Abstract:
Bis(halophthalimides) are prepared in mixture in an organic liquid such as orthodichlorobenzene or anisole, by a reaction at a temperatire of at least 150°C between at least one diamine compound and at least one halophthalic anhydride in the presence of imidization catalyst. The reaction mixture is maintained at about 15% by weight solids content and rich in the halophthalic anhydride by constantly monitoring the reaction mixture using analytical methods such as high performance liquid chromatography. The product mixture may be directly employed in the direct preparation of polyetherimides, and similar slurries may be employed to prepare other polyether polymers.
Abstract:
A continuous process for the preparation of monofunctional aromatic haloformates (MAH) having structure (I) wherein n is an integer from 1 to 5, and R1 represents hydrogen, a branched or unbranched alkyl group having from 1-15 carbon atoms, an aryl group which may be substituted or unsubstituted, a cycloaliphatic group which may be substituted or unsubstituted, or an arylalkyl group which may be substituted or unsubstituted, and X is F, Cl, Br or I the method comprising the steps of (a) introducing (1) an aqueous caustic solution; 2) a carbonyl chloride; 3) at least one monofunctional hydroxyaromatic compound; and 4) at least one inert organic solvent into a continuous reaction system; and (b) effecting contact between 1), 2) 3) and 4) for a time and at conditions sufficient to produce MAH of structure (I).
Abstract:
A method for preparing an aliphatic chloroformate comprising, introducing a mixture of at least one aliphatic hydroxyl compound, phosgene, at least one solvent, and optionally at least one organic base into a flow reactor to obtain a unidirectional flowing reaction mixture. The unidirectional flowing reaction mixture is maintained at a temperature between about 0°C and about 60°C to produce a single product stream comprising an aliphatic chloroformate, useful in the preparation of polycarbonates and co-polycarbonates.
Abstract:
In a continuous flow reactor one or more bisphenols is converted by the action of phosgene and aqueous base into a mixture of mono- and bisphenol chloroformates which are then treated with a catalyst, additional aqueous caustic and a monophenol to afford endcapped polycarbonates. At relatively high levels of added monophenol endcapped polycarbonate oligomers are obtained. The method is especially suited for the continuous preparation of endcapped oligomers of tetrabromobisphenol A polycarbonate. The method is characterized by efficient use of phosgene, and conversion of chloroformate groups to carbonate linkages aided by trialkylamine catalysts bearing at least one methyl group on nitrogen, such as N, N-dimethylbutylamine (DMBA).
Abstract:
A heat recovery system is disclosed, and includes a thermally-stable, organic working fluid which is based on a mixture of thiophene or a derivative thereof, and at least one hydrocarbon having a boiling point in the range of about 25°C to about 125°C. A method for recovering waste-heat from a power plant is also described, and includes the step of directing the waste-heat to the heat-recovery system as described herein. A photometric sensor system for the detection of oxidative activity in an industrial process is disclosed, and includes the working fluid described above, and a detector for detecting a color change in the fluid, which signifies oxidative activity.
Abstract:
This invention relates to a method for removing impurities from a brine solution, the brine solution comprising a water soluble chelating agent, the method comprising the steps of: a) adjusting the pH of the brine solution to a pH of from about 2 to about 4; b) passing the brine solution through a first functionalized resin; the first functionalized resin having functional groups capable of removing multivalent metal cations from the brine solution; c) adjusting the pH of the brine solution to a pH of from about 9 to about 11.5; and d) passing the brine solution through a second functionalized resin; the second funtionalized resin having functional groups capable of removing alkaline earth metal cations from the brine solution.
Abstract:
Provided herein are copolymers and copolymer compositions that are both hydrophilic and oleophobic. The copolymers include structural units derived from a fluoroalkyl monomer and a zwitterionic monomer. It further relates to membranes formed by coating a porous substrate with ihe copoiymeric compositions. The copolymeric coating imparts hydrophilicity and oleophobicity/oil-tolerance to the membranes. The uses of such membranes as microiiltration membrane or ultrafiltration membrane are also provided.
Abstract:
A method for removing ionic species from a desalination unit, comprises: (a) circulating a wash stream in a closed loop comprising a desalination unit and a precipitation unit, the wash stream flowing at a linear velocity of at least 5 cm/second through the desalination unit, the wash stream becoming more saline after passage through the desalination unit; and (b) removing a portion of calcium sulfate from the wash stream by precipitation in the precipitation unit to obtain a supersaturation degree of calcium sulfate in the wash stream entering the desalination unit in a range of from about 1.0 to about 3.0.
Abstract:
The specification describes a continuous process for the preparation of monofunctional aromatic chloroformates (MAC) having the structure (I) wherein n is an integer from 1 to 5, and R 1 represents hydrogen, a branched or unbranched alkyl group having from 1-15 carbon atoms, an aryl group which may be substituted or unsubstituted, a cycloaliphatic group which may be substituted or unsubstituted, or an arylalkyl group which may be substituted or unsubstituted.