Cyclohexene

About: Cyclohexene is a research topic. Over the lifetime, 7295 publications have been published within this topic receiving 126499 citations. The topic is also known as: Benzene tetrahydride & Tetrahydrobenzene.

The formation of highly oxidized multifunctional products in the ozonolysis of cyclohexene.

Abstract: The prompt formation of highly oxidized organic compounds in the ozonolysis of cyclohexene (C6H10) was investigated by means of laboratory experiments together with quantum chemical calculations. The experiments were performed in borosilicate glass flow tube reactors coupled to a chemical ionization atmospheric pressure interface time-of-flight mass spectrometer with a nitrate ion (NO3–)-based ionization scheme. Quantum chemical calculations were performed at the CCSD(T)-F12a/VDZ-F12//ωB97XD/aug-cc-pVTZ level, with kinetic modeling using multiconformer transition state theory, including Eckart tunneling corrections. The complementary investigation methods gave a consistent picture of a formation mechanism advancing by peroxy radical (RO2) isomerization through intramolecular hydrogen shift reactions, followed by sequential O2 addition steps, that is, RO2 autoxidation, on a time scale of seconds. Dimerization of the peroxy radicals by recombination and cross-combination reactions is in competition with the...

The partial hydrogenation of benzene to cyclohexene by nanoscale ruthenium catalysts in imidazolium ionic liquids.

Abstract: The controlled decomposition of an Ru(0) organometallic precursor dispersed in 1-n-butyl-3-methylimidazolium hexafluorophosphate (BMI.PF(6)), tetrafluoroborate (BMI.BF(4)) or trifluoromethane sulfonate (BMI.CF(3)SO(3)) ionic liquids with H(2) represents a simple and efficient method for the generation of Ru(0) nanoparticles. TEM analysis of these nanoparticles shows the formation of superstructures with diameters of approximately 57 nm that contain dispersed Ru(0) nanoparticles with diameters of 2.6+/-0.4 nm. These nanoparticles dispersed in the ionic liquids are efficient multiphase catalysts for the hydrogenation of alkenes and benzene under mild reaction conditions (4 atm, 75 degrees C). The ternary diagram (benzene/cyclohexene/BMI.PF(6)) indicated a maximum of 1 % cyclohexene concentration in BMI.PF(6), which is attained with 4 % benzene in the ionic phase. This solubility difference in the ionic liquid can be used for the extraction of cyclohexene during benzene hydrogenation by Ru catalysts suspended in BMI.PF(6). Selectivities of up to 39 % in cyclohexene can be attained at very low benzene conversion. Although the maximum yield of 2 % in cyclohexene is too low for technical applications, it represents a rare example of partial hydrogenation of benzene by soluble transition-metal nanoparticles.

Hybrid polyoxotungstate/MIL-101 materials: synthesis, characterization, and catalysis of H2O2-based alkene epoxidation.

Abstract: Polyoxotungstates [PW4O24]3− (PW4) and [PW12O40]3− (PW12) have been inserted into nanocages of the metal organic framework MIL-101. The hybrid materials PWx/MIL-101 (x = 4 or 12) containing 5−14 wt % of polyoxotungstate have been obtained and characterized by elemental analysis, N2 adsorption, FT-IR, Raman, and 31P NMR MAS spectroscopic techniques. Their catalytic performance was assessed in the selective oxidation of alkenes with aqueous hydrogen peroxide under mild reaction conditions ([H2O2] = 0.1−0.2 M, 50 °C, MeCN). PWx/MIL-101 enclosing 5 wt % of polyoxotungstate demonstrated fairly good catalytic activities in the epoxidation of various alkenes (3-carene, limonene, α-pinene, cyclohexene, cyclooctene, 1-octene), the turnover frequencies (TOF) and alkene conversions were close to the corresponding parameters achieved with homogeneous PWx. For the oxidation of substrates with aromatic groups (styrene, cis- and trans-stilbenes), a higher level of olefin conversion was attained using PW12/MIL-101. Moreo...