FI117598B - Synthesis of azine(s) - by reacting hydrogen peroxide and a carbonyl contg. reactant with ammonia and a low acidity amide plus an ammonium salt - Google Patents

Abstract

Synthesis of azines uses H2O2 ammonia and a reactant with a CO gp. It is effected by contacting these prods. with an amide of low acidity and the NH4 salt corresp. to the acid from which the amide is derived. The azine is sepd. from the reaction mixt. Pref. the reactant contg. a CO gp. is generally an aldehyde or ketone, pref. the latter and more specifically acetone, methyl, ethyl, ketone or methyl isobutyl ketone. R1 and R2 may be alkyl 1-12C, aromatic 6-12C, Cl-NO2 or CH3O etc. The amide is selected from acetamide-propionamide n-butyramide and iso-butyramide.

Description

* 117598

Azin Synthesis Process - Azinernas Synthesis Process This application is a division of FI-915514.

The present invention relates to a process for the synthesis of azines and their use in the preparation of hydr-5 azines. Hydrazine, most often in the form of hydrazine hydrate, is a widely used substance either as such or as an intermediate in the synthesis. According to ULLMANN1N - 5th Edition 1989 - Volume A 13, pages 177 -191, hydrazine is prepared either by oxidation of ammonia with chlorine or sodium hypochlorite solution, possibly.

as an intermediate, ketamine, or by reaction of hydrogen peroxide, ammonia, and ketone.

The essential features of the invention are set forth in the appended claims.

t

The present invention relates to a hydrogen peroxide process; it has been described in numerous patents, especially US-3,972,878, US-3,972,876, US-3,869,541, US-3,948,902, US-3,919,256, US-3,943,152, US-4,093,656.

According to this method, ammonia, hydrogen peroxide and a compound having the group C = O, such as a ketone, are reacted with each other, which may be represented. . / • · · using the following equation: • · · • · · Γ *: 20 Ri Rl Ri "* *! * · *. \ \ /:. · * 2NH3 + 2 C - O + H202 -» C = N- N-C + 4 H2O 1: '** / / 0': r2 r2 r2 25: The reaction is carried out in the presence of a catalyst.

The azine can then be hydrolyzed to the hydrazine hydrate according to the equation: * ·: R 1 R 1 R 1 O /: \ 30 C = N- N = C + 3 H 2 O 2 • C = O + N2H4, HoO "**; / \ / * · * · *: R2 R2 R2 regenerating ketone.

2 117598

U.S. Pat. No. 3,972,878 describes a reaction in the presence of a mixture of a weak acid amide and phosphate. For example, acetamide with lithium phosphate, acetamide with sodium carbonate, propionamide with lithium phosphate, acetamide with disodium phosphate, acetamide with diisopropyl phosphate have been used.

The yield of azine based on hydrogen peroxide ranges from 45% to 55% and rises to 78% with a pair of acetamide and disodium phosphate.

U.S. Pat. No. 4,093,656 also discloses a catalyst for use in the synthesis of azines, which is a mixture of three compounds, namely a weak acid amide, the corresponding ammonium salt, and another compound such as phosphate. For example, acetamide, ammonium acetate and sodium phosphate have been used. The yield of azine based on hydrogen peroxide rises to 85%. Substantial simplification has now been found since the same yield is observed when using either a catalyst consisting of a mixture of a weak acid amide, a corresponding ammonium salt and a compound such as phosphate, or a catalyst consisting of a mixture of a weak acid amide and the corresponding ammonium salt.

The present invention thus relates to a process for the synthesis of azines starting with hydrogen. : peroxide, ammonia, and carbonyl-containing reactant and · *. · [The process is characterized by contacting these reactants with a weak · · · acid amide and the corresponding ammonium salt, and then separating • · '; 20 retrieved atsini.

• * · 'i • · - -i t ·

Hydrogen peroxide can be used in a conventional commercial form, for example as an aqueous solution containing 30-90% by weight of H2O2. Preferably one or more conventional peroxide solution stabilizing agents may be added, for example sodium salt of ethylenediaminetetraacetic acid. The ammonia may be dry or in aqueous solution.

• · · * · This carbonyl-containing reactant has the formula «C: r! wherein R 1 and R 2, identical or different, represent hydrogen, an alkyl group of 1 to 12 carbon atoms, a branched alkyl group or a cycloalkyl of 3 to 12 carbon atoms; 12 carbon atoms, aromatic group having 6-12 carbon atoms, or together represent a straight-chain or branched alkylene group having 3-12 carbon atoms; wherein the substituents may be halogen, a NC2 group, a hydroxy, an alkoxy or a carboxyl ester and preferably C1, NO2 or CH3O.

Reactive substances

Rl 5 \

C/O

Examples of / R 2 'are aldehydes or ketones.

Among the aldehydes, mention may be made of formaldehyde, acetaldehyde, butyl aldehyde, isobutyl aldehyde, n.pentanal, pivalaldehyde, benzaldehyde, monochlorobenzaldehyde; hydroxy, paranitrobenzaldehyde, anisaldehyde, betachloropropionaldehyde, beta-methoxypropionaldehyde.

Among the ketones may be mentioned acetone, 2-pentanone, 3-pentanone, methyl isopropyl-ketone, methyl isobutyl ketone, methyl ethyl ketone, methyl cyclohexyl ketone, acetophenone, benzophenone, cyclobutanone, cyclopentanone, cyclohexanone.

Preferably, ketones wherein K 1 and R 2 are identical or different and are ·· * linear or branched alkyl groups having 1 to 5 carbon atoms, and preferably acetone, methyl ethyl ketone and methyl are used. -isobutyyliketonia. The reactants may be used in stoichiometric amounts, but may be used: 0.2 moles of hydrogen peroxide per mole and preferably 1.5 to 4 moles of the reactive carbonyl compound (aldehyde or ketone). and 0.1 to 10 moles and preferably 1.5 to 4 moles **. excess ammonia.

The amides of the present invention are derived from the corresponding carbonic acids having a dissociation constant of less than 5 x 10 3, i. acids having a PK greater than 4.3 in aqueous solution at 25 ° C. '1 • · · * ·

Of polycarboxylic acids they are those with a first ionization constant of *: **. * Smaller than 5 x 10A

By way of example, mention may be made of carbonic acids of the formula R 5 COOH, where R is a straight chain alkyl group of 1 to 20 carbon atoms or a branched or cyclic alkyl group of 3 to 12 carbon atoms, or a phenyl group which may be substituted, polycarboxylic acids of formula <5 (COOH) n representing the alkylene group, h., 17598 having 1 to 10 carbon atoms and n having a value of 1 or 2 can be a single bond and · *! then the brain of n is 2. The groups R 5 and R 8 may be substituted with halogens, stupid OH, NO 2 or methoxy. Acetamide, propionamide, n-butylamide or isobutylamide are preferably used.

The aminonium salt corresponding to acetamide is aminonium acetate.

It would not be excluded from the invention if an ammonium salt is formed in situ, i. using the corresponding carboxylic acid which reacts with the ammonia to give the ammonium salt.

The ratio of the amide to the corresponding ammonium salt may vary within wide limits. ? Usually 1-25 parts of ammonium salt are used per 5 parts of amide and preferably 2-10 parts.

The amount of amide can vary within wide limits.

The contacting of the hydrogen peroxide, ammonia, and carbonyl group reactant with the amide and ammonium salt can be accomplished in any manner.

* * ♦ * * * ♦ Γ / Preferably, work in a homogeneous medium or medium that can at least guarantee sufficient solubility of the reactants to obtain *; ; * download. The reaction can be carried out at a very wide temperature range, for example, between about 30 ° C and about 100 ° C, and preferably between 30 ° C and 70 ° C. Although 5 '· * 20 square at any pressure may be employed, it is simpler to be at atmospheric pressure, V ·, but the pressure may be increased to about 10 bar if necessary to maintain the reaction preferably in the liquid phase.

• · *

The reactants may be introduced simultaneously or separately and in any order. Any type of reactor can be used, either agitated * *: * ·· 25 or non-agitated, or even of simple capacity that can be installed in parallel, in series, downstream, or countercurrent, or any combination of these.

Amide and the ammonium salt are usually used in the form of an aqueous solution.

This solution may also contain alcohol. Of the alcohols, aliphatic saturated alcohols having 1 to 6 carbon atoms and preferably 1 to 2 carbon atoms are preferably used.

- 5: 117598 Diols are also preferably used, especially diols having from 2 to 5 carbon atoms. For example, glycol, propylene glycol, 1,3-propanediol, 1,3- and 1,4-butanediol and 1,5-pentanediol may be mentioned.

At the end of the reaction, azine can be recovered by distillation, liquid-liquid extraction, or any equivalent method, or even completely or partially by simple decantation if insoluble in the reaction medium.

After the azeine is recovered from the reaction mixture, a solution remains which contains the amide and the ammonium salt and optionally ammonia, a carbonyl-containing reactant, hydrogen peroxide and various by-products or impurities.

Ammonia and the carbonyl-containing reactant are recovered as much as possible so that they are preferably recycled to the ring for the synthesis reaction.

The invention has the advantage of avoiding the use of substances such as phosphates which complicate the post-treatment of the solution of the amide and the ammonium salt. Hydrogen peroxide is difficult to return to the cycle; working under conditions where it is consumed completely.

Regardless of whether the synthesis of the azines is performed (i) in the presence of the weak acid amide and the corresponding ammonium salt as described above, or (ii) in the presence of the weak acid amide, the corresponding ammonium salt and a compound such as phosphate * *, as described in U.S. Pat. or (iii) in the presence of a weak acid * · · · · · 20 amide and a compound such as phosphate, as disclosed in U.S. Pat. No. 3,972,878, the present invention also relates to treatment of solutions containing these compounds to cycle for synthesis of azines - • \ # oxide, ammonia and carbonyl-containing reactant.

• • · «• ♦ · ·

Thus, the present invention also relates to a process for the synthesis of azines from hydrogen peroxide, ammonia, and a reactant containing a carbonyl compound, and the process is characterized in that these reactants are contacted with a mixture of contains weak: I *. c) treating the mixture by heating at a temperature between 170 ° C and 230 ° C to recover the original amount of amide present in step a) *: **: d) recovering the mixture obtained at the end of step c) to step a).

117598 6

The reactant containing the carbonyl group is the same as described above. The amide-containing mixture is one of the three mixtures described above, i. it also contains a compound, which may also be a phosphate as disclosed in US-3,972,878, or further comprising the corresponding ammonium salt as disclosed in US-4,093,656, or it is a mixture of a weak acid amide and the corresponding ammonium salt , as presented at the beginning of this text.

It has been found that part of the amide of step a) had been converted to the corresponding ammonium salt, i.e. that if acetamide is introduced in step a), acetamide and ammonium acetate are obtained.

As after the above step a) of the synthesis, azine is recovered in step b) and a solution containing a portion of the introduced amide and its corresponding ammonium salt remains. The number of moles of amide remaining plus the number of moles of the corresponding ammonium salt is nearly equal to the number of moles of amide introduced in step a). This solution also contains the compound which was present at the beginning of step a) with the amide, this compound may be the corresponding ammonium salt or phosphate or a mixture of both (salt and phosphate), i.e. if acetamide and phosphate were present at the beginning of the reaction , ammonium acetate ·. : and phosphate solution. If acetamide and acetate were present at the beginning of step a), a solution * · «with less acetamide and more acetate was obtained. If at the beginning of step a) there were acet * * * * ". · 20 amides, acetate and phosphate, a solution containing less acetamide, · · * *; f more acetate and phosphate is obtained. This solution may also contain, after the reactant has been removed, impurities and excess reactants: ammonia: *** and carbonyl-containing reactant. It is preferable to recover these excess reactants, followed by step c), i.e., the amino acid salt is converted to the corresponding amide until the original amide of step a) is regenerated. One preferred means is, for example, simple heating. This reaction is known. When heating is carried out in step c), the ammonium salt is then converted to the amide 9 · Amide-containing mixture of step a) This reaction may also be followed by the decomposition of a portion of the · · · · 30 ammonium salt into ammonia and to the corresponding acid.

• · ·

«II

The ammonia and the acid are mixed again to re-form the ammonium salt, which is returned to the cycle.

If the reconstituted mixture for carrying out step a) is a mixture containing the amide and the corresponding ammonium salt, then it will not interfere if regeneration of step c) 35 results in a mixture of the amide and the corresponding acid. Namely, it is sufficient that ammonia 117598 7 is added to this mixture before being recycled to step a), or preferably an excess of ammonia is charged in step a) to form this ammonium salt in situ. Reference is made to JACS (J. of American Chemical Society) May 1931, pages 1879-1883. Heat to at least 5 ° C to 160 ° C and preferably to 170 ° C to 230 ° C. Heating is carried out mainly by distilling water. If the reconstituted mixture for carrying out step a) is a mixture containing the amide and the corresponding ammonium salt, the operation of step c) thus comprises converting the amide / ammonium salt mixture from which the amide is reduced and the ammonium salt increased during step a) 10 children to amide. Even if step c) is performed only on a part of the solution, i. that after step b) only a portion of the solution which is high in ammonium salt and low in amide is treated in step c) and then mixed again with the untreated portion. As above, some of the ammonium salt may be in the form of an acid and then ammonia is added to re-obtain the ammonium salt. 1

Step d) is then performed. It is noted that by returning this solution to the cycle in step a) azine can be prepared. If this treatment of step c) is not carried out before step d), the production of azines is lower than that of the previous synthesis, and after 2 or 3 cycles, the production is very poor.

According to the preferred form of the invention, certain impurities may be removed at the high boiling point of the solution obtained at the end of step c). Removal of these impurities at high boiling point can be accomplished quite simply by distillation. This amount of impurities represents 0.1 to 5% by weight of the total solution.

.. 25 This amount is small and may be due to the synthesis conditions of azines, impurities, * ... already present in ammonia, hydrogen peroxide and carbonyl-containing reactant, and it is known that under these conditions, hydrogen peroxide can cause heavy impurities.

• · · ··· .. · *: * Instead of distillation, these impurities can also be removed by sifting off absorbent materials which are microporous particles. For example, ·: · *: the products described in U.S. Patent No. 4,657,751 may be used before the solution containing the amide and possibly the corresponding ammonium salt is recycled. If necessary, supplement the phosphate or any other additive that was present with the acid and the ammonium salt during step a).

:. · .. -jjf 117598 8

It will be appreciated that step c) comprises regeneration of a portion of the amide converted to the corresponding ammonium salt. If an amide and the corresponding ammonium salt have been introduced during step (a), only the fraction of the ammonium salt is regenerated so as to recover the starting mixture of the amide and the ammonium salt.

Example 1 250 ml of a reactor equipped with a stirrer, a condenser and a immersion tube connected to an ammonia tank are charged with the following reactants: - water: 29 grams - acetamide: 59 grams (1 mol) 10 - ammonium acetate: 64 grams (0, 83 moles) - Sodium salt of ethylene diamine tetraacetic acid: 0.1 grams (H 2 O 2 stabilizer) - Methyl ethyl ketone: 72 grams (1 mole).

. ^

The gaseous ammonia is introduced through the submerged tube to saturation and the temperature is raised to 50 ° C.

A stream of ammonia is maintained and then 24.3 g of aqueous solution containing 70% by weight of hydrogen peroxide (0.5 mol) are introduced over a period of 30 min.

After 8 hours 30 min, the reactor is cooled and two phases are separated; ; (organic and aqueous phase) by decantation. Both are analyzed for hydrogen per-

I »I

· * 20 oxide (iodometric) and azine (chromatography on vapor phase).

«** ··: * · *; The aqueous phase contains 0.016 moles of hydrogen peroxide and 0.018 moles of azine of methyl ethyl ketone.

• · • '* The organic phase contains 0.005 moles of hydrogen peroxide.

· Hydrogen peroxide conversion 95.8%.

: *. it 25 Selectivity: 86%, ···, Yield: 82.4% • · * * ·

Example 2 t i; l

Work as in Example 1 but adding 0.5 g of disodium phosphate in the beginning.

117598 9 h after 30 min reaction, the aqueous phase contains 0.023 moles of hydrogen peroxide and 0.014 moles of azine. The organic phase contains 0.003 moles of hydrogen peroxide and 0.391 moles of azine.

Hydrogen peroxide conversion: 96.8% 5 Selectivity: 83.7%

Yield: 81%.

Example 3

Synthesis of azine with a mixture of methyl ethyl ketone and acetamide and disodium phosphate, at the end of step a), the azine of MEK is insoluble and is separated; Decant by decantation and leave the aqueous phase.

The aqueous phase leaving the reactors is washed with methyl ethyl ketone from hydrolysis to extract the azine present in the phase. A new water phase is obtained. It corresponds to the following average composition (w / w): H2O2 = 0.2% 15 ΝΊΙ3 = 5.2% MEK * - 3.5%: * ·· Acetamide - 19.7%: Ammonium acetate = 32.5% H2O = 38 , 8% * · ** g 20 Acin = 0.1%

> I

Impurities = Rest * MEK = Methyl Ethyl Ketone • *

In step c) half of this aqueous phase is treated.

* Used equipment «25 The used laboratory equipment comprises: an adiabatic Oldershaw laboratory column with perforated plates having an inner diameter = 20 mm and containing 20 plates * * · * * * · * · [ . titanium digester with a capacity of 250 cm ^ * *. radiator 30. return container. dosing pumps with plunger, which allow the mixture to be introduced, drained from the digester and the return flow. f. the return is determined by a flow meter with a precalibrated float '117598 ίο. the digester is heated by means of a metal bath maintained at 200 ° C by means of a temperature control. the drain lines as well as the drain pump head are kept at 80 ° C thanks to a double jacket that circulates hot oil to avoid any hardening.

5 Working conditions ''%

The mixture to be treated is introduced into the digester at a flow rate of 349.5 g / h. During normal operation of the appliance the temperatures are as follows: cooker: 180-181 'C

. plate 10: 135 ° C

Top 10: 94-95 ° C

The recovery rate is 0.1.

The dwell time is 1 h 30 min. From the upper end, 190.5 g / h of distillate is recovered having the following composition: NH3: 14.7%: 15 MEK: 6.6% 1120: 78.5% azine: 0.1%; Acetate: 0 • «* / A 159 g / h solution is obtained from the digester with the following composition: 20 Acetic acid: 21.5% * t **; * Acetate: 2.6%“ j '· * Acetamine: 73.6 % J * »II20: 2.2% V: MEK: Low Amount 25 Atsin: Low Amount.

·· · · * · · ... This amount drained from the digester is re-mixed with one half of the unprocessed • · · * P · t and then transported again to step a).

«· ♦ ··

The ammonia recovered from the upper end is partially separated from the water and then returned to the cycle in the same manner as in step a).

* · · • * ♦ * · • e · * · '... · »·

Claims (4)

1. A process for the synthesis of azines starting from hydrogen peroxide, ammonia and a reactant containing a carbonyl group, characterized in that: contains an amide of a weak acid; b) the azine obtained is separated; c) the mixture is treated by heating at a temperature range of 170 ° C to 230 ° C to regenerate it at the beginning of step a) the original amount of amide, and • it is fed at the end of step c) pouring the mixture into the cycle of step a). • * • tel Process according to claim 1, characterized in that the reacting substance in the carbonyl group * t '. ** is a ketone and advantageously acetone, a methyl ethyl ketone or a methyl isobutyl ketone. •• * vt. • · 30 Process according to Claim 1 or 2, characterized in that the amide is selected from a group consisting of acetamide, propionamide, n-butyramide or isobutyramide. i: 117598 Process according to any of claims 1-3, characterized in that in step a) in addition to the amide, the ammonium salt corresponding to the acid from which the amide is derived is used. • · f • · · ···, '-v • · • · • 1 2 3 «• 1 1 * · · · • · 1 * · • · *« · • · 1 • · ·. • · * 1 * · • · • ·· • · · · · · · · · · 1 • 1 • · · • 1 1 • «• · • · · 2 • 1 · * · · 3« • · · * ♦ • · »• · • ·