ABSTRACT
Novel Schiff bases (SBs), namely, N1,N2-bis(2-(((E)-4-chlorobenzylidene)amino)ethyl)ethane-1,2-diamine (I), N1,N2-bis(2-(((E)-4-(dimethylamino)benzylidene)amino)ethyl)ethane-1,2-diamine (II), and N1,N'1-(ethane-1,2-diyl)bis(N2-((((Z)-4-dimethylamino)benzylidene) amino)methylethane-1,2-diamine) (III), were prepared and characterized by using elemental analysis, IR, and 1H NMR spectroscopy. For assessing carbon steel in diverse settings, with and without inhibitors at varying concentrations, electrochemical frequency modulation (EFM), electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (PP) techniques were employed. The results showed that the synthesized inhibitors effectively decreased the corrosion rate of carbon steel in acidic media and the inhibition efficiency reached up to 93% for compound III at a concentration of 250 ppm. In addition, all prepared compounds were successful as anticorrosion agents, and the inhibition mechanism followed chemisorption from the Langmuir isotherm. The data obtained from the theoretical analysis show that the efficiency of the prepared compounds was in the order III < II < I. Furthermore, quantum chemical calculations were performed to gain insight into the electronic structure of the compounds. The analysis of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) showed that compound III had the highest surface coverage due to its specific molecular structure and spacer. This observation agreed well with the Langmuir adsorption data.
ABSTRACT
The N1,N1,N3,N3-tetramethyl -N1,N3-diphenylpropane-1,3-diaminium dichloride ionic liquid (ILc) is an environmentally friendly catalyst for oxidative-extractive desulfurization of gas oil (sulfur content = 2400 ppm) in the presence of H2O2 as an oxidizing agent. The precise structure of the prepared IL was confirmed using FT-IR spectroscopy, and1H-NMR. The reaction temperature, IL ratios, H2O2 dosage, and reaction time were studied to assess their effects on the desulfurization efficiency. The thermodynamic parameters of the oxidation reaction were determined. A desulfurization efficiency of 84.7% was obtained after the extractive desulfurization process using acetonitrile as an organic solvent at a solvent to feed ratio of 1:1 (v/v). Furthermore, the prepared IL may be reused for at least six cycles without any significant change in its desulfurization performance or chemical structure, which confirms its high reusability.
ABSTRACT
Increased need for energy resources, as well as the urgent need to improve the air quality, have prompted further research to meet these challenges. Great efforts have been directed to reducing the impact of exhaust emissions. In literature, the effect of blending dimethyl carbonate (DMC) into fuel on engine performance and exhaust emissions has been investigated, and the obtained results were promising in decreasing exhaust emissions. In the present work, the effect of blending DMC into gasoline on the physicochemical properties was studied. Six fuel blends were prepared by blending base gasoline (G) with (0%, 2%, 4%, 6%, 8%, and 10%) of DMC. The volatility characteristics of the fuel blends were studied, such as the distillation curve, vapor pressure, and driveability index. The octane rating and the physicochemical properties of the fuel blends were also studied. The results of the study showed interesting findings that encourage refineries to be interested in this promising fuel additive. The results showed that the addition of DMC to gasoline has a very slight effect on the volatility of gasoline, unlike other oxygenated additives like short chain alcohols which cause a significant increase in the fuel volatility. The addition of DMC to gasoline causes an insignificant increase in the vapor pressure as the addition of 10% of DMC increases the vapor pressure by 2 kPa while it does not affect the values of T10, T50, and T90, which are the most important parameters of the distillation curve. The results also showed that its addition causes a remarkable increase in the octane rating. The RON has increased for the G-10DMC blend by about 5 points making the DMC a promising octane booster.
