Isomerizing butane into isobutene

Factual Questions
1

Can somoeone give me a quick and dirty explanation (one that a tax lawyer can understand) of what it means to isomerize butane into isobutene?

I know that when processing certain olefins (I think propane into propylene), the basic thing happening is that an oxygen molecule is being added to the propane. Is something similar to that occurring here?

For my purposes, there’s a difference between (1) refining a “mineral or natural resource” (i.e., removing impurities, or separating a mineral or natural resource into different things) and (2) processing beyond the refining stage (i.e., turning a refined product into a new product). So I’m trying to figure out which category the isomerization of butane into isobutene falls into, and I’m pretty sure it’s the second one.

Thanks.

2

OK, google (and a book I found in our library) was my friend, so here’s what I’ve got. I’d appreciate any correction from one of you chem e types:

(the numbers are subscripts, obviously, but I don’t wanna do all the coding)

Thanks.