Patented Aug. 17, 1954 2,686,811 UNITED STATES PATENT OFFICE 2,686,811 ONESTEP PROCESS FOR PREPARNG DISOPROPYLAMINE Willard C. Bull, Joplin, Mo., assignor to Commer cial Solvents Corporation, Terre Haute, Ind., a

corporation of Maryland NoDrawing. Application October 12, 1949, Serial No. 121,072. 6 Claims. (CI. 260-585) 1. 2 My invention relates to a process for prepar expensive starting materials or a two step process ing diisopropylamine by catalytically reacting Wherein the ammonia, ketone and hydrogen are annonia, acetone and hydrogen. More par first reacted in the presence of a nickel catalyst ticularly, my invention relates to a one step proc to produce a primary amine which is Subsequent eSS for preparing diisopropylamine by reacting ly reacted in a separate operation with addition ammonia. With acetone and hydrogen in the pres alketone and the reaction product thus produced ence of water and a modified copper oxide cata catalytically hydrogenated to form the desired lyst. Secondary amine. By my new process, diiso In the past the customary method of produc propylamine is simply produced in a single op ing Secondary amines, and in particular dialkyl IO eration by the reaction of ammonia, acetone and amines such as diisopropylamine, has been to em hydrogen in the presence of water, thus eliminat ploy a process such as that of Loffler (Berichte, ing a complete Step and resulting in a tremendous volune 43, pages. 2031-5), Skita, and Keil Saving of time, equipment and materials. (Berichte, vol. 61B, pages 52-9), or Adkins et al. My proceSS consistS eSSentially of charging ann (U.S. Patent No. 2,045,574). Lofler prepared his 5 monia, acetone, water and a catalyst into a suit Secondary annines by mixing acetone with a cold able reaction vessel and hydrogenating the mix Saturated absolute alcoholic Solution of ammonia, ture at elevated temperatures and pressures until and after 1 Week gradually adding sodium to the hydrogen ceases to be absorbed. The reaction resulting product. From the use of 80 grams of mixture is then cooled, the contents discharged acetone, however, he obtained only 12 grams of and the products isolated in a known manner. a mixture of isopropylamine and - diisopropyl In carrying out my improved process for the amine. Skita, and Keil prepared diisopropyl production of diisopropylamine, can use pure amine by mixing 16 grams of acetone with 20 mi. acetone or commercial grades of acetone, which of 24% aqueous ammonia and hydrogenating the are nearly pure. Acetone in aqueous Solution can resulting product at room temperature and 3 at 25 be used, provided it does not contain. Water in ex mospheres pressure in the presence of a colloidal ceSS of the amounts shown below, to give optimum platinum catalyst. A yield of only 19% of di yields of diisopropylainine, isopropylamine was thereby obtained. Adkins The ammonia is preferably used in the form of et al. produced secondary and tertiary amines by anhydrous liquid annonia, although aqueous-am hydrogenating a mixture of a primary amine and monia, can be used, provided it does not contain r a carbonyl compound in the presence of a nickel Water in excess of the announts shown below, to catalyst and claimed to have obtained a 70% give optimum yields of diisopropylamine. yield of bicyclohexylamine by thus reacting cyclo The ratio of the reactants, namely acetone and hexanone and cyclohexylamine (based on the ammonia, can be varied over a fairly wide range. cyclohexylamine used). : , ..., ...'. Changes in the ratio of reactants, however, af It will be obvious that the Lofler process is im fect to a considerable degree the character of practical for large Scale commercial utilization the products obtained as a result of the reaction. both because of the time required for the reac For example, for optinum yields of diisopropyl tion and the low yields of the desired product. amine prefer to use 2 moles of acetone to 1 mole The process of Skita, and Keil is similarly un of annonia. Changing the ratio to 1 innole of Suitable because of the low yields of secondary 40 acetone to 1. nole of aminonia results in greatly amines produced. The Adkins' et al. process has increased amounts of unreacted ammonia of the the added disadvantage of starting with a pri Order of 90% of the ammonia, charged... if, on mary amine thus requiring two operations in the other hand, the ratio is raised to 8 moies of stead of one as in applicant's process to be de acetone to 1 of ammonia, a large amount of the scribed below. When this fact is taken into con 45 acetone used is wasted. sideration their yield of 70% of Secondary The amount of water which I use in my process amine becomes very much lower when recal in order to obtain optimum yields of diisopropyl culated on the basis of the annonia, and ketone amine ranges from 3 to 10%, based on the total .. used as the initial starting materials. volume of the reactants. When amounts below Applicant's new process and the yields ob 50 this range are employed the yields of diisopropyl tained by it show even more striking advantages amine are reduced and increased amounts of an over the other processes previously ilable- - - - for monia remain unreacted. When amounts of wa the production of diisopropylamine since the ter in excess of the above range are employed, prior art processes in general require the use of 65 the yields of diisopropylamine are decreased and

2,686,811 3. 4 . the presence of the increased amount of water liquid reaction mixture through a column in Cori results in an increased amount of unreacted an tact with hydrogen gas under proper conditions monia, in the reaction product and reduced of temperature and pressure. Still another pro amounts of monoisopropylamine. cedure consists of passing the reaction mixture The catalyst used in my process is a modified 5 through a stationary bed of pelleted or supported copper oxide catalyst Such as copper chronite or metal chromite catalyst enclosed in a reaction co-precipitated cupric oxide-calcium fluoride. vesse of Suitable design. The copper chronite catalyst can be produced The following examples are given to illustrate by the method of Callingaert and Edgar described my invention, and are not to be construed as lim in Ind. Eng. Chen. 26, 878-880 (1934). This O iting it to the exact reactants or conditions method consists generally, of reacting a copper described: salt, such as the Sulfate, with the dichromate of EXAMPLE an alkali metal Such as Sodium, and annonia, A series of experiments on the production of to form a precipitate of copper ammonium chro diisopropylamine from ammonia, acetone, and nate, which is then Washed, dried, and roasted 5 hydrogen in the presence of water With a copper to produce copper chronite Suitable for use in chronite catalyst was carried out according to my process. Co-precipitated copper oxide-cal the following procedure, to demonstrate the ef cium fluoride can be produced by the method of fect of temperature on the reaction: Stenge and Maple described in U. S. Patent A mixture of acetOne and ammonia in a 2:1 2,381,316 which coinprises reacting copper Sulfate, 20 ratio of acetone to anmonia, 3% by weight of Sodium fluoride, calcium chloride, and Sodium. Copper chronite catalyst, and 5.5% by Volune of hydroxide to form a precipitate consisting Of water, based on the total amount of acetone and cupric hydroxide and calcium fluoride which is annonia, was introduced into a stainless Steel then Separated, Washed and dried to produce the bomb having a total volume of 1840 m. After co-precipitate cupric OXide-Calcium fluoride cat sealing the bomb, hydrogen was introduced to a alyst. Other methods may be used for produc pressure of 1000 lbs. per Sq. in... gauge and the ing the catalysts, the above procedures being bomb heated to the desired temperature. As the cited merely as convenient and desirable meth hydrogenation proceeded, additional hydrogen Ods, and other modified copper oxides can be was introduced fron time to time to restore the used as catalysis in my process. 30 pressure to its initial level. After hydrogen ad The temperatures employed in my process are sorption had stopped the bomb was cooled, preferably of the order of 150° C. to 180° C., but vented, and the reaction product discharged and may extend over a range of about 140 to about recovered by fractional distillation through an 200° C., the optirnunn reaction temperature being efficient laboratory column. The results obtained apparently about 160° C. In general, when reac 35 tion temperatures near the limits of the range are shown in Table I. Specified are used, the yields of diisopropylamine Toole I are comparatively low, and consequently the product contains unreacted ammonia. Conversion percent based In carrying out ray process Superatmospheric on annonia in reaction 40 mixture preSSures of from 500 to 1500 pounds per Sq. in. Temperature, C. are used. The lower pressures require a longer Tiisopro- Monoisopro reaction time and are characterized by lower pylanine pylamine yields. As the pressure increases the reaction time is decieased and While there is apparently 45 135. 4.3 3.4 no upper linit to the pressure which can be used, 52.0 18.3 67.0 3.2 I prefer to carry out my process at pressures 80. 65.5 1.0 SoineWhat less than 1500 lbs. per Sq. in., and more Specifically at approximately 1000 lbs. per Sq. in. The reaction is gauged by the pressure drop 50 EXAMPLE in the reaction chamber. During the reaction, hydrogen is added. Whenever the pressure in the A Series of experiments was conducted at a reaction vessel drops below the selected operat constant temperature of 160° C. following the ing pressure. The reaction is complete when no procedure outlined in Example I, and designed further pressure drop occurs thus indicating that 55 to show the effect of variations in pressure. The hydrogen is no longer being absorbed. results obtained are shown in able II. in Carrying out lay process a mixture of the reactants and catalyst is introduced into a pres Table II Sure WeSSel equipped With a Suitable stirrer and a jacket or coil for inaintaining the charge at the Conversion percent based 60 On annonia in reaction. desired tenperature. Preferably, the vessel is mixture cooled prior to introduction of the reaction mix Pressure in lbs. per sq. in. ture in order to minimize the loss of ammonia. Diisopro- Monoisopro ihe Irea Cition. Vessel is the sealed and heated to pylamine pylamine the desired reaction temperature. During the 65 reaction, hydrogen is added either intermittently 500---- 8.5 .. 5 1,000- 65.4 3.8 Or continuously as required in order to maintain the preSSure at the desired level. When the re 1,500.-- 60.0 5.0 action is complete as evidenced by cessation of EXAMPLE I pressure drop, the reaction mixture is cooled, the 70 reaction Wessel vented, the contents discharged, A series of experiments was conducted at a and the product isolated in any convenient man constant temperature of 160° C. and at a constant nei. Such as by fractional distillation. preSSure of 1000 lbs. per Sq. in. following the pro Alternately, my process is carried out by pass cedure described in Example I and designed to ing a slurry of the powdered catalyst and the 75 show the effect of variations in the amount of 2,686,811 5 6 Water used. The results obtained are shown in and in the presence of water and a catalyst se Table III. lected from the group consisting of copper Table III chromite and co-precipitated copper oxide-cal cium fluoride, a mixture of ammonia, hydrogen, Conversion percent based 5 and acetOne. on ammonia in reaction mixture 2. A proceSS for the manufacture of disso Water, percent by vol. propylamine which comprises reacting under Diisopro- Monoisopro Superatmospheric pressures and at elevated tem pylamine pylamine peratures and in the presence of water and copper 10 chromite catalyst, a mixture of ammonia, hydro 39.3 11.9 gen, and acetOne. 53.2 30.5 67.0 13.2 3. A proceSS for the manufacture of diiso. 41.7 19.9 propylamine which comprises reacting under 105------56. 0 Superatmospheric pressures and at elevated tem 5 peratures and in the presence of Water an co EXAMPLE IV precipitated Copper Oxide-calcium fluoride cata lyst, a mixture of ammonia, hydrogen, and A mixture consisting of acetone and annonia, acetOne. in a 2:1 ratio of acetone to ammonia, 3% by 4. A process for the manufacture of diiso weight of copper chromite catalyst and 5.5% by 20 propylamine which comprises reacting under volume of water based on the total amount of Superatmospheric pressures ranging from 500 to acetone and ammonia used, was hydrogenated at 1500 lbs. per sq. in. and at a temperature between 1000 lbs. per sq. in. at 160° C. until no further about 140-200 C., in the presence of water and preSSure drop occurred thus indicating comple copper chromite catalyst, a mixture of ammonia, tion of the reaction. The product was distilled 25 hydrogen, and acetone. and the following materials recovered: 64.8% 5. A process for the manufacture of diiso diisopropylamine based on the amount of am proplyamine which comprises reacting ammonia, monia charged, 13.2% isopropylamine based on hydrogen and acetone at a pressure between about the amount of ammonia, charged, 9.2% of the 900-1100 lbs. per Sq. in, at a temperature between ammonia, and 5% of the acetone charged. 30 about 140-180° C. in the presence of water and EXAMPLE W. copper chronite catalyst. 6. A process for the manufacture of diiso A mixture consisting of acetone and ammonia in propylamine which comprises reacting ammonia, a 2:1 ratio of acetone to ammonia, 3% by weight and acetone in approximately a 2:1 ratio of co-precipitated cupric oxide-calcium fluoride cat 35 acetone to ammonia, with hydrogen at a pressure alyst and 5.5% by volume of water based on the between about 900-100 lbs. per Sq. in. and at a total amount of acetone and ammonia used, was temperature between about 40-180° C. in the hydrogenated at 1500 lbs. per Sq. in at 160° C. presence of from 3-10 volume per cent of water, until no further pressure drop occurred thus based on the total amount of ammonia, and a ce indicating completion of the reaction. The prod 40 uct was distilled and the following products re-.. tone, and copper chromite catalyst. covered: 63%. diisopropylamine based on the amount of ammonia, charged and 12% isopropyl References Cited in the file of this patent amine based on the amount of ammonia, charged. UNITED STATES PATENTS It is to be understood that I am not limited to 45 Number Name Date the preferred procedure as herein set out and 2,121,033 Hasselstrom ------June 21, 1938 that any equivalents or changes which would 2,278,372 Olin et al.------Mar, 31, 1942 Occur to one skilled in the art are to be construed 2,278,373 Olin ------Mar. 31, 1942 as lying within the scope of my disclosure and 2,422,743 O'Loughlin ------June 24, 1947 claims hereunto appended. 50 2,452,602 Robinson et al.------Nov. 2, 1948 What I claim is: 2,497,310 Larson ------Feb. 14, 1950 1. A process for the manufacture of diisopropyl amine Which comprises reacting under Superat OTHER REFERENCES mospheric pressures and at elevated temperatures Yamaguchi, Chem. Zent, 1926, I, p. 3538.