US2218587A - Process for producing aliphatic ketone anils - Google Patents

Description

Patented 0a. 22, 1940 UNITED STATES PATENTA OFFICE No Drawing. Application May 25, 1938, Serial N012 09,988- In Germany May 27, .1937

' 3 Claims. (01. 260-566) per cent. It is advantageous to use the distilled The Schiffs base aliphatic 'ketones, the socalled aliphatic ketone-anils, have not hitherto been made by direct condensation of the ketone with aniline. Schiff himself thought that the lretone had no tendency to form an anil. Later authors (Engler, Riehm, Pauly and especially lately Von Knoevenagel) have published communications concerning aceto-anil which do not appear to be in agreement with each other, compareFBerichte 65, 1511 (1932) and Annalen 523 (118) 1936. Recently Montagne and Rousseau (C. R. 196, 1165, Chemisches C'entralblatt 1933, I, 3702) have used as a general method for producing aliphatic ketone-anils a circuitousprocess in which an organic magnesium compound is caused to act in ethereal solution on a fatty acid anilide and the product thus obtained is superheated. The yields of this processare only small and methyl ketone-anil cannot be produced even by this method.

This invention relates to the manufacture of the anils of the aliphatic ketones in a simple manner by direct condensation of the ketone with aniline or its homologue by removing the water produced in accordance with the following equation:

CO+NH:-OeHs O=N-CaH5+HzO R1 R1 not by means ofan agent that binds water used in the mixture but in a mechanical manner without any addition whatever. Such mechanical removal of water produced in the reaction may be achieved by known methods such as are used in analysis, for instance by means of the apparatus of E. Meyer, Annalen, vol. 433, page 331.

By the process of the invention the aliphatic ketone-an ils may be produced rapidly and in good yield. In the case of water-soluble ketones (acetone, ethyl-methyl ketone) in which the separation of the water is complicated by solu-' bility, there is advantageously added to the mass undergoing reaction some benzene or toluene.

The following examples'illustrate the invention, the parts being by weight:

Example 1.- parts of methylisobutyl ketone and 186 parts of aniline are boiled together in the apparatus described in Annalen, vol. 433, page 331. After about 20 hours the reaction is finished, which will be evident from the quantity of water removed (18 parts). The mass is now distilled in a vacuum. The methylisobutyl ketone-anil boils at 107C. under 11 mms. pressure andis a colorless oil. The yield is about 80 aniline for a newsbatch whereby the yieldis somewhat enhanced.

':In like mannerthere can be obtained:

- From aniline and pinacoline the pinacoline-anil,

boiling point 96 to 97 under 11 mm. pressure, From aniline and di-normal-propylketone (butyrone) the di-normal-propylketone-anil, boilingp'oint 119 to under 11 mm, pressure,

From aniline and di-iso-propylketone (isobutyrone) the di-isopropylketo-ne-anil, boiling point 106.5 under 11 mm. pressure,

From aniline and methylnonylketone the meth- -ylnonylketone-anil, boiling point 176 to 178 under 12 min. pressure,

From ortho-toluidine and pinacoline the pinacoline-ortho-tolil, boiling point 105 to 108 under 11 mm. pressure,

From meta-toluidine and pinacoline the pinacoline-meta-tolil, boiling point 111 to 112 under 11 mm. pressure,

From para-toluidine and pinacoline the pinacoline-para-tolil, boiling point 111 to 112 under 11 mm. pressure.

Example 2.'72 parts of ethylmethyl ketone,

186 parts of aniline and 100 parts of benzene are heated together as described in Example 1.

' After about 18 parts of water have been removed,

which is the case in about 12 hours, the mass is worked up by vacuum distillation. The ethylmethyl ketone-anil boils at 87 to 89 C. under 11 mm. pressure and is a colorless oil. The yield is about 65 per cent.

Example 3.60 parts of acetone, 186 parts of aniline and parts of benzene are treated as described in Example 2. The acetone-anil thus obtained boils at 76 to 77 C. under 11 mm. pressure and is a colorless oil which has a great tendency to unite with: 1 mol aniline exothermally and produces a diphenamine-compound (CH3) 21C: (NH CsHa) 2 It is obvious that the invention is not limited to the foregoing examples or to the specific details given therein. Thus, for instance, instead of benzene there may be added to the reacting mixture another compound forming an azeotropic mixture with the water formed during reaction. Compounds of this kind are well known in the art, besides aromatic hydrocarbons aliphatic hydrocarbons or their halogen substitution products, such as carbon tetrachloride, may be enumerated. Preferably water immiscible com-5 pounds are selected for carrying away the water,

so that after condensation of the vapors two layers are formed, from which that part consisting of the organic liquor is reintroduced into the reaction mixture. In this: manner "onlya small amount of such an assistant is necessitated.

The ketone-anils obtainable according to the new process are valuable intermediat products for the manufacture of dyes. They may bereduced according to known processes .to formtertiary amines which may be used per se for manufacturing azo dyes, or they may be transformed into amino aldehydes for the manufacture of, for instance, triphenylmethane dyes.

What is claimed is: 1. The manufacture of aliphatic ketone-anils which comprises condensing an alkyl ketone with more than an equimolecular amount of a primary amine of the benzene series and mechanically removing from the reacting mixture the water produced by the reaction.

2. The manufacture of aliphatic ketone-anils which comprises boiling together an alkyl ketone and more than an equimolecular amount of a primary amine of the benzene series and removing from the reacting mixture the water produced by the reaction by azeotropic distillation.

. 3. The manufacture of aliphatic ketone-anils which comprises boiling together an alkyl ketone and more than an equimolecular amount of a primary amine of the benzene series under addition of a compound forming an azeotropic mixture with water boiling at a lower temperature than the amine and the ketone, and thus removing from the reacting mixture the water produced by the reaction by azeotropic distillation. MARIE LOUISE HOMEYER,

NEE REDDELIEN, Administratrix of the Estate of Gustav Heinrich Reddelz'en, Deceased.