Hydrocarbons, hydrocarbon nitriles methyl groups

Nitriles. Nitriles can be prepared by a number of methods, including ( /) the reaction of alkyl haHdes with alkaH metal cyanides, (2) addition of hydrogen cyanide to a carbon—carbon, carbon—oxygen, or carbon—nitrogen multiple bond, (2) reaction of hydrogen cyanide with a carboxyHc acid over a dehydration catalyst, and (4) ammoxidation of hydrocarbons containing an activated methyl group. For reviews on the preparation of nitriles see references 14 and 15. 

Since hydrocarbon subunits (methyl, methylene and methine groups) are not polarized to a great extent, their nature can be defined by a polar substituent. The high acidity of the a-hydrogen atoms of carbonyl compounds, nitriles, sulfones, and nitroalkanes follows from polarity alternation, the carbon atoms being a donor next to the acceptor substituent. 

In effect, the methyl group and the functionalized carbon center are converted to the nitrile functional group. However, as shown by isotope labeling experiments, ammoxidation of a hydrocarbon having an allylic hydrogen produces a symmetric intermediate wherein the nitrile functional group can be incorporated into either end of the allylic intermediate (see below). Thus, ammoxidation reactions can be divided into three major classes. The first is ammoxidation of a methyl group, effectively, to a nitrile functionality. 

Methyl side chains of aromatic hydrocarbons can be selectively ammox-idized to nitrile groups. The process is very similar to the ammoxidation of propene and the same catalysts are found to be effective. Identical mechanisms have been proposed, and will not be discussed here. 

Melt adhesives and plastisols do not contain solvents. The solution adhesives group includes products made from the following polymer-solvent systems nitrocellulose (typical solvents include solvent combinations usually of a ketone or an ester, an alcohol and a hydrocarbon selected from isopropanol, 2-butylhexanol, amyl acetate, acetone, methyl ethyl ketone), nitrile rubber (main solvent - methyl ethyl ketone), polychloroprene (which is usually dissolved in a mixture of solvents including a ketone or an ester, an aromatic and aliphatic hydrocarbon selected from naphtha, hexane, acetone, methyl ethyl ketone, benzene, toluene), and polyvinyl acetate (water). 

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