FR2525590A1 - LIQUID-PHASE PREPARATION OF DELTA-CETOCARBOXYLIC ACID ESTERS USING A LIQUID-PHASE INSOLUBLE CATALYST - Google Patents

Abstract

A process for the preparation of delta-ketocarboxylic acid esters by addition reaction of a ketone and of an acrylic acid ester in the presence of a catalyst is described, which catalyst is formed by a mixture of a primary amine component and a catalytic material component which is accelerated by water. The catalytic material component which is accelerated by water, which is essentially or completely insoluble in the reaction medium, is selected from a group of materials which consists of an alkali half-salt of phthalic acid, an aluminium hydrosilicate material, a silica-alumina molecular sieve zeolite, a silica-free alumina and a sulphonated perfluorinated resin. The process is particularly suitable for the preparation of methyl 4-oxocaproate by the addition reaction of acetone to methyl acrylate.

Description

 The preparation of licoric ketocarboxy acid esters by the Kichael reaction of a ketone with an acrylic acid ester is well known. Improved catalysts for the reaction are of particular interest in the present case.

A reaction of the alkali-catalyzed ichelium ketone with an acrylic acid ester to give a delta-ketocarboxylic acid ester is described in Accounts
Rendus, 248, 1533-1535 (1959. An alkaline catalyst is used, as supplied by sodium amide or potassium ethylate, which catalyst is soluble in the reaction medium and reactive with the keto ester produced in the 'From layon reports low yields for most ketone starting materials,
Sinilary addition reactions have been reported, using catalysts which are soluble in reaction media. For example, in G3 patent 1,389,510 to
Stamicarbon BV, there is described a catalytic reaction of
Michael of a ketone with an acrylic acid ester giving a delta-ketocarboxylic acid ester. The reaction is catalyzed by a mixture of a primary amine and one of the different types of acidic compounds, all of which are soluble in the reaction medium. In GB patent 1,473,184 to Hoechst, a Michael addition reaction is described if miliary for the preparation of esters of 5-oxo-carboxylic acids (i.e. delta-keto esters) by reaction of a ketone with an ester of acrylic acid in the presence of a mixture of a primary groin and a party of different acids, all of which are soluble in the reaction medium. Each of these reactions catalyzed by an acid is disadvantageous in this sense due to the acid compound of the catalyst, soluble in the reaction medium, is difficult to separate from the reaction product, the delta0 keto ester. For the purification of the reaction product, for example by distillation, the combination of heat and the acidic catalyst typically causes the formation of undesirable by-products and therefore results in lower yields of delta-ketoester.

dans laquelle R peut être un groupe benzyle ou un grouse al- coyle de un à environ six atomes de carbone, R' peut être choisi parmi l'hydrogène, des groupes méthyle,. éthyle pro pyle et isopropyle et R" peut être un groupe alcoyle de un a environ 24 atomes de carbone..Une première étape du procédé consiste à former un milieu réactionnel pour la réaction d'une cétone possédant un hydrogène actif en position alpha avec un ester d'acide acrylique de formule générale

dans laquelle chaque R, R' et R" est tel que défini plus haut, le milieu réactionnel contenant de l"eau et une quantité efficace d'un catalyseur.Le catalyseur est fourni par un mélange d'un constituant à base d'amine primaire et d'un constituant à base d'une matière catalytique activable par de l'eau choisi dans le groupe consistant en un hémi-sel alcalin d'acide phtalique, d'un minéral à base d'hydrosilicate d'aluminium, un tamis moléculaire à base de silice et alumine, une alumine exempte ae silice et en une résine perfluorée sulfonée Ces matières catalytiques se caractérisent par le fait au'elles sont entièrement ou presque entièrement insolubles dans le milieu réactionnel. There is therefore a need for a process for the preparation of esters of delta-ketocarboxylic acids which makes it possible to obtain high yields of product by,
It is recommended according to the invention a process for obtaining in a single pass a high yield in an ester of delta-ketocarboxylic acid in the liquid phase, the delta-ketoester corresponding to the general formula

in which R can be a benzyl group or a crane alkyl of one to about six carbon atoms, R 'can be chosen from hydrogen, methyl groups ,. ethyl pro pyl and isopropyl and R "can be an alkyl group of one to about 24 carbon atoms. A first step of the process consists in forming a reaction medium for the reaction of a ketone having an active hydrogen in alpha position with a acrylic acid ester of general formula

wherein each R, R 'and R "is as defined above, the reaction medium containing water and an effective amount of a catalyst. The catalyst is provided by a mixture of an amine component primer and a constituent based on a water-activatable catalytic material chosen from the group consisting of an alkaline hemi-salt of phthalic acid, of a mineral based on aluminum hydrosilicate, a sieve Molecular based on silica and alumina, an alumina free of silica and of a sulfonated perfluorinated resin These catalytic materials are characterized by the fact that they are entirely or almost entirely insoluble in the reaction medium.

The reaction product mixture contains the ester
of delta-ketocarboxylic acid in contact with the catalytic material which is insoluble in the liquid phase of the reactive angel. Removal of insoluble catalytic material and subsequent distillation of the mixture of pro
reaction tubes provide a delta-keto acid ester
high purity carboxylic acid in the distillate, not contaminated by secondary by-products formed during the
distillation due to the presence of catalyst
duel from the addition reaction.

The process is particularly suitable for prerara-
tion; oo-4caproate ae methyl by the addition reaction,
methyl acrylate and acetone in the presence of an element
any of the family of specified catalytic materials.

An advantage of the process according to the invention is that, since the catalyst is largely or entirely
insoluble in the reaction medium, a reaction product free of catalyst can be obtained. During the
distillation of the reaction product to obtain a
delta-keto ester pure, relatively less harmful side products are formed, compared to the processes of the prior art in which the distillation takes place in the presence of acid catalyst.

A second advantage is that preferred compounds chosen from the family of catalytic materials are suitable for use in a fixed bed reactor insofar as
the selected catalyst is insoluble in the reaction medium
tional. From there, the addition reaction can be carried out continuously.

As the constitution of a reaction medium for the preparation of a delta-ketocarboxylic acid ester,
the reactive ketone and the acrylic acid ester,
starting materials of the generally defined type are introduced into a pressurized reactor with
stainless steel tation. The ketone serves as a 8. reaction time
tif and reaction medium. The ketone is usually present in a molar excess over the acrylic ester of twisting from about 7: 1 to about 15: 1.

 The appropriate ketones have an active or labile hydrogen on a carbon in alpha compared to the carbonyl of 12 ketone. Among these ketones are acetone, methylethyl ketone, methylproptl ketone, diethyl ketone, methyl isopropyl ketone ,. cyclonentanone, cyclohexanone, 2-methylcyclohexanone and -4-methylcyclohexanone.

Suitable acrylic acid esters corresponding to general formula II are esters of alpha & carboxylic acids, ss -unsaturated such as methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate , methyl crotonate, ethyl crotonate, methyl maleate, ethyl maleate, methyl fumarate and ethyl fumarate.

The addition reaction proceeds in the presence of a combination of cocatalyst provided by an amine and a water activated catalytic material. As suitable amines, mention may be made of methylamine, ethylamine, npropylamine, isopropylamine, n-butylamine, isobutylamine, dry butylamine, dry pentylamine, hexylamine, cyclopentylamine, cyclohexylamine and hexa methylstiamine. Generally, the amount of amine present in the reaction mixture is in the range of about 0.05 to about C, 5 moles per mole of starting material based on acrylic acid ester initially present in the reaction mixture
Examples of alkali metal phthalic acid hemi-salts suitable as catalytic materials are lithium hydrogen chloride, sodium hydrogen phthalate and potassium hydrogen phthalate. A preferred alkaline hemi-salt of phthalic acid is potassium hydrogen phthalate. These h6-mi-salts are largely but not entirely insoluble in water. It is thus oueJ when one of these salts is used as catalytic material, the quantity of water present in the reaction mixture will be the quantity necessary to activate the hemi-salt as a catalytic material but insufficient to dissolve an important part
aunt of the hemi-salt. The term "substantial portion" denotes the amount of hemi-salt which, when present during the distillation of the mixture of reaction products, does not promote the formation of sub- troublesome products.

Generally speaking, the quantity of water suitable for activating hemi-sel but which is insufficient to dissolve a significant part of the hemi-salt is between about ane to about five parts of water per part of hemisel in the total reaction mixture. Typically, an alkaline phthalic acid salt can be used as the catalyst material in an amount ranging from about 0.02 to about 0.13 part hemi-salt per part of ester ester. acrylic acid initially taken from the reaction mixture.

 A second suitable catalytic material is provided by a mineral based on aluminum hydrosilicate.

This material is characterized by the theoretical formula
Al2O3.4SiO2.H2O + H20 (III) and is generally known as Kontmorillonite.

Appropriate Montmorillonite-based catalytic materials are sold under the designation "K-Catalysts" tar
Süd-Chemie AG, unich, West Germany. These clay tyne materials are characterized in that they belong to the group of minerals with three layers, that they have a large number of exchangeable ions and that they are practically insoluble in water. In general, the aluminum hydrosilicate material can be present in an amount ranging from about 0.1 to about 4 parts by pieces of aluminum hydrosilicate for a tar of acid ester. Starting acrylic initially in the reaction mixture.

A third type of catalytic material is provided by a zeolite for molecular sieve based on silica and alumina in which the atomic ratio of silicon to 1 aluminum is about 10 to 1. The useful materials are typically characterized in that they have a specific surface of approximately 450 to approximately 500 m2 / g @ a water content of the order of approximately 1 to 15% by weight. The material is practically insoluble in water. Your particularly appropriated materials are sold commercially under the designation of "hydrogenated mordenite", Strem Chemicals, lnc., @Ewburyport, @ass. Generally, the silica and alumina zeolite may be present in an amount ranging between about 0.1 and about 4 parts by weight of silica and alumina zeolite per part of the starting acrylic acid ester initially present in the reaction mixture
A fourth type of catalytic material is provided by an alumina free from silica which is characterized in that it is practically insoluble in water. A suitable catalytic material based on silica-free A12C3 is sold under the designation HA 100 S by Houdry Process and Chemical Co., Div. from Air Products and Chemical Co.,
Inc., Phialadelphia, Pa. Generally, the silica-free alumina catalyst material may be present in an amount of the order of about 0.1 to about 4 parts by weight of alumina per part starting acrylic acid ester initially present in the reaction mixture.

 A fifth type of catalytic material is provided by a sulfonated perfluorinated resin prepared from copolymers of tetrafluoroethylene and of monomers such as fluoride o-e-erfluoro-dioxa-3-6-methyl-4-octane-7. The resin is practically insoluble in water.

Suitable resins are sold under the brand name NAFIONR 501 by DuPont Company, Wilmington, Del. Generally, the sulfonated perfluorinated resin may be present in an amount ranging from about 0.001 to about 0.04 part of resin for a portion of the starting acrylic acid ester initially present in the reaction mixture.

 For an addition reaction in which any of the fifth to fifth catalytic materials is used, there must be present in the reaction mixture an amount of water sufficient to induce the activity of the catalytic material. Since none of these specified catalytic materials is soluble to any detectable degree in any amount of water, the amount of water to be used can be determined simply by the amount of starting acrylic acid ester. , the quantities of excess water play no role in the formation of annoying by-products in the mixture of reaction products. Generally, the quantity of water used will, for any of the second, to fifth catalytic materials described, between approximately 0.02 and approximately 0.12 part in goids of catalytic material for a part of starting acrylic acid ester.

 To introduce the catalyst into a reaction mixture, the amine component and the component based on catalytic material can be added separately or as a mixture of the two components.

Before tistillation at a temperature high enough to recover a fraction of pure delta-ketocarboxylic acid ester, the insoluble or largely insoluble catalytic material must be removed from the liquid phase containing the delta acid ester. ketocarboxylic. In reactions using an alkaline hemi-salt of phthalic acid as a constituent of catalytic material it is necessary to carry out a dis
preliminary till about 10500 to remove any water from the reaction product mixture. Once the mixture of reaction products is freed from water, the alkaline hemi-salt of phthalic acid becomes practically insoluble in the reaction mixture and can be removed by filtration. For the second to fifth elements of the family of catalytic materials, the step of 'preliminary distillation' is not necessary since these materials are easily filterable from the mixture of reaction products due to their insolubility in the mixture independently of the amount of water present.

A filtrate obtained from either of these reaction mixtures can then be subjected to fractional distillation under reduced pressure with a view to recovering a fraction containing delta acid ester. high purity ketocarboxylic.

The following examples illustrate specific embodiments of the invention. The invention is however not considered to be limited to these embodiments, since there are of course many variations and possible modifications. Unless otherwise indicated, all percentages and parts in the examples as in the
description, are by weight.

Example I
1660 g of acetone, 215 g of methyl acrylate, 22 g of isopropylamine, 2 g were charged into a stainless steel pressure reactor with mechanical stirring and equipped with a temperature measurement and regulation means. hydroquinone, 10 g of potassium acid phthalate and 18 g of water. The free space of the reactor was swept with a stream of nitrogen so as to remove substantially all of the ambient oxygen in the reactor. The reaction mixture was then heated with stirring to a temperature of 13 to 1350C t maintained under these conditions for about 6 hours. A pressure of 21 x 10 5 Pa was observed after the reaction temperature had been reached. After cooling in the reactor to room temperature, the entire reaction mixture was transferred to a distillation apparatus. Then, acetone, unreacted methyl acrylate, isopropylamine and water were separated in the form of a distillate, the distillation temperature having been kept at a maximum of about 105 C. The residual product a-years the distillation apparatus was transferred to a filtration apparatus. Insofar as the potassium acid phthalate was largely insoluble in the product of the liquid reaction, there was almost complete separation of the potassium acid rhthalate from Liquid filtrate which contains crude methyl oxo-4-caproate (@OC) product. The crude @OC was passed through a bed of sodium bisulfate to remove residual basic material, such as isopropylamine, from the base product.
MOC. The product based on MOC was then introduced into a distillation apparatus and recovered in the form of a distillate at a distillation temperature of 120-124 ° C. under an absolute pressure of approximately 3333 PA. We have
isolated 328 g of purified MOC, which corresponds to a yield of al molar nar relative to the starting ethyl acrylate. Cn obtained a distillation residue of 14 g. Analysis by gas chromatography of the MOC product indicated a purity of the MOC greater than 99.5 '. A trace impurity has been identified as phorone.

Example II
An addition reaction was carried out with the equipment, the starting materials and according to the procedures generally described in Example I. To demonstrate the degree of conversion of the starting reagents to oxo-4-caproate methyl, samples of the reaction medium were taken during a five hour reaction period. Table I provides a list of methyl acrylate conversions and yields of methyl oxo-4-caproate for each of the samples.

Table I
Reaction of acetone and methyl acrylate to form
methyl oxo-4-caproate over a period of
five hour reaction
Conversion time of Yield in% Final yield reaction of acrylate by passage of- (in%) of oxo-4-
(hours) methyl (%) oxo-4-caproate methyl caproate (%) thyle (%)
2 79 70 9
3 88 79 89
4 94 86 91
5 97 90 93
Example III
An addition action was carried out with m.ent, the starting reagents and according to the procedures generally described in Example I. To demonstrate the water activating effect on the catalytic material activatable by water consisting in 4 g of po potassium hydrogen phthalate rar mole of starting methyl acrylate, two reactions were carried out side by side differing only in the presence or absence of water. In reaction (a), 7.2 g of water per mole of methyl acrylate was used. In reaction (b), no water was added.

The results are summarized in Table II.

Example IV
An addition reaction was carried out with the equipment, 1PS starting reagents and following the operating slurries generally described in Example I. To demonstrate the activating effect of water on the catalytic material activatable by the water consisting of 40 g of montmorillonite (K-306,
Sud Chemie AG) per mole of starting methyl acrylate, two reactions were carried out side by side differing only in the presence or absence of water. In reaction (a), 7.2 g of water was used per mole of methyl acrylate. In reaction (b), no water was added. The results are summarized in Table II.

Example V
An addition reaction was carried out with the equipment, the starting reagents and according to the procedures generally described in Example T. To demonstrate the activating effect of water on the catalytic material activatable by water consisting of 60 g of silica-free alumina (HA-1005, Houdry Proc. & hem. Co.) per mole of acryl
starting methyl late, two reactions were carried out side by side differing only in the amount of water present. In reaction (a), it was
used 7.2 g of water per mole of methyl acrylate.

In reaction (b), 2 g of water was used rar mole of methyl acrylate. The results are summarized in Table II.

Example VI
An addition reaction was carried out with the equipment, the starting reagents and according to the procedures generally described in Example I, except that 4C g of catalytic material based on zeolite for sieves molecular silica and aluminum ("Hydrogenated Mordenite", Strem Chem., Inc.) were used per mole of starting methyl acrylate. The results are summarized in Table II.

Example VII
An addition reaction was carried out with the equipment, the starting reagents and according to the procedures generally described in Example I, except that 0.4 g of sulfonated perfluorinated resin was used (NAFIONR 501, DuPont Co.) per mole of starting methyl acrylate. The results are summarized in Table II.

 Table II.

Preparation of methyl oxo-4-caproate (MOC) from acetone and methyl acrylate (MA) with selected catalytic materials activated by water and not activated by water.

Example No. Catalytic Material Time- Water yield
lytic reaction tivation in MOC
(hrs) (g / mole MA) (# molar)
III (a) 5 Hydrogenophta- 7, -2 90
(b) 5 potassium late 67
sium
IV (a) 5 montmorillonite 7.2
(b) 5 none 55
V (a) 4 alumina 7.2
(b) 5.5 2.0 74
VI 6 silica-alumina 7.2 74
VIT 6 perfluorinated resin 7.2 74
sulfonated
Example VIII
To show that the process of the invention is useful for brief reactions as they occur in continuous operations, an addition reaction was carried out with the equipment, the starting reagents and generally according to the procedures. described in Example I, with the exception of the following: 880 g of acetone were used and the reaction mixture was heated from room temperature to 2350C in 1.5 hours . As soon as the temperature of the reaction mixture reached 2.350C, the reaction mixture was cooled to 180C over five minutes and reached room temperature after an additional four hours. After distillation of the reaction mixture, methyl oxo-4-caproate was obtained with a yield of 9--.

 Although specific examples of the present invention have been presented above, there is no question of limiting the invention only to them but of including all the variants and modifications coming within the scope of the appended claims.

Claims (23)

Claims  1. A procedure for the preparation of a delta-ketocarboxylic acid ester corresponding to the general formula

 in which R may be a benzyl group or an alkyl group of one to about six carbon atoms, B 'can be chosen tarTi hydrogen, methyl, ethyl, propyl and isopropyl groups and R "can be a alkyl group of one to about 24 carbon atoms, characterized in that it consists of:  to constitute a reaction medium for the reaction with a c  tone having an active hydrogen in alpha position with  an acrylic acid ester corresponding to the general iormule

 dan-s laqueile each R, R 'and R "is as defined more  top, said reaction medium containing a catalyst,  the catalyst being produced by a mixture of a constituent  based on primary amine and a constituent based on my  catalytic third 'activated by water which is largely  tie insoluble in the reaction medium and the  Dase constituent of catalytic material activatable by  the water being c! lolsi in the group consisting of a hemi-  alkaline salt of putalic acid, a mineral with hydroelectric passage  aluminum silicate, a zeolite for molecular sieve  base @e silica and alumina, an alumina free of silica and  a sulfonated perfumed resin, whereby a mixture of reaction products containing a delta-ketocarboxylic acid ester can be formed in contact with a constituent based on the chosen catalytic material, which is substantially insoluble, which constituent can be almost entirely removed from the mixture of the products resulting from the reaction before distillation to obtain a delta-ketocarboxylic acid ester of high purity.  2. Method according to claim 1, characterized in that said constituent based on activatable catalytic material nar of water is an alkaline hemi-salt of phthalic acid, and  e rocédé conrrerlant further one of @ xième étare  of forming a distillation residue substantially  water-free Far distillation of the result of the first  reaction step, said distillation residue con  tracking in a liquid fraction in contact with a ma  solid content containing the alkaline hemi-salt of phta acid  lique, the liquid fraction containing the acid ester del  ta-ketocarbboxylic; whereby the liquid fraction can be separated from the solid material, the liquid fraction can then be treated for the recovery of remaining delta-ketocarboxylic acid relatively free of by-products and the solid material can then be treated for recovery of the alkaline hemi-salt of phthalic acid for reuse as a catalytic material.  3. Method according to claim 2, characterized in that said alkaline hemi-salt of phthalic acid is sodium hydrogen genophthalate.  4. Method according to claim 2, characterized in that said alkaline hemi-salt of phthalic acioe is potassium hydrogen phthalate.  5. Method according to claim 2, characterized in that said acrylic acid ester is methyl acrylate, that said ketone is acetone, that said delta-ketocarboxylic acid ester is oxo-4 - methyl caproate and that said alkaline hemi-salt of phthalic acid is either potassium hydrogen phthalate or sodium hydrogen phthalate or a mixture of the two.  6. Method according to claim 1, characterized in that constitute t; base of water activatable catalytic material which is insoluble in the reaction medium is selected from the group consisting of a mineral based on aluminum hyarosilicate, a zeolite for molecular sieve based on silica and alumina, an alumina free of silica and a sulfonated perfluorinated resin, the method further comprising a second step  removal by filtration of the constituent based on the  insoluble catalytic material chosen from the mixture of  reaction products, so this mixture of pro  reaction tubes can be distilled in the absence  - almost total constituent based on cataly material  tick to obtain a delta-ketocarboxylic acid ester  that of high purity.  7. Method according to claim 6, characterized in that said constituent based on water-activatable catalytic material is an aluminum hydrosilicate.  8. Method according to claim 6, characterized in that said constituent based on catalytic material activatable by 'water is a zeolite for molecular sieve' based on silica and alumina.  9. Method according to claim 6, characterized in that said constituent based on catalytic material activa  ble by water is a silica-free alumina.  10. Method according to claim-6, characterized in that said constituent based on catalytic material activatable tar water is a sulfonated perfluorinated resin.  11. Process for the preparation of methyl oxo-4-caproate, characterized in that it consists  a) reacting methyl acrylate with acetone in a reaction medium containing water and a catalyst to form a mixture of reaction products containing methyl oxo-4-caproate, said catalyst being constituted by a mixture of a primary amine and potassium hydrogen-phthalate, the water being present in an amount at least sufficient to act as an activator of said catalyst but in an insufficient amount  health to dissolve a large fraction of potassium hydrogen phthalate  b) distilling the reaction product mixture in step 2) to form a distillation residue containing methyl oxo-4-caproate and potassium hydrogen phthalate, said distillation residue being substantially free of 'water  c) treating the distillation residue to remove potassium hydrogen phthalate from the residue and thus provide a residue of distillation residue containing methyl oxo-4-caproate; whereby the remainder of the distillation residue can be treated by distillation to provide unified methyl oxo-4-caproate substantially free of side products.  12. The method of claim 11, characterized in that said potassium hydrogen phthalate is initially present in the reaction medium in an amount of about 0.07 to about 0.13 part of potassium hydrogen phthalate for a part of acrylate methyl.  13. The method of claim 12, characterized in that said water is initially present in the reaction medium in an amount of about one to about five parts of water per part of potassium hydrogen phthalate.  14. Process for the preparation of methyl oxo-4-caproate, characterized in that it consists  a) to make methyl acrylate regaire with acetone in a reaction medium containing water and a catalyst to give a mixture of the reaction products containing methyl oxo-4-caproate, said catalyst consisting of a mixture of a frimine amine and a mineral based on aluminum hydrosilicate, the water being present in a quantity at least sufficient to act as activator of said catalyst; ;  b) filtering the reaction product mixture from step a) to remove said mineral based on aluminum hydrosilicate which is insoluble in the mixture of reaction products in order to obtain a filtrate which is free of said mineral aluminum hydrosilicate  c) distilling the filtrate from step b) in order to obtain methyl oxo-4-caproate of high purity.  15. The method of claim 14, characterized in that said mineral based on aluminum hydrosilicate is initially present in the reaction medium in an amount between about C, 1 and about 4 perties of mineral based hydrosilicate d aluminum for a part of starting methyl acrylate.  16. The method of claim 14, characterized in that step a) is accomplished by continuous passage of methyl acrylate and acetone through a fixed bed co'prenant said matter based on nvdrosilicate of aluminum.  17. Process for the preparation of methyl oxo-4-caproate, characterized in that it consists  a) reacting methyl acrylate with acetate in a reaction medium containing water and a catalyst to form a mixture of the reaction products containing methyl oxo-4-caproate, said catalyst being composed of a mixture of a primary amine and a zeolite for molecular sieves based on silica and alumina, the water being present in an amount at least sufficient to act as activator of said catalyst;  b) filtering the mixture of reaction products  step a) to remove said zeolite for molecular sieves  re silica and alumina base which is insoluble in the mixture of reaction products in order to obtain a filtrate which is free from said zeolite;  c) distilling the filtrate from step b) in order to obtain methyl oxo-4-caproate of high roughness.  THE. Process according to Claim 17, characterized in that the said zeolite for molecular sieve based on atalumine silica is initially present in the reaction medium in an amount between approximately, 1 and approximately 4 rarties of zeolite for a part of methyl acrylate of departure.  19. Method according to Revenai ^ ation 18, characterized in that step a) is carried out by continuous passage of ethyl acrylate and acetone through a fixed bed comprising said zeolite for molecular sieves based on silica and alumina.  2, Process for the preparation of methyl oxo-4-caproate, characterized in that it consists  a) reacting methyl acrylate with acetone in a reaction medium containing water and a catalyst to give a mixture of the reaction products containing methyl oxo-4-caproate, said catalyst being composed of a mixture of a primary amine and a silica-free alumina, the water being present in an amount at least sufficient to act as activator of said catalyst  b) filtering the mixture of reaction products from step a) to remove said alumina which is insoluble in the mixture of reaction products in order to obtain a filtrate which is free of said alumina  c) distilling the filtrate from step b) in order to obtain high-purity methyl oxo-4-caproate.  21. The method of claim 20, characterized in that said alumina is initially present in the reaction medium in an amount between about 0.1 and about 4 parts of alumina and one part of methyl acrylate as a material of departure.  22. The method of claim 20, characterized in that step a) is carried out by continuous passage of methyl acrylate and acetone through a fixed bed containing said alumina.  23. Process for the preparation of methyl oxo-4-caproate, characterized in that it consists  a) reacting methyl acrylate with acetone in a reaction medium containing water and a catalyst @ r to form a mixture of the reaction products containing methyl oxo-4-caproate, said catalyst being composed of a mixture of a primary amine and  of a sulfonated perfluorinated resin, water being present in  an amount at least sufficient to act as an activator  of said catalyst;  b) filtering the mixture of reaction products  of step a) to remove said sulfonated perfluorinated resin  which is insoluble in the mixture of reaction products in  to obtain a filtrate which is free of said resin per  sulfonated fluoride  c), distilling the filtrate from step b) to obtain high-purity methyl oxo-4-caproate.  24. Method 'according to claim 23, characterized  in that said sulfonated perfluorinated resin is initial  present in the reaction medium in an amount included  between about 0.001 and about 0.04 part of terfluorinated - sulphonated resin for a part of starting methyl acrylate.  25. The method of claim 24, characterized  in that the step is accomplished by continuous passage of acryl-  methyl and acetone late through a fixed bed comprising  said sulfonated perfluorinated resin