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Topic Review
Reaction Mechanisms of Glycerol Hydrogenolysis to 1,2-Propylene Glycol
The development and growth of the biodiesel industry has led to a parallel market for the supply of glycerol, its main by-product. Its wide availability and relatively low cost as a raw material make glycerol a basic component for obtaining various chemical products and allows for the development of a biorefinery around biodiesel plants, through the technological integration of different production processes. Catalytic hydrogenolysis is an interesting alternative because it leads to the formation of 1,2-propylene glycol (1,2-PG) and other glycols such as 1,3-propylene glycol (1,3-PG) and ethylene glycol (EG), widely used in the chemical industry. In the following text, the main reaction mechanisms of glycerol hydrogenolysis are presented, focusing on the production of 1,2-PG, in order of chronological appearance.
  • 769
  • 10 May 2023
Topic Review
Self-Assembling Nucleobase-Containing Peptides
The self-assembly of bio-inspired nanomaterials and biological nanostructures confers new properties and functions to conjugated biomaterials, such as the ability to respond to external stimuli. Nucleobase-containing peptides can be considered as aromatic peptides and, similar to these self-assembling structures, they can lead to interesting functional nanostructures as hereafter explained. Self-assembling nucleopeptides can form hydrogels based on supramolecular structures held by non-covalent molecular interactions occurring between the peptide segments, as well as π–π stacking and Watson–Crick interactions via complementary DNA bases.
  • 769
  • 16 Jun 2021
Topic Review
Permafrost Carbon Cycle
The permafrost carbon cycle is a sub-cycle of the larger global carbon cycle. Permafrost is defined as subsurface material that remains below 0o C (32o F) for at least two consecutive years. Because permafrost soils remain frozen for long periods of time, they store large amounts of carbon and other nutrients within their frozen framework during that time. Permafrost represents a large carbon reservoir that is seldom considered when determining global terrestrial carbon reservoirs. Recent and ongoing scientific research however, is changing this view. The permafrost carbon cycle (Arctic Carbon Cycle) deals with the transfer of carbon from permafrost soils to terrestrial vegetation and microbes, to the atmosphere, back to vegetation, and finally back to permafrost soils through burial and sedimentation due to cryogenic processes. Some of this carbon is transferred to the ocean and other portions of the globe through the global carbon cycle. The cycle includes the exchange of carbon dioxide and methane between terrestrial components and the atmosphere, as well as the transfer of carbon between land and water as methane, dissolved organic carbon, dissolved inorganic carbon, particulate inorganic carbon and particulate organic carbon.
  • 769
  • 04 Nov 2022
Topic Review
Seaweeds Compounds
Seaweeds’ compounds present important qualities for cosmetic application, such as low cytotoxicity and low allergens content. Several seaweeds’ molecules already demonstrated a high potential as a cosmetic active ingredient (such as, mycosporine-like amino acids, fucoidan, pigments, phenolic compounds) or as a key element for the products consistency (agar, alginate, carrageenan). Moreover, it focuses on the ecological and sustainable scope of seaweed exploitation to guarantee a safe source of ingredients for the cosmetic industry and consumers.
  • 768
  • 17 Jan 2022
Topic Review
Basic Nanoarchitectonics
Although various synthetic methodologies including organic synthesis, polymer chemistry, and materials science are the main contributors to the production of functional materials, the importance of regulation of nanoscale structures for better performance has become clear with recent science and technology developments. Therefore, a new research paradigm to produce functional material systems from nanoscale units has to be created as an advancement of nanoscale science. This task is assigned to an emerging concept, nanoarchitectonics, which aims to produce functional materials and functional structures from nanoscale unit components. This can be done through combining nanotechnology with the other research fields such as organic chemistry, supramolecular chemistry, materials science, and bio-related science. In this review article, the basic-level of nanoarchitectonics is first presented with atom/molecular-level structure formations and conversions from molecular units to functional materials. Then, two typical application-oriented nanoarchitectonics efforts in energy-oriented applications and bio-related applications are discussed. Finally, future directions of the molecular and materials nanoarchitectonics concepts for advancement of functional nanomaterials are briefly discussed.
  • 768
  • 27 May 2021
Topic Review
Current Challenges and Perspectives for Biomass Catalytic Pyrolysis
Lignocellulosic biomass is an excellent alternative of fossil source owing to the fact that it is low-cost, plentiful and environmentally friendly. Through pyrolysis, lignocellulosic biomass can be converted into the potential precusor of liquid fuel or platform chemicals. Therefore, the detailed knowledge and mechanism about biomass conversion should be overviewed and concluded. We have reviewed several factors which impact the conversion of biomass, including the properties of biomass, operational parameters of catalytic pyrolysis and different types of pyrolysis equipment. Meantime, some perspectives for future development have been proposed in the end.
  • 768
  • 13 Dec 2022
Topic Review
Nanotechnological Smart Food Packaging
Polymer nanocomposites (PNCs) are of real interest because along with the bioactivity induced by the components (or by the polymer itself), these materials due to the composite nature can exhibit some improved physical, chemical, biological, mechanical, electrical, and optical properties compared to individual components [1]. Due to the innovative properties such as maintaining the quality and safety of food but also increasing the shelf-life of the food, nanocomposite packaging has great potential as an innovative food packaging technology. The polymer nanocomposites used in developing food packaging materials are mainly composed of the polymer matrix, nanofillers, plasticizers, and compatibilizers.
  • 768
  • 02 Sep 2020
Topic Review
Fischer–Tropsch Synthesis for Light Olefins
Light olefins as one the most important building blocks in chemical industry can be produced via Fischer–Tropsch synthesis (FTS) from syngas. FT synthesis conducted at high temperature would lead to light paraffins, carbon dioxide, methane, and C5+ longer chain hydrocarbons. The present work focuses on providing a critical review on the light olefin production using Fischer–Tropsch synthesis.
  • 767
  • 07 Aug 2021
Topic Review
Copper-Coated Used Fuel Container
The Copper Coated Used Fuel Container is the main containment barrier in the engineered barrier system. The role of copper coated used fuel container is to provide containment for used CANDU (CANada Deuterium Uranium) fuel and any other fuel deemed acceptable for a deep geological repository in accordance with the Nuclear Fuel Waste Act (S.C. 2002, c.23) and Nuclear Waste Management Organization’s waste acceptance criteria.
  • 767
  • 07 Dec 2021
Topic Review
Modification of Glucomannan as an Excipient
Glucomannan (GM) is a polysaccharide generally extracted from the tuber of Amorphophallus konjac. It consists of mannose and glucose residues linked by β-(1-4) and exhibits hydrocolloid characteristics which can be applied as thickening and gelling agents. However, it has poor water resistance and low mechanical strength when used as an excipient in solid form. Several physical and chemical modifications have been carried out to improve these drawbacks. Chemical modification involves the substitution of functional groups in GM’s structure including esterification and etherification. It causes a decrease in its high hydrophilic film behavior and produce water-resistant films. Physical modification involves mixing native GM with other excipients through processes involving milling, moisture, temperature, pressure, radiation, etc. It causes variations to particle size, shape, surface properties, porosity, density, and to functional properties such as swelling capacity and gelation ability
  • 767
  • 26 Jul 2022
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