摘要:
In an exemplary embodiment, 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 quickly and efficiently without stirring the reactants. The method is highly useful for testing reactants, catalysts, and associated reaction parameters.
摘要:
In a rapid and non-invasive method for characterizing aromatic polycarbonates, fluorescence intensities are determined at least two wavelength ranges and used to calculate a compositional or physical property of the sample. The method is suitable for determining the relative amounts of linear and branched polycarbonates, and it is fast enough to monitor the progress of polymerization reactions.
摘要:
This invention provides a method for preparing polycarbonates, which utilizes polycondensation catalysts which are compounds or complexes of Ruthenium (II) and (III). Preferred catalysts are compounds of the formula [Ru(aryl)3]2+2X−, where X is a counterion. We have found that this new class of catalysts provides excellent polymerization rates for the preparation of Bisphenol A polycarbonate from the melt polymerization of diphenyl carbonate and Bisphenol A.
摘要:
In one embodiment, the present method includes the steps of introducing a volume of a sample into a vapor delivery line and volatilizing at least a portion of the volume as it is carried through the vapor delivery line. At least a portion of the volatilized volume contacts a sensor element, which produces a signal that is monitored to reveal information about the sample. All components upstream of the sensor element are substantially free of sorbent materials so that the sample volume does not contact a substantially sorbent material before contacting the sensor element.
摘要:
Rapid, sensitive detection of analytes in small-scale samples is achieved with an analytical method in which samples are adsorbed on a sorbent material and probed spectroscopically. The method is suitable for monitoring the progress of reactions in combinatorial screening experiments.
摘要:
A sensor system for measuring a plurality of chemical species is disclosed. The sensor system includes a plurality of semiconductor device sensor elements, wherein each sensor element includes at least one wide band gap semiconductor layer and at least one catalytic layer configured to have an electrical property modifiable on exposure to an analyte including one or more chemical species; and an acquisition and analysis system configured to receive sensor signals from the plurality of sensor elements and to use multivariate analysis techniques to analyze the sensor signals to provide multivariate analyte measurement data.
摘要:
The present invention is directed to a method for the rapid screening of potential reactants, catalysts, and associated process conditions. In an embodiment, the invention comprises a method for evaluating catalyst efficacy in polymerization reactions by the determination of product molecular weight and Fries products.
摘要:
The present invention provides a method for directly determining the concentration of a target species, such as Fries product, in a composition comprising aromatic carbonate chain units. In an exemplary embodiment, the method includes the steps of irradiating a portion of the composition with electromagnetic radiation at an excitation wavelength sufficient to cause the target species to emit a fluorescence spectrum; detecting at least a portion of the fluorescence spectrum; and determining the concentration of the target species from the fluorescence spectrum. In addition to detecting Fries product in formed polycarbonate materials, the method can also be utilized to directly determine the concentration of a target species in parallel polycarbonate reactor systems.
摘要:
In an exemplary embodiment, the apparatus includes an electromagnetic radiation source, an optical analyzer, and a fiber optic bundle. The fiber optic bundle has an excitation fiber in optical communication with the electromagnetic radiation source and a plurality of emission fibers in optical communication with the optical analyzer. The optical analyzer can have multiple channels, including a fluorescence-emission channel in optical communication with the emission fibers. Optionally, the fiber optic bundle can further contain at least one reflection fiber in optical communication with an absorbance/reflectance channel. In addition to detecting Fries product in formed polycarbonate materials, the method and apparatus can also be utilized to directly determine the concentration of a target species in parallel polycarbonate reactor systems.
摘要:
The present invention is directed to a method and apparatus for rapid screening of potential reactants, catalysts, or associated process conditions. In one embodiment, the method includes the steps of providing a reaction substrate having at least one substrate reservoir and introducing a reactant system at least partially embodied in a liquid into the substrate reservoirs. The reactant system is heated to at least one predetermined temperature. A flow of inert gas is provided through a manifold above the substrate reservoir. The reaction in the substrate reservoir can be monitored, e.g., visually or spectrophotometrically during the course of the reaction, or the reaction substrate block can be rapidly cooled to stop the reaction in the substrate reservoir prior to analysis.