500-05-0Relevant articles and documents
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Engel,C.R. et al.
, p. 3263 - 3271 (1973)
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Synthesis method of methyl coumalate
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Paragraph 0028-0029; 0031-0032; 0034-0035; 0037-0038; 0040, (2020/04/06)
The invention discloses a synthesis method of methyl coumalate. The synthesis method comprises the following steps: adding water-containing sulfuric acid into a kettle, stirring, heating to a temperature of less than 100 DEG C, and adding a pre-prepared saturated malic acid solution in a dropwise manner; carrying out a constant-temperature reaction after the adding, and monitoring the reaction process by using gas chromatography until the malic acid reaction is finished; stopping the stirring, layering, cooling to below 50 DEG C, and separating out a lower layer sulfuric acid aqueous solution;continuously stirring, heating to reflux, and adding a large amount of methanol in a dropwise manner; carrying out a reflux reaction for a certain time, and carrying out gas phase monitoring until coumalic acid disappears; evaporating out most of the solvent to form a slurry in the system, cooling to room temperature, and adding an aqueous solution of an alkaline compound in a dropwise manner toform a large amount of precipitates; and filtering, washing with water, and drying to obtain the methyl coumalate.
Four hydrogen pyrane two fluorine Asia armor propoxycyclohexyl linking group containing a liquid crystal compound, preparation method and application thereof
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Paragraph 0039; 0041-0044, (2017/03/08)
The invention discloses a liquid crystal compound containing a tetrahydropyrane difluoro methoxy-linking group and a preparation method and application thereof. The liquid crystal compound is represented by a formula I. In a molecular structure of the compound represented by the formula I, the liquid crystal compound containing the tetrahydropyrane difluoro methoxy-linking group (img file='DDA0000475765100000011. TIF' wi='384' he='112'/) has high dielectric anisotropy. What's more important is that the liquid crystal compound further has high response speed and clearing points and low rotational viscosity. Compared with blended liquid crystal compounds, the liquid crystal compound has very important significance. As the formula I, (img file='DDA0000475765100000012. TIF' wi='984' he='256'/).