Complexation aliphatic hydrocarbons

Hydrocarbon Polymers. Figure 10 shows the positive ion spectrum from high density polyethylene (HDPE), (CH2CH2)n. Each cluster of peaks is due to where m = n,..., 2n + 1. For more complex aliphatic hydrocarbon polymers with pendant groups the smooth decrease in intensity of the clusters from C2 is interrupted, and the relative intensities of the ions within each cluster... 

Fluorination of aliphatic hydrocarbons with cobalt trifluoride gives complex mixtures Isobutane (2-methylpropane) fluorinated at 140-200 °C affords a mixture of 30 products of different degrees of fluorination and of isobutane as well as butane skeletons. The tertiary hydrogen is replaced preferentially Products containing 5-10 atoms of fluorine including a small amount of perfluoroisobutane were isolated [10]. 

Nitrosyl chloride reacts with aliphatic hydrocarbons at room temperature under the influence of light to give a complex mixture of substitution products. When the reaction is run on cyclohexane at —25°, however, the pure oxime hydrochloride crystallizes from the reaction mixture with virtually no side products. 

It has been proposed that aromatic solvents, carbon disulfide, and sulfur dioxide form a complex with atomic chlorine and that this substantially modifies both its overall reactivity and the specificity of its reactions.126 For example, in reactions of Cl with aliphatic hydrocarbons, there is a dramatic increase in Ihe specificity for abstraction of tertiary or secondary over primary hydrogens in benzene as opposed to aliphatic solvents. At the same time, the overall rate constant for abstraction is reduced by up to two orders of magnitude in the aromatic solvent.1"6 The exact nature of the complex responsible for this effect, whether a ji-coinplex (24) or a chlorocyclohexadienyl radical (25), is not yet resolved.126- 22... 

The nitration of moderate to high molecular weight alkane substrates results in very complex product mixtures. Consequently, these reactions are only of industrial importance if the mixture of nitroalkane products is separable by distillation. Polynitroalkanes can be observed from the nitration of moderate to high molecular weight alkane substrates with nitrogen dioxide. The nitration of aliphatic hydrocarbons has been the subject of several reviews. 

Polymerization in aliphatic hydrocarbons is considerably slower than in aromatic hydrocarbons because of decreased dissociation of initiator and propagating ion-pair aggregates. The course of reaction in aliphatic hydrocarbons is complex compared to that in aromatic solvents. Initiation is very slow at the start of reaction hut proceeds with autoacceleration as cross- or mixed association of initiator and propagating ion pairs replaces self-association of initiator. Cross-association is weaker and results in an increased concentration of monomeric initiator. This effect may also explain the higher-order dependence of Rj on initiator (typically between and 1-order) in aliphatic solvents, especially for r- and f-butyllithium. Rp is still -order in initiator independent of solvent. 

Tetrakis(triethylphosphine)platinum(0) is extremely air sensitive and readily soluble in saturated aliphatic hydrocarbons. The complex can be stored under dry nitrogen in a freezer (-35°) for several months. The complex readily loses one of the coordinated phosphine molecules to give Pt(PEt3)36 (dissociation constant (K ) in heptane is 3.0 X 10" ). The H NMR spectrum measured in benzene-d6 shows two multiplets at 5 1.56 (CH2) and 1.07 ppm (CH3). Tetrakis-(triethylphosphine)platinum(O) is a strong nucleophile and reacts readily with chlorobenzene and benzonitrile to give a-phenyl complexes PtX(Ph)(PEt3)2 (X = Cl, CN).7 Oxidative addition of EtOH affords [PtH(PEt3)3] +. 

The yellow complex can be stored under nitrogen for months. It is easily dissolved in benzene, ethers, and halogenated hydrocarbons and less easily in aliphatic hydrocarbons. Mp 93-94°. H NMR (TMS, CDC13, 60 MHz) tNCHj... 

The thermally unstable crystalline complex must be stored under nitrogen below -20°. It is easily dissolved in benzene, diethyl ether, or CH2C12 but is only slightly soluble in aliphatic hydrocarbons. IR vco at 2125 (m), 2040 (vs) cm"1 in hexane. 

Some properties of cobaltacyclopentadiene complexes, prepared in this way, are listed in Table II. The crystals are dark brown to orange brown in color and air stable. They can be stored in air. They are soluble in aromatic and polar organic solvents such as chloroform and THF, but not in aliphatic hydrocarbons. Their solutions are moderately stable to air. In general, these cobaltacyclopentadiene complexes are more stable when they contain more electronwithdrawing substituents. 

The complex FeCo2(CO)9(PC6H5) is black in the crystalline state and purple in solution. It is moderately air sensitive. It has a low solubility in aliphatic hydrocarbons and a moderately good solubility in aromatic hydrocarbons. In cyclohexane solution it shows Vco bands at 2101 (vs), 2059 (vs), 2048 (vs), 2039(vs), 1981 (w), 1969(w)cm 1. It has been used for various types of basic metal cluster reactions.16... 

Though most of the oxygen in the atmosphere has been formed by photosynthesis in plants, some is produced by photolysis of water vapour in the vacuum ultraviolet region A <200 nm. Photolysis of N2, NO, N02, NHa, CO, 002 and small aliphatic hydrocarbons (alkanes) set up complex reactions in the upper atmosphere. 

A new approach to develop a molecular mechanism for Fischer-Tropsch catalysis based on the use of [Fe2Co(CN)6] and [Fe(HCN)2]3 precursor complexes has been disclosed.509 The former produced mainly liquid aliphatic hydrocarbons, whereas the latter gave waxy aliphatic products. Results acquired by various techniques were interpreted to imply that chain growth proceeds via the insertion of CO into an established metal-carbon bond, that is, a C, catalytic insertion mechanism is operative. It follows that C2 insertion is an unlikely possibility. 

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