I am sorry, it seems that you were asking a straight question, I do not know you yet so I was not sure if you were fabricating a story in order to sound like you had a legitimate use for formic acid. A lot of newer bees use this tactic and it seems to cause problems when they ask questions.
If my dog had purchased ACS formic acid I wouldn't have to ask this question would I?That is exactly what I mean, I would hope you would not have to ask that question but many newbees in fact do just as you state, purchase reagent grade formic and post some shit about acquiring acid for the sole purpose of controlling mites or some other false usage and want to know how to use it in their reaction. They add a fictional element to the question that t-totally changes the question at hand. After you have been here a while you might understand what I mean.
Read this whole thread,
Post 518871
(skanic: "glycerol separation", Chemicals & Equipment) not to pick on anyone but do you see how things can get out of hand when the original question is not asked correctly in the first place. You obviously had a legit question unfortunately many have been conditioned to think the absolute worst. I had an old boss that told me "I will start off assuming you know nothing, it is up to you to impress me". Well I guess that is what we do here, when you are new you will probably be doubted and be looked at under a fine tooth comb. Don't worry, it will pass. Once bees get to know you, they will better understand your knowledge of the subject, and will not have to assume you know nothing.
Take your original question for example:
My dog found 65% formic acid for varroa mites. Can he use this directly in a performic oxidation of isosafrole as long as he recalculates the necessary volume? Well if I read this as written and assume that you are not well versed in the subject it sounds as if you want to use 65% formic acid in order to oxidize your alkene. Obviously you would have to prepare the peracid first so no you could not directly use formic acid in place of performic acid in a performic oxidation unless you first prepared the perfromic acid. You may or may not know this, we don't know yet. The 65% formic is a fairly low percentage to be using for the preparation of the peracid. I think it has worked for some, however I think many have distilled formic acid in order to "concentrate" it further. I have no experience in this personally but I am sure it is in TFSE.
Also notice the emoticon at the end of this sentence:
Or are you trying to be cute by saying that you purchased 65% formic acid from a chemical supplier, for the purpose of controlling verroa mites, thinking you are somehow duping law enforcement or something. If you ask a straight question, you might get a straight answer. 
I was not condemning you, just trying to get a better feel for who you are and what you are asking.
Well I have been rambling now for a while, maybe you will get something out of my post, maybe you won't. Sorry about doubting you, I am sure you will do fine here.
And please tell me what breed of dog you have that purchases reagents for you...
much_love
methyl_ethyl
