Airgas has asked a Delaware judge to let a federal court in Pennsylvania be the first to decide a conflict-of-interest case against a law firm representing Air Products. The request is the latest act in a quickly unfolding drama between Airgas and Air Products, which bid $5.1 billion for its smaller rival earlier this month.

Airgas has accused the law firm, Cravath, Swaine & Moore LLP, of conflict of interest, saying it represented Airgas from 2001 until last October, when it dropped Airgas like a "hot potato" to work for Air Products.

Cravath "is in possession of material, nonpublic information and has betrayed its longtime client," Radnor, Pennsylvania-based Airgas said in a statement. A spokesperson for Allentown, Pa.-based Air Products declined to comment.

A spokesperson for New York-based Cravath said the suit is "without merit" and declined further comment.

The original conflict-of-interest case was set to be heard in a Pennsylvania state court on Tuesday, but Air Products and Cravath were able to move the case to a federal court in Philadelphia.

Then on Monday, Air Products and Cravath filed with a Delaware court to hear the case, prompting Airgas's request to Chancellor William Chandler III to let the matter play out in a Pennsylvania courtroom first.