Attorneys for Dow Chemical have asked a Delaware judge to disqualify an opposing law firm in a dispute over whether Dow should be forced to complete a proposed $15 billion buyout of specialty chemical maker Rohm & Haas.

Dow attorney David Bernick argued Wednesday that the law firm of Wachtell, Lipton, Rosen and Katz has an ethical conflict in representing Rohm & Haas because it has advised Dow in the past on key strategic issues and has a continuing relationship with the Michigan-based chemical giant.

But Wachtell attorney Marc Wolinsky said Dow cannot prove a continuing relationship with his law firm, and that any confidential information it might have received from Dow in the past would not give Philadelphia-based Rohm & Haas a material advantage in the current litigation.

Wolinsky also said Dow has known since June 2008 that Wachtell Lipton was representing Rohm & Haas, and that Dow has waited too long to object.

Chancellor William Chandler III told attorneys that we would rule on the motion for disqualification by the close of business Wednesday.

Dow has said that it cannot complete the buyout as planned because of global economic conditions and the decision by a state-owned Kuwaiti petrochemical firm to pull out of a joint venture that would have provided Dow with several billion dollars, some of which would have been used to acquire Rohm & Haas.

A trial to determine whether Dow should be forced to complete the acquisition using a bridge loan or other financing scheme is set to begin March 9.