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Nited States Patent ICC , ’ Patented June 5, 1956

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Nited States Patent ICC , ’ Patented June 5, 1956 2,749,358 nited States Patent ICC , ’ Patented June 5, 1956 1 2 should be understood, however, that they are illustrative only and are not to be taken as limiting the invention. 2,749,358 Parts are by weight unless otherwise speci?ed. Conver sions are based on the compound being nitrosated. A PREPARATION OF OXIMES catalyst which is insoluble in the active methylene com Edward L. Reilly, Woodbury, N. J., assignor to E. I. du pound being nitrosated may be dissolved in a suitable Pont de Nemours and Company, Wilmington, DeL, a solvent. corporation of Delaware Example 1 No Drawing. Application February 18, 1955, A mixture of 20 parts of methyl ethyl ketone, 50 parts Serial No. 489,270 10 of pyridine and 2 parts of cupric chloride was added to an autoclave at 24° C. and the autoclave was pressurized 8 Claims. (Cl. 260—465) to 195 lb./sq. in. ga. with nitric oxide. The mixture was heated to initiate the reaction, and a maximum tempera ture of 104° C. was attained, at which point the pressure The present invention relates to a novel process for 15 was 225 lb./sq. in. ga. When further nitric oxide ab the preparation of oximes. The invention relates speci? sorption Was no longer apparent, the autoclave was cooled cally to a process for the preparation of oximes by the and vented. The reaction mixture was ?ltered to remove reaction of nitric oxide and a compound having an active undissolved catalyst and treated with an excess of 10% methylene group. sodium hydroxide to form the salt of the oxime produced. Oximes are useful as chemical intermediates, especially 20 The caustic solution was extracted with ether to remove for the preparation of lactams, and have also been pro unreacted methyl ethyl ketone (7.5 parts) and solvent, posed for use as catalysts, photographic sensitizers, in acidi?ed and again extracted with ether. Evaporation of secticides, fungicides and bactericides. Oximes are gen the ether layer produced 5.6 parts of diacetyl monoxime erally prepared either by the condensation of an alde (20% conversion, 32% yield). hyde or ketone with hydroxylamine or by the nitrosation 25 of an activated methylene compound to produce a nitroso Example 2 intermediate which rearranges spontaneously to the A mixture of 20 parts of methyl ethyl ketone, 100 parts oxime. By the term active methylene compound is by volume of dirnethylamine and 2 parts of manganous meant compounds of the general formula X—-CH2-—Y in sul?de was added to an autoclave at 40° C. and the auto which X is a negative, i. e. electron attracting, group and 30 clave was pressurized to 150 lb./sq. in. ga. with nitric Y is either an alkyl or a negative group. The ordinary oxide. The mixture was heated to initiate the reaction negative groups, i. e. acyl, aroyl, carboxyl, carbalkoxyl, and a maximum temperature of 118° C. was attained. nitro, cyano, imino, and aryl groups, vary greatly in their When the pressure decreased, additional nitric oxide was ability to promote reaction at the adjacent methylene introduced to raise the pressure to the initial level. When group. Generally, the ease of reaction of the methylene further nitric oxide absorption was no longer apparent, group increases with the negativity, i. e. electron attract the autoclave was cooled and vented. The reaction mix ing ability, of the adjacent group or groups. ture was treated as described in Example 1 and 8 parts Nitrosation of active methylene compounds has been (30% conversion, 40% yield) of diacetylmonoxime was effected by nitrous acid, an inorganic nitrite and an acid, recovered. an alkyl nitrite and an inorganic acid or base, nitrosyl 40 Example 3 chloride, nitrosylsulfuric acid and nitrogen trioxide. However, none of these nitrosating agents is equally effec A mixture of 20 parts of methyl ethyl ketone, 100 parts tive with all active methylene compounds. Moreover, the of pyridine and 2 parts of chromous chloride was added known processes for the preparation of oximes involve to an autoclave and the autoclave was pressurized to 405 lb./ sq. in. ga. with nitric oxide. The mixture was heated various dif?culties, such as expensive starting materials, 45 elaborate reaction vessels, long reaction times, and infor to initiate the reaction, and a maximum temperature of mation of undesirable and hard-to-remove by-products. 100° C. was attained. The pressure increased to a max An object of the present invention is a simple and in imum of 450 lb./sq. in. ga. When further nitric oxide expensive process for the preparation of oximes. Another absorption was no longer apparent, the autoclave was object is a simple liquid phase process for the prepara cooled and vented. The reaction mixture was treated tion of oximes in which the formation of undesirable by as described in Example 1, and 3 parts of diacetyl products is eliminated. Another object is a continuous monoxime (a 10% conversion) was recovered. process for the preparation of oximes. A further object Example 4 is a process for the preparation of oximes from com A mixture of 50 parts of methyl ethyl ketone and 3.4 pounds containing an active methylene group by the 55 action of nitric oxide. parts of cupric bromide was added to an autoclave and the autoclave was pressurized to 150 lb./sq. in. ga. with The objects of the present invention can be accom plished by the reaction of nitric oxide with a compound nitric oxide. The mixture was heated to initiate the re containing an active methylene group at temperatures of action and a maximum temperature of 66° C. was at tained. When the pressure decreased, additional nitric 50 to 150° C. and pressures of 100 to 400 lb./sq. in. ga. 60 in the presence of a variable-valence-metal salt as a cata oxide was introduced to raise the pressure to the initial lyst. Ketones, nitriles, B-keto or B-halo acids and esters, level. At the end of two hours, the autoclave was cooled malonic acid and its derivatives, and arylacetic acids and and vented. The reaction mixture was distilled to remove their derivatives can be nitrosated by the process of this unreacted methyl ethyl ketone (20 parts) and the solid obtained was recrystallized from acetone. Five parts of invention. Variable-valence-metal salts, especially hal 65 ides, cyanides, and sul?des of iron, copper, manganese, diacetylmonoxime (7% conversion, 42% yield) was chromium, cobalt, nickel and tin are suitable catalysts obtained. ' for the reaction. Complex salts of these variable-valence Other ketones which can be nitrosated by the process of metals, such as pyridinium salts and metal salt nitrosyls this invention are acetone, ethyl isobutyl ketone, methyl are also effective catalysts. 70 cyclohexyl ketone, methyl benzyl ketone, cyclohexanone, The following examples illustrate speci?c embodiments acetophenone, and acetylacetone. Both the nitrosation of of the method of carrying out the present invention. It acetophenone and the recovery of the oximinoaceto 2,749,358 3 4 phenone formed must be carried out carefully as the Example 10 oximinoacetophenone is easily cleaved to form benzoic A mixture of 20 parts of phenylacetonitrile, 50 parts acid. of pyridine and 4.2 parts of cupric pyridinium chloride This process also is suitable for the preparation of was added to an autoclave and the autoclave was pres oximes of nitriles having active methylene groups, such surized to 200 lb./sq. in. ga. with nitric oxide. The mix as ethyl cyanoacetate, phenylacetonitrile, nitrophenyl~ ture was heated to initiate the reaction and a maximum acetonitrile, and malononitrile. temperature of 128° C. was attained, at which point the Example 5 pressure reached a maximum of 225 lb./sq. in. ga. When A mixture of 20 parts of phenylacetonitrile, 50 parts 10 further nitric oxide absorption was no longer apparent, by volume of trimethylamine and 2 parts of manganous the autoclave was cooled and vented. Treatment of the sul?de was added to an autoclave at 14° C. and the auto— reaction mixture as in Example 6 produced 24.5 parts of clave was pressurized to 200 lb./sq. in. ga. with nitric ot-oximinophenylacetonitrile (98% conversion and yield). oxide. The mixture was heated to initiate the reaction Example 11 and a maximum temperature of 104° C. was attained, at A mixture of 20 parts of phenylacetonitrile, 20 parts which point the pressure was 225 1b./sq. in. ga. When of pyridine and 4 parts of Roussin’s black salt further nitric oxide absorption was no longer apparent, the autoclave was cooled and vented. Treatment of the mixture as in Example 1 produced 0.5 part of unreacted was added to an autoclave and the autoclave was pres 20 phenylacetonitrile and 24.5 parts of a-oximinophenyl surized to 300 lb./sq. in. ga. with nitric oxide. The mix acetonitrile (98% conversion, 99% yield). ture was heated to initiate the reaction and a maximum Example 6 temperature of 115° C. was attained. The pressure reached a maximum of 315 lb./sq. in. ga. After two A mixture of 20 parts of phenylacetonitrile, 50 parts 25 hours, the autoclave was cooled and vented. Treatment by volume of trimethylamine and 2 parts of cupric chlo of the reaction mixture as in Example 6 produced 13 ride was added to an autoclave at 12° C. and the auto parts (52% conversion) of a-oximinophenylacetonitrile. clave was pressurized to 212 lb./sq. in. ga. with nitric oxide. The mixture was heated to initiate the reaction Example 12 and a maximum temperature of 116° C. was attained. 30 A mixture of 30 parts of phenylacetonitrile, 30 parts The pressure increased to 222 lb./sq.
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