UNITED STATES PATENT OFFICE 2,686,811 ONESTEP PROCESS for PREPARNG DISOPROPYLAMINE Willard C

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.

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