Hydrocarbons phenyl group

The effect of a bulky substituent like a phenyl group on the hydrocarbon chain apparently decreases chain flexibiUty sufficiently to allow more intimate alignment between molecules, less free volume, and therefore a high value for Tg. 

Being a hydrocarbon with a solubility parameter of 18.6MPa - it is dissolved by a number of hydrocarbons with similar solubility parameters, such as benzene and toluene. The presence of a benzene ring results in polystyrene having greater reactivity than polyethylene. Characteristic reactions of a phenyl group such as chlorination, hydrogenation, nitration and sulphonation can all be performed with... 

Phenyl group, as hydrocarbon surface species, vibrational spectra, 42 228 Phenylindanyl cation NMR spectra, 42 146 Phenylnaphthalene, cyclization, 28 318 2-Phenylpentane cyclization, 28 299 isomerization, 30 67-68 reactions on different catalysts, 28 296,301 Phillips catalyst, 31 29... 

There are many other aromatic hydrocarbons, i.e. compounds like benzene, which contain rings of six carbon atoms stabilised by electron delocalisation. For example, if one of the hydrogen atoms in benzene is replaced by a methyl group, then a hydrocarbon called methylbenzene (or toluene) is formed. It has the structural formulae shown. Methylbenzene can be regarded as a substituted alkane. One of the hydrogen atoms in methane has been substituted by a or —group, which is known as a phenyl group. So an alternative name for methylbenzene is phenylmethane. Other examples of aromatic hydrocarbons include naphthalene and anthracene. 

Attempts to detect a thermally populated triplet state ( A ) of 8 by ESR spectroscopy were unsuccessful. This was attributed to the high reactivity of the diradical, which presumably easily abstracts hydrogen atoms in hydrocarbon matrices (to form p-quinodimethane), even at very low temperatures. In this context, the triplet state of /7-phenylenebis(phenylmethylene) has been observed. Apparently, substitution of the carbenic hydrogens of 8 by phenyl groups confers sufficient stability (thermodynamic and perhaps kinetic) to the biradical, which allows its observation. According to variable-temperature ESR spectroscopy, the triplet state of /7-phenylenebis(phenylmethylene) is thermally populated and the singlet state lies 0.5-1 kcal/mol lower in energy [76-79]. 

The constitution of the body formed by removal of the carbinol-chlorine from the halotriphenylmethyl chlorides can hardly be expressed by the formula (C 6H4Hlg)3C. Such a formula would indicate a similar function of the three phenyl groups which, in fact, does not exist. However, the same conclusion can now be drawn regarding triphenylmethyl itself also this hydrocarbon can hardly possess the simple formula (CgHsI C, however satisfactorily this symbol describes all other properties of this strongly unsaturated compound ... 

The results collected in Table 5 suggest that hydrocarbon residues, especially aromatic groups, in the solvent are strongly responsible for the interaction with cis-(1+4). The position of the largest hydrocarbon residue apparently determines whether P- or M-[6]-helicene will be formed in excess. Replacement of the methyl group in (S)-ethyl lactate (b) by a phenyl group giving (S)-ethyl mandelate (d), increases the optical yield fivefold. 

The resistance of polymers to flame may be increased by the addition of halogenated compounds and antimony oxide. Organic phosphate additives inhibit the glow of the char formed in burning polymers. Polymers with chlorine pendant groups, such as PVC, and those with halogen-substituted phenyl groups, such as polyesters produced from tetrabromophthalic anhydride, are more flame-resistant than hydrocarbon polymers. 

The agreement between the physical properties of the pure hydrocarbons and the binary physical mixture is much poorer for these hydrocarbons which contain the aromatic phenyl group than it is for the naphthenic-paraffinic mixtures. The derivatives for the aromatic mixtures are from four to nine times those of the physical mixtures of the pure hydrocarbons where no aromatic rings are present. 

Replacing the hydrogen in 68 with a phenyl group leads to the secondary acetylenic monomer 70. It was believed that this disubstituted acetylene would suppress the reaction of acetylene with itself and insure that there was an acetylene functionality available for reaction with the o-quinodimethane at 200 °G The DSC of 68 showed the presence of a single exothermic peak at 263 °C which the authors felt was adequate evidence for the occurrence of a Diels-Alder reaction between the acetylene and benzocyclobutene. Unfortunately they did not report on any control experiments such as that between diphenylacetylene and simple benzocyclobutene hydrocarbon or a monofunctional benzocyclobutene in order to isolate the low molecular weight cycloaddition product for subsequent characterization. The resulting homopolymer of 68 had a Tg of 274 °C and also had the best thermooxidative stability of all of the acetylenic benzocyclobutenes studied (84% weight retention after 200 h at 343 °C in air). 

Many odd AHs contain even AH fragments on which the NBMO completely vanishes, i.e., the coefficients are zero on both the starred and unstarred sets of atoms. These regions to which the NBMO does not extend are referred to as inactive segments. For the purpose of this review we will describe those odd AHs that contain one or more inactive segments as reducible odd alternant hydrocarbons (ROAH). Examples of ROAH anions are the 3-phenylbenzyl anion (10), which contains an inactive phenyl group (11), and the 2,4(1,8-naphthalenediyl)pentadienyl anion (12), which contains an inactive napthalenediyl group (13). 

Reduction of the hydrocarbon 5,6,11,12-tetraphenyltetracene (rubrene) with a sodium mirror in THF gave a dark green solution from which almost black crystals of the tetrakis-sodium salt 83 could be obtained.1353 Two of the four sodium cations (each doubly solvated by THF) are located (Fig. 53) above and below the central tetracene skeleton and the other two are between pendant phenyl groups. The central sodium ions are 8-coordinate with Na-C 260-263 pm to the phenyl-substituted and 272 pm to the other... 

Substitution of the acetylenic hydrogen atom in 1-ethynylsilatrane by a phenyl group slightly increases the toxicity. The presence of bi- or tricyclic hydrocarbon radicals at the silicon atom leads to a greater increase in toxicity (the LDS0 value for compounds (30) and (41) is 850 and 80 mg/kg, respectively). 

A few of the values were obtained indirectly from correlations with other indicators, because of either insolubility of the betaine in certain solvents or its reaction with them. Thus, the penta-t-butyl-substituted betaine on the five phenyl groups, para to their attachment to the pyridine and the phenoxide groups, is more soluble in aliphatic hydrocarbons than the standard unsubstituted betaine, that is... 

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