scholarly journals Selectivity Control of C-O Bond Cleavage for Catalytic Biomass Valorization

2022 ◽  
Vol 9 ◽  
Author(s):  
Yumei Jian ◽  
Ye Meng ◽  
Hu Li

Increasing fossil fuels consumption and global warming have driven the global revolution towards renewable energy sources. Lignocellulosic biomass is the main source of renewable carbon-based fuels. The abundant intermolecular linkages and high oxygen content between cellulose, hemicellulose, and lignin limit the use of traditional fuels. Therefore, it is a promising strategy to break the above linkages and remove oxygen by selective catalytic cracking of C–O bond to further transform the main components of biomass into small molecular products. This mini-review discusses the significance of selectivity control in C–O bond cleavage with well-tailored catalytic systems or strategies for furnishing biofuels and value-added chemicals of high efficiency from lignocellulosic biomass. The current challenges and future opportunities of converting lignocellulose biomass into high-value chemicals are also summarized and analyzed.

2021 ◽  
Author(s):  
Chikako Asada ◽  
Sholahuddin ◽  
Yoshitoshi Nakamura

Recently, plant biomass has been attracting attention due to global warming and the depletion of fossil fuels. Lignocellulosic biomass (i.e., wood, straw, and bagasse) is attracting attention as an abundant renewable resource that does not compete with the food resources. It is composed of cellulose, hemicellulose, and lignin and is a potential resource that can be converted into high-value-added substances, such as biofuels, raw materials for chemical products, and cellulose nanofibers. However, due to its complicated structure, an appropriate pretreatment method is required for developing its biorefinery process. Steam explosion is one of the simplest and environmentally friendly pretreatments to decompose lignin structure, which converts cellulose into low-molecular-weight lignin with high efficiency. It has received significant attention in the field of not only biofuel but also biochemical production. Steam explosion involves the hydrolysis of plant biomass under high-pressure steam and the sudden release of steam pressure induces a shear force on the plant biomass. Moreover, it is a green technology that does not use any chemicals. Thus, a steam explosion-based biorefinery system is highly effective for the utilization of lignocellulosic into useful materials, such as ethanol, methane gas, antioxidant material, epoxy resin, and cellulose nanofiber.


Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1234
Author(s):  
Zhiwei Jiang ◽  
Di Hu ◽  
Zhiyue Zhao ◽  
Zixiao Yi ◽  
Zuo Chen ◽  
...  

Efficient conversion of renewable biomass into value-added chemicals and biofuels is regarded as an alternative route to reduce our high dependence on fossil resources and the associated environmental issues. In this context, biomass-based furfural and levulinic acid (LA) platform chemicals are frequently utilized to synthesize various valuable chemicals and biofuels. In this review, the reaction mechanism and catalytic system developed for the generation of furfural and levulinic acid are summarized and compared. Special efforts are focused on the different catalytic systems for the synthesis of furfural and levulinic acid. The corresponding challenges and outlooks are also observed.


2021 ◽  
Author(s):  
M. Amin Farkhondehfal ◽  
Juqin Zeng

The CO2 that comes from the use of fossil fuels accounts for about 65% of the global greenhouse gas emission, and it plays a critical role in global climate changes. Among the different strategies that have been considered to address the storage and reutilization of CO2, the transformation of CO2 into chemicals and fuels with a high added-value has been considered a winning approach. This transformation is able to reduce the carbon emission and induce a “fuel switching” that exploits renewable energy sources. The aim of this chapter is to categorize different heterogeneous electrocatalysts which are being used for CO2 reduction, based on the desired products of the above mentioned reactions: from formic acid and carbon monoxide to methanol and ethanol and other possible by products. Moreover, a brief description of the kinetic and mechanism of the CO2 reduction reaction) and pathways toward different products have been discussed.


1997 ◽  
Vol 37 (1) ◽  
pp. 722
Author(s):  
N.G. Grollman

The oil and gas reserves of Australia and the East Asian region fall well short of the region's long-term requirements, even for a scenario that phases out all fossil fuels by the end of the 21st century. There is, therefore, no contradiction between vigorous exploration for oil and gas and the process of transition to renewable energy sources. However, to be an independent player in environmental policy-making, the Australian petroleum exploration industry should focus on its particular role within the energy sector as a whole, whose nature will change radically over the next several decades. This role will combine concerns over long term oil supply security with, in particular, the objective of reducing greenhouse gas emissions from oil and gas consumption to levels commensurate with Australia's international obligations. The role extends to Australian involvement in the region as a whole through the accrual of emissions credits from projects implemented jointly with developing countries. It also envisages that Australian explorers, especially those focussed on gas, will form alliances with downstream companies, power generators, appliance manufacturers and energy marketers as links in an integrated chain of operations with value added and emissions reduced at each stage. This re-orientation should lead the industry to question the extent to which its interests correspond with those of the coal and mineral industries, which do not face the same resource limitations.


Declining supplies of fossil fuels, increasing population, global industrialization, and demand for transportation fuels have triggered an increase in the demand for renewable energy sources. To address such problems most of the green research in recent years has focused on the development of bioethanol (23 MJ/L) as a substitute to conventional gasoline (34.3 MJ/L) based fuels owing to the similarity in energy density values in addition to several other advantages (American Council on renewable energy, 2010). Second-generation biofuels are derived from lignocellulosic biomass or woody crops, mostly coming from agricultural residues. Extraction of fuel from such biomass is difficult because of their recalcitrant nature (corn stover, rice straw, wheat straw, sugar cane, and sweet sorghum). Lignocellulosic fuel has the potential to solve several problems (food competing with fuel) that are currently associated with first-generation biofuels. Moreover, lignocellulosic fuels can supply a larger proportion of the global fuel leading to sustainability at a lower cost, and with greater environmental benefits (Liz Marsall, 2009). The production of ethanol from the complex sugars in leaves and stalks is a promising strategy to radically broaden the range of possible ethanol feedstock.


Author(s):  
Marta Goliszek ◽  
Beata Podkościelna

<p>The overutilization of fossil fuels will inevitably cause the global environmental problems and dwindling of available resources. For that reason, identifying renewable sustainable alternatives has attracted an increasing attention. Lignocellulosic biomass has been considered to be one of the most logical feedstock to replace traditional fossil resources as one of the most accessible renewable forms of carbon. One of the primary components of lignocellulosic biomass, next to hemicellulose and cellulose is lignin. It is a by-product in paper and pulp industry. Lignin is mainly used as fuel directly, without further utilization which is suggested to be a waste of natural resources. With this purpose, the valorization of lignin into value-added products needs particular attention of researchers. This review article focuses on chosen possible applications of lignin in chemical industry.</p>


Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3902 ◽  
Author(s):  
R. Guil-López ◽  
N. Mota ◽  
J. Llorente ◽  
E. Millán ◽  
B. Pawelec ◽  
...  

Technological approaches which enable the effective utilization of CO2 for manufacturing value-added chemicals and fuels can help to solve environmental problems derived from large CO2 emissions associated with the use of fossil fuels. One of the most interesting products that can be synthesized from CO2 is methanol, since it is an industrial commodity used in several chemical products and also an efficient transportation fuel. In this review, we highlight the recent advances in the development of heterogeneous catalysts and processes for the direct hydrogenation of CO2 to methanol. The main efforts focused on the improvement of conventional Cu/ZnO based catalysts and the development of new catalytic systems targeting the specific needs for CO2 to methanol reactions (unfavourable thermodynamics, production of high amount of water and high methanol selectivity under high or full CO2 conversion). Major studies on the development of active and selective catalysts based on thermodynamics, mechanisms, nano-synthesis and catalyst design (active phase, promoters, supports, etc.) are highlighted in this review. Finally, a summary concerning future perspectives on the research and development of efficient heterogeneous catalysts for methanol synthesis from CO2 will be presented.


Molecules ◽  
2019 ◽  
Vol 24 (4) ◽  
pp. 786 ◽  
Author(s):  
Rehman Javaid ◽  
Aqsa Sabir ◽  
Nadeem Sheikh ◽  
Muhammad Ferhan

Processing of fossil fuels is the major environmental issue today. Biomass utilization for the production of chemicals presents an alternative to simple energy generation by burning. Lignocellulosic biomass (cellulose, hemicellulose and lignin) is abundant and has been used for variety of purposes. Among them, lignin polymer having phenyl-propanoid subunits linked together either through C-C bonds or ether linkages can produce chemicals. It can be depolymerized by fungi using their enzyme machinery (laccases and peroxidases). Both acetic acid and formic acid production by certain fungi contribute significantly to lignin depolymerization. Fungal natural organic acids production is thought to have many key roles in nature depending upon the type of fungi producing them. Biological conversion of lignocellulosic biomass is beneficial over physiochemical processes. Laccases, copper containing proteins oxidize a broad spectrum of inorganic as well as organic compounds but most specifically phenolic compounds by radical catalyzed mechanism. Similarly, lignin peroxidases (LiP), heme containing proteins perform a vital part in oxidizing a wide variety of aromatic compounds with H2O2. Lignin depolymerization yields value-added compounds, the important ones are aromatics and phenols as well as certain polymers like polyurethane and carbon fibers. Thus, this review will provide a concept that biological modifications of lignin using acidophilic fungi can generate certain value added and environmentally friendly chemicals.


2021 ◽  
Vol 22 (1&2) ◽  
pp. 87-95
Author(s):  
Mohd Ishfaq Bhat ◽  
Navin Chandra Shahi ◽  
Umesh Chand Lohani ◽  
Anil Kumar ◽  
Sheeba Malik

Lignocellulosic biomass (like rice straw) provides an alternative for depleting non-renewable energy sources through its value-added utilization (like production of biofuels and nanocellulose) owing to its abundance, renewability, polymer presence and environmental friendliness. Prior to its utilization, any lignocellulosic biomass is subjected to a time-consuming delignification process for lignin free biomass recovery. The present study aims to reduce the time of delignification of rice straw along with enhancing the delignification percentage of biomass by use of microwave assisted sodium chlorite method. The experiments were done at two microwave power levels (640, 800 W), three bleaching solution concentrations (0.4, 1.7, 3.0 %) and three microwave treatment times (4, 8, 12 min). The delignification percentage of the rice straw for the whole experimentation varied from 24.7 to 90.12%. The results revealed that the time of delignification was greatly reduced (12 min) with a very high delignification (90.12%) percentage. The morphology of the delignified samples also revealed the deconstruction of the lignin structure. The improved method can thus be applied for the delignification of other biomasses as well for quick and effective delignification


2019 ◽  
Vol 23 (20) ◽  
pp. 2168-2179 ◽  
Author(s):  
Yufei Xu ◽  
Jingxuan Long ◽  
Jian He ◽  
Hu Li

With the depletion of fossil energy, liquid biofuels are becoming one of the effective alternatives to replace fossil fuels. The catalytic transfer and hydrogenation of biomass-based furanic compounds into fuels and value-added chemicals has become a spotlight in this field. Gas hydrogen is often used as the H-donor for the hydrogenation reactions. It is a very straightforward and simple method to implement, but sometimes it comes with the danger of operation and the difficulty of regulation. In recent years, diverse liquid hydrogen donor reagents have been employed in the catalytic transfer hydrogenation (CTH) of biomass. Amongst those H-donors, alcohol is a kind of green and benign reagent that has been used in different biomass conversion reactions. This type of reagent is very convenient to use, and the involved operation process is safe, as compared to that of H2. In this review, the application of alcohols as liquid H-donors in the catalytic transfer hydrogenation of biomass-derived furanic compounds is depicted, and the representative reaction mechanisms are discussed. Emphasis is also laid on the selective control of product distribution in the described catalytic systems.


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