Polyoxymethylene dimethyl ether

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Polyoxymethylene dimethyl ether
Polyoxymethylene dimethyl ether
other names

OME

Brief description Fuel or fuel additive for compression-ignition piston engines
origin

synthetic, CO 2 -favorable when using residual biomass

properties
Physical state liquid
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Polyoxymethylene dimethyl ethers (OME) are oxygen-containing oligomers. The oligomers protected as methyl ether at the chain ends have the chemical structure H 3 C-O- (CH 2 O) n -CH 3 with n ≥ 2. The name of the analogous chemical compound with the chain length n = 1 is methylal . OME are colorless, flammable liquids whose physical properties depend on the chain length n . A long-chain variant of these oligomers is the plastic polyoxymethylene .

use

OME (with n between 3 and 5) can be used as diesel fuel components or as a complete alternative to diesel fuel. They bring about a reduction in soot emissions during the combustion process. OMEs can also be used as physical solvents for CO 2 absorption from natural gases . The production costs for making OME are comparable to making diesel fuel.

Synthesis routes

OME can be produced using synthesis gas on various synthesis routes. In a first process step, synthesis gas has to be converted into methanol . This usually also produces dimethyl ether as a by-product. In a second step, methanol is oxidized to formaldehyde .

The state of the art is the OME synthesis from the anhydrous intermediates methylal and trioxane . Methylal is synthesized from methanol and formaldehyde. Trioxane is synthesized from formaldehyde in aqueous solution and then purified to an anhydrous product. It is also possible to use dimethyl ether as the starting material instead of methylal. The reaction mixture is worked up by distillation.

OME can also be synthesized directly from formaldehyde and methanol in an aqueous solution without intermediate steps. The process is complex as the presence of water leads to numerous azeotropes .

OME can also be made from renewable raw materials.

Individual evidence

  1. ↑ Björn Lumpp, Dieter Rothe, Christian Pastötter, Reinhard Lämmermann, Eberhard Jacob: OXYMETHYLENETHER AS DIESEL FUEL ADDITIVES OF THE FUTURE . In: MTZ - Motortechnische Zeitschrift. 72, 2011, p. 198, doi : 10.1365 / s35146-011-0049-8 .
  2. ^ D. Moulton, David Naegeli: Diesel fuel having improved qualities and method of forming , US Patent 5746785.
  3. ↑ G.-D. Tebben, H. Schelling, E. Ströfer, R. Pinkos et al .: Biodiesel fuel mixture containing polyoxymethylene dialkyethers , European Patent 1899438B1.
  4. ↑ M. Härtl, P. Seidenspinner, E. Jacob, G. Wachtmeister: Oxygenate screening on a heavy-duty diesel engine and emission characteristics of highly oxygenated oxymethylene ether fuel OME1 , Fuel 153 (2015) 328-335. doi : 10.1016 / j.fuel.2015.03.012 .
  5. ↑ L. Lautenschütz, D. Oestreich, P. Seidenspinner, U. Arnold, E. Dinjus, J. Sauer: Physico-chemical properties and fuel characteristics of oxymethylene dialkyl ethers , Fuel 173 (2016) 129-137. doi : 10.1016 / j.fuel.2016.01.060 .
  6. ↑ B. Lumpp, D. Rothe, C. Pastötter, R. Lämmermann, E. Jacob: Oxymethylene Ethers As Diesel Fuel Additives Of The Future , MTZ 72 (2011) 34-38. doi : 10.1365 / s38313-011-0027-z .
  7. ↑ Special: International Motor Congress 2015 With Commercial Vehicle Engines - Special . Springer-Verlag, 2015, ISBN 978-3-658-08861-3 , pp. 267 ( limited preview in Google Book search).
  8. Jump up ↑ J. Burger, V. Papaioannou, S. Gopinath, G. Jackson, A. Galindo, CS Adjiman: A hierarchical method to integrated solvent and process design of physical CO 2 absorption using the SAFT-γ Mie approach , AIChE J. 61 (2015) 3249-3269. doi : 10.1002 / aic.14838 .
  9. ^ N. Schmitz, J. Burger, E. Ströfer, H. Hasse: From methanol to the oxygenated diesel fuel poly (oxymethylene) dimethyl ether: An assessment of the production costs , Fuel 185 (2017) 67-72. doi : 10.1016 / j.fuel.2016.07.085 .
  10. ↑ Ludger Lautenschütz, Dorian Oestreich, Philipp Haltort, Ulrich Arnold, Eckhard Dinjus: Efficient synthesis of oxymethylene dimethyl ethers (OME) from dimethoxymethane and trioxane over zeolites . In: Fuel Processing Technology . tape 165 , p. 27–33 , doi : 10.1016 / j.fuproc.2017.05.005 ( elsevier.com [accessed April 2, 2018]).
  11. ↑ H. Schelling, E. Ströfer, R. Pinkos, A. Haunert et al .: Method for producing polyoxymethylene dimethyl ethers , Patent WO 2006 / 045506A1
  12. ↑ J. Burger, H. Hasse: Multi-objective optimization using reduced models in conceptual design of a fuel additive production process , Chem. Eng. Sci. 99 (2013) 118-126.
  13. ↑ J. Burger, M. Siegert, E. Ströfer, H. Hasse: Poly (oxymethylene) dimethyl ethers as components of tailored diesel fuel: Properties, synthesis and purification concepts , Fuel 89 (2010) 3315-3319.
  14. ↑ J. Burger, E. Ströfer, H. Hasse: Chemical Equilibrium and Reaction Kinetics of the Heterogeneously Catalyzed Formation of Poly (oxymethylene) Dimethyl Ethers from Methylal and Trioxane , Ind. Eng. Chem. Res. 51 (2012) 12751-12761.
  15. ↑ J. Burger, E. Ströfer, H. Hasse: Production process for diesel fuel components poly (oxymethylene) dimethyl ethers from methane-based products by hierarchical optimization with varying model depth , Chem. Eng. Res. Des. 91 (2013) 2648-2662. doi : 10.1016 / j.cherd.2013.05.023
  16. ↑ Ludger Lautenschütz: New findings in the synthesis optimization of oligomeric oxymethylene ethers from dimethoxymethane and trioxane . Ed .: University of Heidelberg, www.ub.uni-heidelberg.de/archiv/19210. Heidelberg 2015.
  17. ↑ J.-O. Drunsel, Development of Processes for the Production of Methylal and Ethylal : Dissertation, Kaiserslautern, 2012.
  18. ^ T. Grützner, H. Hasse, N. Lang, M. Siegert, E. Ströfer: Development of a new industrial process for trioxane production , Chem. Eng. Sci. 62 (2007) 5613-5620.
  19. ↑ Philipp Haltort, Kathrin Hackbarth, Dorian Oestreich, Ludger Lautenschütz, Ulrich Arnold: Heterogeneously catalyzed synthesis of oxymethylene dimethyl ethers (OME) from dimethyl ether and trioxane . In: Catalysis Communications . tape 109 , p. 80–84 , doi : 10.1016 / j.catcom.2018.02.013 ( elsevier.com [accessed April 2, 2018]).
  20. ↑ N. Schmitz, F. Homberg, J. Berje, J. Burger, H. Hasse: Chemical equilibrium of the synthesis of poly (oxymethylene) dimethyl ethers from formaldehyde and methanol in aqueous Solutions , Ind. Eng. Chem. Res. 54 (2015) 6409-6417.
  21. ↑ N. Schmitz, J. Burger, H. Hasse: Reaction Kinetics of the Formation of Poly (oxymethylene) Dimethyl Ethers from Formaldehyde and Methanol in Aqueous Solutions , Ind. Eng. Chem. Res. 54 (2015) 12553-12560.
  22. ↑ Dorian Oestreich, Ludger Lautenschütz, Ulrich Arnold, Jörg Sauer: Reaction kinetics and equilibrium parameters for the production of oxymethylene dimethyl ethers (OME) from methanol and formaldehyde . In: Chemical Engineering Science . tape 163 , 2017, p. 92-104 , doi : 10.1016 / j.ces.2016.12.037 ( elsevier.com ).
  23. ↑ Dorian Oestreich: Process development for the production of oxymethylene ethers (OME) from methanol and formaldehyde . KIT Scientific Publishing, Karlsruhe 2017, ISBN 978-3-7315-0669-0 , doi : 10.5445 / ksp / 1000069417 ( kit.edu ).
  24. ↑ Technical University of Kaiserslautern: Oxymethylene ether (OME): An alternative to expensive exhaust gas aftertreatment in diesel engines , accessed on April 27, 2016.