Theoretical study of reaction mechanism for CH₂CHX(XH, F, Cl) with ozone

Abstract

ABSTRACT:In this work, we study the reaction mechanism of the CH 2 CHX(XAH, F, Cl) with ozone reactions, using ab initio MP2 method at 6-311ϩϩg** basis set level. The geometric configurations of reactants, intermediates, transition states, and products were optimized, and the energies were obtained at the QCISD(T)/6-311ϩϩG** level. The transition states and intermediates of the reactions were verified by the vibrational analysis. The results show that the ozonolysis of ethylene and its derivatives is reasonable and believable along the Criegee mechanism. The results also show that the activation energies of the controlling steps along the fluoroethylene and chloroethylene with ozone reaction pathways were lower than that along the ethylene with ozone reaction pathway. That is to say, the derivatives of ethylene have the higher activity to react with ozone and deplete the ozone layer.

Ozonolysis of methyl, amino and nitro substituted ethenes: A semi-empirical molecular orbital study

“…Appreciable theoretical work has been done on alkene ozonolysis [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38]. An AM1 study of the ozonolysis of ethene and 2-butene confirmed the Criegee mechanism and gave good predictions regarding stereochemistry [23].…”

“…The product yields are in reasonable agreement with experimental results under atmospheric conditions. Li et al [35] used the MP2/6-311++G ** strategy to study ozonolysis of substituted ethenes, where halo substitution was predicted to lower the activation barriers. CCSD and CCSD(T) investigations on both isomers of the carbonyl oxide and dioxirane intermediates has been carried out by employing DZ+P and TZ+2P basis sets, confirming that the carbonyl oxide possesses more zwitterionic character than dioxirane as predicted [36].…”

Peroxide intermediates of oxidation processes: Organic trioxides

“…In a series of theoretical papers 244 -252 , the Criegee mechanism was fully confirmed for the reactions of ozone with ethylene, fluoro-and chloroethylene 248,251 , propene 249 , benzene and phenol 250 , and acetylene 252 . The relative energies of ozonolysis participants are listed in Table 15.…”

(-)-Hydroxylindestrenolide, a New Sesquiterpenoid from a Gorgonian Coral Menella sp. (Plexauridae)

“…

In previous studies, a series of interesting secondary metabolites including steroids, 1-3) guaiane lactones, 4,5) briarane diterpenoids, 3) menellin A (a highly oxygenated racemate with C 8 skeleton), 3) picolinic acid N-methyl betaine, 1,6) n-hexadecanol, 1) 9H-purin-6-amino-N-9-dimethyl, 1) thymidine, 1) and batyl alcohol, 1,7) had been reported from the gorgonian corals belonging to the genus Menella, collected off the South China Sea. In a continuation of our search for bioactive substances from marine invertebrates, a specimen of gorgonian coral identified as Menella sp., collected off southern Taiwan coast, was studied.

…”

“…Based on these findings, the C-8 hydroxy group in 1 should be a-oriented by comparison the structure of 1 with that of 2. Chemical investigations of the gorgonian corals belonging to the genus Menella have afforded a diverse range of secondary metabolites, [1][2][3][4][5][6][7] however, the sesquiterpenoids possessing the carbon skeleton as presented as 1 are rarely found in marine organisms. 12) In bioactivity testing, sesquiterpenoid 1 was found to exhibit marginal cytotoxicity toward HL-60 human promyelocytic leukemia and K562 human erythromyeloblastoid leukemia tumor cells (IC 50 ϭ15.6, 38.7 mg/ml), respectively, but not active toward DU-145 human prostate tumor cells IC 50 Ͼ40 mg/ml).…”