Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phenol – phenol ether – or inorganic phenolate
Reexamination Certificate
1999-09-20
2001-10-23
Boykin, Terressa M. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From phenol, phenol ether, or inorganic phenolate
Reexamination Certificate
active
06307004
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to parallel reactions.
2. Discussion of Related Art
Traditionally, investigating the efficacy of catalysts and optimizing reaction conditions for melt polymerizations has been carried out one reaction at a time with the resulting polymer analyzed upon completion of the polymerization. The scale of these reactions has generally ranged from several grams to several hundred grams and, thus, stirring is required for good heat transfer, for distribution of small amounts of catalyst, and to renew surfaces in those reactions that required loss of a volatile by-product to drive the reaction to completion. In addition, due to mass transport limitations in thick samples, reduced pressures in the headspace over the reaction are typically used to facilitate removal of by-products from the reaction. Furthermore, traditional prior art parallel polymerizations are generally carried out for biochemical reaction mixtures at temperatures well below 100° C.
In U.S. Pat. No. 5,609,826, Cargill et al. refer to a reaction block that uses replaceable reaction chambers supported in the block. Each reaction block is fitted with four sets of 12 reaction chambers, and has fittings that facilitate robotic manipulation. The reaction chambers are fitted with a frit. An s-shaped trap tube snaps into a fitting on the bottom of each reaction chamber. The trap tube runs into a drain tube. The reaction block is preferably fitted with gas (preferably N
2
) lines and a septum seal such that gas pressurization empties the reaction chambers into the drain tubes. The drain tubes are arranged to mate directly with a standard 96 well microtiter plate for the collection of material. A docking station provides for secure registration of the reaction blocks, and provides for introduction of gases and liquids into the reaction blocks. An inert atmosphere in the reaction block is maintained by a top and (optional) bottom seal. A synthesis support may be introduced into each reaction chamber as a slurry, and the top septum fastened. A needle pipettes reagents from an array of reagent containers into the reaction chambers, and maintains the inert atmosphere. A locking reagent container rack keeps the containers securely in place.
As the demand for high performance materials has continued to grow, new and improved methods of providing improved products more economically are needed to supply the market. Due in part to the advantages inherent in polymer production by the melt process, there is significant interest among industry members in producing polymers with low Fries product content. In this context, various reactant and catalyst combinations for melt polymerization are constantly being evaluated; however, the identities of chemically or economically superior reactant systems for melt polymerization processes continue to elude the industry. As parallel screening gains popularity in all areas of chemistry, high-throughput screening of potential reactant systems will become increasingly important. As such, new and improved methods are needed for rapid production and quantification of reaction products.
SUMMARY
Accordingly, the present invention is directed to an elegant method of conducting parallel reactions at a micro scale. The method includes the steps of providing an array of reaction vessels and providing a plurality of homogenous reaction mixtures within the reaction vessels. Each mixture comprises monomers at least partially embodied in a liquid and is provided in an amount sufficient to form a film having a thickness sufficient to allow the reaction rate of the polymerization reaction to be essentially independent of mass transport. Polymerization then takes place in the presence of a catalyst at reaction conditions effective in substantially maintaining the homogeneity of the reaction mixture. In this manner, polymerization can take place without stirring the reactants.
The method is particularly useful for reactions that produce polycarbonates, such as the reaction of diarylcarbonates and bisphenols to produce polycarbonates. Other polymer reactions amenable to utilization of the present method include ring-opening polymerizations and melt polymerizations to form polyesters, polyamides, polyimides, and mixed co-polymers. Generally, the method is useful for discovery of new catalysts, for optimization of reaction conditions, and for evaluation of new monomers to produce new polymers on a micro-scale in quantities sufficient for traditional characterization.
REFERENCES:
patent: 5472672 (1995-12-01), Brennan
patent: 5609826 (1997-03-01), Cargill et al.
patent: 5785927 (1998-07-01), Scott et al.
patent: 5792431 (1998-08-01), Moore et al.
patent: 5985356 (1999-11-01), Schultz et al.
patent: WO 93/09668 (1993-05-01), None
patent: WO 99/04247 (1999-01-01), None
Carnahan James Claude
Leib Terry Kay
Lemmon John Patrick
Potyrailo Radislav Alexandrovich
Warner Gregory Lee
Boykin Terressa M.
General Electric Company
Johnson Noreen C.
Stoner Douglas E.
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