Methylene prefix

When a CH2 group is doubly bonded to a ring the prefix methylene is added to the name of the nng... 

The parent with the most substituents cited as prefixes (bridging substitution, e.g. 2,3-O-methylene, is regarded as multiple substitution for this purpose). 

Cyclopropane and the cyclic compounds shown in Figure 1-12, cyclopentane and cyclohexane, are members of the alicyclic branch shown in Figure 1-4. The is the same prefix as used in the aliphatics because of the structure. Except for the cyclic formation, they are made up basically of chains of methylene groups (-CH2-). But. one difference from the aliphatic series of.organics is the ch-emical reactivity. Lower members of the alicyclic series have one chemical property similar to double-bonded olefins—they are quick to react chemically. 

Rule 4. Name the side chains by approved radical names and precede these with the correct position numbers. For the acyclics, the complexity order and the alphabetical order of prefixes will be identical, since only methyl and methylene side chains are involved — for example, 2,6-dimethyl in geraniolene (Nos. 1A and IB, Chart 3) and 7-methyl-3-methylene in myrcene (No. 2, Chart 3). 

Methylcyclohexanol, dehydration of, 183 1-Methylcyclopentene addition of hydrogen chloride, 215 hydroboration-oxidation, 230-233 Methylenecyclohexane, 677 Methylene group, 57 prefix, 170... 

End groups are usually not specified in high polymers. End groups, however, can be known parts of the structure. This can be the case with telomers. Here, the end groups are named as radicals, prefixed by Greek letters, a and co. They appear before and after the name of the polymer. The structure of a telomer, C1-(-CH2-)aHCC13, is therefore called of-chloro-cu-trichloromethyl poly (methylene). 

On the other hand, modern nomenclature is based on the chemical structure of the macromolecules. The name of a polymer of unspecified degree of polymerization consists of the prefix poly and the name of the smallest repeating unit. With unbranched polymers, the smallest repeating unit is a diradical. The name of this diradical is the same as that met with in the nomenclature for low-molecular-weight organic diradicals. Thus, the group —CH2— is called methylene and the corresponding polymer is called poly(methylene) (example 1 in Table 1-4). The diradicals —CH2—CH2— and —CH2—CH(CH3)— do not have simple definitive names the trivial names ethylene and propylene are retained. Examples of names for other diradicals are as follows ... 

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