West German Chancellor Helmut Kohl today rejected claims that he was involved in arranging illegal donations to the Christian Democratic Union during his tenure as party chairman and premier in his home state of Rhineland-Palatinate.

Displaying flashes of anger and impatience, Kohl testified at a corruption inquiry in the state parliament in Mainz that he had no knowledge of a multimillion dollar tax evasion scheme in which business firms avoided taxes on political donations by laundering funds through charity front organizations.

During a 2 1/2-hour interrogation, Kohl repeatedly insisted that he could not recall contacts with managers of several companies who acknowledged in written notes that they consulted Kohl on methods of payment at various times during the past two decades.

The state parliament is scrutinizing allegations that the Christian Democrats received more than $73 million in illegal donations between 1969 and 1980. Kohl served as party chairman from 1966 to 1973 and as state premier from 1969 to 1976.

The Mainz inquiry is distinct from separate national investigations into illegal party financing and the so-called "Flick affair," in which senior politicians have been accused of taking bribes from the giant Flick industrial concern in return for favorable tax legislation. Former economics minister Otto Lambsdorff is due to go on trial later this month on corruption charges arising from the Flick scandal.

Kohl, who appeared tense and nervous at the start of today's hearing, rebuffed persistent questioning from opposition Social Democrats and denied any memory of conversations allegedly held with business executives regarding political contributions.

"This is an absolute imposition, and you are taking up my time," the chancellor declared at one point during the interrogation. "You are trying to construct connections where evidence for them simply does not exist."

Kohl said all major political parties had "sinned" by honoring the wishes of certain donors to remain anonymous. He contended that he was never aware that charity fronts were used to collect political donations.

The chancellor stressed that he always sought to distinguish between his government and party roles. He said he dropped any involvement in organizing party funds once he became state premier. But later, he admitted that a request for party donations, written on the state premier's stationery shortly after his election in 1969, was "certainly not in order."

Incensed over the continuing charges that his center-right ruling coalition has been tainted by scandals, Kohl accused elements of the German media of waging "cesspool journalism" and said they were seeking to "politically criminalize" legitimate efforts to finance democratic parties.

Despite the lingering controversy over corruption charges, Kohl and his party do not appear to have suffered significant political damage from the party financing probes, according to many commentators. The evidence gathered by the state committee does not appear sufficient to implicate Kohl directly in the allege tax fraud, and it does not seem likely that he will be charged with committing any illegal actions, they note.