DE2031782A1 - - Google Patents

Description

Process for the selective production of cyclododecanone

The invention "relates to a method for selective manufacture of cyclododecanone, in particular a process called cyclododeeanol or a mixture of cyclododeean oil and cyclododecanone obtained by the oxidation of cyclododecan in the liquid phase, with a gas that is molecular Contains oxygen, catalytically dehydrogenated in the presence of a copper chromate catalyst in the liquid phase will.

Metallic catalysts such as nickel, cobalt, copper, etc. are used as catalysts for the production of ketones from alcohols by dehydrogenation, but these have Catalysts in the dehydrogenation reaction of crude cyclododecanol Disadvantages; for example occurs in the course a reduction in the catalytic activity of the reaction, a reduction in the degree of conversion of the cyclododecanol and a decrease in selectivity, thereby causing difficulties in a dehydrogenation reaction on an industrial scale appear. The reaction solution used in the oxy-

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m. 2. "

dation of Cyolodod @ ean with a moleloilaxen oxygen-containing (Jas is obtained in the presence of a boric acid _{compound, ester contains 9} ketones ₉ acids * alcohols, unreacted hydrocarbons and oxygen-containing compounds with high boiling points, these compounds all cause a reduction in catalytic activity, and it It is very difficult to remove this considerable amount of impurities from the hydration solution. For this reason, a very small amount of these impurities remains in the solution and greatly affects the normal course of the dehydrogenation reaction.

The inventors have made extensive studies on dehydration of cyclododecanol or a mixture of Öyclododecanol and cyclododecanone obtained by oxidizing cyclododecane in the presence of a boric acid compound were carried out in the liquid phase, with various metallic catalysts and metal-containing catalyst combinations were used here Surprisingly found that a copper thrate catalyst under certain conditions an extraordinary one Shows behavior, and with its help obtained cyclododecanone in high yield and with a high selectivity can be.

In the reference "Nafteksya" ± (2) 298-30, it is stated that the dehydrogenation of oyclododecanol with the aid of a copper chromate catalyst has already been investigated; despite the large amount (e.g. 5-10% by weight based on the starting material) of the catalyst used

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the conversion of the cyclododecanol only about $ 92, and the The selectivity to cyclododeoanone was slightly higher or less than 90 # · The exact reasons for this low Conversion and selectivity are not known, but they appear to be mainly due to the inhibitory effect of the Dehydration of the cyclododecanol to be based on olefins formed as by-products "

The inventors have now tried to determine the degree of conversion of the Cyclododecanols and the selectivity towards Gyelododecanone while maintaining a high catalyst activity and found that poisoning of the catalyst by the by-products that result in dehydration and isomerization are formed, a reason "for the decrease in activity of the copper chromate catalyst and the decrease in selectivity is. It was also found that the dehydration and isomerization Another reason for the lower selectivity is at the beginning of the reaction.

Due to further investigations on additions and modifications of the catalyst to prevent these by-products it was found that the esters and acids which are produced as by-products in the air oxidation of cyclododeoan in The presence of a boric acid compound in the liquid phase can be used to control the side reactions very effectively. Contains the cyclododecanol or a mixture of cyclododecanes ^ and cyclododeoanone esters and acids in an amount that has a saponification number of 0.02-3.0 mg / g (based on KOH), the esters and acids are attached to the active centers of the copper chromate catalyst that cause the dehydration and favor isomerization, selectively

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adsorbed, which poisons these centers and completely suppresses the side reactions * In this way it is possible to increase the degree of conversion of the cyclododecanol to more than 97 $ it is not in a position to dehydration and isomerization activity to stop, so as a result of by-products decrease the selectivity and the Umwandlungajpad and hence the dehydrogenating action. If, on the other hand, the saponification number is higher than 3.0 mg / g, the dehydrogenation activity W itself decreases, as a result of which there is also a decrease in the selectivity and the degree of conversion. This also results in a noticeable decrease in the activity of the catalyst

Furthermore, it was made that when using the Kupferchromatkatalysatörs in an excess, in particular more than 3 wt .- #, based on the charged cyclododecanes !, in the dehydrogenation of an off-change material, the saponification number is within the specified range, the dehydrating the interesting observation - and isomerization reaction increases and the conversion of the cyclododecanol, the selectivity towards cyclododecanone and the reaction rate of the dehydration of the cyclododecanols all decrease, namely as a result of poisoning by the by-products formed.

The invention is based on the observations made by the inventors and relates to a process for the catalytic dehydrogenation of cyclododecanol or a mixture of cyclododeoanol and cyclododecanone with a saponification number τοη O ₁ 02 bie?, 0 mg / g (based on KOH), the clay by oxidation Cyclododeean with a molecular oxygen

■ ORiGSWAL INSPECTED

holding gas in liquid phase in the presence of a boric acid compound, hydrolysis, alkaline saponification and purification of the reaction product were obtained in liquid Phase with the help of a copper chromate catalyst, in particular in amounts of not more than 10% by weight on the cyclododecanol is used.

The process for the oxidation of cyclododeoane with air in liquid phase in the presence of a boric acid compound is known per se, for example from the USA patent 3,419,615; in this process the degree of conversion is des cyclododecane 25 to 30 # and the selectivity to cyclododecanol and cyclododecanone about 90 # The cyclododecanol falls in the form of esters of boric acid and in the form of similar compounds. The reaction solution, which contains the boric acid ester is hydrolyzed with hot water, and the resulting aqueous Layer is separated. The remaining oil sohioht contains oyolododecane, cyclododecane !, cyclododtoanone, Esters, acids and the like. Catalysts based on nickel, cobalt, platinum or palladium have with respect to the Dehydration of this oil layer has no effect at all. Catalysts that support alumina, diatomaceous earth or copper Containing silica-alumina as a carrier also have only a low catalytic activity · The copper chromate catalyst Although it has the desired activity, it is unsatisfactory in terms of the duration of the catalytic activity.

The reason for this is that there are large amounts of acids and esters are present in such a state that the oxidizing solution obtained is merely hydrolyzed

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will. A satisfactory result can only be obtained in the presence of the copper thrate catalyst after the ulso layer has been saponified with alkali and some of the compounds contained therein have been separated from the aqueous layer, for example by distillation or the like. On the other hand, the catalysts based on nickel, cobalt or platinum low dehydrogenation activity, and the catalysts which comprise copper on alumina or silica-containing alumina as a carrier, show strong Aktivitätsver f losses. When using a nickel- or cobalt-containing catalyst, further purification of the oil solids is necessary. It is surprising that only the copper chromate catalyst has good activity if the starting material to be dehydrogenated contains certain amounts of acids and esters.

The invention is explained in more detail below

To introduce a hydroxyl group into the cyclododecane Duroh oxidation in the liquid phase in the presence of a loric acid compound offers the following procedure:

The following compounds, for example, are suitable as boric acid compounds! ^, ν,

Orthoboric acid (H ₅ BO ₅ ), boron compounds that are capable of catalytically reacting with water to form boric acid, e.g. B. dehydrated orthoboric acid in the pore of boric oxide (B ₂ O,), metaboric acid ^ "" (HBOg) _n J etc. or boric acid esters, such as trimethyl borate, triethyl borate, tributyl

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IWSPECTED

borate etc. clay these compounds are the drained, condensed boric acids such as metaboric acid etc. especially 0.05 to Q6 boric acid compounds are preferred (based on orthoboric acid) used per mole of cyclododecane

Gases containing oxygen can be air or oxygen, those with inert gases such as nitrogen, carbon dioxide, etc. can be diluted, can be used

The reaction temperature is about 145 to 180 ⁰ O, and 'the reaction is carried out either batchwise or continuously.

The first purification stage of the reaction product obtained in this way consists in hydrolyzing the boric acid ester by bringing the reaction product into intimate contact with water ^{at elevated temperatures, for example at 60 ° C. or higher.} At this stage, the dibasic acids with eight or fewer carbon atoms and the monobasic acids with five or fewer carbon atoms, which are obtained as by-products, are largely extracted into the aqueous layer together with the boric acid.

Subsequently, the ölschlcht is ait a 1 to 30 jt-strength, preferably a 3 -lgen to 10 j (aqueous alkaline solution, in particular with an aqueous NatriuBhydroxyd- or Kai iumhydroacydlö solution, at a temperature of 60 ⁰ C or higher, preferably has at about 80 to 12O ⁰ O _{9 for} five minutes to three hours, preferably 15 to 60 minutes, the remaining acids going into the aqueous layer as alkali metals, the esters being hydrolyzed and the acids formed going into the aqueous layer

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Layer. The amount of the alkali to be used is more than the equivalent amount for the complete saponification of preferably 1.5 "3-fold to the oil layer containing after alkaline hydrolysis or 0.01." To 1 wt -. ° / o dissolved alkali metal hydroxides and alkali salts. These compounds are removed by multi-stage extraction with hot water. The presence of a large amount of alkali results in a loss of organic compounds by condensation "of ketones and alcohols at the distillation stage. After the separation of the aqueous layer, the oil layer is distilled under reduced pressure to separate the unreacted cyclododecane. Further, if necessary , the high-boiling constituents separated by distilling off the oil layer containing cyclododecanol and cyclododecanone, whereby the starting material required for the process according to the invention can be obtained.

The separation of the cyclododecane is carried out so far, that the cyclododecane content is still 20% by weight or less, is preferably 5 wt. # or less.

Below is an embodiment of the method according to FIG specified of the invention.

As copper chromate catalysts, catalysts on the Basis of the common copper chromate of the Adkins type or copper-chromium catalysts, which contain manganese, barium, Sodium, potassium and the like can be added. For example, a catalyst can be prepared by using copper nitrate and barium nitrate in

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~ 9 - ■■■ · ■■.

Dissolves distilled water and reacts with an aqueous solution containing sodium hydroxide and ammonia. The received Precipitates are dried »powdered and decomposed by heating. The product obtained is with treated with an aqueous acetic acid solution and dried to obtain the desired catalyst. The catalyst consists mainly of copper (II) oxide and copper ohrom oxide. The catalyst thus obtained becomes ordinary finely powdered and preferably used in suspension in a liquid phase. But you can also do it use after granulating in a fixed bed. In general, the catalyst can be in any state used whatever of the respective requirements depends.

In the German patent specification 124 865 a fixed bed is described, since difficulties should arise in the separation of powdered catalysts; according to the invention however, the catalyst used can be purified by ordinary pressure filtration, e.g. B, with the help of a filter press Allow to settle and / or be easily separated off by simple distillation or in some other way, the catalyst activity not being reduced by the type of separation, as is set out in the examples below.

The copper chromate catalyst is preferably used in amounts of 3 Gr.ew.-96 or less, based on the oyclododeoanol. The lower limit is expediently 0.1 Grew, -9I ₉ . preferably at 0.3 wt .- ^. In the fixed bed, the reaction rate per unit weight of catalyst can be about 0.04 mol / g · hour.

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They reaction temperature is between about 180 and 24O ⁰ C, the activity of the catalyst at a temperature of less than 180 ⁰ C is not satisfactory, while at a temperature of more than 240 ⁰ C, the activity and the selectivity to cyclododecanes "are considerably reduced. The reaction rate is first order with respect to cyclododecanes! and with regard to the catalyst concentration · The reaction can be carried out batchwise or continuously. The residence time of the liquid is 0.5 to 10 hours; When the reaction is carried out in a batch manner, a conversion to cyclododecanol of 95 # or more can usually be obtained in 1 to 3 hours. In addition to the cyclodedecanol, 10% by weight of cyclododecanone, whose boiling point is close to the boiling point of cyclododecanol, is usually present in the purified cyclododecane oxidation solution.

The separation of the cyclododecanol from the cyclododecanone is difficult because the boiling point of cyclododecanol is close to that of cyclododecanone. If therefore with If this separation is necessary for the dehydrogenation of cyclododecanol, it is difficult to carry out

According to the invention, a mixture of cyclododecanol and Cyolododeoanone being introduced into the dehydration system, without the cyclododecanol having to be separated from the cyclododecanone? Cyclododecanone can also be used can be obtained in high yield. This is where the great advantages of the present invention lie

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According to the invention, a high conversion of the cyclododecanol can be maintained without the catalyst being appreciable loses activity and the reaction product therefore contains high concentrations of cyclododecanone. The reaction product can therefore directly in the next stage, for example in the oxidation, to hydroxylamine be used. In this way the fermentation according to the invention is very advantageous on an industrial scale

If the implementation is carried out in a plague bed, so can the cyclododecanone at a high reaction rate obtained by converting the cyclododecanol suppressed and the unreacted Cyolododeoanol returns to the reaction system.

A solvent can be used; but it is necessary that the solvent is inert and has a boiling point of more than 200 to 25O ⁰ C. However, since solvents with such a high boiling point are difficult to obtain at low cost and with a high degree of purity, the use of a solvent is not absolutely necessary.

The materials for the reaction vessels are more corrosion-resistant Steel, iron, glass linings, etc. used. If the catalyst is used suspended in a liquid phase, it is preferred to use a reaction vessel in the form of a tank with a stirring mechanism which ensures adequate contact between the solid particles and the liquid. Becomes the catalyst used in the fixed bed, it is expedient to use a tubular reactor or a reactor of the tank type, which of the depends on the circumstances. Is the catalyst in a

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Suspended dehydration solution, it can be filtered off while the solution is kept at a temperature above the melting point of the cyclododecanol (61 ⁰ C); However, the catalyst can also be removed after adding a solvent, such as benzene, cyclohexane or the like, to the solution, or by allowing it to settle or by distillation or extraction. Any suitable separation can be made depending on the circumstances.

The invention is illustrated by the following examples and comparative examples:

example 1

A mixture of cyclododecane. and Orthdborsäure (H, BO ~) was dehydrated in a nitrogen stream and oxidized with air under atmospheric pressure at 16O ⁰ C until the cyclododecane was converted to 20 $>. The reaction solution obtained was hydrolyzed with an excess of water at 100 ^° C. and then washed with water. The solution was then treated with a 5% aqueous sodium hydroxide solution, the amount of which corresponded to about twice the saponification number, for one hour at 100 ^° C. and then washed twice with water. The reaction solution thus obtained was rectified at a pressure of 100 mmHg to separate the cyclododecane. Then, the rectified reaction solution was simply distilled at a pressure of 50 mmHg to separate the cyclododecanol. A mixture of cyclododecanol and cyclodode-

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canon with the following composition: 0.7 wt .- # Gyolododecan, 93.1% by weight of cyclododeeanol and 4.9% by weight of cyelododecanone, that has a saponification number of 1.2 mg / g (based on

KOH) had α

238 g of this mixture and 2.4 g of a copper chromite catalyst were placed in a provided with a stirrer and a condenser reaction vessel and dehydrated for two hours at 200 ⁰ C ,, The catalyst was then filtered off to give a slightly colored white Pestsubstanz was obtained “The solid substance obtained in this way was dissolved in benzene and analyzed by gas chromatography. This resulted in a degree of conversion for the cyclododecanol of 98.4 1 * and a selectivity for cyclododecanes of 97r ² $> * Furthermore, the formation of a small amount of cyolododecane and cyclododecene could be observed.

The filtered off catalyst was washed with cyclohexane, dried under reduced pressure and used for the dehydrogenation of a further batch. This way of working was repeated every time the catalyst was reused.

A mixture of cyclododecanol and cyclododecanone with the composition given above and the like Saponification number was used as the starting material. the Results for "Use of the regenerated catalyst for the second approach and for the following approaches are given in Table 1.

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Table 1

Number of times the catalyst has been reused

2. Use

3 · Use

4. Use

5. Use

Dehydration temperature ( ⁸ O)

200

205 ,.

205

210

Reaction time (hours)

2.0 2.5 2.5 2.5

Oyolodode
canolum-
change
(*) Selecti
vity be
quickly
Cyclodo
deeanon 97.5 97.8 98.0 95.7 97.1 98.1 98.2 97.9

The above results show that there is practically no loss of activity of the catalyst has taken place.

Examples 2 to 5 {Comparative Examples 1 to 4-

In the same manner as in Example 1, the reaction solution was prepared obtained by oxidation of cyclododecane, which hydrolyzes under the same conditions as in Example 1, however was saponified under alkaline conditions under the conditions given in Table 2 and then distilled The resulting mixture of cyclododeeanol and cyclododeeanone was dehydrated under the conditions given in Table 2; the results are given in Table 2.

Catalyst: powdered copper chromate Conversion: batchwise
Reaction time: 2.0 hours (dehydration) Mixture of Oyelododeo & nol and Cyclododeeanone: 238 g

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Table 2

Composition of the mixture of cyclododecanol and cyclododecanone

Dehydration conditions

Cyclodo- Cyclodo- Veraei- Copper- Temperadecanol decanon fung number chromate door (*) (*) '(KOH mg / g) (g) ( ⁰ C) results

Conversion selectivity

mentation of deed related

Cyclodo- borrowed Cyelo-

decanol dodecanone

Ratio catalyst / cyclododecanol (wt .-? I)

Example t 94.2

Comparative Example 2 94.5

92.7

5.3

■ 9.3.

4.9

0.05

00 988 > 3 93
92 , 7 5 , 2
, 9 1
2 "8th
, 9 co S.
N)
N) Comparison
example 1 Il It , 7 CO Example 5 93 , 0 5 , 2 1 ,8th

0.01

4.7

2.4 205 (2nd use)

■ Μ "-)
4.5

215

»(») 215

12 (fri-205 shear catalyst)

12th

215 97.3

98.0

1.1

98.0 97.6 96.2 97.3 93.1 92.5 95.8 95.1 94.1 93.1 90.3 91.0 92.1 90.5

2.0

5.4

1.1

5.4 5.4

Comparative Examples 5 tola IS 1

238 g of a mixture -aas Syöl © i © iö®CM © i umä

with the same Znaaaeettsetsiiig "as la Bei§jd @ l 1

Starting material - uses tiad ia

Catalysts in liquid aase ioll ^ isl © »^ * © i ©

nits are in table f aagögeliößio -SMq door at the Behytelens
mosphärendruok and the

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door at the Behyteleresg "pastry! © § § _D iöi?

Comparison «- Xittaiysatoi ¹ ""- Hesago .. üqb

for example "■ 'tal ^ sstose ($): l« Sg mm. MtIt la «

»Ickel-f oaes? I® ■ & _§ 4 43

(Hi 20 i) (Srleehes

Hl ^

earth (Hi 50 $)

(fresh kata-. ■

lyser)

7 cobalt diatoms - 2,4 '- & _f t 92 »5 earth (Co 50 Ji)

(fresh catalyst)

8 Haney cobalt 4.8 11.3 94.8 (fresh catalyst).

9 Chroe clay 4.8 1.3 (fresh catalyst)

10 platinum cabbage (Pt 5 J *) 5.2 40.4 84.2 (fresh catalyst)

11 Baney copper 4.8 62.3 96.3 (early catalyst)

Patent claims t 009 886/2223

BAD ORiGJjSlAL

Claims (1)

P a t e nt claims (t) Process η for the selective production of you Oyclodod · canon, characterized in that one uses yclododeeanol or a mixture of Cyclododecane! and Oyolododecanon «it a Yereifungsiahl τοη 0.02 to 3.0 mg / g (based on EOH) obtained by oxidation τοη Oyclododeoan in the liquid phase with a molecular oxygen-containing gas in the presence of a boric acid compound and subsequent hydrolysis, alkaline saponification and distillation were catalytically dehydrated in the liquid phase in (in the presence of a copper chroaate catalyst. 2 · near to claim 11 characterized by the fact that one the lupferohronatkatalyßator in quantities τοη no more as 3 parts by weight, based on the cyclododecanol, used. 3. Terfahren according to claim 1 or 2, characterized in that di leads. net that the dehydrogenation at about ISO to 240 ⁰ C by «-