Oct-3-ene

The more recently developed so-called linear low-density polyethylenes are virtually free of long chain branches but do contain short side chains as a result of copolymerising ethylene with a smaller amount of a higher alkene such as oct-1-ene. Such branching interferes with the ability of the polymer to crystallise as with the older low-density polymers and like them have low densities. The word linear in this case is used to imply the absence of long chain branches. 

Some comparative data for a VLDPE copolymer based on ethylene and oct-1-ene and an EVA material (91% ethylene, 9% vinyl acetate) are given in Table 10.7. 

Recently, Liew et al. reported the use of chitosan-stabilized Pt and Pd colloidal particles as catalysts for olefin hydrogenation [51]. The nanocatalysts with a diameter ca. 2 nm were produced from PdCl2 and K2PtCl4 upon reduction with sodium borohydride in the presence of chitosan, a commercial biopolymer, under various molar ratios. These colloids were used for the hydrogenation of oct-1-ene and cyclooctene in methanol at atmospheric pressure and 30 °C. The catalytic activities in term of turnover frequency (TOF mol. product mol. metal-1 h-1)... 

More recently, during research aimed at supporting the highly linear selective hydroformylation catalyst [Rh(H)(Xantphos)(CO)2] onto a silica support, the presence of a cationic rhodium precursor in equilibrium with the desired rhodium hydride hydroformylation catalyst was observed. The presence of this complex gave the resulting catalyst considerable hydrogenation activity such that high yields of linear nonanol could be obtained from oct-1-ene by domino hy-droformylation-reduction reaction [75]. 

The advantage of this mesoporous TS-1 over samples prepared by the conventional route is illustrated in Fig. 34. The two samples behave similarly for the oxidation of linear reactant oct-1-ene. But a marked difference was observed for the oxidation of bulkier cyclohexene. Because of the absence of diffusional constraints, the catalytic epoxidation activity in the mesoporous TS-1 enhanced by almost an order of magnitude for the oxidation of the bulkier cyclohexene. 

Fig. 34. Ratio of product concentrations [sum of epoxide and secondary products (a) from oct-1 -ene and (b) from cyclohexene] obtained with mesoporous and conventional TS-1 as a function of the contact time. The results show that the mesoporous TS-1 has a similar activity for oct-1 -ene epoxidation as conventional TS-1. However, the mesoporous TS-1 is significantly more active for cyclohexene epoxidation [Reproduced from Schmidt et al. (188) by permission of the Royal Society of Chemistry].

The rate also decreases with an increase in the chain length of the alkene molecule (hex-l-ene > oct-1-ene > dodec-l-ene). Although the latter phenomenon is attributed mainly to diffusion constraints for longer molecules in the MFI pores, the former (enhanced reactivity of terminal alkenes) is interesting, especially because the reactivity in epoxidations by organometallic complexes in solution is usually determined by the electron density at the double bond, which increases with alkyl substitution. On this basis, hex-3-ene and hex-2-ene would be expected to be more reactive than the terminal alkene hex-l-ene. The reverse sequence shown in Table XIV is a consequence of the steric hindrance in the neighborhood of the double bond, which hinders adsorption on the electrophilic oxo-titanium species on the surface. This observation highlights the fact that in reactions catalyzed by solids, adsorption constraints are superimposed on the inherent reactivity features of the chemical reaction as well as the diffiisional constraints. 

The products of the selective electrochemical fluorination of butadiene with platinum electrodes in amine/ HF mixtures, particularly Et,N 3HF, were 3,4-difluorobut-1-cnc and 1,4-difluorobut-2-ene in a ratio of 1 2, 2.3-dimethyIbut-2-enc gave 2.3-difluoro-2,3-dimelhylbutane (yield 22%), while 2-mcthylbut-2-ene gave 2,3-difluoro-2-methyIbutanc (yield 23%) and 2,2-difluoro-3-methylbutane (yield 11 %). Oct-1-ene could not be fluorinated instead, the solvent degraded. Volatile degradation products were acetaldehyde, acetyl fluoride and fluorocthane. 

Concerning the substrate oct-1-ene 99, the normal products 100 and 101 could be formed via [2a + 2S] transition states, however, in the event of re-face attack, more severe interactions of R with the environment could open an alternative radical pathway leading to N-alkylation. 

The mechanism of the unprecedented chromium-catalysed selective tetramerization of ethylene to oct-1-ene has been investigated. The unusually high oct-1-ene selectivity of this reaction apparently results from the unique extended metallacyclic mechanism in operation. Both oct-1-ene and higher alk-l-enes were formed by further ethylene insertion into a metallacycloheptane intermediate, whereas hex-1-ene was formed by elimination from this species as in other trimerization reactions. Further mechanistic support was obtained by deuterium labelling studies, analysis of the molar distribution of alk-l-ene products, and identification of secondary co-oligomerization reaction products. A bimetallic disproportionation mechanism was proposed to account for the available data.120... 

Crotylmetallation of-y-heterosubstituted vinyl lithium derivatives preparation of (3/ , 4S, 5S )-3,4-dimethyl-5-ferf-butoxy-oct-1-ene... 

The following alkenes have been hydroxylated by these methods (method, stirring time, yield %) dicyclopentadiene (A, 4 hours, 86%) oct-1-ene (4, 2 hours, 85%) (1) cyclohexene (B, 1 hour, 86%) cyclooctene (B, 1 hour, 73%). 

These OsL3H4 complexes have an extensive chemistry, representative examples of which are illustrated in scheme 12. In the presence of hydrogen, Os(PEtPh2)3H4 catalyzes the hydrogenation of oct-1-ene.276 Photolysis of Os(PMe2Ph)3H4 gives a reactive intermediate Os(PMe2Ph)3H2 (see above). 

TRICARBOMETHOXY-2-PHENYLSULFON YLBICYCLO 3.3.Q]OCT-1-ENE (Benzene, 1,1 -[[1,2-bls(methylene)-1,2-ethanedlyl]bls(sulfonyl)]bls-)... 

D. trans-4,7,7-Tricarbomethoxy-2-phenylsulfonylbicyclo[3.3.0]oct-1-ene. In a flame-dried, 2-L, three-necked, round-bottomed flask equipped with a magnetic stirrer, dropping funnel, and nitrogen inlet, is placed 1.44 g of sodium hydride (60% in oil, 36.0 mmol) which has been washed twice with 50 mL of hexane and then suspended In 500 mL of anhydrous THF. To the above mixture is added 7.59 g (33.0 mmol) of dimethyl (E)-5-methoxycarbonyl-2-hexenedioate in 50 mL of THF. After being stirred at 0°C for 30 min, a solution containing 10.02 g (30.0 mmol) of 2,3-bis(phenylsulfonyl)-1,3-butadiene in 900 mL of anhydrous THF is added over 30 min. The solution is stirred for 10 min at 0°C and then quenched with 100 mL of a saturated aqueous ammonium chloride solution. The solvent is removed under reduced pressure, and... 

ANIONIC ELECTROCYCLIZA-TION USING 2,3-BIS(PHENYL-SULFONYLJ-1,3-BUTADIENE trans-4,7,7-TRICARBOMETHOXY-2-PHENYL-SULFONYLBICYCLO[3.3 0]OCT-1 -ENE... 

Classical catalysis of the addition by a redox system utilizes iron or copper salts. The usual catalyst is copper(I) chloride which is slowly oxidized by moist air to yield a green mixture of copper(I) and copper(II) salts. The example of the addition of 1,2-dibromo-l-chloro-l,2,2-trifluoroethane to oct-1 -ene to give 5 shows selective carbon-halogen homolytic cleavage.8,86... 

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