Commerce Secretary Juanita Kreps said today she hoped to conclude a troublesome claims and assets agreement before leaving China May 15 but was less confident of initialing a general trade agreement by then.

At a press conference, she said the Chinese still had questions about several parts of the draft trade agreement, which is four times longer than trade agreements Peking has signed with Japan, France and the Common Market.

A member of the U.S. negotiating team said Peking found it difficult to work out its position on honoring U.S. patents, since it has not had any patent law of its own in 30 years.

Final agreement on a formula to pay for U.S. property seized in China in 1949 and to unfreeze Chinese assets in the United States must precede initialing a trade agreement, Kreps said. Treasury Secretary Michael Blumenthal initialed a claims agreement March 1, but the Chinese have been seeking more U.S. government guarantees of help in moving their asset claims swiftly through American courts.

Commenting on the claims issue, Kreps said, "We are making progress and I am personally remaining hopeful that we will be able to sign the agreement before we leave China." Asked if she would then also initial a trade agreement, Kreps said, "I just dont't know. I think there are probably so many open issues that on balance it would seem unlikely."

A trade agreement would further solidify the growing Sino-American economic ties, which Kreps estimates will total $2 billion in trade this year. If the Chinese sign a trade agreement and agree to limit their textile exports to the United States, President Carter has said he will ask Congress to grant Peking most-favored-nation trading status. This would reduce tariffs on Chines goods and increase Peking's profits.

Kreps said the Chinese have agreed to begin negotiating an aviation agreement. This would take up the complex question of landing rights to allow American airlines to land in China and vice versa CAPTION: Picture, Secretary Kreps, Chinese Minister Fang Yi at signing of technology pact Tuesday. Hsinhua via - UPI