513-35-9Relevant articles and documents
Tert-amyl methyl ether (TAME). Thermodynamic analysis of reaction equilibria in the liquid phase
Datta,Egleston,Syed
, p. 319 - 323 (2000)
Ethers obtained from C5 olefin streams provide a good mix of octane-enhancing and CO-reducing qualities. They are considered as a replacement for the more common isobutylene-derived fuel additives, e.g., MTBE. Data on the thermodynamic reaction equilibria for the synthesis of TAME, which is produced from the etherification reaction of 2-methyl-1-butylene and 2-methyl-2-butylene with methanol, were computed by studying TAME decomposition in a recirculating batch reactor at different temperatures with activity coefficients obtained using the UNIFAC method. A comparison of experimental data and theoretical predictions showed the possibility of erroneous values reported in the literature for the standard Gibbs free energy of TAME formation. Expressions for the thermodynamic equilibrium constants as a function of temperature were developed. A corrected value for the Gibbs free energy of formation for TAME was also provided.
Polysulfones: Catalysts for alkene isomerization
Markovic, Dean,Vogel, Pierre
, p. 2928 - 2930 (2004)
A radical intermediate is generated when methylidenecyclopentane (1) is isomerized by SO2 into 1-methylcyclopentene (3) through the formation of a polysulfone polymer (PS), which first abstracts a hydrogen atom from the alkene. The allyl radical intermediate 2 abstracts a hydrogen atom from another alkene molecule 1, to yield the isomerized alkene and regenerating the allyl radical. Polysulfones are organic catalysts.
Reactions of Propene and Cyclopropane Radical Cations with Neutral Ethylene
Vollmer, D. L.,Gross, M. L.
, p. 185 - 192 (1993)
The gas-phase reactions of propene and cyclopropane radical cations with neutral ethylene were investigated by using Fourier transform, chemical ionization and tandem mass spectrometries.Both reactions form covalent C5H10 adduct ions.The adduct ions are hypothesized to form initially as distonic radical cations that isomerize via a substituted cyclopropane intermediate and are detected as the most stable C5H10 isomer, the 2-methylbut-2-ene radical cation.The rate constant for each reaction is approximately 20percent of the theoretically collision rate, indicating that product ions are formed in one out of every five collisions of the C3H6 radical cationcs with neutral C2H4.
Novel synthesis of isoprene from 3-methylbutan-2-one using phosphate catalysts
Hutchings, Graham J.,Hudson, Ian D.,Bethell, Donald,Timms, Don G.
, p. 1489 - 1490 (1999)
AlPO4 and BPO4 catalyse the conversion of 3-methylbutan-2-one to isoprene in high yields via 2-methylbut-2-en-1-ol as an intermediate.
Vapor-liquid and chemical reaction equilibria in the synthesis of 2-methoxy-2-methylbutane (TAME)
Krause,Pavlov,Rihko-Struckmann,Linnekoski
, p. 1030 - 1035 (2000)
The isobaric VLE data were measured for three binary mixtures, i.e., methanol/TAME, methanol/2-methyl-2-butene, and methanol/2-methylbutane at 101.3 kPa. Based on the experimental results, the binary parameters were adjusted for the Wilson method of activity coefficient estimation. Using the Wilson method, the reaction equilibrium constants were recalculated for the liquid-phase synthesis of TAME. All systems exhibited a positive deviation from ideality with a minimum-boiling-point azeotrope. The azeotropic boiling points and the mole fractions of the binary systems obtained in the experiments agreed well with the values found in the literature. The non-ideality was well described with the Wilson method, and the equilibrium constants remained more invariable than those calculated earlier with the UNIQUAC method. Based on the experimental reaction equilibrium, a value of -109.6 kJ/mole was presented for the Gibbs energy of formation for TAME in the gas phase at 298 K.
Kinetics of the Thermal Isomerization of 1,1-Dimethylcyclopropane
Kalra, Bansi L.,Lewis, David K.
, p. 853 - 858 (2001)
Rate constants for the unimolecular thermal isomerization of gaseous 1,1-dimethylcyclopropane to isomeric methylbutenes have been measured, and Arrhenius parameters determined, over a wide temperature range, 683 - 1132 K, using a single-pulse shock tube and a static reactor. For the overall reaction, Ea = 61.8 +/- 0.4 kcal/mol, and log10(A, s-1) = 15.04 +/- 0.10. These values are in good agreement with previously reported values obtained over a much narrower temperature range. Rate constants for formation of the two major products, 2-methylbut-2-ene and 3-methylbut-1-ene, are given by Ea = 61.9 kcal/mol, logA = 14.80 and Ea = 61.1 kcal/mol, logA = 14.54, respectively. A comparison of the activation parameters for structural isomerizations of cyclopropane, methylcyclopropane, and 1,1-dimethylcyclopropane confirms a trend toward lower activation energy values as hydrogen atoms in cyclopropane are replaced by CH3 groups.
Enthalpy of combustion and enthalpy of vaporization of 2-ethyl-2-methoxypropane and thermodynamics of its gas-phase synthesis from (methanol + a 2-methylbutene)
Rozhnov, A. M.,Safronov, V. V.,Verevkin, S. P.,Sharonov, K. G.,Alenin, V. I.
, p. 629 - 635 (1991)
Equilibrium constants the gas-phase synthesis reaction of 2-ethyl-2-methoxypropane (EMOP) from methanol and a 2-methylbutene have been found at the temperatures: 373 K, 399 K, and 413 K.The molar enthalpy of combustion was determined calorimetrically. ΔvapHmdeg(298.15 K) = (35.3 +/- 1.5) kJ * mol-1 and ΔfHmdeg(298.15 K, g) = -(305.4 +/- 1.8) kJ * mol-1 were found for EMOP both on the basis of the results obtained in the present work and literature values.
Catalytic dehydrogenation of isopentane with iridium catalysts
Alt, Helmut G.,Boehmer, Ingrid K.
, p. 2619 - 2621 (2008)
(Graph Presented) Activation by adding PPh3: The catalytic dehydrogenation of isopentane to give isopentene and hydrogen with iridium catalysts ona silica gel support at 450°C proceeds with impressive conversion whenthe support is impregnated w
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 (1994)
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.
Hexaruthenium carbido carbonyl methyl cluster as catalyst precursor for hydrogenation of olefins. Syntheses and structures of unsaturated and saturated hexaruthenium hydrido clusters and
Chihara, T.,Yamazaki, H.
, p. 273 - 284 (1994)
Cluster (2) has been found to be catalytic active for the hydrogenation and isomerization of olefins at 60 deg C after an induction period.Reaction of 2 or with dihydrogen at 130 deg C gives an unsaturated hydrido cluster (6), which behaves as the catalyst at ambient temperature.The structure of 6 has a carbon-centered octahedral geometry of ruthenium atoms which is surrounded by fifteen carbonyl ligands, two terminal ones for each ruthenium atom and three bridging ones, and a bridging hydrido ligand.Treatment of 6 with carbon monoxide yields a saturated hydrido cluster (5), which is also prepared by protonation of 2.X-ray analysis of 5 shows the cluster anion is disordered between two sites in the ratio of 8 to 2.The major one contains a carbon centered octahedron of six ruthenium atoms with two terminal carbonyl ligands for each ruthenium atom, with four bridging carbonyl ligands, and a terminal hydrido ligand. Key words: Ruthenium; Carbide; Carbonyl; Cluster; Catalyst precursor
