(Reuters) - Dow Chemical Co (>> The Dow Chemical Company) reported lower-than-expected quarterly results due to weak earnings at its performance materials unit and said it expects to raise $3 billion (1 billion pounds) to $4 billion from asset sales.

Dow Chemical shares fell nearly 4 percent in premarket.

The company is looking to sell its epoxy, commodity chlorine derivatives and European construction materials businesses, which together contribute about $6 billion to annual sales.

Dow Chemical and rival DuPont (>> E I Du Pont De Nemours And Co) are shifting focus to production of seeds and pesticides, where sales have been booming, and are shedding businesses that are more exposed to swings in commodity prices.

The performance materials unit, which makes epoxy, engineered plastics and polyurethane foams, reported a 36 percent fall in third-quarter earnings before interest, taxes, depreciation, and amortization (EBITDA).

"In performance materials, we are still facing significant headwinds and so that's why you see us increasing that divestiture target to $3-$4 billion," spokeswoman Rebecca Bentley said.

"We are taking very aggressive actions within (epoxy as well as portions of the company's chlorine business) right now to improve profitability but we are also stating very clearly that a transaction is likely," she said.

Dow Chemical did not outline a time frame for the new asset sales target.

The largest U.S. chemical maker by sales has divested non-core businesses representing about $8 billion in revenue since 2009.

The company sold its polypropylene licensing and catalyst business to smaller rival W.R. Grace & Co (>> W.R. Grace & Co.) for $500 million this month as a part of its earlier plan to sell non-core assets worth about $1.5 billion by 2014.

AGRI GAINS OVERSHADOWED

Lower earnings at the performance materials unit offset gains in the agriculture and plastics business, leading the company to report lower-than-expected results for the first time this year.

Dow Chemical's net income rose 20 percent to $594 million, or 49 cents per share, also helped by its packaging, coatings and infrastructure and electronics businesses.

Adjusted profit was 50 cents per share, missing the average analyst estimate of 54 cents per share.

Revenue rose 1 percent to $13.73 billion. Analysts on average had expected $13.99 billion.

(Reporting by Garima Goel and Swetha Gopinath in Bangalore; Editing by Kirti Pandey and Saumyadeb Chakrabarty)

By Garima Goel and Swetha Gopinath