<PAGE>

                                                                 EXHIBIT 31(b)

                  CERTIFICATION OF CHIEF FINANCIAL OFFICER
                           PURSUANT TO SECTION 302
                      OF THE SARBANES-OXLEY ACT OF 2002

I, James M. Sullivan, certify that:

1. I have reviewed this Quarterly Report on Form 10-Q of Solutia Inc.;

2. Based on my knowledge, this report does not contain any untrue statement
of a material fact or omit to state a material fact necessary to make the
statements made, in light of the circumstances under which such statements
were made, not misleading with respect to the period covered by this report;

3. Based on my knowledge, the financial statements, and other financial
information included in this report, fairly present in all material respects
the financial condition, results of operations and cash flows of the
registrant as of, and for, the periods presented in this report;

4. The registrant's other certifying officer and I are responsible for
establishing and maintaining disclosure controls and procedures (as defined
in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over
financial reporting (as defined in Exchange Act Rules 13a-15(f) and
15d-15(f)) for the registrant and have:

           a) Designed such disclosure controls and procedures, or caused
           such disclosure controls and procedures to be designed under our
           supervision, to ensure that material information relating to the
           registrant, including its consolidated subsidiaries, is made
           known to us by others within those entities, particularly during
           the period in which this report is being prepared;

           b) Designed such internal control over financial reporting, or
           caused such internal control over financial reporting to be
           designed under our supervision, to provide reasonable assurance
           regarding the reliability of financial reporting and the
           preparation of financial statements for external purposes in
           accordance with generally accepted accounting principles;

           c) Evaluated the effectiveness of the registrant's disclosure
           controls and procedures and presented in this report our
           conclusions about the effectiveness of the disclosure controls
           and procedures, as of the end of the period covered by this
           report based on such evaluation; and

           d) Disclosed in this report any change in the registrant's
           internal control over financial reporting that occurred during
           the registrant's most recent fiscal quarter (the registrant's
           fourth fiscal quarter in the case of an annual report) that has
           materially affected or is reasonably likely to materially affect,
           the registrant's internal control over financial reporting; and

5. The registrant's other certifying officer and I have disclosed, based on
our most recent evaluation of internal control over financial reporting, to
the registrant's auditors and the audit committee of registrant's board of
directors (or persons performing the equivalent functions):

           a) All significant deficiencies and material weaknesses in the
           design or operation of internal control over financial reporting
           which are reasonably likely to adversely affect the registrant's
           ability to record, process, summarize and report financial
           information; and

           b) Any fraud, whether or not material, that involves management
           or other employees who have a significant role in the
           registrant's internal control over financial reporting.

Dated: May 1, 2006

                                           /s/ James M. Sullivan
                                           ---------------------
                                           James M. Sullivan
                                           Senior Vice President
                                           and Chief Financial Officer