WO2012116977A1

WO2012116977A1 - PROCESS FOR THE PREPARATION OF 3-METHYLENE-γ-BUTYROLACTONE

Info

Publication number: WO2012116977A1
Application number: PCT/EP2012/053345
Authority: WO
Inventors: Stefaan Marie André DE WILDEMAN; Johannes Gerardus De Vries; Jeroen Antonius Franciscus Boogers
Original assignee: Dsm Ip Assets B.V.
Priority date: 2011-02-28
Filing date: 2012-02-28
Publication date: 2012-09-07

Abstract

The invention relates to a process for the preparation of 3-methylene-γ-butyrolactone (Z), the process comprising a hydroformylation step wherein 1,4-butene-diol (X) or its ester derivative cis-1,4-diacetoxy butene (Y) is subjected to H₂ gas and CO gas in the presence of a hydroformylation catalyst, thereby forming an intermediate product comprising a mixture of compounds containing an aldehyde group or a hemiacetal, and an oxidation step wherein the intermediate product or hydrolyzed derivative thereof is oxidized by an oxidation agent thereby forming Z.

Description

PROCESS FOR THE PREPARATION OF 3-METHYLENE-Y-BUTYROLACTONE

The invention relates to a process for the preparation of an alpha- methylene-lactone, more particular 3-methylene-Y-butyrolactone.

Alpha-methylene-lactones can be used for producing polymeric materials by copolymerization with suitable co-monomers such as methacrylates or styrene. Such an alpha-methylene-lactone and its preparation method are described in EP-0841332-A1. The alpha-methylene-lactone in ΕΡ-0841332-Α1 is alpha-methylene- beta-methyl-butyrolactone. As described in ΕΡ-0841332-Α1 various routes for the synthesis of alpha-methylene-beta-methylbutyrolactone were known, but these were all complex processes, only suited as pure laboratory method and involving relatively expensive chemicals. Likewise, many of the mentioned reaction steps are not feasible on an industrial scale or would require costly technical equipment. ΕΡ-0841332-Α1 describes a new process for the production of alpha-methylene-beta- methylbutyrolactone that is claimed to have improved yields and lower cost starting materials and suitable for use in conventional large-scale production units The process of ΕΡ-0841332-Α1 starts from alpha-methylene-3-methyl-4-hydroxybutyraldehyde (a) or its tautomeric form 2-hydroxy-3-methylene-4-methyltetrahydrofuran (b) by an oxidation step. This step is said to have high yield. The starting products (a) and (b) themselves are produced from isobutenol or isobutenylacetate, which involves a hydroformylation step to form a half-acetal or an aldehyde, and a Mannich reaction with formaldehyde to introduce the alpha-methylene group. Overall, this is still a complex multistep process and involves formaldehyde. Formaldehyde is toxic and difficult to handle as its trimeric form may precipitate anywhere on the used equipment, whereas its gaseous nature makes it spread very rapidly.

Alpha-methylene-lactones can also be accessed by forming a methylene moiety via C1 addition with formaldehyde on the alpha carbon atom of already formed substituted or unsubstituted lactones. However, this process poses serious problems. The use of formaldehyde is undesirable for the reasons outlined above. Furthermore, catalyst inactivation can be caused by deposition of condensation products on its surface preventing reaction between catalyst and reactants. Due to unwanted inactivation of the basic catalyst ideally used in gas phase facilitating formaldehyde addition onto already formed substituted or unsubstituted lactones, reaction rates of the alpha carbon atom linkage to formaldehyde tend to drop in time. These problems cause serious hurdles for up-scaling and industrial implementation of these processes. Although catalyst design and process engineering might partly solve this problem, alpha-methylene-lactones have not been produced on industrial scale so far.

The aim of the present invention is to provide a process for the preparation of an alpha-methylene-lactone that is based on economically favorable raw materials, gives good yields, and is preferably less complicated and/or formaldehyde free.

This aim has been achieved with the process according to the invention, in which the alpha-methylene-lactone produced is alpha-methylene-v- butyrolactone, also known as 3-methylene-Y-butyrolactone (herein also referred to as Z), the process comprising a hydroformylation step wherein 1 ,4-butene-diol (X) or its ester derivative cis-1 ,4-diacetoxy-butene (Y) is subjected to H₂ gas and CO gas in the presence of a hydroformylation catalyst, thereby forming an intermediate product comprising a mixture of compounds containing an aldehyde group or a hemiacetal, and an oxidation step wherein the intermediate product or hydrolyzed derivative thereof is oxidized by an oxidation agent thereby forming Z.

The effect of this process is that it produces the desired product Z in a limited number of steps, is formaldehyde free, and 1 ,4-butene-diol as well as the diacetate are inexpensive raw materials that originate from existing large-scale industrial processes,

Starting from 1 ,4-butene-diol (further herein referred to as X), only two steps are needed. The hydroformylation of the unsaturated diol results in formation of a mixture of intermediate products, such as the compounds 4-hydroxy-2- (hydroxymethyl)butanal (X1), 4-hydroxy-2-methyenebutanal (X2), 3-(hydroxymethyl)-2- hydroxy-tetrahydrofuran (X3) and 3-methylene-2-hydroxy-tetrahydrofuran (X4) (see reaction route 1). Both compounds with an aldehyde group and an open structure and compounds with ring closed hemiacetal structure may occur next to each other. For example in particular cases, compounds X2 and X3 were present together in a predominated amount next to traces of X1 and X4. Surprisingly, upon oxidation, without the need of purification or separation of one of these intermediates, the mixture is converted primarily into the desired Z(see reaction route in Scheme 2).

oxidation

3-methylene- gamma-butyrolactone

(Z)

Scheme 1 : Reaction route starting from 1 ,4-butenediol (X)

Starting from the ester derivative cis-1 ,4-diacetoxy-butene (further herein referred to as Y), hydroformylation yields mainly 2-formylbutane-1 ,4-diacetate (Y1) with traces of 3-formylbut-3-enyl-1 -acetate (Y2), 3-

(hydroxymethyl)tetrahydro-furan-2-yl-acetate (Y3) and 3-methylenetetrahydrofuran-2- yl-acetate (Y4) also formed. Treatment with acid leads to formation of 2-formyl-3- butene-3-yl-acetate (Y2). Y2 has to be hydrolyzed before, during or after the oxidation step. The hydrolysis can be performed by an acidification step wherein the intermediate product or oxidation product thereof is subjected to an aqueous acid. Formally 3 steps are needed, but the acidification step and the oxidation step can be performed as a one-pot synthesis and can optionally also be performed at the same time, directly yielding the ring closed alpha-methylene-lactone product (see reaction route in Scheme 2).

3-methylene- gamma-butyrolactone (Z)

Scheme 2: Reaction route starting from cis-1 ,4-diacetoxybutene (Y)

As mentioned in EP-0841332-A1 the hydroformylation of ethylenically unsaturated compounds with hydrogen and carbon monoxide as an industrially applicable synthetic step for the production of aldehydes is known and is also described for substituted allyl alcohols in Chemiker-Ztg. 101 , 343 (1977). In the process of EP-0841332-A1 the hydroformylation step results in a half-acetal or an aldehyde, and the methylene group is formed in the Mannich reaction with

formaldehyde. In the process according to the invention, the methylene group is formed directly in the hydroformylation step or in the ensuing acid treatment or in the oxidation step. The reaction with formaldehyde can be completely omitted, eliminating all related problems.

Hydroformylation is a standard technology that is used to produce a variety of bulk chemicals on a very large scale. The hydroformylation of X or Y can proceed via standard protocols reported in the literature which are known to the man skilled in the art. The catalyst can be any hydroformylation catalyst, for example a Cobalt, Iridium, Rhodium, Ruthenium, Osmium or Palladium based catalyst; Rhodium catalysts are preferred. Generally, these catalysts are complexes of transition metals coordinated or chelated by monodentate or multidentate ligands. In addition they may contain counter ions if their oxidation state is greater than 0. Suitable anions may be halides, acetate, acetylacetonate, BF₄ ^", or the like. Suitable ligands comprise hydride, carbon monoxide (CO), or phosphorus containing ligands such as monodentate or bidentate phosphine ligands, monodentate, bidentate, tridentate or tetradentate phosphite ligands, monodentate or bidentate phosphonite ligands, monodentate or bidentate phosphinite ligands or monodentate or bidentate phosphoramidite ligands, monodentate or bidentate phospholes, phospholines or phospholidines. If the ligand is bidentate the two phosphorus atoms may be different, for instance a combination of a phosphine with a phosphite. All combinations are possible. The two phosphorus atoms are linked through a bridge which may be an alkylidene or an arylene type bridge or a combination thereof. The bridge may also contain heteroatoms such as oxygen , nitrogen, sulfur or phosphorus. If the ligand is monodentate, anywhere between one and three ligands may be coordinated to the metal. These ligands can be the same or different.

Examples of suitable ligands are both triaryl phosphines and triaryl phosphites. Other suitable ligands are bis(diarylphosphino)alkanes such as Ar₂P-(CH₂) n-PAr₂ with n = 2- 6. The aryl can be substituted with any group as long as the substituent does not interfere with the hydroformylation. Particularly preferred examples for

triarylphosphines, are triphenylphosphine, triphenylphosphinetrissulfonate,

triphenylphosphinemonosulfonate, tris-(2-methylphenyl)phosphine, tris-(2,6- dimethylphenyl)phosphine, tris-(2-isopropylphenyl)phosphine, tris-(2- phenylphenyl)phosphine, tris-(2 - t-butylphenyl)phosphine, tris-(2,4-di-t- butylphenyl)phosphine and tris-(2-methyl-4-chlorophenyl)phosphine. Particularly preferred examples for triaryl phosphites are triphenyl phosphite, tris-(2- methylphenyl)phosphite, tris-( 2,6-dimethylphenyl)phosphite, tris-(2- isopropylphenyl)phosphite, tris-(2-phenylphenyl)phosphite, tris-(2-t- butylphenyl)phosphite, tris-(2,4-di-t-butylphenyl)phosphite and tris-( 2-methyl-4- chlorophenyl)phosphite. Phosphites containing ortho substituents are more stable towards hydrolysis and are preferred. Bidentate phosphites may also be used.

Examples of suitable bidentate phosphites that can be used are described in US 5,874,641 , US 5,631 ,392, US4,769,498, US4.885.401 , EP0213639 or EP-518241 , without being limited by these examples.

The catalysts may be used as pre-formed complexes, but often it is advantageous to use a catalyst precursor in combination with one or more ligands. Examples of catalyst precursors are ruthenium compounds Ru₃(CO)i₂, Ru(N0₃)₃, RuCI(PPh₃)₃ and Ru(acac)₃, the palladium compounds PdCI₂, Pd(OAc)₂, Pd(acac)₂, PdCI₂(COD), Pd (PPh₃)₄, PdCI₂(PPh₃)₂, PdCI₂(CH₃CN) ₂ and PdCI₂(PhCN) ₂, the osmium compounds Os₃(CO)i₂ and OsCI₃, the iridium compounds lr₄(CO)i₂ and lrS0₄, the platinum compounds K₂PtCI₄, PtCI₂(PhCN) ₂, Na₂PtCI₆.H20, PtCI₂ and PtCI₄, the cobalt compounds CoCI₂, Co(N0₃) ₂, Co(OAc) ₂, Co₂(CO)₈ HCo(CO)₄ and

Co(acac)₂.xH₂0 and rhodium RhCI₃, Rh(N0₃)₃, Rh(OAc)₃, Rh₂0₃, [Rh(acac)(CO)₂], [Rh(OAc)(COD)] ₂, Rh₄(CO)₁₂, Rh₆(CO)₁₆, HRh(CO)(PPh₃)₃, [ Rh(OAc)(CO) ₂] ₂ and [RhCI(COD)] 2 (acac is acetylacetonate, Ac is an acetyl group, COD is 1 ,5- cyclooctadiene and Ph is a phenyl group). It must be said that the group be used 8-10- metal compound are not limited to the examples listed above. [Rh(acac)(CO)₂] is a preferred catalyst precursor. It is noted that the usable ligands are not limited to the examples listed above.

Suitably, the reaction conditions are as follows. The metal concentration in the reaction mixture is suitably in the range 10-10000 ppm and preferably between 100 and 1000 ppm. The molar ratio of ligand to metal is in the range 0.5 to 100 and preferably in the range 1 to 20. The temperature of the reaction is in the range 0-200°C and preferably in the range 50-150 °C. The hydroformylation is suitably done under a gas atmosphere comprising hydrogen gas (H₂) and carbon monoxide (CO). The pressure is in the range of 1-200 bar and preferably in the range from 5-50 bar. The molar ratio of hydrogen to carbon monoxide is between 10: 1 and 1 : 10 and preferably in the range 1 : 1 to 6: 1. Most preferred is a ratio of 1 : 1.

The reaction can be carried out either without solvent or with solvents. The reaction can be used both in common solvents as well as directly in the bulk substance, the highest rates are obtained directly in bulk. Suitable solvents are: saturated and aromatic hydrocarbons, such as benzene, toluene or cyclohexane, methylcyclohexane and hexane; ethers, such as tetrahydrofuran, dioxane, dimethoxyethane, dietyleneglycol dimethylether (diglym) and trietyleneglycol dimethylether (triglym); and ketones, such as cyclohexanone, methyl isobutyl ketone and acetone. Furthermore, esters are used, such as ethyl acetate or propyl acetate.

The hydroformylation may also be carried out in a 2 phase system combining an organic solvent and water. Suitably the starting compound X or Y is present in the organic solvent, whereas the catalyst is present in water. Other possible two-phase systems comprise the combination of an organic solvent with a fluorinated solvent or with an ionic liquid. In those cases the catalyst is preferentially soluble in a fluorinated solvent or an ionic liquid respectively.

Preferably, the hydroformylation of 1 ,4-butenediol is performed in the presence of a base to prevent the formation of acetals. Suitably, the base is a mineral base, such as potassium carbonate, or a tertiary amine, for example,

tris(hydroxyethyl)amine.

For the acidification step applied to the hydroformylation product of Y, resulting in hydrolysis of that product likewise followed at least partially by ring-closure resulting in formation of the mixture of intermediates as described before, any aqueous acid can be used. Examples are acetic acid, dilute sulfuric acid or dilute hydrochloric acid.

Oxidation catalysis is another general and well established method used in a very diverse range of products cumulating to more than 10 millions of tons annually. For the oxidation step to produce 3-methylene-Y-butyrolactone (Z), it has surprisingly been found that it is possible to oxidize the mixture of intermediates resulting from the hydroformylation of X, or the mixture intermediates resulting from the hydroformylation of Y in the presence of an acidic aqueous catalyst, to give

preferentially the desired product Z. However, it is also possible to oxidize the single intermediate products. Thus any of X1 , X2, X3,or X4 may be oxidized and any of Y1 , Y2, Y3 or Y4 may be oxidized in the presence of and aqueous acid, or otherwise hydrolyzed with an aqueous acid before or after the oxidation step. The oxidation step may be performed in a number of ways. One straightforward method is the use of a peracid as oxidant; peracetic acid is a preferred peracid. This has the added advantage that peracetic acid is acidic enough to catalyze the hydrolysis of compounds Y to compounds X, allowing the direct formation of compound Z from compounds Y without a separate hydrolysis step. A preferred method is oxidation with palladium metal and oxygen (Pd/02 catalyst). The palladium catalyst may be a salt, such as palladium acetate or palladium trifluoroacetate, it may be in the form of palladium nanoparticles or it may be in the form of a Pd(ll)complex. The latter complex conveniently has di- nitrogen ligands, such as bipyridine or 1 ,10-phenanthroline, or bisimines. Other metals may also be used for this oxidation, such as oxidation catalysts based on copper, iron, manganese or tungsten. These may also be in the form of a salt, nanoparticles or a complex. In addition to oxygen, it is also convenient to use hydrogen peroxide as oxidant. It is also possible to perform the oxidation of intermediate compounds X1-4, either individually or any mixture thereof, or Y1-4, either individually or any mixture thereof, with a ketone as oxidant (Oppenauer oxidation). Suitable ketones are acetone, butanone and cyclohexanone. Many Oppenauer catalysts have been described in the literature and are known to someone skilled in the art. Suitable examples include compounds based on aluminum, such as aluminum isopropoxide, ruthenium

complexes of the general form RuX₂L_n wherein X is a counter ion such as a halide, acetate or acac, or X is a hydride and L is a ligand, such as phosphorus ligands as described above for the hydroformylation reaction or cyclometallated ligands, or nitrogen ligands such as bipyridine or 1 , 10-phenanthroline or palladium catalysts as described above.

Optionally the acidification step and oxidation step are combined. This can be done, for example, by use of a per-acid, e.g. per-acetic acid.

The oxidation step can be performed in a solvent free system, or in a solvent containing system. In the latter case, the solvent preferably is an oxidation resistant solvent, for example acetic acid or ter-butanol or a halogenated solvent. The oxidation with per-acid is suitably performed at a temperature in the range of 0-100 °C, and preferably around 50°C. The oxidation with Pd or other metal catalysts is suitably performed at a temperature in the range of 50-100 °C, and preferably around 70°C.

The intermediate product formed in the hydroformylation step, as well as the product Z formed upon the optional acidification step and the oxidation step can be separated from the respective catalysts and isolated from the respective reaction media by standard operations for separating liquids from solvents, e.g. by filtration or evaporation, and for separating different liquids, such as distillation.

In summary, one can say that the process according to the invention presented is without the use of expensive chemicals and without the use of complicated technical process equipment, which can be converted simply to an industrial scale.

The invention is further illustrated by the following examples. Example 1 : hydroformylation of 1 ,4-butene-diol (X).

A 150 ml Hasteloy C autoclave was charged in a nitrogen

atmosphere with 4.1 mg (0.016 mmol) Rh(CO)2acetylacetonate, 4.8 mg (0.01 1 mmol) diphenylphosphinobutane, 0.9748 g (1.506 mmol) tris(2,4-t-butylphenyl)phosphate, 100 μΙ triethanolamine, 12.5 ml toluene, 50 ml trietyleneglycol dimethylether and 15 ml (182 mmol) 1 ,4-butene diol. Syngas (CO/H2 = 1/1) was charged to the autoclave and the reaction mixture was hydroformylated at 50 °C and 100 bar for 2h and 30 min, leading to a mixture of mainly 4-hydroxy-2-methylenebutanal and

3-(hydroxymethyl)tetrahydrofuran-2-ol with traces of 4-hydroxy-2- (hydroxymethyl)butanal and 3-methylenetetrahydrofuran-2-ol.

Example 2: synthesis of 3-methylene γ-butyrolactone by oxidation of mixture of hydroformylated 1 ,4-butenediol compounds with peracetic acid.

10 ml of the reaction mixture from example 3 was charged in a nitrogen atmosphere to a glass tube, to which 55.4 mg (0.29 mmol)p-toluene sulfonic acid and 155 mg 2,6-di-t-butyl-4-methyl phenol were added. This mixture was heated for 30 min at 80°C. Then 0.5 ml of the reaction mixture was oxidized with 0.25 ml peracetic acid (made from 4/6 v/v acetic acid/35% H202 and 1 drop concentrated sulfuric acid, and heating at 50 °C for 15 h). GC-MS confirmed partial conversion of the mixture into 3-methylene γ-butyrolactone.

Example 3: hydroformylation of cis-1 ,4-diacetoxy butane (Y)

A 150 ml Hasteloy C autoclave, fitted with a top stirrer was charged in a nitrogen atmosphere with 0.5 g (0.54 mmol, 1 eq.) RhH(CO)(PPh3)3, 50 ml toluene and 50 ml (314 mmol, 581 eq.) cis-1 ,4-diacetoxy butane. Syngas (CO/H2 = 1/1) was charged to the autoclave at 60 bar and the reaction mixture was heated to 80°C for 26,5 h, at constant overpressure of 60 bar. Occurrence of hydroformylation product 2- formylbutane-1 ,4-diyl diacetate was confirmed by GC analysis. Distillation of the product in the presence of traces of acid yielded pure 3-formylbut-3-enyl acetate. Example 4: synthesis of 3-methylene γ-butyrolactone by oxidation of 3-formylbut-3- enyl acetate with peracetic acid.

An NMR tube was filed with 0.5273 g of 3-formylbut-3-enyl acetate, 0.0073 g 2,6-di-t-butyl-4-methyl phenol and 0.5423 g peracetic acid (made from 4/6 v/v acetic acid/35% H202 and 1 drop concentrated sulfuric acid). This mixture was heated at 50 °C for 15 h. Conversion to 3-methylene γ-butyrolactone was confirmed by 1 H- NMR and GC-MS.

Claims

1. Process for the preparation of 3-methylene-Y-butyrolactone (Z), the process comprising a hydroformylation step wherein 1 ,4-butene-diol (X) or its ester derivative cis-1 ,4-diacetoxy butene (Y) is subjected to H₂ gas and CO gas in the presence of a hydroformylation catalyst, thereby forming an intermediate product comprising a mixture of compounds containing an aldehyde group or a hemiacetal, and an oxidation step wherein the intermediate product or hydrolyzed derivative thereof is oxidized by an oxidation agent thereby forming Z.

2. Process according to claim 1 , wherein the hydroformylation catalyst is a Co, Rh or a Pd catalyst, preferably a Rh catalyst.

3. Process according to claim 1 or 2, wherein the hydroformylation is carried out in an organic solvent, preferably in trietyleneglycol dimethylether or toluene.

4. Process according to any of claims 1-3, wherein the hydroformylation step of X is carried out in the presence of a base.

5. Process according to claim any of claims 1-3, wherein intermediate product formed upon hydroformylation of Y is subjected to treatment with an acidic aqueous solution prior to or simultaneously with the oxidation step.

6. Process according to claim 5, wherein the intermediate product is reacted with a per-acid so that the acidification and oxidation are combined.

7. Process according to any of claims 1-6, wherein the oxidation step is carried out in a solvent, preferably acetic acid or tert-butanol.

8. Process according to any of claims 1-7, wherein the intermediate product is separated from the hydroformylation catalyst and Z is isolated by distillation.