DE1468121A1 - Process for the production of adipic acid and / or epsilon-caprolactone - Google Patents

Description

PATENT LAWYERS

DR.-INQ. H. FINCKE DIPL.-INQ. H. BOHR DIPL-INQ. S. STAEQER Ffrnrod · 2ββ0 «0

8 MUNICH S ₁ M0ll * ritrci6 «31

16 JUL11968

Folder 19977 - Dr P / hr Caee H. 17227

P H 68 121.1

DESCRIPTION to the patent application of

Company IMPERIAL CHEMICAL INDUSTRIES MMITED, London / Großbr.

concerning

Process for the production of adipic acid and / or Fe-Capro-

laoton

PRIORITY: December 23, 1963 - Great Britain

Pie invention relates to a process for the production of adipic acid and / or ε-caprolaetone by oxidation in the liquid phase of. Cyclohexane with molecular oxygen in the presence of an aldehyde at temperatures above ⁰

New Uri

O ₁ -Jl "../ '.

It is known that when certain reaction conditions are used, cyclohexane can be oxidized into various oxidation products such as, for example, cyclohexanol, cyclohexanone and, with splitting of the carbon ring, even to ε-caprolactone and adipic acid. In a known process for the oxidation of cyolohexane in preferably cyclohexanol and cyclohexanone, it is known to add small amounts (0.1 to 2% by weight) of an initiator, such as aB _o an aldehyde, to the reaction mixture. However, the process must be carried out at an elevated pressure of 3 »5 to 35 and aueserdem it supplies no or only little from the higher oxidation products of adipic acid and £ -Caprolacbon, so that for the production of said both important in the synthetic fibers industry substances another Oxidation must be made. In addition, this process leads to the formation of considerable amounts of low molecular weight monobasic acids, such as eg. Acetic acid and formic acid "

According to a non-prepublished proposal, the oxidation of cyclohexane to higher oxidation products old auxiliary e molecular oxygen in the presence of an aldehyde as sogenanntesKooxydationsverfahren performed Here, the aldehyde to a Ilonoearbonsäure oxidized, while the cyclohexane preferably caprolactone ^ oxy-

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is dated.

It has now been found that the entrance to a V «drive designated species particularly high levels of ^ -caprolactone and adipic acid can be obtained if it is ensured that the amount of aldehyde present in the reaction mixture increases every point in time is small

So the present invention provides a method for the production of adipic acid and / or £ -caprolactone proposed by oxidation in fltist Jer phase -voa Cyolohexan with molecular oxygen in the presence of an aldehyde hot temperatures above 45 ⁰ C, welohes characterized in that dae aldehyde is added to the reaction in portions or continuously, in such a way that the molar ratio of aldehyde and cyclohexane in the reaction mixture does not exceed 1:10, preferably not more than 1:50, during the reaction. ·

The aldehyde used as a co-oxidant can be a straight one or branched, saturated aliphatic mono- or dialdehyde or an aromatic aldehyde. examples for suitable aldehydes are isohutyraldehyde, adipaldehyde, Benzaldehyde and tolualdehyde. It is preferred that the

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Aldehyde is a lower straightforward aliphatic aldehyde such as acetaldehyde, propionaldehyde or n-butyraldehyde.

The total amounts used throughout the course of the reaction of cyolohexane and aldehyde reacted and not critical and that used molar ratio of aldehyde to cyclohexane Iranη for example be within the range of 1s10 to 4: 1. A very useful ratio of aldehyde to cyclohexane Let about 1s 1. TJm but a good yield of ε-oaprolactone and adipic acid, it is essential that the molar ratio of aldehyde to cyclohexane in the reaction mixture is small at all times. This condition can can be achieved, for example, by converting the aldehyde, preferably continuously, into a relatively gradually pushing in a large volume of cyclohexane.

The molecular oxygen containing «gas can be oxygen, Air or oxygen diluted with a gas such as nitrogen, carbon dioxide or carbon monoxide, if this gas is inert under the reaction conditions, it is preferred to carry out the process according to the invention under perform non-flammable conditions.

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The reaction pressure should be sufficient for the cyclohexane and to keep the aldehyde in the liquid phase, and should suitably be in the range of atmospheric pressure up to 50 at or above "move.

A liquid diluent can be used, especially when the co-oxidant is a volatile aldehyde, such as acetaldehyde. The diluent should be miscible with the reactants and, if significant amounts of water are formed as a result of the oxidation reaction, the diluent should be miscible with water. Examples of suitable diluents are: aliphatic carboxylic acids such as acetic acid, esters such as methyl acetate, and ketones such as acetone. It is preferred that the diluent do not contain: CH or JCH ₂ groups.

The temperature at which the inventive method is carried out should be above 45 ⁰ C and preferably not exceed 135 ⁰ C. The temperature used in each case depends on whether a catalyst is present in the reaction mixture. The catalyst preferably contains a transition metal or transition metals, such as cobalt, manganese, nickel, vanadium, chromium, titanium or Huthe-

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nium, which in a very convenient manner in the reaction mixture can be introduced as a salt of an organic acid, such as acetate, stearate, naphthenate, oleate, Benzoate, Salicylate, AcetÖacetat or Acetonylacetat »

In Beaktionstemperaturen below 85 ⁰ C, it is desirable and at temperatures below about 75 ⁰ C, especially below 70 ⁰ C, it is essential that a transition metal catalyst is present, in order to achieve a reasonable reaction rate. The preferred concentration of the transition metal catalyst depends on the reaction temperature and the temperature of the transition metal. In general, it is preferred that an amount of catalyst be used which has a concentration of not more than 0.1, in particular from 0.0001 to 0.01 Wt .- #, transition metal, with respect to cyclohexanes. As the reaction temperature is increased, the amount of catalyst can be decreased. An increase in the catalyst concentration tends to increase the yields of the desired cyclohexane oxidation products, while on the other hand the ratio of epsilon-caprolactone to adipic acid in the oxidation product decreases. A catalyst containing cobalt is the most effective catalyst. However, since cobalt tends to undergo a conversion of epsilon-caprolactone

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Cobalt catalysts are preferably used in smaller concentrations to cause undesired compounds than all other transition metal catalysts, such as vanadium or chromium catalysts, which are less likely to promote the undesired conversion of epsilon-caprolactone vx. It is preferred to use a catalyst mx which contains both cobalt and chromium and in particular one which contains a predominant amount of chromium, such as, for example, 5 parts chromium to 1 part cobalt.

While the presence of a transition metal catalyst at temperatures of 70 ^° C. and above can be advantageous, it is preferred that a transition metal catalyst is either not present at all or only in very low concentrations, for example not above 0.0010 wt .- ^ transition metal , with respect to cyclohexane, go beyond if the metal is cobalt or another catalytically very active metal int, and not exceed 0.01 wt .- # transition metal, with respect to cyclohexane, if the metal is chromium or another, less catalytically active metal Metal is. Furthermore, at temperatures of 95 ^° C. and above, it is preferred that the amount of the catalyst used does not provide more than 0.0005% by weight of transition metal, based on cyclohexane.

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In a preferred Aueführungsart of traversed no catalyst is used and the reaction temperature between 95 ⁰ C and 115 ⁰ G.

Whichever reaction temperature is used, the reaction can be initiated. For example by UV light j ozone; Hydrogen peroxide; an alkyl hydroperoxide or

a dialkyl peroxide of the formula R.0OH or R.0.0.R, in which R is an alkyl group such as tertiary butyl; Eetonperoxyde, such as methyl ethyl acetone peroxide; Diacyl peroxides such as Diacetyl peroxide or cyclohexylsulfonylaeetyl peroxide; Dialkyl peroxydicarbonates such as diisopropyl peroxydicarbonate; Peroxyesters such as tert-butyl perbenzoate; and azo compounds, such as azo-bis-isobutyric acid nitrilo ozone can expediently be introduced as Gfemisoh with oxygen, which Contains 0.5 to 4 vol .-? S ozone.

Unless the ratio of total cyclohexanes to total aldehyde is high, it is preferred that the process under semi-continuous conditions, for example with continuous supply of aldehyde and intermittent addition of cycloparaffin, or under continuous Conditions is executed. It is further preferred that when the

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Aldehyde introduced into the reactor at various points will.

Raising epsilon-caprolaoton and adipic acid can be the reaction product contain other cyelohexane oxidation products such as cyclohexanone and cyclohexanol. It is preferred these other cyclohexane oxidation products, in particular Re-feed cyclohexanone and cyclohexanol to reduce aldehyde consumption. It is further preferred To feed cyclohexanone and cyclohexanol again in such amounts that practically zero production Cyclohexanol and cyclohexanone is obtained. The respective amounts of cyclohexanol and cyclohexanone needed to achieve are fed back into the net after production, depend on the reaction conditions used in each case »

example 1

The following experiments illustrate the use of transition metal salts as catalysts in the co-oxidation of cyclohexane and n-butyraldehyde.

The reactor used consisted of a cylindrical glass container of 250 ml, which was equipped with rib

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like internals, a cruciform fiührer with a hollow shaft through which dry oxygen was introduced, an inlet pipe for the injection of aldehyde and a steam tube, which was with a water condenser and a Kuhlfinger filled with methanol / dry ice, of which liquid condensate in the Reactor was returned _o

1 mole of cyclohexane and the necessary amount of catalyst were used introduced into the reactor. This was dried with 22.8 l / at Oxygen flushed out while the cyclohexane was heated to the desired reaction temperature « While the flow of oxygen was maintained 1 mole of n-butyraldehyde for a time in the range of 177 slowly pressed into the reactor for up to 191 min. Sowing all of the aldehyde was depressed, the oxygen flow became continued for another 2 minutes.

The reaction products, including the substances condensed in the cold finger, were then dissolved in isopropanol and on n-butyraldehyde, 'cyclohexane, cyclohexanol, cyclohexanone, epsilon-caprolactone, adipic acid, glutaric acid » Succinic acid and n-butyric acid analyzed. The composition of the outflowing gas was determined with the help of mass

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spectrometry 'determined

The results obtained are shown in Table 1. Pie catalyst concentration is given as parts of catalysts tall, per Hillion parts of cyolohexane (ppm). "OgH ₁₂ - * oxidation products" means cyclohexanol, cyclohexanone, epsilon-oaprolaotone, adipic acid, glutaric acid and succinic acid. "Compounds X" means cyclohexanol, cyclohexanone, epailon-caprolactone and adipic acid. CL means epsilon-caprolaoton; AA means adipic acid. In all experiments, the conversion of n-butyraldehyde was 82 93 to 99 i> (auBser in Experiments 1 and H, where it was 87 and 89 $>), and the molar yield of n-butyric acid, based on isobutyraldehyde was consumed, up to 94 % (except in Example 1, where it was 65 % ). In the reaction products obtained in Examples 1 and H, no adipic acid could be found.

A comparison of the molar durosity yields of cyclohexane oxidation products and the molar ratios of Cyclohexane oxidation products to consumed aldehyde, the obtained in the experiments shows that these values increase with the catalyst concentration and that cobalt is the most effective catalyst. On the other hand, it falls

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• pellon- ^ aprolacton: adipic acid ratio with increasing Catalyst concentration. Chromium gives the highest level of reliability. Solve it so that a mixture aas in all measurements Cobalt and chromium compounds was the best catalyst.

Experiment 14 "in which no catalyst was used" is included for comparison.

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Table I.

ο
ο
Cu gate without Catal I. peat conc 4th Molar DureLt
aisle output ix
te an 0 / -H, ~ iolarcs Vsrc-
never from
Ir Π-.-Oxvdat i * FIi. \ _ .. ...
te on 7
fertilize Aua wfeUf'Moiarea V <sr — ίέοΧ
heir = | never lasts (
in-] £. "- Oaprolactonl idipic acid ions ail *. VeÄic
OL> AA Q) (η B.
φ
ex vobaltstea
advice
SI M 222 4th 6 12
Oxidation Pro
products {/>) 'j j-έ * ■
requirements train on ^C b ^H 12] 1.38 ₆ H _3? -Cxyda
proaukt8 T
2 ♦ 5-
48
Il It It I ₅ 4th 9.3 <ü _f 03.6
0.093 <2A
48 ■ 2 _? 26th 28 3 67 ! I H U ₅ 5 14.4 0.15? \ <■ - 1.52 36 4th 67 »» It 71 * 16 _? 5 0.173 O _p 75 33 5> 67 iangannaph
thenau i 21.7 0.227 5.00 23 6th 67 Jhromnaph *
fciienat 14, 4th 11.0 0.118 3.40 31 7th 67 fc.nadium * -
aaphthenate 15, 0 9.4 0.098 1.14 39 8th 70 Jickle
Laurate 14, 8th 13.1 . 0.140 1.83 36 9 70 iuthenium 14, 2 15.8 0.168 0.86 36 10 70 Citanstea
irat 15, 4)
8th} 12.9 0.138 2.98 45 11 70 Cobalt -
stearate <&
febenat 0,
3, .Si 10.4 ^ 0.112 3 _S 36 28 12th 70 41 13th 12.6 0.134 2.03 48 13th 70 - 15.6 0.165 \ 43 14th 67 3.0 0.033 GO 61 54 62 67 66 63 30th 82 84 26th

Example 2

According to the procedure of Example 1, 2 tests were carried out, which differed only in the duration, while the aldehyde was being pressed in »The reaction temperature was -0 ° C and the catalyst was cobalt stearate, accordingly 4 ppm cobalt metal, based on cyclohexane Acts are given in Table 2.

Tabel

Trial no.

Aldehydeindrückseit {mir.) Epsilon-Capro.lacton (g) obtained adipic acid (g)

Molar throughput of cyolohexane oxidation products +

Molar ratio of cyclohexane oxidation products -f aldehyde consumed

+ Molar yield of compounds X in relation to cyclohexane consumed {%)

Molar ratio epsilon-caprolactqn adipic acid

Molar ratio {%)

CL + AA

Cyolohexane oxidation products ⁺

+ The meanings of these expressions are in Example 1 specified.

I / IQ LI ^{new documents} (Art. 7, Paragraph 1, Paragraph 2, No. 1 _{, Clause 3 d «8} Amendment« * », v.4. F

ORIGINAL INSPECTED

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Example 3

8 moles of cyolohexane were euaamman with the catalyst used in each case in an aluminum-lined Introduced a reactor with a capacity of 3 liters, which was then filled with nitrogen to an Inen Brook of 28 atli. The content of the reactor was then kept to the desired reaction temperature, and a mixture of oxygen and nitrogen with 5? ol.-4l of oxygen was carried out at 1900 l / st the contents of the reactor «passed, while at the same time 2 Hol n-butyraldehyde per hour with the help of a Micropump were pushed into the reactor. The reactor pressure was automatically regulated to 2 atmospheres. The period of time for the addition of the aldehyde was 2 at Pushing in the aldehyde was bu end, the flow of the Oxygen / Stioketoif gas mixture continued for 5 min.

The reaction product was then cooled, if necessary made homogeneous by the addition of 1% propane oil and analyzed. The results obtained are shown in Table 3. The catalyst concentration is given in parts of catalyst metal per million parts of cyclohexane. ¹¹ CgH ₁ g oxidation products "means cyclohexanol, cyclohexanone, epsilon-caprolaoton, adipic acid, glutaric acid, succinic acid and

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BATH ORIGINAL

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n-Butyräureoyolohexylester, CL means epeilon-Caprolaoton and AA adipic acid,

In all experiments, the Tiarwandlung of n-butyraldehyde 93 to 96 i "and the molar Auebeute of n-Bottereäure 75-93 $> 9 was consumed with respect to butyraldehyde.

w The experimental results obtained show that Cyolo-

hexane in epeilon-Gaprolaoton and adipic acid even in the absence of a catalyst at temperatures of 75 ⁰ C and kooxydiert darftber, although a catalyst may be advantageous. Furthermore, the formation of epellon-Caprolaoton in the presence or absence of a catalyst passes through a maximum with increasing temperature, while the formation of adipic acid increases with increasing temperature.

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BATH ORIGINAL Table 3

t
S.
ι ο
ο Kataly
sator Catalysa-
; orconc. - - Passage
yield at Molar ratio
nis won
epsilon- Molar ratio
epsilon- Molar ratio
CL 4- AA O I. - - production production C ^ H. p-oxidation
Products Caprolactone
(S) Caprolaoton CgH-p-Oxyda-
tion prod. (^) S. 75 - - ten ($) consumed Al
dehyd Adipic acid 14th 17th 96 a - 3.6 0.08 3.6 4.6 27 18th 115 Chromnaph
thenat 3 * 6 7.2 0.15 12.8 2.6 25th 19th 137 W. 3.7 10.2 0.21 10.2 0.8 17th 20th 96 W. 69.7 12.4 0.26 4.5 0.3 38 21 116 Cobalt Naph
thenat 3.7 7.9 0.16 19.9 2.7 28 22nd 96 η 1.5 10.4 0.22 11.3 0.8 33 23 96 Cobalt naph
thenat &
Cnrotnnaph-
thenat 0.5)
3.7) 10.0 0.21 21.0 2.2 20th 24 116 12.3 0.26 14.8 2.1 20th 25th 96 14.7 0.31 15.1 1.3 23 26th 11.0 0.23 17.6 3.1

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Example 4

To illustrate the Wlederelnspelsung of cyclohexanol and cyclohexanone, a series of experiments was carried out according to the procedure of Example 1 at 70 ⁰ C, using a cobalt stearate / chromium naphthenate catalyst containing 1.6 ppm of cobalt and 3.5 ppm chromium, in relation on cyolohexane, was used. This encryption W search showed that 7 * J ^ Mol cyclohexanone was obtained Nettonuliproduktion of cyclohexanol and cyclohexanone in the Cyclohexanbeschickung at a content of 2.4 MOI $ cyclohexanol and 7, wherein the results of the reaction were as follows:

Conversion of butyraldehyde 96 % Conversion of the cyclohexane. 17.5 * Molar throughput of cyolohexane 14 % Oxidation products + Molar ratio of Cyolohexanoxyda- 0,

tion products +: spent aldehyde

Molar yield of compounds X +, based on 80% of cyclohexane consumed

Molar yield of epsilon-caprolactone 55 % Molar yield of adipic acid 20 %

+ The meanings of these terms are given in Example 1.

- 19-909805 / 1041

BATH ORIGINAL.

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- 19 - Example 5

1 mole of cyolohexane and cobalt stearate and also chromium anaphthenate, corresponding to 0 * 5 ppm cobalt and 3 «8 ppm chromium, in relation to cyclohexanes, were introduced into the reactor described in Example 1. Were Wäbrend a PIuB 22.8 1 oxygen / st maintained through the reactor and a reaction temperature of 70 ⁰ C, 1 mol Zsobutyraldehyd was continuously during imprinted a time of 183 minutes in the reactor. The reaction product was then analyzed according to the procedure of Example 1.

Conversion of Cyolohexane (£) 21.2 Product weight (g) Cyclohexanol 3 * 4 Cyclohexanone 5 Λ

epsllon-caprolaoton 4.0

Adipic acid 2.3

iBobutyric acid 62.3

Molar ratio Cyolohexane oxidation products

introduced aldehyde 0.143

-20-

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- 20 - Example 6

The procedure described in Example 5 was repeated, wherein however, freshly distilled benzaldehyde was used instead of isobutyraldehyde.

Conversion of the cyclohexane (Ji) 18.3 Product weight (g)

epsilon-caprolaoton 3 * 3

Adipic acid 0.5 Benzoic acid 8o, 5 Example 7

8 moles of cyclohexane, 672 g of acetone and cobalt (II) and chromium naphthenate, corresponding to 0.5 ppm of cobalt and 3.6 ppm of chromium, with respect to cyclohexane plus acetone, were introduced into an aluminum-lined reactor with a capacity of 3 l. By Reaktibnsteilnehmer I9OO l were / st of a mixture of oxygen and nitrogen with 5.1 vol Ji oxygen passed, the reactants were maintained at a temperature of 96 ⁰ C and under a pressure of 28 ATU. Over a period of 2 hours, 4 moles of acetaldehyde were continuously introduced into the reactor. The results of this experiment were

as follows:

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Conversion of the Cyclohexane Conversion of the Acetaldehyde Product weight (g)

Cyclohexanol Cyclohexanone

epsilon-caprolactone

Adipic acid Acetic acid

Molar throughput of Cyclohexanoxydatlonsprodukte

Molar ratio

Aldehyde consumed cyclohexane oxidation products

Molar ratio epsilon-caprolactone adipic acid

33.8 82

24.2 76.3

2.9 22.7 156.6

15.9 0.388

0.16

Patent claims:

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Claims (1)

1. A process for the preparation of adipic acid and / or £ -Caprolaoton a aldehydes at temperatures above 45 ⁰ C, characterized in that the aldehyde of the reaction is added portionwise continuously eye type or by oxidation in a liquid phase of cyclohexane with molecular oxygen in the presence of such that the molar ratio of aldehyde to cyolohexane in the reaction mixture during the reaction does not exceed 1:10, preferably not more than 1:50. 2. The method according to claim 1, characterized in that a temperature in the range from 75 to 135 ⁰ C, preferably from 95 to 115 ° C is used * 3 «Method according to one of the preceding claims, daduroh indicated that a catalyst is present, of a compound or compounds of at least θ ir em contains transition metal, 4ο method according to claim 3, characterized in that that the compound is a salt of an organic acid. 909805/1041 ORIGINAL BATHROOM 5. The method according to one of claims 3 or 4, characterized in that the transition metal cobalt, Manganese * tfiokel, vanadium, chromium, titanium or ruthenium 1st 6. The method according to claim 5, characterized in that the catalyst contains cobalt and chromium. 7. TtXfehren according to claim 6, characterized in that the catalyst contains predominantly chromium. β. Method naoh one of claims 3 to 7, characterized characterized in that the catalyst is in such an amount it is used that not more than 0.01% by weight of transition metal is present, based on oyolohexane. 9 · Method according to one of the claims 3 to 8, thereby it is indicated that the reaction temperature is at least 95 ° C. and the catalyst in such an amount it is used that not more than 0.0005 wt .- ^ transitions metal, beeogen on cyolohexane are present. 10 · NaOH method one of the claims 3 to 7, characterized in that the reaction temperature is below 7O ⁰ C and the catalyst used in such an amount 909805/1041 U68121 - 24 - becomes that no more a 0.1 wt .- ^ transition metal, based on cyolohexane, are present. 11. The method according to claim 10, characterized in that the catalyst is used in such an amount that O ₉ O00 I to 0.01 Qew .-,> TJbergnngemetall, referred to as Cyclonexan, are present. 12 · Method according to the preceding claims, daduroh characterized that the aldehyde is n-butyraldehyde is used. Method according to one of the preceding claims, daduroh characterized that cyclohexanone and cyclohexanol are fed back in such amounts that the net production of cyclohexanone and cyclohexanol is practically zero is. 909805/1041