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Preparation method of 2,3-naphthalic acid

A technology of naphthalene dicarboxylic acid and phthalaldehyde monoacetal, which is applied in the preparation of carboxylate/lactone, organic chemistry, etc. It can solve the problems of difficult industrial production, high environmental pollution, and poor product purity. It is not easy to achieve The effect of obtaining, good purity and low cost

Active Publication Date: 2017-05-31
河北凡克新材料有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] The method uses dimethylformamide as a solvent, and under the action of sodium iodide, reacts α, α, α', α'-tetrabromo-o-xylene with maleic anhydride to generate 2,3-naphthalene dicarboxylic acid. There are significant disadvantages, such as poor product purity and low yield, only 73%, and the cost of raw materials required for the reaction is extremely high, which is highly polluting to the environment and difficult to realize industrialized production

Method used

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  • Preparation method of 2,3-naphthalic acid
  • Preparation method of 2,3-naphthalic acid
  • Preparation method of 2,3-naphthalic acid

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preparation example Construction

[0043] A kind of preparation method of 2,3-naphthalene dicarboxylic acid of the present invention, concrete implementation steps are as follows:

[0044] (I) Acetalization reaction: Add the reactant o-phthalaldehyde and alcohols with 2 to 4 carbon atoms, acid catalyst I and cyclohexane into the reaction vessel, and o-phthalaldehyde and alcohols with 2 to 4 carbon atoms The molar ratio of alcohols is 1:1~1.5, the addition amount of acidic catalyst I is 5~8% of the total reactant mass fraction, the addition of cyclohexane is 2~4 times of the total reactant mass, and the reflux fraction Water for 3 to 8 hours to obtain o-phthalaldehyde monoacetal; wherein the alcohols with 2 to 4 carbon atoms are any one of ethylene glycol, propylene glycol, isopropanol, n-butanol or isobutanol; acidic Catalyst I is any one of phosphoric acid, p-toluenesulfonic acid, potassium bisulfate or cation exchange resin.

[0045] (II) Reduction reaction: Heat tetrahydrofuran and reducing agent sodium bor...

Embodiment 1

[0051] (I) Acetalization reaction: Add the reactants o-phthalaldehyde, ethylene glycol, phosphoric acid, and cyclohexane into the reaction vessel, the molar ratio of o-phthalaldehyde and cyclohexane is 1:1, and the acidic catalyst I The added amount is 5% of the mass fraction of the total reactants, the added amount of cyclohexane is 2-4 times of the total reactant mass, heating and reflux for water separation for 3-8 hours to obtain o-phthalaldehyde monoacetal.

[0052] (II) Reduction reaction: After heating tetrahydrofuran and sodium borohydride to reflux for 0.5 hours, slowly add o-phthalaldehyde monoacetal for reduction reaction, the molar ratio of phthalaldehyde monoacetal and tetrahydrofuran is 1:2, reducing agent and The molar ratio of o-phthalaldehyde monoacetal is 1:1, continue to reflux for 1.5 hours after adding, and then add water and hydrochloric acid solution with a concentration of 25% in the micro-reflux state to terminate the reaction, the volume ratio of hydro...

Embodiment 2～5

[0058] Embodiments 2-5 adopt the same method steps as the above-mentioned embodiment 1, and the difference is the process parameters. The reaction steps and process parameters of embodiments 2-5 are shown in Table 1. The meanings represented by the abbreviations that appear in the table are: "catalyst (m%)" refers to the mass fraction of acidic catalyst I accounting for the total reactants in step (I), and "cyclohexane: total (m)" refers to cyclohexane and total The mass ratio of reactant, " aldehyde: alkane (mol) " refers to the mol ratio of o-phthalaldehyde and hexanaphthene; " first reflux " refers to the time of tetrahydrofuran and reductant heating reflux in step (II), " secondary reflux "Refer to the time of reflux after the addition of phthalaldehyde monoacetal, "aldehyde: THF (mol)" refers to the molar ratio of phthalaldehyde monoacetal and tetrahydrofuran, "HCl:H 2 O (v) " refers to the volume ratio of hydrochloric acid solution and water " temperature A " refers to t...

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Abstract

The invention discloses a preparation method of 2,3-naphthalic acid, belonging to the technical field of preparation of organic compounds used as medical and liquid crystal intermediates. According to the preparation method, o-phthalaldehyde is used as a raw material, and through performing acetalation reaction, reducing reaction, hydrolysis reaction, cycloaddition reaction, dehydration reaction and hydrolysis reaction in sequence, finally the 2,3-naphthalic acid is prepared. The preparation method optimizes the reaction steps and conditions and has the advantages of reasonable synthetic route, high purity and yield of product, low production cost, low pollution, easy industrialization and the like.

Description

technical field [0001] The invention relates to a synthesis method of a compound, in particular to a synthesis method of 2,3-naphthalene dicarboxylic acid, belonging to the field of organic chemical synthesis. Background technique [0002] 2,3-Naphthalenedicarboxylic acid, English name 2,3-Naphthalenedicarboxylic acid, molecular formula is C 12 h 8 o 4 , molecular weight 216, density 1.454g / cm 3 , melting point 238-240°C, boiling point 407.5°C, flash point 214.4°C. 2,3-Naphthalene dicarboxylic acid is an important chemical intermediate and has important applications in the field of fine chemicals. It can be used as a raw material or intermediate for the synthesis of liquid crystal display materials, medicines, pesticides, spices, and inks. However, the current market price of 2,3-naphthalene dicarboxylic acid is relatively high, mainly due to the difficulty in its industrial production and preparation, high cost of raw materials, and low product yield. The existing meth...

Claims

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Application Information

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IPC IPC(8): C07C63/38C07C51/09
CPCC07C51/09C07D307/88C07D307/92C07D493/18C07C63/38
Inventor 周维江白世康段军王泽勇
Owner 河北凡克新材料有限公司
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