DD140349A1 - PROCESS FOR THE PRODUCTION OF ACETONE OXIM - Google Patents

Abstract

The invention relates to a process for the preparation of Acetone oxime by reaction of acetone with salts of Hydroxylamine. The aim of the invention was the development of a economically favorable process, that at stoichiometric Use of reactants enables high sales and at the same time the complete separation of the formed acetone oxime from the Reaction mixture without the addition of foreign excipients with relative low energy consumption allowed. After the invention Method, which by the two-stage reaction under Compliance of given molar ratios of the reactants in the first and their stoichiometric use in the second reaction stage as well as after the first and second stages Separation of the acetone oxime formed from the reaction mixture can acetone oxime in technical and technologically simple way and good yields are obtained.

Description

2 0 9701- ^

LP 78101

Title of the invention

Process for the preparation of acetone oxime. Field of application of the invention

The invention relates to a process for the preparation of acetone oxime by reacting acetone with salts of hydroxylamine.

Characteristic of the known technical solutions

Bs is known to produce acetone oxime by reaction of hydroxylammonium salts with acetone with simultaneous neutralization of the thus liberated acid. The oximation reagents used are both pure hydroxyammonium salts and their technical solutions, as described, for example, in US Pat. obtained in the production of hydroxylamine Raschig used. The. Reaction can be carried out both in aqueous solution and in other media, such as liquid ammonia (Berdtsch., Ges. 1_5 (1882) 1324, J. Amer. Chem. Soc., 45 (1923) 189, US Pat 2 257908). Furthermore, it is known that the separation of the acetone oxime from the reaction solution by distillation, extraction or phase separation can be carried out (DE-PS 1,131,203, DD-PS 123 439). While the extraction involves the use of non-process substances and the

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Halation requires a relatively high energy expenditure, there are the disadvantages of the sole application of the phase separation in the associated high material losses and the restriction to reaction mixtures with high salt concentration. In addition, it is known that the equilibrium in the oximation of acetone, depending on the pH, to some extent on the side of the reaction product, but with stoichiometric use of the reactants, no complete conversion is achieved. The reaction is therefore often carried out in this way in that one of the two components is used in excess, is disadvantageous in that the use of an excess product causes material losses or aufv / endige reclamation operations.

Object of the invention

The aim of the invention is to make the production of acetone oxime more economical.

Statement of the invention

The object was to develop a process for the production of acetone oxime which, with stoichiometric use of the reactants, permits high conversions and at the same time permits the complete removal of the acetone oxime formed from the reaction mixture without the addition of external auxiliaries with relatively low expenditure of energy.

This object is achieved by a process for the preparation of acetone oxime from acetone and salts of the hydroxylamine according to the invention in that the reaction takes place in two stages, wherein the reaction in the first reaction stage at an acetone / hydroxylamine molar ratio of 0.5 to 0.95, preferably 0 , 8 to 0.9 ·), the further reaction in the second reaction stage after complete or partial separation of the acetone oxime formed with the stoichiometric amount of acetone required for oxime formation from the unreacted hydroxylammonium salts, the organic phase of the

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thereby obtained Reaktionsgemische_s combined with the separated in the first reaction stage acetone oxime, while the aqueous phase is subjected to distillation and the acetone oxime-containing distillate combined with the separated in the first reaction stage acetone oxime or a separate workup or use is supplied. The temperature chosen for the oximation is without significant influence on • their implementation of the invention, but should be kept suitably between 308 and 323 K, on the one hand, the crystallization of the deposited organic phase when using highly concentrated salt solutions and on the other hand, the discharge of the low-boiling acetone from the reaction system prevent. Of course, the required temperature is also determined by the residence time which can be varied within wide limits. Essential for the "reaction is the good mixing of the two-phase reaction mixture, which can be achieved by a number of technical processes for phase distribution." In practice, the use of stirred vessels has proved to be an equally simple and effective procedure Formation of acetone oxime usual pH range of 5 to 7 can deviate with application of the procedure according to invention toward lower pH values, without causing substantial yield losses.It is a special advantage of the procedure according to invention that despite stoichiometric relation of the input products reaches their almost complete conversion where the approximation to the ideal case depends both on the pH, which determines the equilibrium of the reaction, and on the molar ratio of acetone / hydroxylamine in the first reaction stage The overall yield of acetone oxime increases with increasing acetone / hydroxylam ratio in the first reaction stage, and reaches 0.8 to 0.9, the working range for carrying out the process according to the invention, particularly good values. In the choice of the molar ratio, however, the extent of the separation of the acetone oxime formed in the first reaction stage must be taken into account before further reaction. The

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bene case refers to a degree of separation of 80 to 90%, as it is achieved when using conventional technical hydroxylammonium sulfate solutions for oximation and use of the phase separation to separate the oxirane formed. The partial or complete separation of the acetone oxime formed in the first reaction stage before the further reaction 'is absolutely necessary for carrying out the reaction according to the method. The separation can be carried out both virtually completely by distillation or extraction and incomplete by phase separation. Although the complete separation has proven to be particularly favorable for some application examples in the sense of the method according to the invention, the phase separation is generally preferable for economic reasons. The separation of the acetone oxime formed by phase separation after the second reaction stage is not absolutely necessary, but has proved to be useful in order to simplify the subsequent distillation and to make it more economical. ... For the usual use of aqueous solutions in various applications, the three acetonoximhaltigen products of a common further processing can be supplied. Is a low-water or -frei product needed, it is convenient? The separation of the acetone oxime in the first stage reaction by phase separation or extraction and to unite with the organic phase of the second reaction stage, · during the workup of the distillate as an aqueous solution takes place, since with extraction of this product with relatively high solvent losses must be expected.

embodiments

Example 1 . ,

An apparatus consisting of two successively connected + thermostatted stirred vessel (capacity about 2.3 l) and separators and a continuously operated distillation column (diameter: 40 mm, height: sub-column: 610 ram, top column + systems.

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380 mm; Filling: Berlsättel 4x4 mm), every hour 159i6 g of acetone

1 961.8 g of technical hydroxylammonium sulfate solution of the composition.

Hydroxylammonium sulfate 11.5 Ma .% Sulfuric acid 8.6 Ma. # Ammonium sulfate. 26.9 Ma.-JS water. 53.0 Ma. -%

fed. The amount of acetone is divided so that 146.4 g of acetone per hour are metered into the first stirred vessel. The reaction in the first stirred vessel takes place at 318 K and pH 6, for the adjustment of which 402.2 g / h of aqueous solution of ammonia 25 are required. The residence time in the first stirring vessel is about 30 min. ·

The continuously. Removed reaction mixture passes to the phase separation in the subsequent separator; The acetone <0.1 Ma. % Acetone oxime 87.8 »-% water 12.2

containing organic phase (176.2 g / h) is from the process + while the aqueous phase (2334.2 g / h) of the composition; , · Acetone traces

Acetone oxime 1.2 Ma. ~%

Hydroxylammonium sulfate · 0.8 Ma .- # Ammonium sulphate 39.5 Ma. -%

V / asser 58.5 Ma.-JS

in the second stirred vessel at 313 K and the adjusted by addition of 18.4 g / h of 25 % aqueous ammonia solution pH is reacted with 13.2 g / h of acetone. The residence time in the second stirred vessel is about 30 minutes. The reaction mixture passes to the phase separation in a separator. During the organic phase (23.4 g / h), the composition '

Acetone oxime 87.4 Ua, -% · acetone 0.2 Ma. -% water 12,4 Ma. -%

leaves the process, the aqueous phase (2358.2 g / h) of the composition

+ taken out _f

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Acetone oxime 1.2% by mass

Acetone traces;

Ammonium sulphate 39.9 Ma .- ^ Water 58.9 Ma .- #

fed to the already described distillation column. At a reflux ratio of 1 are hourly 83.2 g Destil latider composition

Acetone oxime 29.9% by weight acetone; 0.1 Ma. -% water. 70.0 Ma, -5S.

receive. ,

The yield of acetone oxime is 99.6 % of theory.

Example 2

An apparatus, according to example .1, become hourly

79.8 g of acetone 980.9 g of technical hydroxylammonium sulfate solution

Composition according to Example 1

fed. The amount of acetone is divided so that the first stirrer hourly 73.2 g of acetone zudosi.ert be. The reaction in the first stirred vessel takes place at 3.13 K and pH 4, for the adjustment of which 202.6 g / h of 25% aqueous ammonia solution are required. The residence time in the first stirred vessel is about 1 h. The continuously removed reaction mixture passes to the phase separation in the separator. The acetone 0.1% by mass

Acetone oxime 87.6 Ma. -%

Water 12.3 Ma. -% _m

containing organic phase (90.6 g / h) is led out of the Proz-eß, while the aqueous phase (1 166.1 g / h) of the composition · · '

Acetone traces.

Acetone oxime. 1.1% by mass. · Hydroxylammonium sulfate at .0.8 Ma.-fo

Ammonium sulphate 39.5Ma .-%

Water 58.6 Ma, -%

in the second stirred vessel at 313 K and by adding 7.1

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25 J & iger aqueous ammonia solution adjusted pH 4 is reacted with 6.6 g / h of acetone. The residence time in the second stirred vessel is about 1 h. The reaction mixture passes to the phase separation in a separator. While the organic phase (9.9 g / h) of the composition

Acetone 0.6% by mass

Acetone oxime 87.1 ha.%

Water 12.3 Ma.-SS

leaves the process, the aqueous phase (11 69.9 g / h) of the composition

Acetone «£ 0.1 Ma. -%

Acetone oxime 1.0 Ma. -%

Hydroxylammonium sulfate 0.1 Ma .- ^

Ammonium sulfate 39.9 Ma.-JS ''

Water · 59,0 Ma.-JS

the im. Supplied to Example 1 distillation column. At a reflux ratio of 1 per hour 38.5 g of distillate of the composition

Acetone oxime 29.6 Ma. -%

Acetone 1.4 Ma. -% '"

Water 69.0 Ma ..- # received

The yield of acetone oxime is 99.1 % of theory.

Example 3 (comparative example)

An apparatus consisting of a thermostatted stirred vessel (capacity 1.1 1) with a separator and a continuously operated distillation column according to Example 1 are hourly

79.8 g of acetone

  980.9 g technical Hydroxylammoniumsulfatlösung supplied with the composition according to Example 1.

The reaction in the stirred vessel is carried out at 313 K and a pH of 4, for 'setting 205.5 g / h 25 # aqueous ammonia solution

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required are,. The residence time in the Ruhr vessel is about 1 h. ".

The continuously discharged reaction mixture passes to the phase separation in the separator. , The acetone. 2.5 Ma. -%

Acetone oxime 87.0 Ma, -JS '. , ·

Water 10.5 .m.-Jg ''

containing organic phase (92.8 g / h) is carried out from the process ago., While the aqueous phase (11 73.4 g / h) of the composition

Acetone 0.2% by mass

Acetone oxime 1.2% by mass

Hydroxylammonium sulfate 0.5 Ma. -% .

Ammonium sulfate 39.5 % by mass

Water 58.6% by mass. , ,

the distillation column described in Example 1 is supplied. At a reflux ratio of 1 v / hour, 50.9 g of distillate of the composition are produced every hour

Acetone 4.0 % by mass .

Acetone oxime 28.3 Ma .- ^

Y / asser 67.7 Ma.-SS

 receive

The yield of acetone oxime is 94.6 % of theory.

Claims (2)

· - 9 Claim for invention 2 0 9701 A process for the preparation of acetone oxime from acetone and salts of hydroxylamine, characterized in that the reaction in two /; Steps are carried out, wherein the reaction in the first reaction stage at a molar ratio acetone / hydroxylamine of 0.5 to 0.95, preferably 0.8 to 0.90, carried out, the further reaction in the second reaction stage, after complete or partial separation the resulting acetone oxime is stoichiometrically required with the amount of acetone required for oxime formation from the unreacted hydroxylammonium salts, the organic phase of the resulting reaction mixture is combined with the acetone oxime separated in the first reaction stage, while the aqueous phase is subjected to distillation and the acetonoxime-containing distillate is esterified with the acetone oxime separated in the first reaction stage, or fed to a separate work-up or use.