The directors of the new U.S. Synthetic Fuels Corp. have begun a study of how much to pay the chairman and top officers of the organization, who will be responsible for spending as much as $88 billion over the next 12 years to promote synfuels production.

The top-ranking officials may receive $100,000 a year or more if the Synthetic Fuels Corp. follows the pattern of similar organizations here.

That is what the board of the new corporation appears to have in mind. At its first meeting Oct. 8, chairman John C. Sawhill and other board members agreed that the maximum available federal salary for top staff members might be too low to attract experts from energy companies and financial institutions. That top federal salary is $69,630, the amount members of the president's cabinet receive.

Sawhill, whose salary is also still to be determined, suggested that the board ask an outside consultant to propose a schedule of salaries and benefits for the organization's top staff. In addition to Sawhill, the chairman and chief officer, the corporation will have eight division leaders under its current makeup.

On Monday the board meets again to choose the consultant. The study is expected to take six weeks.

The consultant is likely to look at organizations like Comsat, the communications satellite agency; Conrail, the federally chartered private rail service, and the Federal National Mortgage Association in suggesting comparative salaries for the top Synthetic Fuels Corp. officers, said David Wimer, managing partner here of Hay Associates, the leading consulting firm on compensation questions.

And that is six-figure territory.

David O. Maxwell, the incoming chairman of the Federal National Mortgage Association will be paid $225,000 when he takes office Feb. 1. Maxwell, 50, is the chairman of Ticor Mortgage Insurance Co., and a former general counsel of the Department of Housing and Urban Development.

Dr. Joseph Charyk, who has been president of Comsat since 1963, receives $200,000 annually, the same figure as the president.

Edward C. Jordan, chairman of Conrail, receives $305,000 a year.

"They all are different jobs. They pay a little differently," said Wimer.

What a consultant will do is look at the authority and responsibility that Sawhill and his top aides will have, and compare that with comparable positions in private industry and the federal government, he said.

The top officials of the new corporation will have to have experience in energy production and financial management, Wimer said, and such people aren't cheap. "The compensation for the top financial jobs varies all over the place, from $70,000 a year to five and six times that," he said.

The consultant's recommendations must be approved by the board, which consists of Sawhill; Catherine Cleary, former chairman of First Wisconsin Trust Co.; John DeButts, retired chairman of American Telephone and Telegraph Co.; Lane Kirkland, president of the AFL-CIO, and Frank Savage, vice president and manager of the investment management department of Equitable Life Insurance Co.

The board's recommendations, in turn, go to President Carter for final approval.