US2104407A - Manufacture of aryl amines - Google Patents

Description

l halides, and (2) the action of alkyl halides upon reagents as Sulfuric acid, phosphoric id, alumi- Patented Jan. 4, 1938 UNITED STATES PATENT OFFICE MANUFACTURE or ARYL AMIINES Charles L. Thomas, Chicago, 111., assignor to Universal Oil Products Company, Chicago, 111., a corporation oi Delaware No Drawing. Application September 23, 1933, Serial No. 690,761

Claims. (01. 260-1305) I This invention relates more particularly to covered by crystallization from suitable solvents, the manufacture of aryl amines containing alkyland the nitro bodies are then reduced, for examsubstituting groups in the nucleus. pie, with iron powder and hydrochloric acid, to

In a more specific sense the invention has refform the desired toluidine. The course of the 5 erence to an improved process for producing reactions in these two general steps is indicated 5 alkylated taryliamiaiiies whereby the number of by the following equations: separa e s eps 5 re uced and the yields of alkylated products are considerably higher than those CH3C5H5+ O= =-CH C H,NO H O gflaainable by methods at present known in the 32% nitm'wl'mls m The aryl or aromatic amines, which term is used a 4 z+3H2r CH C I-l Nl-l,+2H,0

in its broadest sense to include mono or polymlmdues nuclear ring hydrocarbons containing any num- Another method of producing toluidines from her of amino groups, constitute an important toluol consists in first halogenating the ring and class of compounds on account of their alkaline then converting the h o n e p d into reaction which enables their ready solution in the amine by treatment with ammonia under acids such as sulphuric, phosphoric and hydropressure. The steps in this process are shown chloric acids, which solutions may be madethe by the following equations: starting point for the manufacture of different compounds, particularly the aniline dyes which gfig gk i i fi ig gg are of great'commercial importance. The arorine toluol chl io matic vamines are also the base materials for the manufacture of a large number of special syn- +H thetic chemicals such as various drugs, flavoring amtoluidino materials, perfumes, antiseptics, etcetera. "101118 To deve op the character f e present p A third method or manufacture consists in ess as a p v t v older processes a sulfonating the toluol with strong sulfuric acid ri f m nti n will be m de f h steps n some and then treating the alkaline sulfonate with of h m n ra y wn and commonly used sodamide according to the following equations: methods of' manufacturing the alkylated aryl amines which constitute its desired product. CHacaHs+HZSO4=CH3CGHO3H+H2O The manufacture of alkylated aryl amines wlmlsumm add such as, for example, the toluidines which are shnplest members of this class may be accom- CH3C6H4SO3N3+N3NH2=CH3C6H4NH2+N32SO4 plished (1) by the successive alkylation and Sodemids toluidino aminization of the benzol'ring, (2) the methyla- S tion of aniline or (3) the aminization of toluol. This method is iflic l and dangerous n These steps in many cases conflict so that yields count of the use of sodamide which reacts exof toluidines representing the general class of plosively with water which may accidentally be alkylated aryl amines is too low for the process present. to be of any economic Value- Considerable difficulties are encountered in di- 49 In regard to the manufacture of alkylated rectly alkylating aromatic amines with olefins matics' these may be produced by several meth' owing to their reactivity with the catalytic agents examples of which are: (1) The action of employed which are usually of an acid or metalsodium-on molecular mixtures of alkyl and aryl lie chloride character and may comprise such aromatics in the presence of aluminum and simimum chloride etcetem For example, aniline lafly acting chlorides readily reacts with sulfuric acid, phosphoric acid, one method of making alkylated aryl amines hydrochloric acid, aluminum chloride, etcetera, is exemplified by the production of tomldmes to form water, alcohol or ether insoluble addifmm i gfifig g gf $31 52: 2; tion compounds and in the case of sulfuric acid zigii i f ig f T011101 is fir t also undergoes a certain amount of sulfonation trated by a. mixture of sulfuric and nitric acids d pe d ng upon the conditions of treatment.- In under proper conditions for forming maximum he present process the alkaline characteristics yields of mono nitro toluols, which are then reof aryl amines are neutralized prior to alkylating so that the common alkylating catalysts may be employed with good results.

In one embodiment the invention comprises the manufacture of alleviated aryl amines by the following steps: (1) Treatment of aryl amines with acetic acid to form acyl derivatives, (2) treatment of the acyl compounds with olefins in the presence of acid or metal salt catalyst, (3) hydrolysis of the alkylated acyl products to form alkylated aryl amines and regenerate acetic acid for reuse.

The three steps comprised in the present process are typified by the following equations which show the use of the simplest base compounds and typical catalytic and hydrolyzing reagents:

(1) CsH5NH2+CH3COOH= aniline acetic acid CsHsNHCHaCO-l-HzO acetanilide (2) CcHsNHCHaCO+C2H4=CsH5CeH4NHCH3CO ethylethyl acetanilide (3) C2HsCsH4NHCH3CO+H20= C2H5CsH4NH2+CHaCOOH ethyl aniline acetic acid Step (1) may be effected by using glacial acetic acid, acetic anhydride or acetyl chloride, with suitable variations in operating and treating conditions which are generally well known in theduced to a suitable point, usually in the neighborhood of 0 to 40 C. and either a single olefin or a mixture of olefins such as may be present in the hydrocarbon gas mixtures produced in oil or gas cracking processes is introduced into the acid solution. To insure efiective and complete action the solution should be mechanically agitated.

After completion of the alkylation the alkylated compound may be recovered either by diluting the acid with water, which throws the compound out of solution, or by extracting the acid with some suitable solvent such as, for example, carbon tetrachloride, ortho dichlorobenzol, etcetera, the desired compound then being recovered by boiling off the solvent.

A generally similar procedure to that outlined above may be followed 'with ortho phosphoric acid using concentrations from approximately 90 to 100%.

When using such alkylating catalysts as aluminum chloride which is solid at the preferred low temperatures employed, the alkylation may be aided by using various solvents which are inert to the compounds undergoing reaction and suf-- ficiently fluid. Examples of such solvents are carbon tetrachloride, ethylene dichloride, ortho dichlorobenzene, chloroform, nitro benzol, etc. The procedure when using solvents consists in dissolving acyl-aromatic amines in the solvent,

adding a finely divided metal chloride such as,

in olefin-containing gas until the absorption of olefins indicates that the desired degree of alkylation has taken place. The insoluble metal salt and any sludge reaction products are then allowed to settle, the solution of alkylated compound is decanted or filtered and the product recovered as before as a residue from the evaporation of the solvent. The alkylated acyl aromatic amines thus obtained are then subjected to hydrolysis with caustic alkalies to remove the acyl group and produce the desired aromatic amine.

A number of different catalytic reagents both of an acid and a saline character are mentioned above but the process is not limited to the specific reagents enumerated but may employ any catalyst of suitable condensing activity. The alternatives, however, will each exert its own peculiar eifect upon the speed and course of the reactions in any given case so that they are not to be considered as exact equivalents.

The present process in one of its special application makes possible the production of alkylated derivatives of the nitrogen bases which ocour in the tars produced by the distillation of various naturally occurring carbonaceous materials such as, for example, coal, lignite, peat, shale, etcetera. Without the step of acetylating the aromatic amines, their alkylation would be impossible by ordinary methods on account ofthe formation of stable and insoluble compounds with strong acids such as sulfuric and phosphoric acids and with condensing salts such as aluminum chloride.

The invention is not limited to the use of acetic acid in the first step as previously shown, but homologs of this acid such as propionic acid, butyric acid, etcetera, may be employed and also benzolc acid and its homologs. Thus, after the first step of the process compounds of the following character may be alkylated: Acetanilide, acetnaphthylamines, acetanthraquinoneamines, benzanilide, acet-toluidines, diacetbenzidine, etcetera.

In the second step of the process any olefin or mixture of olefins may be employed such as, for example, ethylene, propylene, the butylenes, amylenes, etcetera, and also compounds of a mixed olefinic-aromatic character such as indene and styrene.

The following examples are offered as illustrations of the results obtainable by utilizing the reactions comprised within the scope of the invention:

Example 1 100 parts by weight of acetanilide (produced by the direct interaction of aniline and acetic acid) is dissolved in approximately 400 parts by weight of carbon tetrachloride, and to the solution about 100 parts by weight of anhydrous aluminum chloride is added. The solution is then treated by introducing ethylene gas until a point is reached where the absorption rate is substantially zero.

The aluminum chloride sludge is settled, the carbon tetrachloride is distilled off and the recovered alkylated acetanilide then hydrolyzed to produce a mixture of ethyl anillnes, the yield being between 85 and 90% of the theoretical corresponding to the production of 77 parts by weight of the alkylated amine.

Example 2 100 parts of acetanilide is dissolved in about 400 parts by weight of 100% phosphoric acid.

After warming to 40 C. to hasten solution, cooling is applied to maintain, the temperature at approximately 30 C. during the introduction of gaseous propylene. After substantially complete saturation with propylene, the acid solution is diluted with about 6 volumes 01' water and extracted with carbon tetrachloride, the steps from this point being similar to those indicated in Example 1.- The yield in this case is 85% of the theoretical and consists of 85 parts by weight of a mixture of isopropyl anilines, principally the ortho and para compounds; Approximately similar results are obtainable using concentrated suliuric acid in place ot phosphoric acid.

Example 3 forming a mixture of butylene propion anilides.

After the reactions are complete the semi-solid sludge is settled and the separated solution is distilled to remove solvent, the alkylated product being then recovered as a residue and subjected to hydrolysis to form the desired alkylated amine which in the present case is a mixture of various butyl anilines, the yield being 88% of the theoretical and corresponding to 59 parts by weight of the desired compounds.

The character of the present invention is disclosed in the preceding specification and its value is shown by a consideration of the numerical data presented but neither is to'be considered in the light of imposing limitations upon its broad scope.

I claim as my invention:

1. A process for alkylating an alkyl-iree aeromatic amine, which comprises treating a primary aryl amine with a mon'o-carboxylic acid to form an acyl derivative, subjecting the acyl derivative to treatment with an olefinic hydrocarbon in the presence oi a condensation catalyst, and hydrolyzing the resultant compound to form the alkylated aryl amine.

2. A process for directly allgylating an alkylfree aromatic amine, which comprises treating a primary aryl amine with a mono-carboxylic acid to form an acyl derivative, subjecting the acyl derivative to treatment with an olefin in the presence a catalyst comprising essentially aluminum chloride, and hydrolyzing the resultant product to form the alkylated aryl amine.

3. A process for directly alkylating an alkylfree aromatic amine, which comprises treating a primary aryl amine with a mono-carboxyllc acid to form an acyl derivative, subjecting the acyl derivative to treatment with an olefin in the presence of a catalyst comprising essentially an inorganic non-oxidizing mineral acid, and hydrolyzing the resultant product to form the alkylated aryl amine.

4. A process for alkylating an allgyl-free aeromatic amine, which comprises treating a primary aryl amine with a mono-carboxylic acid to form an acyl derivative, subjecting the acyl derivative to treatment with an olefinic hydrocarbon in the