Hydrocarbon structures reactivity

J. Konzelman, Acyclic diene metathesis (ADMET) polymerization. A hydrocarbon structure reactivity study, Ph.D. Dissertation, University of Florida, 1993. 

A Hydrocarbon Structure Reactivity Study. PhD dissertation. University of Florida. 

Most plastics react chemically with chlorine because of their hydrocarbon structural makeup. This reactivity is avoided with some plastics in which fluorine atoms nave been substituted into the hydrocarbon molecule. The Chlorine Institute recommends that hoses constructed with such an inner lining "have a structural layer braid of polyvinyli-dene fluoride (PVDF) monofilament material or a structural braid of Hastelloy C-276. An underlying lesson here is material compatibility. Material compatibility tables exist that engineers can consult, including in other sections within this volume. 

Covering monometallic (Pd, Sn) and multimetallic (Pd-Sn, Pd-Ag) systems, several examples are presented in this chapter to illustrate the possibility offered by this chemistry to control the particle size distribution and the bimetallic interaction at a molecular level. This work is supported by a multitechnique characterization approachusing SnM6ssbauerspectroscopy,X-rayphotoelectron spectroscopy (XPS), low-energy ion spectroscopy (LEIS), and transmission electron microscopy (TEM). Catalytic performances in hydrogenation of different unsaturated hydrocarbons (phenylacetylene, butadiene) are finally discussed in order to establish structure-reactivity relationships. 

If one or more of the hydrogen atoms of a non-metal hydride are replaced formally with another group, R—e.g., alkyl residues—then derived compounds of the type R-XHn-i, R-XHn-2-R, etc., are obtained. In this way, alcohols (R-OH) and ethers (R-O-R) are derived from water (H2O) primary amines (R-NH2), secondary amines (R-NH-R) and tertiary amines (R-N-R R") amines are obtained from ammonia (NH3) and thiols (R-SH) and thioethers (R-S-R ) arise from hydrogen sulfide (H2S). Polar groups such as -OH and -NH2 are found as substituents in many organic compounds. As such groups are much more reactive than the hydrocarbon structures to which they are attached, they are referred to as functional groups. 

There still remains to be accomplished a more careiul correlation of the chemical properties with structure a study of the relative rates of reactivity for the hydrogen atoms on different parts of the hydrocarbon structure and the effects which these differences impose upon the velocity of combustion. 

The mechanistic aspects of aromatic121 and alkene122 radical cation reactions have been reviewed. A second review article covers the structure and properties of hydrocarbon radical cations, as revealed by low-temperature ESR and IR spectroscopy.123 A review of the reactivity of divalent phosphorus radical cations has appeared which discusses ionic and SET processes and their kinetics.124 The structure and reactivity of distonic radical cations have been reviewed, including experimental and calculated heats of formation, structures, reactivity, and mechanisms.122125... 

Fluorinated radicals have played a significant role in the history and development of the field of free radical chemistry, and it was recognized quite early that they have natures which are quite different from those of their hydrocarbon counterparts. As a result, there has been much effort directed towards defining and understanding these differences with respect to their structure, reactivity and chemistry. 

As shown in Scheme 1 (17,19,21), rapid catalytic addition of to I produces Ilia and Illb. The presence of Ilia and the absence of Illb in the products is at least qualitatively consistent with the fact that the former is kinetically favored while the latter is thermodynamically favored (17,19,21). Structure-reactivity relationships provide a preference for hy-drogenolysis of the N-C(2) bond rather than the C(8a)-N bond in Ilia producing V rather than 3-phenylpropylamine. Both Ilia and Illb are converted to decahydroquinoline (VI), mass 139 the rate constant for the latter conversion is significantly greater than the one for the former (17,19,21). The absence of significant amounts of VI in the products is consistent with its facile conversion to hydrocarbons and NH (17,19,21,35). 

The compositional data for 3-ring azaaromatic hydrocarbons appear to be consistent with the network for hydrodenitro-genation of acridine (36) and, based upon considerations of structure-reactivity, our proposed extension of it to other C HgN isomers. 

The development of modem chemistry in the past thirty years dearly demonstrates that oil and natural gas are the ideal raw materials for the synthesis of most mass-consumption chemicals. In addition to the fact that they have been and still are very widely available, they are formed espedally in the case of oil, of a wide variety of compounds providing access to a multitude of possible hydrocarbon structures. The biological and physicochemical processes that contributed to their formation have furnished, apart from a certain quantity of aromatic hydrocarbons, a large proportion of saturated hydrocarbons (paraffins and naphthenes). In fact, these compounds generally display low reactivity, so that it is not easy to obtain the desired finished products. This is why the production of these derivatives entails a sequence of chemical operations which, in practice, require the combination of the facilities in which they take place within giant petrochemical complexes. 

Lastly, the single-events theory, which was historically designed for the activation of carbon-carbon bonds, does not currently cover the reactivity of C-S and C-N bonds. Some computer models have been produced to represent the possible presence of hetero atoms in hydrocarbon structures. Avenues are therefore open for a very wide field of application, that of HDT reactions and sulphide catalysis. They must nevertheless be based on an in-depth, improved description of the heterolytic mechanisms, also studied (Blanchin et al., 2001) under IFP supervision. 

---