With ChemConnect Inc.'s purchase last week of rival electronic trading exchange CheMatch, more than $4 billion of trades this year in the chemicals and plastics industries may take place over a single E-marketplace. ChemConnect CEO John Robinson will take the top job at the company, which will retain the name ChemConnect. Its joint capabilities will let it attract more buyers and become profitable by year's end, he predicts. ChemConnect, which will move from San Francisco to Houston, CheMatch's headquarters, expects to pick up some trading business from Enron Online, which offered chemicals and plastics trading just before its downfall. "With this merger and the demise of Enron, we're positioned as the major platform," Robinson says. The company expects the deal, a stock-for-stock transaction of an undisclosed amount, to pass shareholder and regulatory muster by next month.