Kinetics of 2-methyl-2-pentene epoxidation with tert-butyl hydroperoxide

The reaction rate at the initial period during the epoxidation of 2-methyl-2-pentene with tert-butyl hydroperoxide in the presence of Mo(CO)₆ as catalyst varies linearly in the range of lower concentrations of olefin, hydroperoxide and catalyst. The reaction is losing the first order character in the region of higher concentrations due to the inhibition with the reaction products. This finds the confirmations in a discrepancy between the concentration and the instantaneous (temporal) reaction order.     

Reaction of perfluoro-2-methyl-2-pentene with thiourea

The reaction of perfluoro-2-methyl-2-pentene with thiourea in aprotic bipolar solvents gives 4,4-bis(trifluoro-methyl-5-(tetrafluoroethylidene)-2-aminodihydrothiazole, the structure of which was confirmed by ¹⁹F and ¹³C NMR and x-ray structural analyses. The mechanism of the reaction is discussed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 253–256, February, 1993.     

Radiation-induced copolymerization of hexafluoroacetone with 2-methyl-1-pentene

Copolymerization of hexafluoroacetone (HFA) with 2-methyl-1-pentene (2MP) in trichlorotrifluoroethane (R-113) was carried out by γ-ray irradiation in a low-temperature region of ?100 to 0°C. Though HFA does not homopolymerize and 2MP scarcely does, the copolymerization took place at various monomer compositions. The copolymerization rate and the molecular weight in the low-temperature region were much higher than those at 0°C. Above room temperature the copolymerization did not take place and only the adduct of monomers was formed. The copolymerization was inhibited to some extent by cation scavengers, but not by radical or electron scavengers. Elemental analysis and nuclear magnetic resonance (NMR) spectra show that the copolymer consists of almost equimolar monomer units and has two types of structure, head to tail and head to head or tail to tail. It has been concluded that copolymerization probably proceeds via a cationic mechanism to form an alternating copolymer.     

Reaction of perfluoro-2-methyl-2-pentene with bifunctional mucleophiles

Conclusion Bifunctional O- and S-nucleophiles react with perfluoro-2-methyl-2-pentene to form five- and seven-membered heterocycles in a ratio which is determined by the type of nucleophile.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2066–2076, September, 1985.     

TS-1 zeolite microengineered reactors for 1-pentene epoxidation

A zeolite-based microengineered reactor was fabricated and tested for 1-pentene epoxidation over titanium silicalite-1 (TS-1) catalyst, which has been selectively incorporated within the microreactor channel using a new synthesis procedure.     

Electrochemical addition of fluorosulfonic acid to perfluoro-2-methyl-3-isopropyl-2-pentene

Electrolysis of fluorosulfonic acid in the presence of perfluoro-2-methyl-3-isopropyl-2-pentene yields the products of addition of HSO₃F at the double bond — 2-hydro-3-fluorosulfatoperfluoro-2-methyl-3-isopropylpentane and 2-fluorosulfato-3-hydroperfluoro-2-methyl-3-isopropylpentane. The formation of monofluorosulfates probably includes the stage of one-electron reduction of the initial olefin.A. N. Nesmeyanov Institute of Organoelemental Compounds, Russian Academy of Sciences, 117813 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 5, pp. 1208–1210, May, 1992.     

ESR spectra of spin-adducts of hydroxyalkyl radicals with perfluoro-4-methyl-2-pentene

A study was carried out on the ESR spectra of the spin-adducts of hydroxyalkyl radicals with perfluoro-4-methyl-2-pentene (I) formed upon the photolysis of alcoholic solutions of this perfluoroolefin. The stable conformational positions of the substituents in the spin-adducts depend on the structure of the hydroxyalkyl radicals. The spin-adducts are annihilated as a consequence of hydrogen atom abstraction as indicated in a preparative experiment.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 730–732, March, 1991.     

Synthesis of Partially Fluorinated Organic Compounds from Perfluoro-2-methyl-2-pentene and Phenol Derivatives

The reactions of perfluoro-2-methyl-2-pentene with substituted phenols and some heterocyclic compounds containing OH group result in the substitution of the fluorine atom either exclusively at the internal multiple bond or at the terminal multiple bond of perfluoro-2-methyl-1-pentene formed by isomerization of the starting perfluoroolefin in the course of the reaction. The reaction pathway depends on the reaction conditions, base used, and substituents in the benzene ring. The structures of the compounds were confirmed by ¹H, ¹³C, and ¹⁹F NMR and IR spectroscopy.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 3, 2005, pp. 430–437.Original Russian Text Copyright © 2005 by Furin, Zhuzhgov, Chi, Kim.     

Formation of long-lived radicals in addition reactions to perfluoro-4-methyl-2-pentene

Conclusions The photolysis of liquid solutions of CF₃I and (CF₃)₂CFI in perfluoro-4-methyl-2-pentene at 240 run gives longlived radicals, which were identified as radical-adducts formed by the addition of CF₃ and (CF₃)₂CF radicals to the double bond of the perfluorolefin.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 184–185, January, 1989.     

Formation of long-lived radicals in radiolysis of perfluoro(4-methyl-2-pentene)

Conclusions On the basis of the EPR spectrum of perfluoro(4-methyl-2-pentene) (PMP) that has been exposed to gamma radiation at 77–300 K, three types of long-lived radicals have been observed, with lifetimes greater than two years. With increases in the radiolysis temperature for radiation dose, the concentration of long-lived radicals increases. Their relative concentrations depend on the irradiation conditions and the thawing schedule.Under certain conditions, long-lived radicals of a single type can be obtained from the PMP.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1263–1268, June, 1988.     

Unprecedented and Effective Synthesis of Thiazolines from Perfluoro-3-isothiocyanato-2-methyl-2-pentene and Certain P-Nucleofuges

The reactions of perfluoro-3-isothiocyanato-2-methyl-2-pentene with PPh₃ and P(NEt₂)₃ in the presence of NaBF₄, KI, and NaBPh4 form phosphonium salts with the heterocyclic substituent (4E)-5,5-bis(trifluoromethyl)-4-(tetrafluoroethylidene)-4,5-dihydro-1,3-thiazol-2-yl, instead of involving desulfurization and formation of P-F-containing products. The reaction with tris(pentafluorophenyl)phosphine fails. The reactions with P(OEt)₃ in the presence of ClSiMe₃ or (CH₃O)₂POSiMe₃ yield diethyl or dimethyl [(4E)-5,5-bis(trifluoromethyl)-4-(tetrafluoroethylidene)-4,5-dihydro-1,3-thiazol-2-yl]phosphonates and no intramolecular alkylation products. The ¹H, ¹³C, ¹⁹F, and ³¹P spectra are presented, and the reaction pathways are discussed. Potential mechanisms of the biological and catalytic activity of the reaction products are considered.     

H2S-promoted thermal isomerization of cis-2-pentene to 1-pentene and trans-2-pentene around 800 K

H₂S accelerates the thermal isomerization of cis-2-pentene (P2c) to 1-pentene (P1) and trans-2-pentene (P2t) to around 800 K. This effect is interpreted on the basis of a free radical mechanism in which 2-pentenyl and thiyl radicals are the main chain carriers. P1 formation is essentially explained by the competing processes: P2t formation is due to addition-elimination processes: the importance of which has been evaluated against process (?4μ): The following ratios of rate constants have been measured and are discussed: (RT in cal mol^?1).     

Cyclocondensation of F-2-methyl-2-pentene with activated methylene compounds using ‘freeze-dried’ potassium fluoride

The reactions of $\text{F}$-2-methyl-2-pentene with activated methylene compounds such as acetylacetone, ethyl acetoacetate, benzoylacetonitrile, and benzoylmethyl perfluoroalkyl ketones in the presence of potassium fluoride were carried out. Each reaction proceeded smoothly in acetonitrile at room temperature by using ‘freeze-dried’ potassium fluoride as a condensing agent. Acetylacetone and ethyl acetoacetate gave both divinyl ether and pyran compounds, whereas other activated methylene compounds afforded only pyrans in good yields.     

Gas sorption-induced dilation of poly(4-methyl-1-pentene)

Sorption and volume dilation isotherms of semicrystalline poly(4-methyl-1-pentene) (PMP) were measured using CO₂ and C₃H₈ as penetrants, which have sieving diameters of 3.3 and 4.3 Å, respectively. On the other hand, the PMP crystal has a void width of approximately 4 Å as estimated by X-ray diffraction, so it was anticipated that CO₂ would be able to sorb into the PMP crystal while C₃H₈ would not. The data show that C₃H₈ has a constant partial molar volume of approximately 87 cc/mol, just above the value reported in other rubbery polymers, and are consistent with the hypothesis that the C₃H₈ molecules are too large to sorb into the PMP crystals. The partial molar volume of CO₂ was found to be 39 cc/mol for CO₂ weight fractions of up to 0.03. Since the typical partial molar volume of CO₂ in rubbery materials is 46 cc/mol, the lower values in this study were attributed to CO₂ sorption into crystalline regions of the polymer, which provided no dilation. Application of a two-phase model using the assumption of Henry's law sorption showed that apparently all C₃H₈ sorption was occurring in the amorphous region but approximately 16% of CO₂ sorption occurred in the crystalline regions. © 1996 John Wiley & Sons, Inc.     

Crystal structure of isotactic poly(4-methyl-1-pentene)

The crystal structure of isotactic poly(4-methyl-1-pentene) was determined by x-ray analysis. The unit cell is tetragonal, P4 b2, with α = 18.70 Å and c (fiber axis) = 13.68 Å; it contains four molecular chains each consisting of seven monomeric units in the fiber period. The molecular conformation is essentially a (7/2) helix, but deviates slightly from the uniform (7/2) helix. The unusual low density is discussed from the structural point of view.