JP2002536351A - Method for producing 3-alkenoic acid ester and catalyst for performing the method - Google Patents

Abstract

(57) [Summary] The present invention provides a compound represented by the general reaction formula (I): [Wherein R ₁ -R ₆ are each independently hydrogen or C ₁ -C ₃₀ -alkyl, C ₆ -C ₃₀ -aryl, C ₇ -C ₃₀ -alkylaryl, C ₅ -C ₁₂ -cycloalkyl Or C ₁ -C ₂₁ -alkyl-C ₆ -C ₉ -cycloalkyl and R ₇ represents a C ₁ -C ₃₀ -alkyl group] in the presence of CO by at least 10 bar (1 MPa). in pressure, Pd-compound and one or more MCl n _- type compounds [wherein, M has one of the meanings of the following: n = 2 when the alkaline earth metal ions, group 4 if n = 4, A metal ion of (IV subgroup), a metal ion of group 6 (VI subgroup when n = 3, 5 or 6) in the absence of an organic base containing phosphorus or nitrogen. Attach mate to diene To a process for the selective production of 3-alkenoic acid esters.

Description

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a method for producing a 3-alkenoic acid ester by a catalytic reaction between a diene and an alkyl formate. The invention further relates to a catalyst which is particularly suitable for the process.

[0002] 3-Alkenic esters are versatile available intermediate products. From 3-pentenoate, for example, adipic ester or 6-oxohexanoate is produced. These materials are nylon-6 or nylon 6,6.
Used as an intermediate in the production of

From DE-B-3040432 (US Pat. No. 4,332,966), at least two
A process for the preparation of 3-alkenoic esters by catalytically carbonylating a diene with carbon monoxide (CO) and an alcohol, based on a cobalt carbonyl catalyst dissolved in a solvent consisting of two N-heterocycles. It is known. The use of solvents requires expensive separation steps. In addition, relatively high pressures (300 ba
r).

[0004] US Pat. No. 5,495,041 relates to a similar process for the preparation of pentenoic acid esters, in which a catalyst consisting of palladium, pentenoic acid and a phosphine derivative is used. Disadvantages of this method are low selectivity and relatively high catalyst usage.

[0005] WO 97/29069 describes the following reaction sequence:

[0006]

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Discloses a method based on

This method is based on the use of a palladium catalyst which is unstable in alcohol or water. WO 97/29069 mentions the molar ratio of alcohol to pentenoic acid chloride, in which the decomposition of the Pd-catalyst is not important, but nevertheless the acid chloride is essentially completely compatible with the ester Has been converted to. Retention of these ratios can only be achieved in practice by expensive multi-step reaction methods. In contrast, in the case of a single reaction step, it is difficult to maintain this ratio. This is because the acid chloride is simply formed as an intermediate. If a shortage of alcohol is added, the reactive acid chloride accumulates in the reaction mixture and, as described in WO 97/29069,
Very difficult to separate. Furthermore, the adjustment of the defined HCl concentration and the handling of HCl have further problems. Furthermore, the chlorinated intermediate products must be separated from the reaction mixture in each case, which makes the process more expensive.

JP-A 81113242 discloses the addition of methyl formate to butadiene in isoquinoline or other comparable solvents under the catalysis of a cobalt carbonyl complex in a CO atmosphere at 300 bar and 120 ° C. . The problem with this method is firstly the use of solvents which have to be separated from the product in an expensive separation step. The selectivity of this method is moderate and a mixture of pentenoic acid and pentenoate is formed. Nevertheless, high CO partial pressures are required and relatively large amounts of catalyst must be provided.

[0010] Keim and Becker (Journal of Molecular Catalysis 54, 1989, 9
Pp 5-101) may be performed in the presence of PdCl ₂ and HCl, describes the addition of a methyl formate butadiene. Keim and Becker only achieve unsatisfactory yields of 10-15% of pentenoates at a CO pressure of 80 bar. With this catalyst system, only moderate selectivities have been achieved. further,
Again, handling and recycling of HCl is very problematic.

The object of the present invention is therefore to be able to be carried out solvent-free, in which the starting material functions exclusively as a solvent, whereby the addition of HCl is unnecessary and has a higher selectivity than known processes. An object of the present invention is to provide a method for producing 3-alkenoic acid esters.

Furthermore, the method should be able to be performed at lower pressures than previously known methods.

An object of the present invention is to provide a compound represented by the general reaction formula I

[0014]

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[Wherein, R _{1 to} R ₆ independently represent hydrogen or C ₁ -C ₃₀ -alkyl, C ₆ -C ₃₀ -aryl, C ₇ -C ₃₀ -alkylaryl, C ₅ -C ₁₂ -Cycloalkyl or C ₁ -C ₂₁ -alkyl-C ₆ -C ₉ -cycloalkyl, and R ₇ represents a C ₁ -C ₃₀ -alkyl group] in the presence of CO at least 10 bar (1 MPa) A) a Pd-compound and b) one or more compounds of the type MCl _n , wherein M is a compound of the formula (3) wherein the alkylformate is added to the diene at a partial pressure of Has one of the following meanings:-alkaline earth metal ion when n = 2-group 4 metal ion when n = 4 (IV subgroup)-group 6 metal when n = 3, 5 or 6 On (VI sub-group)], in the absence of a phosphorus or nitrogen-containing organic base. Was.

Further, the present invention provides a catalyst for performing the method of the present invention.

The catalyst comprises: a) a Pd compound and b) one or more compounds of the MCl _n type, wherein M has one of the following meanings: if n = 2, alkaline earth metal ions When -n = 4, it contains a metal ion of group 4 (IV subgroup). When n = 3, 5, or 6, it contains a metal ion of group 6 (VI subgroup).

R _{1 to} R ₆ advantageously represent hydrogen or methyl. R ₇ is preferably an unbranched C ₁ -C ₁₂ -alkyl group, in particular an unbranched C ₁ -C ₆ -alkyl group, for example methyl, ethyl, n-propyl, n-butyl.

The CO required to build the CO-Stuetzdruck is provided by the decomposition of the alkyl formate, for example methyl formate. Because,
The minimum required CO partial pressure is very low at 10 bar (1 MPa). 1
Preference is given to a CO partial pressure of 0 to 150 bar, preferably 15 to 100 bar.

The alkyl formate which can be used according to the invention can be obtained on a large scale by carbonylation of alcohols and can be transported to the point of use less expensively than CO. Methyl formate can also be obtained in high yields directly from methanol (see Applied Catalysis 57, 1990, pp. 1-30).

The process of the invention can be made without additional inert solvents. That is, the starting materials shown in I function similarly as solvents. Due to the relatively high volatility of the alkyl formates, there is a cost advantage compared to the work-up in processes where the corresponding alcohols or other solvents are used.

The catalyst of the present invention contains a palladium compound, particularly a Pd salt. Advantageously ^{Pd I I} salts, in particular ^{Pd II} halides, in particular the ^{Pd II} chloride, for example, using a PdCl ₂ or PdCl _{2 (PhCN) 2} or Na ₂ [PdCl _4].

The catalyst according to the invention further comprises MCl_nCompounds of this type or various of this type
A mixture consisting of the following compounds: M is an alkaline earth metal ion such as M
g²⁺, Ca²⁺, Sr²⁺And Ba²⁺In this case, Mg²⁺ , Ca²⁺Is particularly advantageous. Similarly, M may be a Group 4 metal ion (
Also referred to as the IV sub-tribe. Nomenklatur der Anorganischen Chemie, VCH Wei
nheim, ISBN 3-527-29340). Group 4 includes Ti⁴⁺, Zr⁴⁺And Hf
⁴⁺Belong, and at that time, Ti⁴⁺Is advantageous. M is a group 6 metal ion,
(Formerly VI subfamily). This metal includes Cr, Mo and W. The gold
The genus has, within the scope of the present invention, an oxidation number III, IV or VI,^VHas
It is profitable.

[0024] Nitrogen or phosphorus-containing basic organic compounds such as triphenylphosphine (
PPh3) is frequently used as a cocatalyst. This is based on the fact that the addition of such compounds significantly inhibits the process according to the invention and should therefore be avoided (see Comparative Example 16).

In carrying out the process, the following molar ratios are preferably used: The ratio of palladium to MCn _n advantageously corresponds to 1/1 to 1/100, in particular 1/3 to 1/30. The ratio of diene to palladium is advantageously between 1/1 and 1/10000, in particular between 1/20 and 1 /
000. The ratio of palladium to alkyl formate is advantageously between 1/100 and
Advantageously it is between 1/10000, in particular between 1/1000 and 1/5000.
This ratio is adjusted before the start of the reaction in the case of a discontinuous reaction process. In the case of a continuous reaction method, these molar ratios are preferably adjusted in a static state. The reaction temperature is usually in the range of 60 to 120C.

The method according to the invention has an improved selectivity over known methods. further,
There is no need to use HCl as a promoter. This eliminates handling problems associated with HCl. On the other hand, HCl does not inhibit the method of the present invention symmetrically with the above-mentioned organic bases containing nitrogen or phosphorus.

In another embodiment of the present invention, the catalyst further contains CuCl ₂ or FeCl ₃ . The molar ratio of palladium to CuCl ₂ or FeCl ₃ is advantageously 1
/ 1 to 1/200, especially 1/5 to 1/50.

[0028] In a further embodiment, the method can be performed without the introduction of HCl.

In another embodiment of the present invention, R _{1 to} R ₆ are each hydrogen. Therefore, butadiene is used as a starting material.

In another aspect of the invention, R ₁ is methyl and R ₂ -R ₆ are each hydrogen. Thus, isoprene is used as a starting material.

In another embodiment of the present invention, R ₇ is methyl, ethyl, propyl or butyl. These alkyl groups are advantageously unbranched. The use of methyl formate as starting material is particularly advantageous.

The catalyst does not contain a basic organic compound containing nitrogen or phosphorus, for example, triphenylphosphine. These will generally adversely affect their activity.

[0033] The catalyst of the present invention, various compounds of MCl _n-type, advantageously of less than 3, in particular can contain of less than two. The total number of the various chloride salts contained in the catalyst is advantageously less than 5, especially less than 4.

MCl_nCompounds of the type may be in the form of adducts that are easy to handle, for example TiCl ₄ (HCO₂CH₃)₂, ZrCl₄(HCO₂CH₃)₂Or HfCl₄(
HCO₂CH₃)₂Can be used in the form of

[0035] In another embodiment of the catalyst of the present invention, the metal ion is ^{+ Hf 4+} or ^{Mo 5.}

[0036] In another embodiment of the catalyst of the present invention,₂And other MCl_nThailand
Compound (where M is Ti⁴⁺, Zr⁴⁺Or Hf⁴⁺Is included)
You. Thus, the resulting catalyst is, for example, PdCl₂, MgCl₂And salt TiCl ₄ , ZrCl₄Or HfCl₄Containing one of the following.

In another embodiment of the catalyst according to the invention, it additionally contains CuCl ₂ .

In another embodiment of the catalyst containing CuCl ₂ of the present invention, M is Mg ^{2 +} , Ti ⁴⁺ , Zr ⁴⁺ or Hf ⁴⁺ . Thus, the catalyst is, for example, PdC
_{l 2 / CuCl 2 / MgCl 2} ; PdCl 2 / CuCl 2 / TiCl 4; PdC
l is ₂ / CuCl ₂ / ZrCl ₄ or _{PdCl 2 / CuCl 2 / HfCl 4} .

In another embodiment of the catalyst according to the invention, it additionally contains FeCl ₃ .

The present invention will be described in detail below by way of examples.

EXAMPLES General Methods for Performing the Test The test was carried out in a 25 ml glass autoclave up to 15 bar and at relatively high pressure in a 250 ml stainless steel autoclave with a glass insert.

Under a protective gas, the autoclave was charged with the amounts of PdCl ₂ , additives, methyl formate (MeFo), diene and decalin 0.1 ml as standard in the autoclave. The desired reaction pressure was subsequently adjusted with CO and the reaction mixture was brought to the stated temperature. After the indicated reaction time, the reactor was cooled and vented. The reaction output was analyzed by gas chromatography (GC) to determine its composition.

After the reaction temperature was reached, the reaction pressure was kept constant. In a test in which MeFo was added to butadiene, the composition of the reaction gas was investigated by GC analysis. The CO content at the end of the reaction is generally 78% (butadiene = 9%, MeFo = 11%, C
O ₂ = 1%, CH ₄ = 0.2%, H ₂ = 0.2%). A gas analysis sample was removed after cooling the reaction mixture. At that time, the gas was depressurized to atmospheric pressure.
Percentages are based on moles (mol%).

The test results are summarized in the table.

Comparative Examples 1 and 2 show that using PdCl ₂ as the sole catalyst can obtain significant amounts of the desired product only in the presence of relatively large amounts of alcohol. However, the yields and selectivities are significantly lower than those of the examples according to the invention.

Comparison of Comparative Examples 7 and 9 with Example 8 according to the invention shows that the catalyst of the invention is HCl
Shows that to be able to achieve a relatively high yield and selectivity than known associations composed of PdCl ₂ Metropolitan.

Examples 13 and 14 show that the alcohol corresponding to the formate (here methanol, Me
Figure 2 shows the effect of OH) on the activity of the catalyst according to the invention: it does not inhibit even small amounts as present in commercially available alkyl formates, but relatively high amounts of alcohol have an inhibitory effect. . Comparative Example 15 shows that the catalyst of the present invention does not have the effect of diene carbonylation, as would be expected when MeOH was redissolved into MeOH and CO.

Comparative Example 16 clearly shows the inhibitory effect of a nitrogen or phosphorus containing basic organic compound.

[0049]

[Table 1]

[0050]

[Table 2]

P: total pressure at reaction temperature (bar) T: reaction temperature (° C.) t: reaction temperature (hour) Formate: amount of formate charged in the reactor Molar ratio: molar ratio of Pd / diene 3-Alkenoic ester Y [%]: Yield of 3-alkenoic ester 3-Alkenoic ester S [%]: Selectivity for 3-alkenoic ester ¹ ): Main product is vinylcyclohexane ² ): Main A good by-product is vinylcyclohexane.

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (reference) // C07B 61/00 300 C07B 61/00 300 (72) Inventor Helmut Werner Germany Würzburg Geo Würzburg −Strasse 1 (72) Inventor Martin Schaefer Germany Ludwigshafen Luitpoldstrasse 65 (72) Inventor Michael Schulz Germany Ludwigshalfen Downer Strasse 39 F-term (reference) 4G069 AA02 AA06 BB08A BB08B BC10A BC10B BC31A BC31B BC50A BC50B BC52A BC52B BC59A BC59B BC66A BC66B BC72A BC72B BD12A BD12B CB75 DA02 DA03 4H006 AA02 AB84 AC21 AC27 BA05 BA06 BA10 BA14 BA19 BA37 KA34 4H039 CA66 CF10 CJ90

Claims (11)

[Claims] 1. General reaction formula I Wherein R ₁ -R ₆ are independently hydrogen or C ₁ -C ₃₀ -alkyl, C ₆ -C ₃₀ -aryl, C ₇ -C ₃₀ -alkylaryl, C ₅ -C ₁₂ -cycloalkyl Or C ₁ -C ₂₁ -alkyl-C ₆ -C ₉ -cycloalkyl and R ₇ represents a C ₁ -C ₃₀ -alkyl group] in the presence of CO by at least 10 bar (1 MPa). A process for preparing a 3-alkenoic acid ester by adding an alkyl formate to a diene under pressure, comprising: a) a Pd-compound and b) one or more MCn _n- type compounds, wherein M is It has one meaning: an alkaline earth metal ion when n = 2; a group 4 metal ion when n = 4 (IV subgroup); a group 6 metal ion when n = 3, 5 or 6 (VI Sub-tribe )], Wherein the catalyst is used in the absence of an organic base containing phosphorus or nitrogen. 2. The method according to claim 1, wherein the catalyst further comprises CuCl ₂ and / or FeCl ₃ . 3. The method according to claim 1, wherein R _{1 to} R ₆ are each hydrogen. 4. The method according to claim 1, wherein R ₁ is methyl and R _{2 to} R ₆ are each hydrogen. 5. The method according to claim 1, wherein R ₇ is methyl, ethyl, propyl or butyl. 6. a) Pd-compound and b) 1 or more MCl _n-type compound [case, M has one of the meanings of the following: -n = 2 when the alkaline earth metal ions -n = 4, a metal ion of group 4 (IV subgroup) -n = 3, 5 or 6, a metal ion of group 6 (VI subgroup)]. A catalyst for performing the described method. 7. The catalyst according to claim 6, wherein M is Hf ⁴⁺ or Mo ⁵⁺ . 8. A catalyst MgCl ₂ and other MCl _n-type compound [case, M is ^Ti 4+, a ^{Zr 4+} or ^{Hf 4+]} containing catalyst according to claim 6. 9. The catalyst according to claim 6, which additionally contains CuCl ₂ . 10. The catalyst according to claim 9, wherein M is Mg ²⁺ , Ti ⁴⁺ , Zr ⁴⁺ or Hf ⁴⁺ . 11. The catalyst according to claim 6, which additionally contains FeCl ₃ .