RELATIVE RATES OF REACTION OF OZONE WITH OLEFINS IN THE VAPOR PHASE

1960 ◽  
Vol 38 (7) ◽  
pp. 1053-1062 ◽  
Author(s):  
T. Vrbaski ◽  
R. J. Cvetanović
Keyword(s):  
Double Bond ◽  
Carbon Atom ◽  
Vapor Phase ◽  
Reaction Products ◽  
Initial Formation ◽  
Inhibiting Effect ◽  
Π Complex ◽  
Olefinic Double Bond

Relative rates of reaction of ozone with a number of olefins in the vapor phase have been determined by the use of the competitive method and GLC analysis of the reaction products. The results indicate a basic electrophilic trend onto which is superimposed a trend due to a partially inhibiting effect of the substituent groups, in particular of those on the more substituted carbon atom of the olefinic double bond. The results are discussed particularly in terms of a two-step addition process, involving an initial formation of an ozone–olefin π-complex and a slower rearrangement of the π-complex into the cyclic "initial ozonide".

Investigations on the thermal decomposition of olefins

1962 ◽  
Vol 265 (1323) ◽  
pp. 519-537 ◽  
Keyword(s):  
Nitric Oxide ◽  
Thermal Decomposition ◽  
Double Bond ◽  
Carbon Atom ◽  
Chromatographic Analysis ◽  
Indirect Method ◽  
Hydrogen Abstraction ◽  
Reaction Products ◽  
A Value ◽  
Order Of Magnitude

It has been shown that at 530 °C there is practically no decomposition of olefins not possessing b C—C bond β to the double bond. The rate constants for the decomposition of various olefins at 530 °C over the range of p 0 from 25 to 300 mm have been measured. The relative rates of decomposition and polymerization of ethylene at 530, 600 and 630 °C have been studied. On the basis of chromatographic analysis of the reaction products both in the presence and in the absence of nitric oxide it is concluded that the ethane formed comes mainly from the secondary decomposition of polymers. At 530 °C the inhibitory activity of nitric oxide is exerted only on some olefins and even then it is rather small. All olefins are, however, subject to a remarkable stimulatory activity of nitric oxide. Over the range of pressures investigated this accelerating effect on the decomposition depends linearly on the olefin and nitric oxide pressures r 0 = k 0 [RK] + k 2 [RH] [NO]. The values of the constants for different olefins have been determined. The order of magnitude of the constant k 2 was found to be the same for all olefins investigated except ethylene and propylene, the values lying between 1.0 x 10 -4 and 3.0 x 10 -4 min -1 (mm NO) -1 . Propylene, which possesses an unusually small number (3) of weak C—H bonds and only primary ones, gave (by an indirect method) the lower value (2 ± 1) x 10 -6 min -1 (mm NO) -1 . Ethylene, the only olefin without weak C—H bonds, gave (by an indirect method), a value of k 2 of about (4 ± 1) x 10 -6 min -1 (mm NO) -1 . The reaction of hydrogen abstraction from the olefin molecule by nitric oxide is assumed responsible for the stimulatory phenomenon. The low value of k 2 for ethylene compared with the values for other olefins and for paraffins can be explained as a result of the strengthening influence of the double bond on the C—H bond with the doubly bound carbon atom. The different roles of the inhibitory and accelerative functions of nitric oxide in the decomposition of paraffins and olefins are considered to be mainly responsible for the changes in the shape of the ∆p –time curves as P NO is varied. On this basis the phenomenon of the apparently transistory activity of nitric oxide as an inhibitor in some cases can be explained.

Hydrogenolytic opening of 4,4-dimethyl-4a,5-epoxy-a-homocholestane derivatives and mass spectra of some reaction products

1983 ◽  
Vol 48 (3) ◽  
pp. 937-955 ◽  
Author(s):  
Helena Velgová ◽  
Antonín Trka
Keyword(s):  
Double Bond ◽  
Carbon Atom ◽  
Mass Spectra ◽  
Molecular Ions ◽  
Fragmentation Process ◽  
Epoxide Ring ◽  
Allylic Alcohols ◽  
Reaction Products ◽  
Metastable Peak ◽  
Reaction Proceeds

The hydrogenolytic opening of the epoxide ring of all four stereoisomeric 3-acetoxy-4,4-dimethyl-4a,5-epoxy-A-homocholestanes was investigated. The reaction proceeds at the more substituted carbon atom C(5), giving rise to 4a-hydroxy-5,6-unsaturated derivatives. The hydrogenation of the 5,6-double bond of these allylic alcohols affords 4,4-dimethyl-A-homo-5β-cholestane derivatives. The mass spectra of 3,4a-diketones XI and XVII and 4a-ketones XVI and XXVIII to XXX were also studied. In the case of the saturated diketone XVII it was observed that the most abundant metastable peak corresponds to a two-step fragmentation process. The decomposition of the molecular ion of the unsaturated diketone XI is associated with ring A expansion. The mass spectra of 3-acetoxy ketones XVI and XXVIII are characterized by an elimination of a C4H8 molecule from the contracted ring A of the ion [M-CH3COOH]+. The unexpected elimination of the species C6H11, C6H12, and C6H13 from the ring A of the molecular ions of 3-hydroxy ketones XXIX and XXX is shown to be preceded by hydroxyl migration and ring A rearrangement.

MOLECULAR REARRANGEMENTS IN THE REACTIONS OF OXYGEN ATOMS WITH OLEFINS

1958 ◽  
Vol 36 (4) ◽  
pp. 623-634 ◽  
Author(s):  
R. J. Cvetanović
Keyword(s):  
Double Bond ◽  
Carbon Atom ◽  
Internal Migration ◽  
Degrees Of Freedom ◽  
Large Fraction ◽  
Heats Of Reaction ◽  
Trans Butene ◽  
Pressure Independent ◽  
Olefinic Double Bond ◽  
Oxygen Atoms

Reactions of oxygen atoms with propylene, butene-1, iso-butene, cis-butene-2, trans-butene-2, cis-pentene-2, and tetramethyl ethylene have been studied at room temperature and at pressures between 50 and 600 mm. The following generalizations can be made. The oxygen atom adds predominantly to the "less-substituted" carbon atom of the olefinic double bond to form a short-lived biradical which rapidly rearranges into isomeric epoxy and carbonyl compounds. Rearrangements involve migration of radicals (including H atoms) from the carbon atom to which oxygen is attached to the other carbon atom of the original double bond. Partly inhibited rotation around the original double bond also takes place. Migration of H atoms is exclusively internal. Migration of larger radicals, such as CH3, is only partly internal: a large fraction of these radicals become completely detached from the rest of the molecule and the particular carbonyl compound is produced both by radical combination and by internal migration. The fragmentation resulting from the splitting off of a migrating radical is pressure independent. The final addition products formed are "hot" as a result of high heats of reaction and undergo decomposition if the excess energy is not removed by collisions. This second type of fragmentation is, therefore, pressure dependent. It is very extensive in the case of ethylene and appears to be completely suppressed in the investigated pressure range in the case of more complex olefins (possessing a greater number of degrees of freedom) such as butenes and higher homologues. Propylene exhibits an intermediate behavior. For orientation of addition of oxygen atoms a carbon atom of an olefinic double bond to which CH3 is attached is "less substituted" than a corresponding carbon atom to which C2H5 is attached.

ÉTARD REACTION: III. NATURE OF THE COMPLEX

1960 ◽  
Vol 38 (11) ◽  
pp. 2136-2142 ◽  
Author(s):  
Owen H. Wheeler
Keyword(s):  
Magnetic Susceptibility ◽  
Reaction Mechanism ◽  
Chloride Complex ◽  
Initial Formation ◽  
Spectroscopic Evidence ◽  
Chromyl Chloride ◽  
Π Complex ◽  
Products Of Reaction

Magnetic susceptibility measurements have shown that the chromium atoms in the toluene–chromyl chloride complex are tetravalent. The structure of the complex and the reaction mechanism are discussed. Spectroscopic evidence has been found of the initial formation of a π-complex. The products of reaction of chromyl chloride and ethylbenzene, isopropylbenzene, tetralin, and indane have been determined.

ChemInform Abstract: Electroreduction of the Activated Olefinic Double Bond in Some 2-Aryl-1(2-acetylamino-1,3,4-thiadiazol-5-yl)-propionitrile Derivatives

ChemInform ◽  
1987 ◽  
Vol 18 (23) ◽  
Author(s):  
M. ABDEL AZZEM ◽  
M. M. M. RAMIZ ◽  
E. A. GHALI ◽  
H. M. FAHMY ◽  
M. R. H. ELMOGHAYAR
Keyword(s):  
Double Bond ◽  
Olefinic Double Bond

Oxydation du cyclohexène par le nitrate cérique d'ammonium

1974 ◽  
Vol 52 (18) ◽  
pp. 3201-3205 ◽  
Author(s):  
Claude Briguet ◽  
Christian Freppel ◽  
Jean-Claude Richer ◽  
Miklos Zador
Keyword(s):  
Double Bond ◽  
Ammonium Nitrate ◽  
Ceric Ammonium Nitrate ◽  
Olefinic Double Bond

The oxidation of cyclohexene by ceric ammonium nitrate has been studied. In anhydrous DMSO the reaction leads to cyclohexene-3-nitrate, while in acetonitrile N-(cyclohexene-2-yl) acetamide is formed. Hydroxylated products are formed in the presence of water. The results obtained are explained in terms of the formation of an intermediate arising from the addition of the radical NO3• to the olefinic double bond. [Journal translation]

Electrochemical Heterodifunctionalization of α-CF3 Alkenes to Access α-Trifluoromethyl-β-sulfonyl Tertiary Alcohols

2021 ◽  
Author(s):  
Zhi-Peng Ye ◽  
Jie Gao ◽  
Xin-Yu Duan ◽  
Jianping Guan ◽  
Fang Liu ◽  
...  
Keyword(s):  
Double Bond ◽  
Hydroxyl Group ◽  
Tertiary Alcohols ◽  
Olefinic Double Bond

An unprecedented electrochemical heterodifunctionalization of α-CF3 alkenes with benzenesulfonyl hydrazides was accomplished in this work, wherein a β-sulfonyl and a α-hydroxyl group were simultaneously incorporated across the olefinic double bond...

Heterometallische Cluster durch ligandunterstützte Metallfragmentkondensation / Heterometallic Clusters by Ligand Assisted Metal Fragment Condensation

1991 ◽  
Vol 46 (9) ◽  
pp. 1169-1176 ◽  
Author(s):  
Wolfgang Rohde ◽  
Gert Fendesak
Keyword(s):  
Double Bond ◽  
Chelate Complexes ◽  
Heterometallic Clusters ◽  
X Ray ◽  
X Ray Crystallography ◽  
Inert Solvent ◽  
Fragment Condensation ◽  
Olefinic Double Bond ◽  
High Yields ◽  
Iron Fragment

Dicobalt complexes of 3-vinylpropargylic alcohol derivatives react with biscyclooctenetricarbonyliron to give new chelate complexes of the iron tricarbonyl fragment with the olefinic double bond and the alcohol oxygen atom bound to the iron fragment. These compounds react upon heating in an inert solvent to give FeCo-alkynyl cluster complexes in high yields. One of these compounds has been structurally characterized by X-ray crystallography.

Proximity Effect in Arene Pi-Complex Formation

1966 ◽  
Vol 21 (9) ◽  
pp. 823-827 ◽  
Author(s):  
Minoru Tsutsui ◽  
Morris N. Levy
Keyword(s):  
Complex Formation ◽  
Proximity Effect ◽  
Grignard Reagent ◽  
Reaction System ◽  
Coupling Reaction ◽  
Reaction Products ◽  
Hydrogen Elimination ◽  
Trans Stilbene ◽  
Π Complex ◽  
Aryl Grignard Reagent

A proximity effect in arene π-complex formation from the reaction system of an aryl Grignard reagent and anhydrous chromic chloride was investigated. The yields of arene π-complexes and any accompanying reaction products were compared by the systematic variation of the aryl Grignard reagent employed. Phenyl Grignard gave the best yield of π-complex followed by the benzyl, mesityl and β-ethyl phenyl analogues. The styryl and phenylacetylenyl analogues did not form any π-complexes.The coupling reaction of benzyl groups gave a new π-complex, π-bibenzyl-π-toluene chromium, along with toluene, bibenzyl and trans-stilbene.Trans-stilbene was found without forming a trace amount of cis-stilbene. A mechanism for this stereospecific and α-hydrogen elimination coupling reaction is proposed.

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