N-Hydroxyphthalimide as a Catalyst of Cumene Oxidation with Hydroperoxide (original) (raw)
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A new class of lipophilic N-hydroxyphthalimides catalysts designed for the aerobic oxidation of cumene in solvent-free conditions were synthesized and tested. The specific strategy proposed for the introduction of lipophilic tails on the NHPI moiety leads to lipophilic catalysts which, while completely preserving the activity of the precursor, allow to conduct the catalytic oxidation in neat cumene for the very first time. The corresponding cumyl hydroperoxide is obtained in good yields (28-52%) and high selectivity (95-97%), under mild conditions. Importantly, the presence of a polar solvent is no longer required to guarantee the complete solubilization of the catalyst. On the other hand, the oxidation conducted in neat cumene unearths the unexpected necessity of using small amounts of acetonitrile in order to fully promote the hydrogen atom transfer process and prevent the catalyst from detrimental hydrogen bond (HB) driven aggregation.
Monatshefte für Chemie - Chemical Monthly, 2010
Oxidation of cumene with 1-methyl-1-phenylethyl hydroperoxide in the presence of copper chloride/ phase transfer catalytic systems was investigated by ESI-MS. For catalytically active copper(II) chloride/crown ethers, copper(II) chloride/crown ethers/alkaline metal salts, and copper(II) chloride/tetrabutylammonium chloride systems, the presence of a few kinds of copper complexes in the organic phase was detected by use of ESI-MS. When copper(II) chloride/podand systems were used, the conversion of hydroperoxide and the yield of oxidation product were close to zero, although the concentration of copper complexes in the organic phase was high. Addition of bis(2-hydroxyethyl) ether to the catalytically active copper(II) chloride/18-crown-6 system resulted in an inhibition effect.
Solvent and catalytic metal effects on the decomposition of cumene hydroperoxide
Ind Eng Chem Res, 1989
Kinetic information is presented on the decomposition of cumene hydroperoxide at 110 " C and 60-380 bar in supercritical krypton, xenon, carbon dioxide, propane, and chlorodifluoromethane and a t ambient pressure in liquid octane, l-octene, l-hexanol, and cyclohexanol. The supercritical reaction studies are performed with a high-pressure reactor constructed of 316 stainless steel (316SS), gold-plated 316SS, and Teflon-coated 31621s. The magnitude of the reaction rate constant is a strong function of the metals present during the reaction and of the ability of the solvent to hydrogen bond or complex with the activated complex of cumene hydroperoxide, and it is a weak function of hydrostatic pressure and solution viscosity over the pressure ranges investigated. Gold, 316SS, and aluminum facilitate the formation of geminate radicals, while gold also affects the selectivity of the reaction. Transition-state theory is used to interpret the reaction data.
A contribution to the study of thermal decomposition of cumene hydroperoxide
Collection of Czechoslovak Chemical Communications, 1973
An analysis of the kinetics and mechanism of thermal decomposition of cumene hydro peroxide in n-heptane within 120-170°C is presented. It follows from the results that besides the homolytic dissociation of peroxidic bond also a chain process is involved in'the decomposition of this peroxide. The kinetic analysis suggests a considerable participation of methyl radicals in thjs process. These radicals are formed through the fragmentation of primary cumyloxy radicals. The rate constants of both processes that are kinetically monomolecular have been expressed by corresponding Arrhenius equations. Thermal decomposition of cumene hydroperoxide has been a subject of interest of several authors 1-5. From the published data it follows that even a pure radical decomposition of this peroxide is not a simple reaction. The thermal dissociation is accpmpanied by several consecutive or parallel elementary processes. Using kinetic analysis of the mechanism of decomposition reaction we attempted to describe the overall decomposition of cumene hydroperoxide more quantitatively i.e. including the loss of this compound caused by a chain process. For this reason the overall rate of peroxide decomposition was determined. The kinetics of primary monomolecular process were established by the inhibition of the chain reaction, Finally, when eliminating the original initiation step, the rate and order of the induced decomposition could be determined. The experiments were carried out in n-heptane within temperature region 120-170°C. EXPERIMENTAL Cumene hydroperoxide was purified by isolating its. sodium salt from a commercial product. The salt was then decomposed by acetic acid and the peroxide formed was separated by distillation at 65°CjO'2 Torr. The peroxide obtained was 99'1% pure (iodometrical assay). n-Heptane employed as a reaction medium for peroxide decomposition was of analytical grade and it was used without further purification. The purification of N-phenyl-~-naphthyJamine, used as a radical scavenger, was effected by four times repeated recrystallization from ethanol; M.p. 108°C was identical with tabelled data for a pure compound 6. To be able to determine the amount of peroxide decomposition due to chain reaction and that
Selectivity of metal polyphthalocyanine catalyzed oxidation of cumene
Reaction Kinetics and Catalysis Letters, 1983
Metal polyphthaloeyanines enhance the rate of cumene oxidation and decrease the selectivity to cumene hydroperoxide. Formation of cumyl alcohol as main by-product depends on the initial rate of oxidation or reaction time. I~OIIH~bTa.rIOIJMaHHHbl MeTaIITIOB IIOBbIlllalOT CKOpOCTb OKHCYleHH~I KyMozla H nortrlX<alOT ce~eKTHBHOCTb o6pa3OBaHHa raAponepeKrlCH KyMoJIa. O6pa3oBaHtle KyMOJIOBOFO cnHpTa, KaK FJIaBHOFO no6oql-IOFO lIpOJIyKTa, 3aBHCHT OT HaqaBbHO~ cKOpOCTH OKHcJIe-HHa HJIH peaKILHOHHOFO BpeMeHa.
Autocatalytic Decomposition of Cumene Hydroperoxide at Low Temperature Conditions
2000
Cumene Hydroperoxide (CHP) has been used in the production of Dicumyl Hydroperoxide (DCPO) and phenol. In Taiwan, several severe fire or explosion incidents have occurred due to its thermal instability or reactivity. In this research, the exothermic decomposition of CHP in Cumene was characterized by isothermal microcalorimeter, TAM (thermal activity monitor), because isothermal testing offers the advantage of thermal equilibrium