JP3221993B2 - Preparation of monoallyl hydrazine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a mixture of hydrazine mono allylhydrazine _{(CH 2 = CHCH 2 NHNH 2} ), it relates to a method of separating a monoallyl hydrazine. Monoallyl hydrazine targeted by the present invention is a pesticide,
It is a compound useful as a raw material for pharmaceuticals and an intermediate for synthetic chemistry.

[0002]

2. Description of the Related Art As a method for producing monoallyl hydrazine, a method of reacting allyl chloride with hydrated hydrazine in ethanol and purifying it as a hydrochloride salt {Chem. B
er. 47 (1914) 3031} is known,
In this method, the yield of monoallyl hydrazine is low and the method is not practical. Further, a method of deriving a hydrazine hydrate to an alkylidene-acyl-hydrazine, followed by allylation and hydrolysis (Japanese Patent Application Laid-Open No. 2-67268) has also been disclosed, but the process is too complicated to produce an industrial process. Can not be.

The inventors have already proposed a process for producing monoallyl hydrazine comprising reacting allyl chloride in an excess of hydrated hydrazine (patent pending). This method has high selectivity to monoallyl hydrazine and is economical, but since the reaction product is obtained as a solution of monoallyl hydrazine dissolved in excess hydrated hydrazine, distillation and extraction with an aqueous alkali solution are performed. Monoallyl hydrazine is separated by combined use.

[0004]

However, the alkaline aqueous solution extraction method requires post-treatment of the extract, the number of steps is large, the treatment is complicated, and it is not necessarily an advantageous method. there were. The present invention efficiently separates a mixture of excess hydrazine hydrazine and monoallyl hydrazine, and obtains high-purity monoallyl hydrazine,
An object of the present invention is to provide a method for efficiently collecting and reusing unreacted hydrazine hydrate.

[0005]

According to the present invention, when a mixture of monoallyl hydrazine and hydrazine is separated, the mixture is distilled in the presence of water having a molar number larger than that of hydrazine to recover monoallyl hydrazine. A method for producing monoallyl hydrazine is provided.

According to the present invention, when separating a mixture of monoallyl hydrazine and hydrazine, (I) a mixture of monoallyl hydrazine, hydrazine and water having a mole number larger than hydrazine is distilled off as a feed solution, A first step of recovering a mixture of monoallyl hydrazine and water containing hydrazine as a top component, and recovering a mixture of hydrazine and water as a bottom component, and (II) supplying a top component of the first step to remove water. A second step of recovering monoallyl hydrazine and a small amount of water and hydrazine as a bottom component, and (III) supplying a bottom component of the second step as a column top component, and a small amount of monoallyl hydrazine, hydrazine And a third step of recovering water as a top component and the remaining monoallylhydrazine as a bottom component, and further adding water to the top component of the third step (III). And a method for producing monoallyl hydrazine, wherein the method is recycled to the feed solution of the first step (I).

[0007]

The boiling point of hydrazine is 114 ° C (760 mmH
g) but water and the highest boiling azeotrope {boiling point 120 ° C.
(760 mmHg) It is known that hydrazine: water = 58: 42 (molar ratio) is formed. According to the measurements by the inventors, the boiling point of high-purity monoallyl hydrazine is 127 ° C. (760 mmHg), and the monoallyl hydrazine, hydrazine and water are heated at 115 ° C. (760 mm Hg).
(mmHg) was found to form a ternary azeotrope {monoallyl hydrazine: hydrazine: water {32:36:32 (molar ratio)}.

[0008] From these facts, it is difficult to separate a mixture of monoallyl hydrazine and hydrazine into each component only by simple distillation, and particularly when excess hydrazine is present relative to monoallyl hydrazine, It is evident that the formation of a ternary azeotrope can be expected to prevent purification to a molar ratio of monoallylhydrazine: hydrazine ≒ 1: 1 or more.

The inventors of the present invention have made intensive studies, recognizing that separation of a mixture of hydrazine hydrate and monoallyl hydrazine is a key point in a method for producing monoallyl hydrazine. As a result, by distilling a mixture of monoallyl hydrazine and hydrazine in the presence of water equal to or more than the number of moles of hydrazine, high-purity monoallyl hydrazine can be obtained, and unreacted hydrazine hydrate can be recovered and reused. I found it.

That is, in the research process leading to the present invention, 1) monoallyl hydrazine and water do not form an azeotropic mixture,
2) The specific volatility of monoallyl hydrazine and hydrazine greatly changes due to the presence of water. In particular, 3) at a top temperature of 115 ° C. or lower during distillation, the lower the temperature, the higher , The ratio of monoallyl hydrazine to hydrazine increased, and 4) during distillation, the temperature at the top was found to decrease with the amount of water present,
The present invention has been completed based on these.

It is extremely unique that monoallylhydrazine having a higher boiling point than the azeotrope of hydrazine and water is concentrated in the overhead component due to the presence of water. Is the basis of

In a series of separation methods of the present invention, a mixture of excess hydrazine hydrate and monoallyl hydrazine is distilled in the presence of a specific range of water to remove most of the excess hydrazine hydrate to a concentration that can be reused. , And a distillate consisting of monoallylhydrazine, hydrazine and water is taken out from the top of the column. Next, hydrazine accompanying the monoallylhydrazine is separated from the top component to obtain high-purity monoallylhydrazine.

[0013]

The mixture of monoallyl hydrazine and hydrated hydrazine used in the present invention is not particularly limited, but a reaction mixture obtained by reacting allyl chloride in hydrated hydrazine is preferable. The resulting hydrogen chloride is neutralized, and this mixture can be used as a raw material in the method of the present invention. Usually, the hydrazine allylation reaction is carried out under the condition of hydrazine / allyl chloride> 4 (molar ratio), and a typical reaction mixture is monoallyl hydrazine: hydrazine: water ≒ 16: 47: 37 (weight ratio).
With the composition After the above reaction, the salts formed by neutralization are separated or used as a raw material without separation.
It should be understood that the presence of soluble salts in the reaction mixture does not interfere with the practice of the present invention.

In the present invention, in order to completely separate monoallylhydrazine and hydrazine by distillation, the amount of water present in the system is extremely important. The hydrazine hydrate used for the allylation is industrially 100% hydrazine hydrate (equimolar mixture of water and hydrazine). When the number of moles of monoallyl hydrazine, hydrazine, and water is A, B, and C, respectively, C / B ≧ 1 in the allylation reaction system.
The reaction proceeds under the following conditions.

In the practice of the present invention in which monoallyl hydrazine is distilled off as the overhead component, it is necessary to determine the water concentration of the feed to the first step (I) so as to satisfy the condition of C / B> 1. is there. Most preferably, the water concentration is (C-
B) When A> 4 is satisfied, monoallyl hydrazine, hydrazine and water are obtained as the top components, hydrazine and water are obtained as the bottom components, the recovery ratio of the monoallyl hydrazine at the top is 99% or more, and the hydrazine column is obtained. A bottom recovery of 96% or more is obtained.

When the water concentration satisfies (CB) / A> 4, the distillation yield of high-purity monoallylhydrazine is 75 even in the one-pass operation in which the top component is not recycled in the third step (III). % Or more. The higher the molar ratio (CB) / A, the lower the distillation temperature at the top of the column and at the same time the first step (I)
The selectivity of monoallyl hydrazine to hydrazine in the distillate of the above is improved. If the molar ratio (CB) / A is made very large by adding water to the feed, a mixture of monoallyl hydrazine and water substantially free of hydrazine is distilled off. This means that monoallyl hydrazine and water do not form an azeotropic mixture, and in view of the fact that monoallyl hydrazine has the highest boiling point in the mixture of the present invention,
This is a very unique phenomenon.

Table 1 below shows the relationship between the distillation temperature at the top, the distillate composition and others. As is clear from Table 1, monoallyl hydrazine /
The weight ratio of hydrazine changes variously depending on the value of (CB) / A, and what (CB) / A is selected is determined from the viewpoint of the economical efficiency of the apparatus and energy. .

[0018]

[Table 1]

An embodiment of the present invention will be described with reference to a flow sheet of FIG. From line 1, a mixture of monoallyl hydrazine, hydrazine and water is supplied to tower-I. The composition of the supply liquid satisfies the molar ratio C / B> 1. Tower-I
The required number of stages varies depending on the molar ratio (CB) / A and also varies depending on the operating reflux ratio, but is preferably 15 to 20 stages. The top composition of the tower-I is monoallylhydrazine and water having a composition determined by the water concentration of the feed liquid, that is, the molar ratio {(CB) / A}. The three components of the distillate are determined. In a preferred embodiment, monoallyl hydrazine / hydrazine>
10 (weight ratio), so that the distilling temperature is 110
Lower than ° C. The bottom component of tower-I is a mixture of hydrazine and water in a molar ratio of C / B ≦ 1. This can be recycled to the allylation reaction system.

The top component of the column I is supplied to the column
Supplied to II. The column II distills only the water in the feed solution, and the composition of the mixed solution is adjusted to C / B <1. For this purpose, the column-II must have a sufficient number of stages for separating water and monoallylhydrazine, and
5 or more actual stages are required. If the number of stages is lower than this, water is not sufficiently distilled off, which eventually leads to a decrease in the recovery of monoallylhydrazine. The top of column-II is water and the bottom is monoallyl hydrazine, hydrazine and water in the feed from line 2, and C / B <
There is a relationship of 1.

The bottom of the column II is supplied from the line 5 to the column III.
Supplied to In tower-III, under the condition of C / B <1, high-purity monoallyl hydrazine was recovered as the bottom, and monoallyl hydrazine, hydrazine and water in the feed liquid from line 5 were recovered as the top. , They result in a ternary azeotrope composition. The ternary azeotrope in line 6 can also be cycled to line 1.

The above embodiments of the present invention are not limited to the above description. For example, a batch distillation carried out while maintaining the limited conditions, or a method other than the distillation after the first step of the present invention is carried out. Continuing the separation at is also part of the present invention. Hereinafter, the embodiment will be described in detail.

[0023]

EXAMPLE As shown in FIG. 1, distillation was carried out using three distillation columns. Column-I is a column having about 20 actual plates and operated at a reflux ratio of 9. The temperatures at the top and bottom were 109 ° C and 121 ° C, respectively. Column-II is a column having about 15 actual plates and operated at a reflux ratio of 3. The temperatures at the top and bottom were 100 ° C and 122 ° C, respectively. Tower-
III is a column having about 20 actual plates, operated at a reflux ratio of 8. The temperatures at the top and bottom are 115 ° C. and 12
8 ° C. Table 2 shows the composition of each line and the relationship of kmol / hour. As a result of distillation, high-purity monoallyl hydrazine was obtained from line 7.

[0024]

[Table 2]

[0025]

According to the present invention, monoallyl hydrazine, which has heretofore been difficult to produce and purify to high purity,
It is easily obtained by the usual operation of distillation.

[Brief description of the drawings]

FIG. 1 is a process chart of an embodiment of the present invention.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C07C 243/16 C07C 241/02

Claims (3)

(57) [Claims] 1. A method for separating a mixture of monoallyl hydrazine and hydrazine, wherein the mixture is distilled in the presence of more water than the number of moles of hydrazine to recover the monoallyl hydrazine. Manufacturing method. 2. When the number of moles of monoallylhydrazine, hydrazine and water is A, B and C, respectively, the water concentration in the mixture is defined as a concentration satisfying (CB) / A> 4.
2. The process according to claim 1, wherein monoallylhydrazine is recovered as a top component and hydrazine is recovered as a bottom component. 3. A method for separating a mixture of monoallyl hydrazine and hydrazine, wherein (I) monoallyl hydrazine,
Distillation of a mixture of hydrazine and water more than the number of moles of hydrazine as a feed solution, recovering a mixture of monoallyl hydrazine and water containing a small amount of hydrazine as a top component and a mixture of hydrazine and water as a bottom component A second step of supplying the top component of the first step, recovering water as the top component, and collecting monoallylhydrazine and a small amount of water and hydrazine as the bottom component; and
(III) supplying a bottom component of the second step, a third step of recovering a small amount of monoallyl hydrazine, hydrazine and water as a top component, and recovering the remaining monoallyl hydrazine as a bottom component, A process for producing monoallyl hydrazine, characterized by adding water to the top component of the third step (III) and recycling it to the feed solution of the first step (I).