The Paisley and Renfrewshire South politician said the announcement of the BASF closure in the town was the last thing it needed.
Workers were told the news on Tuesday.
Mr Alexander said: "I am bitterly disappointed by the announcement that the BASF site is to close. It is a hammer blow to the area and the very last thing Paisley needs when we are already facing a jobs crisis.
"For more than four decades, Paisley employees have loyally served at the factory. I have already met with the company and plan to visit the plant this week to discuss the situation with the management and shop stewards."
Mr Alexander added that his immediate concern was for the workforce and their families.