Decomposition Of Organic Solvents Research Articles

Experimental investigation and thermomechanical performance evaluation of supercritical water oxidation of n‐dodecane/tributyl phosphate

AbstractBACKGROUNDNuclear energy has brought immense benefits while also generating a large amount of wastewater that urgently needs to be processed. Supercritical water oxidation (SCWO) technology serves as an efficient method for wastewater treatment. In this study, a SCWO experiment was carried out with organic solvent of 30% tributyl phosphate (TBP) and 70% n‐dodecane. This study investigated the operating parameters and the effects of enhanced oxidation techniques on chemical oxygen demand (COD) removal efficiency. An organic solvent SCWO process was developed, and its energy and exergy efficiencies were assessed using Aspen Plus.RESULTSThe COD removal was about 96.18% at the experimental parameters of 500 °C, 10 min, 25 MPa, oxidation coefficient of 1.5 and material concentration of 4 wt%. COD removal increased by 3.09% with the addition of CeO2. Finally, the overall energy and exergy efficiencies of the SCWO system were found to be 58.8% and 9.1% respectively by Aspen Plus.CONCLUSIONIt was found that the reaction temperature had the greatest effect on the COD removal rate compared with other reaction parameters. The decomposition of organic solvents can be divided into two stages, fast and slow, and the addition of alkali and catalyst can effectively promote the decomposition of waste organic solvents. The experiments showed that SCWO is feasible for the treatment of n‐dodecane/TBP. © 2024 Society of Chemical Industry (SCI).

Mechanistic Study of the Effect of Epoxy Groups on Ethylene Carbonate Decomposition Reaction on Carbon Anodes of Sodium-Ion Batteries

The formation of solid-electrolyte interphase (SEI) layers which results from the decomposition of organic solvents in the electrolyte on the anode of sodium-ion batteries (SIBs) is crucial and mus...

A Liquid Anode of Lithium Biphenyl for Highly Safe Lithium‐Air Battery with Hybrid Electrolyte

AbstractA hybrid electrolyte, by uniting aqueous and organic electrolyte with a water‐stable lithium super ionic conductor ceramic (LISICON) plate, was proposed to circumvent the drawbacks of nonaqueous Li‐air batteries, such as corrosion of metallic Li from humidity, decomposition of organic solvents and insoluble discharge products clogging air electrode. However, safety issues deteriorate when the brittle ceramic plate fails to separate organic and aqueous solutions. This study aimed to improve the safety of the hybrid electrolyte based Li‐air battery, by designing a liquid anode of lithium biphenyl (LiBP) replacing the lithium metal as the mild reaction between LiBP and aqueous electrolyte without combustion. Moreover, sputtering Ti layer onto the anodic side of the ceramic plate can improve chemical stability of interface between the liquid anode and solid electrolyte. In this system, the cell exhibited a relatively high discharge voltage of 2.81 V at the current density of 0.5 mA cm−2, as well as a specific power of 1638 W kg−1 at the current density of 6 mA cm−2 by using this liquid anode. The cycling life exceeded over 120 cycles at the current density of 0.5 mA cm−2. The ex situ Raman spectrometry and in situ GC‐MS analyses reveal that the redox reaction of BP−/BP and OH−/O2 in anolyte and catholyte respectively can deliver large capacity during cycling.

The Effect of Epoxy Group on Ethylene Carbonate Decomposition at Carbon Anode of Sodium Ion Batteries: Theoretical Study

Sodium-ion batteries (SIBs) have received much attention as promising alternatives to Li-ion batteries as large scale and low-cost energy storage systems owing to close electrochemical similarity between lithium and sodium, and the natural abundance of sodium resources. However, many challenges must be overcome to make SIBs well-positioned in commercialization such as low cyclability, and low stability of the solid-electrolyte interphase (SEI) formation, results from the decomposition of organic solvents in the electrolyte on the anode of SIBs. The SEI has a profound effect on cycle life and performance of the batteries. Therefore, understanding the SEI compositions and its formation mechanisms is crucial for SIBs development. Carbon-based anode materials are commonly used as the anode for SIBs because of their appropriate electrochemical properties, an abundance of carbon and safety. The oxygen-containing groups often present in the carbon-based anode and they usually actively involved in chemical reactions. In this work, we performed density functional theory (DFT) calculations to elucidate the effect of oxygen containing group of epoxy on decomposition mechanisms at the initial stages of sodiation of ethylene carbonate (EC) molecule which is one of common electrolytes applied in ion-battery. The calculation results indicated that EC decompositions on pristine graphene were initiated by CE-OE bond cleavage which is rate-limiting step followed by Cc-OE bond cleavage in the second step producing CO2 and acetaldehyde as products (Figure 1). The presence of an epoxy group on graphene does not directly change the mechanisms, however, it significantly increased the activation barriers on all decomposition pathways compared to those on pristine graphene. The strong electrostatic interaction between negatively charged epoxy group and positively charged Na ion weakens interaction between EC and carbon surface. Also, the presence of an epoxy group facilitates carbon surface to be more positively charged and electron transfer to EC is less favorable than that on pristine graphene. Furthermore, we investigated the solvation effect on the mechanisms by increase the number of EC molecules to model a solvation shell. The results showed that the inclusion of the electrolyte environment reveals other possible decomposition mechanisms including proton transfer from EC molecule to epoxy group producing hydroxyl group on carbon surface prior to the EC ring-opening reaction step. This work suggests that the presence of oxygenated functional group on anode carbon surface and solvent environment can have significant effects on EC decomposition mechanisms both thermodynamic and kinetic aspects. Including the electrolyte solvation shell is crucial for electrolyte decomposition investigation using molecular modeling. Figure 1

Super lithiophilic SEI derived from quinones electrolyte to guide Li uniform deposition

Metallic lithium with high theoretical specific capacity is usually regarded as an attractive electrode material for high-energy-density batteries. However, the wide practical applications of lithium metal batteries are severely limited by the random metallic lithium accumulation on a working lithium anode. Here, tetrachloro-1,4-benzoquinone (TCBQ) was adapted as an electrolyte additive, which possesses the relatively low lowest unoccupied molecular orbital and can generate quinone lithium salt (Li2TCBQ) in SEI layer during cycling. According to the molecular dynamics simulations, Li2TCBQ is lithiophilic that can serve as the lithium plating guidance to regulate uniform lithium deposition relying on the high lithium-ion affinity. The cell with TCBQ-added electrolyte can be deeply cycled at a high capacity of 5 mAh cm−2 without formation of isolated lithium, and decomposition of organic solvents during cycling in carbonate electrolyte is suppressed effectively. The use of TCBQ additive offers a new approach to realize high energy-density lithium metal batteries.

In Ukrainian

The catalytic system “carbon nanotubes/peroxide molecule” in aqueous/non-aqueous media was investigated for determining of the main factors that influence on catalyst’s effectiveness. The catalytic activity of as-synthesized multi-walled carbon nanotubes, and their modified forms (oxidized and nitrogen doped) were investigated in the decomposition of hydrogen, benzoyl (BP) and lauroyl (LP) peroxides at room temperature by measuring the volume of released gases. Ethyl acetate and tetrachloromethane were used for BP and LP decomposition respectively. Among factors that determined the catalytic performance of investigated samples their structural-sorption properties, surface chemistry and diffusion limitation have been considered. It was established that CNT show moderate activity in aqueous medium because of internal diffusion limitation. As a consequence, their performance is determined by the textural characteristic of carbon matrices. Based on the calculated diffusion coefficients it was concluded that catalysis by CNT in non-aqueous area is carried out in the kinetic region on their accessible surface. Such catalytically active surface has a lot of N-containing functional groups as well as basic O-containing ones, therefore it shows better activity towards organic peroxides. Moreover, CNT’s surface is more hydrophobic that is promoting the reaction proceeding in non-aqueous media. The decomposition rate of steric BP is lower compared to the long chain of LP. Based on this finding, it could be predicted that mesoporous CNT with high content basic functionalities and good surface accessibility should be the excellent catalyst for diacyl peroxides decomposition in organic solvents.

Three-dimensional nanoporous organic frameworks based on rigid unites

With rigid 1,3,5,7-Tetrakis(4-bromophenyl)adamantane (TBPA) and 3,3′,5,5′,7,7′-Hexa(4-bromophenyl)-1,1′-biadamantane (HBPBA) separately coupling with 4,4′-Bisethynylstilene and 4,4′-Bisethynltolan, porous polymers (T1, T2, H1, and H2) were successfully synthesized. The obtained polymers have high surface area (755 m2 g−1) and superior thermal stability (their initial decomposition temperature under N2 condition could reach to 400 °C). In addition, the polymers show ultra-high chemical stability (no apparent decomposition in organic solvents for more than 96 h). At 1.0 bar (273 K), their uptake of CO2, N2, CH4, C2H2 and C2H4 could reach to 11.0 wt%, 1.5 wt%, 6.2 wt% and 7.2 wt%, respectively. Moreover, they also can absorb a large amount of vapor molecules at 298 K, with the largest values up to 232 mg g−1 (benzene), 196 mg g−1 (cyclohexane) and 169 mg g−1 (hexane) when P/P0 = 0.8. The adsorption selectivity for CO2/N2 is 42.6 and for CO2/CH4 is 4.25. These combined properties render the synthesized polymers an attractive candidate as chemical stable adsorbents for practical use in gas storage, gas separation and pollutant vapor adsorption.

In English

The aim of this study is to investigate the catalytic system “Carbon nanomaterial-diacyl peroxide molecule-non-aqueous medium” and determine main factors that influence on carbon catalyst’s effectiveness. The catalytic activity of nanoporous (activated carbon (AC)) and nanosized (multiwalled carbon nanotubes (CNT)) carbon catalysts and their modified forms were investigated in the decomposition of benzoyl and lauroyl peroxides (BP and LP respectively) at room temperature in non-aqueous media by measuring the volume of released CO 2 . As the decomposition of BP and LP strongly depends on the solvent, the selection of “inert” one was based on preliminary results. Ethyl acetate and tetrachloromethane were used for BPD and LPD, respectively. Among factors that determined the catalytic performance of investigated samples their structural-sorption properties, surface chemistry and diffusion limitation have been considered. It was established that in spite of the high surface area of AC they show moderate catalytic activity comparing to CNT because of internal diffusion limitation. As a consequence, their activity is determined by the textural characteristic of carbon matrices. Catalytic performance of the CNT samples exceeds of AC in 2–20 times. Based on the calculated diffusion coefficients it was concluded that catalysis by CNT is carried out in the kinetic region on their accessible surface. Such catalytically active surface has a lot of N-containing functional groups as well as basic O-containing ones, therefore it shows better activity towards organic peroxides. Moreover, CNT’s surface is more hydrophobic that is promoting the reaction proceeding in non-aqueous media. The decomposition rate of steric BP is lower compared to the long chain of LP (in both cases of AC and CNT). Based on this finding, it could be predicted that mesoporous CNT with high content basic functionalities and good surface accessibility should be the excellent catalyst for diacyl peroxides decomposition in organic solvents.

Ethylene Carbonate-Based Electrolyte Decomposition and Solid-Electrolyte Interphase Formation on Ca Metal Anodes.

The formation of a solid-electrolyte interphase (SEI) in multivalent ion batteries, resulting from the decomposition of organic solvents at the anode interface, is a major bottleneck to their development as it prevents ionic diffusion and reversible stripping and plating. To gain insight into SEI formation in these systems, we investigate the decomposition of pure ethylene carbonate (EC) and an EC/Ca(ClO4)2 electrolyte on a Ca metal surface using density functional theory and ab initio molecular dynamics calculations. We first find that CaCO3, CaO, and Ca(OH)2 are all primary inorganic SEI components. We then investigate the reaction mechanisms of this decomposition, finding that although a fast two-electron reduction producing CO32- and C2H4 is thermodynamically and kinetically favorable, a reaction producing C2H4O22- and CO dominates when multiple EC molecules are considered. Finally, we find similar results upon the inclusion of Ca(ClO4)2 salt.

Microporous organic polymers based on hexaphenylbiadamantane: Synthesis, ultra-high stability and gas capture

Hexaphenylbiadamantane-based microporous organic polymers (MOPs) were successfully synthesized by Suzuki coupling under mild conditions. The obtained MOPs show high surface area (891m2g−1), ultra-high thermal (less than 40% mass loss at temperatures up to 1000°C) and chemical (no apparent decomposition in organic solvents for more than 7 days) stability, gas (H2, CO2, CH4) capture capabilities and vapor (benzene, hexane) adsorption. These combined abilities render the synthesized MOPs an attractive candidate as thermo-chemically stable adsorbents for practical use in gas storage and pollutant vapor adsorption.

Sn–O–C composite anode for Li secondary battery synthesized by an electrodeposition technique using organic carbonate electrolyte

The Sn–O–C composite anode for the Li secondary battery was synthesized by electrodeposition using an organic carbonate solvent. The composite of Sn with organic/inorganic compounds was prepared by the simultaneous reaction of the reduction of Sn2+ ions and electrolysis of the mixture of ethylene carbonate and propylene carbonate. The galvanostatic potential transients for the electrodeposition of the Sn–O–C composite indicate that multiple steps of reactions corresponding to the electrochemical reduction of the tin precursor and the decomposition of organic solvents are involved. The morphology, crystalline structure and chemical composition of the as-deposited Sn–O–C composite anode were characterized to elucidate the mechanism of the synthesis of the buffering matrix enduring volume expansion.The electrochemical behavior of the Sn–O–C composite anode was investigated by cyclic voltammetry and galvanostatical charge/discharged tests. The discharge capacity of 465 mAh (g of Sn)−1 was obtained at the 100th cycle showing 80% of the capacity retention after the 100th cycle. The discharge capacity was stable after the 50th cycle, where the phase transformation of the Sn element from Sn to Li0.4Sn at the discharged state was found.

SEI Layer Formation on Amorphous Si Thin Electrode during Precycling

The morphological and compositional changes of the solid electrolyte interphase (SEI) layer formed on the surface of Si thin electrodes during precycling were investigated. At the beginning of charging, the native layer ( and silanol) covering the surface of the Si thin electrode is readily destroyed and a new SEI layer is formed by the decomposition of both organic solvents and anions. At this stage, the interfacial resistance decreases to a minimum level. Thereafter, the interfacial resistance increases with charging due to the growth of an SEI layer, which is mainly originated from the decomposition of organic solvents. During the discharging process, an SEI layer was formed mainly by the decomposition of anions.

Ozone decomposition of hazardous chemical substance in organic solvents

Performance on the ozonation of hazardous chemicals in non-aqueous solutions, i.e. organic solvents, was studied in comparison with those in water. The specific conclusions obtained from this study are as follows: the rate of decomposition and the specific amount of decomposition per ozone consumption for orange II were higher in organic solvents like acetic acid, acetone, ter-butyl alcohol than in distilled water. The rates of trichloroethylene decomposition in organic solvents like acetic acid, acetone, and ethyl acetate were also higher than those in distilled water.

Synthesis of the monomeric antioxidant

The thermal decomposition oftrans-3,5-di-tert-butyl-4-hydroxy-cinnamic acid (BHC) in the solid state, in aqueous solution and in solutions in organic solvents was studied in order to develop a preparative method for the synthesis of the monomeric antioxidant 3,5-di-tertbutyl-4-hydroxystyrene (BHS). Thermal methods of analysis showed that, during the solidstate decomposition of BHC, its decarboxylation was accompanied by desalkylation and polymerization of the styrenic decomposition products. BHC decarboxylation is aqueous solution was also accompanied by polymerization. A kinetic study of BHC decomposition in organic solvents by 1 H-NMR spectrometry revealed that only the decomposition of BHC in aprotic dipolar solvents such as dimethylsulphoxide and dimethylformamide, at temperatures lower than 150°C, could be used as a preparative method for the synthesis of BHS. The decarboxylation of BHC took place by zero-order kinetics through a mechanism involving the ionization of BHC in the aprotic dipolar solvent. The reaction rate increased drastically with increasing solvent polarity and in the presence of trace amounts of BHC sodium salt. Both monomeric antioxidants, i.e. BHS and BHC, may be used to obtain polymer-bound antioxidants, e.g. by melt-grafting onto polyethylene.

179. Coumariloyl peroxide and its decomposition in organic solvents

179. Coumariloyl peroxide and its decomposition in organic solvents