Method for synthesizing 5-amide-6-hydroxy-2-(4-carboxylphenyl)benzoxazole

A p-carboxyphenyl, synthesis method technology, applied in the field of synthesis of 5-amino-6-hydroxy-2-benzoxazole, can solve problems hindering the preparation, expansion and application of high-performance PBO materials, and achieve good industrialization Prospects and advantages, reduce production costs, and produce obvious advantages

Inactive Publication Date: 2008-07-02
YANCHENG DRAGON CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The current technical status of high-cost and difficult preparation of PBO has seriously hindered the preparation, expansion and application of high-performance PBO materials

Method used

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  • Method for synthesizing 5-amide-6-hydroxy-2-(4-carboxylphenyl)benzoxazole
  • Method for synthesizing 5-amide-6-hydroxy-2-(4-carboxylphenyl)benzoxazole
  • Method for synthesizing 5-amide-6-hydroxy-2-(4-carboxylphenyl)benzoxazole

Examples

Experimental program
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Embodiment 1

[0033] Embodiment 1: Preparation of 5-amino-6-hydroxyl-2-(p-carboxyphenyl) benzoxazole (ABA)

[0034] 4.0g K 2 CO 3 Dissolve in 150ml of water solvent, add 3.0g NHAB (purity 96.5%) into the dilute alkali solution, stir and heat up to 80°C, hydrolyze for 50min until the solution is clear, and slowly add 8.0 g Na 2 S 2 o 4 , control the reduction reaction at 0-5°C for 20 minutes, filter to obtain yellow crystals, wash with ice water, and vacuum-dry to obtain 2.12 g of light yellow crystalline products with a purity of 98.9%. After qualitative FT-IR, 13 C-NMR, 1 H-NMR attribute analysis and elemental analysis, determined to be a new monomer of acid type AB type PBO: 5-amino-6-hydroxyl-2-(p-carboxyphenyl)benzoxazole ABA monomer, yield 84.2% .

[0035] FT-IR (KBr, cm -1 ): 3333.4, 3269.7, 3151.1, 1676.8, 1617.0, 1579.4, 1466.6, 1409.7, 1380.8, 1294.0, 1177.3, 1129.1, 1053.9, 972.9, 879.4, 860.1, 784.9, 709.7. Elemental analysis values: C, 62.03; H, 3.75; N, 10.45. Calcula...

Embodiment 2～6

[0037] Adopt the same operation of embodiment 1, get different parameters (different temperature, raw material purity and Na 2 S 2 o 4 Consumption) reacts, and the results are shown in Table 1:

[0038] Table 1 Hydrolysis of Na by NHAB 2 S 2 o 4 Reduction "one-pot method" to prepare ABA monomer

[0039]

Embodiment 7

[0040] Embodiment 7: Alkaline hydrolysis, hydrogenation reduction in-situ synthesis method prepares ABA

[0041] 4.5g K 2 CO 3 Dissolve in 180ml of water solvent, add 3.00g of NHAB (purity 94.4%) into the dilute alkali solution, stir and heat up to 60°C, hydrolyze for 60min until the solution is clear, transfer the reaction solution to a high-pressure reactor, add 0.3g 5% Pd / C, stirred vigorously at 30°C and 0.3-0.4MPa hydrogen pressure for 3 hours, filtered to remove the catalyst, cooled the filtrate to room temperature and decolorized it with activated carbon, then used NaHSO 3 The saturated aqueous solution was adjusted to pH 6.5-7.0 to precipitate a precipitate, which was filtered and vacuum-dried to obtain 2.05 g of a khaki crystalline product with a purity of 98.2% and a yield of 82.6%. FT-IR, 13 C-NMR, 1 H-NMR attribute analysis is the same as that of Example 1 and is characterized as ABA monomer.

[0042] FT-IR (KBr, cm -1 ): 3334.3, 3269.7, 3146.3, 1675.8, 1617....

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Abstract

The invention relates to a synthesis method of 5-amido-6-oxhydryl-2-(4-carboxyl benzyl group) benzoxazole (ABA), which takes 5-nitryl-6-oxhydryl-2-(4-methoxycarbonyl phenyl) benzoxazole (NHAB) as raw material that is put into hydrosolvent for hydrolysis by alkaline substance at 60-100 DEG C and then one-spot method is directly used for preparing the ABA through in situ synthesis with the effect of reducer, wherein, the alkaline substance is carbonate of alkali metals. Mass ratio of feeding of the NHAB to the alkali substance is 1:0.8 to 2.25, and the reducer is sodium hydrosulfite (Na2S2O4) or hydrogen. When the Na2S2O4 is used as the reducer, the dosage is 2.0-3.0 time of the mass of the NHAB. The invention has concise technique, high yield and low requirement for equipment. The solvent used in the invention is water, which avoids induction of organ solvent, thereby reducing production cost without polluting the environment. The prepared ABA has high purity and better polycondensation effect, thereby showing good industrial prospect.

Description

(1) Technical field [0001] The invention relates to a synthesis method of 5-amino-6-hydroxyl-2-(p-carboxyphenyl)benzoxazole (ABA). (2) Background technology [0002] PBO is the abbreviation of cis-poly(p-phenylene-2,6-benzobisoxaole), which is cis-poly-p-phenylene benzobisoxazole, and it can be obtained by polymer liquid crystal spinning technology, which is the most organic and inorganic fiber. High Performance Fiber - Zylon. [0003] Research so far, Japanese Toyobo (Toyobo) company patent (patent open 2000-38371) is by (1) formula by 4,6-diaminoresorcinol hydrochloride (DAR 2HCl) and p- Phthalic acid (TPA) mixed polycondensation reaction to obtain PBO resin: [0004] [0005] Although the obtained Zylon-HM type PBO fiber has exhibited very excellent physical, chemical and mechanical properties, its production equipment requirements are very high, and the process condition control is extremely harsh, which is difficult to achieve and realize except for Toyobo in Japan...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D263/57
Inventor 金宁人郑志国曹义文金宁东王学杰
Owner YANCHENG DRAGON CHEM
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