Ethene-propene

These equations represent the adsorption-desorption reactions and the surface reaction E, P, and B are, respectively, ethene, propene, and 2-butene, and s represents an active site. If the surface reaction is rate deter-... 

Ethene/propene/diene monomer rubbers (EPDM) are elastomeric terpoly-mers used in the production of sealants, tubing and gaskets and, in the USA, is used in roofing applications. As the name suggests they are prepared by the polymerization of mixtures of ethene, propene and diene monomers, to form cross-links. By far the most common diene used is 5-ethylidene-2-norbomene (ENB). 

Small olefins, notably ethylene (ethene), propene, and butene, form the building blocks of the petrochemical industry. These molecules originate among others from the FCC process, but they are also manufactured by the steam cracking of naphtha. A wealth of reactions is based on olefins. As examples, we discuss here the epoxida-tion of ethylene and the partial oxidation of propylene, as well as the polymerization of ethylene and propylene. 

Naphthalene dioxygenase from P. putida strain FI is able to oxidize a number of haloge-nated ethenes, propenes, and butenes, and d5 -hept-2-ene and cis-oct-2-ene (Lange and Wackett 1997). Alkenes with halogen and methyl substituents at double bonds form allyl alcohols, whereas those with only alkyl or chloromethyl groups form diols. 

The relative reactivity profile of the simple alkenes toward Wacker oxidation is quite shallow and in the order ethene > propene > 1-butene > Zi-2-butene > Z-2-butene.102 This order indicates that steric factors outweigh electronic effects and is consistent with substantial nucleophilic character in the rate-determining step. (Compare with oxymercuration see Part A, Section 5.8.) The addition step is believed to occur by an internal ligand transfer through a four-center mechanism, leading to syn addition. 

The Chemistry of Regiospecificity in Unsymmetrically Substituted Bromonium Ions Bromonium Ions of Ethene, Propene, and 2-Methylpropene... 

In the laboratories of Natta in Milan it was found that the Ziegler catalysts could polymerize (besides ethene) propene, styrene, and several a-olefins to high linear polymers. These polymers appeared crystalline when examined by X-ray diffraction techniques and were able to give oriented fibers. In less than one year since the preparation of the first polymer of propene, Natta was able to communicate, in the meeting of the Accademia dei Lincei of December 1954 in Rome, that a new chapter had been disclosed in the field of macromolecular chemistry, due to the discovery of processes to obtain polymers with an extraordinary regularity in their structure in terms of both chemical constitution and configuration of the successive monomeric units along the chain of each macromolecule. 

The reactions of hydrocarbons with [LnO]+ and [ AcO]+ (where Ln = Ce and Nd and Ac = Th and U) have been compared (101) and indicate that the [AcO]+ ions are more reactive than the [LnO]+ ions. In the ions [LnO]+, the metals are in their stable oxidation state but are coordinately unsaturated. None of the [MO]+ ions react with H2, saturated hydrocarbons, ethene, propene, or benzene but they all react with 1,4-cyclohexadiene. The [AcO]+ ions gave benzene addition product ions AcOC6H6]+ as the sole product, whereas the [LnO]+ ions gave the cyclohexadiene and benzene addition product ions, [LnOC6H8]+ and [LnOC6H6]+. 

A more recent raw material for plasticizer alcohols is crack-C4 as a byproduct of steamcrackers in ethene/propene production. After extraction of butadiene for use and etherification of isobutene with methanol to methyl-tertiary-butylether MTBE as an octane enhancer, a stream is left containing 1-butene, 2-butene, and butanes, so-called raffinate II. Oligomerization of the butenes yields C8 olefin mixtures ( dibutene ) as the main product and the corresponding C12 olefins as the main byproduct (tributene). They are the... 

Another application of an isomerisation reaction can be found in the production of the third monomer that is used in the production of EPDM rubber, an elastomeric polymerisation product of Ethene, Propene and a Diene using vanadium chloride catalysts. The starting diene is made from vinylnorbomene via an isomerisation reaction using a titanium catalyst. The titanium catalyst is made from tetravalent salts and main group hydride reagents, according to patent literature. 

Industrially this diene is made the same way as ethylidenenorbomene from butadiene and ethene, but now isomerisation to 2,4-hexadiene should be prevented as the polymerisation should concern the terminal alkene only. In both systems nickel or titanium hydride species react with the more reactive diene first, then undergo ethene insertion followed by (3-hydride elimination. Both diene products are useful as the diene component in EPDM rubbers (ethene, propene, diene). The nickel hydride chemistry with butadiene represents one of the early examples of organometallic reactions studied in great detail [22] (Figure 9.14). 

So far we have only discussed catalysts based on diphosphine ligands with a focus on ethene. We should mention that the ligands that are most effective for this reaction are also capable of making terpolymers of ethene, propene and CO. This is important because the commercially interesting polymers must contain a few percent of propene in order to lower the melting point to around... 

Olefins (alkenes contain double bonds) =c/ / C2H4,C3H6,C4H8,...,C H2 Ethene, propene, butane (ethylene, propylene, butylene) Diolefins contain two double bonds The compounds are unsaturated since C H2 can be saturated to C H2 +2... 

Hexane ethene > propene > butene > methane a pentene > ethane... 

Propane disappears well before the end of the reaction zone to form as major intermediates ethene, propene, and methane in magnitudes that the /3-scission rule and the type and number of C—H bonds would have predicted. Likewise, owing to the greater availability of OH radicals after the fuel disappearance, the C02 concentration begins to rise sharply as the fuel concentration decays. 

A study of the regioselectivity of the 1,3-dipolar cycloaddition of aliphatic nitrile oxides with cinnamic acid esters has been published. AMI MO studies on the gas-phase 1,3-dipolar cycloaddition of 1,2,4-triazepine and formonitrile oxide show that the mechanism leading to the most stable adduct is concerted. An ab initio study of the regiochemistry of 1,3-dipolar cycloadditions of diazomethane and formonitrile oxide with ethene, propene, and methyl vinyl ether has been presented. The 1,3-dipolar cycloaddition of mesitonitrile oxide with 4,7-phenanthroline yields both mono-and bis-adducts. Alkynyl(phenyl)iodonium triflates undergo 2 - - 3-cycloaddition with ethyl diazoacetate, Ai-f-butyl-a-phenyl nitrone and f-butyl nitrile oxide to produce substituted pyrroles, dihydroisoxazoles, and isoxazoles respectively." 2/3-Vinyl-franwoctahydro-l,3-benzoxazine (43) undergoes 1,3-dipolar cycloaddition with nitrile oxides with high diastereoselectivity (90% de) (Scheme IS)." " ... 

The water-soluble palladium complex prepared from [Pd(MeCN)4](Bp4)2 and tetrasulfonated DPPP (34, n=3, m=0) catalyzed the copolymerization of CO and ethene in neutral aqueous solutions with much lower activity [21 g copolymer (g Pd) h ] [53] than the organosoluble analogue in methanol. Addition of strong Brpnsted acids with weakly coordinating anions substantially accelerated the reaction, and with a catalyst obtained from the same ligand and from [Pd(OTs)2(MeCN)2] but in the presence of p-toluenesulfonic acid (TsOH) 4 kg copolymer was produced per g Pd in one hour [54-56] (Scheme 7.16). Other tetrasulfonated diphosphines (34, n=2, 4 or 5, m=0) were also tried in place of the DPPP derivative, but only the sulfonated DPPB (n=4) gave a catalyst with considerably higher activity [56], Albeit with lower productivity, these Pd-complexes also catalyze the CO/ethene/propene terpolymerization. 

AEPDS acrylonitrile-(ethene-propene-diene)-styrene ... 

Recently, alkylation of alkyl aromatic hydrocarbons such as toluene, ethylbenzene, cumene, and xylenes with ethene, propene, and 1,2-diphenylethene was investigated by Kijenski et al. (245), who used superbasic K-MgO and K-AI2O3 catalysts at low temperature at atmospheric and elevated pressures. The reaction kinetics, EPR measurements of adsorbed intermediates, and the effects of poisoning determined by the radical trap TEMPO (2,2,6,6-tetramethyl-l-piperidinyloxyl, free radical) led the authors to conclude that sites are the catalytically active centers. To demonstrate the importance of strong one-electron donor sites (F ) for the alkylation and the inactivity of strong two-electron donor centers, the ethylation of cumene, ethylbenzene, and toluene was carried out with MgO-10%NaOH. On this catalyst, strong basic two-electron donor sites (27 33) were found, along... 

Enormous commerical applications flowed from the revolution initiated by Ziegler and Natta. These include high-density and linear low-density polyethylenes (HDPE, LLDE), polypropene, ethene-propene co- and terpolymers, and polymers from 1,3-dienes (Sec. 8-10). The annual United States production of these polymers exceeded 40 billion pounds in 2000 the global production was about 3-3.5 times the U.S. production. Ziegler-Natta chemistry accounts for the production of one-third of all polymers. 

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