103110-88-9Relevant academic research and scientific papers
Oxidation Chemistry of Propene in the Autoignition Region: Arrhenius Parameters for the Allyl + O2 Reaction Pathways and Kinetic Data for Initiation Reactions
Stothard, Nigel D.,Walker, Raymond W.
, p. 2621 - 2630 (1992)
The oxidation of propene has been studied at a total pressure of 60 Torr between 400 and 520 deg C, and a detailed product analysis made in the initial stages of reaction over a wide range of mixture composition.Mechanisms for the formation of the products are discussed.The initial rates of formation of hexa-1,5-diene (HDE) and carbon monoxide are used to obtain A8 = 109.66 +/- 0.35 dm3 mol-1 s-1 and E8 = 78.6 +/- 4.5 kJ mol-1, the former giving from the known value of k1 CH2=CHCH2* + CH2=CHCH2* -> CH2=CHCH2CH2CH=CH2 (1).CH2=CHCH2* + O2 -> CO + products.Arrhenius parameters are also given for alternative pathways of the allyl + O2 reaction.All involve high energy barriers.From measurements of the accelerating effect of small amounts of additives CH3CHO, HCHO, HDE and propene oxide, rate constants at 480 deg C are obtained (for the first three) for the initiation reaction (21) RH + O2 -> R + HO2.Very few independent data for this type of reaction are available.The accelerating effect of propene oxide is ascribed to an exothermic isomerisation product which is not thermally stabilised at 60 Torr and undergoes homolysis to radical fragments.HDE is shown to have a spectacular accelerating effect on propene oxidation and values of k21n/k10 = 1050 +/- 200 at 480 deg C is obtained.C3H6 + O2 -> CH2=CHCH2* + H2O.HDE + O2 -> *CH2CH=CHCH2CH=CH2 + H2O.
Arrhenius Parameter for the Addition of HO2 Radicals to (E)-But-2-ene over the Range 400 - 520 deg C
Stothard, Nigel D.,Walker, Raymond W.
, p. 2115 - 2119 (1990)
Studies have been made of the addition of HO2 radicals to (E)-but-2-ene in the temperature range 400 - 520 deg C, by use of the co-oxidation of (E)-but-2-ene and propene in the presence of tetramethylbutane as a source of HO2 radicals.From measurements of the relative yields of 2,3-dimethyloxirane and methyloxirane and the known Arrhenius parameters for reaction (6), values of A7 = 108.61 +/- 0.30 dm3 mol-1 s-1 and E7 = 50.0 +/- 4 kJ mol-1 have been obtained. .The values are compared with data for HO2 addition to other alkenes.The excellent correlation between the activation energy for addition and the ionisation energy of the alkene is used to provide a kinetic data base for HO2 addition to alkenes over the range 600-1000 K, where the reactions are of major importance.From studies of the relative yields of 2,3-dimethyloxirane and (Z)-but-2-ene from (E)-but-2-ene + H2 + O2 mixtures, further evidence is presented to show that the decomposition of hydroperoxyalkyl radicals, such as CH3CH(OOH)CHCH3, into alkene + HO2 is at most a minor process compared with formation of an oxirane + OH radical.
Oxygenation with Molecular Oxygen. Thermal and Photochemical Epoxidation of Propylene in the Presence of Sulfur Dioxide in Acetonitrile at Ambient Temperature
Sasaki, Tadahiro
, p. 3882 - 3886 (1981)
Irradiation of a mixture of propylene and sulfur dioxide in acetonitrile at ice-cold temperature causes absorption of molecular oxygen and gives propylene oxide as the sole volatile product.Also, in the absence of light, the addition of nitrile or nitrate salts to a mixture of sulfur dioxide and propylene in acetonitrile under oxygen at room temperature leads to the smooth formation of propylene oxide as the only volatile product.Both reactions show quite similar solvent dependence and are retarded by the additives with ionization potentials lower than ca. 9.5 eV.The main byproduct is poly(propylenesulfonate).The mechanisms of the epoxidation reactions are discussed.
Catalytic epoxidation of olefins in the presence of a vanadyl porphyrin complex
Miralamov,Mamedov
, p. 25 - 27 (2006)
It was found that vanadyl porphyrin complexes synthesized from petroleum metal porphyrin concentrates stimulated epoxidation during the olefin oxygenation process. The yields of obtained oxiranes turned out to be 38-75%, depending on the olefin structure. An epoxidation mechanism that suggests the formation of a protonated dioxygen adduct as an intermediate during oxygenation of olefins in the presence of vanadyl porphyrin complexes was proposed. An analogy is drawn between the epoxide formation reaction upon the catalytic oxygenation of olefins and the Prilezhaev reaction. MAIK "Nauka/Interperiodica".
Gas-phase dehydration of vicinal diols to epoxides: Dehydrative epoxidation over a Cs/SiO2 catalyst
Kim, Tae Yong,Baek, Jayeon,Song, Chyan Kyung,Yun, Yang Sik,Park, Dae Sung,Kim, Wooyoung,Han, Jeong Woo,Yi, Jongheop
, p. 85 - 99 (2015)
A novel type of dehydration reaction that produces epoxides from vicinal diols (dehydrative epoxidation) using a basic catalyst is reported. Epoxyethane, 1,2-epoxypropane, and 2,3-epoxybutane were produced from the dehydrative epoxidation of ethylene glycol, 1,2-propanediol, and 2,3-butanediol, respectively. Among a number of tested basic catalysts, the Cs/SiO2 catalyst showed outstanding performance for the dehydrative epoxidation of 2,3-butanediol and is considered to be the most promising catalyst for this type of reaction. In order to identify the superiority of the Cs/SiO2 catalyst and a mechanism of the reaction, structure-activity relationships were studied along with density functional theory (DFT) calculations. The following features are found to be responsible for the excellent activity of the Cs/SiO2 catalyst: i) strong basic sites formed by Cs+, ii) low penetration of Cs+ into SiO2 which permits basic sites to be accessible to the reactant, iii) stable basic sites due to the strong interactions between Cs+ and SiO2 surface, and iv) mildly acidic surface of SiO2 which is advantageous for the elimination to H2O. In addition, the dehydrative epoxidation involves an inversion of chirality (e.g. meso-2,3-butanediol (R,S) to trans-2,3-epoxybutane (R,R or S,S)), which is in agreement with DFT results that the reaction follows a stereospecific SN2-like mechanism.
2,3-Butanediol dehydration catalyzed by silica-supported alkali phosphates
Kim, Wooyoung,Shin, Wookyun,Lee, Kyoung Jun,Cho, YongSeok,Kim, Hyung Soon,Filimonov, Igor N.
, p. 148 - 163 (2019)
Characterization of acid-base centers and catalytic dehydration of 2,3-butanediol (BDO) was performed over a wide range of silica-supported alkali phosphates (M_P/SiO2; M = Na, K, Cs; M:P = 0.5–3 mol:mol). Selectivity to 1,3-butadiene (BD) and 3-butene-2-ol (3B2OL) formed by elimination correlates with the densities of conjugated acid-base pairs and increases in the order Na ??M+ moieties. Isolated Br?nsted acid centers are probably silica grafted phosphoric acid molecules at low M/P and –PO(OH)2 end groups of oligophosphates at M/P > 1.5. Deactivation rate increases with the increase of M/P ratio in order Na K Cs. Deactivation patterns imply that sites responsible for elimination are active in dehydrative epoxidation. Dehydration of 3B2OL smoothly proceeds to BD, but the catalysts deactivate faster compared to BDO dehydration.
Stopped-Flow Studies of the Mechanisms of Ozone-Alkene Reactions in the Gas Phase: trans-2-Butene
Martinez, Richard I.,Herron, John T.
, p. 4644 - 4648 (1988)
The reaction of ozone with trans-2-butene has been studied in the gas phase at 294 K and 530 Pa (4 Torr) by using a stopped-flow reactor coupled to a photoionization mass spectrometer.The concentrations of reactants and products were determined as a function of reaction time.A mechanism is proposed to account for the observed products: CH3CHO, H2CO, CO2, CH4, CF3C(O)C(H)(OH)CH3, H2C=C=O, H2O, 2-butanone, 2,3-epoxybutane, CH3C(O)C(O)CH3, and HC(O)C(O)H.This work again indicates that simple "hot" ester hypothesis needs to be critically reconsidered for gas-phase ozonolysis.
Reactions Involving Hot O(3P) Atoms and Isomeric 2-Butene
Ferrieri, Richard A.,Wolf, Alfred P.
, p. 4747 - 4752 (1992)
The low-pressure gas-phase investigation is reported on the reactions involving high-energy O(3P) atoms with cis- and trans-butene.Gas chromatographic analysis of stable hydrocarbon end products revealed a complex spectrum of compounds containing carbonyl, epoxide, and alcohol groups.The large distribution of alcohol products was a distinct feature in these hot atom systems, indicating that OH radical formation was important.These analyses revealed differences in the internal energy levels of the reaction intermediates formed through the greater pressure dependence exhibited by the degree of stereospecific addition of oxygen atoms to trans-butene then reaction with cis-butene and through the greater degree of internal rearrangement and carbon-carbon bond scission exhibited by the trans intermediate.Direct measurements using on-line mass spectrometry also revealed that CO product signals were 14.6 times higher from reactions with cis-butene than with trans-butene, indicating greater reactivity of the cis ?-bond toward oxygen atom attack.Similarly, these direct analyses revealed that OH product signals were 1.7 times higher from reactions with cis-butene, suggesting that in addition to direct H abstraction an indirect pathway involving mutual interaction with the substrate's ?-bond may have contributed, in part, to those OH products observed in these studies.Kinetic energy moderator studies supported this hypothesis through the different moderator dependencies exhibited by the OH product signals seen to arise from high-energy oxygen atom reactions with the two stereoisomers.
The Mechanism of Ozone-Alkene Reactions in the Gas Phase. A Mass Spectrometric Study of the Reactions of Eight Linear and Branched-Chain Alkenes
Martinez, Richard I.,Herron, John T.,Huie, Robert E.
, p. 3807 - 3820 (1981)
The stable products of the low-pressure (4 - 8 torr (1 torr = 133.33 Pa)) gas-phase reactions of ozone with ethene, propene, 2-methylpropene, cis-2-butene, trans-2-butene, trans-2-pentene, 2,3-dimethyl-2-butene, and 2-ethyl-1-butene have been identified by using a photoionization mass spectrometer coupled to a stirred-flow reactor.The products observed are characteristic of (i) a primary Criegee split to an oxoalkane (aldehyde or ketone) and a Criegee intermediate, (ii) reactions of the Criegee intermediates such as unimolecular decomposition, secondary ozonide formation, etc., and (iii) secondary alkene chemistry involving OH and other free-radical products formed by the unimolecular decomposition of the Criegee intermediates.The secondary OH - alkene - O2 reactions account for a significant fraction of the alkene (CnH2n) consumed and lead to characteristic products such as Cn dioxoalkanes nH2n + 30)>, Cn acyloins nH2n + 32)>, and Cn alkanediols nH2n + 34)>.Cn oxoalkanes and Cn epoxyalkanes observed at m/e (CnH2n + 16) are probably formed primarily via epoxidation of the alkene by O3.A general mechanism has been proposed to account for the observations.
Oxidation of lower alkenes by Α-oxygen (FeIII–O??)Α on the FeZSM-5 surface: The epoxidation or the allylic oxidation?
Starokon, Eugeny V.,Malykhin, Sergei E.,Parfenov, Mikhail V.,Zhidomirov, Georgy M.,Kharitonov, Alexander S.
, p. 43 - 51 (2017/11/15)
Reactions of anion-radical α-oxygen (FeIII–O??)α with propylene and 1-butene on sodium-modified FeZSM-5 zeolites were studied in the temperature range from ?60 to 25 °C. Products were extracted from the zeolite surface and identified. It was found that main reaction pathway was the epoxides formation. Selectivity for epoxides at ?60 °C was 59–64%. Other products were formed as a result of secondary transformations of epoxides on the zeolite surface. According to IR spectroscopy, the oxidation of propylene over the entire temperature range and 1-butene at ?60 °C were not accompanied by the formation of (FeIII–OH)α groups, in distinction to methane oxidation. This testifies that hydrogen abstraction does not occur. In case of 1-butene reaction with α-oxygen at 25 °C, hydrogen abstraction occurred but was insignificant, ca 7%. According to DFT calculation ferraoxetane intermediate formation is preferable over hydrogen abstraction. Following decomposition of this intermediate leads to the propylene oxide (PO) formation. The results may be relevant to the low selectivity problem of the silver catalyst in propylene epoxidation and raise doubts about the presently accepted mechanism explaining an adverse effect of allylic hydrogen.
