Polymerization of hydrocarbons

CoF is used for the replacement of hydrogen with fluorine in halocarbons (5) for fluorination of xylylalkanes, used in vapor-phase soldering fluxes (6) formation of dibutyl decalins (7) fluorination of alkynes (8) synthesis of unsaturated or partially fluorinated compounds (9—11) and conversion of aromatic compounds to perfluorocycHc compounds (see Fluorine compounds, organic). CoF rarely causes polymerization of hydrocarbons. CoF is also used for the conversion of metal oxides to higher valency metal fluorides, eg, in the assay of uranium ore (12). It is also used in the manufacture of nitrogen fluoride, NF, from ammonia (13). 

Vinyl ethers constitute a third class of monomers which have been cationically polymerized in C02. While fluorinated vinyl ether monomers such as those described in Sect. 2.1.2 can be polymerized homogeneously in C02 because of the high solubility of the resulting amorphous fluoropolymers, the polymerization of hydrocarbon vinyl ethers in C02 results in the formation of C02-insoluble polymers which precipitate from the reaction medium. The work in this area reported to date in the literature includes precipitation polymerizations and does not yet include the use of stabilizing moieties such as those described in the earlier sections on dispersion and emulsion polymerizations (Sect. 3). 

Nitroxyl radicals (AmO ) are known to react rapidly with alkyl radicals and efficiently retard the radical polymerization of hydrocarbons [7]. At the same time, only aromatic nitroxyls are capable of reacting with alkylperoxyl radicals [10,39] and in this case the chain termination in the oxidation of saturated hydrocarbons occurs stoichiometrically. However, in the processes of oxidation of alcohols, alkenes, and primary and secondary aliphatic amines in which the chain reaction involves the HOT, >C(0H)02 , and >C(NHR)02 radicals, possessing the... 

This paper is about a reinterpretation of the cationic polymerizations of hydrocarbons (HC) and of alkyl vinyl ethers (VE) by ionizing radiations in bulk and in solution. It is shown first that for both classes of monomer, M, in bulk ([M] = niB) the propagation is unimolecular and not bimolecular as was believed previously. This view is in accord with the fact that for many systems the conversion, Y, depends rectilinearly on the reaction time up to high Y. The growth reaction is an isomerization of a 7t-complex, P +M, between the growing cation PB+ and the double bond of M. Therefore the polymerizations are of zero order with respect to m, with first-order rate constant k p]. The previously reported second-order rate constants kp+ are related to these by the equation... 

The polymerizations of hydrocarbon monomers by ionizing radiations differ from those of the VE in several respects which have been set out at the end of Section 2.1 now show that the reaction patterns of the hydrocarbons and the ways in which they differ from those of the VE can be explained adequately by my theory. Unfortunately, c is not known for any of these systems, so that no rate-constants can be calculated by the established method, but another method has been devised based on DP information. 

Co-polymerization of hydrocarbon monomers with polar monomers... 

Regarding the co-polymerization of hydrocarbon and polar monomers, late transition metal catalysts have provided the most significant advances to date because of their lower oxophilicity and thus greater functional-group tolerance than early transition metal catalysts, although group 4 metallocene catalysts are known to promote the co-polymer-ization of olefins and non-vinyl polar monomers with masked functional groups. 

Although much work on the development of transition metal catalysts for the co-polymerization of hydrocarbon and polar monomers has been reported (particularly in the patent literature), so far no effective means seems to exist for directly incorporating functionality into a polyolefin chain by using an industrially feasible process. With respect to polar monomer co-polymerization, Jordan et and Boone et al thoroughly investigated ethylene and vinyl... 

Processes for the polymerization of hydrocarbon gases to motor fuel were developed to a commercial level in the early 1930 s. Thermal polymerization plants, employing temperatures of 900° to 1200° F. and pressures of 60 to 3000 pounds per square inch, were developed first, closely followed by catalytic units operating at temperatures of 280° to 475° F. and pressures of 200 to T 200 pounds per square inch. Currently, thermal polymerization finds its greatest application in combination with thermal reforming of naphtha. Catalytic polymerization has proved highly successful, as is indicated by the fact that one company alone has licensed over 150 plants to date. 

Chapter 12 deals with metathesis Chapter 13, with oligomerization and polymerization of hydrocarbons. Each of these fields is of substantial practical significance and treated emphasizing basic chemistry and significant practical applications. Challenges in the new century and possible solutions relevant to hydrocarbon chemistry are discussed in Chapter 14 (Emerging areas and trends). 

Kuran, W., Stereoregulation Mechanism in Coordination Polymerization of Hydrocarbon Monomers. Part I Polymerization of ot-Olefins , Polimery, 39, 570-578 (1997). 

The primary use of TiCl3 is as a catalyst for the polymerization of hydrocarbons (125—129). In particular, the Ziegler-Natta catalysts used to produce stereoregular polymers of several olefins and dienes, eg, polypropylene, are based on CC-TiCl3 and A1(C2H5)3. The mechanism of this reaction has been described (130). Suppliers of titanium trichloride include Akzo America and Phillips Petroleum in the United States, and Mitsubishi in Japan. 

Most polymerizations of cyclic monomers are ionic processes. Coordination catalysts are effective only for some heterocycles (oxirane and its derivatives, lactones). Ziegler-Natta catalysts can only be used for cycloalkene polymerization by metathesis heterocycles act as a catalytic poison. Smooth radical polymerization of hydrocarbon monomers with ring strain is unsuccessful [304], The deep-rooted faith that ring strain represents a major contribution to the driving force in ring opening (polymerization) has to be revised [305, 306]. 

Transfer during polymerization of hydrocarbon monomers and of monomers containing heteroatoms in side chains... 

Gum formation, which is a polymerization of hydrocarbons (especially aromatic compounds) on the catalyst surface, is a deactivation phenomenon that takes place at low temperature. Therefore, an investigation of the appearance of gum on steam reforming catalysts used at prereforming conditions is very relevant. Deactivation by gum formation can proceed several times faster than ordinary sulphur poisoning. 

There is no inherent termination step in organolithium polymerizations of hydrocarbon monomers, and this method of initiation yields living polymers. Living polymerizations are defined as those in which there is no inherent termination reaction (as described in Section 6.3.3 for free-radical polymerizalions) and in which the macrospecies continue to grow as long as monomer is supplied. 

The facts found with pulsed radio frequency discharge that (1) the largest increase in dangling bonds is observed with ethylene and fluorohydrocarbons (e.g., vinyl fluoride and vinylidene fluoride), (2) the dangling bonds in tetrafluoro-ethylene decrease, and (3) dangling bonds in most perfluorocarbons decrease support a significant difference between the plasma polymerization of hydrocarbons and that of perfluorocarbons summarized above. 

RING-OPENING POLYMERIZATION OF HYDROCARBON-BRIDGED [2]METALLOCENOPHANES... 

A. Ring-Opening Polymerization of Hydrocarbon-Bridged [2 Ferrocenophanes... 

Use Making bearing material, catalyst in polymerization of hydrocarbons, analytical reagent. 

Use To trace the flow of petroleum products in pipelines, to measure rate of catalyst circulation in petroleum cracking plants, to study the cracking and polymerization of hydrocarbons with various catalysts, etc. 

NH, NH-, -CN), silicon and olefinic double bonds are more polymerizable while those containing oxygen (e.g. -C=0,-0-,-0H), chlorine, aliphatic hydrocarbon and cyclic hydrocarbons tend to decompose. Brown (13) reported in his studies of a series of vinyl halides that the dihaloethylenes polymerize more rapidly than the corresponding monohalides and that chlorides and bromides polymerize more rapidly than the fluorides. Kobayashi, et. al. (IJ) found that the additons of certain halo-genated compounds to hydrocarbon monomer streams often dramatically increases the polymerization rate. Thus, these halogenated compounds may be considered to act as gas phase catalysts for the plasma polymerization of hydrocarbons. 

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