Recovery of reaction products of hydrazine and carbonyl compounds
United States Patent [191 Brandl et a1.  
 [451 Apr. 1, 1975 [73] Assignee: Bayer Aktiengesellschaft,  
 Leverkusen, Germany 22 Filed: Nov.11, 1971 211 App]. No.: 197,929  
 [30] Foreign Application Priority Data Nov. 17, 1970 Germany 2056357 152] U.S. Cl. 260/566 B [51] Int. Cl. C07c 119/00 [58] Field of Search 260/566 B [56] References Cited UNITED STATES PATENTS 3,382,041 5/1968 Needham et al. 260/566 B 3,382,281 5/1968 Jankowski et a1. 260/566 B FOREIGN PATENTS OR APPLICATIONS 1,122,034 6/1972 Great Britain 260/566 B OTHER PUBLICATIONS Vogel Practical Organic Chem. Longmans, Green (1949) page 44.  
 Treyba] Liquid Extraction&#34; McGraw-Hill (1963) pages 23-25.  
 Miall A New Dictionary of Chemistry, Interscience (1962) p. 481.  
 The Van Nostrand Chemists Dictionary (1953) page 620.  
 Primary Examiner-Donald G. Daus Assistant Examiner,D. B. Springer Attorney, Agent, or FirmBurgess, Dinklage &amp; Sprung [57] 0 ABSTRACT In the preparation of reaction products of hydrazine and carbonyl compounds, such as azines, by reacting ammonia with chlorine or compounds containing active chlorine, e.g. bleaching lye or chloramine, in aqueous phase and in the presence of a carbonyl compound, in accordance with the invention the hydrazine reaction product is recovered by having present a hydrophilic substance such as sodium or calcium chloride in amount sufficient to cause separation of the product into two phases, the lower of which is aqueous and the upper of which is organic and contains the hydrazine reaction product. If the hydrophilic substance is non-acidic so it will not interfere with the reaction, it can even be present from the outset.  
 4 Claims, No Drawings RECOVERY OF REACTION PRODUCTS 01F HYDRAZINE AND &#39;CARBONYL COMPOUNDS This invention relates to a process for the preparation of reaction products of hydrazine with carbonyl compounds by the reaction of active chlorine with ammonia in an aqueous phase in the presence of a carbonyl compound. These reaction products may be worked up to hydrazine in known manner.  
  Hydrazine, which as is well known is obtained by the reaction of chlorine with ammonia via chloramine as the intermediate stage is obtained in most processes in the form of dilute aqueous solutions from which the pure hydrazine can be isolated only with considerable expenditure of energy. Thus, for example, it is known to distill the hydrazine from the reaction mixture. l-Iydrazine forms a constant boiling mixture with water in a molar ratio of about 1 :1, which is known as hydrazine hydrate. The boiling point of this azeotropic mixture is above 100C. Salt-containing solutions which are obtained, e.g. in the Raschig synthesis of hydrazine, must therefore be evaporated to dryness in order to obtain hydrazine hydrate.  
  It has therefore been proposed to react hydrazine with a water-soluble low-molecular weight carbonyl compound, especially acetone, to convert it into a reaction product of hydrazine and the corresponding carbonyl compound, e.g. into the corresponding azine. These compounds form azeotropic mixtures with water which boil at a temperature below 100C. They can therefore be distilled from dilute aqueous solutions which still contain salts and other dissolved substances. Even this process involves considerable expenditure of energy.  
  In German Pat. No. 1,082,889 there has been disclosed a process for the preparation of hydrazine by the reaction of gaseous chlorine with excess gasous ammonia in the presence of a ketone or an aldehyde, which process consists in reacting the mixture of excess ammonia and the particular ketone or aldehyde with chlorine in the gaseous phase, ammonium chloride, ammonia and the excess ketone or excess aldehyde being removed from the reaction mixture, and the resulting re action product being worked up to hydrazine. This process, which is operated exclusively in the gaseous phase, is also relatively difficult to handle.  
  It has also been proposed to obtain hydrazine with the aid of aldehydes or ketones which are immiscible with water by extracting the hydrazine from the aqueous phase in the form of the corresponding azine. Examples of aldehydes which have been mentioned for this purpose are benzaldehyde and propionaldehyde (see L. F. Audrieth and B. A. Ogg, The Chemistry of Hydrazine, page 45, 1951, John Wiley &amp; Sons, Inc., New York). For economical reasons, however, the use of such solvents would hardly be considered for a commercial process. Q  
  It is accordingly an object of the present invention to provide a simple, inexpensive process for recovering a reaction product of hydrazine and a carbonyl compound.  
 In accordance with the present invention, it has surdition of a hydrophilic substance such as a salt into a liquid, a two-phase system forming in which the hydrazine is concentrated in the less aqueous phase. The degree of distribution of hydrazine or of the reaction product of hydrazine with the carbonyl compound between the less aqueous phase and the more highly aqueous phase depends on the degree to which the carbonyl compound used is miscible with water and on the concentration of the hydrophilic substance. If the concentration of the hydrophilic substances is low, as is the case when synthesis is carried out in the conventional manner, and if the carbonyl compound used is completely or partly miscible with water, theneither no diphasic reaction solutions are obtained at all or the reaction products are distributed in both phases.  
  In the presence of a carbonyl compound which is completely or partly miscible with water and of a suitably high salt concentration, a diphasic system is formed in which hydrazine or the reaction products of hydrazine with the carbonyl compound are highly concentrated in the less aqueous phase. The less aqueous phase has almost the same composition as an azine. Salts and ammonia remain in the highly aqueous phase.  
  The most suitable starting materials for preparing the initial reaction product of hydrazine and carbonyl compound according to the invention are bleaching lye and ammonia which are used as components for the Raschig process, but intermediate products already formed from the reaction between active chlorine and ammonia, e.g. chloramine, may also be used for the process according to the invention, and aqueous solutions already containing hydrazine are also suitable.  
  Bleaching lye containing from about 50 to 175 g of active chlorine per liter may be reacted directly with the ammonia component which is added either as an aqueous ammonia solution having a concentration of from about 5 to 30% by weight of NH or directly in the form of NH gas. The proportion of ammonia to chlorine should be approximately in the region of 6 to 20 moles of ammonia per mole of active chlorine. The reaction is advantageously carried out at a temperature in the range of from about 0C to C, preferably about 30C to 60C, at normal or elevated pressure.  
  The reaction is generally carried out in the presence of the carbonyl compound but if desired a carbonyl component may be added to an aqueous hydrazine solution already formed. The carbonyl compound is then advantageously added in such an amount that the reaction results in at least a proportion of carbonyl compound to hydrazine required for the formation of azine, i.e., carbonyl compound: hydrazine 2.  
  Hydrophilic substances which are not acid in reaction may in addition he added to the reaction system. These additives, which may be added in any amounts up to the saturation concentration, that is to say up to the formation of a ground sediment, enable the hydrazine component to be highly concentrated in the nonaqueous phase even if the carbonyl compounds used are normally completely or at least to a considerable extent miscible with water.  
  After completion of the reaction, the two phases are brought into intimate contact with each other by shaking, stirring or other suitable methods, using conventional apparatus for this purpose.  
  When the two phases are completely separated, the hydrazine component or the ketazine or aldazine is found almost quantitatively in the relatively nonaqueous phase. Separation of the non-aqueous from the aqueous phase may be carried out in a separation funnel. Conventional apparatus for phase separation, e.g. extraction columns, may be used for carrying out the process of the invention on a commercial scale. Mixing and phase separation may also be carried out in an apparatus of the mixer-settler type or in a countercurrent extraction column.  
  The carbonyl compounds used are substances of the following general formula wherein R represents hydrogen, alkyl or aryl,  
 R represents alkyl or aryl or R and R together represent a cycloaliphatic radical.  
 The radicals R and R may also be substituted.  
  It is preferred to use carbonyl compounds such as acetone, methylethyl ketone, methyl isobutyl ketone, cyclohexanone, cyclopentanone, propionaldehyde.  
  Even if the carbonyl compounds used are partly or completely miscible with water, the process according to the invention enables separation into the two phases to be achieved economically by the presence of hydrophilic substances in the aqueous phase or in the reaction mixture.  
  Any substances which are not acids in reaction and which are water-soluble to a certain extent are suitable for use as hydrophilic substances. Electrolytes such as NaCl, KCl or CaCl are particularly suitable as well as substances which are alkaline in reaction such as NaOH or NH With increasing excess of the carbonyl compound at the stage of phase separation, higher yields of azine separating in the organic phase are obtained.  
  The process according to the invention may be carried out either continuously or intermittently. In the continuous process, it is found to be particularly advantageous to recycle the aqueous ammoniacal salt solution, which is almost free from azine, after the water and the salt formed in the reaction has been extracted.  
  The products obtained according to the invention from dilute hydrazine solutions or in the case of hydrazine synthesis in a separate non-aqueous phase may be directly converted into hydrazine or hydrazine derivatives in known manner, generally without any further working up operations. The carbonyl compound liberated is advantageously used for recovering additional products according to the invention.  
  The process according to the invention will now be described more fully with the aid of the following examples.  
 EXAMPLE 1 a 200 ml portions of an aqueous solution containing 5.0 grams (0.1 mole) of hydrazine hydrate and varying quantities of NaCl were vigorously mixed with 0.22 mole of a. 16 g of methylethyl ketone; or  
  b. 13 g of propionaldehyde at room temperature. The percentage of hydrazine found in the non-aqueous phase after phase separation, based on the amount of hydrazine in the starting solution, is shown below for different amounts of NaCl in the starting solution:  
 13 g of NaCl a) 61.6% b) 48.7% 50 g of NaCl 21) 92.1% b) 90.1%  
 EXAMPLE 1 b 200 ml portions of aqueous solution saturated with NaCl and containing NaCl ground sediment and having EXAMPLE 2 a When different substances were present in solution, vigorous mixing of 200 ml of aqueous solution of 5.0 g (0.1 mole) of hydrazine hydrate with 16.0 g 0.22 mole of methylethyl ketone resulted in the following hydrazine contents (based on the starting solution) in the non-aqueous phase: without additives no phase separation 26.2 g NH, 28.2% 26.2 g NH3 +13 g NaCl 61.5% 50 g CaCl- 76.1% 50 g NaOH 85.2%  
  The process according to the invention may also be applied to hydrazine solutions which are obtained by the urea synthesis process, i.e., by the reaction of urea with bleaching lye followed by the addition of NaOH. These solutions contain Na CO in addition to hydrazine and NaCl and their use is illustrated in the following examples.  
 EXAMPLE 2 b Approximately 2,500 ml of a urea synthesis solution containing 107.9 g of hydrazine hydrate were mixed with 660 ml of acetone at 40C. The resulting mixture separated into two phases when left to stand. The aqueous phase was again treated with ml of acetone. The following results were obtained on analysis:  
 Hydrazine Acetone Molar hydrate ratio Upper, non-aqueous phases 82.3 g 444.6 g 4 6 aqueous phase (containing 26.4 g 161.0 g 5 3 NaCl and Na CO 76% of the hydrazine was transferred to non-aqueous acetone phase by a separation carried out in two stages. 1  
 EXAMPLE 3 1,200 ml of aqueous ammonia solution containing approximately 14 moles of NH and (a) 0; (b) 200 and (c) 375 g of NaCl were reacted with from to ppm of glue and 400 ml of aqueous bleaching lye containing 155 g per liter (0.87 mole) of active chlorine and 140 g 1.95 mole) of methylethyl ketone (molar ratio of ke- NaOH solution. The reaction mixture obtained separated into two phases. The following results were obtained from analysis: 1  
 tone: active chlorine 2.2: l) at C to C with vig- 5 H H MEK orous stirring. The reaction mixture was then heated to y y MR 45C and stirred for a further one-half hour. The reacupper phase 21.3 g 64.4 g 2.1 tion mixture separated into two phases. The hydrazinelower Phuse g 207 ketone compounds, calculated as hydrazine hydrate g: (HyHy) were distributed in the two phases as follows: 10  
 EXAMPLE 6 a) b) c) 237 g of chloride of lime containing 27.7% of active l5 chlorine were introduced incrementally with vigorous 25 stirring at 20C in the course of 1 hour into a solution of NaCl 0 200 g 375 prepared from 1,200 ml of 25% NH in water, 150 g of 9P1 P 287 g 364 g &#39;s HyHy CaCl 200 g of methylethyl ketone and 0.1 g of nitriloy&#39;eld triacetic acid. The reaction mixture was then stirred for Lower phase 10.0 g 4.0 g 2.1 g of H 20 a further 20 minutes and left to separate into two phases. The following results were obtained from analysis:  
  According to the analytically determined composition of 31.2% of hydrazme hydrate and 98.0% of meth- HyHy MEK MR ylethyl ketone, corresponding to a molar ratio of 1:2.2, 25 the upper, non-aqueous phase consists of about 90% of upper phase 21.7 g 81.0 g 2.6 the azine of methylethyl ketone and about 10% of ex- 1 Phase %:737 g cess ketone. The ammonia content is less than 0.5% Om g we and the sodium chloride content less than 0.1%.  
  EXAMPLE 4 EXAMPLE 8 9 g of NaCl were added to the aqueous ammonia A chloramine solution prepared from 300 ml of 10% solut1on of Ex. 3 and lnstead of the molar ratlo (MR) NH3 in water and 320 ml of bleaching lye (100 g per of ketone: act1ve chlor1ne 2.2:1 used in example 1 a, liter of active chlorine) at was introduced with molar ratios varying from 1.6:1 to 3.011 were used. The 35 Stirring into an aqueous mixture kept at which followmg y1elds 0f hydrazme hydrate were obtained: had been prepared from 1,000 m 0f25% OfNH3 in ter, 150 ml of methyl ethyl ketone, 380 g of NaCl and Upper phase Lower phase 0.1 g of rutrilotriacetlc acid. About 100 l1ters of NH 25.7 g HyHy 7.2 g HyHy gas were lntroduced 1n the course of the 1 hour s experr 40 iment to replace ammonia losses. The resulting reac- MR 79.8 g MEK Wm 60 MEK tion mixture separated into two phases. The following MR 23 MR 15 results were obtained from analys1s: 34.7 g HyHy 4.4 g HyHy atMR=2.0 8W Id 102.0 g MEK I ylc 16.2 g MEK HyHy MEK MR MR MR u er hase 16.5 94.0 3.9 7 36.8 1.1 y y g y ld vser ghase 2.2 2 40.8 5 12.8 at MR 85% yield Total 18.7 g 83% yield.  
  123.0 g MEK 20.1 g MEK MR 2.3 MR 4.4 at MR 381 g y y 87l7 d g y It w111 be apprec1ated that the 1nstant speclflcation 1420 g MEK 329 g MEK and examples are set forth by way of illustration and MR 26 MR not 11m1tat1on, and that varlous mod1f1cat1ons and changes may be made without departing from the spirit and scope of the present invention. As in example (3) so also in this example 4 the upper What is claimed is: phase consists mainly of the azine of methylethyl ke- 1. In the preparation of reaction products of hydratone (MEK) in addition to some free ketone, and the zine and acetone by reacting chlorine or compounds NaCl content is less than 0.1% throughout. which contain active chlorine with ammonia in the aqueous phase and w1th a acetone, and thereafter re- EXAMPLE 5 covering the hydrazine reaction product, the lmprove- 6.5 liters of C1 per hour diluted with 30 liters of N ment which comprises rendering the reaction medium er hour were reacted at 30C, with vigorous stirring, substantiall insoluble for the resultin h drazine- P y g y with an aqueous solution obtained from 1,200 ml of a acetone compound by effecting the reaction in the 25% solution of NH in water, 200 g of NaCl and 20 ml presence of at least one salt selected from the group of a 0.1% solution of glue and with ml of methylethyl ketone. The pH was kept constant at about 13.0  
 consisting of NaCl, CaCl and KC] present in such amount that the system separates into an aqueous saltcontaining phase and a substantially non-aqueous phase, separating the non-aqueous phase formed con- 3. Process according to claim 1, wherein the salt used taining the reaction product of hydrazine and acetone i 1 from the Substantially aqueous phase and recycling 4. Process according to claim 1, wherein the aqueous said aqueous phase for use in the reaction of further h h d b l quantities of chlorine with ammonia and acetone. p ase m w 1c Sal mac procee S ls Su Stanna 1y 2. Process according to claim 1, wherein the salt used Saturated with Said Salt iS NaCl.