dihydrate. Conducting the synthesis at room temperature at a voltage of 50 V for 60 minutes yields the product with particle size of 40 – 60 nm, which can be used in wide array of applications. This paper also highlights the research gaps for future work and gives recommendations to extend this study particularly for the industrial application of tungsten oxide.

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