The vice chairman of the Chicago Board of Trade has been identified by federal officials as one of the professional grain speculators who allegedly tried to corner the market in wheat.

He also sat in on Board of Trade discussions this week that prevented federal authorities from taking action against feared future market manipulations, Board of Trade officials confirmed yesterday.

The CBOT official, Leslie Rosenthal, and one of his partners face commodity fraud charges in a separate case that could force them out of the business.

The Commodity Futures' Trading Commission has ordered a hearing next month on the earlier fraud charges against Rosenthal and Allen Freeman, a general partner in Rosenthal & Co. of Chicago.

Rosenthal, Freeman and 14 other employes of the firm are accused of making "false and misleading statements" to customers as part of a "nationwide high-pressure sales campaign" in 1977 to sell commodity options.

A year earlier the Commodity Futures Trading Commission obtained an injunction prohibiting Rosenthal, Freeman and others associated with the Rosenthal firm from violating other antifraud provisions of federal commodity laws, CFTC records show.

Neither of the cases involves trading on the Chicago Board, and Rosenthal and Freeman remain members in good standing of the commodity exchange, a spokesman said yesterday. Last year, Rosenthal was elected vice chairman of the CBOT and named to the board of directors, which oversees the world's largest commodity exchange.

In that capacity, exchange officials confirmed, Rosenthal attended a series of meetings in the past two weeks in which the exchange's officers debated what to do about apparent irregularities in trading of wheat futures for March delivery.

Those meetings led the exchange to sue the Commodity Futures Trading Commission, challenging a CFTC order to halt March wheat trading. The Board of Trade won the case in a decision that CFTC officials said could severely limit their power to deal with manipulation of the commodity markets.

Rosenthal "disqualified himself absolutely" from the board's discussions about March wheat trading, but did sit in on the talks, said Robert Wilmouth board president. Wilmouth insisted that Rosenthal "did not attempt to influence the board" and did not vote on a formal resolution dealing with the disruption of wheat futures trading.

CFTC sources pointed out that Rosenthal must have discussed the matter with other board members, because the exchange stated publicly that it was communicating with the major investors in the market.

Rosenthal and Freeman last week refused to return phone call inquiries about their wheat dealings. Yesterday a Rosenthal & Co. employe said the two "are not available for comment."

Rosenthal's role in the March wheat case crisis is a major concern of some CFTC regulators, who are trying for the first time to exert federal control over a market that has traditionally regulated itself.

The potential conflict of interest of an exchange officer who must make decisions that affect millions of dollars of his investments also troubles some commodity market observers.

The CFTC in December issued a warning to Rosenthal and Freeman about their unusually large holdings in wheat for delivery in December, court records in the law suit revealed.

When a similar concentration of contracts for wheat occurred last week, Rosenthal and Freeman were again involved, CFTC sources said. Four grain speculators controlled 90 percent of the wheat market, the CFTC said, and Freeman alone held contracts for 2.5 million bushels of wheat, more than the entire supply in Chicago.

With a shortage of wheat to fulfill their contracts the two potentially could have made windfall profits by temporarily forcing up the price, CFTC officials said.

The price did not rise, however, because the CFTC and the Board of Trade stepped in. Because of that action, no criminal charges are expected to be filed in the matter, CFTC sources said.