DD206989A1 - METHOD FOR THE SELECTIVE PREPARATION OF ALKYL ALKENYL ETHERS FROM 1,3-DIENES - Google Patents

Abstract

A process for the selective preparation of alkylalkenyl ethers having a monomeric alkenyl structure from 1,3-dienes by homogeneous transition metal catalysis. The invention provides a process in which, depending on the quantitative and qualitative catalyst composition of isoprene, alkoxyisopentenes can be prepared selectively under mild reaction conditions in one process stage. The essence of the invention is that with a "in situ" formed palladium-catalyst complex in solution of a palladium (II) compound, a phosphorus (III) compound and a reducing agent with the addition of a protic component and an organic Solvent 1,3-dienes are converted to acyclic Alkylalkenylethern with monomeric alkenyl structure. Possible fields of application are: - processes for the preparation of methoxyisopentenes, - processes for the functionalization of higher, in particular terpene analogous, hydrocarbon structures, - etherification of substrates which can not be converted due to thermal instability or basic substituents by classical organic syntheses.

Description

233415

Title of the invention

Process for the selective preparation of alkylallcenyl ethers from 1,3-bis

Field of application of the invention

The invention relates to a Veri'anren for the selective production of Aikylalkenylethern with monomeric alkenyl structure of 1,3-dienes by homogeneous transition metal catalysis. This makes it possible, 1,3- iene such as isoprene to funktionalisleren sbedingungen under mild reaction ^D.

Characteristic of the known technical solutions

It is known to prepare alkyl alkenyl ethers-in particular methoxyisoprenes-by reductive decomposition of a corresponding palladium (II) complex. For this purpose, alladium (II) chloride, isoprene and methanol Moiverhältnis 1: 1: 1 respectively, and a complex of the composition (CH .., 0PdCl) ₀ is shown. This compound must then be isolated and cleaved by reductive decomposition into a mixture of methoxyisopentenes, the palladium precipitating in metallic form.

For a technical application, this invention is unsuitable due to the high demand for palladium, because it succeeds because of the stoichiometric ratio of palladium to isoprene of 1: 1 in Kotnplesverbindung described above only, per mole of palladium (II) chloride less than one mole Methoxyisopentene than Isomerengemisch to win »In addition, the hotien cost of separation of the resulting

IS ά 4 I 0 S

Palladium and its reoxidation to palladium (II) chloride, (For the production of one tonne of methoxyisopentene about 2 t of palladium (II) -chloride would have to be reactivated in this way) (Sü-PS 6ölü4ü, Sü-PS 7yi72?)

It is also known to produce alky! Alkenyl ethers by the thalomerization of 1,3-dienes. In this case, preference is given to butadiene or isoprene under catalytic conditions to octadienyl ethers or to dimethyloctadienyl ethers. implemented. The catalyst systems used here are, for example, palladium compound plus strong base in a primary or secondary alcohol (DE-OS 2148156), palladium (II) compound plus tertiary phosphine and a base (DE-OS 215 370), palladium (o) - pbosphinkomplexe (US-PS 37 ^ 9352) or palladium halide plus alkoxide (US Patent 3 ^ 990 ^ 2) for use, being carried out in the temperature range of 0 to 100 C.

In all of these inventions, however, the carbon chain of the monomer is doubled in the etherification.

A process in which, by the choice of suitable molar ratios of palladium to cocatalyst to alcohol, and by the choice of suitable solvents, 1,3-diene and alcohol in a molar ratio of 1: 1 can be linked to alkylalkenyl ethers with monomeric alkenyl structure, is not known yet. With the catalyst combination RhCl "or IrCl ,, or IrCl ^, alcohol and 1.3-3, for example, 50 g of 2,7-di-methylocta-1,3,7-triene in 250 ml of abs. Alcohol dissolved and reacted with 2 g of RhCl ,,, aq in .h8 hours at 20 C, with a selectivity of 53 %, a mixture of 2,7-dimethyl-5-ethoxy-octa-1,6-diene and 2 , 7-dimethyl-7-ethoxy-octa-1,5-diene formed. The disadvantage of this method, in addition to the low selectivity is that the addition reaction does not take place without Doppelblndtmgsisomerierutagen (DE-OS 2407898). The implementation of isoprene on RhCl, catalyst to 2-alko; xy-2-methyl-but-3-ene is unreasonable, taking into account the high catalyst costs for industrial use, (KAWAZURA, H. et al, Bull. Cfaem Soc, Japan, KS (6) , 19-9 (1975)).

233415

Object of the invention

The aim of the invention is to produce from 1,3-dienone under mild reaction conditions in a technically and economically acceptable method alkylalkenyl ethers having a monomeric alkenyl structure.

Explanation of the essence of the invention

The object was to produce acyclic alkylalkenyl ethers having a monomeric alkenyl structure from 1,3-dienes, in particular isoprene, by homogeneous transition metal catalysis in protic medium in one process stage.

This object is achieved by reacting a palladium (III) compound, a phosphorus compound, the protic component, an organic solvent and the 1,3-diene with the addition of a reducing agent. By mixing the catalyst components, "the active palladium catalyst is formed" in situ. "Isolation of the active complex in a defined form is not necessary for this process.

The reaction is carried out at temperatures of 0 to 100 C, preferably at 25 to 60 ° C, and pressures of 100 to 500 kPa. The molar ratios are from palladium to phosphorus to reducing agent to protic component including solvent to 1,3-diene 1 to 1 to 10 to 0.2 to 10 to 50 to 4000 to 50 to 1000.

The advantage over conventional methods is that

the active palladium catalyst complex does not first have to be preformed and isolated in a defined form,

the reaction proceeds catalytically,

- The activity and selectivity of the catalyst systems can be influenced by their quantitative and qualitative composition within wide limits and

the process with these catalyst systems enables the substitution of costly rhodium and iridium catalysts compared to known solutions.

9 Q {IC 7 -iO.J -j * i, QAO,. i>

As the palladium (II) compound, chelates of palladium such as acetylacetonate, palladium salts of carboxylic acids such as naphthenate, or palladium halides in the form of ligand-palladium (II) complexes can be used.

As the compound of the trivalent phosphorus, trialkyl or triarylphosphines such as tri-n-butylphosphine or triphenylphosphine, trialkyl or triaryl phosphites such as triethyl phosphite, or phosphorous triamides such as phosphorous tris-dimethylamide can be used. As added reducing agents, alkali metal carboxylates or alkoxides can be used.

As inert solvents, alkanes, such as n-octane, or aromatics, such as benzene, can be used.

The protic component can erfindungagemäß from a primary aliphatic or araliphatic alcohol in admixture with an organic solvent, such as secondary or tertiary aliphatic or cycloaliphatic alcohols, and / or an inert solvent, in particular alkanes or aromatics consist.

Ausfüfarungsbeispiele Example 1:

0.25 mmol (^ -C ₃ H ₅ PdCl) ₂ are mixed with 2 mmol of tri-n-butylphosphine,

1.5 mmol Na-fcriummethylat, 275 mmol methanol, 2? 0 raMpl benzene and 100 mmol isoprene and reacted at 60 C for 6 hours to react.

At 10% isoprene conversion, mathoxyisopentenes form with a selectivity of $ 60.

Example 2:

0.25 mmol of (-C ₃ H ₅ PdCl) ₂ are mixed with 3 mmol of tri-n-butylpbosphine,

1.5 mmol of sodium methylate, 275 mmol of methanol, 310 mmol of isopropanol and 100 mmol of isoprene and reacted at 60 C for 6 hours.

In seigenic isoprene conversion, 55 % methoxyisopentenes form.

233415 1

Example 3'-

0.5 mmol (tri-hapto-CH PdCl) ₂ is treated with 6 mmol of tri-n-butylphosphine, 1.5 mmol of sodium methylate, 475 mmol of methanol, 210 mmol of isopropanol and 100 mmol of isoprene and reacted at 60 C for 6 hours ,

It will be an isoprene conversion of. 95% , the yield of methoxyisopentenes is k6% .

Example ki

0.25 mmol of (tri-hapto-C ₃ H ₅ PdCl) ₂ are mixed with 2 mmol of bis (diphenyl) phosphinoethane, 1.5 mmol of sodium methylate, 200 mmol of methanol, 2 5 mmol of isopropanol, 56 mmol of benzene and 100 mmol of isoprene was added and reacted for days at room temperature.

The yield of Methoxyisopentenen is 25 % _t whereby an isoprene conversion of 70 % is achieved.

Example 5:

0.25 mmol (tri-bapto-C ₃ H ₁₅ PdCl) ₂ are admixed with 2 mmol of tri-n-butylphosphine, 1.5 mmol of sodium methylate, 200 mmol of methanol, 1 7 -7-octene-n-octane and 100 mmol of isoprene and h - Days reacted at room temperature.

The yield of Methoxyisopentenen is 75 %, with an isoprene conversion of 70 % is achieved.

Example 6:

0.25 mmol (tri-hapto-C ₃ H ₅ PdCl) ₂ are admixed with 3 mmol of tri-n-butylphosphinate, 1.5 mmol of sodium metbylate, 200 mmol of methanol, 312 mmol of isopropanol and 100 mmol of isoprene and reacted at room temperature for k days brought. At $ 90 isoprene turnover, 5 % methosysopentenes are formed,

'/ H Π l · 7

Q - ·

TSS h 1

Example 7:

0.25 mmol (tri-bapto-CH ₁₅ PdCl) ₂ are admixed with k mmol of tri-n-butylphosphine, 1.5 mmol of sodium methylate, 200 mmol of methanol, 312 mmol of isopropanol and 100 mmol of isoprene and reacted for hours at room temperature.

At 63 % isoprene conversion, 65 % methoxyisopentenes are formed.

Example 8:

0.5 mmol Palladiiimacetylacetonat are mixed with 3 mmol of tri-n-butylphosphine, 1.5 mmol of sodium methylate, 200 mmol of methanol, 312 mmol of isopropanol and 100 mmol of isoprene and reacted for hours at room temperature. $ 78 igetn Isoprenumsatz 52 fo Methoxyisopentene be formed.

Example 9

0.25 mmol (tri-hapto-CH ₅ PdCl) ₃ are mixed with 2 mmol of tri-n-

butylphosphine, 1.5 mmol of sodium methylate, 400 mmol of methanol, 210 mmol of isopropanol, 35 mmol of n-heptane and 100 mmol of isoprene.

After a reaction time of 5 hours at an isoprenutnose of $ 75, the methoxyisopentene amount formed is $ 55.

Example 10:

0.5 mmol of bis (benzonitrile) palladium (II) chloride are mixed with 3 mmol of tri-n-butylphosphine, 1.5 mmol of sodium methylate, 200 mmol of methanol, 312 mmol of isopropanol and 100 mmol of isoprene and reacted for hours at room temperature , At 73% isoprene conversion, 53 % methoxyisopentenes are formed.

2334 15 1

Example 11:

0.25 mmol of di-my-chloro-bis (-metbo-Ty-a-methyl-tri-hapto-butenyl) -dipalladium (II) are mixed with 3 mmol of tri-n-butylphosphine, 1.5 mmol of sodium aminomethylate, 200 mmol Added methanol, 312 mmol of isopropanol and 100 mmol of isoprene and reacted for k days at room temperature

At 7% isoprene conversion k2 fa metboxyisopentenes are formed.

Example 12:

0.5 mmol of palladium (II) phenyl-imino-o-cresylate are admixed with 3 mmol of tri-n-butylpbosphine, 1.5 mmol of i-sodium methylate, 200 mmol of methanol, 312 mmol of isopropanol and 100 mmol of isoprene, and for k days at room temperature reacted. At 67 % isoprene use 53 % Methoxyisopentene be formed.

Example 13:

0.25 mmol (tri-hapto-CH ₅ PdCl) ₂ are mixed with 2 mmol of tri-n-butyl-phosphine, 1.5 mmol of sodium methylate, 200 mmol of methanol, 26 mmol of benzene and 100 mmol of isoprene and reacted for k days at room temperature.

With 92 % isoprenutnose 70 % Methoxyisopentene be formed.

Claims (5)

Claim for invention 1. A process for the selective preparation of alkylalkenyl ethers having a monomeric alkenyl structure from 1,3-dienes in the presence of homogeneous catalysts comprising a transition metal compound, a compound of trivalent phosphorus, a reducing agent and a protic component, characterized in that the palladium {II) - Compound, the phosphorus (ill) compound, the reducing agent, the protic component, an organic solvent and the 1,3-diene are mixed and thus the catalytically active complex is formed "in situ", the reaction at temperatures from 0 to 100 C, preferably at 25 to 60 C, pressures of 100 to 500 kPa, preferably under the vapor pressure of the reaction mixture, and a molar ratio of palladium to phosphorus to reducing agent to protic component including solvents of 1,3-diene of 1 to 1 to 10 0.2 to 10 to 50 to 2000 to 50 to 1000 is complied with. 2. Method according to point t, characterized in that as PaHadium (il) compounds chelates of palladium, carboxylic acid salts or halides in the form of ligand-palladium (II) complexes can be used. 3. The method according to item 1 and 2, characterized in that are used as phosphorus (ill) compounds Trialkyl- or triarylphosphines, trialkyl or Triarylphospbite or Pbosphorigsäuretriamide, 4. Process according to items 1 to 3, characterized in that the reducing agents used are alkali metal carboxylates or alkoxides. 5. The method according to item 1 to k, characterized in that as protic components a primary aliphatic or araliphatic alcohol in admixture with an organic solvent, such as secondary or tertiary aliphatic or cycloaliphatic alcohols, and / or an inert solvent, in particular alkanes or aromatics, be used. 2 a BEZ. 19 ,: i * ί-ν η η M ·; ·: -Ν