Synthesis method of indole

A synthesis method and technology of indole, applied in the direction of organic chemistry, etc., can solve the problems of three wastes, poor selectivity, long reaction time, etc.

Inactive Publication Date: 2007-02-14
TIANJIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

But this method has the following disadvantages: (1) its hydroxymethylation reaction uses organic quaternary ammonium base Triton B as a catalyst, which is expensive; (2) the given example of its hydrogenation step adopts the zinc powder reduction method, and the three wastes problem is serious
But its reaction time is longer, and the yield of indole is lower, selectivity is poorer

Method used

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  • Synthesis method of indole
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  • Synthesis method of indole

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Experimental program
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Embodiment 1

[0039] A kind of synthetic method of indole is made up of following steps:

[0040] (1) Put 137g o-nitrotoluene, 220g dimethyl sulfoxide, 15g paraformaldehyde, and 5g 20% ​​NaOH aqueous solution into a 1000ml three-necked flask successively. The solution is brownish black at this time. Under stirring, heat up to 50°C for reaction After 70 minutes, the heating was stopped, and concentrated hydrochloric acid was added to the reaction system to adjust the pH to 7. The resulting reaction solution was distilled under reduced pressure, and the previous water-containing fraction was discarded to obtain a mixed solution of DMSO and o-nitrotoluene. The brown-black liquid is the crude product of o-nitrophenylethanol, and the obtained crude product is decompressed and fractionated to remove the dimethylol compound of the by-product o-nitrotoluene to obtain 50 g of o-nitrophenylethanol pure product with a yield of 36.5%. The yield of nitrotoluene is 80%;

[0041] (2) Add 446g of o-nitrop...

Embodiment 2

[0046] Methylolation reaction: Mix potassium hydroxide: o-nitrotoluene: paraformaldehyde: N, N-dimethylformamide in a weight ratio of 1: 1000: 500: 100, stir at 100 ° C, and react After 10 minutes, adjust the pH to 7.5, and conduct fractional distillation under reduced pressure to obtain o-nitrophenylethanol.

Embodiment 3

[0048] Methylolation reaction: Sodium phenoxide in a weight ratio of 1:10:5:50: o-nitrotoluene: 37-41% by weight aqueous formaldehyde solution: Ethylene glycol monomethyl ether is mixed at 150°C Stir and react for 4 hours, adjust the pH to 7, and fractionate under reduced pressure to obtain o-nitrophenylethanol.

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Abstract

The indole synthesizing process includes the following steps: 1. the hydroxymethylation reaction of alkali catalyst, o-nitrotuluene, paraformaldehyde and polar solvent through stirring at 0-150 deg.c for 10 min to 5 hr, regulating pH and decompression fractionizing to obtain o-nitro phenethyl alcohol; 2. the catalytic hydrogenation reaction of o-nitro phenethyl alcohol with added skeletal nickel catalyst at 50-200 deg.c and 1-100 atm hydrogen pressure for 1-20 hr to obtain o-amino phenethyl alcohol; and 3. cyclization reaction of o-amino phenethyl alcohol with added metal modified skeletal catalyst at 110-300 deg.c for 1-10 hr to obtain indole. The present invention has facile cheap material, low cost of catalyst, short reaction time and simple indole synthesizing process, and the product indole has wide use and high economic value.

Description

technical field [0001] The present invention relates to a kind of synthetic method of indole. Background technique [0002] Indole is an important fine chemical raw material, which is widely used in medicine, pesticides, spices, food and feed additives, dyes and other fields. The research on its application has been persistent, and new application fields are still being developed. At present, the indole synthesis techniques that have been industrialized mainly include the aniline method, the o-aminoethylbenzene method and the o-chlorotoluene method. The aniline method requires the use of aniline with a higher price, and in the reaction process, the aniline must be in a large excess to ensure the necessary selectivity, and the single-pass conversion rate calculated with respect to aniline is low, which affects the economy of the method. The o-aminoethylbenzene method needs to be carried out at high temperature (generally about 600° C.), and an expensive platinum catalyst is ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D209/08
Inventor 郭翔海沈家祥
Owner TIANJIN UNIV
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