Department of Chemical Engineering Itsaso Auzmendi Murua, Jason Hudzik Joseph W.
Davies, Kent, Freelance Writer has reference to this Academic Journal, PHwiki organized this Journal Department of Chemical Engineering Itsaso Auzmendi Murua, Jason Hudzik Joseph W. Bozzelli Chemical Activation Reactions of Cyclic Alkane in addition to Ether Ring-Opened Diradicals with O2: Thermochemistry, Reaction Paths, Kinetics 7th International Conference on Chemical Kinetics, July 10-14, 2011 Cyclic Aliphatic Hydrocarbons are major components in modern fuels: – Present in reactants: Commertial jet fuel contains: 26% cycloalkanes in addition to alkylcycloalkanes Commercial diesel fuel (up to 40%) in addition to gasoline (up to 3%) – Produced during the gas-phase processes During combustion or pyrolisis processes, cycloalkanes can lead to as long as mation of: – Toxic compounds or soot precursors such as benzene (via dehydrogenation) – Linear unsaturated species such as acrolein (via ring opening) 3 to 6 member cyclic ethers are as long as med at early times by alkyl radical reactions with dioxygen in combustion in addition to pre-combustion processes that occur at moderate T. Introduction Introduction s-butane oxidation Formation of Cyclic Ethers in Alkyl Radical Oxidation R. + O2 => ROO. Hydrogen atom transfer then Cyclic ether as long as med with OH elimination
This Particular University is Related to this Particular Journal
Introduction s- in addition to t- isooctane oxidation Formation of Cyclic Ethers In Isooctane Radical + O2 Reactions Initial unimolecular dissociation reactions of cyclic alkanes in addition to ethers in combustion systems are ring opening to as long as m a di-alkyl radical. Release of ring strain in small ( 3 to 5 member ring) in addition to bicyclic molecules reduces the bond energy needed as long as bond cleavage – ring opening Diradical Formation. The initial ring opened di-radical or the peroxy alkyl di-radical can undergo triplet singlet conversion by: Electronic state crossing Collisions of the di-alkyl radical with the bath gas Chemical activation reaction of one radical site via association with 3O2 Introduction Introduction This study is an attempt to determine the importance of the diradicals reacting with dioxygen. Quantum chemical calculations as long as thermochemical properties. Statistical rate theory as long as the T in addition to P dependence of the rate coefficient Systems Studied : Cyclic Alkanes : y(ccc), y(cccc) in addition to y(ccccc) Cyclic Ethers : y(cco), y(ccco) in addition to y(cccco) TCD (C10H16) Tri-cyclo Decane Tri-cyclo Decane
Thermochemical Properties Use of computational chemistry calculate as long as radicals in addition to molecules: – Heats of as long as mation – Entropies – Heat capacities Heat of as long as martion from Isodesmic work reactions: () Sirjean, B., et al. J. Phys. Chem. A 2006, 110, 12693. Association in addition to addition reactions are treated as: Chemical activation reactions with: Quantum Rice Ramsperger Kassel analysis as long as k(E) Master Equation as long as fall-off (pressure dependant reactions) Steady State Analysis as long as Activated Species Input file as long as Chemaster: Thermochemical in as long as mation on reaction paths Temperature in addition to pressures desired as long as study Frequencies of the species involved in the reactions High Pressure Rate Constants Lennard Jones Collision Parameters of reactants in addition to the bath gas Edown in addition to Eaverage as long as the determination of k(E) Rate Constants Excited (A) can: Dissociate back to reactants Be stabilized by collisions React to new products Chemaster QRRK in addition to ME analysis Energy levels from one External Rotation included in density of states
P in addition to T dependence of rate constants Chemical activation Di-radical + O2 only c.ccc. + o2 Chemical activation analysis is used as long as reaction of the diradicals with O2 : – qRRK as long as k(E) – Master Equation Analysis as long as fall-off Chemkin used as long as analysis of a reaction system of the diradical Chemkin analysis includes: Results (kinetics) from diradical with O2 (chemical activation association) Triplet-Singlet conversion Formation of oxygenated ring Hrxn = exothermic ~ 70 kcal mol-1 Ring opening via cleavage of weak cyclic O-O bond ~ 45 kcal mol-1 Unimolecular reactions of the diradical: Intramolecular H transfer to as long as m an stable olefin -scission to as long as m olefins + New Radical Reactions of stabilized intermediates -scission in addition to Ring closure Reaction of the diradicals with O2 Reaction Paths Example – Cyclobutane – y(cccc) Unimolecular Dissociation Chemical Activation
Intramolecular H transfers in addition to HO2 elimination reactions C.CCC.+ O2 C.CCCQ. Kinetic Parameters H transfer in addition to HO2 elimination rxns CHEMKIN MODELING RESULTS
Reaction Paths Cyclopropane y(ccc) Unimolecular Dissociation Chemical Activation Reaction Products Cyclopropane y(ccc) Main reaction paths: Ring closure then reaction to y(cco) + CH2O At higher temperatures: Formation of ethylene becomes important by unimolecular dissociation of C.CC. 1 atm Reaction Paths Cyclobutane – y(cccc) Unimolecular Dissociation Chemical Activation Small C4 system : 3 kcal mol-1 barrier to beta scission is low
Reaction Products Cyclobutane y(cccc) 1 atm Unimolecular dissociation to two ethylene moieties is the most important channel under both temperatures. At 500 K Oxidation to two as long as maldehyde plus ethylene is next most important At 1200 K Intramolecular H transfer to as long as m stable butene is most important Formation of oxitane (cy- CCCO) Some importance at 500K Negligible at 1200K. Reaction Paths Cyclopentane y(ccccc) Chemical Activation Unimolecular Dissociation Reaction Products Cyclopentane y(ccccc) 1 atm () At 500K pentene in addition to y(cccco) are major product in addition to overlap At 1200K, pentene is mayor product in addition to ch2o, y(cccco), y(ccc) in addition to ch2ch2 are all similar At 500 K Formation of pentene in addition to cyclopropane are the main reaction paths. Formation of two CH2O plus ethylene in addition to singlet diradical 1CH2 are also important At 1200 K Intramolecular H transfer – Formation of pentene is the dominant reaction path
Reaction Paths Oxirane Cyclic ether y(cco) Unimolecular Dissociation Chemical Activation Reaction Products Oxirane Cyclic ether y(cco) 1 atm Formation of CH2O in addition to HCO2. are dominant at both temperatures At 500 K Ring closure resulting on y(coo) has some importance At 1200 K Formation of a as long as maldehyde in addition to the singlet diradical 1CH2 Reaction Paths Oxetane Cyclic ether y(ccco) Chemical Activation Unimolecular Dissociation
Reaction Products Oxetane Cyclic ether y(ccco) 1 atm Formation of a as long as maldehyde plus ethylene most important at both temperatures At 500 K Ring closure of stabilized intermediate o.cco. has importance At 1200 K Formation of coc=c has importance Reaction Paths Cyclic Ethers y(cccco) It can -scission to as long as m two different diradicals Reaction Paths Cyclic Ethers y(cccco) 1 Unimolecular Dissociation Chemical Activation
() At 500K ch2o in addition to y(cccoo) are dominant in addition to overlap At 1200K ch2o in addition to y(ccc)are dominant in addition to overlap At 500 K Formation of as long as maldehyde in addition to ring closure to as long as m y(cccoo) most important At 1200K Formation of two as long as maldehyde plus cyclopropane becomes the dominant path Reaction channels Cyclic Ethers y(cccco) 1 Reaction Paths Cyclic Ethers y(cccco) 2 Unimolecular Dissociation Chemical Activation () At 500K ch2o in addition to y(cocco) are dominant in addition to overlap At 1200K ch2ch2 in addition to y(cco) are dominant in addition to overlap Reaction channels Cyclic Ethers y(cccco) 2 At 500 K Formation of as long as maldehyde in addition to ring closure to as long as m y(cocco) most important At 1200 K Ring closure to as long as m as long as maldehyde plus the three memebered cyclic ether becomes the dominant reaction path.
1 atm Both T Formation of YC5YC5E is the main reaction path Formation of butadioene (C=CC=C) has some importance Formation of 1,4 pentadiene (C=CCC=C) some importance Lower T Formation of YC5.PN=O. important reaction path Formation of YC5=OYC5OH some importance Reaction Products JP10 C10H16 – Tri-cyclodecane Conclusions Re as long as mation of cycle fast function of Ring-Opening Further reactions Most ring opening occurs at high temperature -scission -scission in addition to intramolecular H transfer reactions with low barriers exist these dominant C.CCC. 2 C2H4 Ea = 3.0 kcal mol-1 O.CCCCO. O=CCCCOH Ea = 2.3 kcal mol-1 Where -scission in addition to intramolecular H transfer reactions are typical (Ea ~ 14-20 kcal mol-1) Reactions with O2 become important at low T Ring closure from chemical activation intermediate species Future Work
Davies, Kent Freelance Writer
Davies, Kent is from United States and they belong to Davies, Kent and they are from Phoenix, United States got related to this Particular Journal. and Davies, Kent deal with the subjects like Business; Careers/Occupations; History; Management; Retailing; Travel
Journal Ratings by Argosy University
This Particular Journal got reviewed and rated by Argosy University and short form of this particular Institution is US and gave this Journal an Excellent Rating.