Specialty chemicals company Ashland on Wednesday said Chairman and Chief Executive James O'Brien will have surgery to fix a perforated colon and be out for two to three months.

The company said he would be available on "a limited basis" until his full return.

Lead director Barry Perry will be interim chairman, while CFO Lamar Chambers and general counsel David Hausrath will assume his executive duties, Ashland said.

Separately, the company said it would repurchase $400 million in shares and that it intends to raise its annual dividend to 70 cents per share from 60 cents per share, beginning with the June 15 dividend payment.