TW201350463A - A process for purifying organic product solution obtained from oxime synthesis section - Google Patents

Abstract

A continuous process for purifying organic product solution comprising oxime dissolved in an organic medium comprising: (1) discharging the organic product solution from a oxime synthesis section [I] to a liquid-liquid mixing section [III]; (2) mixing the organic product solution with a water and/ or an aqueous solution and discharging the resulting mixture to liquid-liquid separator [IV]; (3) separating organic top layer from aqueous bottom layer in liquid-liquid separator [IV] and recovering oxime from the organic top layer in an oxime recovery section; (4) feeding the aqueous bottom layer of liquid-liquid separator [IV] to the oxime synthesis section [I], optionally a fraction of which being fed back into the liquid-liquid mixing section [III].

Description

Method for purifying an organic product solution obtained from a synthetic portion of hydrazine

The present invention relates to a process for purifying cyclohexanone oxime dissolved in an organic medium.

Helium, especially cyclohexanone oxime, may be in a buffered aqueous reaction medium containing a buffer acid or an acid salt (for example, a phosphate buffer, and a buffer salt derived from such an acid) continuously in the hydroxylammonium The synthesis zone and the cyclohexanone oxime synthesis zone are recycled between the methods. In the hydroxylammonium synthesis zone, hydroxylammonium can be formed by catalytic reduction of nitrate ions or nitrogen monoxide by hydrogen. In the cyclohexanone oxime synthesis zone, the hydroxylammonium formed in the hydroxylammonium synthesis zone can react with cyclohexanone to form cyclohexanone oxime. The cyclohexanone oxime can then be separated from the aqueous reaction medium, which is recycled to the hydroxylammonium zone.

In the case where the synthesis of the hydroxylammonium salt starts from a solution of phosphoric acid and a nitrate, the chemical reaction described above is expressed as follows:

Reaction 1) Preparation of hydroxylammonium in the hydroxylammonium salt synthesis zone: 2H ₃ PO ₄ +NO ₃ ^- +3H ₂ →NH ₃ OH+2H ₂ PO ₄ ^- +2H ₂ O

Reaction 2) Preparation of hydrazine in the hydrazine synthesis zone:

Reaction 3) After removing the hydrazine formed in reaction 2), supplement HNO ₃ to make up the consumption of nitrate ion source: H ₃ PO ₄ + H ₂ PO ₄ ^- + HNO ₃ + 3H ₂ O → 2H ₃ PO ₄ + NO ₃ ^- +3H ₂ O

This first reaction is heterogeneously catalyzed. Preferably, the catalyst is dispersed as a ground solid in a liquid reaction mixture.

In the cyclohexanone oxime synthesis zone, cyclohexanone oxime can be countercurrently flowed through an aqueous medium comprising hydroxylammonium formulated in water with an organic medium comprising cyclohexanone dissolved in an organic solvent such as toluene or benzene. Made by contact. An organic solution containing the formed cyclohexanone oxime dissolved in an organic solvent is proposed from the reaction zone, and then distilled to recover cyclohexanone oxime.

From the course of the reaction, it is clear that the inorganic processing liquid may contain a neutral substance such as hydroxylamine or ammonia, which may also be protonated, such as hydroxylammonium or ammonium ions. This means that in the present invention, both hydroxylamine and hydroxylammonium can be regarded as hydroxylamine and/or hydroxylammonium, and ammonia and ammonium ions can be regarded as ammonia and/or ammonium ions.

The inorganic liquid leaving the deuteration synthesis zone must be completely purified to protect the catalyst in the hydroxylammonium synthesis zone. This is carried out in an inorganic liquid extraction section with a solvent such as toluene. Preferably, the inorganic liquid leaving the extraction section is fed into the washing section and the carbon adsorption section for further purification.

WO 2004/067497 relates to a process for the treatment of organic solutions comprising cyclohexanone oxime, cyclohexanone and organic solvents. In an example of this application, an organic product solution containing cyclohexanone oxime and cyclohexanone dissolved in an organic solvent [toluene] is discharged from the cyclohexanone oxime synthesis zone. Preferably, after washing with water or an aqueous solution, the organic product solution is fed into a distillation column. However, no specific cleaning method has been disclosed in this application.

The present invention provides a method for continuously purifying an organic product solution by washing.

The purpose of cleaning the organic product solution is to recover almost all of the inorganic processing liquid (IPL) salts from the organic product solution. This cleaning is based on the better physical properties of the IPL salt in water than in the organic product solution.

Thus, according to the present invention, there is provided a continuous process for purifying a solution comprising an organic product dissolved in an organic medium, comprising: (1) discharging the organic product solution from the synthesis section [I] of the hydrazine to the liquid - a liquid mixing section [III]; (2) mixing the organic product solution with water and/or an aqueous solution, and then discharging the resulting mixture to a liquid-liquid separator [IV]; (3) to a liquid-liquid separator [IV] separating the organic top layer and the aqueous bottom layer, and introducing the organic top layer into the ruthenium recovery portion; (4) feeding the aqueous bottom layer of the liquid-liquid separator [IV] into the synthesis portion [I] of the ruthenium, Optionally, one of the portions is fed back to the liquid-liquid mixing section [III].

Reference examples are set forth in the following figures.

Preferably, the aqueous medium containing a part of the organic product solution from the synthetic portion [I] of the crucible is before the liquid-liquid mixing portion [III], before the liquid-liquid The separator [II] was separated, and then the aqueous underlayer of the liquid-liquid separator [II] was introduced into the synthesis section [I] of the crucible.

Preferably, the organic top layer obtained in the liquid-liquid separator [IV] is sent to the liquid-liquid separator [V] before being recovered from the helium recovery portion, and the liquid-liquid The separator [V] can be a coalescer.

Preferably, the organic top layer obtained from the liquid-liquid separator [IV] is subjected to at least one re-cleaning portion before being introduced into the helium recovery portion. Preferably, the organic top layer obtained from the liquid-liquid separator [IV] is subjected to treatment of two kinds of re-cleaning portions before being introduced into the crucible recovery unit.

Preferably, the organic top layer of the liquid-liquid separator [IV] is introduced into the liquid-liquid separator [V] before being introduced into the re-cleaning section.

The re-cleaning zone comprises: (i) introducing an organic top layer of the liquid-liquid separator [IV] into the liquid-liquid mixing section [III ^a ], and mixing the organic top layer and the water and/or aqueous solution; (ii) Discharging the resulting mixture from the liquid-liquid mixing section [III ^a ] to the liquid-liquid separator [IV ^a ], and separating the organic top layer produced and the resulting aqueous bottom layer; (iii) separating the liquid-liquid Part or all of the aqueous bottom layer of [IV ^a ], introduced into the synthesis section [I] of the crucible, and/or introduced into the liquid-liquid mixing section [III], and/or introduced into the liquid-liquid mixing section [III ^a ] And/or disposed of; (iv) introducing the organic top layer of the liquid-liquid separator [IV ^a ] into the helium recovery section.

Preferably, the organic top layer obtained in the liquid-liquid separator [IV ^a ] is sent to the liquid-liquid separator [V ^a ] and the liquid-liquid separator before the helium recovery in the helium recovery section. [V ^a ] can be a coalescer.

An apparatus for purifying a crucible comprising at least one liquid-liquid mixer and at least one liquid-liquid separator. Preferably, the liquid-liquid separator [IV] or the liquid-liquid separator [IV ^a ] is a gravity liquid-liquid settling tank. The liquid-liquid mixing section [III] or the liquid-liquid mixing section [III ^a ] preferably contains a stirrer and/or a static mixer, preferably a stirrer.

Preferably, the aqueous solution in line [7] comprises demineralized water and/or vapor condensed water. The aqueous solution may also contain a small amount of ammonia. The amount of ammonia is preferably less than 30% by weight, more preferably less than 5% by weight and most preferably less than 1% by weight.

Preferably, the aqueous solution in line [14] comprises demineralized water and/or vapor condensed water. The aqueous solution in line [14] may also contain a small amount of ammonia. The amount of ammonia is preferably less than 30% by weight, more preferably less than 5% by weight and most preferably less than 1% by weight.

Preferably, the aqueous solution in line [19] comprises demineralized water and/or vapor condensed water. The aqueous solution in line [19] may also contain a small amount of ammonia. The amount of ammonia is preferably less than 30% by weight, more preferably less than 5% by weight and most preferably less than 1% by weight.

Preferably, the aqueous bottom layer in the liquid-liquid separator [IV] is fed into the synthesis section [I] of the crucible; optionally, a part thereof is fed back into the liquid-liquid mixing section [III].

More preferably, the water-based bottom of one of the liquid-liquid separators [IV] The layer is introduced into the liquid-liquid mixing section [III], and the remaining portion is sent to the synthesis section [I] of the crucible. Preferably, the amount of the aqueous underlayer to be introduced into the liquid-liquid mixing portion [III] exceeds 80% by weight, more preferably exceeds 90% by weight, and most preferably exceeds 95% by weight.

Preferably, ^a part or all of the aqueous bottom layer of the liquid-liquid separator [IV ^a ] is fed into the synthesis section [I] of the crucible, and/or fed into the liquid-liquid mixing section [III], and / Or feed into the liquid-liquid mixing section [III ^a ].

More preferably, the aqueous bottom layer of a portion of the liquid-liquid separator [IV ^a ] is introduced into the liquid-liquid mixing portion [III ^a ], and the remaining portion is sent to the liquid-liquid mixing portion [III], and / Or dispose of it. Preferably, the amount of the aqueous underlayer introduced into the liquid-liquid mixing portion [III ^a ] exceeds 80% by weight, more preferably exceeds 90% by weight, and most preferably exceeds 95% by weight.

Preferably, the organic top layer obtained from the liquid-liquid separator [IV] is subjected to treatment with two or more re-cleaning portions before being introduced into the helium recovery portion. Preferably, some or all of the aqueous bottom layer of the liquid-liquid separator of each re-cleaning process may be introduced into the synthesis section [I] of the crucible, and/or any one or more of the previous liquid-liquid mixing sections. Medium, and / or disposed of.

Preferably, the organic top layer obtained by each re-cleaning process can be introduced into the liquid-liquid separator before being introduced into the next re-cleaning process. Preferably, the liquid-liquid separator is a coalescer. Preferably, a part or all of the aqueous underlayer obtained in the liquid-liquid separator is introduced into the synthesis section [I] of the crucible, and/or any one or more of the previous liquid-liquid mixing sections, and The rest is disposed of.

Preferably, the hydrazine is cyclohexanone oxime.

Preferably, the organic solution is toluene.

Preferably, the temperature in the liquid-liquid mixing portion [III] is in the range of 30 ° C to 90 ° C, more preferably in the range of 40 ° C to 80 ° C, and most preferably in the range of 50 ° C to 70 ° C. .

Preferably, the temperature in the liquid-liquid mixing portion [IIIa] is in the range of 30 ° C to 90 ° C, more preferably in the range of 40 ° C to 80 ° C, and most preferably in the range of 50 ° C to 70 ° C. .

The organic product solution is subjected to a cleaning treatment to recover more IPL (inorganic processing liquid) salts, thereby reducing the loss of IPL salts. Another advantage is that no contamination occurs in the helium recovery section. In addition, it was found that relatively pure caprolactam was produced.

1, 2, 3, 4, 4A, 4B, 5, 6, 7, 8, 9, 9A, 9B, 10, 10A, 10B, 11, 12, 13, 13A, 13B, 13C, 13D, 14, 15, 16, 16A, 16B, 17, 17A, 17B, 17C, 17D, 18, 19, 20, 21, 21A, 21B, 22, 23, 24‧‧‧ pipeline

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III, III ^a , III ^b ‧‧‧ liquid-liquid mixing

IV, II, V, IV ^a , V ^a , IV ^b ‧‧‧ liquid-liquid separator

V, V ^b ‧‧‧ coalescer, liquid-liquid coalescer

Figures 1-4 show an overview of a method for purifying cyclohexanone oxime dissolved in an organic medium.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic illustration of a preferred embodiment of the method of the present invention.

Figure 2 is a schematic illustration of a preferred embodiment of the method of the present invention.

Figure 3 is a re-cleaning process.

Figure 4 is a schematic diagram showing the purification of cyclohexanone oxime dissolved in an organic medium comprising two re-cleaning steps.

figure 1:

A preferred embodiment of the method of the present invention is generally illustrated in FIG. In this specific example, cyclohexanone oxime is produced in the synthesis section [I] of cyclohexanone oxime. In the synthesis section [I] of cyclohexanone oxime, containing hydroxylammonium formulated in water and The aqueous medium of the organic ion is contacted with an organic medium comprising cyclohexanone and an organic solvent, preferably toluene. In the synthesis section [I] of cyclohexanone oxime, hydroxylammonium reacts with cyclohexanone to form cyclohexanone oxime. The aqueous medium and the organic medium are supplied to the synthesis unit [I] of cyclohexanone oxime via lines [1] and [2], respectively. The resulting aqueous layer was discharged from the synthesis portion [I] of cyclohexanone oxime via line [3].

The organic product solution containing cyclohexanone oxime and cyclohexanone dissolved in an organic solution (toluene) is discharged from the cyclohexanone oxime [I] at the discharge level of the organic product solution via line [4]. This organic product solution, which contains some water, hydroxylammonium, and inorganic ions, is supplied to the liquid-liquid mixing section [III] via line [4]. The liquid-liquid mixing section [III] may contain a stirrer and/or a static mixer, preferably a stirrer. Water or an aqueous solution is supplied to the liquid-liquid mixing section [III] via line [7]. The mixture of the aqueous medium and the organic medium discharged from the liquid-liquid mixing portion [III] is supplied to the liquid-liquid separator [IV] via the line [8]. In the liquid-liquid separator [IV], an organic top layer and an aqueous underlayer are formed. The aqueous bottom layer is discharged from the liquid-liquid separator [IV] via line [9]. Optionally, a portion of the aqueous bottom layer discharged from the liquid-liquid separator [IV] is supplied to the liquid-liquid mixing portion [III] via the line [9A] while the remaining portion is discharged via the line [9B]. To the synthesis of cyclohexanone oxime [I]. The organic top layer is discharged via line [10]. This organic top layer, which contains some of the remaining water, hydroxylammonium, and inorganic ions, can be directly discharged to the cyclohexanone oxime recovery section, in which a product mainly comprising cyclohexanone oxime can be obtained.

figure 2

A preferred embodiment of the method of the present invention is generally illustrated in FIG. In this specific example, cyclohexanone oxime is produced in the synthesis section [I] of cyclohexanone oxime. In the synthesis section [I] of cyclohexanone oxime, an aqueous medium containing hydroxylammonium and inorganic ions prepared in water is contacted with an organic medium containing cyclohexanone and an organic solvent, preferably toluene. In the synthesis section [I] of cyclohexanone oxime, hydroxylammonium reacts with cyclohexanone to form cyclohexanone oxime. The aqueous medium and the organic medium are supplied to the synthesis unit [I] of cyclohexanone oxime via lines [1] and [2], respectively. The resulting aqueous layer was discharged from the synthesis portion [I] of cyclohexanone oxime via line [3].

The organic product solution containing cyclohexanone oxime and cyclohexanone dissolved in an organic solution (toluene) is discharged from the cyclohexanone oxime [I] at the discharge level of the organic product solution via line [4]. This organic product solution, which contains some water, hydroxylammonium, and inorganic ions, is supplied to the liquid-liquid separator [II] via line [4B], and/or to the liquid-liquid mixing section via line [4A] [ III]. In the liquid-liquid separator [II], an organic top layer and an aqueous underlayer are formed. The aqueous bottom layer is discharged from the liquid-liquid separator [II] via line [5]. Preferably, this aqueous underlayer is supplied to the synthesis section [I] of cyclohexanone oxime. The organic top layer is discharged via line [6] and supplied to the liquid-liquid mixing section [III].

The liquid-liquid mixing section [III] may contain a stirrer and/or a static mixer, preferably a stirrer. Water or an aqueous solution, preferably demineralized water or an aqueous NH3 solution, is supplied to the liquid-liquid mixing section [III] via line [7]. The aqueous medium and the mixture of the organic medium are discharged from the liquid-liquid mixing portion [III] via line [8], and supplied to the liquid-liquid separator [IV]. In the liquid-liquid separator [IV], an organic top layer and an aqueous underlayer are formed. The aqueous bottom layer is discharged from the liquid-liquid separator [IV] via line [9]. Optionally, to make the liquid-liquid separator [IV] One part of the aqueous underlayer was supplied to the liquid-liquid mixing portion [III] via the line [9A], and the remaining portion was discharged to the synthesis portion [I] of the cyclohexanone oxime via the line [9B].

The organic top layer is discharged via line [10]. The organic top layer, which contains some remaining water, hydroxylammonium, and inorganic ions, is directly discharged to the cyclohexanone oxime recovery section via line [10A], wherein a product mainly comprising cyclohexanone oxime is obtained, or is introduced into the ring The hexanone oxime recovery unit can be fed into the liquid-liquid separator [V] via line [10B]. In the liquid-liquid separator [V], an organic top layer and an aqueous underlayer are formed. The aqueous bottom layer is discharged from the liquid-liquid separator [V] via line [12]. Preferably, this aqueous underlayer is supplied to the synthesis section [I] of cyclohexanone oxime.

Figure 3: (See also Figure 1 and Figure 2) Recleaning process

The organic top layer from the liquid-liquid separator [IV] is fed into the liquid-liquid mixing section [III ^a ] via line [10]. Water or an aqueous solution is fed into the liquid-liquid mixing section [III ^a ] via line [14]. Optionally, the aqueous solution derived from the liquid-liquid separator [IV ^a ] and/or the aqueous solution derived from the liquid-liquid separator [V ^a ] are fed separately via lines [13A] and [17A], respectively In the liquid-liquid mixing section [III ^a ]. The water and/or aqueous solution is mixed with the organic top layer in the liquid-liquid mixing section [III ^a ], and the obtained mixture is introduced into the liquid-liquid separator [IV ^a ] via line [15]. The top layer of the organic water-soluble base, in a liquid - liquid separator to separate [IV ^a], and in that the water-soluble base, [13] from the liquid via line - discharging liquid separator [IV ^a] in. A portion of the aqueous bottom layer is fed back to the liquid-liquid mixing portion [III ^a ] via line [13A], and the remaining portion is introduced into the liquid-liquid mixing portion [III] via line [13B], and/or via a pipeline. [13C] is introduced into the synthesis section [I] of the crucible, and/or disposed of via the line [13D]. The organic top layer of the liquid-liquid separator [IV ^a ] was discharged through line [16], and then directly introduced into the cyclohexanone oxime recovery section via line [16A]. The organic top layer of the liquid-liquid separator [IV ^a ] may also be introduced into the liquid-liquid separator [V ^a ] via line [16B] to separate the water or aqueous solution contained in the organic top layer. The aqueous bottom layer of the liquid-liquid separator [V ^a ] is introduced into the synthesis section [I] of cyclohexanone oxime via the line [17C], and/or introduced into the liquid-liquid mixing section [III] via the line [17B]. (Fig. 1), and/or introduced into the liquid-liquid mixing section [III ^a ] via line [17A], and/or disposed via line [17D]. The organic top layer of the liquid-liquid separator [V ^a ] was directly introduced into the cyclohexanone oxime recovery section via line [18], and a product mainly containing cyclohexanone oxime was obtained.

Figure 4 shows an overview of the purification of cyclohexanone oxime dissolved in an organic medium comprising two re-cleaning steps. See Figure 3 for a detailed description.

The invention will be further described in the following non-limiting examples.

Example 1 (see Figure 1)

In a device using the technology in the DSM HPO ^®, was dissolved by toluene and cyclohexanone dissolved in an aqueous solution containing the reaction of hydroxyl ammonium phosphate, the continuous production of cyclohexanone oxime. The organic product solution (toluene/cyclohexanone turbulent flow) obtained from the top of the synthesis section [I] of cyclohexanone oxime is sent to the liquid-liquid mixing section [III], liquid-liquid separator [IV] And a cleaning unit composed of a liquid-liquid separator [V]. The liquid-liquid mixing section [III] is composed of a cylindrical mixing box and is equipped with a turbine agitator. The organic product solution (toluene/cyclohexanone oxime mixture), fresh demineralized water, and an aqueous recycle stream are fed into the liquid-liquid mixing section [III]. The liquid-liquid mixing section [III] is operated in the form of an organic phase as a continuous phase. The liquid-liquid separator [IV] is composed of a gravity settling tank and is equipped with four baffles. The obtained aqueous underlayer is divided into a portion which is sent to the synthesis portion [I] of cyclohexanone oxime, and a portion which is returned to the liquid-liquid mixing portion [III]. The obtained organic top layer is sent to a liquid-liquid coalescer [V] having glass fibers as a coalescing medium. The aqueous underlayer recovered from the coalescer [V] is sent to the synthesis section [I] of cyclohexanone oxime.

The conditions of the purification section of cyclohexanone oxime dissolved in toluene (average of stable cyclohexanone oxime production during 24 hours) are:

The aqueous phase back to the cyclohexanone oxime reactor contains:

Phosphate recovery: 61% by weight.

Example 2 (see Figure 2)

In a device using the technology in the DSM HPO ^®, was dissolved by toluene and cyclohexanone dissolved in an aqueous solution containing the reaction of hydroxyl ammonium phosphate, the continuous production of cyclohexanone oxime. The organic product solution (toluene/cyclohexanone turbulent flow) obtained from the top of the synthesis section [I] of cyclohexanone oxime is sent to the liquid-liquid mixing section [III], liquid-liquid separator [IV] And a cleaning unit composed of a liquid-liquid separator [V]. The liquid-liquid mixing section [III] is composed of a cylindrical mixing box and is equipped with a turbine agitator. An organic product solution (toluene/cyclohexanone oxime mixture) recovered from the liquid-liquid separator [IV], fresh demineralized water and an aqueous phase, and an aqueous phase recovered from the coalescer [V], fed into the liquid - in the liquid mixing section [III]. The liquid-liquid mixing section [III] is operated in the form of an organic phase as a continuous phase. The liquid-liquid separator [IV] is composed of a gravity settling tank and is equipped with four baffles. The obtained aqueous underlayer is divided into a portion which is sent to the synthesis portion [I] of cyclohexanone oxime, and a portion which is returned to the liquid-liquid mixing portion [III]. The obtained organic top layer is sent to a liquid-liquid coalescer [V] having glass fibers as a coalescing medium. The aqueous phase recovered from the coalescer [V] is sent to the liquid-liquid mixing section [III].

The conditions of the purification section of cyclohexanone oxime dissolved in toluene (average of stable cyclohexanone oxime production during 24 hours) are:

The phosphate concentration in the toluene/cyclohexanone turbulent stream leaving the top of the cyclohexanone oxime reactor was about 828 ppm (weight/weight). The purified toluene/cyclohexanone turbulent stream obtained from the coalescer contained about 284 ppm (weight/weight) phosphate. Due to the purification of this toluene/cyclohexanone oxime, about 20 kg of phosphate can be recovered per hour.

Example 3 (refer to Figure 4)

The cyclohexanone oxime in the purified toluene/cyclohexanone turbulent stream recovered in the coalescer [V] was further purified by re-cleaning (see Example 2). This re-cleaning consists of a liquid-liquid mixing section [III ^a ], a liquid-liquid separator [IV ^a ], a liquid-liquid mixing section [III ^b ], a liquid-liquid separator [IV ^b ], and a coalescer [V ^b ] constitutes. The liquid-liquid mixing section [III ^a ] is composed of a cylindrical mixing box and is equipped with a turbine agitator. An organic phase (toluene/cyclohexanone oxime mixture) recovered from the coalescer [V], an aqueous bottom layer of the liquid-liquid separator [IV ^b ], an aqueous underlayer recovered in the coalescer [V ^b ], and The aqueous bottom layer recovered in the liquid-liquid separator [IV ^a ] is fed into the liquid-liquid mixing portion [III ^a ] via the lines [11], [21B], [23], and [13A]. Both the liquid-liquid separators [IV ^a ] and [IV ^b ] are composed of gravity settling tanks. The aqueous underlayer obtained in the liquid-liquid separator [IV ^a ] is divided into a portion which is returned to the liquid-liquid mixing portion [III ^a ] via the line [13A], and a portion which is disposed via the line [13B]. The organic top layer obtained in the liquid-liquid separator [IV ^a ] is sent to the liquid-liquid mixing section [III ^b ] via line [16]. The liquid-liquid mixing section [III ^b ] consists of a series of static mixers connected in series. In this section, the organic phase is mixed with fresh demineralized water via line [19] and an aqueous recycle stream. The obtained mixture was fed into a liquid-liquid separator [IV ^b ] via a line [20]. The aqueous bottom layer obtained in the liquid-liquid separator [IV ^b ] is divided into a portion sent to the liquid-liquid mixing portion [III ^a ] via the line [21B], and returned to the liquid-liquid via the line [21A]. Part of the mixing section [III ^b ]. The obtained organic top layer is sent via line [22] to a coalescer [V ^b ] having glass fibers as a coalescing medium. The purified toluene/cyclohexanone oxime stream recovered in the coalescer [V ^b ] is sent to the distillation section via line [24] to separate cyclohexanone oxime and toluene. The obtained cyclohexanone oxime can be used to produce ε-caprolactam.

The conditions of the purification section of cyclohexanone oxime dissolved in toluene (average of stable cyclohexanone oxime production during 24 hours) are:

Due to the purification of this toluene/cyclohexanone oxime, about 7 kg of phosphate can be recovered per hour. Therefore, the purified toluene/cyclohexanone turbulent stream obtained by feeding into the distillation section is almost free of phosphate.

1, 2, 3, 4, 7, 8, 9, 9A, 9B, 10‧‧‧ pipelines

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III‧‧‧Liquid-Liquid Mixing Department

IV‧‧‧Liquid-Liquid Separator

Claims (21)

A continuous process for purifying a solution of an organic product comprising hydrazine dissolved in an organic medium, the method comprising: (1) discharging the organic product solution from the synthesis section [I] of the hydrazine to the liquid-liquid mixing section [ (3) mixing the organic product solution with water and/or an aqueous solution, and then discharging the resulting mixture to a liquid-liquid separator [IV]; (3) at the liquid-liquid separator [IV] The organic top layer separated from the produced aqueous bottom layer, and the organic top layer is introduced into the helium recovery portion; (4) the aqueous bottom layer of the liquid-liquid separator [IV] is fed into the synthesis unit of the crucible In [I], a part of it is optionally fed back to the liquid-liquid mixing section [III]. The method of claim 1, wherein in the step (4), a part of the aqueous underlayer is introduced into the liquid-liquid mixing portion [III], and the remaining portion is sent to the synthesis portion of the crucible [I] in. The method of claim 2, wherein at least 80% by weight of the aqueous underlayer is introduced into the liquid-liquid mixing portion [III]. The method according to any one of the preceding claims, wherein the aqueous medium contained in a portion of the organic product solution is subjected to liquid-liquid separation before the organic product solution is introduced into the liquid-liquid mixing portion [III]. Separated in [II]. A method according to any one of the preceding claims, wherein from step (3) The organic top layer obtained therein is introduced into the liquid-liquid separator [V] before being introduced into the helium recovery section. The method of any one of the preceding claims, wherein the organic top layer obtained from the step (3) is subjected to at least one re-cleaning process before being introduced into the helium recovery portion. The method of claim 6, wherein the organic top layer obtained from the step (3) is subjected to a treatment of two re-cleaning processes before being introduced into the crucible recovery unit. The method of claim 6 or 7, wherein the re-cleaning process comprises: (i) introducing an organic top layer of the liquid-liquid separator [IV] into the liquid-liquid mixing section [III ^a ], and Mixing the organic top layer with water and/or an aqueous solution; (ii) discharging the resulting mixture from the liquid-liquid mixing section [III ^a ] to the liquid-liquid separator [IV ^a ], and separating from the produced aqueous bottom layer The organic top layer produced; (iii) introducing part or all of the aqueous bottom layer of the liquid-liquid separator [IV ^a ] into the synthetic portion [I] of the crucible, and/or introducing the liquid-liquid mixing portion [ In III], and/or introduced into the liquid-liquid mixing section [III ^a ], and/or disposed of; (iv) introducing the organic top layer of the liquid-liquid separator [IV ^a ] into the crucible recovery section. The method of claim 8, wherein the aqueous bottom layer of a portion of the liquid-liquid separator [IV ^a ] is returned to the liquid-liquid mixing portion [III ^a ]. For example, the method of claim 6 of the patent scope, wherein each re-cleaning process A portion or all of the aqueous bottom layer of one of the liquid-liquid separators is introduced into the combined portion [I] of the crucible and/or any one or more of the previous liquid-liquid mixing portions, and the remaining portion is disposed of. The method of claim 6, wherein the organic top layer obtained from each re-cleaning process is introduced into the liquid-liquid separator before being introduced into the next re-cleaning process. The method of claim 11, wherein the liquid-liquid separator is a coalescer. The method of claim 11, wherein a part or all of the aqueous underlayer is obtained in the liquid-liquid separator, introduced into the synthetic portion [I] of the crucible, and/or any one or more of the preceding liquids - In the liquid mixing section, the remaining portion is disposed of. The method of claim 8, wherein an aqueous bottom layer of more than 80% by weight of the liquid-liquid separator [IV ^a ] is fed into the liquid-liquid mixing portion [III ^a ]. The method of claim 8, wherein the liquid-liquid separator [IV ^a ] organic top layer is sent to the liquid-liquid separator [V] before being introduced into the helium recovery unit. The method of claim 5, wherein the liquid-liquid separator [V] is a coalescer. The method of claim 1, wherein the aqueous solution comprises demineralized water and/or vapor condensed water. The method of claim 1, wherein the liquid-liquid separator [IV] is a gravity liquid-liquid settling tank. The method of claim 1, wherein the oxime is cyclohexanone oxime. The method of claim 1, wherein the temperature in the liquid-liquid mixing portion [III] is in a range from 30 to 90 °C. The method of claim 1, wherein the organic medium is toluene.