Celanese Receives Unconditional Approval from European Commission for Acquisition of Acetex Corporation

Dallas, July 13, 2005: Celanese Corporation (NYSE: CE) confirmed today that the European Commission has unconditionally approved Celanese’s acquisition of Acetex Corporation (Toronto: ATX), clearing the way for completion of the transaction. The transaction, valued at approximately US $492 million (CDN $600 million), has now received all necessary shareholder and regulatory approvals and is expected to close on or about July 20, 2005.

“We are very pleased to receive the European Commission’s approval and to move forward with successfully completing our acquisition of this firstclass manufacturer of acetyl chemicals and specialty polymers,” said David Weidman, chief executive officer and president of Celanese. “Acetex will play a key role in our strategy of increasing the productivity of our acetyls chain of products in order to provide an even more cost-efficient and reliable supply to our customers globally.”

“The acquisition also improves our production capabilities in Europe on key product platforms and provides opportunities for future growth through Acetex’s Saudi Arabian acetyls joint venture. In addition, we expect to achieve substantial synergies in the areas of manufacturing processes, supply chain, sales and administration,” continued David Weidman.

In October 2004, Celanese offered to acquire the approximately 35.4 million fully diluted Acetex shares at a purchase price of CDN $9.00 per share at a cost of CDN $318 million (US $261 million) and to assume Acetex’s CDN $282 million (US $231 million) in debt.

Celanese intends to purchase the outstanding shares out of its cash and will assume the existing debt of Acetex. The company also intends to have Acetex exercise its option to redeem the Acetex 10-7/8% senior notes due 2009 either with cash or, if necessary, Celanese’s existing senior credit facilities. The redemption is expected to take place approximately 30 days from closing. Celanese originally proposed to finance this acquisition entirely through debt.

“Our cash position gives us the flexibility to strategically use cash to return value to shareholders,” said C. J. Nelson, executive vice president and chief financial officer. “By financing the transaction in this manner, we are eliminating the need to increase our debt to the levels we forecasted when we announced the acquisition, and calling the bonds will lower Celanese’s overall cost of borrowed capital.”

In 2004, Acetex had total net sales of approximately US $530 million and employed about 900 people worldwide. Acetex’s operations consist of an acetyls business with plants in Europe and a North-American specialty polymers and film business. The acetyl business includes acetic acid, vinyl acetate monomer and polyvinyl alcohol. These chemicals and their derivatives are used in a wide range of applications in the construction, packaging, automotive, pharmaceutical and textile industries. The specialty polymers developed by Acetex are used to manufacture a variety of plastic products, and Acetex’s films business focuses on products for the agricultural, horticultural and construction industries. Acetex also previously concluded an agreement for a joint venture project to build an acetyls complex in Saudi Arabia and has commenced the technical planning for this facility.

Dallas, Texas. The Company has four major businesses: Chemicals Products, Technical Polymers Ticona, Acetate Products and Performance Products. Celanese has production plants in 12 countries in North America, Europe and Asia. In 2004, Celanese Corporation and its predecessor had combined net sales of $5.1 billion. The presentation of combined net sales of Celanese Corporation with its predecessor is not in accordance with U.S. GAAP. For more information on Celanese Corporation including a reconciliation of the combined net sales, please visit the company’s web site at www.celanese.com.

Forward-looking statements (statements which are not historical facts) in this release are made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. Investors are cautioned that all forward-looking statements involve risks and uncertainties, including those risks and uncertainties detailed in the Company’s filings with the Securities and Exchange Commission, copies of which are available from the Company.