DD294013A5 - PROCESS FOR THE PREPARATION OF 2-CYCLOHEXENYLCARBOXYLATES - Google Patents

Abstract

Process for the preparation of cyclohexen-2-yl carboxylates. The invention relates more particularly to a process for the preparation of a cyclohexen-2-yl carboxylate by cycloaddition of a 1,3-butadien-1-yl carboxylate and ethylene. Cyclohexen-2-yl carboxylates are useful intermediates in various organic syntheses.

Description

Field of application of the invention

The present invention relates to a process for the preparation of 2-cyclohexenylcarboxylates. The 2-cyclohexenylcarboxylates and especially the 2-cyclohexenylacetate are sought-after products as intermediates in various organic syntheses. So z. B. the 2-cyclohexenyl acetate for the preparation of 2-cyclohexenyl-1-ol be hydrolyzed. This product may also be dehydrogenated in a known manner to produce phenol, or dehydrated to cyclohexadiene, a useful intermediate for the preparation of monomers useful in the manufacture of polyesters or polyamides.

Characteristic of the known state of the art

It has also been proposed to prepare the 2-cyclohexenyl acetate by oxidation of the cyclohexenes in an acidic medium.

Thus, French Patent No. 1358707 discloses that this compound is obtained by oxidation of cyclohexene it:

Acetic anhydride is obtained by molecular oxygen in the presence of a catalyst based on cobalt and a bromide.

In U.S. Patent No. 3,632,633 it is proposed to prepare this compound by treating the cyclohexene with nitric acid in the presence of an acidic faujasite (a sodium-calcium-aluminosilicate).

In French Patent No. 2,202,226, the same ester is prepared by the reaction of cyclohexene, acetic acid and cyclohexyl hydroperoxide in the presence of cupric 2-chloride.

It is also known from Chem. Berichte 121, 1988, No. 6, pages 1151-1158, that this ester is also known by cycloaddition of 1-acetoxy-1,3-butadiene over one through a trimethylsilyl group such as (CHa ₃ SiCH = CHCOCl, substituted dienophile compound to form the unsaturated cyclic β-trimethylsilylcarboxylic acid, followed by hydrogenation of the latter to its saturated analog and decarboxylation-desilylation of the saturated acid to produce the desired ester.

While the 1-acotoxy-i, 3-butadiene is a readily available starting material by air oxidation of the butadiene in an acidic medium, the dienophiles substituted by a trimethylsilyl group are relatively rare and expensive derivatives. Moreover, the number of steps required to prepare the 2-cyclohexenyl acetate makes the development of such a process illusory in its industrial significance.

Although cyclohexene is an available starting material, it is only available in relatively limited quantities and at a relatively high price.

Object of the invention

The invention provides a process for the preparation of 2-cyclooxanylcarboxylic acid by cycloaddition of 1,3-butadienylcarboxylate and a readily available and relatively less expensive preparation, thus making it possible to carry out a variety of chemical reactions müsson. The research carried out by the Applicant has shown that it is possible to orosulfone diol by stopping 2-cyclohexenyl cerboxylates in one step by cycloaddition of i -butyl-carboxylate with ethylon.

Presentation of the invention The present invention is based on the object, a simplified process for the preparation of

2 provide cyclohexenylcarboxylates.

The present invention therefore has a process for the preparation of 2-cyclohexenyl carboxylates by cycloaddition

the subject of a 1,3-butadienylcarboxylate with ethylene.

Carboxylates are understood in the context of the present invention, the derivatives of carboxylic acids, the maximum

Containing 4 carbon atoms, and in particular the acetates.

The addition or condensation is accomplished by contacting ethylene and 1,3-butadionyl-carboxyl8t under el.iem Pressure greater than the atmospheric, and a temperature which is greater than or equal to 10O ⁰ C performed. For a favorable realization of the invention, the selected temperature is kept below 250 ⁹ C; because in practice

observed from this temperature, the decomposition of 1,3-butadienyl carboxylate. Preferably, it is between 12O ⁰ C and

The partial pressure of ethylene (measured at 25 ⁰ C) is generally greater than or equal to 5 bar (50OkPa); it is not advantageous

that it exceeds 200bar (2000OkPa). It is preferably between 30 and 70bar (3000 and 700OkPa).

According to a particularly advantageous process variant, the condensation in an organic solution or Diluent performed. For this purpose one can use different classes of organic compounds, in particular:

- Aromatic hydrocarbons, optionally chlorinated, such as. Benzene, toluene, the xylenes and orthodichlorobenzene;

- saturated aliphatic or cycloaliphatic hydrocarbons, such as. Cyclohexane, pentadecane and hexadecane;

- Esters such. Butyl acetate and isopracetyl acetate;

- Ether such. B. Diglyme (diethylene glycol dimethyl ether)

C'jfins, whose double bond is sterically hindered enough not to be useful as a dienophile over the 1,3-butadionylcarboxylate, e.g. dom 2,3-dimethyl-2-butene, to react.

The concentration of 1,3-butadienylcarboxylate in the organic solvent can vary within wide limits. If

is discontinuous and for a favorable operation of the process according to the invention, it is advantageous that it does not exceed 0.5 mol / l and good results are achieved at a concentration between 0.01 and 0.3 mol / l. It will be appreciated that when working semi-continuously or continuously, the 1,3-butadienyl-1-carboxylate may be added continuously to achieve a 2-cyclohexenyl-1-uarboxylate concentration of the order of 1 to 3 mol / l.

The presence of water in the reaction medium is tolerable, even at relatively high levels. One always observes one Secondary production of 2-cyclohexenol, itself a valuable product, therefore, the general conversion appears negative

to be influenced.

It may prove advantageous to carry out the condensation in the presence of a radical inhibitor, such as. B. hydroquinone or

4-Teniobutyl-pyrocatechol perform.

The amount of inhibitor needed for the reaction is not critical and is generally on the order of 0.5 to

10% by weight relative to 1,3-butadienylcarboxylate.

While the presence of an inert gas such. As argon or nitrogen in practice advantageous for a favorable flow of the Reaction, does not apply to oxygen or air, whose presence must be avoided. As has been shown previously in a specific case, the present invention also includes the production of

2-Cyclohexenyl acetate by cycloaddition of 1-acetoxy-i, 3-butadiene and ethylene.

The 1-acetoxy-1,3-butadiene is most readily available in the form of a mixture of trans and cis isomers. In the context of its work leading to the present invention, the Applicant has found that trans-isomers

of the 1-acetoxy-1,3-butadiene is more reactive than the cis isomer and results in better selectivity to the desired acetate.

Although the isomer mixture in the typical trans / cis ratio of the order of 1 to 1.5 according to the Behavior of the method according to the invention appears, it can be according to a more advantageous reaction variant of

present method achieved with trans-isomer enriched mixture.

The reaction time (or the residence time of the reactants) can vary widely and may vary slightly depending on

the desired conversion and the selected concrete conditions for the course of the reaction.

When working discontinuously, it is usually between 30 minutes and 30 hours. At the end of the reaction or a part of it, the 2-cyclohexenyl carboxylate is recovered

suitable agents, in particular by distillation.

The following examples illustrate the present invention. Autführungtbeliplel · Baispl "l1blt6 operation

In a 25 cm autoclave made of corrosion-resistant steel, ¹ part 10 cm 'of the organic solvent and 0.0984 g (0.879 mmol) of the i-acetoxy-butadiene / trans isomer ratio - 1.75) are added.

Close the autoclave and then fill it with 9bar ethylene (about 6.2 mmol) and then with 71 bar argon. The autoclave is then placed in an oven and left there for a period of 17 hours boi the specified temperature (T), the mixing is ensured by a shaking.

Thereafter, the autoclave is cooled and degassed and the reaction product analyzed by gas chromatography.

The selectivity for the 2-cyclohexenyl acetate S (AC) is indicated by the ratio to the converted 1-acotoxy-1,3-butndione.

The results as well as the particular reaction conditions are described in the following Table I.

Table I

at solvent T ⁰ C degree of conversion trans. selectivity game 12% S (AC) N ^e toluene 130 ice 19.5% 1 toluene 150 11% 30% 5.9% 2 toluene 170 14.5% 48.5% 12% 3 toluene 180 13.5% 20.5% 34% 4 cyclohexane 150 23.5% 38.5% 31% 5 cyclohexane 170 17% 13.5% 6 28% 19.5%

Example 7

In an existing stainless steel autoclave 10cm ¹ toluene and 0,115g (1,04mMol) i-acetoxy-IS-butadienltrans / cis isomer ratio = 1.56) in addition 4,6Gew .-% (based Priority of 25cm ³ content on the acetoxybutadiene) 4-t-butyl-pyrocatechol. Charge 70 bar of ethylene (about 48 mmol). The mixture is then heated for 3 hours at 180 ° C with a thorough mixing by shaking.

The following results are obtained:

Conversion degree of iscis isomer: 0

Conversion grade distrans isomers: 47%

Selectivity to the 2-acetoxycyclohexene: 93%

example

In an existing stainless steel, internally coated with Teflon autoclave are of 25cm 10cm ^{3 3} Table toluene, 0,115g (1,04mMol) 1-Aceto / .y-1,3-butadione (trans / cis ratio = 1, 56) and 4-t-butyl-pyrocatechol (4.6% by weight, based on acetoxybutadiene). Furthermore, one fills 40 bar of ethylene and 30 bar of argon. Subsequently, it is heated for β hours to 180 ° C.

The results obtained are as follows:

- degree of conversion of iscomers: 6%

- degree of conversion of the trans isomer: 48.5%

Selectivity to 2-acetoxycyclohexene: 72.5%

Examples 9 bl 17

It consists of several, made of corrosion-resistant steel and internally with Teflon * coated autoclave of 25cm ³ capacity.

In each autoclave is 10cm ³ solvent and a mmoles of 1-acetoxy-i, 3-butadiene (trans / cis-isomer ratio = 1.55) and 4,6Gew .-% of 4-Tertiobutyl-pyrocatechol. The autoclave are closed, then filled in each autoclave 40 bar of ethylene and 30bar argon.

The autoclave are each placed in an oven and then heated to 18O ⁰ C for 6 hours. The mixing is ensured by a Schiittelvorgang.

After cooling, each autoclave is degassed and then each reaction product is analyzed by gas chromatography. The results are shown in the following Table II.

Taballcll

at solvent degree of conversion trans selectivity game 48.5% S (AC) N " toluene ice 35% 9 butyl β% 48% 72.5% 10 cyclohexane 21.5% 69.5% 55.5% 11 pentadecane 13% 69.5% 53% 12 hexadecane 34% 56% 38% 13 Uiglyme 36.5% 99.5% 38.5% 14 acetic acid 21% 61% 49% 15 Oiglyme-water * 54% 93.5% without 16 without 81% 9.5% 17 92.5% 2.5%

Example · 18 to 20 It uses 3 corrosion resistant steel, inside with Teflon * coated autoclave with 25cm ³ content. In each autoclave are added 10 cm ^{1 of} toluene and various amounts of 1-acetoxy-i, 3-butadiene (trans / cis isomer ratio -

1.55), further 4.6% by weight of 4-tertio-butyl-pyrocatechol. The autoclaves are closed and then each autoclave is filled with 40 bar ethylene and 30 bar argon.

The autoclaves are each placed in an oven and then 6 hours. heated to 18O ⁰ C for a long time. The mixing

is ensured by a shaking process.

After cooling, each autoclave is degassed and then the reaction product by gas chromatography

analyzed. The results are shown in the following Table III.

Table III

In game 1-acetoxy- degree of conversion trans Selectivity S (AC) No. 1,3-butadiene ice 46.5% 48.5% 58.5% 18 19 20 0.207 mmol 1.03 mmol 5.21 mmol 4.5% 6% 24.5% 74% 72.5% 36%

Examples 21-22

Two stainless steel Teflon * coated autoclaves of 25cm ^{3 are used}

Content.

In each autoclave is added 10 cm ^{1 of} toluene, 1-acetoxy-1,4-butadiene (1.04 mmol, trans / cis isomer ratio = 1.55)

including 4,6% by weight of 4-t-butyl-pyrocatechol. The autoclaves are closed, then filled in each

Autoclave 50 bar argon and 10 bar ethylene. The autoclaves are each placed in an oven and then at the desired temperatures for 17 hours

heated. The mixing is ensured by a shaking.

After cooling, each autoclave is degassed and then each reaction product by gas chromatography

analyzed. The results are shown in the following Table IV:

Table IV

In game temperature degree of conversion trans Selectivity S (AC) No. ice 87% 99.5% 21 22 200 ⁰ C 230X 56% 79.5% 23.5% 17.5%

Examples 23-24

Two stainless steel autoclaves of 25 cm ³ content are used. In each autoclave is 10cm ³ of toluene and 0,11176g (1.05 mmol) of 1-acetoxy-i, 3-butadiene (trans / cis-isomer ratio

1.55). In one of the two autoclave is added in addition 4-t-butyl-pyrocatechol (3mol%, based on 1-acetoxy-butadiene) added.

Close the autoclave and then pour into each autoclave 40 bar of ethylene and 30 bar of argon. The autoclave are placed in an oven and then heated to 180X for β hours. The mixing is

ensured by a shaking.

After cooling, each autoclave is degassed and then each reaction product by gas chromatography

analyzed.

The results are shown in the following Table V:

Example no. 4-t-butyl degree of conversion trans Selectivity S (AC) pyrocatechol ice 48%, 9.5% 23 24 no 9% 17% 64% 49.5%

Example 25 Place in a stainless steel autoclave of 25cm ¹ volume 10cm 'toluene, 0,1173g

(1.047 mmol) 1-acetoxy-i, 3-butadiene (trans / cis isomer ratio <1.55) and 4-t-butylpyrocatechol (3 mol%, based on 1-acetoxybutadiene). 40 bar of ethylene and 30 bar of argon are introduced.

It is then heated for 30 hours at 180 ⁰ C. The results obtained are as follows:

- degree of conversion of cls-isomoron: 24%

- degree of conversion of the trans isomer: 95%

Selectivity to the 2-acetoxycyclohexene: 70.5%

Example 26 In an autoclave of 25 cm made of corrosion-resistant steel, ¹ part 10 cm ^{1 of} 2,3-dimethyl-2-butene;

0.115 g (1.04 mmol) of 1-acetoxy-1,3-butadiene (trans / cis ratio = 1.55) and 4-t-butylpyrocatochol (4.6 weight percent based on 1-acetoxy-butadiene). Then you fill 65bar ethylene and 55bar argon.

Thereafter, the mixture is heated for 3 hours at 180 ° C with constant mixing by shaking. The results obtained are as follows:

Conversion degree of iscis isomer: 34%

Conversion grade distrans isomers: 47.4%

Selectivity to 2-acetoxy-cyclohexene: 27%

Claims (13)

1. ancestor for the preparation of a 2-cyclohexonyl-carboxylate, characterized by cycloaddition of a 1,3-butadienyl-1-carboxylate and ethylene. 2. The method according to item 1, characterized in that the cycloaddition boi a pressure higher than the atmospheric and a temperature greater than or equal to 100 ⁰ C is performed. 3. The method according to item 2, characterized in that the temperature is less than 250 ⁰ C, 4. The method according to any one of the preceding points, characterized in that the partial pressure of ethylene, measured at 25 ⁰ C, greater than or equal to 5 bar (500 kPa). 5. The method according to any one of the preceding points, characterized in that the partial pressure of the ethylene, measured at 25 ⁰ C, between 30 and 70 bar (3000 and 700OkPa). 6. The method according to any one of the preceding points, characterized in that the cycloaddition is carried out in an organic solvent. 7. The method of item 6, characterized in that the solvent among the aromatic, optionally chlorinated hydrocarbons; the aliphatic or cycloaliphatic saturated hydrocarbons, the esters, the ethers and the olefins whose double bond is sterically hindered enough to not react as a dienophile with the 1,3-butadienyl-1 carboxylate is selected. 8. The method according to any one of the items 6 or 7, characterized in that the concentration of 1,3-butadiene-1-carboxylates is less than or equal to 0.5 moles per liter. 9. The method according to any one of the preceding points, characterized in that the cycloaddition is carried out under an inert gas. 10. The method according to any one of the preceding points, characterized in that the cycloaddition is carried out in the presence of a radical inhibitor. 11. A process according to any one of the preceding points, characterized in that the 1,3-butadienyl-1-carboxylate is 1-acetoxy-1,3-butadiene. 12. The method according to item 11, characterized in that the 1-acetoxy-i, 3-butadiene is obtained as a predominantly trans isomers-containing cis / trans isomer mixture. 13. The method according to any one of the preceding points, characterized in that the reaction temperature between 12O ⁰ C and 23O ⁰ C.