- Preparation method of nitrogen-containing aromatic dicarboxylic acid
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The invention discloses a preparation method of nitrogen-containing aromatic dicarboxylic acid. The method includes: taking quinoline, isoquinoline, benzimidazole or benzotriazole and a derivative thereof as the raw materials, adopting oxone as the oxidant, employing a metal salt as the catalyst and using inorganic acid as the medium, adding a phase transfer reagent, and carrying out reaction to obtain nitrogen-containing aromatic dicarboxylic acid. The reagents used by the method are high in stability, convenient for transportation and storage, the operation is simple, the conditions are easily controllable, and the price is low, at the same time, the catalytic effect is good, the yield is high, and waste liquid treatment is easy, therefore the method is convenient for industrial large-scale production.
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Paragraph 0085-0088
(2020/03/02)
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- Preparation method for imidazolinone compound
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The invention provides a preparation method for an imidazolinone compound, belongs to the technical field of organic synthesis, and can solve the problems that a large amount of wastewater is producedand the content of impurities in the product is high in the existing process for preparing the imidazolinone compound. According to the preparation method for the imidazolinone compound provided by the invention, a solution of 5-alkyl pyridine-2,3-phthalate is synthesized from ammonium carbonate; the steps of adding water, extracting, refining and the like are avoided in post-treatment; the obtained solution of the 5-alkyl pyridine-2,3-phthalate is used for subsequent reaction; and the wastewater is not produced. Then, a catalyst is added in the process of preparing 5-alkyl pyridine-2,3-dimethylbenzene anhydride, and the pH is controlled in the subsequent reaction process, so that the production of the impurities can be avoided, and the product purity is improved. The imidazolinone compound prepared by the method provided by the invention can be used as a high-efficiency herbicide.
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Paragraph 0042; 0044
(2019/03/29)
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- Recovery method and production method of substituted or unsubstituted 2,3-pyridine dicarboxylic acid
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The present invention relates to the field of pyridine dicarboxylic acids, and discloses a recovery method and a production method of substituted or unsubstituted 2,3-pyridine dicarboxylic acid. The recovery method comprises: (1) adding an extraction liquid to a solution containing substituted or unsubstituted 2,3-pyridine dicarboxylic acid represented by a formula (I) to obtain a raffinate phaseand an extraction phase; (2) adding an alkali solution to the extraction phase, adjusting the pH value to achieve an alkaline state, and carrying out oil-water separation to obtain an organic phase and an aqueous phase containing substituted or unsubstituted 2,3-pyridine dicarboxylic acid; and (3) adding an acid solution to the aqueous phase, adjusting the pH value to achieve an acidic state, carrying out standing layering, and filtering to obtain the substituted or unsubstituted 2,3-pyridine dicarboxylic acid represented by the formula (I), wherein in the formula (1), R1, R2 and R3 respectively and independently are H, C1-C4 alkyl, C1-C4 alkoxy, halogen, hydroxy, nitro or amino. According to the present invention, the recovery method can greatly improve the recovery rate, has good extraction effect, is simple and easy to perform, and is suitable for industrial production. The formula (1) is defined in the specification.
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Paragraph 0161-0163
(2019/03/15)
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- Photolysis pathway of imazapic in aqueous solution: Ultrahigh resolution mass spectrometry analysis of intermediates
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Direct degradation of imazapic, an herbicide of the imidazoline family, has been investigated in aqueous solution at different concentrations, pH values, and temperatures. The efficiency of the photodegradation process has been evaluated through degradation rate constants that could be fitted best with pseudo-first-order kinetics (Ct = C0 e-kt). Ultrahigh resolution mass spectrometry (FTICR/MS) was used in electrospray ionization mode as a tool to study the photolysis process on a molecular level, whereas UV-vis and high-performance liquid chromatography/mass spectrometry analysis were used to follow, by time, the evolution of the intermediates. Taking advantage of the high resolving power of FTICR/MS to perform precise formula assignments taking account of the natural abundance of isotopes, we herein propose and demonstrate an approach using 2D-derived van Krevelen visualization (O/C, H/C, m/z) to confirm the formation of imazapic intermediates. Such an approach allows a qualitative analysis of intermediates and elucidates the plausible reaction pathways of the photolysis process. More than eight photoproducts were separated and identified as a phototransformation of the imidazole ring. A mechanistical pathway was proposed.
- Harir,Gaspar,Frommberger,Lucio,El Azzouzi,Martens,Kettrup,Schmitt-Kopplin
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experimental part
p. 9936 - 9943
(2009/10/02)
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- Method for the preparation of 2,3-pyridine-dicarboxylic acids and derivatives thereof
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There is provided an improved process for the preparation of substituted and unsubstituted 2,3-pyridinedicarboxylic acids in significantly enhanced yield by the nitric acid oxidation of the appropriately substituted quinoline precursor in the presence of a catalytic amount of Manganese.
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- Method for the preparation of substituted and unsubstituted 2,3-pyridine and quinolinedicarboxylic acids
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There is provided a process for the preparation of a substituted or unsubstituted 2,3-pyridine or quinolinedicarboxylic acid by hydrolysis of a substituted or unsubstituted 2,3-pyridine or quinolinedicarboxylic acid diester with an acid having an ionization constant pKa of less than 3.0 followed by isolation of the product as the free acid or an acid salt.
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- Process for preparing pyridine-2,3-dicarboxylic acid compounds
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A process for preparing pyridine-2,3-dicarboxylic acid compounds of the following formula: STR1 wherein R1 and R3 are, identical or different, each a hydrogen atom or a lower alkyl group, R2 is a hydrogen atom, a lower alkyl group, or a phenyl-(lower)alkyl group which may have halogen atom or lower alkyl group on its phenyl ring, and R4 and R5 are, identical or different, each a lower alkoxy group. The compounds are useful as an intermediate for preparing agricultural chemicals and pharmaceuticals.
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- Ozonolysis of Quinolines: A Versatile Synthesis of Polyfunctional Pyridines
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A simple, safe and efficient procedure, easily adapted to a large scale, is described for the synthesis of substituted quinolines 2, which are readily oxidized by ozone in the presence of mineral acid, followed by an oxidative work up with hydrogen peroxide to afford substituted 2,3-pyridinedicarboxylic acids 3a-d,f and acyl pyridines 3e, g.
- O'Murchu, C.
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p. 880 - 882
(2007/10/02)
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- Method for the preparation of pyridine-2,3-dicarboxylic acids
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The present invention provides a novel method for the preparation of pyridine-2,3-dicarboxylic acids by the oxidation of 8-substituted quinolines.
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- A method for the sequential oxidation of substituted-8-hydroxy-quinolines to produce substituted-pyridine-2,3-dicarboxylic acids
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The present invention provides a novel process for the preparation of substituted pyridine--2,3-dicarboxylic acids by the sequential peroxide--hypochlorite oxidations of substituted-8-hydroxy-quinolines.
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