only substantial deleterious changes observed in extended tests under these conditions are those caused by polymerization of the vinyl group it is thought that the reason for this unusual lack of reaction and corrosion of the metal surface is the formation of a protective film of some kind experiments wherein previous contact with a vinylbenzyl chloride appears to delay reaction when the metal surface is subsequently contacted with the reactive benzyl chloride seem to support this theory similarly mixtures of benzyl chloride with substantial proportions of a vinylbenzyl chloride fail to react with aluminum the unreactivity of the defined vinylbenzyl chlorides with aluminum is particularly surprising in view of the fact that other closely related chlorides react vigorously even at lower temperatures such reactive chlorides include benzyl chloride ethylbenzyl chloride and 1 and 2 chlorovinyl toluene mixtures such as styrene plus benzyl chloride and vinyltoluene plus benzyl chloride are also reactive showing that a vinyl group per se is not an inhibitor to the reaction of benzyl chloride with aluminum the term aluminum is used herein except where the distinction is made clear to mean both essentially pure aluminum and alloys of at least 90 by weight aluminum content many such alloys are in commercial use and the alloying metals are typically one or more of the elements si fe cu mn mg cr zn and ti less commonly used elements include ni bi pb be v zr and b liquid.