Alkanes with aromatic rings

We classify hydrocarbons according to their bonding (Section 2-12), as shown in Table 3-1. Alkanes have only single bonds. A hydrocarbon with a carbon-carbon double bond (such as ethylene) is an alkene. If a hydrocarbon has a carbon-carbon triple bond (like acetylene), it is an alkyne. Hydrocarbons with aromatic rings (resembling benzene) are called aromatic hydrocarbons. 

The BMT-biiilding blocks primarily used in commercial bismaleimide resins are 4,4 -bismaleimidodiphenylmethane, 2,4-bismaleimidotoluene [6422-83-9] 1,3-bismaleimidobenzene [3006-93-7J, and, sometimes, aUphatic BMIs based on alkanes. However, because of toxicity problems associated with MO A (4,4 -diaminodiphenylmethane) and other diamines with only one or two aromatic rings, polyaromatic diamines and BMIs based on them ate... 

The aromatic hydrocarbons are used mainly as solvents and as feedstock chemicals for chemical processes that produce other valuable chemicals. With regard to cyclical hydrocarbons, the aromatic hydrocarbons are the only compounds discussed. These compounds all have the six-carbon benzene ring as a base, but there are also three-, four-, five-, and seven-carbon rings. These materials will be considered as we examine their occurrence as hazardous materials. After the alkanes, the aromatics are the next most common chemicals shipped and used in commerce. The short-chain olefins (alkenes) such as ethylene and propylene may be shipped in larger quantities because of their use as monomers, but for sheer numbers of different compounds, the aromatics will surpass even the alkanes in number, although not in volume. 

Evidence also suggests, however, that alkanes with only five carbon atoms in a linear chain may undergo aromatization via 1,5 ring closure followed by ring enlargement. Numerous mechanisms were put forward to rationalize these transformations.209... 

As already noted the hybrid bonds of benzene rings have the same stability as the carbon-carbon single bonds found in the alkanes. The aromatic compounds can enter into many reactions which do not affect the ring structure. The volatile aromatics are highly flammable and bum with a luminous, sooty flame in contrast to alkanes and alkenes, which bum with a bluish flame, leaving little carbon residue. 

One aromatic ring causes a deficiency of 8 hydrogen atoms compared to an alkane with the same number of carbon atoms. This explains the term 8 Ra in equation (26). From equation (26) it follows for the molecular weight that... 

Using compounds other than those shown in Figure 13.1, give examples of each of the following kinds of hydrocarbons (1) alkanes, (2) unsaturated nonaromatic hydrocarbons, (3) aromatic hydrocarbons, (4) polycyclic aromatic hydrocarbons with multiple rings, and (5) mixed hydrocarbons. 

Alkanes and Aromatics. The distinction between aromatic and poly-cyclic was arbitrarily set at three conjugated six-member rings in Table I. With this definition the alkanes and aromatic hydrocarbons, with 25 entries, dominate the list of identified components. These compounds are also present in the highest concentration in the different effluents. Ordinarily their concentrations were not measured because of a low interest in these kinds of compounds but in those instances where measurements were made, the amounts ranged from 10-1500 ng/M3 in the vapor phase and from 10-90 ng/g on the suspended particles in the stack effluents. These hydrocarbons were not quantitated for any of the fly and grate ash samples. 

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