DE1287072C2 - PROCESS FOR OXYDATION OF SATURATED HYDROCARBONS - Google Patents

Description

formation of alcohols proceeds with high yields,

however, serious difficulties arise in attempting this technical teaching lower-boiling hydrocarbons, such as hexane and cyclohexane, to be used.

The invention relates to the oxidation of saturated In itself is the attempt to this known teaching

th C ₄ - to ^ - hydrocarbons with molecular the oxidation of saturated C ₄ - to C ₈ - carbon oxygen in the presence of metaboric acid or hydrogen to apply, obvious. As seen above with lower boric acid hydrate including boron, the yield can in some cases be somewhat improved by acid anhydride under conditions under which application of the known teachings a high yield of oxidation products and be.

a great economy of the oxidation process with the volatile C ₄ - to ^ -hydrocarbons

can be achieved. 60, however, it has not been possible to date to

It is generally known (cf. the procedures given below using molecular acid references), hydrocarbons, e.g. B. fabric to develop, with the yields of those Cyclohexane, to oxidize selectively to produce products like those comparable to those with the higher-boiling Koh-Cyclohexanol and cyclohexanone. In the case of lenwasserstoffen are achieved, and being the same method for the production of adipic acid, phenol, 65 early operation from an economic point of view Cyclohexanone and other chemical substances are favorable from a perspective, technical importance includes one of the main- For example, Bashkirov and Mit-

HrhonK process stages the selective oxidation of workers that it is necessary to achieve a high efficiency

I ^ ο / υ / ζ

3 4

prey is necessary to work with very low oxygen / water vapor partial pressures that work above pressures; In higher-boiling hydrocarbons, the oxidation system containing the maximum value specified in patent 11 58 963 can be, but not be greater than P, which results from the oxygen partial thickness of the oxidizing agent with only the following equation:
minor changes to the reaction system 5

be lowered. On the other hand, in the case of oxidation it is login ** = 0.01077-1.087 (1)

from C ₄ to Cg hydrocarbons not possible,

the oxygen partial pressure to be calculated in the same way and preferably not greater than P, which results from low, without making the process uneconomical, the following equation:
and becomes inexpedient. The heat supply that er io

it is necessary to maintain the reaction conditions _{- log 10} P = "- 0.011127-1.414, (2)

becomes excessively large in these hydrocarbon systems, where T is the reaction temperature in degrees Celsius

It is already known that the means distance.

of water in the oxidation of hydrocarbons. According to the invention, the oxidation is preferred Substances such as hexane are of great importance, but are used intermittently or continuously have the gaseous molecular oxygen associated with water removal at a Difficulties a successful application of the reaction temperature from 140 to 180 ° C with a Function of the oxidation of higher boiling mixtures of liquid hydrocarbons and meta-hydrocarbons carried out in the presence of boric acid on ao boric acid. During the implementation will lower boiling, more volatile hydrocarbons, such as a gas mixture, the water and hydrocarbon Hexane, prevented. and usually also contains inert gas such as nitrogen,

For example, in the discussion it was withdrawn from the reaction zone. With this Durchan that of W. G. Toland in the Fifth World leadership of the method according to the invention is the Petroleum Congress reported work by Bash- 25 reaction adjusted so that the partial pressure of the kirov and co-workers added, by H. M. Stan -wassers in the escaping gas mixture no greater ley by Distillers Co., Ltd. executed: as P in equation (1), and preferably not greater

as P Li is Equation (2).

“However, it may very well be that some- Through the practice of the present invention

tiger, restrictive factor of the 30 can at the rate of hydrocarbon oxidation the removal of the water th from over 80 to 85 per cent. with the formation of proder Esterification is. As long as there are considerable products from which the corresponding alcohols are made Add amounts of water in the reaction medium and allow ketones to be obtained easily, with a high host counter there is obviously considerable ability to be achieved in operation. A special stake of free alcohols, which are oxidizable, the advantage of the invention, namely the specified are. Regulation of the partial pressure of water in the vapor phase,

In attempting this process or this it is that the reaction selectivity does not suffer on the lower and more volatile ones, if relatively high oxygen partial paraffins are used, these limits will be applied, which are immediately economical, and indeed we are in 4 ° to enable the oxidation process to be carried out, our laboratories have not succeeded in this. If higher oxygen partial pressures are used, the working method is applied to the lower paraffins, namely a larger proportion of the heat required for the evaporation of pentane and hexane, which in our opinion largely goes back to this - amount covered by the heat of reaction than with lead. «45 Use of lower O ₂ partial pressures.

According to the method according to the invention

The patent 1158963 relates to a process for oxidizable hydrocarbons including oxidation of a saturated hydrocarbon with 4 other cyclopentane, cyclohexane, cycloheptane, up to 8 carbon atoms, such as cyclohexane, η-hexane, cyclooctane, methylcyclohexane, the dimethylcyclo-methylcylohexane, cyclopentane or n- by 50 hexanes, n-pentane, η-hexane, n-heptane and the Me reaction with oxygen, preferably a molethylpentane. In a preferred embodiment, a gas containing oxygen, in a reaction, is a mixture of the hydrocarbon and ion zone, which is a mixture of the hydrocarbons, an amount of metaborative in the liquid phase that promotes the yield, with metaboric acid or an acid or a lower boric acid hydrate, includes lower hydrate of boric acid, at a tem- 55 It is particularly expedient, first a Aufperatur of 140 to 180 ⁰ C, if desired, of orthoboric acid in the coal presence of a solvent, wherein hydrogen is to produce in a slurry. This suspension is then dehydrated water vapor partial pressure in the above the liquid phase, for example, by passing a gas through it at elevated temperature and / or removed from it, to maintain the vapor phase, which, expressed in 60 at least a part and preferably practically kg / cm ² , is not greater than P, which results from dehydrating all orthoboric acid. Other methods for the production of meta-laboratory can also be used in the equation

log ₁₀ P = 0.0175Γ -3, acid, or a lower hydrate and the mixture

can be applied with the hydrocarbon.

where T is the reaction temperature in degrees Celsius 65 the metaboric acid or the lower hydrate

means results. in an amount of at least 1 mole of the boron compound.

It has now been found that good results are also expressed as metaboric acid per 6 moles oxidized

can then be obtained when used with somewhat higher hydrocarbons. Since economic envi-

Degree of conversion at at least 4 ° / · hydrocarbon dation so that the water vapor pressure substance, this corresponds to at least about 0.4Vo in the one leaving the liquid reaction mixture Boron compound, expressed as metaboric acid, is a vapor flow 0.3 to 100 Vo of P according to the equation added to the weight of the coal

hydrogen and boron compound. Because of some j log, ₀ P - 0.0107i - 1, UK /,

Difficulty handling the slurry. .

in the reaction vessel and the separation of where T is the reaction temperature m urad Celsius solids, it is generally not expedient, means, is, however, greater than the highest value of the boron compound, expressed as Metaborsäuve, of patent 1158963, which is derived from the equation in Remember to use that about 20 weight- «>

percent of the mixture of hydrocarbons and logio ^ ^{0 =} 0.0175Γ — 3

Exceed boron compound. results

In the method according to the invention, if lower boric acid hydrates, e.g. B. boron oxide,

preferably used metaboric acid. In addition to the used, pure oxygen and, if applicable, lower hydrates of boric acid, cooling can be used in the reaction. It includes boric oxide and tetraboric acid. If lower is possible, so large amounts of the lower hydrate hydrates are used and to use the partial pressure of the that this hydrate reacts with the water in the water in the vapors above the reaction mixture, which is formed during the reaction or above the equilibrium pressure, the tendency never with the starting materials in the reaction mixture whose hydrates are introduced into higher hydrates and even in * °, so that the partial pressure of the water is covered with metaboric acid. not in the vapor above the reaction mixture

It is an advantage of the invention that is generally greater than P, as defined above, without the necessity higher hydrocarbon conversions depending on the agility of vapor removal from the reaction throughput can be achieved without a zone. Of course, modifications are possible Yield reduction occurs with such a higher 25 in operation possible in such a way that the process Conversions in the known oxidation process when using these lower hydrates adiabatically go hand in hand. or can be operated with a supply of heat.

The oxidation according to the invention is carried out in the same way. carried out that about 4 to 25%>, expediently 8 as described above, it is essential that the water bis 20% and preferably 10 to 15% of the carbon vapor partial pressure of 3 ° in the exiting vapors Hydrogen per pass in a continuous among the restrictive ones mentioned above System or per batch oxidation conditions is 0.3 to 100% of P, it is for are oxidized. an economical operation when using the

Appropriately, the mixture of boron compound, lower hydrates is only necessary that the water, preferably metaboric acid, and hydrocarbon partial pressure in the vapor above the reaction to an oxidation temperature of 140 to 180 ° C mixture is not greater than P.
heated and a molecular oxygen containing In the practice of the invention,

Gas passed through. Pure oxygen can, although the hydrocarbons to be oxidized are such can be used, but is preferably moles with 4 to 7 carbon atoms and the more oxydacular Oxygen mixed with inert gas, e.g. B. 4 ° tion in the absence of a solvent or large Nitrogen. Oxygen concentrations of lower hydrates can be carried out that are applied above or below the procedure often requires a supply of heat in order to which are in the air. In general, it is preferable to obtain sufficient hydrocarbon to be drawn in Oxygen concentrations of 10 percent by volume boil and steam is removed so that the water or below to apply in the oxidizing gas, 45 partial vapor pressure in the exiting gases, such as about the possible formation of explosive mixtures referred to above, is maintained while one to avoid. works at the desired reaction temperature.

During the oxidation, a gas mixture is created. The heat can be supplied in several ways, which is in the oxidizing agent introduced is preferably from the reaction zone as steam Inert gas contained in addition to about 5 ° un * consumed, withdrawn, condensed and oxygen from the water, Water and vaporous coal- heated hydrocarbon separated and / or hydrogenated contains, continuously from the reaction steam and zoned as steam in the reaction zone removed. This vaporous hydrocarbon leads. Instead, the heat can flow through the wall fabric can be condensed, at least partially from fertilizing the reaction vessel, with the help of heating water separated and fed as a liquid into the coil in the reaction zone and the like action vessel are returned. Usually will.

depends on the amount of water in the reaction zone in the process of the invention

and (^ hydrocarbons used in the emerging from the reaction zone Ga, then it is häufisen ger possible substantially on the oxygen concentration to work adiabatically. That is, the liberated in the gaseous oxidant and the encryption ⁶ ° by the reaction heat Another roughly sufficient source of water to evaporate water, however, includes heat required and hydrocarbons to feed gases to cover that which serves as feed.

Hydrocarbon mixture and reflux hydrocarbon The process according to the invention can also under

bons, from which part of the water corresponds in general ⁶ 5 using a solvent in the Reaktionsnen by decanting off or distilling off be conducted mixture. Appropriate solution has been removed. medium are those that change during oxidation

When using metaboric acid, the oxy-

Separate participants and the reaction products.After completion of the oxidation contains the

permit. Appropriately, organic compounds are a considerable amount of the reaction mixture

without reactive secondary or tertiary carbon alkanols in the form of a boric acid ester. Desired-

used atoms. In the case of primary carbon, the boric acid ester can be obtained as such

atoms standing hydrogen atoms are at the front 5. To the alkanol or cycloalkanol as

lying implementation practically inert. To gain secondary such, it is expedient to use the oxy-

or tertiary carbon atoms standing water dation mixture after removal of unreacted

However, substance atoms tend to undergo hydrolysis in this reaction to the system

a much higher level of responsiveness. throw, whereby the released alkanol or cyclo-

These compounds preferably boil between io alkanol easily by distillation or extraction Hydrocarbon to be oxidized and the am tion can be obtained. The hydrolysis can lowest boiling oxidation product. Too easy, for example by adding water play for such solvents include under the oxidation mixture after removing the carbon other hexamethylethane, substituted benzenes and hydrogen and heating to z. B. 50 to 150 ° C halogenated hydrocarbons. 15 perform. Other known ways of working, e.g. B.

It should be noted that the counter-alcoholysis or transesterification can also

wait for the characteristics of a solvent to be applied.

Reaction system can be changed. If the lo- The following examples illustrate the invention,

The solvent boils higher than the hydrocarbon, parts and percentages refer to the product

then it is possible to weight the implementation below nearly 20 if nothing else is given.
perform adiabatic conditions, and im

Example 1 can even be used in the case of C _{4 to ^ hydrocarbons}
cooling will be required.

For a successful implementation of the invention, 2711 parts of cyclohexane are required with about 450 parts

According to the method, a careful adjustment of finely ground solid orthoboric acid is mixed. the

the reaction conditions necessary. So the Oxyda- formed slurry must be in a glass-lined

tion temperature in the range from 140 to 180 ° C and the reaction vessel, which is equipped with guide surfaces, a heating

preferably between 160 and 170 ° C. For a jacket, a steam vent, a cooler, a

the actual implementation in a test vapor-liquid separator, a water separator

system, an exact reaction temperature is provided and a reflux return line is provided,

chooses. Then the reaction pressure is increased to about 165 ° C with stirring or shaking.

The coal entering the reaction is viewed and a stream of nitrogen is passed through it. the

Hydrogen (with or without a solvent), orthoboric acid is easily dehydrated

Amount of the inert and practically completely introduced into the reaction vessel with the formation of metabo-

Ingredients and the amount of water that removes 35 acid, being a gaseous mixture of nitrogen,

must be calculated so that the volume of water vapor and cyclohexane is removed. That

organic substances, inert components and counter- Cyclohexane is condensed from the steam, from

if necessary, unused oxygen, which the re-water is separated and returned to the reaction vessel.

Action vessel left as steam, sufficient to run the.

Water pressure within the limits given above- 4 ° The formed slurry of metaboric acid

to keep zen. Then the heat transfer to and cyclohexane is by adjusting the heat

The reaction vessel is adjusted so that the desired feed to the jacket, as required, at 165.degree

th temperature and pressure conditions are met. held. A gaseous mixture of oxygen

In another possible type of operation, nitrogen with an oxygen content of 10 vol-

the same calculation is made, but the heat percentage is added to the reaction vessel under the

transition adjusted so that the desired amount of liquid surface with a speed of

of organic vapors goes overhead, during about 4 volumes per minute (1 atm. and 25 ° C) each

After the pressure is initiated to control the temperature in the reac- approximately 3.8 volumes of slurry

tion vessel is set. The pressures can at- kuizer time, the oxygen absorption is practical

for example in the range from 0.7 to 57 atmospheres. 50 complete. The pressure in the reaction zone is mil

In the case of a cheap and economical operation, the help of a pressure regulator valve on the steam

of the method according to the invention, the vapor-liquid separator leaving vapors at sthj

mixture cooled from the reaction zone to water 18.13 kg / cm ² kept. Under these reaction conditions

and to condense hydrocarbons. This is the oxygen partial pressure at the inlet

condensed substances are separated, for example 55 entry point into the reaction zone about 1.08 kg / cm ^:

by decanting, and the hydrocarbon, taking into account the cyclohexane vapor pressure:

returned to the reaction zone. Heat saving of 7.35 kg / cm ² at the reaction temperature voi

Nits are determined by heat exchange between the temperature in 165 ° C, i.e. H. 10 ° / o of (18.13-7.35).

the reaction zone returning hydrocarbons During the reaction becomes a vaporous

substance and the 6 ° mixture emerging from the reaction zone, the cyclohexane, water and nitrogen

Steaming is achieved for such a heat removal continuously from the reaction zone

Exchange a direct contact is applied, then drawn and condensation of water takes place

also another liberation of the returned cyclohexane cooled The vapors are in de

Hydrocarbon of water. The upright separator is separated from the condensate

The heat required to maintain the conversion is provided before 65 After the water has been separated off by means of dean

The liquid cyclohexane is preferably fed into the reaction by heating the cycle carbonation

Hydrogen returned to the reaction before its introduction. Among those described above

Zone delivered reaction conditions is the water vapor partial

pressure in the gases emerging from the reaction zone at about 1.4 kg / cm ² . The reaction continues until about 10.5% of the cyclohexane has reacted.

When the reaction has ended (about 6 hours), the reaction mixture is mixed with 200 parts of water and heated with stirring and reflux (about 70 ° C) for 1 hour to hydrolyze the boric acid esters. The resulting mixture is filtered to separate solid boric acid and the filtrate is decanted, to separate an organic phase from an aqueous phase. The aqueous phase is with a low Amount of cyclohexane extracted, and the extract is combined with the organic phase. The organic Phase is extracted with a small amount of water to remove boric acid. The received Mixture is distilled to give cyclohexane as a passing portion of a remaining Separate cyclohexanol fraction. The cyclohexanol fraction makes up about 340 parts and contains cyclohexanol Cyclohexanone and other oxidized cyclohexane products as the remainder. The molar yield increases Cyclohexanol and cyclohexanone is 80%.

Example 2

The procedure described in Example 1 is repeated with the exception that the pressure in the reactor zone is maintained at about 23.52 kg / cm ² . Under the reaction conditions of the oxygen partial pressure is at the entry point in the reaction zone is about 1.6 kg / cm ² in consideration of the Cyclohexandampfdrucks of 7.35 kg / cm * at a reaction temperature of 165 ⁰ C (ie 10V. From 23.52 to 7, 35). The vapors are drawn off as described in Example 1. Under these reaction conditions, the steam partial draft in the gases leaving the reaction zone is about 2.1 kg / cm ² .

The reaction is continued until about 9.0% of the cyclohexane has reacted. The reaction mixture is worked up as described in Example 1. The molar yield of cyclohexanol and cyclohexanone is 80%.

By way of comparison, let the importance of maintaining the temperature within that specified Range of 140 to 180 ° C illustrated.

The procedure described in Example 1 is repeated except that a slurry dehydrated by 100 parts of orthoboric acid in 1000 parts of cyclohexane and the resulting mixture is oxidized from metaboric acid and cyclohexane for 4 hours at 200 ° C. Gaseous oxidizing agent, which contains 4 percent by volume of oxygen in nitrogen, is mixed with the cyclohexane at a rate of 137 volumes per hour and 1.4 volumes of slurry.

The reaction mixture is worked up as described above. There is a yield of cyclohexanol and cyclohexanone of about 75.7% with a degree of conversion of cyclohexane of about 6%. These figures clearly show the importance of maintaining an oxidation temperature does not exceed about 180 ° C, so that the desired high yield at the method according to the invention is achieved.

For further comparison, a mode of operation that is not in the area of the Process according to the invention is initially a slurry of 900 parts of cyclohexane and 231 parts of boron oxide produced. About 100 parts per million (= 0.01%) cobalt, based on cyclohexane, are added as cobalt naphthenate.

Air moves through this slurry at a rate of about 170 volumes per hour and 1.3 volumes of slurry. The reaction is carried out at a temperature of 190 ° C and a pressure of 14 atm. The oxygen absorption reaches after a reaction time from 55 minutes about 32 volumes.

The reaction mixture is worked up as described in Example 1. The conversion of Cyciohexane is about 12% with cyclohexanol of 67.6 and cyclohexanone of 3.9 ° 0. The overall yield in cyclohexanol and cyclohexanone of 71.5% shows that in this example described procedure no or almost no improvement in yield compared with a cyclohexane oxidation without using a boron compound.

For further comparison, the experiment is made, the oxidation described in Example 1 in a Temperature of 130 ° C. There was no implementation. Hence the meaning of the illustrated lower temperature limit specified for the process according to the invention.

The process according to the invention can be carried out without a catalyst. With the previously known Process in which no boron compound is used, it is necessary to use small amounts of a catalytic Substance, e.g. B. a cobalt salt, to use to make cyclohexane with success with molecular To be able to oxidize oxygen to a mixture containing cyclohexanone and cyclohexanol. It however, it has been found that in the present process, when molecular oxygen is mixed with the Mixture of metaboric acid and hydrocarbons under the specified conditions in contact is brought, do so far as catalysts for oxidations Substances used without boric acid have practically no effect without possibly an adverse effect Have an effect and are therefore not required initiators such as aldehydes, ketones and peroxides can be used. Examples of such initiators are cyclohexanone and hydrogen peroxyc and called tertiary butyl hydroperoxide.

Claims (2)

Cycloberane a. The disadvantage of the known process claims is the generally low yield of oxidation products. 1. Process for the oxidation of saturated It is known that the yields in the Oxyda-Hydrocarboncn with 4 to 8 carbon 5 ion of hydrocarbons to the corresponding atoms, such as cyclohexane, η-hexane, methylcydo alcohols using molecular hexane, Cyclopentane or n-heptane, can be increased considerably by oxygen, set with oxygen, preferably a mol- Thus, for example, in the USA patent, hydrogen in the liquid phase with metaboric acid 1931501 states that, in the oxidation of or a lower hydrate of boric acid, it contains hydrocarbons, such as paraffins and naphthenes, at a temperature of 140 to 180 ° C, ge - Which boil over 180 ° C, with molecular oxygen, if desired in the presence of a solvent, by addition of at least 2 percent by weight of a water vapor partial pressure in the 15 weak inorganic acid, such as boric acid or above the liquid phase and / or its anhydride, to the hydrocarbons a vapor phase removed from this, increased alcohol formation is achieved, which, expressed in kg / cm *, not greater than P, Following the procedure of the USA patent that results from equation 19 47 989, hydrocarbons with molecular ao rem oxygen is oxidized in the presence of boric acid, log ₁₀ P = 0.0175Γ -3, which results in an increased yield of alcohol will. Preferred temperatures for oxidation where T is the reaction temperature in degrees Celsius between 160 and 200 ° C. In the patent, results, characterized marked, it is indicated that the process assumes in all cases that a water vapor partial pressure 25 can be used in which hydrocarbons are also maintained , which is greater than the highest value that can be oxidized in the absence of boric acid, according to the above equation, but not greater than P, which can be derived from the equation Nauk. SSR, Vol. 118, No. 1 , 1958, pp. 149 to 152) have shown that paraffins, such as tridecane, with sticking log, ₀ P = 0.01077-1,087, 30 fabric-oxygen mixtures containing 3.0 to 3.5 "/ 0 Sauer contain substance at 165 to 170 ° C with an additive where T is the reaction temperature in degrees Celsius of 5 ° / o boric acid can be oxidized. It means advertising and P in kg / cm ² , results. the high yields of alcohols and ketones 2. The method according to claim 1, characterized given (report by WG ToIand at the Fifth indicates that the water vapor partial 35 World Petroleum Congress, 3.6.1959 [see Paper 15 - pressure, expressed in kg / cm ² , with a Section IV, "Proceedings of the Fifth World Petro, which is greater than the highest value according to leum Congress"]). those mentioned in the first place in claim 1 In addition to boric acid and anhydrides, also other Equation, however, is not greater than P, which uses their boron compounds. For example, from equation 40 in French patent 11 66 679 the The use of boric acid esters, such as tributyl borate, log, ₀ P = 0.011127 "-1.414, is described for hydrocarbon oxidations. It is stated that the oxidation of where T is the reaction temperature in degrees Celsius of higher hydrocarbons, both of means results. 45 paraffins as well as naphthenes, with molecules rem oxygen in the presence of a boron compound of the type described above readily under BiI-