919-94-8Relevant academic research and scientific papers
METHOD OF PRODUCING TERTIARY AMYL ETHYL ETHER
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Page/Page column 6-7, (2009/04/24)
A process for the production of tertiary ethers, including: feeding a hydrocarbon stream comprising isoolefins and propionitrile to a distillation column reactor system containing at least one etherification reaction zone; feeding a C2 to C6 monoalcohol or mixture thereof to the distillation column reactor; concurrently in the distillation column reactor system: reacting a portion of the isoolefins with a portion of the alcohols to form a tertiary ether; and separating the tertiary ether from unreacted isoolefins; withdrawing the tertiary ether and propionitrile from the distillation column reactor system as a bottoms; withdrawing the unreacted isoolefins from the distillation column reactor system as an overheads; and operating the distillation column reactor system such that the etherification reaction zone is substantially free of propionitrile.
Thermochemistry of branched ethers: Experimental study of chemical equilibrium in the reacting system of tert-amyl alkyl ether synthesis
Verevkin, Sergey P.
, p. 576 - 581 (2007/10/03)
The chemical equilibrium of the reactive systems (alkanol + methylbutenes ? alkyl tert-amyl ether) with the following alkyl substituents: ethyl, propyl, butyl, iso-propyl, sec-butyl, and cyclohexyl, were studied in the liquid phase. Reactions were investigated in the screwed vials in the temperature range (298 to 393) K, and a cation exchanger Amberlist 15 was used as heterogeneous catalyst. Enthalpies of reactions ΔrH m° of teri-amyl alkyl ethers synthesis in the liquid phase were obtained from the temperature dependence of the equilibrium constants and used to derive standard enthalpies of formation, ΔfH m°(1), of tert-amyl alkyl ethers. For the sake of comparison, these enthalpies of formation have been calculated using improved Benson's increments. Calculated values are in close agreement with those from thermochemical measurements.
Enthalpies of formation of 2-methyl-2-ethoxypropane and 2-ethyl-2-ethoxypropane from equilibrium measurements
Sharanov, K. G.,Rozhnov, A. M.,Korol'kov, A. V.,Karaseva, S. Y.,Miroshnichenko, E. A.,Korchatova, L. I.
, p. 751 - 754 (2007/10/02)
The equilibria for the synthesis of C2H5OC(CH3)3 (A) and C2H5OC(CH3)2(C2H5) (B) from C2H5OH (C) and CH2:C(CH3)2 (D) or CH3CH:C(CH3)2 (E) in the liquid phase were investigated at temperatures from 313 K to 412 K.On the basis of experimental equilibrium constants found for n(C)/n(D) or n(C)/n(E) >/= 4, the following values were obtained for ΔrH0m/(kJ * mol-1) and ΔrS0m/(J * K-1 * mol-1): (C + D = A), -(35.45 +/- 1.94) and -(82.37 +/- 5.99); (C + A = B), -(34.13 +/- 0.81) and -(87.82 +/- 2.18).The following values of ΔfH0m(298.15 K)/(kJ * mol-1) have been derived: C2H5OC(CH3)3(l), -(350.8 +/- 2.6); C2H5OC(CH3)2(C2H5)(l), -(379.8 +/- 1.4).
Reaction Equilibria in the Synthesis of 2-Methoxy-2-methylbutane and 2-Ethoxy-2-methylbutane in the Liquid Phase
Rihko, Liisa K.,Linnekoski, Juha A.,Krause, A. Outi I.
, p. 700 - 704 (2007/10/02)
Equilibrium constants for the liquid-phase synthesis of 2-methoxy-2-methylbutane (TAME) and 2-ethoxy-2-methylbutane (TAEE) were measured in the temperature range 323-363 K.The equilibria were studied using the alcohol/alkene mixture in various mole ratios and the respective ether as a reagent in a batch reactor.A commercial cation exchange resin (Amberlyst 16) was used as the catalyst.The system was strongly nonideal, and the UNIQUAC estimation method was used in the calculation of the liquid-phase activity coefficients.The experimental equilibrium constants are given as a function of temperature.At 333 K the equilibrium constants Ka for the synthesis of TAME were 39.6+/-2.5 from methanol and 2-methyl-1-butene (2M1B) and 4.1+/-0.3 from 2-methyl-2-butene (2M2B).The equilibrium constants for the synthesis of TAEE were 17.4+/-1.1 from ethanol and 2M1B and 1.7+/-0.1 from 2M2B.The experimental ΔrH values for the liquid-phase synthesis of TAME were -33.6+/-5.1 kJ*mol-1 (2M1B) and -26.8+/-2.3 kJ*mol-1 (2M2B), and those for the synthesis of TAEE were -35.2+/-5.8 kJ*mol-1 (2M1B) and -27.3+/-6.7 kJ*mol-1 (2M2B).The results were compared with the literature values.
The Mechanism of Ethylene Elimination from the Oxonium Ions CH3CH2CH=O+CH2CH3 and (CH3)2C=O+CH2CH3
Bowen, Richard D.,Derrick, Peter J.
, p. 1033 - 1039 (2007/10/02)
The reactions of the metastable oxonium ions CH3CH2CH=O+CH2CH3 and (CH3)2C=O+CH2CH3 are reported and discussed.Various mechanisms for ethylene elimination, which is the principal dissociation route for these ions, are considered.It is shown by means of 2H-labelling experiments and analysis of collision-induced dissociation spectra that routes involving ion-neutral complexes pre-empt 'conventional' mechanisms for these processes.In contrast, the behaviour of the lower homologues CH3CH2CH=OR+ and (CH3)2C=OR+ (R = H, CH3) is consistent with the operation of 'conventional' mechanisms for ethylene expulsion.This contrast is interpreted in energetic terms.The significance of these results for the chemistry of homologous and analogous 'onium' ions containing a Z+-R function (Z = O, S, NH, NCH3; R= CnH2n+1, n 2) is explained.
IODINE MEDIATED SYNTHESIS OF ALKYL TERTIO-ALKYL ETHERS
Jenner G.
, p. 2445 - 2448 (2007/10/02)
Mixed alkyl t-alkyl ethers have been prepared by the selective coupling of the alcohol precursors.Dehydration was promoted by iodine under hydrogen pressure at 100 deg C.
Solvomercuration-Demercuration. 12. The Solvomercuration-Demercuration of Olefins in Alcohol Solvents with Mercuric Trifluoroacetate--An Ether Synthesis of Wide Generality
Brown, Herbert C.,Kurek, Joseph T.,Rei, Min-Hon,Thompson, Kerry L.
, p. 1171 - 1174 (2007/10/02)
Studies on the solvomercuration-demercuration (SM-DM) of olefins in methyl, ethyl, isopropyl, and tert-butyl alcohols with mercuric trifluoroacetate have been extended. 1-Dodecene undergoes the SM-DM sequence with typical results for a monosubstituted olefin.Cyclopentene similarly exhibited behavior characteristic of a 1,2-disubstituted olefin in methanol, ethanol, and 2-propanol, giving high yields, >90percent of the corresponding ethers.However, in tert-butyl alcohol, the yields of ether were lower than normal and decreased somewhat with time. 2-Methyl-1-butene gives >90percent yields of the Markovnikov methyl ether.On the other hand, the yields of ethyl, isopropyl, and tert-butyl ethers are lower and decrease with time.Major improvements in yields, however, are possible by lowering the reaction temperature from room temperature to 0 deg C.Cyclooctene, surprisingly, behaves more like a tri-, tetra-, or isosubstituted olefin than a 1,2-disubstituted olefin.The yields of cyclooctyl methyl ether are >90percent and do not decrease with time.However, yields of the ethyl, isopropyl, and tert-butyl ethers are lower and drop with time.Again, lowering the reaction temperature from room temperature to 0 deg C markedly improves the yields of the cyclooctyl ethers.These results, coupled with those of a previous study, clearly reveal the exceptional superiority of mercuric trifluoroacetate for the SM-DM of olefins in alcohol solvents.
Solvomercuration-Demercuration. 11. Alkoxymercuration-Demercuration of Representative Alkenes in Alcohol Solvents with the Mercuric Salts Acetate, Trifluoroacetate, Nitrate, and Methanesulfonate
Brown, Herbert C.,Kurek, Joseph T.,Rei, Min-Hon,Thompson, Kerry L.
, p. 2551 - 2557 (2007/10/02)
The alkoxymercuration-demercuration of seven representative olefins with the mercuric salts acetate, trifluoroacetate, nitrate, and methanesulfonate, in methyl, ethyl, isopropyl, and tert-butyl alcohols was examined.Mercuric acetate was effective only in methanol and ethanol.On the other hand, mercuric trifluoroacetate was effective in all four solvents, giving in most cases high yields of the corresponding ethers.Both mercuric nitrate and mercuric methanesulfonate were effective in methanol, ethanol, and 2-propanol.However, in several cases poor selectivity for the ether was observed, as evidenced by the formation of significant amounts of side products.Both electronic and steric effects are important factors in the reaction.Moreover, the structure of the olefin has a pronounced effect, both on the types of oxymercurials formed and on their stability to the reaction conditions.
Catalysis by Iodine in the Solvolysis of Tertiary Alkyl Halides
Cox, Brian G.,Maskill, H.
, p. 1901 - 1906 (2007/10/02)
Solvolysis of t-butyl and t-amyl iodides in aqueous ethanol and aqueous hexafluoropropan-2-ol is catalysed by iodine.The same effect, but to a smaller extent, is also found for t-butyl bromide in aqueous ethanol; the strongest catalysis by iodine was found for the aqueous ethanolysis of 1-adamantyl iodide.The catalytic constants for aqueous ethanolysis of t-butyl iodide decrease less steeply than the rate constants of the uncatalysed reactions as the proportion of ethanol in the medium is increased.The results are accomodated by a mechanism involving pre-association of iodine with the alkyl halide superimposed upon a general mechanism for solvolysis the rate-determining step of which may be ionization, ion-pair separation, or reaction of reversibly formed intimate ion-pairs with the solvent according to the nature of the alkyl halide and the solvolytic medium.
Preparation and recovery of ethers
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, (2008/06/13)
Methyl t-butyl ether may be recovered from etherification reaction effluent by extractive distillation in the presence of n-butanol.
