Process for producing 5-iodo-2-methylbenzoic acid

A technology of methylbenzoic acid and iodo, which is applied in the field of preparation of 5-iodo-2-methylbenzoic acid, can solve the selectivity of 5-iodo-2-methylbenzoic acid and reaction that has not been developed. Issues not always satisfactorily achieved, rarely reported

Inactive Publication Date: 2008-07-30
MITSUBISHI GAS CHEM CO INC
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  • Abstract
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  • Claims
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Problems solved by technology

However, in the application of all these methods, the selectivity of the reaction is not always satisfactorily achieved.
Furthermore, such reactions are rarely reported for compounds with multiple substituents and electron-withdrawing groups, such as 2-methylbenzoic acid
Therefore, according to conventional techniques, no effective method has been developed to produce 5-iodo-2-methylbenzoic acid with high selectivity and high yield (based on iodine)

Method used

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  • Process for producing 5-iodo-2-methylbenzoic acid
  • Process for producing 5-iodo-2-methylbenzoic acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0054] Add acetic acid (76.5 grams), acetic anhydride (23.5 grams), 2-methylbenzoic acid (20.0 grams), iodine (14.4 grams), 70% iodic acid aqueous solution in the 200 milliliters three-neck flasks that reflux condenser is housed (8.6 g) and H-beta-type zeolite (4.6 g). The resulting mixture was reacted at a reflux temperature of 122°C for 4 hours. After the reaction was completed, the H-β-type zeolite was removed from the reaction mixture by filtration, and the filtrate was cooled to room temperature. Precipitated crystals were collected by filtration, whereby 29.3 g (after drying) of the product were obtained. The collected crystals and mother liquor were analyzed by HPLC (High Performance Liquid Chromatography) to obtain the following reaction results:

[0055] 2-Methylbenzoic acid: 97.0% (conversion rate)

[0056] 5-iodo-2-methylbenzoic acid: 92.0% (yield)

[0057] 94.8% (selective)

[0058] 3-iodo-2-methylbenzoic acid: 0.7% (yield)

[0059] ...

Embodiment 2

[0064] The procedure in Example 1 was repeated except that acetic acid (96.0 g), acetic anhydride (9.2 g), iodine (15.6 g), and periodic acid (5.5 g) was used instead of iodic acid, whereby 28.5 g of product were obtained. The following reaction analysis results were obtained:

[0065] 2-Methylbenzoic acid: 93.0% (conversion rate)

[0066] 5-iodo-2-methylbenzoic acid: 89.3% (yield)

[0067] 96.0% (selective)

[0068] 3-iodo-2-methylbenzoic acid: 0.2% (yield)

[0069] 0.2% (optional)

[0070] 5-iodo-2-methylbenzoic acid crystals: 73.7% (yield)

[0071] 5-iodo-2-methylbenzoic acid: 99.5% (purity in crystal form)

[0072] By analyzing the crystals thus obtained, it was found that the free iodine content was 5 ppm, and Li, Na, K, Mg, Ca, Sr, Ba, Sc, Y, Ti, Zr, V, Nb, Cr, Mo, W, Mn were not detected , Fe, Ru, Co, Rh, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, In, Si, Sn, Pb, P, Sb or S. Both Group 1 and Group 2 element contents are 1 ppm or...

Embodiment 3

[0074] The reaction of Example 1 was repeated under the same conditions, and H-β-type zeolite was removed from the reaction mixture by filtration. Water (50.0 g) was added to the filtrate, followed by cooling to room temperature. Precipitated crystals were collected by filtration, whereby 33.0 g of a product were obtained. The following reaction analysis results were obtained:

[0075] 2-Methylbenzoic acid: 97.0% (conversion rate)

[0076] 5-iodo-2-methylbenzoic acid: 92.0% (yield)

[0077] 94.8% (selective)

[0078] 3-iodo-2-methylbenzoic acid: 0.7% (yield)

[0079] 0.7% (optional)

[0080] 5-iodo-2-methylbenzoic acid crystals: 85.6% (yield)

[0081] 5-iodo-2-methylbenzoic acid: 99.8% (purity in crystal form)

[0082] By analyzing the crystals thus obtained, it was found that the free iodine content was 5 ppm, and Li, Na, K, Mg, Ca, Sr, Ba, Sc, Y, Ti, Zr, V, Nb, Cr, Mo, W, Mn were not detected , Fe, Ru, Co, Rh, Ni, Pd, Pt, Cu,...

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Abstract

The present invention provides a process for producing 5-iodo-2-methylbenzoic acid by iodizing 2-methylbenzoic acid, which comprises, as essential steps, a reaction step in which 2-methylbenzoic acid is iodized in the presence of a microporous compound, iodine, an oxidizing agent, and acetic anhydride and a purification step in which sublimation, distillation, crystallization, or a combination of two or more of these is conducted. By the process, 5-iodo-2-methylbenzoic acid, which is useful in functional chemicals such as medicines, can be easily obtained as a high-purity compound in a high yield. The production steps comprising reaction and separation / purification are simple from the standpoint of process operation and the purification load is small. Furthermore, the microporous compound, e.g., a zeolite catalyst, separated and recovered from the liquid resulting from the reaction can be repeatedly used after a simple treatment. Consequently, the catalyst has a long life and the target compound can be produced by the efficient process.

Description

technical field [0001] The invention relates to a preparation method of 5-iodo-2-methylbenzoic acid, which is used as a useful raw material for medicines, pesticides and functional compounds, and also relates to high-purity 5-iodo-2-methylbenzoic acid. More specifically, the present invention relates to a process for the preparation of 5-iodo-2-methylbenzoic acid in high yield and high selectivity by iodination of 2-methylbenzoic acid, and also to high-purity 5-iodo-2-methylbenzoic acid. Background technique [0002] There are already methods for the synthesis of 5-iodo-2-methylbenzoic acid, such as the reaction of 2-methylbenzoic acid with iodine in the presence of sodium nitrite and oleum (Journal of the Indian Chemical Society (1930 ), pp. 503-504) and the method of reacting 2-methylbenzoic acid with potassium iodide in the presence of thallium (III) trifluoroacetate (Journal of the Chemical Society.Perkin Transactions I.(1974), No. 2405-2409 Page). The former method g...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C51/363C07C63/70C07C51/43C07B61/00
Inventor 吉村贵史日高敏雄佐藤良文伏见则夫山田和宽
Owner MITSUBISHI GAS CHEM CO INC
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