Univar N.V., a world leader in chemical distribution, today announced that its U.S. subsidiary, Univar USA, has entered into an agreement to acquire 100 percent of the shares of Chemcentral Corporation for approximately $600 million in cash, including assumed debt.      Chemcentral, established in 1926, is a privately held company headquartered near Chicago, IL. Based on 2006 consolidated revenues of $1.4 billion and EBITDA of approximately $70 million, the company is one of the leading indus...