5. Shafer is prior art vis-a-vis applicant under
35 U.S.C. § 102(b).
Shafer
6. Shafer describes a process very similar to that of
applicant's claim 1.
7. With reference to the language of applicant's
claim 1, Shafer describes the following:
A process for purification of diaryl carbonates 3, which
comprises:
[1a] providing [a] a crude solution of diaryl carbonate
in admixture with contaminant by-products 4 of a diaryl
carbonate preparation and [b] sufficient phenol so as to be
able to form a crystalline 1:1 molar diphenyl carbonate to
phenol adduct;5
[2] cooling the solution to a temperature of about
1-2°C below the nucleation temperature 6 of the diaryl
carbonate at a controlled rate, 7 between about 0.01 to 1.0°C
3 Col. 1, lines 12-14: "The present invention relates to a method for
recovering diphenylcarbonate in substantially pure form from a solution of
diphenylcarbonate and phenol." Thus, both applicant and Shafer have as an
ultimate objective recovery of essentially pure diphenyl carbonate.
4 Col. 2, line 1. The diphenyl carbonate would contain contaminants from
its preparation (col. 2, lines 61-63).
5 Col. 1, line 66 to col. 2, line 4.
6 According to Example 1 in the specification, the nucleation
(crystallization) temperature of diphenyl carbonate is 53.8°C
(specification, page 6, line 32). Further according to Example 1, the
crude diphenyl carbonate was cooled to 53°C, which is about "1-2°C" below
the nucleation temperature of diphenyl carbonate.
According to Shafer, adduct crystals form at 51°C. Shafer also
describes cooling to a temperature of 50°C to 25°C, with 50°C being 1°C
below the crystallization temperature of the adduct.
7 Shafer describes lowering the temperature in stages, for example a
first stage at 44.5°C to obtain a certain level of crystallization, followed by
a second stage at 37°C to provide additional level of crystallization (col. 2,
lines 36-53).
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Last modified: November 3, 2007