F Dimethyl ether

Dimethyl sulfate, reaction with di-methylformamide, 47, 52 Dimethyl sulfoxide, in synthesis of phenyl f-butyl ether, 45, 89 potassium salt, preparation, 48, 109, 110... 

Note that for acetic acid there is a hydrogen attached to an oxygen atom (a prerequisite for H bonding) but that for dimethyl ether there is no H atom connected to an F, O, or N atom. 

Depending on the reason for converting the produced gas from biomass gasification into synthesis gas, for applications requiring different H2/CO ratios, the reformed gas may be ducted to the water-gas shift (WGS, Reaction 4) and preferential oxidation (PROX, Reaction 5) unit to obtain the H2 purity required for fuel cells, or directly to applications requiring a H2/CO ratio close to 2, i.e., the production of dimethyl ether (DME), methanol, Fischer-Tropsch (F-T) Diesel (Reaction 6) (Fig. 7.6). 

Wu, H.-F. Lin, Y.-P. Determination of the Sensitivity of an External Source Ion Trap Tandem Mass Spectrometer Using Dimethyl Ether Chemical Ionization. J. Mass Spectrom. 1999,54,1283-1285. 

The reaction is run at about 350°F and 200 psi and yields about 99% acetic acid. That is, about 99% of the methanol that gets converted ends up as acetic acid. By-products include only small amounts of dimethyl ether and methyl acetate. 

Chen, Y., Zhou, H., Zhu, J., Zhang, Q., Wang, Y., Wang, D., and Wei, F. (2008) Direct synthesis of a fluidizable SAPO-34 catalyst for a fluidized dimethyl ether to olefins process. 

Song, W., Marcus, D.M., Fu, H., Ehresmann, J.O., and Haw, ).F. (2002) An ofr-smdied reaction that may have never been direct catalytic conversion of methanol or dimethyl ether to hydrocarbons on the solid acids HZSM-5 or HSAPO-34./. Am. Chem. Soc., 124, 3844-3845. 

Fig. 1. Expansions of an activated charcoal rod produced by the adsorption of ethyl chloride (O) at 10 C. and dimethyl ether (-f) at 6.5 C. (64).

Electrolytic reduction, apparatus, 52, 23 Enol acetates, acylation of, 52,1 Enol esters, preparation, 52, 39 Epichlorohydrin, with boron trifluoride diethyl therate and dimethyl ether to give trimethyloxonium tetra-fluoroborate, 51,142 ESTERIFICATION OF HINDERED ALCOHOLS f-BUTYL p-TOLUATE,... 

For the comparison of hydroperoxides with methyl ethers (equation 2), we find there is enthalpy of formation data only for dimethyl ether, isopropyl methyl ether and t-butyl methyl ether (again ignoring the ethyl and propyl hydroperoxides). The enthalpies of formal reaction 2 for R = Me, i-Pr and f-Bu (two gas phase enthalpies of formation for f-BuOOH) are —53.1, —54.9 and —37.6 or —48.6 kJmoU, respectively, in the gas phase. In the liquid phase, the enthalpies of reaction are —7.4, —35 (from the estimated enthalpy of formation of isopropyl hydroperoxide) and —20.0 kJmoU, respectively. Because the enthalpy of formation deviations from linearity for dimethyl ether and methyl hydroperoxide might not be identical, the reaction enthalpy might not be consistent with those... 

As was the case for the alkyl hydroperoxides in reaction 4, the enthalpies of the oxy-gen/hydrocarbon double exchange reaction 8 for dialkyl peroxides are different depending on the classification of the carbon bonded to oxygen. For R = Me, Et and f-Bu, the liquid phase values are —4, 24.6 and 52.7 kJmoR, respectively, and the gas phase values are 0.1, 25.7 and 56.5 kJmoR, respectively. For the formal deoxygenation reaction 9, the enthalpies of reaction are virtually the same for dimethyl and diethyl peroxide in the gas phase, —58.5 0.6 kJ moR. This value is the same as the enthalpy of reaction of diethyl peroxide in the liquid phase, —56.0 kJ moR (there is no directly determined liquid phase enthalpy of formation of dimethyl ether). Because of steric strain in the di-ferf-butyl ether, the enthalpy of reaction is much less negative, but still exothermic, —17.7 kJmol (Iq) and —19.6 kJmol (g). 

Cold weather starting for ethanol fuels is poor unless blended with gasoline or some other starting fluid such as dimethyl ether or isopentane. The minimum starting temperature for neat ethanol fuel is about 60°F (15.6°F). In E95, E85, and E10 blends, the starting problems are minimized. 

The simplest of the ethers would be ether that has the simplest hydrocarbon backbones attached those backbones are the radicals of the simplest hydrocarbon, methane. Therefore, the simplest of the ethers is dimethyl ether, whose formula is CH3OCH3. Dimethyl is used because there are two methyl radicals, and "di-" is the prefix for two. This compound could also be called methyl methyl ether, or just plain methyl ether, but it is better known as dimethyl ether. It is an easily liquified gas that is extremely flammable, has a relatively low ignition temperature of 66°F, and is used as a solvent, a refrigerant, a propellant for sprays, and a polymerization stabilizer. 

Ib methyl fluoride two electrons with opposed spins are concentrated along the C—F bond. The fluorine atom is, in consequence of correlation, presumably not cylindrically symmetrical about the bond direction, but somewhat hexafoliate. In water and dimethyl ether the two unshared electron pairs of the oxygen atom, despite the effect of correlation, are directed toward two corners of the tetrahedron that has its other two corners determined by the two bonds. 

Sulfuryl Azide Fluoride. N3S02.F mw 125.09 N 33.60%- liq. Prepn is by reacting Li azide with sulfuryl fluoride in a mixt of dimethylformamide and dimethyl ether at 25° for 19 hrs with stirring. Excess volatiles are then removed at —66° under vac. The reaction flask is then warmed to RT and the azide prod is distld off to a cooled receiver. The authors (Ref 3) report that the azide is believed to be an expl Refs 1) Gmelin, Syst Nr 9, Tell B, Lieferung B (1963), 1562 ff 2) W. Trauble A. Vocker-odt, Uber Hydrazine und Azidosulfonsaure , Ber 47, 938 (1914) CA 8, 2130 (1914)... 

The rate constants for the reactions between OH and a range of ethers and hydroxy ethers have been reported at 298 K233 as well as those for reactions between dimethyl ether and methyl f-butyl ether over the range 295-750 K.234 Data from the former study show deviations from simple structure-activity relationships which were postulated to arise due to H-bonding in the reaction transition states.233 The atmospheric lifetime of methyl ethyl ether has been determined to be approximately 2 days.235 Theoretical studies on the H-abstraction from propan-2-ol (a model for deoxyribose) by OH have been reported using ab initio methods (MP2/6-31G ).236 The temperature dependence (233-272 K) of the rate coefficients for the reaction of OH with methyl, ethyl, n-propyl, n-butyl, and f-butyl formate has been measured and structure-activity... 

Olah et al.603 have observed the formation of cation 309 (protonated fluorometha-nol) upon treatment of formaldehyde in HF-SbF5 [Eq. (3.81)]. When Minkwitz et al.605 attempted to isolate salts of the ion, however, the hydroxymethyl(methylidene) oxonium ion 310 was obtained [Eq. (3.81)]. Crystal structure analysis of the hexafluoroarsenate salt shows that cations and anions are connected by short H -F distances, forming a three-dimensional network. The bond lengths of the C-0=C fragment (1.226 and 1.470 A) are longer than those in formaldehyde (1.208 A) and dimethyl ether (1.410 A). The C—O—C bond angle is 121.2°. 

Schoneich C, Dillinger U, von Bruchhausen F, Asmus K-D (1992) Oxidation of polyunsaturated fatty adds and lipids through thiyl and sulfonyl radicals reaction kinetics, and influence of oxygen and structure of thiyl radicals. Arch Biochem Biophys 292 456-467 Schuchmann H-P, von Sonntag C (1981) Photolysis at 185 nm of dimethyl ether in agueous solution Involvement of the hydroxymethyl radical. J Photochem 16 289-295 Schuchmann H-P, von Sonntag C (1997) Fleteroatom peroxyl radicals. In Alfassi ZB (ed) Peroxyl radicals. Wiley, Chichester, pp 439-455... 

Oxybis(Av V-dimethylacetamidetriphenylstibonium) perchlorate, 3905 [l,l -Oxybis[ethane]]tris(trimethyl silyl)aluminium, see Tris(trimethylsilyl)aluminium etherate, 3614 f l,l -Oxybisethene, see Divinyl ether, 1516 2,2 -Oxybis(ethyl nitrate), 1594 f Oxybismethane, see Dimethyl ether, 0915... 

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