Patented Jan. 25, 1938

umreo srirss 2,106,697 PRooEss FOR THE. MANUFACTURE or ‘Y y ' ACETAMIIDE Wendell P. Munro, Bound Brook, Elmore H. Northey and Hans Z. Lecher, Plain?eld, N. J., assignors to The C'alco Chemical Company, Inc., Bound Brook,- N. J., a corporation of Dela Ware No Drawing. Application April 13, 1936, Serial No. 74,194 5 Claims. (GI. 260—124) The present invention relates to a method of producing acetamide, and more particularly to a tended to limit the invention to speci?c condi new process of producing acetamide at high tions and proportions given: purity. Example Most of the known processes for producing acetamide present serious operating di?iculties 94 parts of methyl acetate are agitated with if a pure product is desired, and especially where 180 parts of 28% aqueous ammonia solution un the product must be anhydrous. Thus the usual til the methyl acetate is all dissolved. The solu method of distilling ammonium acetate requires tion is then allowed to stand for a total time of a slow and long distillation. It has also been 20 hours at room temperature. Reacting then proposed to bring about reaction between ethyl being complete, the methyl alcohol, water and 1O acetate and ammonia but this process also pro excess ammonia, and traces of unreacted methyl duces an acetamide which is not pure and which acetate are distilled o? through a fractionating notably contains water due to the great hygro column. The residue is ground with 47 parts of 15 scopicity of the acetamide. methyl acetate, the methyl acetate liquor ?ltered According to the present invention, acetamide, off, the crystals washed once with 47 parts 15 is produced by reacting aqueous ammonia on methyl acetate, and twice with 13 parts of ben ethyl or particularly methyl acetate which re zene, and ?nally dried in vacuo at 60-70° C. acts much more rapidly and completely, and the The combined wash liquors are used without fur 20 puri?cation is effected after distilling off the ther treatment to make another batch of acet water and alcohol formed by washing the acet~ amide. The yield of acetamide is good, and the 20 amide with anhydrous methyl acetate or in the product is obtained as colorless, practically odor case where ethyl acetate is used as a raw ma less crystals of high quality. ’ terial, with anhydrous ethyl acetate. Methyl Ethyl acetate may be used in a similar man acetate and similarly ethyl acetate, have not a ner but the reaction is not as rapid or as com high solvent action on acetamide at ordinary plete as with methyl acetate and the methyl temperatures, but tend to dissolve Water and acetate therefore constitutes a preferred em thus dry out the acetamide. The acetamide ob bodiment of the invention, particularly as the tained may be further washed with an inert or solvent power of methyl acetate for water is ganic liquid like benzene which has but little greater than that of ethyl acetate and it is there solvent action on acetamide and which protects fore a more efficient washing medium than ethyl 30 the surface of the puri?ed product from absorp acetate so that improved results are also obtained tion of water. As the reaction of the ester with in the second step of the process. It will be ap ammonia takes place in aqueous medium, the parent that the present invention eliminates cost 35 wet ester resulting from washing the acetamide ly equipment for a troublesome fractional dis may be used instead of pure anhydrous ester tillation or for distillation of the acetamide itself and the washing step results therefore in no ma_ and the reaction is not carried out at high tem terial loss of raw material and acetamide. When peratures or under high pressures which further a small amount of an inert organic liquid like 40 benzene is used for ?nal washing and coating, eliminates the necessity for expensive apparatus. the benzene may remain with the ester to be The expense and loss incident to recrystallization used for the next batch; it will be later dis which may be necessary in processes used hither to, is also avoided without any loss in purity of tilled oif together with water, unreacted am~ the acetamide. monia and ester, and the alcohol formed. In order to obtain a pure product in a good What we claim is: yield, the reaction should be carried out below 1. A process of producing acetamide which 45 80° C., because at higher temperature the forma comprises reacting aqueous ammonia with an tion of ammonium acetate becomes a disturbing acetic acid ester of a lower monohydric para?in factor. The reaction proceeds with su?icient alcohol having good solvent power for water, dis speed and completeness at ordinary temperatures tilling off alcohol formed, unchanged ammonia and neither heating nor cooling are therefore and unreacted ester and water, washing the necessary which reduces the cost of apparatus. product with fresh ester followed by washing The invention will be described in greater de with a small amount of an inert organic liquid tail in connection with the following speci?c‘ having low solvent action upon water and using 55 the washing liquor as raw material for the next example which is illustrative only and is not in batch. 55 2 ' 2,106,697 upon water and using the wash liquor as raw 2. A process according to claim 1 in which the material for the next batch. temperature of reaction is below 80° C. 4. A method according to claim 3 in which the 3. A process of producing acetamide which temperature is below 80° C. comprises reacting aqueous ammonia on methyl 5. A method according to claim 3 in which the 5 acetate, distilling o?E excess'ammonia and un inert organic liquid is benzene. reacted methyl acetate and the methyl alcohol WENDELL P. MUNRO. formed and water, washing the product with ELMORE H. NORTHEY. methyl acetate followed by a small amount of HANS Z. LECHER. an inert organic liquid having low solvent action