Feb. 19, 1952 D. B. LUTEN, JR., ETAL 2,586,070 PROCESS FOR PRODUCING PHENOLIC DERIWATIVES Filed Nov. 3, 1947

Aromatic Mixture of A and 5

Recycle. Additament and/6r Portion of Product

Addition Product AC Admixed with B b

separator

Desired Derivative A inventors: Daniel B. Luter, Jr. Aldo DeBenedicts by their Attorney 7.54 Patented Feb. 19, 1952 2,586,070

UNITED STATES PATENT OFFICE 2,586,070 PROCESS FOR PRODUCING PHENOLC - DERVATIVES Daniel B. Luten, Jr., and Aldo De Benedictis, Berkeley, Calif., assignors to Shell Develop ment Company, San Francisco, Calif., a corpo ration of Delaware Application November 3, 1947, Serial No. 783,832 13 Claims. (CI. 260-624) 2 This invention relates to a novel process for divided, part being recycled to produce more of the production of derivatives of aromatic organic the addition product, and part being taken as compounds, and to novel compounds produced by the final product. - Said process. Another preferred embodiment of the present In general, aromatic compounds are easily invention contemplates the formation of an ad obtainable from natural or synthetic sources as dition product wherein one component thereof components of mixtures of closely related com is the aromatic compound from which the desired pounds, such as mixtures of isomers. In order derivative may be prepared, while the other com to prepare derivatives from an aromatic com ponent is a material which emerges from the pound contained in such a mixture, it is cus O process substantially unchanged, and, after Sep tomary first to separate the aromatic compound aration of the desired derivative, may be re from the mixture and then to treat or react it cycled in the process. . to form the desired derivative. An alternative A still further preferred embodiment of the method is to treat or react the mixture of ma present invention contemplates the formation of terials to form the desired derivative, which is 5 an addition product wherein one component then separated from the reaction mixture. Both thereof is again the aromatic Compound from of these processes, however, in some instances which the desired derivative may be prepared, are extremely difficult and uneconomical. In while the other component is a material which the first method, for example, it may be prac also forms a valuable derivative during the re tically impossible to separate the aromatic com 20 action. ponent, at least by ordinary procedures, while in The present invention is especially advanta the latter method, compounds other than the de geous where the aromatic compound, from which sired derivative are usually produced, which con the desired derivative may be prepared, is a com Sumes the reactants to no advantage and fre ponent of a mixture of materials from which it quently leaves a difficult problem of separation of 25 cannot be separated except by difficult, laborious the desired derivative. As illustrative of aro and uneconomical methods. For example, if it matic mixtures wherein the Separation of the is desired to prepare 2,4-dimethyl-6-tertiary components presents unusual difficulties are mix butylphenol from 2,4-xylenol, which is usually tures of the isomers of cresols, xylenols, xylenes, a component of a multi-component System of dimethyl naphthalenes, toluidines, xylidines and 30 phenols containing 2,4-xylenol, 2,5-Xylenol and picolines. 2,3-xylenol, it has heretofore been necessary to It has now been found that aromatic deriva separate the 2,4-xylenol and to subsequently tives may be produced economically, convenient butylate the separated 2,4-xylenol, or to butylate ly, and in good yield from multi-component SyS the mixture of materials and then recover the tems containing as a component thereof the aro desired product from the reaction mixture. matic compound to be treated to form the de These methods are difficult and uneconomical. sired aromatic derivative, by mixing said multi In the first method, it is practically impossible component system" with a material capable of to separate 2,4-xylenol from the mixture of ma forming an addition compound with said aro terials by ordinary methods because the boiling matic compound, separating the resulting addis 40 points of the various components are identical, tion product from the other substances of the or practically identical, and therefore it is nec admixture, treating or reacting the addition essary to resort to unusual, difficult and uneco product so as to prepare the desired derivative nomical processes. In the second method, where of the aromatic compound, and recovering said the mixture of xylenols is butylated prior to Sep aromatic derivative. aration, a mixture of products is obtained, where A preferred embodiment of the present inven by a major portion of the butylating agent, such tion contemplates the formation of an addition as isobutylene, may be wasted by the formation product wherein one component thereof is iden of by-products, and the separation of the desired tical with the desired aromatic derivative, and product from the mixture remains difficult. Ac the other component is the aromatic compound cording to the present invention, these difficulties to be treated to form the desired derivative there are overcome in this instance by adding 2,4-di of, separating the addition product from the re methyl-6-tertiary-butylphenol to the mixture of action mixture, and treating the addition prod xylenos and forming an addition product of 2,4- uct to produce the desired aromatic derivative dimethyl-6-tertiary-butylphenol with 2,4-xylenol, in substantially pure form. The product may be as hereinafter described, separating the addition 2,586,070 3 4. product from the remaining mixture, and treat therewith. After mixing the 2,4-dimethyl-6- ing the addition product under alkylating con tertiary-butylphenol with the mixture contain ditions with a butylating agent, thereby butylat ing 2,4-xylenol, the admixture preferably is heat ing the 2,4-xylenol content of the addition prod ed to above the melting point of the addition uct to obtain substantially pure 2,4-dimethyl product, in this instance to above about 46° C., 6-tertiary-butylphenol. Part of the product may and the mixture then cooled, or allowed to cool, be recycled to produce more addition product and whereupon a solid addition product separates, part taken as the final product. This process, which may be filtered or removed by any con which illustrates a preferred embodiment of the venient means. In some instances it is unneces present invention and which is more fully de 10 sary to heat the mixture, cooling being sufficient scribed hereinafter, provides a simple and eco to cause crystal formation, but it is generally nomical process for the production of aromatic preferable to first heat since the resulting crys derivatives from multi-component systems in tals may be more readily filterable. In general, cluding as a constituent thereof the aromatic the System consists of a homogeneous liquid phase compound to be treated, which process obviates until formation of the addition product com the objections to heretofore known methods, as mences. It is sometimes desirable to add a small above-described. quantity of seed crystals of the addition com The existence of addition products between pound to the mixture to aid crystal formation. different aromatic compounds, and between aros The presence of an inert liquid diluent may in matic compounds and other materials, such as 20 the addition products of phenol and alpha naph Somequent instancesseparation aid from crystal the formation system. andOf course,subse thylamine, phenol and para toluidine, and the materials may be heated before mixing, foll phenol and meta cresol has been recognized here lowed by mixing and cooling, as described. The tofore. Such compounds (i. e., compounds of separated addition product, consisting of 2,4- asSociation) or adducts may be considered as 25 dimethyl-6-tertiary-butylphenol and 2,4-xylenol, products of physical association between mole may then be butylated to produce essentially pure cules, as contrasted to the compounds formed 2,4-dimethyl-6- tertiary - butylphenol. Butyla by chemical reaction wherein the identities of the tion may be accomplished by any convenient reactants are lost in the formation of the new means, such as by melting the addition product product. Such addition products, however, have 30 and reacting with isobutylene preferably in the heretofore largely been considered merely as presence of a small amount of an alkylation laboratory curiosities, being prepared usually catalyst such as sulfuric acid, or by dissolving from the two pure components, or from simple the addition product in an inert solvent and mixtures, and their use restricted to simply the butylating. The product is essentially pure 2,4- separation of the addition product and recovery dimethyl-6-tertiary-butylphenol, and may be of the two components therefrom. divided, part being taken as the product and part In many instances, the formation and separa being recycled to form more addition product tion of addition products in accordance with the with 2,4-Xylenol. Similarly, 2,4-xylenol may be present invention provides new compositions of converted to a desired 2,4-dimethyl-6-alkyl matter which are useful and novel per se, but phenol by first forming an addition product the principal object of the invention, in addition thereof with a portion of such desired 2,4-di to the production and separation of addition methyl-6-alkyl-phenol, separating from other products, is the treatment or reaction of the ad dition products to form a desired derivative of materials, and then alkylating with an alkylating the aromatic component or components of the agent corresponding to the alkyl radical of said addition product. This procedure, as provided desired 2,4-dimethyl-6-alkyl-phenol. by the present invention, possesses many ad In a Substantially identical manner other ad vantages over the processes heretofore taught, as dition products may be formed, separated and above-described. The main use of the addition reacted in accordance with the present invention. products produced in the process of the present For example, in another preferred embodiment invention is to provide for the preparation of of the present invention, 2,4-dimethyl phenol the desired aromatic derivative, but other uses may be employed to form an addition product include the separation of a specific component with meta cresol in a mixture of cresols, or meta, from a multi-component mixture, from which the Cresol may be employed to form an addition individual combonents may then be separated, product with 2,4-xylenol in a mixture of xylenols, usually by distillation. A still further advantage 5 5 and the addition product, as produced in either is in the ease of handling a solid product instead case, Separated and treated or reacted to produce of two normally liquid materials, whenever the a derivative thereof, for example it may be bu two components may be employed in a single tylated to form a mixture of 2,4-dimethyl-6- processor operation. tertiary-butylphenol and 2,4-ditertiarybutyl-5- In the preparation of 2,4-dimethyl-6-tertiary 60 methylphenol, which products are easily Separa butylphenol, as hereinbefore described, which ble and both valuable. illustrates a preferred embodiment of the present As above stated, a further preferred embodi invention, it has been found that various amounts ment of the present invention is the formation of 2,4-dimethyl-6-tertiary-butylphenol may be of an addition product between an aromatic com added to mixtures of xylenols to produce the ad 65 pound from which a desired derivative is to be dition product between it and 2,4-xylenol. It is prepared and a material which is substantially believed, in this instance, that one of three addi inert in the subsequent treatment or reaction. tion products, wherein the mol ratios of the come The formation of an addition product between ponents are 1:2, 1:1 and 2:1, respectively, may meta Cresol, which may be contained in a mixture. be formed. In general, it is preferred to add 70 of cresols, and urea illustrates this embodiment. Sufficient 2,4-dimethyl-6-tertiary-butylphenol so The meta cresol-urea addition product Separ that the quantity thereof present is about one rates from the mixture in the form of crystals mol per mol of 2,4-xylenol. However, more or which may be separated by filtration, or other. less may be added, and good results achieved 5 orSuitable reacted means, to form and a derivativethe addition of theproduct meta treated cresol. 2,586,070 5 6 which derivative is easily separable from the scribed methyl and polymethylphenols, naphthyl urea, and the urea, may be recycled in the proc amines and alkylated naphthylamines, toluidines, ess. In a substantially identical manner pala, benzonitrile and alkylated benzonitrile, Such as cresol may be separated from mixtures of cresols 2,4-dimethyl benzonitrile, or homologues thereof, by forming an addition product with Oxalic acid, such as the ethyl, propyl, butyl, amyl and hexyl the addition product separated and reacted or homologues, benzoic acid, alkylated benzoic acid, treated to form the desired derivative of para such as 2,4-dimethylbenzoic acid, Xylidines, cresol. The derivative is then separated from the picolines, and the like. In general, the aromatic oxalic acid, which may be recycled in the process. derivatives contemplated by the present invention. A special advantage of such processes, in accord are prepared from aromatic compounds having ance with the present invention, is the fact that attached to the aromatic ring a polar group, Such the non-aromatic constituent of the addition as the -OH, -NH2, -CN, and -COOH groupS, product may serve as a catalyst in the reaction since these compounds generally readily react to employed to produce the desired derivative. For form addition compounds with suitable addita example, in the above process Oxalic acid catalyzes 5 ments, and such compounds commonly occur in the alkylation of para cresol. mixtures of materials from which they may be The present invention may be better understood separated only with difficulty by the usual pro from a consideration of the accompanying draw cedures. The additament may also advanta ing which is made a part of this specification and geously be an aromatic compound containing a in which the sole figure is a flow diagram repre similar polar group attached to the aromatic senting one embodiment of the invention. Re nucleus, but may belong to other classes of con ferring to the drawing, an aromatic mixture in pounds, as herein described. The above-men cluding as components thereof the aromatic Con tioned polar compounds, which may be separated pound A, whose derivative A' is the desired prod from mixtures containing them and treated in ac uct, and at least one other component B, is fed cordance with the present invention, may also be into mixer via line 2, and additament C, capable employed as additaments for forming addition of forming an addition product with A, is fed into products with other polar compounds. Thus, pre the mixer via line 3. The mixture may conven ferred additaments for forming addition products iently be heated while in the mixer as by means with 2,4-xylenol are the 2,4,6-trialkylphenols, and of steam introduced into a heating jacket 4. The 30 generally preferred additaments for forming ad mixture of A, B and C is transferred via line 5 dition products with 2,4-dialkyl phenols are the to cooling vessel 6, adapted to be cooled by any 2,4,6-trialkylphenols wherein preferably no alkyl suitable means where the addition product AC group contains more than 6 carbon atoms. Other is formed. The mixture of A C and B is passed polar compounds, as above-described, may be em via, line 8 into a separator 9, such as a centrifugal ployed with good results, and still other addita filter. B is separated from the addition product ment materials, as herein described, may be en AC and removed via line O. B may be recycled ployed. In a similar manner, preferred addita to mixer via line , since it may be employed ments for separating polar aromatic compounds, as a diluent, and may contain some unreacted A and especially those polar compounds containing or C which may be recovered by recycling. The 3) substituent alkyl groups in the 2 and 4 positions, addition product AC is transferred via line are the 2,4-dimethyl-6-alkylphenols, or generally into a reactor 2 and reactant D is introduced the 2,4,6-trialkylphenols wherein preferably no therein via line 3. Compound A, from the addi alkyl group contains more than 6 carbon atoms, tion product AC, and reactant D react to form but other polar compounds, as above-described, the desired derivative A', and the mixture of A' 4 s may be employed with goods results, and still other and C is passed via lines A and 5 into a sepa additament materials as herein described, may be rator 6 wherein the desired derivative A' is sepa employed. In general, preferred additaments for rated and removed via line T. Separated addita separating alkyl phenols are other alkyl phenols ment C is recycled to the mixer via lines 8 and having a different number of substituent alkyl 3. In the preferred process of the present in () groups, wherein none of the alkyl groups contain vention, the desired derivative A' is identical with more than 6 carbon atoms, such as the employ additament C, so that, in this case, the product ment of a mono-, tri-, or tetraalkyl phenol, or from the reactor 2 is the pure material A' (or honologues thereof, to Separate a dialkyl phenol. C), so that the desired derivative may be taken In general, a solid addition compound or prod directly from the reactor via lines 4 and 20, or uct will be formed by the process of the present all or any part thereof may be directly recycled invention, which may be separated by filtration, via lines 9, 8 and 3. or the like, but in some instances a liquid addi For purposes of simplicity, heat, exchangers, tion product, immiscible in the mixture, may be pumps, temperature controls, and control means, produced, which also may be separated and the proper placement of which is evident to those treated as described. It is preferred to carry out skilled in the art, have been largely omitted. the process of the present invention so that Only It is now evident that the process of the present the aromatic compound, the derivative of which invention may be employed when an aromatic is desired, will form an addition product with the compound, a derivative of which is the desired added component. However, in some instances product, forms or can be made to form an addi two or even more addition products may be tion product with a selected additament, which formed, especially where complex multi-com addition product separates or can be separated ponent mixtures are involved. The formation of from whatever other components may be present undesired addition products may be largely elimi including adducts between other mixture com nated by proper choice of the amount of the com ponents and the additament which may beformed 70 ponent added (additament) to form the addition under some reaction conditions. The present in product (adduct), and by proper temperature con vention may be applied to the preparation of de trol during the formation of the addition prod sired derivatives of various aromatic compounds, ucts. Even if such undesired addition products such as derivatives of the ethyl, propyl, butyl, are formed, they usually do not interfere with the amyl and hexyl homologues of the herein de- 75 present process, and the desired derivatives may 2,586,070 7 8 beformed and is easily separable from the reac derivative separated therefrom. The cineole may tion mixture. Where desirable, a diluent may be be recycled in the process to form more addition : employed, for example where filtration or other product. Separation of the addition product would other When desired, the addition product of cineole :Wise be difficult. 3. and 2,4-xylenol may be treated to form valuable The following specific examples are presented derivatives of both 2,4-xylenol and cineole in the to further illustrate the present invention, which same operation, which derivatives may be easily is not to be considered as limited thereby. Separated, as by distillation. Eacample I The invention claimed is: 0. 1. As a new composition of matter, a Solid ad Two hundred fifty parts by weight of a mixture dition product of a dialkyl phenol with another containing various Xylenols, including 2,3-xylenol, alkylphenol having a different number of sub 2:5-Xylenol. 2,6-Xylenol, 3,5-xylenol, and contain stituent alkyl groups, said addition product be ing about 55-60% by weight of 2,4-xylenol was ing Selected from the group consisting of a solid mixed with about 200 parts by weight of 2,4- 5 addition product of 2,4-xylenol and meta-cresol dimethyl- 6 - tertiary-butylphenol. The mixture and a solid addition product of 2,4-xylenol and Was Walmed Slightly and then allowed to cool to 2,4-dimethyl-6-tertiary-butylphenol. room temperature. About 200 parts by weight of 2. As a new composition of matter, a solid Crystals of the addition product of 2,4-xylenol and addition product of 2,4-xylenol and meta-cresol. 2,4-dimethyl- 6 - tertiary-butylphenol formed at 2K) 3. As a new composition of matter, a solid room temperature and was recovered by centrifu addition product of 2,4-xylenol and 2,4-dimethyl gation. The yield may be increased by cooling to 6-tertiary-butylphenol. ilower temperatures. This addition product repre 4. The process of preparing derivatives of 2,4- sentS a new composition of matter from which Xylenol from mixtures of xylenols including as a the two components may be recovered, as by dis component thereof 2,4-xylenol, which comprises tillation, or which may be reacted or treated to mixing Said mixture of xylenols with 2,4-dimeth form derivatives of either, or of both, of the coin yl-6-tertiary-butylphenol and forming an addi ponents. The addition product was recrystallized tion product of 2,4-xylenol and 2,4-dimethyl-6- from isooctane and the melting point determined tertiary-butylphenol, separating said addition as-45.7°.C. 30 product from the other substances of the admix The addition product may be butylated by melt ture, butylating said addition product to form ing and contacting with isobutylene in the pres Substantially pure 2,4-dimethyl-6-tertiary-butyl -ence of a Small amount of sulfuric acid catalyst phenol, and recycling a portion of the 2,4-di to form Substantially pure 2,4-dimethyl-6-terti methyl-6-tertiary-butylphenol to form additional ary-butylphenol. addition product. Eacample II 5. The process of preparing alkyl derivatives of One thousand parts by weight of a mixture of 2,4-Xylenol from mixtures of xylenols including Xylenols, as described in Example I, containing as a component thereof 2,4-xylenol, which com about 65% of 2,4-Xylenol Was mixed With about prises mixing Said mixture of xylenols with 2,4- 950 parts by weight of 2,4-dimethyl-6-tertiary 40 dimethyl-6-tertiary-butylphenol and forming an butylphenol, which corresponds to a mol ratio of addition product of 2,4-xylenol and 2,4-dimethyl one to one of 2,4-xylenol to 2,4-dimethyl-6-ter 6-tertiary-butylphenol, separating said addition tiary-butylphenol. The mixture was warmed and product from the other substances of the admix the homogeneous liquid mass then cooled to yield ture, alkylating said addition product with an about 920 parts by weight of the addition product 5 alkylating agent for phenols and having from 1. at 20° C. which was separated by centrifugation. to 6 carbon atoms to form the desired alkyl de On cooling the residual liquid mixture to 15° C. rivative, recovering the 2,4-dimethyl-6-tertiary an additional quantity (about 75 parts by weight) butylphenol from the resulting reaction mixture of the addition product was recovered, but further and recycling at least a portion of the 2,4-di cooling did not yield additional significant quan methyl-6-tertiary-butylphenol to form additional tities of the desired addition product. addition product. About one hundred parts by weight of the prod 6. A process for the production of a desired uct (adduct) was heated to 90° C. and contacted alkyl phenol compound of the general formula: with about 20 parts by weight of isobutylene in OH the presence of one part by weight of 96% sulfuric 5 5 acid. The reaction was carried out at constant volume, the temperature being held at about 90° C. About 100 parts by weight of 2,4-dimethyl-6- tertiary-butyl phenol was recovered, indicating a conversion of about 70%. Higher conversion may be obtained by employing an excess of isobutylene wherein X1, X2 and Xa each represent an alkyl in the reaction. group of from 1 to 6 carbon atoms, which com Eacample III prises mixing a multi-component system contain ing as a component thereof an alkyl phenol com About thirty-five parts by weight of a mixture pound of the general formula: of xylenols containing about 60% of 2,4-xylenol Was mixed With a quantity of Cineole Sufficient to OH form an addition compound containing 2 mole cules of the 2,4-xylenol to one of the cineole. The mixture Was Warned and then cooled to about -10° C. and about 15 parts by weight of the solid addition product recovered by centrifugation. This addition product may be treated or reacted k, to form a derivative of the 2,4-xylenol, while the wherein Xi and X2 each represent an alkyl group cineole remains substantially unaffected, and the 75 as above defined, with an alkyl phenol addita d

2,586,070 10 ment capable of forming an addition product phenols and having not more than 6 carbon therewith, separating said addition product from atoms; recovering from the resulting reaction other Substances in the resulting admixture, mixture Said desired alkyl derivative of 2,4-di alkylating said addition product to form the de alkyl phenol and recycling at least a portion of sired compound, separating the desired com Said 2,4,6-trialkyl phenol to form additional solid pound and recycling at least a portion of said addition product. additament to form additional addition product 12. The process of preparing derivatives of a with said alkyl phenol of the general formula methyl phenol which comprises: mixing a multi OE component System containing as a component 0 thereof a 2,4-dialkyl phenol wherein at least one X of the alkyl groups is a methyl group, the re maining alkyl group containing from 1 to 6 car bon atoms, with a 2,4,6-trialkyl phenol wherein the 2- and 4- alkyl radicals are identical respec k, S tively with those of said 2,4-dialkyl phenol and as described hereinbefore. wherein the alkyl group in the 6- position con 7. A process for separating 2,4-xylenol from a tains from 1 to 6 carbon atoms; forming an addi mixture of Xylenols containing as a component tion product of said 2,4-dialkyl phenol and said thereof 2,4-xylenol, which comprises adding to 2,4,6-trialkyl phenol; separating said addition Said mixture 2,4-dimethyl - 6 - tertiary - butyl 20 product from the other substances in the result phenol, forming a solid addition product of 2,4- ing admixture; alkylating said addition product Xylenol and 2,4-dimethyl-6-tertiary-butyl-phenol with an alkylating agent which yields an alkyl and separating said solid addition product from group identical with said alkyl group present in the resulting. admixture. the 6- position of said 2,4,6-trialkyl phenol, so 8. A process for separating 2,4-xylenol from a 25 as to form substantially pure said 2,4,6-trialkyl mixture of xylenols containing as a component phenol; separating at least a portion of said 2,4,6- thereof 2,4-xylenol which comprises adding to trialkyl phenol from the reaction mixture and re said mixture 2,4-dimethyl-6-alkyl phenol, form cycling said portion of said 2,4,6-trialkyl phenol ing a solid addition product of 2,4-xylenol and to form additional addition product with a fur Said 2,4-dimethyl-6-alkyl phenol and separating 30 ther portion of said 2,4-dialkyl phenol. Said Solid addition product from the resulting ad 13. A process for the preparation of a desired mixture. . 2,4,6-trialkyl phenol derivative of a 2,4-dialkyl 9. The process of preparing derivatives of 2,4- phenol which comprises: adding to a multi-com Xylenol from a mixture of xylenols including as a ponent system containing as a component there Component thereof 2,4-xylenol, which comprises : 3 of a 2,4-dialkyl phenol whose derivative is de mixing said mixture of xylenols with a 2,4-di sired, an oxygen-containing aromatic compound methyl-6-alkyl phenol capable of forming a solid selected from the group consisting of cineole and addition product with 2,4-xylenol and forming a 2,4,6-trialkyl phenol in which the 2- and 4 an addition product of 2,4-xylenol with said 2,4- alkyl radicals are identical respectively with those dimethyl-6-alkyl-phenol, separating said addition of said 2,4-dialkyl phenol, no alkyl group in said product from the other substances of the admix 2,4-dialkyl phenol and 2,4,6-trialkyl phenol hav ture, alkylating said addition product with an ing more than 6 carbon atoms; forming a solid alkylating agent which yields an alkyl group addition product of said 2,4-dialkyl with said identical with said alkyl group present in the 2,4- oxygen-containing aromatic compound; Sepa dimethyl-6-alkyl phenol, to form substantially rating said solid addition product; alkylating said pure 2,4-dimethyl-6-alkyl-phenol, and recycling 45 solid addition product with an alkylating agent a portion of the 2,4-dimethyl-6-alkyl phenol to for phenols and having not more than 6 carbon form additional addition product. atoms; recovering from the resulting reaction 10. A process for the preparation of a desired mixture said desired alkyl derivative of 2,4-di 2,4-dimethyl-6-alkyl phenol from a mixture of alkyl phenol and recycling at least a portion of Xylenols containing 2,4-xylenol Which comprises; 60 said oxygen-containing aromatic compound to adding cineole to said mixture; forming a solid form additional solid addition product with a fur addition product of 2,4-xylenol with cineole; al ther amount of said 2,4-dialkyl phenol. kylating said addition product with an alkylating DANIEL B. LUTEN, JR. agent which yields an alkyl group identical with ALDO DE BENEDCTIS. the alkyl group present in said desired 2,4-di 53 methyl-6-alkyl phenol; separately recovering REFERENCES CITED from the resulting reaction mixture substantially The following references are of record in the pure said desired 2,4-dimethyl-6-alkyl phenol and substantially pure cineole and recycling at file of this patent: least a portion of the recovered cineole to form 60 UNITED STATES PATENTS additional solid addition product. Number Name Date 11. A process for the preparation of a desired 1830,859 Schotte et al. ------Nov. 10, 1931 2,4,6-trialkylphenol derivative of a 2,4-dialkyl 1980,384 Comte ------Nov. 13, 1934 phenol which comprises; adding to a multi-com 1980,385 Comte ------Nov. 13, 1934 ponent system containing as a component thereof 65 1980,901 Bentley et al. ------Nov. 13, 1934 a 2,4-dialkyl phenol whose derivative is desired, 2,042,331 Carswell ------May 26, 1936 a 2,4,6-trialkyl phenol in which the 2- and 4 2,321,036 Luten, Jr., et al. ----- June 8, 1943 alkyl radicals are identical respectviely, with 2,432,064 Cislak et al. ------Dec. 2, 1947 those of said 2,4-dialkyl phenol, no alkyl group 2,435,087 Luten, Jr., et al. ----- Jan. 27, 1948 in said 2,4-dialkyl phenol and 2,4,6-trialkyl 70 phenol having more than 6 carbon atoms; forms OTHER REFERENCES ing a solid addition product of said 2,4-dialkyl Morgan et al., Jour. Soc. Chem. Ind., vol. 54, phenol with said 2,4,6-trialkyl phenol; separating 19T-25T (1935). (Patent Office Library.) said solid addition product; alkylating said solid Fields et al., Ind. Eng. Chem., vol. 32, 489-96 addition product with an alkylating agent for 75 (1940). (Patent Office Library.)