Olefin oxidation products

The above mechanism suggested that the use of olefin activators other than paUadium(lI), which are not capable of promoting the p-hydride elimination, may lead to other types of olefin oxidization products, such as epoxides. Since thallium(in) is a known oxidant for olefin epoxidation, it was therefore postulated that replacement of the palladium(II) activator by T1(III) benzoate in the C0-NO2/NO redox system would lead to the accomplishment of olefin epoxidation [118]. 

DMA solutions of the analogous iridium(I) complex, [IrQ(C8Hi4)2]2 absorb O2 irreversibly with expulsion of free cyclooctene to the solution [480]. No evidence of any olefin oxidation products was found. Oxygen uptake measurements in benzene solution gave O2 Ir ratios of 0.6 to 1.1 depending on the conditions, and the reaction products exhibited IR bands at 830 cm (coordinated dioxygen) and 1260cm" (possibly the OH of hydroperoxide). This iridium system was not effective at ambient conditions for olefin oxidation. 

Table 9 Olefin Oxidation Products Using Mo(CO)6 Catalyst in SCCO2 (263)... 

For example, olefin sulfuri2ation products (Lubrizol, 1980), dithiophosphomolybdates (Mobil, 1980), or more simply the dithiophosphates of alcohol (Shell, 1980) whose anti-oxidant properties have been announced, are used in oil formulations for their anti-wear properties. 

Prospective Processes. There has been much effort invested in examining routes to acetic acid by olefin oxidation or from ethylene, butenes, or j -butyl acetate. No product from these sources is known to have reached the world market the cost of the raw materials is generally prohibitive. 

The lowest members of the series of perfluoroalkanedicarboxyhc acids have been prepared and are stable compounds. They have been synthesized by oxidation of the appropriate chlorofluoroolefin as well as by electrochemical fluorination and direct fluorination. Perfluoromalonic acid is an oxidation product of CH2=CHCE2CH=CH2 (21). Perfluorosuccinic acid has been produced by oxidation of the appropriate olefin (see eq. 7) (5) or by electrochemical fluorination of succinyl chloride or butyrolactone (41) and subsequent hydrolysis. 

Interest in synthetic naphthenic acid has grown as the supply of natural product has fluctuated. Oxidation of naphthene-based hydrocarbons has been studied extensively (35—37), but no commercially viable processes are known. Extensive purification schemes must be employed to maximize naphthene content in the feedstock and remove hydroxy acids and nonacidic by-products from the oxidation product. Free-radical addition of carboxylic acids to olefins (38,39) and addition of unsaturated fatty acids to cycloparaffins (40) have also been studied but have not been commercialized. 

Reaction of olefin oxides (epoxides) to produce poly(oxyalkylene) ether derivatives is the etherification of polyols of greatest commercial importance. Epoxides used include ethylene oxide, propylene oxide, and epichl orohydrin. The products of oxyalkylation have the same number of hydroxyl groups per mole as the starting polyol. Examples include the poly(oxypropylene) ethers of sorbitol (130) and lactitol (131), usually formed in the presence of an alkaline catalyst such as potassium hydroxide. Reaction of epichl orohydrin and isosorbide leads to the bisglycidyl ether (132). A polysubstituted carboxyethyl ether of mannitol has been obtained by the interaction of mannitol with acrylonitrile followed by hydrolysis of the intermediate cyanoethyl ether (133). 

Oxidation. The chlorine atom [22537-15-17-initiated, gas-phase oxidation of vinyl chloride yields 74% formyl chloride [2565-30-2] and 25% CO at high oxygen [7782-44-7], O2, to CI2 ratios it is unique among the chloro olefin oxidations because CO is a major initial product and because the reaction proceeds by a nonchain path at high O2/CI2 ratios. The rate of the gas-phase reaction of chlorine atoms with vinyl chloride has been measured (39). 

Use of DMF as a solvent for the oxidation of l-o1efins has been reported by Clement and Selwitz. The method requires only a catalytic amount of PdCl2 and gives satisfactory yields under mild conditions. A small amount of olefin migration product is the only noticeable contaminant in the cases reported. The procedure can be applied satisfactorily to various 1-olefins with other functional groups. This useful synthetic method for the preparation of methyl ketones has been applied extensively in the syntheses of natural products such as steroids,macrolides, dihydrojasmone, and muscone. " A comprehensive review article on the palladium-catalyzed oxidation of olefins has... 

A large number of DTDAFs ( electron-rich olefins ) described above are very efficient donors, e.g., for their application in organic conductors however they are highly sensitive to air. Studies aimed at the preparation of such compounds, especially the aliphatic ones, have so far met with only limited success. For example, a few alkyl-substituted DTDAF derivatives could be detected electrochemically, but an attempt to isolate one of these only led to oxidation products (91JA985). Similarly, an elec-... 

The main method to obtain propylene oxide is chlorohydrination followed by epoxidation. This older method still holds a dominant role in propylene oxide production. Chlorohydrination is the reaction between an olefin and hypochlorous acid. When propylene is the reactant, propylene chlorohydrin is produced. The reaction occurs at approximately 35°C and normal pressure without any catalyst ... 

Anhydride and sulfone formation are not the only side reactions. Other side reactions lead to colored products (excess S03, high temperatures), traces of disulfonic acid, olefins, and oxidation products. 

The Pacman catalyst selectively oxidized a broad range of organic substrates including sulfides to the corresponding sulfoxides and olefins to epoxides and ketones. However, cyclohexene gave a typical autoxidation product distribution yielding the allylic oxidation products 2-cyclohexene-l-ol (12%) and 2-cyclohexene-1-one (73%) and the epoxide with 15% yield [115]. 

The same structure was proposed later by Hock and Schrader [40]. It became clear only in 1939 when Criegee et al. [41] proved that peroxide formed by cyclohexene oxidation has the structure of hydroperoxide. Later studies, performed by Farmer and Sutton [42], greatly extended the number of hydroperoxides as products of olefin oxidation. Beginning from the later part of the 20th century, the chain theory of organic compound oxidation became the theoretical ground for the experimental study in this field. The main events of the development of oxidation chemistry before the chain theory of oxidation are presented in Table 1.1. 

Although the reaction of a titanium carbene complex with an olefin generally affords the olefin metathesis product, in certain cases the intermediate titanacyclobutane may decompose through reductive elimination to give a cyclopropane. A small amount of the cyclopropane derivative is produced by the reaction of titanocene-methylidene with isobutene or ethene in the presence of triethylamine or THF [8], In order to accelerate the reductive elimination from titanacyclobutane to form the cyclopropane, oxidation with iodine is required (Scheme 14.21) [36], The stereochemistry obtained indicates that this reaction proceeds through the formation of y-iodoalkyltitanium species 46 and 47. A subsequent intramolecular SN2 reaction produces the cyclopropane. 

The results of the olefin oxidation catalyzed by 19, 57, and 59-62 are summarized in Tables VI-VIII. Table VI shows that linear terminal olefins are selectively oxidized to 2-ketones, whereas cyclic olefins (cyclohexene and norbomene) are selectively oxidized to epoxides. Cyclopentene shows exceptional behavior, it is oxidized exclusively to cyclopentanone without any production of epoxypentane. This exception would be brought about by the more restrained and planar pen-tene ring, compared with other larger cyclic nonplanar olefins in Table VI, but the exact reason is not yet known. Linear inner olefin, 2-octene, is oxidized to both 2- and 3-octanones. 2-Methyl-2-butene is oxidized to 3-methyl-2-butanone, while ethyl vinyl ether is oxidized to acetaldehyde and ethyl alcohol. These products were identified by NMR, but could not be quantitatively determined because of the existence of overlapping small peaks in the GC chart. The last reaction corresponds to oxidative hydrolysis of ethyl vinyl ether. Those olefins having bulky (a-methylstyrene, j8-methylstyrene, and allylbenzene) or electon-withdrawing substituents (1-bromo-l-propene, 1-chloro-l-pro-pene, fumalonitrile, acrylonitrile, and methylacrylate) are not oxidized. 

Lee and Chang (1978) have compared the ability of linear polyethers, crown ethers, and quaternary ammonium compounds to catalyse oxidations with KMn04 under liquid-liquid and liquid-solid conditions. In the presence of acetic acid as a scavenger for the KOH produced, the products of olefin oxidation were carboxylic acids, diones, diols and ketols. The three different classes of catalysts exhibited about the same activity in liquid-solid systems. 

In addition to the [2-I-2-I-1] carbocyclization, an analogous [3-I-2-I-1] version has been reported [23]. The high 7r-character of the rr-bond of the cyclopropane provides reactivity similar to that of an olefin thus when the 4-pentynyl cyclopropanes 42 were subjected to the PK reaction conditions, the bicyclo[4.3.0]nonenone 43, in addition to a small amount of the oxidized product 44, was afforded in modest yield (Eq. 7). The analogous transformation with the vicinally disubstituted cyclopropane 45 furnished regioisomers 46 and 47, in which cleavage at the less substituted bond is favored (Eq. 8). 

The formation of oxidation products a-c in a range of G values (0.7-3.8) during the 7-R of S in 02-saturated DCE suggests that a-c would be produced from complicated reactions of peroxy radicals with S (Table 5). On the other hand, the regioselective formation of 3d with large G values (2.6-3.0) in oxidation of 3 with O2 is explained by spin localization on the p-olefinic carbon because of the contribution of (B) in 3. The results of products analyses are essentially identical with prediction based on k and ko for S measured with PR. It should be emphasized that the reactivities of c-t unimolecular isomerization and reaction of S with O2 can be understood in terms of charge-spin separation induced by p-MeO. 

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