4 showed improved lipophilic ligand efficiency and demonstrated robust glucose lowering in diet-induced obese mice. Synthesis of 3,3-diarylpyrrolidines from diaryl ketones. A process for crosslinking a diaryl ketone containing polymer, comprising contacting a diaryl ketone containing polymer with an alcohol or alkoxide or a mixture of. Patent US5. 26. 04. Crosslinking of polymers containing diaryl ketones. This is a continuation of Ser. No.: 0. 7/5. 32,4. ![]() Jun. 4, 1. 99. 0, now abandoned. FIELD OF INVENTIONThis invention relates to a process for the crosslinking of polymers containing diaryl ketones by reacting the polymers with alcohols and/or alkoxides and to the products of such process. Such crosslinked polymers have improved properties, such as chemical resistance. BACKGROUND OF THE INVENTIONIt is known in the art that the crosslinking of polymers can improve certain physical properties, such as chemical and solvent resistance, and retention of shape at high temperatures. It is the object of this invention to provide a convenient method for crosslinking polymers containing diaryl ketones, so as to improve such physical properties. SUMMARY OF THE INVENTIONThis invention concerns a process for crosslinking ketone containing polymer, comprising,an optional first step of contacting a diaryl ketone containing polymer with an alcohol and/or alkoxide, at a first temperature of about 5. By diaryl ketone is meant a group that has a carbonyl group in which the carbon of the carbonyl group is bound directly to two carbon atoms that are part of aromatic rings. For example, the simplest (monomeric) diaryl ketone is benzophenone, diphenyl ketone. The ketone group may be part of the main chain of the polymer or may be a pendant group. Preferred polymers for this process are poly(etherketoneketone), hereinafter PEKK, and poly(etheretherketone), hereinafter PEEK. TETRAHEDRON LETTERS Pergamon Tetrahedron Letters 44 (2003) 6331–6333 Novel direct reduction of diaryl ketones to diarylmethanes using supercritical 2-propanol. Ketone Diet Food ListEfficient Synthesis of Diaryl Ketones by Nickel. Scholarly Search Engine Find information about academic papers by weblogr.com. The repeat units of these polymers are shown below. The polymers, whether substituted or not, must be substantially stable at the temperatures at which the process is run. Any primary or secondary alcohol or alkoxide may be used in the first and/or second steps of the process. The alcohol or alkoxide must be substantially stable at the temperature at which the process is run, although small amounts of dehydration are acceptable. Primary alcohols or alkoxides are preferred. A process for crosslinking a diaryl ketone containing polymer, comprising, &numsp &numsp &numsp an optional first step of contacting a diaryl ketone. Read "ChemInform Abstract: Unsymmetrical Diaryl Ketones from Arenes." on DeepDyve, the largest online rental service for scholarly research with thousands of academic. With N-hetereocyclic carbene and palladium catalysis, diaryl ketones with a variety of functional groups that span from electron withdrawing to electron donatin. Page 9 Synthesis of 3,3-diarylpyrrolidines from diaryl ketones Alan R. Diarylacrylate 2m derived from pyridyl phenyl ketone exists as a single isomer in CDCl3. It is preferred if the alcohol or alkoxide is polyfunctional, that is contains two or more hydroxyl groups. It is especially preferred if the alcohol is a glycol, that is contains two hydroxyl groups. If alkoxide is present, a combination of alkoxide and alcohol (alkoxide dissolved in alcohol) will usually be used, since many alkoxides are solids (see also swelling agents, infra). The alkoxide can be formed in situ, as by the reaction of an alkali metal hydroxide, hydride or amide with the alcohol. In preferred alkoxides, the cation is an alkali metal or aluminum. The ratio of alcohol (plus alkoxide, if present) to polymer in the first step is about 0. An equivalent of alcohol (or alkoxide) is the equivalents of hydroxyl groups, including alkoxide. In order to effect crosslinking, it is desirable to maintain the amount of alcohol or alkoxide in actual contact with the polymer to a minimum. The alcohol may be contacted with the polymer as a liquid or vapor. At higher temperatures lower boiling alcohols may be present as vapors, or a pressure vessel may be used to confine the vapor or keep them liquids. Alcohols (and their derived alkoxides) useful in the process include, but are not limited to, methanol, ethanol, n- propanol, i- propanol, n- butanol, 2- butanol, 2- methyl- 1- propanol, xylylene glycol (o- , m- and p- isomers), neopentyl alcohol, 1- heptanol, ethylene glycol, benzyl alcohol, 1,4- butanediol, propylene glycol, penterythritol, trimethylol propane, 1,3- propanediol, 1,5- pentanediol, 1,6- hexanediol, and cyclohexanedimethanol, and 2,2- dimethyl- 1,3- propanediol. The strong dehydrating acid is a concentrated acid that has a tendency to dehydrate organic compounds such as alcohols. Such acids are well known to those skilled in the art. Preferred strong dehydrating acids are sulfuric acid, phosphoric acid, polyphosphoric acid, p- toluenesulfonic acid, methanesulfonic acid, trifluoromethanesulfonic acid, and the like. Sulfuric acid is especially preferred. These acids are usually used from about ambient temperature to about 1. Ketone DietThe glass transition temperature of a polymer is a property well known to those skilled in the art, and the value for any particular polymer can be found in the literature or measured by well known techniques, such as differential scanning calorimetry. If the glass transition temperature of the polymer is above about 2. If there is no alkoxide present in the first step, higher temperatures, about 1. If no acid is present and the first step has not been carried out, then alcohol and/or alkoxide must contact the polymer in the second step. The alcohols and alkoxides discussed above are applicable. For the second step carried out in the absence of acid, it is preferred that the temperature is about 2. Typically the amount of time needed to carry out the second step in the absence of acid is inversely proportional to the temperature. Although it will vary somewhat depending on the process ingredients, typical times for the second step are 1 hr at 2. Thus alcohols that can swell the polymer will typically crosslink not only the surface of the polymer but somewhat below the surface, the exact amount of penetration below the surface being determined by the ability of the alcohol to swell the polymer. There will usually be a . Another determining factor as to whether some crosslinking will occur throughout the polymer is the thicknesses of the polymer pieces, thicker pieces being less likely to be crosslinked in the center of the piece. In order to assist in crosslinking the polymer below the surface, especially if the alcohol/alkoxide does not swell the polymer well, it is advantageous to add to the process (first and second steps) a swelling agent which swells the polymer. Such agents must of course be substantially stable at the temperature of the process and not react with any of the other ingredients. The use of a swelling agent will aid in the crosslinking of the polymer below the surface whenever acid, alkoxide or alcohol are present. Suitable agents are 1,2,4- trichlorobenzene, methylene chloride and chloroform. Process steps carried out much above ambient temperatures should be done in the absence of oxygen to avoid oxidation of the process ingredients. If alkoxides or concentrated dehydrating acids are employed large amounts of water should be avoided. It is therefore often convenient to carry out the process under an inert atmosphere, for example nitrogen or argon. If the process is carried out using the optional first step, the polymer so produced may be formed into parts before performing the second step. For example, for polymers that can be melt processed below about 2. For polymers that cannot be melt processed below about 2. After the second step of the process the polymer should be of the final part configuration, such as a molding, extrusion, composite part, fiber, film, etc. Thus parts of the desired final configuration need only be treated by the second step in the presence of alcohol and/or alkoxide to become crosslinked. Parts that had undergone the first step could be formed into their final shapes before treatment in the second step. Parts crosslinked by the instant process, such as moldings, fibers and films are especially useful in environments with harsh chemical exposure such as acids. Such uses include filter for furnaces burning high sulfur content coals, protective clothing and engineering parts. They are also particularly useful where shape retention at high temperatures is critical. In some of the following examples PEEK polymer, grade 3. ICI Americas, Wilmington, DE, is used. PEKK polymer was made according to the procedure of U. S. In the following examples, the polymers are tested for solubility in solvents which would normally dissolve them. If the polymer is insoluble, it is deemed crosslinked. EXAMPLE 1. PEKK polymer (0. The polymer softened slightly, but did not melt. It was insoluble in hexafluoroisopropyl alcohol at room temperature and sulfuric acid at 1. Untreated PEKK polymer was molten at 3. Polymers treated at 2. Polymer treated at 1. All three polymers were insoluble in sulfuric acid, both at room temperature and at 1. This result indicates that even at the lowest temperature used, which is near the PEKK Tg of . The polymer gelled, and did not melt. It was insoluble in a 5. Untreated PEEK polymer dissolved in this solvent. EXAMPLE 4. PEKK polymer (1. The resulting glassy solid was insoluble and swelled in hexafluoroisopropyl alcohol. EXAMPLE 5. PEKK film (0. The resulting opacified film was insoluble in sulfuric acid, hexafluoroisopropyl alcohol, and a 5. EXAMPLE 6. A small section of a PEKK tensile bar (0. The resulting tensile bar section was insoluble in 1. EXAMPLE 7. PEKK yarn drawn at 2. The resulting yarn was insoluble in 1. The boiling temperature is 1. The cooled suspension was filtered, and the solid polymer washed with 1- heptanol and then 2- propanol. It was soluble in hexafluoroisopropyl alcohol, indicating that it was not crosslinked. It was insoluble in sulfuric acid, indicating that it had become crosslinked by that solvent. The washed and air- dried polymer was heated in a nitrogen atmosphere at 3. The polymer melted and then solidified, indicating gelation. The resulting gelled polymer was insoluble in hexafluoroisopropyl alcohol at room temperature and in sulfuric acid at 1. The resulting colorless, creasable film was insoluble and swelled in hexafluoro- isopropyl alcohol. Film made the same way from untreated polymer dissolved in this solvent. The crosslinked film was heated in the film press for an additional period of time, and swelling ratios (qm) and elongation in a thermomechanical analyzer (TMA) were measured, with these results. The yarn was removed from the solution, washed with 1- heptanol, then 2- propanol, then water, then methanol, and let dry in the air. About one- third of the yarn was then immersed in sulfuric acid, whereupon it turned a very deep, almost black, red. This suspension was heated at 1. Progress in the Synthesis of Diaryl Ketones Catalyzed by Soild Acids. Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. Publisher conditions are provided by Ro. MEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable. This publication is from a journal that may support self archiving.
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