I would like to file a UCC lien on someone's business property under a promissory note that i have signed by the other party. The problem is that there is no security agreement. If i file a UCC1 lien on the debtors business assets, what would be the harm in doing so? I read the Article 9 statute and is says "business slander". How actionable is that?

You dont technically need a separate security agreement. Rather, you need language in the note that the maker of the note is offering something as security for you taking on the debt.

The term slander of title is somewhat of a misnomer as slander refers to that which is spoken yet the tort slander of title requires publication. A more accurate term would be "disparagement of title".

Check your state statute for elements necessary to prove such disparagement and what the maker is entitled too (e.g. attorney fees).