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Patented Oct.‘ 11, 1938, 2,133,001 [ .u-Nirao ‘’ STAT‘ ESfP-ATEN OFFICE; "1,183,071 I P ' ' ~ ‘rnoca‘ssss orssrm'rnvc marm HYDIIDOABBO Anderson w. . ' , ~ > wmimo. Pool, can cago, niqasaig'nors to Armour and Company, Chicago, 111.,v a corporation of Illinois . ‘monstrous-“i5,'. x This ‘invention relates‘ to processes of sepa stances and there are other objections.‘ The’most productive source of the lower vnitriles is-the rating aliphatic nitriles from admixtures ‘there , ofwi'th hydrocarbons and it,com'prises processes vhigher fatty acid nitriles because of the ease with which these‘can‘be cracked’to give ‘the de wherein such mixtures are treated with a prefer ential solvent» material for the nitriles to form sired lower nitriles. - But, asstated, the cracked an extract phase containing the nitrile dissolved products contain quantities of hydrocarbons. Consequently we have set ourselves. to the‘ in the solvent and a hydrocarbon phase, the'two 91 phases separated and thenitrile then‘ separated‘ "problem of discovering methods by/which these ‘ . mixtures of nitrilesKand hydrocarbons can.be" ‘ from the extract phase. 10 separated to obtain the nitriles which can' then 10 Recently processes have been described, as in U. S. Patents 1,991,955. 2,033,536/and. 2933537,‘ for/preparing nitriles of relatively low molecular weight from "*nitriles of highv molecular-weight. For example, by methods of pyrolysis higher ali-' phatic 'nitrilesisuch as ‘stearo and palmitonitrile be fractionally distilled if desired. And we have discovered that‘ mixtures of this type can be treated- with preferential solvents in such a man ner that‘ the nitriles are dissolved to the exclu sion of the hydrocarbons. ,-From the extract 15 can be "cracked" to give reaction products con- 1 phase of nitriles and solvent we can then recover taining nitriles having ‘four, live,- ‘six and‘ seven ‘the nitriles andrecover the solvent for re-use. carbonjatoms. The crackingvoperation' can be so Many experiments have ‘been necessary however controlled that nitriles of almost any desired sincev what will or will. not act as ‘a. preferential number of carbon atoms say from six to eleven solvent for such mixtures could notv be deter 20 mined in advance of experiment. Many solvents ' can be prepared from ‘nitriles of higher molecu ' lar weight. In these processesthe reaction prod-. ‘ which might seemingly dissolve the nitriles with? nets are homogeneous liquid mixture'scontain ing various nitriles associated with quantities of aliphatic hydrocarbons. , ‘ I * 'out' affecting ‘the hydrocarbons actually fform homogeneous mixtures, without‘ leading to the formation of stratified layersof hydrocarbon and‘ Because of the pronounced mu. Although the cracked reaction mixtures'have ' nitrile ,many uses as such without further treatment, tual solubility of the nitriles and aliphatic hy- , there are many instances when it is_desirable 'drocarbonamany solvents dissolve the nitrile but to separate the nitriles from the hydrocarbons the nitrile acts ‘as a mutual second solvent for 30 and to then fractionally "distil the separated ‘both hydrocarbon and added solvent; This leads 'niltriles. This will yield substantially pure‘ nit to mutual solution of all constituents‘. Conse-_ so,’ ri es. And the pure nitriles are starting ma.--v quently the search for satisfactory preferential terials, for many organic syntheses ‘since they ' solvents 'has been asdiihcult task and'many un are sources of polar aliphatic, compounds hav expected discoveries have been made; 7 - 35 ing from‘six to about eleven ‘carbon atoms;v V For example, we have discovered that watery Hitherto reactive compounds of. this nature have *not been availableon‘ a commercial‘scaleand at a price ‘which-would enable them to‘be used as; solutions of aliphatic alcohols can- be used sue‘ cess'i’ully provided care is taken to control the 1' quantity of water present. vThus a '75 percent‘, I .in great quantities.‘ In other words, ‘the ‘de-' ‘ solution of methyl alcohol will dissolve the nitrile ‘Y 40 velopment of processes. of preparing nitriles. from but not the aliphatic hydrocarbons present but ~the cheap fatty ‘acid sources has made it possible ' ‘85 percent methyl alcoholforms a homogeneous for us to supply large- quantities ‘of aliphatic solution of alcohol, water, nitriles, and hydro-v compounds having from‘ about five to ten car carbons. ‘ Hence the application of the broad, ‘bon atoms in the allryl group together-‘with a’ old, 'idea. of preferential extraction with a suit ‘highly reactive polar, ‘or CN' group.‘ This means able solvent to. mixtures of the type with which that many aliphatic amines, alcohols and acids. =we~are concerned has notlbeen asimple matter. Moreoverrhaving discovered a suitable prefer ' of from six to ten carbon atoms can be prepared ' p at lowcost. Hitherto these materials have been‘ nentialsolvent which will‘ give an extract con taining nitriles dissolved in the solvent, the next step is the liberation of‘ the’ dissolved nitrile from its stated. mixtures of nitrilesfalone ‘can-be ",theéxtract. Here again many solvents, appar Fseparated ‘readily by fractional distillation. . It entlysuitable .as preferential solvents must be .is dif?cult however to separate mixtures-of'the discardedbecause’of the difficulties iniseparatin'g I’ vnitriles and hydrocarbons in this manner.‘ Con Jthe nitrile therefrom. What we have ‘sought is 55 stant boiling mixtures are obtained in manyin- ‘ solvents which would dissolve the nitriles but not so expensive that they‘ could not ‘be used in the 50 artS. _ I . V A ' . . ' ,1 I, I 50' h _ v 3 72,138,007 preferential solvents. Among them may be men-‘ aqueous alcohol‘ solution comprises an aqueous tioned aniline, ‘ethyl amine, isopropyl amine,tnor methyl .alcohol solution. > 3.v The process as in claim 1 wherein the ni benzyl amine, secondary butyl ‘amine, isobutyl ‘ true-hydrocarbon mixture isv one composed of the’ amine, normalrbutyl airline,v isoallyl-amine, nor- ' products of cracking relatively high molecular‘ mal propyl amine, diethyl amine, allyl amine, mal amyl amine, dinormal propyl amine, pyri weight fatty acid‘ nitriles. . dine, diallyl amine and cyclohexyl amine. For example 100 parts by volume of the nitrile-hydro carbon mixturevis mixed‘ with 100’ parts .by vol ume of aniline and the-mixture cooled to 0°v C. . 4. The process as in claim 1 wherein the aque , ous alcohol solution is an aqueous methyl alco-- " hol solution and‘. the nitrile-hydrocarbon mixture’ is one composed oi the products of cracking rela 10V tively high molecularweight fatty acid nitriles. This gives an upper layer consisting of ‘toy parts _, of hydrocarbons containing 0.5 percent nitrogen‘ _ and a lower layer composed of ‘160 parts by, vol ume containing aniline and nitriles.. To this lower layer we vadd dilute hydrochloric. acid solu‘-, tion until the nitriles separate out. This gives 5. The processor separating aliphatic nitriles from mixtures thereof vwith aliphatic hydrocar bons which comprisesextracting the nitrile-‘hy ' drocarbon mixture with I an aqueous aliphatic 15 ~ alcohol solution or about 75 percent‘ strength, ~ separating an extract composed of nitriles and us 60 parts of a nitrile fraction containing 5‘per cent of nitrogen. The aniline can be recovered ' the alcoholic solution from the hydrocarbon for reuse by treating the solution of aniline hy-V layer, extracting the hydrocarbon layer with an " ' drochloride with dilute caustic soda. ‘ ' I aqueous alcohol having about 80 percent strength I» separating ‘the hydrocarbon layer from the ex tract. layer, extracting the hydrocarbon layer, ‘s In the appended claims we denote the\layer oi 'nitriles dissolved in the preferential solvent 'as the extract phase. ' . with ,. an aqueous alcohol ' of. about 85 percent ~ In, our co-pending application, Serial No. 169,-’ strength, separating the hydrocarbon layer from 2'72, we have more particularly claimed the use the extract layer, and recovering nitriles from" 25 of carboxylic acids for separating nitriles and J said alcoholic extract layers, by adding water hydrocarbons‘; in our co-pending application, Se 6. The process asinlclalm 5 wherein the alco- ' rial No. 169,273, we have more particularly 3 claimed the use of amines for separating nitriles. )hol is methyl alcohol. 30 and hydrocarbons; and in our application, Serial . . 7. The process as in claim‘ 5 wherein the 30v nitrile-hydrocarbon mixture is one composed of. No. 169,328, we have more particularly the use of phenols ioriseparating nitriles and - the products oi! cracking relatively high molecuj: .thereto. ' , - ‘ ' / hydrocarbons. I > . lar weightiatty-acid nitriles. ' Having thus described our invention what; we claim is‘: ' i , l 1. The process voi! separating aliphatic hitriles ' from mixtures thereof with aliphatic hydrocari _ . . -' 8. The process as inclaim 5 wherein the alco Qhol is methyl alcohol and the nitrlleehydrocar n mixture is one'composed oi! the products or I zgacking relatively'high ‘molecular weight fatty bons which ‘comprises extracting the ,nitrile-hyév ‘ drocarbon mixtures with an aqueous aliphatic‘ al- 1. 40 cohol solution having a strength oi! more‘ than ~ 60% and less than.85% to dissolve thenitriles but not dissolve substantial amounts of the hy drocarbons, separating the extract phase from acid nitriles. , p ,. ' 9‘._In the process of separating aliphatic ni trlles ‘mixtures thereof with aliphatic hy drocarbons; the 'step comprising extracting the mixture with an aqueous aliphatic alcohol solu-' tion which ‘will dissolve the nitriles but notdis the hydrocarbon phase, adding water to 'the ex- I solve substantial amounts of the hydrocarbons. tract phase to liberate the nitriles therein. as a . ' layer, and separating the nitrile» layer from the aqueous alcoholic layer. ‘ ‘ 2. The process as in claim 1, wherein‘ .10. The processas in claim 9 wherein the al cohol is-methyl alcohol. NW.RAIBTON. ‘ ' wnnsuo. roon . 45. "