DE2155151A1 - Process for the production of epoxies - Google Patents

Description

In US Pat. No. 3,350,422, the epoxidation of Described olefins with hydroperoxides in the presence of various metal catalysts including molybdenum. Various hydroperoxides are mentioned here, among which are methylcyclohexene hydroperoxide and phenylcyclohexane hydroperoxide Find. Both are tertiary hydroperoxides and are characterized by high stability. You can easily getting produced.

Cyclohexalhydroperoxide is, however, a compound in which the hydroperoxide group is on a secondary carbon atom adheres, so that this compound is less stable than the tertiary hydroperoxides. Furthermore is cyclohexal hydroperoxide considerably more difficult to produce than the tertiary hydroperoxides, because of the oxidation of cyclohexane with molecular Oxygen in general only very small amounts of the hydroperoxide with the formation of relatively large amounts of the alcohol, of ketone and acids such as adipic acid.

In the literature it has already been suggested that a high selectivity, i.e. about $ 50, of cyclohexyl hydroperoxide in that To obtain oxidation product by the fact that the oxidation is only down to a very low conversion, i.e. less than around $ 2, and with a slow conversion speed undertakes. However, it can be shown that the cyclohexyl

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hydroperoxide with high degrees of conversion, i.e. about and high conversion rates can, if the oxidation with molecular oxygen practically in the absence of heavy metal ions, which cause the decomposition of the Hydroperoxide would catalyze, and carried out in the presence of a tertiary alcohol and a tertiary hydroperoxide will. This discovery makes the production of cyclohexyl hydroperoxide technically interesting.

One of the disadvantages of using a secondary hydroper " Oxyds such as cyclohexyl hydroperoxide is that this substance is not a particularly effective oxidizing agent in the above Molybdenum-catalyzed olefin epoxidation mentioned is. In general, the yields of the Bpoxide are, in particular in the case of CX olefins, relatively poor, so that secondary hydroperoxides are used in the aforementioned olefin epoxidation process have not yet been considered particularly suitable.

However, it is desirable to use such a method as Oxidant Cyclohexylhydroperoxyd wherein, as the hydroperoxide to cyclohexanol is reduced, which can be oxidized to phenol h denitie_ ££ or cyclohexanone. Cyclohexanone is known to be a starting material for the production of lysine, caprolactone, adipic acid and caprolactam. Naturally, these compounds are particularly interesting for the production of nylon fibers.

Since pure cyclohexyl hydroperoxide is not a particularly good oxidation catalyst for the epoxidation reaction, it was assumed that an oxidation product, which in its manufacture in the case of the oxidation of cyclohexane with molecular oxygen, the result is far less Usefulness would be because there would be large amounts of by-products. The separation of the by-products from the cyclohexyl hydroperoxide but brings quite serious difficulties-

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problems because the hydroperoxide is unstable. Even so, the crude cyclohexane oxidation product is an important one potential value as the cyclohexyl hydroperoxide is reduced to cyclohexanol in the epoxidation reaction and because the latter connection is valuable.

It has been found that when the crude oxidation product is used after drying in the epoxidation of olefins such as octene-1 and octene-2 get surprisingly good results became. The presence of cyclohexanol in the oxidation product thus not only did not bring about any adverse effects for the reaction with itself, but actually resulted in a completely surprising improvement.

According to the invention, a method for the preparation of epoxides is now provided wherein an olefinic compound, at temperatures ranging from 80 to 150 ⁰ C in the presence of a molybdenum-containing catalyst is contacted with an oxidation product into contact, represented by the non-catalytic Oxidation of cyclohexane with molecular oxygen is obtained. As a further development and improvement of the process according to the invention, a tertiary alcohol such as tertiary butyl alcohol is used together with the oxidation product during the epoxidation reaction.

The process of the invention is applicable to all compounds which contain one or more olefinic double bonds. Thus, any olefins can be epoxidized by the process of the invention, their epoxidation with a molybdenum-containing catalyst and an organic hydroperoxide as oxidizing agent previously described has been. The olefinic compounds can be OC-olefins (terminal olefins) or internal olefins can be both branched and straight-chain, as well as cycloaliphatic olefins. It can also be mono, di and

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Polyolefins are epoxidized, as well as the substituted compounds such as allyl alcohol, methallyl alcohol, allyl chloride, unsaturated long-chain alcohols and the like.

The molybdenum catalysts that can be used are molybdenum compounds as described in the patent literature, for example in U.S. Patents 3,434,975, 3,453,218 and 3,480,563. In general, it has been found that any molybdenum compounds, both inorganic and organic compounds as catalysts can be used in this process.

The crude cyclohexane oxidate is that produced by non-catalytic Oxidation of cyclohexane with molecular oxygen is obtained, i.e. the oxidation is practically in In the absence of metal ions, which - if they were present - cause the decomposition of the cyclohexane oxidation product would cause. The oxidation product can be prepared according to the known, described processes, in which approximately a selectivity of 50 mol $ to the hydroperoxide is obtained by having a low degree of conversion, i.e. $ 1.5 to $ 2, and operate at a correspondingly low conversion rate. The oxidation mixture is preferably prepared by the method described above, in which the oxidation with molecular Oxygen in the presence of a tertiary alcohol such as tertiary butyl alcohol in an amount of, for example 10% by weight, based on the added cyclohexane, and in the presence of a tertiary hydroperoxide such as tertiary butyl hydroperoxide in a relatively small amount, for example a molar ratio of hydroperoxide to cyclohexane of about 0.1: 1. In general, the amount of cyclohexyl hydroperoxide in the oxidation product ranges from about 45 mole # to about 80 mole # with the remainder generally relatively uniformly composed of unreacted cyclohexane, cyclohexanol and cyclohexanone together with a residue

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acidic compounds, water and the like. Consists. Farther can if tertiary butyl alcohol and tertiary butyl hydroperoxide have been used in the oxidation stage, these substances are left in the oxidation product, since they the Do not adversely affect the use of the oxidation product as an oxidizing agent during epoxidation. The tertiary Butyl hydroperoxide itself functions naturally as an oxidizing agent and even in very small amounts.

The Epoxydierungsprodeß is durchgsführt at temperatures in the range of about 80 to 150 ⁰ C and at pressures that are only sufficient to maintain the reactants in the liquid phase at the respective reaction temperatures. Pressures can range up to 70.3 atmospheres (1000 psig). For example, if propylene is to be epoxidized as an olefin, the preferred temperature range is about 90 to HO ⁰ C, with pressures extending from about 35.2 to 56.2 atmospheres (500 to 800 psig). In general, catalyst concentrations between 20 and 10X ppm molybdenum, based on the weight of the olefin-free liquid in the reaction, are suitable for carrying out the reaction, with concentrations ranging from 50 to 800 ppm molybdenum (wt.), Based on the weight of the olefin-free liquid , to be favoured. Although 1 mole of olefin per 1 mole of hydroperoxide is stoichiometrically for the epoxidation reaction, it is preferred to work with an excess of the olefin in order to ensure a high conversion of the hydroperoxide. In general, the molar ratios of olefin to hydroperoxide can range from 1: 1 to 10: 1 or higher, with molar ratios of about 1.5: 1 to 7: 1 being preferred.

In one embodiment of the invention in which a tertiary Alcohol is added to the reaction mixture, e.g. in the epoxidation of CX -olefins, especially in those which have 3 to 20 carbon atoms in the molecule, the molar ratio of alcohol to .Hydroperoxide is preferably in the

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ranging from 1: 1 to 6: 1, with molar ratios from 1: 1 to 3: 1 are more preferred. Most preferred as the tertiary alcohol is tertiary butyl alcohol.

The invention is illustrated in the examples. Molybdenum hexacarbonyl was used as the catalyst in all examples because this compound is readily available and because it was desirable to make comparisons that were as closely related as possible. Naturally, any compound known for known epoxidation processes can be used as the molybdenum catalyst.

example 1

A sample of 47% by weight cyclohexyl hydroperoxide, 18% by weight cyclohexanol, 16% by weight cyclohexanone and 19% by weight cyclohexane was dried overnight over anhydrous magnesium sulfate and used for the epoxidation reaction. The tests were carried out by placing 5 ml of a solution prepared from 10 g of the 47% cyclohexyl hydroperoxide solution, 15 g of 1-octene or 2-octene and 0.02 g of Mo (CO) g in a closed tube as shown in Table I times shown were heated ^{to 90 0 C.}

Olefin Table I. Conversion ^ '
Weight # (2)
Epoxy yield ^{v J}
Weight $ attempt
No. Octene-1 Time
Min. 65 59 1 Octene-1 30th 88 58 2 Octene-2 60 100 91 3 Octene-2 30th 100 91 4th 60

Footnotes:

(1) Conversion of the hydroperoxide expressed in wt on the amount added.

(2) Based on the converted hydroperoxide.

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The results in Table I show a 58% for octene-1 1,2-epoxy octane yield at 65 and 88 conversions. For the more active olefin, octene-2, however, the 2,3-epoxyoctane yield is $ 91 for a 100 # conversion of hydroperoxide.

Example 2

To improve the conversion and the yield of the% oxide Trying to get out of the CX olefin became the epoxidation mixture a tertiary alcohol added. The tests were carried out identically as in Example 1. at the addition of 2 moles of tertiary butyl alcohol for every mole of cyclohexyl hydroperoxide increased the yield to $ 83 at one 91% conversion as shown in Table II.

Olefin Tabel II Conversion Epoxy coating attempt Additive Time lung ζ ₁ ^ booty / pN
Weight V ' No. Octene-1 Min. 91 80 5 Octene-1 t-butyl alcohol 60 95 75 6th Octene-1 t-butyl alcohol 90 79 84 7th Octene-1 t-butyl alcohol 60 91 83 8th Octene-1 t-butyl alcohol 90 91 75 9 Octene-1 Cyclohexanol 30th 96 71 10 Cyclohexanol 60

Footnotes:

(1) Weight > conversion of the hydroperoxide, based on the amount added.

(2) Based on the converted hydroperoxide.

Experiments 5 and 6: 0.03 g Mo (CO) _{6 was} used instead of 0.02 g

used.

Experiments 7 and 8: 6 moles of tertiary butyl alcohol per mole of hydroperoxide

Experiments 9 and 10: 2 moles of cyclohexanol per mole of hydroperoxide.

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The larger amounts of the tertiary alcohol in Runs 7 and 8 give slightly higher yields, but the rate of the reaction will be is slowed down considerably, so it requires a 50% longer period of time to do the same conversion achieve, but the yield is only increased by 3%.

The data also show that the presence of cyclohexanol is beneficial is, as more amounts of this alcohol are added as in Runs 9 and 10, improvements in conversion from 88% by weight to 96% by weight and the yield of 58% by weight 71% by weight brought with it. Thus, if desired, that can unreacted cyclohexyl hydroperoxide and cyclohexanol along with the other by-products and the catalyst after the separation of the olefin epoxide in the ^ eaktionsζone together be recycled with fresh cyclohexane oxidation product in order to come into contact with further olefin.

Example 3

These experiments were carried out using a sample of the oxidation product carried out, the 52.5% cyclohexyl hydroperoxide, 19.5 $ cyclohexane, 17.9% cyclohexanol and cyclohexanone, 7.3% Methanol and 3% water. This sample was before the Use over anhydrous MgSO. dried. The experiments were carried out by using a solution of various amounts of liquefied propylene, 50 g of the dry cyclohexyl hydroperoxide oxidation product, different amounts of tertiary butyl alcohol and different amounts of Mo (CO) g catalyst heated in a 500 ml autoclave that was magnetically stirred at various temperatures and times became. The reactor was cooled to room temperature after each experiment. The gaseous products were in a Dry ice acetone trap collected. The liquids were in collected in a water trap. The products were after standard iodometric titration for hydroperoxide analyzed. The epoxy was determined by gas chromatography Analysis determined. The results obtained are summarized in .Table III »

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Table III

Attempt additive, g

Propylene Mo (CO) g Temp., 0 time Conversion Epoxy Ausml. g Min. wt.% (i) booty, wt. % (2)

11 M 15 H 15

t-butyl alcohol,

t-butyl alcohol,

Isopropanol,

t-butyl alcohol,

t-butyl alcohol,

100 100 100 100 200

0.20 120-125 50

0.20 110-116 50

0.15 110-116 50

0.08 100-105 50

0.10 100-105 60

100

100

100

78

88

Footnotesί

(1) Conversion of the hydroperoxide expressed in% by weight, based on the amount added.

(2) Based on the converted hydroperoxide

It can be seen that with a large excess of propylene the best combination of conversion and yield is obtained under mild conditions and one hour.

Example 4

Further tests were carried out with a sample containing 18.5 $ cyclohexyl hydroperoxide, 10 $ cyclohexanone, 12.5 $ cyclohexanol, 47.2 $ cyclohexane, 2.7 $ acids (as adipic acid) and 0.7 $ water, with the fiest was not identified. The results obtained are shown in Table IV. This experiment was carried out at a temperature of 100 ^° C. and a reaction time of one hour.

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Table IV

attempt
No. Cyclohexyl
hydroperoxide
oxidation prod. Footnotes: Propylene
ml Additive, g 50 Mo (CO) ₆ conversion Epoxy yield
% By weight (2) 16 100 200 t-butyl alcohol, 50 0.08 100 84 17th 100 200 Cyclohexane, 0.08 100 54 18th 100 300 0.06 100 60 19th 125 200 0.08 100 66 NJ
O
CD
CD

(1) Conversion of the hydroperoxide expressed in wt
on the amount added.

(2) Based on the converted hydroperoxide

* The sample of the oxidation product was treated _{with a Ha 2 CO, solution}
and washed with water to eliminate the acids.

The values of the individual examples show the following: (1) that neither cyclohexanol nor cyclohexanone hinder the epoxidation reaction, (2) that small amounts of acids reduce the epoxy yield does not seem to affect to a great extent

(3) that the addition of a tertiary alcohol, in particular t-butyl alcohol, improves the yields,

(4) that an excess of propylene in the absence of t-butyl alcohol does not improve the yield and that (5) the cyclohexane oxidation product can have a hydroperoxide content as low as 15% by weight and that it can be used successfully can be, taking oxidation products with $ 50 or more are also satisfactory.

It was also found that low 'amounts of water and Amounts of acid can be tolerated, but better results are obtained if one uses neutral, anhydrous Conditions works.

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Claims (9)

Claims A process for the preparation of epoxides in which olefinic compound "is placed at temperatures ranging from 80 to 150 ⁰ C in the presence of a molybdenum-containing catalyst with a Cyclohexanoxydationsprodukt in contact, characterized in that there is used as Cyclohexanoxydationsprodukt the oxidation product obtained by non- catalytic oxidation of cyclohexane with molecular oxygen is obtained. 2. The method according to claim 1, characterized in that the oxidation product comprises cyclohexyl hydroperoxide, cyclohexanone, cyclohexanol, unconverted cyclohexane and smaller amounts of other oxidation products. 3. The method according to claim 2, characterized in that the cyclohexyl hydroperoxide is present in amounts of at least 15 wt. ^ S, based on the weight of the oxidation product. 4. The method according to claim 1, characterized in that the olefinic compound is a CX -olefin having 3 to 20 carbon atoms and that the upoxidation is carried out in the presence of a tertiary alcohol. 5. The method according to claim 4, characterized in that the CX-olefin is propylene or octene-1 and that the tertiary alcohol is tertiary butyl alcohol. 6. The method according to claim 1, characterized in that the olefinic compound is propylene and that the epoxidation reaction is carried out in the presence of added cyclohexanol. 209840/1120 7. The method according to claim 6, characterized in that the added cyclohexanol is obtained from the reaction products of the epoxidation reaction from which the epoxidation product has been separated off. 8. The method according to any one of claims 1 to 5, characterized in that the cyclohexane oxidation product is obtained by non-catalytic oxidation of cyclohexane with molecular oxygen in the presence of a tertiary alcohol and a tertiary hydroperoxide. 9. The method according to claim 8, characterized in that the tertiary alcohol is tertiary 3utyl alcohol and that the tertiary hydroperoxide is tertiary butyl hydroperoxide. 209840/1120