Olefin five-carbon

The noncondensable hydrocarbons comprise the hydrocarbons having less than five carbon atoms methane, ethane, propane and butanes encountered in production refining will add the olefins and diolefins ... 

The initial products of beta-scission are an olefin and a new carbenium ion (Equation 4-9). The newly-formed carbenium ion will then continue a series of chain reactions. Small ions (four-carbon or five-carbon) can transfer the positive charge to a big molecule, and the big molecule can crack. Cracking does not eliminate the positive charge it stays until two ions collide. The smaller ions are more stable and will not crack, They survive until they transfer their charge to a big molecule,... 

Unlike common five and six membered heterocycles, purines rarely undergo coupling reactions including the insertion of an olefin or carbon monoxide. This behaviour is not well understood since Heck and CO insertion reactions are known to proceed on similar systems. 

The photolysis of cyclobutanone in the presence of 20- to 50-fold excess of ethylene has been reported (17). In this instance various five-carbon olefins but not cyclopentane are said to be observed among the products. The hydrocarbons are believed to be formed by a reaction between a tri-... 

The gas remaining after oil recovery, called pyrolytic gas, or pyro-gas, is typically composed of paraffins and olefins with carbon numbers from one to five. Depending on the process, the heat value of the gas can range from 170 to 2,375 Btu per cubic foot, and averages 835 Btu per cubic foot.4 (Natural gas averages around 1000 Btu per cubic foot.) Most processes use the pyrolytic gas as fuel to heat the reactor. Any surplus gas can be flared or used to replace natural gas as boiler fuel. Emissions from burning... 

Metallocenes (Fig. 2) are sandwich structures, typically incorporating a transition metal such as titanium, zirconium, or hafnium in the center. The metal atom is linked to two aromatic rings with five carbon atoms and to two other groups—often chlorine or alkyl. The rings play a key role in the polymerization activity (23-27). Electrons associated with the rings influence the metal, modifying its propensity to attack carbon-carbon double bonds of the olefins. The activities of these metallocenes combined by aluminum alkyls, however, are too low to be of commercial interest. Activation with methylaluminoxane, however, causes them to become 10-100 times more active than Ziegler-Natta catalysts. 

Cyclo-olefins are subject to structural isomerization in contact with acidic catalysts, as Bloch and Thomas (27) and Greensfelder and Voge (21) have shown. Therefore, such catalytic activity when intimately coupled to the aromatization reaction may direct the reaction path to products having five-carbon ring structures which cannot aromatize ... 

The computing time required to create reaction paths is similar to that reported in Fig. A2 only few seconds are required for radicals with carbon atoms lower than five to six while almost a week is needed for olefins with carbon number larger than 16. 

Taking the special case above secondary-secondary cracking by /1-scission of ions from a family of tribranched paraffins with 16 carbon atoms, into mono-branched olefins with five carbon atoms and into monobranched ions with 11 carbon atoms. Two types of complex are involved in this type of elementary... 

The search for new reactivity and new reactions is an important target in homogeneous catalysis. A declared goal is the selective activation of C-H bonds under mild conditions. Although there are numerous examples of stoichiometric C-H bond oxidative additions to transition metal centers, successful examples regarding catalytic functionalization of C-H bonds have been made only during the last five years. Notable advances have been achieved by Moore and coworkers who described in 1992 the ortAo-acylation of pyridine with olefins and carbon monoxide. The cluster compound triruthenium dodecacarbonyl has been used as catalyst (Scheme 10). 

Watkins and O Deen cover a wide temperature range and give an excellent Arrhenius plot. For the more complex olefins and for acetylenes, there is quite a scatter of results (Table 53), but kinetic data are missing for many of the three-, four- and five-carbon alkenes. Data on the addition of Cj H5 to a variety of vinyl monomers with various hetero-atoms are given in Table 54. 

The present chapter is limited to oxidation of lower olefins, especially those with two to five carbon atoms, over solid catalysts in the vapor phase. Patent literature is given scant attention, but journal literature is covered through 1965. Liquid phase oxidation with homogeneous catalysts has recently grown in importance, but such studies are excluded from this chapter. A review of the oxidation of ethylene to acetaldehyde with PdClg solutions is given by Smidt (3). 

Skeletal isomerization of linear olefins with four and five carbon atoms... 

Thus, the three-carbon and the five-carbon chelated tt complexes of cobalt are more stable than the four- or six-carbon or probably larger ring complexes. Substituents on the coordinating olefinic group affect the stability of the cyclic complexes. traiw-Methyl groups decrease the relative stability of the cyclic structures. Crotonylcobalt carbonyl, at 0°C under 1 atm of carbon monoxide, exists as an equiUbrium mixture containing 56% of the open-chain complex and 44% of the cyclic tt complex. 

The hydroformylation of aryl olefins with a chain length of preferentially five carbon atoms was claimed by BASF (Scheme 6.71) [184]. As a catalyst, unmodified... 

Natural rubber can be regarded as a 1,4-addition polymer of isoprene. The basic building block of five carbons for the polymerization is 3-isopentenyIpyro-phosphate (3-IPP). The first reaction is an enzymatic isomerization of the olefin of 3-IPP to 2-isopentenylpyrophosphate (2-IPP). The carbon-carbon bond formation between these two pyrophosphates initiates the polymerization in which the pyrophosphate group acts as a leaving group. The isoprene units of natural rubber are all linked in a head-to-tail fashion and all of the double bonds have a cis-structure. The stereocontrol of the formation of the cis-unit is achieved by the function of the elongation factor which combines with the famesyl pyrophosphate (FPP) synthase [16]. 

Reaction of [2- " C]acetone with vinylmagnesium bromide (Figure 6.75, Procedure A) provided 2-methyl-3-[2- " C]buten-2-ol (257), which upon treatment with PBra rearranged to give 3,3-dimethyl[3- " C]allyl bromide (258). The latter was used for the alkylation of ethyl acetoacetate, thereby extending the carbon skeleton of the /3-keto ester by a labeled five-carbon (isoprenyl) unit. The initially formed alkylated intermediate 259 was not isolated but immediately saponified and decarboxylated to give ketone 260. Subsequent Homer-Wadsworth-Emmons olefination and reduction of the separated trans-ester 261 converted 260 into [T- Clgeraniol 12621. 

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