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Catalytic Conversion of Lignocellulosic Biomass into Fuels and Value-Added Chemicals
Published in Sonil Nanda, Prakash Kumar Sarangi, Dai-Viet N. Vo, Fuel Processing and Energy Utilization, 2019
Shireen Quereshi, Suman Dutta, Tarun Kumar Naiya
On the contrary, application of concentrated mineral acids may lead to corrosion problems in the reactor, catalyst recycling problem, and excessive by-product formation. Therefore, attempts have been made to use mineral acids such as H2SO4 in a low quantity. Table 3.1 summarizes different catalysts used for the production of HMF. Recently, Zuo et al. (2017) have reported the production of HMF using a deep eutectic solvent (DES) made from extremely low concentrations of either HCl or H2SO4 with choline chloride. Consequently, 88.6% HMF yield was measured in the presence of H2SO4 containing DES at 100°C for 240 minutes in an oil bath reactor. Interestingly, when HCl alone was used as the catalyst, a significant HMF yield (57 %) from fructose was found within a short reaction time of 40 minutes at 100°C (Garce et al. 2017).
Nonaqueous Redox Flow Batteries
Published in Huamin Zhang, Huamin Zhang, Xianfeng Li, Jiujun Zhang, Redox Flow Batteries, 2017
Copper, iron, and zinc chloro complexes are mainly based on a deep eutectic solvent of choline chloride and ethylene glycol [39–43]. This system has metals in very high concentration but slow mass transport and low electrolyte conductivity. Moreover, the OCP in this all-copper system is estimated to be 0.75 V. In an all-iron system, it is around 1.1 V, which is not higher than that of iron reactions in aqueous systems. In the Zn-Fe system, an enhanced energy efficiency (EE) of 78% can be obtained at a current density of 0.5 mAcm−2. Subsequently, the electrolyte for this system was optimized. The 2:0:4 (iron chloride : choline chloride : ethylene glycol) electrolyte contained 6.3 M iron, and the 1:1:4 one showed a conductivity of 12.7 mScm–2 and a low viscosity of 17.8 cP (80°C).
Fabrication processes
Published in Frédéric Guittard, Thierry Darmanin, Bioinspired Superhydrophobic Surfaces, 2017
Frédéric Guittard, Thierry Darmanin
In order to better control the surface structures, a deep eutectic solvent consisting of a mixture of choline chloride and ethylene glycol was used as the electrolyte [369]. Various structured architectures such as nanosheets, aligned nanostrips, and hierarchical flowers were obtained as a function of the electrodeposition method (constant potential, pulsed potential, and reverse pulse potential) [370371]. The highest superhydrophobic properties (θw = 164°, Hw = 4°) were reached with nanosheets obtained at a constant potential. Sponge-like structures made of interconnected nanofibers of nickel hydroxides Ni(OH)2 were also produced in a basic solution using CH3COONa. After post-treatment, the substrates displayed both high transparency and superhydrophobic properties with low water adhesion. It was also reported the possibility of reversibly switching from superhydrophobic to superhydrophilic by UV/ozone and heat treatments.
Physical properties of deep eutectic solvents based on p-toluene sulfonic acid and employment as catalyst
Published in Chemical Engineering Communications, 2023
Shan Jiang, Zuoxiang Zeng, Weilan Xue, Zhijie Mao, Ying Wang
The “green chemistry” concept has been extensively recognized in the chemical industry since its first appearance in the early 1990s (Marco et al. 2019). In order to reduce the environmental pollution caused by traditional solvents or catalysts, exploring greener alternatives has become the main target of chemical production (Alder et al. 2016). In this context, ionic liquids (ILs) are synthesized and simply defined as organic molten salts (melting point: below 100 °C) composed of only ions (Earle and Seddon 2000; Prat et al. 2014). ILs have received great attention due to their unique merits, such as high polarity, wide liquid range, high solubility and non-flammability (Plechkova and Seddon 2008; Olivier-Bourbigou et al. 2010; Nasirpour et al. 2020). However, the industrial application of ILs is limited because of their corrosiveness, toxicity and difficulty in recycling (Abbott et al. 2004; Wells and Coombe 2006). To overcome these disadvantages while the similar favorable properties to ILs are retained, deep eutectic solvent (DES) has been developed and has become a new alternative with excellent properties (including biodegradability, nontoxic, easy preparation and purification) (Juneidi et al. 2015).
Biocoatings and additives as promising candidates for ultralow friction systems
Published in Green Chemistry Letters and Reviews, 2021
Marcia Gabriely A. da Cruz, Tetyana M. Budnyak, Bruno V. M. Rodrigues, Serhiy Budnyk, Adam Slabon
Studies have proven that superlubricity can be achieved with the use of lubricants (33, 136, 137) as a solution to overcome the constraints of the ambient conditions. Water–based lubricants combined with 2D nanomaterials additives are able to maintain low COF for long periods. Even though limitations still exist related to load-bearing capacity by using water-based lubricants, they could be overcome by substitution with ionic liquids (IL), whose load capacity, electrochemical widow, and thermal stability favor low friction (136, 138–140). Moreover, the association of IL and DLC is attractive to generate lubrication systems with low friction (141, 142). Nevertheless, when it comes to sustainability, ILs do not figure as a good option due to their toxicity and low biodegradability (143, 144). In this context, deep eutectic solvent (DES) appears as an alternative, sharing properties with IL and overcoming the sustainability issues (145, 146). Another promising solvent that is similar to ILs is the natural deep eutectic solvent (NADES), which is a DES composed of natural, readily available, and biorenewable compounds (147).