- Ab initio structure determination of monoclinic 2,2-dihydroxymethylbutanoic acid from synchrotron radiation powder diffraction data: Combined use of direct methods and the Monte Carlo method
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The crystal structure of 2,2-dihydroxymethylbutanoic acid (C6H12O4) in monoclinic form has been determined ab initio from synchrotron radiation powder diffraction data. Two O and five C atoms were first derived by direct methods. Two missing O atoms and one C atom were found by the Monte Carlo method without applying constraint to their relative positions. Positional and isotropic displacement parameters of these non-H atoms were refined by the Rietveld method. Molecules are linked by hydrogen bonds and they make sheet-like networks running parallel to the (010) plane. The Monte Carlo method is demonstrated to be a powerful tool for finding missing atoms in partially solved structure.
- Tanahashi, Yusaku,Nakamura, Hisayoshi,Yamazaki, Satoru,Kojima, Yuko,Saito, Hideshi,Ida, Takashi,Toraya, Hideo
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- METHOD FOR PRODUCING DIMETHYLOLALKANOIC ACID
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PROBLEM TO BE SOLVED: To simply produce a dimethylolalkanoic acid such as a dimethylolpropanoic acid and a dimethylolbutanoic acid that is useful as a raw material of a polyurethane resin in high yield at low cost, and to produce a urethane resin and/or its water dispersion, an adhesive/coating/coating material and/or a repair agent. SOLUTION: A dimethylolalkanoic acid is produced by a first step of adding cycloalkanone to trimethylolalkane and obtaining a dehydrated and protected compound. a second step of adding a nitroxy radical derivative compound to the compound, and obtaining an oxidized compound, and a third step of deprotecting the compound obtained in the second step, and obtaining a dimethylolalkanoic acid. Furthermore, a urethane resin and/or its water dispersion, an adhesive/coating/coating material and/or a repair agent is produced using the dimethylolalkanoic acid. SELECTED DRAWING: Figure 1 COPYRIGHT: (C)2021,JPOandINPIT
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Paragraph 0043; 0051-0055
(2021/05/05)
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- Preparation method of 2,2-dimethylolbutyric acid
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The invention discloses a preparation method of 2,2-dimethylolbutyric acid; beta, beta-dihydroxymethyl butyraldehyde is produced by reaction of butyraldehyde and polyformaldehyde as raw materials under the action of an organic base catalyst, the beta, beta-dihydroxymethyl butyraldehyde is oxidized under the action of hydrogen peroxide to obtain beta, beta-dihydroxymethyl butyric acid, the beta, beta-dihydroxymethyl butyric acid is neutralized by an inorganic base to obtain beta, beta-dihydroxymethyl butyrate, and the beta, beta-dihydroxymethyl butyrate is distilled and filtered to obtain highpurity beta, beta-dihydroxymethyl butyrate, and finally, the 2,2-dimethylolbutyric acid is obtained by acidification of the high purity beta, beta-dihydroxymethyl butyrate under the action of an acid.The preparation method is characterized in that the 2,2-dimethylolbutyric acid is prepared by a new synthesis method, a recrystallization step in the traditional process is omitted, the reaction efficiency is high, the product is easy to separate, the yield of the product can be greatly improved, the waste is less, and the design idea of green chemistry is met.
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Paragraph 0029-0041; 0043-0045
(2019/10/01)
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- Production of dimethylolcarboxylic acid
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In the method of the present invention, a dimethylolcarboxylic acid is produced by reacting a trimethylolalkane and formaldehyde to prepare a cyclic formal having a formal protecting group, followed by the oxidation of the cyclic formal by using nitric acid as an oxidizing agent to prepare a cyclic carboxylic acid which is then subjected to cleavage to remove the formal protecting group. The formal protecting group protects two of the methylol groups against the oxidation to enable the production of the dimethylolcarboxylic acid with a high selectivity.
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- Cosmetic or dermatological topical compositions comprising dendritic polyesters
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The present invention relates to cosmetic or dermatological compositions capable of being applied to the skin, the keratinous fibers, the nails, the semimucous membranes and/or the mucous membranes, and which includes a dendritic polyester polymer having terminal hydroxyl functional groups or the combination of such a polymer with a film-forming polymer. It also relates to methods of cosmetic or dermatological treatment using these compositions as well as the use of the compositions for the preparation of dermatological or cosmetic compositions.
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