DETROIT — Dow Chemical Co. announced Tuesday it is cutting 1,000 jobs, or about 2.3 percent of its work force, as part of a plan to rid itself of underperforming businesses and boost its global efficiency.

The Midland-based company, one of the nation's biggest chemical makers, said it will exit the automotive sealers business within the next nine to 18 months in North America, Asia and Latin America. It will look at options in its European operations.

Other cutbacks include idling a styrene plant in Camacari, Brazil, on Jan. 1 and closing a cellulose manufacturing facility in Aratu, Brazil, in the first quarter of next year.

Wholly owned subsidiary Union Carbide Corp. will shut down its polypropylene facility in St. Charles Parish, La., before the end of the year, and the company will significantly reduce research and development and other functions at a facility in South Charleston, W.Va.

Dow expects the cuts will result in a charge of $500 million to $600 million for write-downs and severance packages in the fourth quarter of 2007. The company said it expects to save $180 million a year once the moves are made.

The company employs about 43,000 people worldwide.