Carbon structural classification

In summary, we will review carbon black classifications and their properties in rubber. The three most important properties are particle size, structure, and surface area. We will discuss only the tread grades. All of the tread grades of carbon black fall within the range of 20 nm. to 40 nm. 

Classification of organic compounds in terms of their skeletal carbon structure... 

Hydrocarbons are classified by whether their carbon structure includes rings, multiple bonds, or branches. Classification of hydrocarbon structural families is shown here with the chemical formula. Structures are shown as Kekule (also called line-bond) and skeletal structures. 

The classifications in Table 16-3 are intended only as a rough guide. For example, a carbon molecular sieve is truly amorphous but has been manufactured to have certain structural, rate-selective properties. Similarly, the extent of hydrophobicity of an activated carbon will depend on its ash content and its level of surface oxidation. 

In Chapter 10 of Part A, the mechanistic classification of 1,3-dipolar cycloadditions as concerted cycloadditions was developed. Dipolar cycloaddition reactions are useful both for syntheses of heterocyclic compounds and for carbon-carbon bond formation. Table 6.2 lists some of the types of molecules that are capable of dipolar cycloaddition. These molecules, which are called 1,3-dipoles, have it electron systems that are isoelectronic with allyl or propargyl anions, consisting of two filled and one empty orbital. Each molecule has at least one charge-separated resonance structure with opposite charges in a 1,3-relationship, and it is this structural feature that leads to the name 1,3-dipolar cycloadditions for this class of reactions.136... 

The classification fragmentation applies to reactions in which a carbon-carbon bond is broken. One structural feature that permits fragmentation to occur readily is the presence of a carbon that can accommodate carbocationic character (3 to a developing electron deficiency. This type of reaction, known as the Grob fragmentation, occurs particularly readily when the y-atom is a heteroatom, such as nitrogen or oxygen, that has an unshared electron pair that can stabilize the new cationic center.96... 

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