JPS5826852A - Purifying method of crude phenylhydrazine - Google Patents

Abstract

PURPOSE:To purify crude phenylhydrazine into a purified, almost colorless and transparent substance having improved color tone in purifying the crude phenylhydrazine after distilling away an extracting agent by the rectification or simple distillation, by the presence of hydroxide of an alkali metal or alkaline earth metal. CONSTITUTION:A salt of phenylhydrazine obtained by the diazotation reduction and hydrolysis of aniline is neutralized with an alkali and extracted with an organic solvent. The extracting agent is then distilled away to give crude phenylhydrazine, which is then rectified or distilled simply in the presence of 0.06- 10wt% one or two or more hydroxides of an alkali metal or alkaline earth metal, e.g. sodium or lithium hydroxide, at an operating pressure of 200mm.Hg or less and purified to give a colorless transparent phenylhydrazine. This method reduces the volatility of volatile colored substances, and inhibits the formation of the volatile colored substances by the thermal decomposition of the phenylhydrazine itself.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention involves the diazotization, 7-element, and hydrolysis reaction of aniline. After neutralizing the resulting phenylhydrazine salt with an alkali and extracting it with an aqueous solvent, Distill C? The present invention relates to a method for obtaining almost polarized and transparent phenylhydrazine from phenylhydrazine of which %.

Phenylhydrazine is used as an important basic intermediate in various pharmaceuticals, chemicals, dyes, etc. Methods for producing phenylhydrazine, such as diazotization of aniline, diazotization, and hydrolysis reactions, include, for example, organic synthesis [
Organic 5 synthesis coll, vo
l, 1,442.1982, (j,) 1,0oler
Generally speaking, aniline hydrochloride is C-diazotized with sodium nitrite to form a diazonium salt, and this is treated with sodium sulfite to form phenylhydrazine disulfonic acid. After obtaining the sodium salt, a r tan water splitting reaction is performed using hydrochloric acid, and the resulting phenylhydrazine hydrochloride is neutralized with an alkaline solution to obtain phenylhydrazine. This phenylhydrazine can be mixed into benzene, toluene,
The target crude phenylhydrazine can be obtained by extraction using an organic solvent having high affinity for phenylhydrazine Iζ such as xylene (σ), and then distilling off the extractant. Normally, the crude phenylhydrazine obtained by straining is subjected to one column of distillation to obtain clear phenylhydrazine.

From the above, the phenylhydrazine produced by this method 1C/F4 is 1L1. In terms of quality, it is not necessarily something that can be improved, and there is a point that the special electric product is colored and there is a strong desire for improvement. Jrganic 8ynthe
sis Co11. vol, l, 443゜1932,
(j, H6Coleman) + ko, ko (7)
It has been reported that the phenylhydrazine obtained by the method is a yellow liquid, and the inventors of the present invention have thoroughly examined the testicles and found that this problem of coloration has not been solved. Flat that repeats the swamp of Fenylhydrazine
It became clear that Koyotsu C could not be resolved by simply improving the rectification conditions.

In addition, JP-A-54-149B2 @ Publication Telephone is almost colorless and transparent than crude phenylhydrazine and JIS-4879.
5 + 1 oz. of vinegar solution 1 oz. C Obtain a higher quality phenylene rehydran that is sufficiently transparent. A method has been described in which crude phenolic rehydrazine is treated with a mixture of alkali metal or alkaline earth metal hydroxides and then distilled in the presence of glycols. However, this method has drawbacks such as the inability to sufficiently suppress the thermal decomposition of phenylhydrazine itself in ζ during production, and the resulting formation of volatile colored substances.

Wood inventors and others are happy to improve these X points.

As a result of repeated studies, it was found that when obtaining crude phenylhydrazine after extraction, 1% or 2 or more rods selected from hydroxides of alkali metals or alkaline earth metals should be present. It was discovered that by doing so, it was possible to obtain phenylhydrazine which was substantially colorless and had a significantly improved color tone, thereby completing the present invention. Koto-1ko.

By the way, when alkali metals or alkaline earths are used, yellowish phenylhydrazine is obtained as a distillate. For example, when the operating pressure is 300 rnHf, the Gardner color number of the distillate (method according to JIS K54001) is about 4 to 5
It is.

The substance responsible for this coloring or staining is currently unknown, and the mechanism behind the formation of alkali metal or alkaline earth metal hydroxides is also unknown, but normal physical FIφ colorant binding with adsorption action
Activated carbon, alumina oxide, carbon dioxide, etc., which contain tc, do not provide any anti-coloration effect, and the method of the present invention is to use the hydroxide of an alkali metal or alkaline earth gold layer in the method of the present invention. Therefore, it is a luxury to be able to exert a specific and remarkable effect.

The hydroxides of alkali metals or alkaline earth metals used in the method of the present invention are commercially available such as sodium hydroxide, potassium hydroxide, lithium hydroxide, magnesium hydroxide, and hydroxide. Calcium etc. are preferably used - Koatto C can be used as an aqueous solution of these or remain as a solid. If it is necessary to separate water from this, it is preferable to use a solid alkali full thickness or alkaline earth metal hydroxide that does not contain water.

Although the method of adding an alkali metal or alkaline earth metal hydroxide to phenylhydrazine is not prohibited, it is possible to distill the desired phenylhydrazine.
When purifying the product and obtaining it from the top of the column, it is better to add 1 g of crude phenylhydrazine, which is the supply port to the distillation column, to distill out the desired product, phenylhydrazine. The same effect can be obtained by adding metal hydroxide to C. Alternatively, a method may be used in which crude phenylhydrazine is made into an alkali metal distillate in advance and subjected to C2, but after contact with the solid, the paddy phenylhydrazine contains alkali gold or alkaline earth with a certain degree of severity. In order to obtain phenylhydrazine in the presence of a metal hydroxide, one or more selected from the hydroxides of alkali metals or alkaline earth metals are used. It is necessary to carry out the process in the presence of crude phenylhydrazine containing carbon, which is a volatile compound of alkali gold or alkaline earth metal hydroxide used in the process of the present invention. Coexistence with phenylhydrazine plays a role, and 1% by weight of rO,06-10 is sufficient. Coexistence M′
If it is less than this lower limit, the resistance to discoloration may be slightly improved, but it is not fully satisfactory. As a side dish, crude feed and nylhydrazine V were obtained by a general method, and 0.05% by weight of phenylhydrazine with rlI2 to 3 was obtained. When added, the coloring prevention IE effect is sufficient, but the alkali metal viscosity becomes abnormally high.
It is difficult to remove the communication pump, etc., and it becomes stiff. For this reason, it is easy to remove high-boiling substances, which results in a large loss of phenylene, which is uneconomical.

Tokorochi, alkali metals or alkaline earths When obtaining transparent phenylhydrazine of any color, the operation can be carried out either continuously or batchwise, but the operating pressure is 200 f.
fH? It is necessary to perform the following. In other words, in the presence of alkali metal or alkaline earth metal hydroxides, volatile colored substances are produced from the thermal decomposition of phenylhydrazine, and from this, the product is When phenylhydrazine appears yellow, the addition of alkaline metal hydroxide or alkaline earth metal hydroxide becomes meaningless. Therefore, C1 should be operated as low as possible, the evaporation temperature of phenylhydrazine! It is necessary to keep the temperature low to suppress the heat content.

It is also well known that one must be careful about the oxidation of phenylhydrazine due to oxygen heat.
It is carried out under i and q.

Crude phenylhydrazine, which is the antidote to the method for purifying phenylhydrazine according to the method of the present invention, is obtained by diazotizing aniline,
Although it is synthesized through reduction and hydrolysis reactions, the method of the present invention is not limited to these diazotization reactions, reduction reactions, and hydrolysis reactions.

The method of the present invention will be described in more detail below as an actual example. However, the present invention is not limited to these embodiments.

Practical Example 1 A cylindrical separable flask of 200 mm, equipped with a stirrer, a dropping funnel, a rod-shaped cryostat, and a cooling device, was charged with 2 parts, 500 parts of a heavy % hydrochloric acid aqueous solution, and 100 parts of aniline, and the contents were cooled down. While cooling the mixture to 0° C., 215 parts of a 36% sodium nitrite aqueous solution was poured into the mixture through a dropping funnel to carry out a diazotization reaction, thereby obtaining 815 parts of a reaction solution. Next, prepare a separate aqueous solution of η base agent consisting of 205 parts of cauterized sodium chloride, 110 parts of sodium sulfite, and 700 parts of water, and add the diazotized parent reaction solution kept in OC. Injected in small quantities. After that, after holding at 45℃ for 30 minutes,
The temperature was raised to 90C+ and the reduction reaction was carried out while maintaining the temperature for 60 minutes. Next, 230 parts of an 85% hydrochloric acid aqueous solution was added dropwise little by little from the reducing reaction solution through the dropping funnel, and the mixture was kept at 90°C for 90 minutes to carry out a C hydrolysis reaction.

Next, this hydrolysis reaction solution was cooled to 40° C., and 400 parts of a 49% weighted sodium hydroxide aqueous solution was added from the dropping funnel to neutralize the solution, followed by dipping three times with 800 parts of toluene. Use all of the extracted toluene phase.
Toluene was distilled off under an OflMr. 110 parts of expanded phenylhydrazine was obtained from the flask.

2 parts of sodium hydroxide in the form of pellets of about 5 eggs in diameter were added to this phase phenylhydrazine, and the mixture was purified using a 300 CC round hole flask to obtain 100 parts of C phenylhydrazine.

This phenylhydrazine is transparent, almost daylight color, and its Gardner color number is below 1α.

Example 2 The same procedure as in Example 1 was carried out except that 2 parts of calcium hydroxide was used instead of 2 parts of sodium hydroxide used in Example 1, and 100 parts of phenylhydrazine was obtained. It was transparent and its Gardner color number was below IQ.

Practical example 8 Distilled phenylhydrazine was obtained when vaporization I was carried out in the same manner as in practical example 1, except that 2 parts of sodium hydroxide was replaced with 1 part and 4 parts, 6 parts, and 8 parts were used separately. In all cases, the colorimetry was almost transparent, and the Gardner color number was below RL.Example 4: In place of 2 parts of sodium hydroxide, potassium hydroxide, magnesium hydroxide, and lithium hydroxide were each added separately to 2 parts each. Phenylhydrazine was applied once in the same manner as in Practical Example 1, except that 4pt was used, but in each case, it was almost colorless and bright, and the Gardner color number was all below rlQ.

Practical example 5 A column filled with 100 parts of pelletized sodium hydroxide with a diameter of about 5M was sown with 110 parts of crude phenylhydrazine obtained in exactly the same manner as in Example 1, and then the number of theoretical plates was 5. This was charged into a distillation flask equipped with a packed column, and the gas was distilled from the capillary under the mechanical pressure of 5yHf under the conditions of a reflux ratio of 2 to obtain 95 parts of c1 phenylhydrazine as a fraction. However, this phenylhydrazine is pale yellow and transparent, and its Gardner color number is 1LJ, which is below.
Ta. In addition, hydroxide (sodium hydroxide in crude phenylhydrazine after passing through a lithium-packed tower is 0.15%)
Met.

Comparative Example 1 110 parts of crude phenylhydrazine obtained in exactly the same manner as in Example 1 was mixed with freshwater fish at 4,000 ml of 10 w H-y without adding sodium hydroxide and without introducing nitrogen gas. 7 to obtain 100 parts of C phenylhydrazine as a distillate, but a yellowish brown color was obtained.
The number of Gardner colors is approximately 5.

This was carried out in the same manner as in Comparative Example 2, and 100 parts of phenylhydrazine was obtained, but one part was colored yellowish brown, and the Gardner color number was 4, which was the same color.

Comparative Example 3 In place of 2 parts of sodium hydroxide used in Example 1, 1.05% sodium hydroxide was used except for Example I.
100 parts of phenylhydrazine was obtained using the same method as above, but the color was slightly l fh, and the Gardner color number was about 2.5.
Agent: Patent attorney Kimura Narumi.

Claims (1)

[Claims] l) Diazotization, 7-element, and hydrolysis reaction of aniline - Is the salt of 1 phenylhydrazine obtained with an alkali? After extrusion, the extractant is distilled off to obtain a transparent phenylhydrazine of an alkali metal or alkaline earth metal. Method for purifying hydrazine. 2) Claim 1, wherein one or more types of fleas selected from hydroxides of alkali metals or alkaline earth metals are present in an amount of 0.06 to 10% by weight based on the crude phenylhydrazine sapon. A method according to claim 1, which includes: