KYIV, Sept 9 (Reuters) - The Ukrainian central bank raised its main interest to 8.5% from 8.0% on Thursday, the fourth rate hike this year, to tackle persistently high inflation. “Tighter monetary policy will help rein in inflation expectations and bring back a steady disinflation trend toward the 5% target, which is projected to be met in 2022,” the National Bank of Ukraine (NBU) said in a statement. The hike is in line with market expectations. A Reuters poll of analysts this week predicted a rate rise. (Reporting by Pavel Polityuk and Matthias Williams; Editing by Jon Boyle)