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Methanol
Published in Arumugam S. Ramadhas, Alternative Fuels for Transportation, 2016
Mustafa Canakci, Oguzhan Ilgen
Methanol can be used to make methyl tertiary-butyl ether (MTBE), which is blended with gasoline to enhance octane and create cleaner burning fuel. But MTBE production and use also has disadvantages because it contaminates groundwater (http://www.ceert.org 2009). The closely related derivative of methanol, dimethyl ether (DME) is a highly desirable alternative fuel. It is generally produced by dehydration of methanol. Also it has been known as an ultra-clean fuel, which can be used in diesel engines, households, power generation, and for other purposes. Due to the huge market potential, the research on DME synthesis and its utilization have been attracting more and more interest. DME is also produced mainly from synthesis gas through methanol synthesis and methanol dehydration known as the two-step process (Jia, Tan, and Han 2006). Because of its high cetane number and favorable combustion properties, it is a particularly effective fuel for diesel engines. DME blends well with gasoline or diesel to be used as fuels in internal combustion engines or electricity generators. DME is also a potential substitute for liquefied natural gas (LNG) and LPG for heating homes and in industrial uses (Olah and Prakash 2006). Another methanol derivative is dimethyl carbonate (DMC), which can be obtained by converting methanol with phosgene or by oxidative carbonylation of the methanol. DMC has a high cetane rating, and can be blended into diesel fuel in a concentration up to 10%, reducing fuel viscosity and improving emissions (Olah and Prakash 2006).
Reactivity trends for mechanochemical reductive coupling of aryl iodides
Published in Green Chemistry Letters and Reviews, 2023
Courtney Carson, Joshua Hassing, Trinity Olguin, Karl P. Peterson, Rebecca A. Haley
These results present a better understanding of the extent to which solvent is necessary for mechanochemical reductive coupling reactions. However, we were interested to determine if a greener LAG solvent could replace DMF in the reaction. Dimethyl carbonate (DMC) is a greener chemical and solvent that has garnered more interest as a replacement for less desirable solvents (19). DMF is known to be reprotoxic and is considered undesirable by most, if not all solvent-selection guides (20). In contrast, DMC is nontoxic, biodegrades readily, and is noncorrosive to metal, making it a better choice in terms of safety and biodegradability (21). We repeated the experiments for 3a and 5a with DMC instead of DMF (Figure 3). Complete conversion of 3a to 3b was observed after only 0.1 equivalents of DMC were added to the reaction conditions. The results for the reaction of 5a were slightly less dramatic, with 0.1 equivalents of DMC leading to 68% conversion. However, 1 equivalent of DMC was effective in converting 91% of 5a to 5b and still follows LAG quantities.
Effect of dimethyl carbonate on the micromorphology and structure of combustion particles from diesel engines
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2020
Mingdi Li, Yang Zhao, Jia Fang, Shuyang Zhao, Guangju Xu, Zhong Wang
The use of oxygenated fuels in diesel engines is an effective way to achieve fuel diversification and clean combustion (Bergthorson and Thomson 2015; Guan et al. 2017). Studies by international and domestic researchers have shown that the effect of oxygenated fuels on particles is mainly reflected in the formation of important intermediate combustion products and the microstructure of PM. Tan, Y R investigated the sooting tendency of PODEn/diesel blends. The performance of PODEn with different chain length (addition of -CH2O-units) was benchmarked against other oxygenated soot suppression additives, including esters (methyl butyrate), carbonates (dimethyl carbonate DMC) and alcohols (n-butanol). Soot reduction induced by the dilution of the aromatic fraction in the diesel fuel was found to have the biggest impact, followed by soot reduction by decreasing the hydrocarbon chain length and to a lesser extent increasing the oxygen content (Tan et al. 2018). Zhang, Z H et al studied the effects of oxygenated fuel blends on carbonaceous particulate composition and particle size distributions from a stationary diesel engine. The results showed that diglyme (DGM), palm oil methylester (PME), dimethyl carbonate (DMC), diethyl adipate (DEA) and butanol (Bu) with ultralow sulfur diesel (ULSD), all five oxygenates were found to be effective at reducing particulate mass emissions. The reduction in both particle mass and number emissions was affected not only by the oxygen content but also by the chemical structure and thermophysical properties of oxygenates (Zhang and Balasubramanian 2014). The study by Paladpokkrong, C et al showed that oxygenated fuel represents an attractive alternative as an additive for reducing soot emissions. Dimethyl carbonate (DMC) is an oxygenated compound which is a good option to reduce soot due to the higher reactivity (Paladpokkrong et al. 2018). The studies by He et al. (2017), Guan et al. (2017) and Elvati, Dillstrom, and Violi (2016) have shown that when oxygenated fuels are used in diesel engines, the external bonding structure of particles changes in the early oxidation stage, which enhances the oxidation of the particles by oxygen-containing groups and changes the arrangement of the microcrystalline carbon layers of the particles, thereby affecting the microstructure of the particles finally formed. The study by Tsolakis et al at the University of Birmingham (Tsolakis 2006) shows that the physicochemical properties, oxygen content, and oxygen-containing functional groups of oxygenated fuel are critical factors affecting the local concentration of active oxygen during the combustion process, and the active oxygenated intermediates generated from combustion can suppress particle nucleation and promote particle oxidation.