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Oligomeric oxymethylene dimethyl ethers (OMEs) of the type CH 3 O-(CH 2 O) n -CH 3 are promising diesel fuels with an enormous potential for the reduction of soot and NO x emissions. Oligomers with n = 3–5 are particularly advantageous, since their physicochemical and combustion properties are similar to conventional diesel. OMEs can be produced from methanol and formaldehyde but a series of byproducts, especially hemiformals, glycols, water and minor amounts of cyclic ethers, are also formed. These need to be separated from the product mixtures, which affects efficiency of this synthesis pathway. To isolate the desired OMEs, a one-step synthesis/extraction procedure is described. It implies highly selective extraction of OMEs from aqueous reaction solutions employing hydrocarbons as extraction agents. If fuel-type hydrocarbons are used, the resulting OME-hydrocarbon blends can be directly used in fuel applications. The corresponding oxymethylene diethyl ethers (OMDEEs) have also been investigated. Compared to OMEs, OMDEEs exhibit an increased solubility in nonpolar media but, as a result, solubility of educts and byproducts also increases. OME blends with hydrogenated vegetable oil and diesel have been prepared containing 10% of OMEs. It could be shown that such blends meet current diesel standards to a large extent. [ABSTRACT FROM AUTHOR]

Oligomeric oxymethylene dimethyl ethers (OME n , CH 3 O(CH 2 O) n CH 3 ) bearing three to five CH 2 O units are promising diesel fuels for the reduction of soot and NO x emissions. Regarding the production of OMEs, a highly optimized process has not been realized yet. This work describes efficient synthesis of OMEs from dimethoxymethane (DMM) and trioxane in batch experiments at room temperature and atmospheric pressure. To ensure high reactivity and high OME yields, dry educts have been used and the influence of water has been investigated in detail. The ion exchange resin Amberlyst36 and zeolites have been employed as acidic catalysts. Zeolite BEA25 exhibited highest catalytic activity and the reaction could be completed within 12 min at 25 °C. Furthermore, the formation of byproducts could be fully eliminated. [ABSTRACT FROM AUTHOR]

Oligomeric oxymethylene dimethyl ethers (OME n, CH3(OCH2) nOCH3, n = 1 - 5) are promising diesel fuels for the reduction of harmful emissions. If OMEs are produced from dimethoxymethane and trioxane, the resulting OME mixtures usually contain residual trioxane which appears, after rectification, in the OME2 fraction. To circumvent this obstacle, substoichiometric amounts of trioxane have been employed in OME synthesis. Thus, OME2 samples with high purity could be prepared. Physicochemical and fuel data of high purity OME2 and higher OMEs have been determined to supplement previously reported data. [ABSTRACT FROM AUTHOR]

Oligomeric oxymethylene ethers (OMEs) are promising fuels for internal combustion engines with self-ignition. A tremendous reduction of soot, nitrogen oxide and hydrocarbon emissions can be realized by employing OMEs. This work describes the synthesis of OMEs from dimethyl ether (DME) and trioxane. Zeolite H-BEA 25 was found to be a suitable catalyst for this reaction and a study on reaction parameters (e.g. temperature, reactant feed ratio and reaction time) has been carried out. A maximum DME conversion of 13.9 wt% could be obtained and the maximum reactant-related product yield for OME 3–5 was 8.2 wt%. An OME formation mechanism is proposed which explains the observed product spectrum. [ABSTRACT FROM AUTHOR]

Abstract: Recent progress regarding the production of alternative liquid fuels is described with a focus on catalyst development. Fuels for spark ignition engines as well as diesel fuels are considered and their potentials regarding the reduction of harmful emissions are addressed. Two main strategies are described. The first implies production of synthesis gas from renewables or CO2 and subsequent synthesis of methanol or dimethyl ether. Both can be further converted to a series of valuable fuels, e.g., high‐quality gasoline or oxymethylene ethers. The second strategy comprises the production of ethanol and its conversion to gasoline. [ABSTRACT FROM AUTHOR]