The Senate agreed to vote today on the long-stalled nominations of Richard R. Burt and Richard T. McCormack as assistant secretaries of state for European affairs and economic affairs, respectively.

Procedural holds placed on the two nominations by conservative and liberal senators have been withdrawn one by one since Christmas, defusing filibuster threats and, for now, taking the edge off a heated political battle over key foreign policy slots in the Reagan administration.

In announcing the scheduled vote, Senate Majority Leader Howard H. Baker Jr. (R-Tenn.) said yesterday that he would grant the request of Sen. Jeremiah Denton (R-Ala.) to hold a one-hour closed session to receive classified information.

Senate sources said the time will be used as a last-ditch effort by conservative senators to persuade their colleagues that a June, 1979, article written by Burt, then a reporter for The New York Times, seriously compromised a U.S. spy satellite program.

Baker said the closed session would be limited to an hour and that the vote on Burt, who is expected to win confirmation easily, would occur at 2 p.m.

Burt, who joined the administration as director of the Bureau of Politico-Military Affairs, was nominated early last year for the European post. The move drew immediate opposition from conservatives. Liberal senators retaliated by placing a hold on the nomination of McCormack, a former aide to Sen. Jesse Helms (R-N.C.).

Meanwhile, Baker said he expects the nomination of Kenneth Adelman as head of the Arms Control and Disarmament Agency to be voted out by the Senate Foreign Relations Committee and sent to the Senate floor.

Fifty House Democrats issued a statement yesterday opposing Adelman's nomination, saying he has been "scornful of the SALT Strategic Arms Limitations Talks process and of arms control in general."