US2609395A - Oxidation of hydrocarbons - Google Patents

Description

Sept 2, 1952 c. F. DouGHER-rY, JR., ETL 21,609,395

OXIDATION oF HYDRocARBoNs Filed vec. is, 1949 C. C. CHAP AN Y l m4 m ImZmDJOP A \ON lll ATTORNEYS Patented Sept. 2, 1952 OXIDATION OF HYDROCARBONS Charles Francis Dougherty, Jr., Bartlesville, Okla., and Charles C. Chapman, Phillips, Tex., assignors to Phillips Petroleum Company, a corporation of Delaware Application December 16, 1949, Serial No. 133,282

This invention relates to a process for partially oxidizing alicyclic hydrocarbons to produce corresponding alcohols and .ketones In one of its aspects it relates to a two-step process for oxidizing a cycloalkane With limited portions of an oxygen-containing medium and then treating the resulting oxidation effluent under controlled conditions of time, temperature, and pressure to selectively produce the corresponding cycloalkanol and cycloalkanone. In still another of its aspects this invention relates to a process for preferentially producing a secondary alkyl cyclohexanol to the substantial exclusion of the tertiary alkyl cyclohexanol by oxidizing a corresponding alkyl `cycloalkane under closely controlled reaction conditions in an oxidation zone and then treating the resulting oxidation product in a deperoxidization zone with an alkyl cycloalkane to produce the desired secondary alkyl cycloalkanol Without concomitantly producing substantial quantities of the tertiary alkyl cycloalkanol. In yet another of its aspects this invention relatesto a process for reacting a cycloalkane hydroperoxide with a cycloalkane to produce cycloalkanols as well as cycloalkanones.l In yet still another of its aspects, this invention relates to a process for oxidizing a cycloalkane with limited quantities of an oxygen-containing medium and under closely controlled reaction conditions to produce principally a cycloalkane hydroperoxide. In still yet another of its aspects, this invention relates to a process for separating an aromatic hydrocarbon from admixture withv an alicyclic hydrocarbon by oxidizing said alicyclic hydrocarbon with limited quantities of an oxygen containing medium and then separating said aromatic hydrocarbon from the resulting effluent.

The oxidation of various hydrocarbons to alcohols, ketones and the like has long been known and practiced in the prior art. Itis also known in the prior art to oxidize unsubstituted cycloalkanes. In such processes it isknown that in addition to the alcohols and ketones thereby. produced, considerable quantities of tars and kpolymers are likewise produced as undesirable ley-products. It is known that these tars and polymers are decomposition `and degradationproducts of cycloalkane hydroperoxides `which' are formed while oxidizing thecycloalkane, "It

is further known that cycloalkane hydroperoxides are unstable in nature and if concentrated to any large extent that they are highly explosive and therefore dangerous to handle. Hence it has been an object of the prior art to minimize the production of these hydroperoxides and t I7 Claims. (Cl. 260-586) have been oxidized to produce principally tertiary alkyl cycloalkanols and acyclic ketones. As is obvious to one skilled in the art, a tertiary alcohol, such as tertiary alkyl cycloalkanol, is a less desirable compound than the corresponding secondary alkyl cycloalkanols because the tertiary alcohols in general, and the tertiary alkyl cycloalkanols in particular, are diicult to convert to esters which is one of the principal applications of the alkyl cycloalkanol compounds.r rIt is also well known in the prior art to oxidize the various alkyl cycloalkanes to produce acyclic ketones but in such processes the production of the alkyl cycloalkanones is not accomplished. The alkyl cycloalkanones are widely used as specialty solvents in many industrial processes where the acyclic ketones are not applicable. As stated, the oxidation of cycloalkanes results in --the production of considerable amounts of cycloalkane hydroperoxides and it would be highly advantageous to provide a process for not only avoiding dangerously explosive concentrations'of these hydroperoxides but to also convert these hydroperoxides into a desired and useful product instead of 'to tars and polymers. Also, as stated,

secondary alkyl ,cycloalkanols are `Widely used and therefore it vwould be advantageous to provide an oxidation process for producing predominantly secondary alkyl cyclohexanols and alkyl cyclohexanones from al readily available starting materialwithout substantial production of the tertiary alkyl cycloalkanols and Without incurring thedisadvantages of the prior art processes such as the Vformation of excessive amounts of undesirable tars and the danger of exploding the concomitantly formed hydroperoxides.v Such a process was not known to the present inventors prior to the making of the instant invention.

Still further in the prior art, it is known that admixtures of certain alicyclic hydrocarbons, such as methylcyclohexanes, and certain aromatic hydrocarbons, such as toluene, are very diicult to separate by aY fractional distillation process. It is theusual practice to employ sev- -eral fractional distillation steps involving heartcutting operations with the resultant disadvan- V,tage that onlya small percentage of the orign alkanoland cycloalkanone without concomit'antly.

producing any substantial quantities of polymers Step II:

3 or tars and Without incurring the danger of explosive concentrations of an intermediately produced cycloalkane hydroperoxide and that a cycloalkane hydroperoxide produced during the oxidation of a cycloalkane can be further converted to a desirable -cycloalkanol and cycloalkanone by oxidizing, the cycloalkane in a lrst Zone with limited quantities of an oxygen-containing medium and then in the substantial absence of any free oxygen, reacting said hydroperoxide with a cycloalkane in a second zone maintained under carefully controlled reaction conditions. It has also been found that a cycloalkane can be oxidized With limited quantities of oxygen from an oxygen-containing medium under controlled reaction conditions to produce a cycloalkane hydroperoxide as the principal product, Furthermore, it has been found that an alkyl cycloalkane can be oxidized to secondary alkyl cycloalkanol to the substantial exclusion of the tertiary alkyl cycloalkanol in a two-step process comprising an Oxidation step wherein an alkyl cycloalkane is reacted with limited quantities of oxygen to .produce predominately an alkyl cycloalkane hydroperoxide and a deperoxidization step wherein the alkyl cycloalkane hydroperoxide thus produced is deperoxidized by reaction with an alkyl cycloalkane to produce the desired product Without concomitantly producing undesirable tars and Without incurring the risk of dangerous explosions of the hydroperoxide. Still further, it has been found that 'an aromatic hydrocarbon can be readily separated from an admixture with a cycloalkane by first oxidizing Athe mixture With limited quantities of an oxygen-containing medium and separating the unreacted cycloalkane and the aromatic hydrocarbon from the oxidation eilluent. The aromatic hydrocarbon, under the oxidation conditie-ns employed, is not oxidized and therefore passes through the oxidation process unchanged. The oxidation effluent has been found to bereadily fractionatable into a substantially pure cycloalkane stream and an oxidate stream which contains the unoxidized aromatic hydrocarbon. The latter stream can then be easily separated into an aromatic hydrocarbon fraction and an oxygenated hydrocarbon fraction. Thus, the presence of the. small amount of oxygenated cycloalkane permits an easy separation of the ordinarily diiicultly separable cycloalkanearomatic hydrocarbonadmixture into cycloalkan and aromatic hydrocarbon fractions. Thus, a cycloalkane isoxidized to a limited ex- Hence it is apparent that the process of this invention provides ameans for producinga cycloalkanol and cycloalkanone without producing undesirable tars and polymers inherently produced in the prior art processes. lt is also apparent that when an alkyl cycloalkane is oxidized the principal product is a desirable secondary alkyl cycloalkanol and alkyl cycloalkanone and not the less desirable tertiary alkyl cycloalkanol. itis further apparent that theprocess of this invention does not seek to avoid the production of hydroperoxides but, on the contrary, is speciiically directed to their production in order that they can be converted` intol the desired cycloalkanol and cycloalkanone using additional quantities of i cycloalkane, as described herein. it is also apparent that When a cycloalkane-aromatic hydrocarbon adrnixture is desired to be separated into its ,.components, theprocess of this invention pro- Vides an easy method forrso doing without retent in an oxidation zone by limited amounts of oxygen to form principally a cycloalkane hydroperoxide. cycloalkane is then passed to a deperoxidization zone whereinv the cycloalkane hydroperoxide is deperoxidized in the substantial absence of any free oxygen and under carefully controlled'reaction conditions by reactionwith a cycloalkane to produce a cycloalkanol and a cycloalkanone. Thus the following equations can be used to demonstrate the process of this invention:

Stepl:y 1 I R-i- 0. n'ocir wherein R is a'cycloalkane hydrocarbon,andiR"t is A mixture of such hydroperoxide and sorting to extended fractionation procedures and Without incurring the disadvantage of. recovering only a small' percentage of the original cycloalkane component in the cycloalkane-aromatic hydrocarbon adrnixture.

In order to more fully set forth and to describe this invention, it will be described with particular reference tothe attached drawing which illustrates one of the embodiments of the process of this invention and with reference to a. spec-inc reaction, namely the oxidation of methylcyclohexane to produce predominantly l3- methyicyclohexanol and `lesser quantitit-:sv of methylcyclohexanone to the substantial exclusion of l-methylcyclohexanol. However, it is to be understood that cycloalkanes other thanV inethyl'cyclohexane can be readily employed in the `processi of this invention to realize the advantages thereof. Thus this invention contemplates oxidizing not only inethylcyclohexane but also other` cycloalkanes containing from` 5 to.. 8 carbon iatoms in the cyclic ring as well as the alkylated derivatives thereof. Thus cyclopentane, cyclohexane, cycloheptane, cyclo-octane, ctc., as

well asl the various monoand dialkyl cycloalkanes such as the methyl", dimethyl, ethyl, propyl, butyl, etc., substituted products of the abovementioned 'cycloalkanes'. n f Y Inthe drawing, a methylcyclohexanejfeed is passed through line I to'reactor 2. The methylcyclohexane feed preferably contains minor portions of other -hydrocarbon constituents such" as cycloalkanes Vother lthan methylcyclohexane. Some straight-chain'parainns having a-boili'ng point near that 'ofV methylcyclohexane vcan also be-used as a feedstock component.v Itvhas been found thatwhen methylcyclohexane contains minor portions ofthese hydrocarbon impurities, it is oxidized at a faster ratethan pure methylcyclohexane. These impurities may be partially oxidized in reactor 2 but their oxidized products are readily separated by fractio'rfialf.distillationv from the principal products, methylcyclohexanolsand methylcyclohexanones.' Under some circumstances, Where -the vinethylcyclohexa'ne feed is very pure, it is advantageous-to add suihcient amounts-of the above-mentioned impurities to the pure feed in order to maintain a high oxidation rate of the methylcyclohexane feed. An oxygen-containing medium such as air, is passed through line 3 into -reactor 2 -wherein itis intimately admixedrwith the methylcyclohexane feed by means of mechanical stirrers; jet mixers, or the like. It is important to produce avery intimate admixture of the oxygen and hydrocarbons in reactor 2 in order to ensure complete reaction of the oxygen with the hydrocarbons Without excessive oxidation ofthe hydrocarbons-to undesirable products, such as organic acids. The oxygen-containing medium is fed into the oxidation reactor at a rate Vsuiiicient to supplythe oxygen necessary to eifectthe desiredconversion of the methylcyelohexane to a corresponding hydroperoxide.'v The amountof oxygen employed per VolumeV of methylcyclohexane feed ushould be limited' to an amount Suchthatthe oxygenated products comprise principally a methylcyclohexane Ihydro'- peroxide.' The exact amountof oxygen used'depends on anumber of lfactors such as the-desired degree lof. conversion of the `methylyclohexane feed, Ythe vrtemperatuie and residence time of the.

reactants in reactor 2, etc( In` any event, the-exact `amount of oxygen can be determined by mere routine test and is preferably Within the range of about 0.05' to about 0.2 mol, more preferably "about/0.10am about-0.15 mol of oxygenper mol of methylcyclohexane feed. The 'temperature in oxidation reactor 2 is maintained yat such a level thatthe formation of a methylcyclohexane hydroperoxide is effected Without substantial decomposition thereof Yinto. undesirable products such as tars, polymers, and organic acids. Temperatures in a range of about 150 to about 210 C., preferably from about .155:t'o about 180"C. are employed. Thevpressure in the reactor 2 is sufficient to maintain the reactants in a liquid state'andS-islfrom 'about 50 to about 1000'pounds per square inch gage, preferably from about 100 to about 500y pounds per-square inch-1v gage. -The residencetirne of the reactants in're'actor 2 is adjusted Yto permit substantially complete consumption of the-oxygen'added to thehydroc'arstantially no free oxygen. Thatis, longer reaction' times are'required for'loW reaction tempera- 6. tures than for high reaction temperatures. And, at any given temperature, longer reaction times' are required for large amounts of added oxygen than for small amounts; When the above-speci' fied ranges of oxygen concentrations and reaction temperatures are employed, the 'residence time isL from about50'- minutes to about 3 minutes, .preffluent. A hydrocarbon insoluble. phase containing 'organic acids can be'withdrawn from separator 5 via 1ine21 and discarded. The oxidation reactor hydrocarbon soluble effluent yis then passed through line 1 and heat exchanger 8 to deperoxidization reactor 9. As will be explained hereafter, the temperature of the deperoxidizaa tion reactor 9 can be maintained higher or lower than that of oxidationreactor 2 and hence, heatv exchanger- 8 is employed to add heat or to cool the feed to the reactor. The oxidation reactor eiliuent passing through linev 'I will ordinarily contain substantially no free oxygen since the conditions in reactor 24 have been regulated to effect its substantial consumption. However,Y if a minor amount of oxygen is contained in the eflluent from reactor 2, it is removed therefrom in gas separator 5 to thereby furnish an oxygenfree charge -to deperoxidization reactor 9 Whereby any ketones formed in deperoxidization reactor 9 will not be further oxidized to the less desirable acids. The charge to reactorv 9 then comprises principally a .major portion .offunrea'cted methylcyclohexane and aIlesserfouantity of the intermediate methylcyclohexane lhydroperoxide and'alsc varying quantities; of Z-heptanone.' I

Itf has .been found that when a methylcyclohexane vhydroperoxide containing oxidation reaction.'e1iiuent is fractionated at v10W temperatures,

say. atabout C., tore'cover oxidized prodfucts, then the hydroperoxides decompose 'sub-- Stantially :completely :to polymers, tars,Vv etc.,l which are'not only of no commercial valuelbutl also tend to coat and cokify vany 'equipment in' which they arehandled. It YisI also noteworthy that when these;'hydroperoxide-containingl oxidation eiliuents .are 4fractionated-to recover other oxidized products, theliydroperoxides .will concentrate 1in one fraction and, 'sinceqthey areV chemically. unstable `in nature', there is-a-de-l nite risk of Van explosionxoccurring.fnsfstated;

formed inthe 'oxidation reactortolthedesired secondary ,methylcyclohexanols and methylcyfcloihexanones Without substantial decoinposition'--ofl the hydroperoxide 'into undesirable products such 3S. polymers, tars, etc. and Withoutfdange'r 'of` hydroperoxide. When. a, methylcyclohexane hydroperoxide" *is treated underecomparatively severe-freaetionfooncurious with' an' excess' of methylcyclohexane, the;

hydfopefid.e Willlgbe* Converted. 5 substiliiklire quantitatively to the desired secondaryalcoholsj andketones by rreaction ywith afportion"".f'theJ it is about t0 1.

methylcyclohexane; The mode of accomplishing this desirableV conversion is by utilizing a long reaction time and/ or high reaction temperatures in"thet-deperoxidization reactor 9- and by maintaining methylcyclohexanein a substantial excess over that required to reactwith the hydroperoxide'in order to maintain thef latter in a dilute *state `therebypreventing any violent reactions or explosions. It is readily apparent that the reaction conditions in deperoxidization reactor 9l must be closely controlled' to prevent the hydroperoxide decomposing to' form tars, etc. and since any high concentrations of hydroperoxide in reactorV 9 are'apt to result in anl explosion'. i Asa general rule, lwe have found that the reaction. temperature 'in deperoxidization zreactor 9"tends`to be from about 5 to aboutl 50 C. higher than the temperaturein oxidation reactor 2.` The' increaseY in temperature isk due at least in part to the exotlierm'icity' of 'the reaction in the'deperoxidization reactor 9. However, it is not essential' to this invention that the deperoxidization zone operate ata higher temperature than the oxidization zone and hence, the temperatures in the deperoxidization reactor 9 can 'range' from about 160 to about 260 C., preferably from about' 175' to about 205 C'. The choice of the exact operating temperature will depend upon the residence time of theu liquid in reactorY Il a's will be more fully explained hereafter. The pressure in reactor 9 shouldbe maintained ata level high enoughto permit liquid phase conditions to obtain'therein. Generally the-pressure can range from about 50 to about 1000 poundsl per square inch gage, preferably from aboutv 100 to about 500 pounds per square inch gage. As stated, the reactionV temperature maintained in reactor 9-will depend upon the liquid residence time of the reactants in reactor 9. When employing the ranges ofA temperature specified above, it has been found that the liquid residence time can range fromabout 200 VtoA about l0 minutes,` preferably fromlabout 60 to about minutes. so adjusted and so correlated with the reaction tempera-ture that theV methylcyclohexane hydroperoxide is all substantially converted tothe desiredv methylcyclohexanols and methylcyclohexanones. Thus, longer reaction times are required for low reaction temperatures than for high reaction temperatures. At any given temperature the optimum residence time can be determined by mere routine test.

The ratio of methylcyclohexane to methylcyclohexane hydroperoxide is regulated to maintain a dilute solution ofthe latter in the former in order to prevent explosive concentrations of the hydroperoxides from accumulating and to ensure -substantially complete conversion of the hydroperoxides to secondary alcohols andY ketones' instead of to tars;polymers,A etc. Generally thevk mol ratio of methylcyclohexane to methylcyclohexane hydroperoxide can range from about 30 to 1 to about 5 to l and preferably Within theseV ranges, there is substantially no likelihood of an explosion and the conversion ofthe hydroperoxides is substantially quantitative. In the ordinary operation of the process of this invention, the` unreacted methylcyclohexane accompanying the oxidized products from oxidation reactorf2 -willbe suf-Y ficient to maintain the above diluent ratios. However, in-those cases wherein the methylcyclo- The residence time should'be4 the eiiiuent products from said zone is insuicient to maintain the desired diluent ratios, additional methylcyolohexane can be added from an outside:

source through line 26 or some recycle methylcyelohexane from line I5 can be diverted through line-25 toline 1. Upon completion of the deperoxidi-zation reaction in reactor 9, .the deperoxi-` dization reactoreflluent is passed through line I0 to Van acid neutralization zone I I wherein minorn dation reactor 2.- In some instances the returning methylcyclohexane in line I5 contains considerable water-formed in lprevious processing steps, especially in the neutralization step.- In suchy cases itis desirable to separate the-water from the returning methylcyclohexane by passing it through separator I6. Separator I6 can be of any suitable type such as filter, bauxite dryer, etc. In addition, as above noted, it is advantageous in our process to employ methylcyclohexane feedl which contains -minor portions of other cycloalkanes and/or straight chain parans to promote the 4oxidation reaction. Hence if the returning methylcyclohexane in line IIE contains insufiicient amounts of these impurities, additional amounts are added through line I'I. Y

The residual product from fractionator I4 passes through line I8 to toluene separator I9. The inclusion of toluene separator I9 in Vthis process is highly desirable when the original methylcyclohexane feedstock contains appreciable quantities of toluene which is very difiicult to-separate-prior to the oxidation of the feedstock `butis unexpectedly easy to separate after the oxidation and deperoxidization steps.

Y Thus it is possible to remove a toluene concentrate from .fractional distillation column` I9.k

through line 20.- Tolueneis-substantially unreactive inthe oxidation process and therefore there is no, advantage in recycling this material to the process. The toluene-free product comprising substantially oxygenated hydrocarbons is passed through line 2I to fractionator 22./ In fractionator 2'2Y the desired secondary methylcyclohexanolsand methylcyclohexanones are removed overhead through line 23, and other heavier oxygenatedv hydrocarbon byproducts can be removed through line 24. If desired, further separation between'theV methylcyclohexanols and methylcyclohexanones and/or the respective isomers thereof can be accomplished through processes not ,forming a part of this invention. l

The following examples will serve to illustrate the process of this invention:

Methylcyclohexane of' 85 per .cent purity was pumped yinto-a turbine-stirred oxidation reactor at arate-sufficient to maintain a total residence. time of the liquid phase in the reactor at 7 min--I utes. -Compressed air,` was fed into the reactor at a rate suilicient to supply 0.11 mol oxygen perrnol methylcyclolfiexane.` The oxidation reactor was T maintained at ITI-174 C. and at 500 p. s. i. g.

and after 50 minutes the oxygen content of the spent gases Was found to be between 0.0-0.2 per cent and a steady state had vlbeen reached with respect to reactant and product concentrations; The concentration ofmethylcyclohexane hydro-.

yperoxides inthe oxidationreactor eliuent was then'2.5 mol per cent. After separation of offgases and a hydrocarbon insoluble liquid phase, hot eilluent stream. was carried to a deperoxidization reactor, the exothermic heat generated in said reactor being suiicient to maintain the temperature therein at 177 C. lThe residence time ofA the liquidwithin this reactor. was 60 minutes and the pressurev employed was 200 pounds per square inch gage. The deperoxidized eliiuent contained less than 0.005 mol per cent peroxides calculated as methylcyclohexane hydroperoxide in methylcyclohexane. The eiliuent was cooled and all liquid phases thereof were combined and treated With sufcient potassium carbonate to neutralize the acids present. The solution of neutral products in unreacted hydrocarbon was fractionally distilled, first at 200 mm. of Hg pressure to remove the unreacted hydrocarbon and then at 90 mm. of V-Hg pressure to recover the volatile alcohols and ketones .as overhead fractions.

'Ihe ultimate yield of volatile alcohol and ketone products based on the methylcyclohexane consumed in the process was 7 4 mol per cent. The products Were comprised of 31 per cent B-methylcyclohexanol, 29 `per cent methylcyclohexanones, 25 per cent 2-hepta-none, 13 per cent 2- and 4- methylcyclohexanols" and 2 per cent l-.methylcyclohexanol. A 1

I Example II The above conversion was repeated under identical conditions lexcept that the deperoxidization reaction was omitted. The distillation Was carethe ketone content of the product was somewhat less. An kalmost two-fold increase Ain tars over 'that of Example I'was observed.

Methylcyclohexane of '85 .per cent purity was oxidized at 120"` C.and at 500 pounds per square inch gage pressure. The'v residence time of the liquidphase inthe oxidationv reactor was maintained at 180 minutes. .The oxygen consumed during the oxidation reaction'was'Oll mol per mol methylcyclohexane. The oxidized eluent stream contained 3.8 mol per cent methylcyclohexane hydroperoxides. The deperoxidization reactionwas notv 'employed'and theA oxidation eiiluent was Vneutralized and distilled very carefully to vavoid an explosion. i u

lThe ultimate yield of volatile alcohols and ketones based on the methylcyclohexane consumed in the process 'was 64v mol percent. The products were comprised of`65^per cent l-methylcyclohexanol, .2`5f per centA Z-heptanone; and' only loper cent methylcyclohe'xanones and secondary ,methylcyclohex'anols.'A 'Ilie productivity of the oxidation reactor,'based on gallons of lvolatile alcoholsY and ketones'profduced per gallon of oxidation reactor spacev in one day was 3.3 per cent of that obtained in Example I.

Methylcyclohexane oi 85 per cent purity was -oxidized as in'Exarnple I [except that the deperoxidization reactor was j'maintained at 205 C. instead of 177 C;;and the total residence time of the liquid phase in said reactor was 20 instead of 60v minutes.` The yield ofvolatile alcohols and Yketones based on the methylcyclohexane consumed in the process was substantiallythe Example vV Methylcylohexane or vv per centpurity Was pumped into a turbine-stirred oxidation reactor at a rate suiiicient tomaintain the residence time of the liquid phase in the reactor at 50 minutes. Compressed air Was fred into thereactor at such a rate as to supply 0.11 mol of oxygen per mol methylcyclohexane. The oxidationreactor was maintained 'at155 and at 500 pounds per square inch gage.` .The oxidation elue'nt which contained 3.5 mol per cent methylcyclohexane hydroperoxides, was passed through a preheater where heat from Athe deperoxidization reactor effluent Wasutilized to bring the oxidation reactor effluent stream to 175 C. The stream was then passed throughan auxiliary heat exchanger Where its temperature was raised to C. The exothermic heat generated in' the deperoxidization reactor wassui'cient to bring the temperaturcof the reactants in this reactor to 205 C. The residence time in the deperoxidizing reactor was 20 minutes which was suiciently long to permit reduction of the peroxides in the eilluent productsto below 0.005 mol per cent based on methylcyclchexane hydroperoxide in methylcyclohexane. "The crude deperoxidizedi'product Was purified as in Example I. The ultimate yield of volatile alcohols and ketones was 80 mol per cent based'jon, the methylcyclohexane consumed in the process and thejdistribution of oxidation products vlas similarto' that obtained in Example -'I.- I-IoW- ever,` lthe productivity based-on the volume of oxidation yreactcir'space Was only 15 per cent of that obtained in Example I.= f

In accordance with this invention a cycloalkanevcan be oxidized to: produce cycloalkanols and cycloalkanones in ra two-stepl process comprising an oxidation stepjwhereina cycloalkane is reacted withlimited quantities of oxygen and a deperoxidizati'on `step wherein the cycloalkane hydroperoxides produced in' said rst mentioned stf'a'pa're dep'eroxidized by reaction with a cycloalka'ne toproduce, the' desired product Without concomitantly producing undesirable tars and without incurring the risk of dangerous explosions 'of the 'sai'dvhydroperoxidea saidsecond step of the deperoxidization of the ysaidfhydroper- .oxides being consideredL an important and highly advantageous step forward in art and further, thatv` any l'aromatic hydrocarbons present in the cyclalkane' feedstock can beH readily separated :therefrom by aj simplefractional distillation of the oxidized elilujent fromsaidoxidation reaction While theinvention has been described in connection with a'fpre'sent, preferred embodiment thereof, itis to .be understood thatthis description yis illustrative only `and is not intended to limit the invention, the scope of which is dened by the appended claims. v Y .'We claim: .Y i; 1. A processv for producing 3-methylcyc1ohexa` nol to the substantial exclusion of l-methylcyclohexanol which comprises passing methylcyclohexane hydroperoxide to a deperoxidization zone, maintaining an excess of methylcyclohexane in said zone whereby the said hydroperoxide is reacted with a portion of said excess methylcyclohexane, maintaining said zone at a temperature of about 16 to about 260 C. and under a pressure of about 50 to about 1000 pounds per square inch, adjusting the rate of flow of total feed to said zone to be such that the residence time of said feed in said zone is about 200 to about minutes whereby the methylcyclohexane hydroperoxide is substantially converted to the desired product without any substantial production of tars and without incurring the risk of explosive concentrations of said hydroperoxide.

2. A process for producing 3-methylcyclohexanol to the substantial exclusion of 1-methylcyclohexanol which comprises passing methylcyclohexane hydroperoxide to a deperoxidization zone, Y

maintaining a substantial excess of methylcyclohexane in said zone whereby the said hydroperoxide is reacted with a portion of said excess methylcyclohexane, maintaining said zone at a temperature of about 175 to about 205 C. and under a pressure of about 100 to about 500 pounds per square inch, adjusting the rate of flow of total feed to said zone to be such that the residence time of said feed in said' zone is about 60 to about 20. minutes whereby the methylcyclohexane hydroperoxide is substantially converted to the desired product without any substantial production of tars and without incurring the risk of explosive concentrations of said hydroperoxide.Y

3. A process for producing a cycloalkanol and a cycloalkanone which comprises reacting a cycloalkane hydroperoxide with a 'stoichiometric excess of a cycloalkane at a temperature in the range 160 to 260 C., a pressure in the range 50 to 1000 p. s. i., and a reaction time in the range 10 to 200 minutes, and recovering a cycloalkanol and a cycloalkanone as products "of the process el. The process of claim 3 wherein the cycloalkane hydroperoxide vis an `alkyl cycloalkane hydroperoxide and the cycloalkane is an alkyl cycloalkane whereby a secondary alkyl cycloalkanol is preferentially produced with respect to tertiary alkyl cycloalkanol.

5. The process of claim 3 wherein the cycloalkane-hydroperoxide is cyclohexane hydroperoxide` and the cycloalkane is cyclohexane.

6. The process of claim 3 wherein the cycloalkane hydroperoxide is methylcyclohexane hydroperoxide and the cycloalkane is methylcyclohexane whereby B-methylcyclohexanol is preferential'ly produced with respect to l-methylcyolohexanol.

'7. A two-step process for producing principally 3methylcyclohexanol and lesser amounts of 2- and 4.methylcyclohexanol and 2,-, 3- and 4 meth ylcyclohexanone to the substantial exclusion of l-methylcyclohexanol which comprises oxidizing methylcyclohexane feed in the presence of minor portions of cycloalkanes other than methylcyclohexane in an oxidation zone with air added to said zone at a rate equivalent to about one-tenth mol of oxygen per mol of methylcyclohexane feed, maintaining said oxidation zone at a temperature of 171 to 174C. andA under a pressure of about 500 pounds per square inch gage, adjusting the rate of flow of hydrocarbon feed to said oxidation zone to be such that 'the residence time of said feed in said oxidation zone is. about '7 minutes whereby the efuent products from said zone are substantially free of unreacted oxygen;

passing said effluent products from` said oxidation zone to a deperoxidization zone, maintaining a substantial excess of unreacted methylcyclohexane in said deperoxidization zonewhereby a methylcyclohexane hydroperoxide produced in said oxidation zone is reacted with a portion of said excess methylcyclohexane, maintaining said deperoxidization zone at a temperature of 177 C. and'under a pressure of 200 pounds per square inch, adjusting the rate of flow of feed to said deperoxidization zone to be such that the residence time of said feed in said zone is about 60 minutes whereby the methylcyclohexane hydroperoxide is substantially converted to the desired products without any substantial concomitant production of tars and without incurring any risk of explosive concentrations of said hydroperoxide.

8. A two-step process for producing principally B-methylcyclohexanol and lesser amounts of 2- and 4-methylcyclohexanols and 2-, 3- and 4- methylcyclohexanones to the substantial exclusion of l-methylcyclohexanol which comprises oxidizing methylcyclohexane feed in the presence of minor portions cycloalkanes other than methyloyclohexane in an oxidation zone with air added to said zone at a rate equivalent to about 0.1 to about 0.15 mol oxygen per mol of methylcyclohexane feed, maintaining said oxidation zone at a temperature of about to about 180 C. and under a pressure of about 50 to about 1000 pounds per square inch gage, adjusting the rate of flow of hydrocarbon feed to said oxidation zone to be such that the residence time of said feed in said oxidation zone is about 15 to about 5 minutes whereby the effluent products from said zone are substantially free of `unreacted. oxygen; passing said eliiuent products from said oxidation zone to a deperoxidization zone, maintaining a substantial excess of unreacted methylcyclohexane in said deperoxidization zone whereby a methylcyclohexane hydroperoxide produced in said oxidation zone is reacted` with a portion of said excess methylcyclohexane, maintaining said deperoxidization zone at a temperature of about to about 205 C. and under a pressure of about 100 to about 50,0 pounds per square inch, adjusting .the rate of flow of feed to said deperoxidization zone to be such that the residence time of said feed in said zone is about 60 to about 20 minutes whereby the methylcyclohexane hydroperoxide is substantially converted to the desired product without any substantial concomitant production of tarsV and without incurring any risk of explosive concentrations of said hydroperoxide. 9. A two-step process for producing principally 3-methyloyclohexanol to the substantial exclusion of v1methylcyclohexanol which comprises oxidizing methylcyclohexane feed in an oxidation zone with an oxygen-containing medium added to said zone at a rate equivalent to about 0.05 to about 0.2 mol oxygen per mol of methylcyclohexane feed,y maintaining said oxidation zone at a temperature of about 150 to about 210 C. and under a pressure sufcient to maintain liquid phase conditions in said oxidation reactor, advju'sting the rate of flow of hydrocarbonv feed to `said oxidation zone to be such that the residence time of said feed in said oxidation zone is about 50 to about 3 minutes whereby the liquid effluent products from said zone are substantially free of unreacted oxygen; passing all of said efuent liquid products from said oxidation zone to a deperoxidization zone whereby a methylcyclohexane hydroperoxide produced in said. oxidation zone is reacted with a portion of the unreacted methylcyclohexane from said oxidation zone, maintaining said deperoxidization zone at a temperature of about 160 to about 260 C. and under a pressure sufficient to maintain liquid phase conditions in said deperoxidization zone, adjusting the rate of flow of feed to said deperoxidization zone to be such that the residence time of said feed in said zone is about 200 to about y minutes whereby the methylcyclohexane hydroperoxide is substantially converted to the desired product without any substantial production of tars and without incurring the risk of explosive concentrations of said hydroperoxide.

10. A process for producing a cycloalkanol which comprises partially oxidizing a cycloalkane in an oxidation zone with an oxygen-containing gas added to said oxidation zone at a rate in the range 0.05 to 0.2- mole of oxygen per mole of cycloalkane, maintaining said oxidation Azone at a temperature in the range 150 to 210 C. and a pressure sufficient to maintain said cycloalkane substantially in the liquid phase, maintaining a residence time of cycloalkane in said oxidation zone in the range 3 to 50 minutes; passing eiiiuent products containing a cycloalkane hydroperoxide and a stoichiometric excess of unreacted cycloalkane from said oxidation zone to a deperoxidi-v zation zone, maintaining said deperoxidization zone at a temperature in the range 160 to 260 C. and a pressure in the range 50 to 1000 p. s. i., maintaining a residence time of said eiiiuent products in said deperoxidization zone in the range 10 to 200 minutes, and recovering a cycloalkanol as a product of the process.

11. 'I'he process of claim 10 wherein the cycloalkane is an alkyl cycloalkane whereby a secondary alkyl cycloalkanol is preferentially produced with respect to tertiary alkyl cycloalkanol.

12. The process of claim 10 wherein the cycloalkane is methylcyclohexane whereby 3-methylcyclohexanol is preferentially produced with respect to 1-methylcyclohexanol.

13. The process of claim 10 wherein the cycloalkane is cyclohexane.

14. A process for producing methylcyclohexane hydroperoxide which comprises oxidizing a methylcyclohexane feed in the presence of minor portions of cycloalkanes other than methylcyclohexane in an oxidation zone with air added to said zone at a rate equivalent to about one-tenth mol oxygen per mol of methylcyclohexane feed, maintaining said oxidation zone at a temperature of 170 to 174 C. and under a pressure of about 500 pounds per square inch gage, adjusting the rate of flow of hydrocarbon feed to said oxidation zone to be such that the residence time of said feed in said zone is about 7 minutes whereby the desired hydroperoxide is produced.

15. A process for producing methylcyclohexane hydroperoxide which comprises oxidizing a methylcyclohexane feed in an oxidation zone with an oxygen-containing medium added to said zone at a rate equivalent to about 0.05 to about 0.2 mol oxygen per mol of methylcyclohexane feed,

maintaining said oxidation zone at a temperature of to about 210 C. and under a pressure sufficient to maintain liquid phase conditions in said zone adjusting the rate of flow of hydrocarbon feed to said oxidation zone to be such that the residence time of said feed in said zone is about 50 to about 3 minutes whereby the desired hydroperoxide is produced.

16. A process for concomitantly producing a secondary cycloalkanol and cycloalkanone and separating an aromatic hydrocarbon from a cycloalkane hydrocarbon which comprises passing a feedstock comprising a mixture of said aromatic and said cycloalkane hydrocarbons to an oxidation zone, oxidizing said feedstock with air added to said zone at a, rate equivalent to 0.05 to 0.2 mol oxygen per mol of cycloalkane in said feedstock, maintaining said oxidation zone at a temperature between 150 and 210 C. and under a.

pressure sufficient to maintain liquid phase conditions in said oxidation reactor, adjusting the rate of flow of hydrocarbon feedstock to said oxidation zone to be such that the residence time of said feedstock in said oxidation zone is from 50 to 3 minutes whereby the liquid effluent products from said zone are free of unreacted oxygen; passing said eiiuent liquid products from said oxidation zone to a deperoxidization zone wherein a cycloalkane hydroperoxide produced in said oxidation zone is reacted with a stoichiometric excess of unreacted cycloalkane from said oxidation zone, maintaining said deperoxidization zone at a temperature between 160 and 260 C. and under a pressure sufcient to maintain liquid phase conditions in said deperoxidization zone, adjusting the rate of flow of feed to said deperoxidization zone to be such that the residence time of `said feed in said zone is 200 to 10 minutes; passing the resulting oxidized and deperoxidized eiuent from said deperoxidization zone to a fractional distillation zone, removing substantially pure cycloalkane, said aromatic hydrocarbon and the oxygenated products as separate products of the process.

17. The process of claim 16 wherein the said cycloalkane is methylcyclohexane and the said aromatic hydrocarbon is toluene.

CHARLES FRANCIS DOUGHERTY, JR. CHARLES C. CHAPMAN.

REFERENCES CITED The following references are ofY record in the le of this patent:

UNITED STATES PATENTS Number Name Date 2,223,494 Loder Dec. 3, 1940 2,410,642 Farkas et al Nov. 5, 1946 2,475,605 Prutton et al July 12, 1949 2,497,349 Farkas et a1. Feb. 14, 1950 OTHER REFERENCES Frank, Chemical Reviews, Vol. 46, Feb., 1950, pages -169.

Claims (2)

1. 3. A PROCESS FOR PRODUCING A CYCLOALKANOL AND A CYCLOALKANONE WHICH COMPRISES REACTING A CYCLOALKANE HYDROPEROXIDE WITH A STOICHIOMETRIC EXCESS OF A CYCLOALKANE AT A TEMPERATURE IN THE RANGE 160 TO 260* C., A PRESSURE IN THE RANGE 50 TO 1000 P. S. I., AND A REACTION TIME IN THE RANGE 10 TO 200 MINUTES, AND RECOVERING A CYCLOALKANOL AND A CYCLOALKANONE AS PRODUCTS OF THE PROCESS.
2. 15. A PROCESS FOR PRODUCING METHYLCYCLOHEXANE HYDROPEROXIDE WHICH COMPRISES OXIDIZING A METHYLCYCLOHEXANE FEED IN AN OXIDATION ZONE WITH AN OXYGEN-CONTAINING MEDIUM ADDED TO SAID ZONE AT A RATE EQUIVALENT TO ABOUT 0.05 TO ABOUT 0.2 MOL OXYGEN PER MOL OF METHYLCYCLOHEXANE FEED, MAINTAINING SAID OXIDATION ZONE AT A TEMPERATURE OF 150* TO ABOUT 210* C. AND UNDER A PRESSURE SUFFICIENT TO MAINTAIN LIQUID PHASE CONDITIONS IN SAID ZONE ADJUSTING THE RATE OF FLOW OF HYDROCARBON FEED TO SAID OXIDATION ZONE TO BE SUCH THAT THE RESIDENCE TIME OF SAID FEED IN SAID ZONE IS ABOUT 50 TO ABOUT 3 MINUTES WHEREBY THE DESIRED HYDROPEROXIDE IN PRODUCED.

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