Synthesis and application of SBA-15-supported CuO as an efficient catalyst for the oxidative C(sp2)-O coupling reaction

SBA-15-supported CuO was synthesized via wet impregnation of SBA-15 with copper (II) acetylacetonate followed by calcination in the static air. The BET surface area of the Cu-containing SBA-15 was approximately 600 m2/g, which significantly decreased in comparison with that of as-synthesized SBA-15 silica (1081 m2/g). The successful loading of copper with a 3.20 wt.% content was determined by ICP-OES analysis, consistent with theoretical composition. However, no Cu-based phases were detected on the PXRD results and TEM images for CuO/SBA-15 showed regular hexagonal meso channels remained, indicating that CuO species was well distributed in the SBA-15 framework via the applied synthetic procedure. Catalytic activity of SBA-15-supported CuO was investigated for the selective C(sp2)-O coupling reaction between salicylaldehyde and N, N-dimethylformamide (DMF) in the presence of di-tert butyl peroxide (DTBP) as an oxidant. Influence of the reaction conditions on the formation of desired product was studied including reaction time, temperature, reactant ratio, amount of catalyst and oxidant. The experimental results proved that the high activity of the prepared catalyst as the C(sp2)-O coupling product could be obtained in an excellent yield of 90% with only 3 mol% of SBA-15-supported CuO in the presence of 4 equivalents of DTBP at 120 °C in 2 hours.

Sodium and Potassium tert-Butyl Peroxide Hydrates: Crystal Structure and Properties

Sodium and potassium tert-butyl peroxide hydrates 2Na+·2C4H9$${\text{O}}_{2}^{ - }$$·7H2O (I) and 2K+· 2C4H9$${\text{O}}_{2}^{ - }$$·4H2O (II) were prepared. According to X-ray diffraction data (CIF files CCDC no. 2081025 (I) and no. 2081024 (II)), the compounds are coordination polymers in which alkali metal atoms have C.N.(Na) of 6 or C.N.(K) of 6 and 8. The crystal packings comprise layers with clearly defined hydrophobic surfaces consisting of hydrocarbon groups and hydrophilic inner areas including water molecules, alkali metal cations, and peroxy groups of the tert-butyl peroxide anions. Compounds were characterized by vibrational spectroscopy, 1H, 13C NMR spectroscopy, thermogravimetry, and differential scanning calorimetry.

Evaluating the outcomes of a single-cylinder CRDI engine operated by lemon peel oil under the influence of DTBP, rice husk nano additive and water injection

In the search for an alternative energy source with lesser pollution for transportation needs, bio-oil, a denser and viscous fuel that needs a transesterification process, have been widely considered for diesel engines. However, these problems are solved by using low viscous biofuel, but this improvement also significantly leads to increased NOx emission. Hence this present study investigates the usage of a low viscous biofuel in the CRDI engine with measures to reduce NOx emission through water injection technique. The low viscous bio-oil was used in this study along with an ignition enhancer (di-tert-butyl-peroxide), non-metallic nano additive (rice husk). They were tested in a constant speed, single-cylinder, diesel engine for various loads. Considering the brake thermal efficiency (BTE), 2% and 150 ppm were selected as the optimum value after testing five ratios (1%, 1.5%, 2%, 2.5% and 3%) of di tert butyl peroxide (DTBP) and four ratios (50, 100, 150 and 200 ppm) of rice husk (RH). The lemon peel oil (LPO) with the optimum additive ratio produced 30.69% BTE, which was 4.7% lesser than diesel fuel. A considerable decrease in fuel consumption and emissions except for nitrogen oxides (NOx) is recorded. NOx emission increased by 17.3% for the biofuel blend containing RH and DTBP. To control NOx emission, 2% of water was injected into the intake manifold with the fresh intake air. Two percent by vol. was finalised after experimenting four ratios (1%, 2%, 3% and 4%) of water addition. This 2% water reduces 11% of NOx emission and affects the other outputs, denoted with the 8.9% reduced BTE value compared with diesel fuel. Thus, the LPOC combination proved to operate well in the CRDI engine and produces lower NOx emissions than other LPO blends.

Preparation, Antioxidant Properties and Ability to Increase Intracellular NO of a New Pyridoxine Derivative B6NO

In the case of various pathologies, an imbalance between ROS generation and the endogenous AOS can be observed, which leads to excessive ROS accumulation, intensification of LPO processes, and oxidative stress. For the prevention of diseases associated with oxidative stress, drugs with antioxidant activity can be used. The cytotoxic, antioxidant, and NO-donor properties of the new hybrid compound B6NO (di(3-hydroxy-4,5-bis(hydroxymethyl)-2-methylpyridinium) salt of 2-(nitrooxy)butanedioic acid) were studied. It was determined that B6NO chelates iron ions by 94%, which indicates B6NO’s ability to block the Fenton reaction. The hybrid compound B6NO inhibits the process of initiated lipid peroxidation more effectively than pyridoxine. It was shown that B6NO exhibits antioxidant properties by decreasing ROS concentration in normal cells during the oxidative stress induction by tert-Butyl peroxide. At the same time, the B6NO antioxidant activity on tumor cells was significantly lower. B6NO significantly increases the intracellular nitrogen monoxide accumulation and showed low cytotoxicity for normal cells (IC50 > 4 mM). Thus, the results indicate a high potential of the B6NO as an antioxidant compound.

Prediction-Optimization of the Effects of Di-Tert Butyl Peroxide-Biodiesel Blends on Engine Performance and Emissions Using Multi-Objective Response Surface Methodology (MORSM)

Alternative fuels, such as biodiesel, can be used in place of fossil fuels, although they have a greater viscosity and a longer igniting delay. To compensate for these limitations, several additives are added to biodiesel. The cetane improver Di-Tert Butyl Peroxide (DTBP) was investigated as an additive in this work. DTBP was shown to influence the combustion and emission properties of waste cooking oil biodiesel-diesel blends. The multi-objective response surface technique (MORSM) with Box-Behnken design was used to decrease the number of trials to conserve precious resources such as human effort, time, and money. Theil's uncertainty for the model's predictive capabilities (Theil's U2) was less than 0.1189, demonstrating its robustness. Nash-Sutcliffe efficiency was excellent (0.9885 – 0.9995), with a mean absolute percentage error of less than 1.32%. The engine operating parameters that were optimized were 71.64% engine load, 4964 ppm DTBP additive, and 24.98-degree advance ignition timing. The MORSM-based proposed technique's reliability and robustness validate the usage of DTBP with biodiesel blends, model prediction, and optimization.

Copper/Di-tert-butyl Peroxide-Catalyzed Regioselective Hydroxyphosphorylation of 1,3-Enynes

The copper/di-tert-butyl peroxide-catalyzed regioselective hydroxyphosphorylation of 1,3-enynes is described. The advantages of the reported radical reactions are excellent functional group tolerance, the use of a catalytic amount of copper and di-tert-butyl peroxide ( t BuOO t Bu) as a radical initiator, and mild reaction conditions. The desired products are obtained in moderate to excellent yields after purification.