Similarly, pentane, C 5 H 12, and hexane, C6H14, may exist in three and five theoretically isomeric forms respectively; confirmation of this theory is supplied by the fact that all these compounds have been obtained, but no more.
When sodio-malonic ester is condensed with trimethylene bromide the chief product is ethyl pentane tetracarboxylate, tetramethylene dicarboxylic ester being also formed, and from this the free acid may be obtained on hydrolysis.
Both can be formed in cracking pentane or higher alkanes in which various isomers of C 5 H 10 would be formed.
I have put models of the chain isomers of pentane here.
The aim of this study was to validate a gas chromatography (GC) method for measurement of breath pentane in the horse.