WO2011067386A2 - Method for producing aliphatic aldehydes - Google Patents

Abstract

The invention relates to a method for producing aliphatic aldehydes of the general formula (I) by reacting aldehyde of the general formula (II) with an aldehyde of the general formula (III), where R¹ is hydrogen or a methyl group, R² is a straight-chain or branched alkyl radical having 1 to 4 carbon atoms, and the two X are each hydrogen or together are a further C-C bond, in the presence of an aldol condensation catalyst to form the substituted octenal of the general formula (I) and subsequently optionally hydration, either continuously or in batches, to form the corresponding octanal of the formula (I). The invention is characterized in that the aldehydes of the general formula III and II are used in a molar ratio of III:II between 1.4:1 and 0.6:1.

Description

 Process for the preparation of aliphatic aldehydes

The present application claims the priority of EP 09 178 052.8. The priority document is incorporated by reference in its entirety into the present disclosure (= incorporated by reference in its entirety).

All documents cited in the present application are incorporated by reference in their entirety into the present disclosure (= incorporated by reference in their entirety).

The invention relates to a process for the preparation of aliphatic aldehydes of the general formula I.

in the

R ^{1 is} hydrogen or a methyl group,

R ^{2 is} a straight-chain or branched alkyl radical having 1 to 4 C atoms, preferably a methyl or ethyl group, and the two X are each hydrogen or together represent another CC bond, and use of the aliphatic aldehydes thus prepared as fragrances ,

State of the art:

Because of the generally dependent on many unpredictable factors uncertain availability of many natural fragrance components as well as the necessary adaptation to changing fashionable tastes, the fragrance industry has a constant need for new fragrances, either alone or in the form of compositions valuable fragrances with interesting fragrance notes. In addition, there is a growing trend towards the perfuming of everyday products, such as cosmetics and cosmetics technical articles such as glues, detergents and cleaners, for room sprays and other determine.

From EP 0 252 378 A1 and W.R. Grumpy, H. Siegel, tetramethyloctanal and derivatives - a new fragrance class, Liebigs Ann. Chem. 1988, 487-489, a process for the preparation of aliphatic aldehydes of the general formula I is already known. However, a disadvantage of this method is, inter alia, that it does not run continuously and thus has limited applicability for large-scale application. Furthermore, it is a disadvantage that a large amount of unwanted by-products is formed.

Task:

 Object of the present invention is to provide a novel advantageous process for the preparation of aliphatic aldehydes of the general formula I.

in the

R ^{1 is} hydrogen or a methyl group,

R ^{2 is} a straight-chain or branched alkyl radical having 1 to 4 C atoms, preferably a methyl or ethyl group, and the two X are each hydrogen or together represent another CC bond to provide.

 The new process should be particularly simple, inexpensive and effective and suitable for large-scale application.

 The process is intended to enable the continuous preparation of the aliphatic aldehydes of the formula I.

 The process according to the invention should proceed in such a way that the autoaldol reaction which normally takes place in the case of aliphatic aldehydes of the respective aldehydes is largely suppressed. The same applies to the unwanted Heteroaldolreaktion with the unwanted partners.

In the method according to the invention, in particular, only As small as possible amounts of by-products are formed.

Solution:

 This object is achieved by processes for the preparation of aliphatic aldehydes of all formula I.

 dissolved, which is characterized in that an aldehyde of the general formula II

 with an aldehyde of the general formula III

CHO CH ₂ in those

R ^{1 is} hydrogen or a methyl group,

R ^{2 is} a straight-chain or branched alkyl radical having 1 to 4 C atoms and the two X are each hydrogen or together form a further CC bond,

 i) reacting in the presence of an aldol condensation catalyst to the substituted octenal of the general formula I, ii) in the reaction of the two aldehydes a certain molar ratio between II and III complies and

 optional

 iii) optionally hydrogenating it continuously or batchwise to give the corresponding octanal of formula I,

characterized in that the aldehydes of the general formulas III and II in a molar ratio of III: II of between 1.4: 1 and 0.6: 1 be used.

Definition of terms:

 In the context of the present invention, all quantities are, unless stated otherwise, to be understood as weight data.

In the context of the present invention, the term "room temperature" means a temperature of 20 ° C. Unless indicated otherwise, temperature data are in degrees Celsius (° C.).

 Unless stated otherwise, the reactions or process steps given are carried out at normal pressure / atmospheric pressure, i. at 1013 mbar.

Detailed description:

 The invention relates to a process for the preparation of aliphatic aldehyde of the general formula I.

in the

R ^{1 is} hydrogen or a methyl group,

R ^{2 is} a straight-chain or branched alkyl radical having 1 to 4 C atoms, preferably a methyl or ethyl group, and the two X are each hydrogen or together represent a further CC bond, preferably 2,5,7,7- Tetramethyloctanal, 2,4,5,7,7-pentamethyloctanal, 2-ethyl-5,7,7-trimethyloctanal and 2,5,7,7-tetramethyl-2-octene-1-al, especially 2,5,7 , 7-tetramethyloctanal, in which one

an aldehyde of the general formula I I

with an aldehyde of the general formula III CHO

CH ₂ i) in the presence of an aldol condensation catalyst to the substituted octenal of general formula I,

ii) in the reaction of the two aldehydes complies with a certain molar ratio between II and III, and

optional

iii) hydrogenating it continuously or batchwise to the corresponding octanal of formula I,

characterized in that the aldehydes of the general formulas III and II are used in a molar ratio of 111: 11 of between 1.4: 1 and 0.6: 1 and use of the aliphatic aldehydes thus prepared as fragrances.

With regard to the definition of the variable "X" in the general formula I, it should be pointed out in the context of the present invention that these after the actual aldol reaction initially together represent a further CC bond and, after the hydrogenation carried out optionally, in each case for hydrogen According to the present invention, the continuous mode of operation in step iii) is preferred.

The aliphatic aldehydes of the formula I have valuable perfume properties.

Particularly interesting aldehydes of the formula I are those in which R ^{1 is} hydrogen or a methyl group and R ^{2 is} a methyl group or an ethyl group and X is hydrogen. A particularly valuable substance among the preferred compounds is the 2,5,7,7-tetramethyloctanal (formula I, R ¹ = H, R ² = CH ₃ ), the intense yet fine lily of the valley note is particularly interesting and can not be compared to any current market product with this unique grade.

 Accordingly, a preferred embodiment of the present invention is a process for the preparation of 2,5,7,7-tetramethyloctanal.

Because of their interesting odor properties, the aldehydes of the general formula I can be used advantageously as fragrances or constituents of perfume oils for cosmetic or technical applications. They can be used in compositions within a broad concentration range and blend well with common perfume ingredients and other fragrances to create novel compositions. The proportion of aliphatic aldehydes in fragrance compositions can be between 1 and 50% by weight, based on the weight of the composition.

Such compositions can be used for the perfuming of cosmetic preparations, such as creams, lotions, perfumed waters, toilet soaps, mouthwashes, aerosols and in the Extrait perfumery. They can also be used to improve the odor of technical products such as detergents, detergents and softeners. Normally, 0.05 to 2 wt.% Of such a composition, based on the total product used.

In addition to the process for preparing these aliphatic aldehydes of the formula I, it is also the subject of the present invention to use the aldehydes of the formula I prepared by the process according to the invention for imparting, improving or modifying the odor properties of perfumes or perfumed products. The aldehydes of the formulas II and III are commercially available compounds. In particular, the aldehydes of the formula III, such as propionaldehyde, butyraldehyde, isovaleraldehyde, n-valeraldehyde and n-hexanal are important technical intermediates, and are therefore inexpensive in sufficient quantity Available.

In a variant of the present invention, 3,5,5-trimethylhexanal (= isononanal) is used as the preferred aldehyde II.

In a variant of the present invention, propanal is used as the preferred aldehyde III.

In a variant of the present invention, 3,5,5-trimethylhexanal (= isononanal) and propanal are used as preferred compounds of the formulas II and III.

The process according to the invention is based on an aldol reaction (aldol condensation) of the aldehydes of the formulas II and III and subsequent hydrogenation.

In a preferred variant of the present invention, the hydrogenation subsequent to the aldol reaction is carried out continuously, and the product from the aldol condensation is then transferred directly or via a washing and / or distillation stage into the hydrogenation apparatus.

The continuous mode of operation of the process according to the invention offers significant advantages in terms of safety and cost aspects for the industrial production of the compounds mentioned.

The fact that the direct product of the aldol reaction is not isolated, but is processed directly, it is possible to realize a single integrated manufacturing structure for said aliphatic aldehydes. There are therefore no storage costs for the resulting octenals and it must therefore be taken no security precautions in connection with their isolation and / or storage.

Although the aldol reaction is carried out in a conventional manner, in the context of the present invention, however, the stated solvents, catalysts, starting materials and process conditions are essential. In a variant of the present invention, sterically demanding organic bases are used as basic catalysts. In a variant of the present invention, the basic catalysts used are potassium or sodium hydroxide solution, in particular sodium hydroxide solution (5.8% strength).

In a variant of the present invention, suitable solvents are aliphatic, cycloaliphatic and aromatic d-do alcohols, as well as other inert solvents than the basic catalysts used.

In a variant of the present invention, the solvents used are C 1 -C 3 -alcohols, such as methanol or ethanol, in particular methanol.

In a variant of the present invention, solvent mixtures can also be used. The aldol reaction is carried out in a variant of the present invention at elevated temperature, but scarce (about 5 to 10 ° C) below the boiling point of the solvent or solvent mixture, preferably 50 to 60 ° C, and at atmospheric pressure. In a variant of the present invention, the aldol reaction can take place at an overpressure of up to 10 bar.

In a variant of the present invention, the aldehyde of the general formula II is used in excess.

In a variant of the present invention, the aldehyde of the general formula III is used in excess. In a variant of the present invention, the aldehydes of the general formulas III and II are used in a molar ratio of 0.7: 1 to 1: 0.7, preferably in an equimolar ratio. In a variant of the present invention, the aldehydes of the general formulas III and II are used in a molar ratio of between 1.2: 1 and 0.8: 1, preferably in an equimolar ratio.

In the range according to the invention of the molar ratios of the aldehydes 111: 11 between 1.4: 1 and 0.6: 1, surprisingly, a much smaller amount of by-products of the aldol reaction is obtained.

In the case of the reaction of isononanal and propanal, these are, in addition to other non-specific by-products, mainly: 2-methylpentenal, 2,4,7,9,9-pentamethyl-deca-2,4-dienal, 5,7,7 Trimethyl-2- (1,3,3-trimethyl-butyl) oct-2-enal.

In a variant of the present invention, the aldehydes of the general formulas II and III are used in a molar ratio of III: II between 1.4: 1 and 0.6: 1 and the reaction at a temperature of 45 to 55 ° C. in aqueous Reaction medium carried out, in this variant is subsequently preferably adjusted to a pH of 5 to 8.

Even with this procedure, surprisingly fewer by-products are formed. It was not foreseeable for the person skilled in the art that due to the limitation of the molar ratio to the range according to the invention in the Aldol reaction only very small amounts of undesired by-products would be formed. If the radical R ^{1 is} hydrogen, then both both the aldehydes II and the aldehydes II I are unsubstituted in the alpha position, resulting in the formation of a mixture of three different aldol condensation products (a homoaldol condensation of aldehyde II, a homoaldol condensation of aldehyde III and a hetero-aldol condensation).

In a variant of the present invention, the basic catalyst with the solvent (for example methanol) is initially charged and the mixture of aldehydes II and III is added. In this case, the aldehydes II and III can be added either in an inflow, or in separate tributaries.

In a variant of the present invention, the aldehyde III and the basic catalyst are initially charged with solvent and the aldehyde II is added in the form of one or more feeds.

In a variant of the present invention, the aldehyde II and the basic catalyst are initially charged with solvent and the aldehyde III is added in the form of one or more feeds.

In a further variant of the present invention, the aldehydes II and III are initially charged in solvent and then catalyst is added with or without further solvent. The octenals obtained in the aldol reaction are then hydrogenated to the corresponding saturated aldehydes of the formula I.

Palladium catalysts on various supports, such as carbon, alumina, silica gel or bauxite, in particular palladium on activated carbon, have proved particularly suitable for this selective hydrogenation step. Again, lower alcohols are advantageous solvents.

A method which can be used particularly well in the context of the present invention is that described in WO 2004/007414 A1, page 2, line 26 to page 6, line 4, example 1 therein and FIG. 1 for structurally similar compounds (citral to citronellal) ,

A device which is particularly well suited for the purposes of the present invention is disclosed in EP 0 798 039 A2, column 4, line 6 to column 5, line 11, the local examples 1 and 2s, and the local figures 1 to 3 described.

Accordingly, in a variant of the present invention, the hydrogenation process of WO 2004/007414 A1 and / or the reactor described in EP 0 798 039 A2 are used.

The hydrogenation can be carried out in one variant of the present invention.

In this case, 5 to 35 bar, 60 to 250 ° C and a significant excess amount of hydrogen are set in a particularly preferred variant.

In a variant of the present invention, the hydrogenation is carried out at 10 bar overpressure.

In a variant of the present invention, the hydrogenation is carried out in a bubble column.

In a variant of the present invention, the hydrogenation is carried out on a supported palladium catalyst, preferably palladium 0.5% of activated carbon.

In a variant of the present invention, the hydrogenation is carried out at 10 bar overpressure in a bubble column on a supported palladium catalyst, preferably palladium 0.5% of activated carbon.

In one variant of the present invention, the hydrogenation catalyst may be suspended in liquid, in another variant, the hydrogenation catalyst may also be immobilized.

In another variant, the hydrogenation can also be divided into a main hydrogenation and a posthydrogenation. In a preferred variant, 10 to 12 bar, 80 to 85 ° C and a significant excess amount of hydrogen for the main hydrogenation and 20 to 30 bar, 150 to 200 ° C and a significant excess amount of hydrogen for Nachhydierung.

A preferred variant of the present invention is the following process:

 Process for the preparation of aliphatic aldehydes of general formula I

 comprising in the order given a) aldehydes of the general formulas II and III

 optionally together with solvent, preferably methanol and / or ethanol, in particular methanol

 b) presentation of basic catalyst, preferably alkali metal hydroxide, particularly preferably aqueous NaOH, if appropriate together with solvent, preferably methanol and / or ethanol, in particular methanol

 c) mixing the mixture of the aldehydes and the mixture with the catalyst at temperatures of 40 to 80 ° C, preferably 50 to 60 ° C.

 d) maintain at the temperature for 5 to 60 minutes, preferably 10 to 40 minutes

 e1) if appropriate, transferring into a further reaction vessel and adjusting the pH to values between 4 and 10, e2) if appropriate washing with distilled water,

f) optionally distillation, preferably fractional distillation, and optional, if a hydrogenation of the product of the aldol reaction is to take place

 g) continuous or batchwise in a hydrogenation apparatus, preferably hydrogenation autoclave or bubble column, in particular bubble column,

 h) selective hydrogenation of the double bond on a hydrogenation catalyst, preferably palladium catalyst, in particular 0.5% palladium on activated carbon,

 i) optionally purification of the product,

wherein R ¹ , R ² and X are each as defined above,

characterized in that the aldehydes of the general formulas III and II are used in a molar ratio of III: II of between 1.4: 1 and 0.6: 1. The steps e1) and e2) can not be performed either, either or both of them.

In a preferred variant of the present invention, step g) is carried out continuously.

In particular, in the case of the continuous procedure of the inventive method, it is an advantage that unused aldehyde II can be recycled. In a variant of the present invention, it is preferred that the

Method according to the steps of separation and recycling of unconsumed aldehyde II for reuse in the inventive method. In a variant of the present invention, it is preferred that the methods comprise the separation and recycling of unused aldehyde III for reuse in the methods of the invention. In a variant of the present invention, it is preferred that the processes accordingly comprise the separation and recycling of unused aldehydes II and III for reuse in the processes of the invention.

Due to the particular fragrance properties described, the aldehydes prepared by the process according to the invention can advantageously be used as fragrances or constituents of fragrance compositions and perfume oils for cosmetic applications. Of importance is also that they can be easily prepared from readily available starting materials.

If isononanal and propanal are reacted in the context of the present invention, not only the main product DH-Lyrisal but also iso-DH-Lyrisal or, after the hydrogenation, in addition to lyyrisal, iso-Lyrisal can also be formed according to the following scheme.

 Iso-DH-Lyrisal Iso-Lyrisal

The various embodiments of the present invention, e.g. but not exclusively those of the various dependent claims may be combined with each other in any manner.

The invention will now be elucidated with reference to the following nonlimiting examples.

Examples: Example 1 (comparative example)

 In a conventional stirred tank cascade, a mixture consisting of 39% by weight of isononanal; 6.4% by weight of propionaldehyde; 47.5% by weight of methanol; 0.4 wt .-% sodium hydroxide and 6.7 wt .-% water, continuously metered in a feed rate of 1 1, 4 g / min. This corresponded to a molar ratio of propionaldehyde: ionone ion of 0.4: 1. Isononanal and propionaldehyde, as well as methanol, sodium hydroxide and water were premixed separately. After a total run time of 31, 7 min at 50 ° C, the product of the stirred tank cascade in a downstream reactor with acetic acid (80%) was adjusted to pH = 5-8.

 A mixture was obtained which had the following composition: 48.3% by weight of methanol; 0% by weight of propionaldehyde; 0.4% by weight of 2-methylpentenal; 19.3% by weight of isononanal; 15.6% by weight of 2,5,7,7-tetramethyl-oct-2-enal (DH-Lyrisal); 0.1% by weight 2,4,7,9,9-pentamethyl deca-2,4-dienal; 5 wt .-% of 5,7,7-trimethyl-2- (1, 3,3-trimethyl-butyl) -oct-2-enal (NONADI), a proportion of 1 1, 3 wt .-% is based on water and other by-products. The proportion of by-products (NONADI, methylpentenal, 2,4,7,9,9-pentamethyl deca-2,4-dienal) was 0.35 kg per kg of product value DH-Lyrisal. Example 2:

 In a conventional stirred tank cascade, a mixture consisting of 33.6% by weight of isononanal; 1 1% by weight of propionaldehyde; 47.5% by weight of methanol; 0.5 wt .-% sodium hydroxide and 7.4 wt .-% water, metered in continuously at a feed rate of 7.7 g / min. This corresponded to a molar ratio of propionaldehyde: lsononanal of 0.8: 1. Isononanal and propionaldehyde, as well as methanol, sodium hydroxide and water were premixed separately. After a total run time of 46.8 minutes at 50 ° C, the product of the stirred tank cascade in a downstream reactor with acetic acid (80%) was adjusted to pH = 5-8.

A mixture was obtained which had the following composition: 46.9% by weight of methanol; 0.1% by weight of propionaldehyde; 1% by weight of 2-methylpentenal; 9.4% by weight of isononanal; 22.6% by weight of 2,5,7,7-tetramethyl-oct-2-enal (DH-Lyrisal); 0.4% by weight 2,4,7,9,9-pentamethyl deca-2,4-dienal; 5.6% by weight of 5,7,7-trimethyl-2- (1,3,3-trimethyl-butyl) -oct-2-enal (NONADI), 12.9% by weight of water, a content of 1, 1 wt .-% accounts for other by-products. The proportion of by-products (NONADI, methylpentenal, 2,4,7,9,9-pentamethyl-deca-2,4-dienal) was 0.31 kg per kg of valuable product DH-Lyrisal.

Example 3:

 In a conventional stirred tank cascade, a mixture consisting of 31.2% by weight of isononanal; 12.7% by weight of propionaldehyde; 47.5% by weight of methanol; 0.5% by weight of sodium hydroxide and 8.1% by weight of water, metered in continuously at a feed rate of 7.4 g / min. This corresponded to a molar ratio of propionaldehyde: lsononanal of 1: 1. Isononanal and propionaldehyde, as well as methanol, sodium hydroxide and water were premixed separately. After a total run time of 49.4 min at 50 ° C, the product of the stirred tank cascade in a downstream reactor with acetic acid (80%) was adjusted to pH = 5-8.

 A mixture was obtained which had the following composition: 47.5% by weight of methanol; 0% by weight of propionaldehyde; 1.5% by weight of 2-methylpentenal; 7% by weight of isononanal; 23.1% by weight of 2,5,7,7-tetramethyl-oct-2-enal (DH-Lyrisal); 0.6% by weight 2,4,7,9,9-pentamethyl deca-2,4-dienal; 4.9 wt .-% 5,7,7-trimethyl-2- (1,3,3-trimethyl-butyl) -oct-2-enal (NONADI), 13.7 wt .-% water, a proportion of 1, 7 wt .-% accounts for other by-products. The proportion of by-products (NONADI, methyl pentenal, 2,4,7,9,9-pentamethyl deca-2,4-dienal) was 0.30 kg per kg value product DH-Lyrisal.

Example 4:

In a conventional stirred tank cascade, a mixture consisting of 28.8% by weight of isononanal; 14.1% by weight of propionaldehyde; 47.5% by weight of methanol; 0.6 wt .-% sodium hydroxide and 9 wt .-% water, metered in continuously at a feed rate of 7.3 g / min. This corresponded to a molar ratio of propionaldehyde: lsononanal of 1.2: 1. Isononanal and propionaldehyde, as well as methanol, sodium hydroxide and water were separated premixed. After a total run time of 49.7 min at 50 ° C, the product from the stirred tank cascade in a downstream reactor with acetic acid (80%) was adjusted to pH = 5-8.

 A mixture was obtained which had the following composition: 47.5% by weight of methanol; 0.1% by weight of propionaldehyde; 2.1% by weight of 2-methylpentenal; 5.4% by weight of isononanal; 22.1% by weight of 2,5,7,7-tetramethyl-oct-2-enal (DH-Lyrisal); 0.4% by weight 2,4,7,9,9-pentamethyl deca-2,4-dienal; 4.2% by weight of 5,7,7-trimethyl-2- (1,3,3-trimethyl-butyl) -oct-2-enal (NONADI), a proportion of 18.2% by weight being accounted for Water and other by-products. The proportion of by-products (NONADI, methylpentenal, 2,4,7,9,9-pentamethyl deca-2,4-dienal) was 0.30 kg per kg value product DH-Lyrisal.

Example 5:

 In a conventional stirred tank cascade, a mixture consisting of 26.8% by weight of isononanal; 15.3% by weight of propionaldehyde; 47.5% by weight of methanol; 0.6 wt .-% sodium hydroxide and 9.8 wt .-% water, metered in continuously at a feed rate of 7.4 g / min. This corresponded to a molar ratio of propionaldehyde: ionone ion of 1.4: 1. Isononanal and propionaldehyde, as well as methanol, sodium hydroxide and water were premixed separately. After a total run time of 48.6 minutes at 50 ° C, the product of the stirred tank cascade in a downstream reactor with acetic acid (80%) was adjusted to pH = 5-8.

 A mixture was obtained which had the following composition: 46.8% by weight of methanol; 0.1% by weight of propionaldehyde; 2.7% by weight of 2-methylpentenal; 4.3% by weight of isononanal; 22.4% by weight of 2,5,7,7-tetramethyl-oct-2-enal (DH-Lyrisal); 0.7% by weight 2,4,7,9,9-pentamethyl deca-2,4-dienal; 4.3 wt .-% 5,7,7-trimethyl-2- (1, 3,3-trimethyl-butyl) -oct-2-enal (NONADI), a share of 18.7 wt .-% accounts for Water and other by-products. The proportion of by-products (NONADI, methylpentenal, 2,4,7,9,9-pentamethyl deca-2,4-dienal) was 0.35 kg per kg of product value DH-Lyrisal.

Example 6 (Comparative Example)

In a conventional stirred tank cascade was a mixture consisting of 22.1% by weight of isononanal; 18.1% by weight of propionaldehyde; 47.5% by weight of methanol; 0.7 wt .-% sodium hydroxide and 1 1, 6 wt .-% water, continuously metered in at a feed rate of 7.4 g / min. This corresponded to a molar ratio of propionaldehyde: lsononanal of 2: 1. Isononanal and propionaldehyde, as well as methanol, sodium hydroxide and water were premixed separately. After a total run time of 43.3 minutes at 50 ° C, the product from the stirred tank cascade in a downstream reactor with acetic acid (80%) was adjusted to pH = 5-8.

A mixture was obtained which had the following composition: 45.8% by weight of methanol; 0.3% by weight of propionaldehyde; 4.5% by weight of 2-methylpentenal; 2.5% by weight of isononanal; 19.4% by weight of 2,5,7,7-tetramethyl-oct-2-enal (DH-Lyrisal); 0.9% by weight 2,4,7,9,9-pentamethyl deca-2,4-dienal; 3.7% by weight of 5,7,7-trimethyl-2- (1,3,3-trimethyl-butyl) -oct-2-enal (NONADI), 15.4% by weight of water, a content of 7.5% by weight is accounted for by other by-products. The proportion of by-products (NONADI, methylpentenal, 2,4,7,9,9-pentamethyl deca-2,4-dienal) was 0.47 kg per kg of product DH-Lyrisal.

Example 7:

After washing with water in countercurrent, the organic phase was separated from Examples 1 to 6 and worked up by distillation. This gave a feed fraction, which was mixed with methanol and continuously introduced into a bubble column, where then in the presence of 25 g of a 0.5% palladium / activated carbon catalyst at 80 ° C at a hydrogen pressure of 10 bar, hydrogenated. The hydrogenation time was 10 hours. After filtering off the catalyst, 2,5,7,7-tetramethyloctanal was obtained by fractional distillation.

Example 8:

The product of Examples 1 to 6 was passed directly into a hydrogenation plant, wherein the hydrogenation was divided into a main and a subsequent subsequent hydrogenation, wherein the discharge from the main hydrogenation directly into the post-hydrogenation, without further work-up or isolation was driven.

 The main hydrogenation was carried out in a bubble column on a 0.5% palladium / carbon catalyst at 10 to 12 bar, 80 to 85 ° C and a significant excess amount of hydrogen and the post-hydrogenation in a bubble column on a 0.5% palladium / activated carbon catalyst at 20 to 30 bar, 150 to 200 ° C and a significant excess amount of hydrogen.

Example 9:

 The procedure was carried out as in Example 8, it was only interposed between the aldol condensation and the hydrogenation, a washing with acetic acid and distilled water and a fractional distillation.

Example 10 (comparative example analogous to Example 1 of EP 0 252 378 A1):

192.0 g (6 mol) of methanol and 3.1 g (0.075 mol) of NaOH were placed under nitrogen in a reaction flask and heated to boiling. Subsequently, a mixture of 214.0 g (1.5 mol) of isononanal and 174.3 g (3.0 mol) of propanal was added dropwise within 10 minutes. The reaction mixture was heated at reflux for 60 minutes. It was then adjusted to pH = 5 with acetic acid (80%). After phase separation, the organic phase (485 g) was analyzed with the desired product. A mixture was obtained which had the following composition:

 24.07% by weight of methanol; 0.13% by weight of propionaldehyde; 5.94% by weight of 2-methylpentenal; 1.16% by weight of isononanal; 36.21% by weight of 2,5,7,7-tetramethyl-oct-2-enal (DH-Lyrisal); 4.14% by weight 2,4,7,9,9-pentamethyl deca-2,4-dienal; 3.04% by weight of 5,7,7-trimethyl-2- (1,3,3-trimethyl-butyl) -oct-2-enal (NONADI). The shortfall of 25.31 wt .-% accounts for a large number of unclarely characterized by-products. The proportion of by-products (NONADI, methylpentenal, 2,4,7,9,9-pentamethyl-deca-2,4-dienal) was 0.36 kg per kg of valuable product DH-Lyrisal.

Claims

 Process for the preparation of aliphatic aldehydes Claims: 1 Process for the preparation of aliphatic aldehydes of the general formula I

 characterized in that an aldehyde of the general formula II

 with an aldehyde of the general formula  CHO CH ₂  I. in those R ^{1 is} hydrogen or a methyl group, R ^{2 is} a straight-chain or branched alkyl radical having 1 to 4 C atoms and the two X are each hydrogen or together form a further CC bond,  i) reacting in the presence of an aldol condensation catalyst to the substituted octenal of the general formula I, ii) in the reaction of the two aldehydes a certain molar ratio between II and III complies  optional  iii) hydrogenating it continuously or batchwise to the corresponding octanal of formula I, characterized in that the aldehydes of the general formulas III and II in a molar ratio of 111: 11 of between 1.4: 1 and 0.6: 1. Process for the preparation of aliphatic aldehydes of the general

Formula I

comprising in the order given  a) Preparation of aldehydes of the general formulas II and

 optionally together with solvent,  b) presentation of basic catalyst, if appropriate together with solvent,  c) mixing the mixture of the aldehydes and the mixture with the catalyst at temperatures of 40 to 80 ° C,  d) keep at the temperature for 5 to 60 minutes,  e1) optionally converting into a further reaction vessel and Adjusting the pH to values between 4 and 10, e2) optionally washing with distilled water,  f) optionally distillation, and  optional, if a hydrogenation of the product of the aldol reaction is to take place,  g) continuous or batchwise transfer to a hydrogenation apparatus,  h) selective hydrogenation of the double bond on a hydrogenation catalyst,  i) optionally purification of the product, wherein R ^{1 is} hydrogen or a methyl group, R ^{2 is} a straight-chain or branched alkyl radical having 1 to 4 C atoms and the two X are each hydrogen or together form a further CC bond,  characterized in that the aldehydes of the general formulas III and II are used in a molar ratio of III: II of between 1.4: 1 and 0.6: 1. 3. The method according to claim 1, characterized in that step iii) is carried out continuously. 4. The method according to claim 2, characterized in that step g) is carried out continuously. 5. The method according to any one of claims 1 to 4, characterized in that the reaction is carried out at a temperature of 45 to 55 ° C in aqueous reaction medium and preferably subsequently adjusted to a pH of 5 to 8. 6. The method according to any one of claims 1 to 5, characterized in that the aldehydes of the general formulas III and II in a molar ratio of III: II of between 1.2: 1 and 0.8: 1, are used. 7. The method according to any one of claims 1 to 6, characterized in that it comprises the separation and recycling of unused aldehyde II and / or III. 8. The method according to any one of claims 1 to 9, characterized in that 3,5,5-trimethylhexanal is used as the compound of formula II. 9. The method according to any one of claims 1 to 9, characterized in that propanal is used as the compound of formula III. 10. The method according to any one of claims 1 to 9, characterized in that 3,5,5-Trimethylhexanal and propanal are used as compounds of the formulas II and III. 1 1. Use of the aldehydes of the formula I prepared by means of one of the processes according to one of Claims 1 to 10 for imparting, improving or modifying the odor properties of perfumes or perfumed products.