Paterated May 16, 1939 2,158,518

UNITED STATES PATENT OFFICE 2,158,518 PRODUCTOR OF AROIWATEC, ADEHYDES Water Caristian Weiy, New Brunswick, N. J., assig o' to E. E. du Pont de Nemour's & Com pany, Wiiiri gigsa, Dei., a corporation of De 3y2'e Reg Fei'awing. Application November 25, 1936, Seriai No. 112,710 A Ciaiians. (C. 260-599) This invention relates to the production of atinoSpheres), I have succeeded in stepping up aromatic aidehydes. More particularly, this in the yield to as high as 18%, but this is still Vention relates to the production of para-alkyl far too low to make the process practical from aldehydes of the general formula. the commercial viewpoint. That my experiences above have been shared 5 by other's is evident from the fact that although Cuminic aldehyde is a valuable perfume inter Wherein R is an alkyl radical containing from l mediate, and therefore in industrial demand, the to 8 carbon atoms, or more. ite!"ature is replete with proposed alternative 0. It is an object of this invention to provide a proceSSes for manufacturing this valuable con 0 novel and efficient netilod foil preparing aide pound Without making use of the direct intro hydes of the above general formula. It is a duction of the Carbonyl group by means of car further' object of this invention to provide a bon monoxide. ninethod for the imanufacture of para-alkylated The major difficulty with the Gatterinainn syn 5. aromatic aldehydes which enables one to start thesis, When applied to alkylated benzenes coin 5 with cheap initial materials. Other and further taining an alkyl group with more than one car important objects of this invention will appear 3on atom, resides in the fact that under the as the description proceeds. Conditions of the Gattermann reaction the alkyl Para-alkyl benzaldehydes have been previously group Imigrates or is Split off completely. As a prepared by applying the Gattermann-Koch al iresult, most of the reactants are wasted in the 20 20 dehyde Synthesis to alkyl benzols. This synthesis production Cf di-and polyalkylated benzenes and may be considered aS 3. Special case of the Friedel di- and polyaikylated benzaldehydes with forma CraftS Synthesis, and consists of reacting to tion of large amounts of benzene. This splitting gether a suitabie ionolog of beinzene with car reaction is not prevented by the addition of bon inorioxide gas and dry hydrochloric acid in benzene as a diluent as has been suggested by 25 25 the presence of anhydrous aluminum chloride: Gattermann. It has also been known that benzene itself (that is, Without an alkyl Substituent) does not react under Similar conditions with carbon non (Annalen, 347, 347; 1906; Berichte, 30, 1622; 1897). 30 Oxide and hydrochloric acid to produce benzai 30 This reaction gives a good yieid (73%) of p-toluic dehyde. This fact was noted by Gattermann, aldehyde based on the quantity of toluene con Who States: Surned. It requires, however, a large excess of "The reaction is completely unsuccessful with CO gas, since Only about 30% of the CO gas ben Zoi under the influence of aluminum chlo 35 passed through the reaction mass combines with ride. This behavior is very desirable because 35 the toluene. it is thus possible to use benzol as a diluent with Moreover, in the case of the higher honologs Such hydrocarbons as are sensitive to alumi of benzene, the Situation is much less favorable. Although Gatternani Speaks of 'goods yields' num chloride.' (Annalen, 347, 347.) in conjunction With the aldehydes derived from I have now found that benzene may be very 40 40 ethyl-benzol and isopropyl-benzol, I have been readily and efficiently converted into cuminic unable to Substantiate these claims in my re aldehyde or any other optional para-alkyl benz searches. More particularly, f have ruin a series aldehyde, by Subjecting it simultaneously to the of experiments With this reaction as applied to action of Carbon monoxide, anhydrous aluminum 45 isopropyl-benzene, and followed very carefully chloride and isopropyl chloride or any agent 45 the directions given in the Cattermann re capable of introducing the desired alkyl group. action. The yield of Cunninic aldehyde (p-iso The choice of aikylating agent will of course propyl-benzaldehyde), however, was very low, be depend on the nature of the desired alkyl group ing about 4% of theory based on the quantity in para position to the aldehyde group, but aside 50 of isopropyl-benzene Consumed. On the other from this consideration may be any compound 50 hand over 50% of the isopropyl-benzene was re which is capable of introducing said alkyl group covered in the for in of benzene and of di- and into benzene under the influence of aluininum polyisopropyl-benzenes. By varying the condi chloride. Thus one may employ alkyl halides, tions of Gatternann, for instance, by working in alkyl alcohols, olefines, aikyl ethers, alkyl bo 55 a closed vessel at eXtremely high pressures (800 rates, or alkyl esters (formates, acetates). The 55 2 2,158,518 test is here whether or not a given COnpound is oil. Boiling point at 1.5 mm. Hg:110° C.; Refrac capable of condensing with benzene under the tive index n20:1.5490; melting point of Semi-car influence of aluminum chloride (that is, in the bazone: 215-217° C.; possessing an intense and absence of CO) to give an alkyl benzol of the lasting odor of the citrus type. desired type. If it is capable, it is Suitable for my novel reaction. EXAMPLE 7 Without limiting my invention to any particu USe Of an alcohol as alkylating agent lar procedure, the following examples are given Into a mixture of 480 parts of benzol, 320 partS to illustrate my preferred mode of operation. of AlCl3 and 32 parts of Cu2Cl2 are introduced O Parts mentioned are by Weight. simultaneously over six hours at ordinary tem O EXAMPLE 1. perature 42 parts of carbon monoxide, 27 parts of hydrogen chloride gas and 90 parts of iso 700 parts of benzol, 650 parts of aluminum propanol. The cuminic aldehyde formed may be chloride and 70 parts of cuprous chloride are isolated from the reaction product by means of 5 placed into a vessel provided with agitation. At 25-30° C. are gradually introduced during five its bisulphite compound. 5 hours, at ordinary pressure, 240 parts of isopro EXAMPLE 8 pyl chloride and, simultaneously 112 parts of car bon monoxide gas and 28 parts of dry hydrogen Use of an olefine as alkylating agent 20 chloride. The gases are bubbled through the re 28 parts of carbon monoxide gas, 42 parts of action mass and may be collected after paSSage propylene gas and 18 parts of hydrogen chloride 20 for reuse in a future operation. gas are simultaneously bubbled through a mix The reaction mass is poured on ice and Sepa ture of 400 parts of benzol, 270 parts of alumi rated into its components by suitable methods nun chloride and 25 parts of Cu2Cl2 at Ordinary or sightly elevated temperature. The resulting 25 Such as fractional distillation or fractional bi 25 Suiphitation. Besides unreacted benzol, there reaction mass contains a good yield of cuminic are obtained 115 parts of pure cuminic aldehyde, aldehyde. This may advantageously be isolated 40 parts of di-isopropyl benzaldehyde, 80 parts of in pure form by means of the bisulphite COm isopropyl benzol, and some di-isopropyl ben Zol. pound. 30 The recovered alkyl benzols may be reused in EXAMPLE 9 30 the next operation with the benzol, as is shown Use of an ether as alkylating agent in Example 2. EXAMPLE 2 Into a mixture of 800 parts of benzol, 650 parts Of Al{Cs and 60 parts of Cu2Cl2 are added Over 600 parts of benzol, 80 parts of isopropyl ben several hours simultaneously at 20-40° C. 120 Zol and 20 parts of poly-isopropyl benzols re parts of carbon monoxide and 204 parts of di-iso 35 covered in the preceding example are treated in propyl ether. Cuminic aldehyde in good yield the same manner as in Example 1, but using inay be isolated from the reaction maSS by frac only 160 parts of isopropyl chloride. The COm tional distillation or preferably by treatment position of the reaction product is similar to with sodium bisulphite solution. 40 Example i. The yield of cuminic aldehyde is It will be understood that my invention is not 40 about 110 parts, which corresponds to 35% of limited to the precise details given in the above theory from isopropyl chloride. examples, but may Wary Widely Within the Spirit EXAMPLE 3 of this invention. This, the reaction is oper ative at ordinary pressure fron 0° C. to the ten By feeding at ordinary temperature simulta perature of boiling benzol (78° C.); although for 45 neously carbon monoxide, hydrogen chloride gas best results, the range of 10° to 50° C. is pre and tertiary-butyl chloride, into a mixture of ferred. Under pressure, the temperature may be benzol, aluminum chloride and cuprous chloride, increased above 78° C. p-tertially-butyl-benzaldehyde is formed, which in the above examples, preSSures from 1 to 2 may be separated from the reaction mass by atmospheres, absolute, have been employed. 50 means of its bisulphite compound. In the pure There is, however, no limitation to the pressure state, it is a colorless oil; Boiling point at 3.5 employed except for the fact that at very high mn. Of Hg:91-92 C. pressures there may occur formation of benzalde EXAMPLE 4 5 5 hyde Siraultaneously With the formation of alkyl 5 5 From benzol, carbon monoxide and technical benzaldehyde. amyl chloride is obtained in a similar manner The relative quantities of reagents employed as described in Example 3, p-tertiary amyl benz innay vary within wide limits. To assure good aldehyde, characterized by the following con yields, tile amount of benzol should be at least 60 stants: Boiling point at 5 mm. Hg:122-124° C.; twice the theoretical amount (two mols benzol 60 Refractive index 1220:1.5270; melting point of for mol carbon fin Cinoxide), but it may be much semi-carbazone: 199-200 C.; odor: Spicy-sweet more or less. AS for the alkylating agent, best and Very lasting. yields are obtained if the Same and carbon mon oxide are used in about molecular proportions. EXAMPLE 5 65 If the amount of alkylating agent is increased, From cyclo-hexyl-chloride, carbon monoxide the main reaction product may be the corre and benzol is obtained, in a manner similar to sponding dialkyi benzaldehyde. Hydrochloric Example 3, p-cyclohexyl-benzaldehyde; Boiling acid gas may be used in Various ratios in rela point at 2.5 mm. Hg:126° C. tion to carbon monoxide or omitted entirely, es pecially When the alkylating agent contains oxy 70 EXAMPLE 6 gen or is a halide, because in these cases the From m-methyl-cyclohexyl-chloride, carbon alkylation produces dry hydrochloric acid gas monoxide and benzol is obtained, in an analogous Which Serves for the carboxylation with carbon manner, p - (m - methyl - Cyclohexyl) - benzalde monoxide. The amount of AlCl3 may vary great 75 hyde. In the pure State it is a colorless viscous. ly but for best yield it should be used in at least 75 2,158,518 3 one molecular proportion for each molecular pro 1. The process of preparing a para-mono-alkyl portion of carbon monoxide. benzaldehyde which comprises reacting upon The function of the cuprous chloride is cataly benzene with an alkylating agent in the presence tic. Its amount, therefore, may vary Widely, Say of aluminum chloride, and further reacting upon from 2 to 20% by Weight of the aluminum chlo the same reaction mass with carbon monoxide, ride. It may be replaced by other equivalent cat without isolating any intermediate compounds. alysts, for instance, cuprous bromide. 2. The process of preparing a para-mono-alkyl The preferred method of mixing the materials benzaldehyde, which comprises reacting upon consists of adding simultaneously the alkylating benzene simultaneously with carbon monoxide O agent and the carbon monoxide to a mixture and with an agent adapted to introduce an alkyl 0 of the benzol, aluminum chloride and catalyst. group, in the presence of aluminum chloride. However, it is possible to add the alkylating 3. The process of preparing a para-mono-alkyl agent first. benzaldehyde, which comprises reacting upon A number of modifications have been proposed benzene With carbon monoxide and hydrogen for the Gattermann aldehyde synthesis, all of chloride in the presence of aluminum chloride, 5 5 which may be used in connection with the pres While simultaneously feeding into the Same maSS ent process. For instance, nitro-benzol or Ortho a compound adapted to condense With benzene nitro-toluol may be added as Solvents. Iron under the influence of aluminum chloride to give chloride or titanium chloride may be present in an alkylated benzene. the AlCl3 or may be added to it. 4. The process of preparing a para-mono-alkyl 20 20 Among the alkylating agents, this invention is benzaldehyde, which comprises feeding simultane primarily concerned with Such as Will introduce ously into a mixture of benzene, aluminum chlo more than one carbon atom. ride and a Gatterman-Synthesis catalyst, gaseous The advantages of my invention Will now be carbon monoxide, dry hydrogen chloride, and an 25 readily understood. alkyl derivative adapted to act as an alkylating 25 By the novel method of this invention, it be agent under the influence of aluminum chloride. comes possible to extend the Scope of the Gatter 5. A process as in claim 4, the catalyst being a mann reaction for the introduction of carbon cuprous halide. monoxide into the benzol ring. The Gattermann 6. A process as in claim 4, the catalyst being 30 reaction has heretofore been used successfully cuprous chloride. 30 and commercially, only for such alkyl benzalde 7. A process as in claim 4, the quantity of hydes as possess side chains of one carbon atom. alkylating agent passed in being Substantially 1 By the novel process good yields of any alkyl mol for each 2 mols of benzene, whereby to avoid benzaldehydes may be obtained. formation of dialkylated benzaldehyde. 35 The Gattermann reaction starts from alkyl 8. A process of producing cuminic aldehyde, 35 benzols, which are expensive to prepare in all which comprises passing simultaneously into a cases where the alkyl group contains two or more mixture of benzene, aluminum chloride and carbon atoms. The novel process starts from the cuprous chloride, a stream of carbon monoxide inexpensive benzol and inexpensive alkylating gas, a stream of dry hydrogen chloride and an 40 40 agents, such as the alkyl chlorides or alcohols. isopropylating agent selected from the group As shown previously, the yields of p-alkylated consisting of isopropyl chloride, isopropyl alcohol, aldehydes are much superior with the novel di-isopropyl ether, and propylene. method for all cases where the alkyl group con 9. A process of producing cuminic aldehyde, tains three or more carbon atoms. Thus, not which comprises pasing simultaneously into a 45 45 only is the preparation of alkyl-benzol and alkyl mixture of benzene, aluminum chloride and benzaldehyde condensed into one step with elimi cuprous chloride, a stream of carbon monoxide nation of the isolation and purification of the gas, dry hydrogen chloride and isopropyl chlo alkyl benzol, but the yield of aldehyde is also ride. much improved, which constitutes a further in 10. A process of producing cuminic aldehyde portant economic advantage. which comprises passing simultaneously into a 50 My novel process has enabled me to Synthesize mixture of benzene, aluminum chloride and certain novel aldehydes. Thus, among the COm cuprous chloride, a stream of carbon monoxide pounds synthesized in the above examples the foll gas, dry hydrogen chloride and isopropyl alcohol. lowing appear to be novel compounds: p-tertiary 11. A process of producing cuminic aldehyde, 55 55 amyl benzaldehyde (Example 4) and p- (m- which comprises passing simultaneously into a methyl-cyclohexyl)-benzaldehyde (Example 6). mixture of benzene, aluminum chloride and These are useful as perfume materials due to cuprous chloride, a stream of carbon monoxide their original and lasting odors. gas, dry hydrogen chloride and di-isopropyl ether. I claim: WALTER CHRISTIAN MEULY.