Exhibit 10.46

         
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  Corporate Headquarters
7 Commerce Drive
Danbury, Connecticut 06810   800.766.2681 Telephone
512.794.1100 Direct
512.792.8040 Facsimile
www.atmi.com

December 13, 2010
BY CERTIFIED MAIL
RETURN RECEIPT REQUESTED
M&M Realty and Commerce Park Management Company
PO Box 581
7 Finance Drive
Danbury, CT 06810

c/o:  
Melvyn J. Powers of Commerce Park Management Company, its Manager and President,
on behalf of Commerce Park Realty, LLC (the “Lessor”) regarding the Lease for 7
Commerce Drive, Danbury, CT 06810 between Lessor and Advanced Technology
Materials, Inc. (the “Lessee”)

References:  
The Agreement of Lease dated December 23, 1994 between Melvyn J. Powers and Mary
P. Powers, d/b/a M&M Realty, as original Lessor, and Lessee, as lessee (the
“Original Lease”), as amended by (i) First Addendum to Lease dated January 27,
1995 (the “First Addendum”), (ii) Second Addendum to Lease dated February 24,
1995 (the “Second Addendum”), (iii) First Amendment to Agreement of Lease
between Lessor and Lessee dated as of November 22, 2000 (the “First Amendment”),
(iv) Second Amendment to Agreement of Lease between Lessor and Lessee dated as
of March 24, 2003 (the “Second Amendment”), (v) the Third Amendment to Agreement
of Lease between Lessor and Lessee dated as of January 18, 2007 (the “Third
Amendment”), and (vi) the Fourth Amendment to Agreement of Lease between Lessor
and Lessee dated as of October 30, 2008 (the “Fourth Amendment”); collectively
with the Original Lease, the First Addendum, the Second Addendum, the First
Amendment, the Second Amendment, the Third Amendment and the Fourth Amendment
referred to herein as the “Lease”).

Subject: Notice to Lessor of Lessee’s exercise of the First Renewal Term
Dear Mr. Powers:
In accordance with the terms of the Lease, this document serves as notice of
Lessee’s exercise of the First Renewal Term for the period effective January 1,
2012 until December 31, 2016.
Sincerely,
/s/ Paul Hohlstein
Paul Hohlstein
Sr. Vice President
Supply Chain and Operations

cc:  
Mr. Tim Carlson — Executive Vice President and Chief Financial Officer, ATMI via
email
Randy Green — Director Global Facilities & EHS, ATMI via email
Heather Schroder, Assistant Corporate Counsel, ATMI via email
John R. Ward, Esq., Pullman & Comley, 850 Main Street, P.O. Box 7006,
Bridgeport, CT 06601-7006