A Short Review on the Synthesis of Polylactic Acid by Reactive Extrusion and Static Mixing Reaction Techniques

2021 ◽  
Vol 13 (2) ◽  
pp. 181-187
Author(s):  
Rong Liu ◽  
Yue Zhao
Keyword(s):  
Polylactic Acid ◽  
Large Scale ◽  
Reactive Extrusion ◽  
Short Review ◽  
Synthetic Methods ◽  
Scale Production ◽  
Synthesis Mechanism ◽  
Advantages And Disadvantages ◽  
Large Scale Production ◽  
Twin Screw

Polylactic acid (PLA) is one of the most attractive biodegradable polymers, but the large-scale production of PLA in most countries is still in its infancy. This review begins with a brief introduction to PLA synthesis mechanism, followed by a summary of the techniques of twin-screw reactive extrusion and tubular static mixing reaction, which are two new methods for rapid synthesis of PLA with large-scale production potential. The structures, advantages and disadvantages of each technique are then reviewed in the paper. Finally, the rapid synthetic methods are prospected.

scholarly journals Biotechnological valorization of agro industrial and household wastes for lactic acid production

2019 ◽  
Vol 21 (1) ◽  
pp. 113-127 ◽  
Author(s):  
Juliana Romo-Buchelly ◽  
María Rodríguez-Torres ◽  
Fernando Orozco-Sánchez
Keyword(s):  
Lactic Acid ◽  
Large Scale ◽  
Lactic Acid Production ◽  
Scale Production ◽  
Advantages And Disadvantages ◽  
Large Scale Production ◽  
Different Types ◽  
High Transformation ◽  
Transformation Potential ◽  
The Cost

Lactic acid (LA) is an organic compound used in several industries, such as food, textile, chemical, and pharmaceutical. The global interest  in  this  product  is  due  to  its  use  for  the  synthesis  of  numerous  chemical  compounds,  including  polylactic  acid,  a  biode-gradable thermoplastic and substitute for petroleum-derived plastics. An in-depth overview of the use of industrial and household wastes as inexpensive substrates in order to reduce the cost of LA production is presented. A review is carried out of the biotech-nological aspects that must be taken into account when using some wastes with high transformation potential to produce LA in a submerged  culture,  as  well  recommendations  for  their  use.  The  advantages  and  disadvantages  of  different  types  of  treatments used for the transformation of waste into suitable substrates are considered. Several methods of fermentation, as well as genetic strategies for increasing the production, are summarized and compared. It is expected that in a few years there will be many ad-vances in these areas that will allow greater large-scale production of LA using agroindustrial or household wastes, with potential positive economic and environmental impact in some regions of the planet.

Effect of chemical and enzymatic treatments of alfa fibers on polylactic acid bio-composites properties

2020 ◽  
Vol 54 (30) ◽  
pp. 4959-4967
Author(s):  
Mouna Werchefani ◽  
Catherine Lacoste ◽  
Hafedh Belguith ◽  
Ali Gargouri ◽  
Chedly Bradai
Keyword(s):  
Large Scale ◽  
Natural Fiber ◽  
Poly Lactic Acid ◽  
Homogeneous Distribution ◽  
Scale Production ◽  
Fiber Modification ◽  
Large Scale Production ◽  
Twin Screw ◽  
Alfa Fibers ◽  
Fiber Matrix

Poor interfacial adhesion between vegetable fibers and bio-based thermoplastics is recognized as a serious drawback for biocomposite materials. To be applicable for a large-scale production, one should consider appropriate methods of natural fiber handling. This study presented poly(lactic acid) (PLA) reinforced with Alfa short fibers and four types of fiber treatment were selected. The effect of these treatments on the tensile properties and the morphology of biocomposites was studied. Composite samples were produced using a twin-screw extruder and an injection molding machine with a fiber percentage of 20 wt %. Prior to composite manufacture, Alfa fibers were subjected to mechanical, chemical and enzymatic modifications. The comparison of enzyme treated fibers and NaOH treated fibers was investigated by means of biochemical and morphological analyses. It was observed that enzymes decompose lignin, pectin and hemicelluloses from the fiber bundles interface leading to the reduction of technical fiber diameter and length. The elimination of these hydrophilic components resulted also in an increase of the water resistance of treated fibers. A bigger fiber-matrix interface area was thus created, which facilitated fiber-matrix adhesion and enhanced mechanical characteristics of the composites. SEM micrographs showed homogeneous distribution of treated fibers in the polymer matrix. Tensile strength of PLA biocomposites filled with pectinase treated fibers was increased by 27% over untreated samples. The data proved that enzymatic treatment can be used as an effective and ecofriendly strategy of fiber modification for natural fiber-reinforced composite production. These materials can be used in several domains such as construction, automotive applications and packaging industries.

Amines via Hydroaminomethylation: An Updated Overview

2021 ◽  
Vol 25 ◽  
Author(s):  
Carmela G. Arena
Keyword(s):  
Large Scale ◽  
Synthetic Methods ◽  
Catalytic Process ◽  
Scale Production ◽  
Tertiary Amines ◽  
Atom Economy ◽  
Reaction Conditions ◽  
One Pot ◽  
Large Scale Production ◽  
The Cost

: Aliphatic secondary and tertiary amines are widely used in the production of pharmaceuticals, agrochemicals, dyes, surfactants and rubber chemicals. Most traditional synthetic methods are often unsuitable for large-scale production due to poor selectivity, harsh reaction conditions and the cost of starting materials. In this context, hydroaminomethylation (HAM) is a very attractive catalytic process with high atom economy that starts from inexpensive reagents, such as alkenes. This review aims to provide an updated overview of hydroaminomethylation as a useful tool for synthesizing aliphatic secondary and tertiary amines. Therefore, the discussion will focus on both unsaturated starting compounds and the amines obtained by this one-pot reaction.

scholarly journals An Overview of the Photocatalytic Water Splitting over Suspended Particles

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 60
Author(s):  
Muhammad Amtiaz Nadeem ◽  
Mohd Adnan Khan ◽  
Ahmed Abdeslam Ziani ◽  
Hicham Idriss
Keyword(s):  
Water Splitting ◽  
Large Scale ◽  
Cost Effective ◽  
Synthetic Methods ◽  
Scale Production ◽  
Practical Applications ◽  
Co Catalysts ◽  
Large Scale Production ◽  
Cost Effective Method ◽  
Order Of Magnitude

The conversion of solar to chemical energy is one of the central processes considered in the emerging renewable energy economy. Hydrogen production from water splitting over particulate semiconductor catalysts has often been proposed as a simple and a cost-effective method for large-scale production. In this review, we summarize the basic concepts of the overall water splitting (in the absence of sacrificial agents) using particulate photocatalysts, with a focus on their synthetic methods and the role of the so-called “co-catalysts”. Then, a focus is then given on improving light absorption in which the Z-scheme concept and the overall system efficiency are discussed. A section on reactor design and cost of the overall technology is given, where the possibility of the different technologies to be deployed at a commercial scale and the considerable challenges ahead are discussed. To date, the highest reported efficiency of any of these systems is at least one order of magnitude lower than that deserving consideration for practical applications.

scholarly journals Microbial production of melanin and its various applications

2020 ◽  
Vol 36 (11) ◽  
Author(s):  
Anh N. Tran-Ly ◽  
Carolina Reyes ◽  
Francis W. M. R. Schwarze ◽  
Javier Ribera
Keyword(s):  
Organic Semiconductors ◽  
Large Scale ◽  
Production Method ◽  
Scale Production ◽  
Biological Processes ◽  
Advantages And Disadvantages ◽  
The Past ◽  
Large Scale Production ◽  
Real World Applications ◽  
Adverse Environmental Conditions

Abstract Melanins are natural biopolymers that are known to contribute to different biological processes and to protect organisms from adverse environmental conditions. During the past decade, melanins have attracted increasing attention for their use in organic semiconductors and bioelectronics, drug delivery, photoprotection and environmental bioremediation. Although considerable advances in these fields have been achieved, real-world applications of melanins are still scarce, probably due to the limited and expensive source of natural melanin. Nevertheless, recent biotechnological advances have allowed for relatively large-scale production of microbial melanins, which could replace current commercial melanin. In this review, we first describe different melanin sources and highlight the advantages and disadvantages of each production method. Our focus is on the microbial synthesis of melanins, including the methodology and mechanism of melanin formation. Applications of microbial melanins are also discussed, and an outlook on how to push the field forward is discussed.

I. S. A. Baud. Forms of Production and Women's Labour: Gender Aspects of Industrialisation in India and Mexico. New Delhi: Sage Publications. 1992. 321 pp.Hardbound. Price: Indian Rs 295.00.

1993 ◽  
Vol 32 (1) ◽  
pp. 129-131
Author(s):  
Naureen Talha
Keyword(s):  
Large Scale ◽  
Indian Society ◽  
New Delhi ◽  
Scale Production ◽  
Female Labour ◽  
Self Employment ◽  
Commodity Production ◽  
Large Scale Production ◽  
Mexican Society ◽  
Small Production

The literature on female labour in Third World countries has become quite extensive. India, being comparatively more advanced industrially, and in view of its size and population, presents a pictures of multiplicity of problems which face the female labour market. However, the author has also included Mexico in this analytical study. It is interesting to see the characteristics of developing industrialisation in two different societies: the Indian society, which is conservative, and the Mexican society, which is progressive. In the first chapter of the book, the author explains that he is not concerned with the process of industrialisation and female labour employed at different levels of work, but that he is interested in forms of production and women's employment in large-scale production, petty commodity production, marginal small production, and self-employment in the informal sector. It is only by analysis of these forms that the picture of females having a lower status is understood in its social and political setting.

An Efficient and Improved Process for the Synthesis of Itopride Hydrochloride and Trimethobenzamide Hydrochloride

2018 ◽  
Vol 15 (4) ◽  
pp. 572-575 ◽  
Author(s):  
Ponnusamy Kannan ◽  
Samuel I.D. Presley ◽  
Pallikondaperumal Shanmugasundaram ◽  
Nagapillai Prakash ◽  
Deivanayagam Easwaramoorthy
Keyword(s):  
Large Scale ◽  
Hydroxylamine Hydrochloride ◽  
Scale Production ◽  
One Pot ◽  
Hydrochloride Salt ◽  
Environmental Friendly ◽  
Large Scale Production ◽  
Non Ulcer Dyspepsia ◽  
Itopride Hydrochloride ◽  
Yield And Purity

Aim and Objective: Itopride is a prokinetic agent used for treating conditions like non-ulcer dyspepsia. Itopride is administered as its hydrochloride salt. Trimethobenzamide is used for treating nausea and vomiting and administered as its hydrochloride salt. The aim is to develop a novel and environmental friendly method for large-scale production of itopride and trimethobenzamide. Materials and Methods: Itopride and trimethobenzamide can be prepared from a common intermediate 4- (dimethylaminoethoxy) benzyl amine. The intermediate is prepared from one pot synthesis using Phyrdroxybenzaldehye and zinc dust and further reaction of the intermediate with substituted methoxy benzoic acid along with boric acid and PEG gives itopride and trimethobenzamide. Results: The intermediate 4-(dimethylaminoethoxy) benzylamine is prepared by treating p-hydroxybenzaldehyde and 2-dimethylaminoethyl chloride. The aldehyde formed is treated with hydroxylamine hydrochloride. The intermediate is confirmed by NMR and the purity is analysed by HPLC. Conclusion: Both itopride and trimethobenzamide were successfully synthesized by this method. The developed method is environmental friendly, economical for large-scale production with good yield and purity.

scholarly journals Cyanobacteria—From the Oceans to the Potential Biotechnological and Biomedical Applications

Marine Drugs ◽  
2021 ◽  
Vol 19 (5) ◽  
pp. 241
Author(s):  
Shaden A. M. Khalifa ◽  
Eslam S. Shedid ◽  
Essa M. Saied ◽  
Amir Reza Jassbi ◽  
Fatemeh H. Jamebozorgi ◽  
...  
Keyword(s):  
Bioactive Compounds ◽  
Biomedical Applications ◽  
Large Scale ◽  
Biological Activities ◽  
Scale Production ◽  
Pharmacological Activities ◽  
Large Scale Production ◽  
Marine Products ◽  
Hiv 1 ◽  
Successful Phase

Cyanobacteria are photosynthetic prokaryotic organisms which represent a significant source of novel, bioactive, secondary metabolites, and they are also considered an abundant source of bioactive compounds/drugs, such as dolastatin, cryptophycin 1, curacin toyocamycin, phytoalexin, cyanovirin-N and phycocyanin. Some of these compounds have displayed promising results in successful Phase I, II, III and IV clinical trials. Additionally, the cyanobacterial compounds applied to medical research have demonstrated an exciting future with great potential to be developed into new medicines. Most of these compounds have exhibited strong pharmacological activities, including neurotoxicity, cytotoxicity and antiviral activity against HCMV, HSV-1, HHV-6 and HIV-1, so these metabolites could be promising candidates for COVID-19 treatment. Therefore, the effective large-scale production of natural marine products through synthesis is important for resolving the existing issues associated with chemical isolation, including small yields, and may be necessary to better investigate their biological activities. Herein, we highlight the total synthesized and stereochemical determinations of the cyanobacterial bioactive compounds. Furthermore, this review primarily focuses on the biotechnological applications of cyanobacteria, including applications as cosmetics, food supplements, and the nanobiotechnological applications of cyanobacterial bioactive compounds in potential medicinal applications for various human diseases are discussed.

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