Appeal No. 2004-0495 Paper 22
Application No. 09/503,599 Page 3
transesterification catalyst, including organic and inorganic compounds of titanium,
lanthanum, zinc and cobalt, is mixed with 1,3-propanediol prior to mixing with the
terephthalic acid ester (3:9-28). Still further according to the specification, the
preheated 1,3-propanediol/terephthalic acid ester mixture may be injected into the ester
exchange vessel at or below about the midpoint of the vessel (4:34 - 5:1). For example,
a mixture of preheated, catalyzed 1,3-propanediol and preheated
dimethylterephthalate is injected into the base of the exchanger, and
additional virgin 1,3-propanediol, typically at ambient temperature, is
injected at the quarterpoint of the exchange column. In this embodiment,
the mixture that is injected into the base of the exchanger has a lower
mole ratio of 1,3-propanediol to dimethylterephthalate and a higher
catalyst concentration ..., such that the overall mole ratio and catalyst
concentration remain within the above-described ranges, after taking into
account the additional 1,3-propanediol that is injected at the quarter point.
In still another alternative, preheated dimethylterephthalate and preheated
catalyzed 1,3-propanediol are injected into the exchanger separately
without premixing. For example, the dimethylterephthalate is injected into
the base of the exchanger, and the catalyzed 1,3-propanediol is injected
at the quarterpoint. [Specification, 5:18-31.]
Gaseous reaction products typically include methanol vapor, acrolein and allyl alcohol,
while liquid reaction products include bis(3-hydroxypropyl) terephthalate monomer, low
molecular weight oligomers of 1,3-propanediol and terephthalic acid, and less than 9
wt.% unreacted terephthalic acid ester (id., 6:4-23).
We make reference to appellants' Appeal Brief ("Brief," Paper 19, filed 11 March
2003) and the Examiner's Answer ("Answer," Paper 20, mailed 3 April 2003).
The examiner relies on the following references in his rejection.
Armstrong et al. (Armstrong) 3,534,082 13 October 1970
Kurian et al. (Kurian) 5,840,957 24 November 1998
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