- The low-temperature heat capacity and ideal gas thermodynamic properties of isobutyl tert-butyl ether
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The heat capacities of isobutyl tert-butyl ether in crystalline, liquid, supercooled liquid, and glassy states were measured by vacuum adiabatic calorimetry over the temperature range from (7.68 to 353.42) K. The purity of the substance, the glass-transition temperature, the triple point and fusion temperatures, and the enthalpy and entropy of fusion were determined. Based on the experimental data, the thermodynamic functions (absolute entropy and changes of the enthalpy and Gibbs free energy) were calculated for the solid and liquid states over the temperature range studied and for the ideal gas state at T = 298.15 K. The ideal gas heat capacity and other thermodynamic functions in wide temperature range were calculated by statistical thermodynamics method using molecular parameters determined from density-functional theory. Empirical correction for coupling of rotating groups was used to calculate the internal rotational contributions to thermodynamic functions. This correction was found by fitting to the calorimetric entropy values.
- Druzhinina,Dorofeeva,Varushchenko,Krasnykh
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Read Online
- METHOD FOR PRODUCING ASYMMETRIC ALKYL ETHER HAVING TERTIARY ALKYL GROUP
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PROBLEM TO BE SOLVED: To provide a method capable of obtaining an asymmetric alkyl ether having a tertiary alkyl group easily and industrially. SOLUTION: (1) There is provided a method for producing an asymmetric alkyl ether having a tertiary alkyl group by subjecting a tertiary alcohol and a primary alcohol or a secondary alcohol to a dehydration reaction using activated clay as a catalyst. (2) There is provided the method for producing an asymmetric alkyl ether having a tertiary alkyl group according to (1), where the tertiary alcohol is any one selected from the group consisting of tert-butanol, tert-amylalcohol and 1-adamantyl alcohol. SELECTED DRAWING: None COPYRIGHT: (C)2016,JPOandINPIT
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Paragraph 0023
(2017/01/31)
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- CATALYST CAPABLE OF FORMING 2,5-DIMETHYLHEXENES
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A process of making a catalyst and the catalyst composition made by that process comprising a multinuclear metal compound of the formula Ma(PCy3)b(H)c(CO)d(OR)e(H2O)f with molar ratios a:b:c:d:e:f, wherein a is in the range from 2 to 2000, b is in the range from 0 to 4000, c is in the range from 0 to 6000 and d is in the range from 0 to 2000, e is in the range from 1 to 2000, and f is in the range from 0 to 100; wherein PCy3 indicates tricyclohexylphosphine, H indicates hydride, R is an alkyl group determined by the alcohol utilized and H2O is water from the reaction; and a is at least twice w. A method of making one or more 2,5-dimethylhexenes is described. A method of making p-xylene using one or more 2,5-dimethylhexenes is also described.
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Paragraph 0052
(2015/09/23)
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- Kinetics of the reactions of tert-butanol with C2-C5 alcohols on sulfo cation exchangers
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The kinetics of etherification of tert-butanol with aliphatic alcohols on gel KU-2×8 and macroporous KU-23 sulfo cation exchangers was studied. The first order of reaction with respect to tert-butanol and the -SO3H groups of a catalyst was established. The activation energy of the process observed on KU-2×8 was 60-95 kJ/mol. It was shown that the etherification of tert-butanol on KU-2×8 occurred in a surface layer. The reactivity of primary alcohols introduced into the reaction with tert-butanol increased with their molecular weights (C2-C5). The rate of reaction with secondary alcohols was lower than that with primary alcohols.
- Golovanov,Pisareva,Levshenkov
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p. 179 - 183
(2013/05/22)
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- Specifics of the synthesis of some alkyl tert-alkyl ethers and their thermodynamic properties
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The conditions of synthesis and isolation of pure (98-99%) and extra pure (>99.9%) alkyl tert-alkyl ethers containing six to eight carbon atoms in their molecule, which are used as high-octane additives to motor fuels, were studied. The key thermodynamic properties, including melting point, density, saturated vapor pressure, enthalpy of vaporization at 298.15 K, normal boiling point, and critical parameters, obtained by experimental and calculation methods, are given. Copyright
- Krasnykh,Levanova,Karaseva,Kirgizova,Varushchenko,Druzhinina,Pashchenko
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- METHOD FOR PRODUCING OLIGOMERS DERIVED FROM BUTENES
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The invention relates to a method for producing oligomers, primarily consisting of repeating units, derived from 1 or 2-butene, from a hydrocarbon stream that essentially consists of branched and linear hydrocarbon compounds with 4 carbon atoms and contains olefinically branched and linear hydrocarbon compounds with 4 carbon atoms (parent stream C4). According to said method, a) the parent stream C4 is split into a fraction that primarily consists of linear hydrocarbon compounds with 4 carbon atoms (fraction I-C4) and a fraction that primarily consists of branched hydrocarbon compounds with 4 carbon atoms (fraction v-C4) by bringing the parent stream C4 into contact with a membrane, which allows the passage of linear hydrocarbon compounds with 4 carbon atoms more easily than branched hydrocarbon compounds with 4 carbon atoms, b) the olefinic hydrocarbon compounds with 4 carbon atoms contained in the fraction I-C4 are oligomerised, after the optional separation of butanes, c) the olefinic hydrocarbon compounds with 4 carbon atoms contained in the fraction v-C4 are subjected to one of the following steps: c1) reaction with methanol to form methyl-tert-butylether; c2) hydroformylation to essentially form isovaleraldehyde; c3) polymerisation to form polyisobutylene; c4) dimerisation to form 2,4,4-trimethyl-1-pentene; c5) alkylation to essentially form saturated hydrocarbon compounds with 8 or 9 carbon atoms.
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Page/Page column 9-10
(2008/06/13)
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- Method and device for obtaining isobutenes from conjugated hydrocarbons
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A process for isolating isobutene from a hydrocarbon mixture by a) combining the C4-hydrocarbon mixture with a primary C3- or C4-alkanol; b) reacting the isobutene in the C4-hydrocarbon mixture with the primary C3- or C4-alkanol in the presence of a heterogeneous catalyst to give the corresponding tertiary ether of isobutene, c) separating the resultant reaction mixture into the relatively low-boiling, unetherified C4-hydrocarbons and the relatively higher-boiling tertiary ether of isobutene with the aid of a distillation column, where the C4-hydrocarbons are taken off at the top, and the tertiary ether of isobutene obtained at the bottom is transferred into a reactor, d) cleaving this ether into isobutene and the corresponding primary C3- or C4-alkanol, e) distilling this mixture from d) in a further distillation column, and taking off the isobutene as the top product, which comprises carrying out step a) in a zone (4C) containing reactive internals and containing the catalyst for carrying out step b) arranged in such a way that the zone (4C) is integrated into a distillation column (4), that a reactive distillation takes place in this zone (4C), and that the C3- or C4-alkanol is fed to the distillation column above the zone (4C) and the C4-hydrocarbon mixture is fed to the distillation column below the zone (4C).
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Page column 4-5
(2008/06/13)
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- Recovery of isobutylene from commercial butane-butylene fractions
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A possibility of recovery of isobutylene with high concentration and purity from abgases of petroleum production and oil refining, e.g., from gases released in pyrolysis or catalytic cracking, by reversible reaction of isobutylene with isobutanol was studied.
- Sharonov,Rozhnov,Karaseva,Myshentseva,Barkov,Alenin
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p. 691 - 695
(2007/10/03)
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- The continuous acid-catalyzed dehydration of alcohols in supercritical fluids: A new approach to the cleaner synthesis of acetals, ketals, and ethers with high selectivity
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We report a new continuous method for forming ethers, acetals and ketals using solid acid catalysts, DELOXAN ASP or AMBERLYST 15, and supercritical fluid solvents. In the case of ether formation, we observe a high selectivity for linear alkyl ethers with little rearrangement to give branched ethers. Such rearrangement is common in conventional syntheses. Our approach is effective for a range of n-alcohols up to n-octanol and also for the secondary alcohol 2-propanol. In the reaction of phenol with an alkylating agent, the continuous reaction can be tuned to give preferential O- or C- alkylation with up to 49% O-alkylation with supercritical propene. We also investigate the synthesis of a range of cyclic ethers and show an improved method for the synthesis of THF from 1,4-butandiol under very mild conditions.
- Gray, William K.,Smail, Fiona R.,Hitzler, Martin G.,Ross, Stephen K.,Poliakoff, Martyn
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p. 10711 - 10718
(2007/10/03)
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- Hydrolysis and Alcoholysis of Esters of o-Nitrobenzenesulfonic Acid
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The rate of solvolysis of esters of o-nitrobenzenesulfonic acid with water and C1-C4 alcohols is satisfactorily described by two-parametric Hammett-Taft equation with predominating effect of the electronic factor σ*. The effect of the structure of the hydrocarbon rest in the sulfonic ester group does not fit to this relationship.
- Sendega,Makitra,Pirig
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p. 1438 - 1446
(2007/10/03)
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- Molar enthalpies of formation and vaporization of t-butoxybutanes and thermodynamics of their synthesis from a butanol and 2-methylpropene. I. Equilibria of synthesis reactions of t-butoxybutanes in the liquid phase
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The equilibria of the synthesis of 1-t-butoxybutane (I), 2-methyl-1-t-butoxypropane (II), and 1-methyl-1-t-butoxypropane (III) from 2-methylpropene (IV), and butan-1-ol (V), 2-methyl-propan-1-ol (VI), and butan-2-ol (VII) in the liquid phase were investigated at temperatures from 315 K to 423 K.On the basis of experimental equilibrium constants found for n(C4H9OH)/n = 4, values of ΔrHmdeg and ΔrSmdeg were calculated.The following results were obtained
- Sharonov, K.G.,Mishentseva, Y.B.,Rozhnov, A.M.,Miroshnichenko, E.A.,Korchatova, L.I.
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p. 141 - 145
(2007/10/02)
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- Unimolecular Reactions of Ionised Ethers
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The 12.1 eV 75 deg C electron ionisation mass spectra of 25 saturated dialkyl ethers containing between six and eight carbon atoms are reported and discussed in energetic terms.Dissociation by α-cleavage of M+. typically gives rise to intense peaks in these spectra.However, rearrangement processes, leading to eventual 1,3-O-alkyl shifts and subsequent ethyl radical loss, are also important for ionised ethers in which both alkyl groups have primary structures.Other significant ions in the spectra of n-CnH2n+1OR ethers include those formed by loss of ROH or CnH2n-1. from M+..Ionised ethers containing one secondary alkyl group tend to dissociate by α-cleavage of this group, or to a lesser extent by loss of the corresponding alkane, without undergoing such extensive rearrangements.Distonic ions and ion-molecule complexes play key roles in the isomerisation and dissociation steps involved in these fragmentations.Simple cleavages dominate the spectra of ethers containing a tertiary alkyl group.These ethers show very small or negligible M+. peaks.Ions corresponding to rupture of the C-O ?-bond, with charge retention by the hydrocarbon fragment, appear in the spectra of some ethers.There is evidence, however, that these ions may originate, at least in part, by secondary dissociations of the primary daughter ions, rather than by direct decomposition of M+..
- Bowen, Richard D.,Maccoll, Allan
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p. 147 - 155
(2007/10/02)
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- IODINE MEDIATED SYNTHESIS OF ALKYL TERTIO-ALKYL ETHERS
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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.
- Jenner G.
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p. 2445 - 2448
(2007/10/02)
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- Electron Spin Resonance Studies of Radical Addition to Methylenecycloalkanes
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E.s.r. spectroscopy has been used to investigate homolytic addition to methylenecyclo-propane, -butane, and -pentane and to the acyclic 2-methylpropene.Regiospecific addition of Me3SiO., ButOH+, and Me3Si. to the unsubstituted (tail) end of the double bond takes place with 2-methylpropene and methylenecyclo-butane and -pentane.However, although Me3Si. adds to the tail carbon of methylenecyclopropane, substituted but-3-enyl radicals result from the reactions of this alkene with Me3SiO., ButO., or ButO.H+.Ring opening thus accompanies or follows initial addition of the electrophilic radicals to the head carbon atom of methylenecyclopropane.This unusual regioselectivity is attributed to the dominance of polar effects in determining the activation energies for addition.
- Marti, Vernon P. J.,Paul, Vikram,Roberts, Brian P.
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p. 481 - 486
(2007/10/02)
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