Method and device for preparing ethylphenylhydrazine hydrochloride by pipelines

A technology of o-ethylphenylhydrazine and ethylphenylhydrazine, which is applied in the field of compound preparation, can solve problems such as inability to quickly achieve uniform mixing at the molecular scale, increase side reactions, and instability of diazonium salts, so as to overcome local uneven concentration , reduced residence time, simple post-processing effect

Active Publication Date: 2015-07-01
ZHEJIANG UNIV OF TECH
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Problems solved by technology

The diazotization reaction is a batch-type operation mode, and there are many defects in this method: the diazonium salt is unstable and easy to decompose when heated, so the diazotization reaction must strictly control the reaction temperature (generally around 0°C); The chemical reaction is a strong exothermic reaction, and the dropping rate of sodium nitrite must be strictly controlled during the reaction process; the traditional diazotization is a batch production method, and the diazonium salt stays in the reactor for a long time, which increases the probability of side reactions such as coupling and decomposition The traditional diazotization is a low-temperature reaction, and the ammonium salt is mostly in the state of solid precipitation. At this time, it is a solid-liquid reaction system, and its mass transfer effect is poor. The sodium nitrite solution cannot be quickly mixed into the ammonium salt mixture to achieve uniform mixing at the molecular scale. , increase side reactions, and easily cause safety accidents
[0003] The methods for the preparation of o-ethylphenylhydrazine hydrochloride by reduction of diazonium salt reported at present are: (1) with SnCl 2 Hydrochloric acid solution is reducing agent to carry out reduction (US4585877), and this method reaction time is long, and cost is high; (2) take sodium sulfite as reducing agent, the low-temperature diazonium salt solution that will prefabricate is added in the sodium sulfite solution of 85~90 ℃ and carry out reduction ( Chinese Journal of Pharmaceutical Industry, 1998,29 (2): 89), this method yield is low; (3) with sodium sulfite as reducing agent, the prefabricated low-temperature diazonium salt solution is added in the sodium sulfite solution cooled to 0 ℃ in advance, Then gradually raise the temperature to react (Acta Chemical Industry, 2005, 56(8): 1536-1540), the yield of this method is higher, but there are many temperature-changing processes, and the operation is more cumbersome

Method used

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  • Method and device for preparing ethylphenylhydrazine hydrochloride by pipelines

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] The structure of the reaction device is as figure 1 , the first tubular reactor: a single tube with a length of 1 m and a diameter of 1 mm; the second tubular reactor: a single tube with a length of 30 m and a diameter of 1 mm.

[0025] The operation steps are as follows:

[0026] Prepare o-ethylaniline hydrochloric acid aqueous solution: o-ethylaniline (1212g, 10mol), 37wt% concentrated hydrochloric acid (2470g, containing HCl 25mol), water 1725g;

[0027] Prepare sodium nitrite aqueous solution: sodium nitrite (690g, 10mol), water 1380g;

[0028] Preparation of sodium sulfite aqueous solution: sodium sulfite (3150g, 25mol), water 12600g;

[0029] The first tubular reactor 9 is preheated and kept at 80° C. by jacket a11, and the o-ethylaniline hydrochloric acid aqueous solution and the sodium nitrite aqueous solution are respectively stored in the first storage container 1 and the second storage container 2, and Continuously input into the first mixer 7 through the ...

Embodiment 2

[0031] The structure of the reaction device is as figure 1 , The second tubular reactor: the length of the tube is 10 m, and the diameter of the tube is 4 mm.

[0032] 37wt% concentrated hydrochloric acid consumption is 3450g (wherein containing HCl 35mol) in o-ethylaniline hydrochloric acid aqueous solution; Sodium nitrite consumption is 794g (11.5mol) in sodium nitrite aqueous solution; The molar flow ratio of o-ethylaniline and sodium nitrite is 1: 1.15; the residence time in the first tubular reactor 9 is 1s; in the reactor 13, the reaction is kept at 70°C for 3 hours;

[0033]Other operations were the same as in Example 1, and 950 g of o-ethylphenylhydrazine hydrochloride was finally obtained with a yield of 55% and a melting point of 180.3-181.5°C.

Embodiment 3

[0035] The structure of the reaction device is as figure 1 , The second tubular reactor: the length of the tube is 1 m, and the diameter of the tube is 10 mm.

[0036] 37wt% concentrated hydrochloric acid consumption is 3450g (wherein containing HCl 35mol) in o-ethylaniline hydrochloric acid aqueous solution; Sodium nitrite consumption is 794g (11.5mol) in sodium nitrite aqueous solution; The molar flow ratio of o-ethylaniline and sodium nitrite is 1: 1.15; the residence time in the first tubular reactor 9 is 1s; the reaction is kept at 95°C for 1.5h in the reactor 13;

[0037] Other operations were the same as in Example 1, and 967 g of o-ethylphenylhydrazine hydrochloride was finally obtained, with a yield of 56% and a melting point of 179.8-181.5°C.

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Abstract

The invention provides a specific device for preparing ethylphenylhydrazine hydrochloride by pipelines. The device comprises two tubular reactors with jackets, two mixers, three containers, three metering pumps and a reaction kettle, wherein the first mixer, the first tubular reactor, the second mixer, the second tubular reactor and the reaction kettle are sequentially connected by virtue of conduits; the first metering pump and the second metering pump are respectively arranged on the first container and the second container by virtue of conduits which are provided with stop valves and are connected with the first mixer; the three metering pumps are arranged on the third container by virtue of a conduit which is provided with a stop valve and is connected with the second mixer; the inlet of the reaction kettle is communicated with the outlet of the second tubular reactor; a pipeline is arranged at the outlet of the reaction kettle, is communicated with a posttreatment system and is provided with a stop valve. The invention further provides a method for preparing ethylphenylhydrazine hydrochloride by using the device. The method is convenient to operate and simple in posttreatment, and the product has good yield and high purity and is suitable for industrilization.

Description

(1) Technical field [0001] The invention relates to a compound preparation method and a special device thereof, in particular to a method for preparing o-ethylphenylhydrazine hydrochloride by pipeline technology and a special device thereof. (2) Background technology [0002] O-ethylphenylhydrazine hydrochloride is an intermediate for the synthesis of non-steroidal anti-inflammatory drug etodolac. The synthesis method is usually to use o-ethylaniline as a starting material to generate diazonium salt through diazotization reaction, and then After the reducing agent is reduced, hydrochloric acid is added to obtain it. The diazotization reaction is a batch-type operation mode, and there are many defects in this method: the diazonium salt is unstable and easy to decompose when heated, so the diazotization reaction must strictly control the reaction temperature (generally around 0°C); The chemical reaction is a strong exothermic reaction, and the dropping rate of sodium nitrite ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C243/22C07C241/02
Inventor 余志群苏为科
Owner ZHEJIANG UNIV OF TECH
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