JPS5846509B2 - New 2-methylene-3-substituted butanal and its production method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides two novel compounds, 2-methylene-3-(4-methylcyclohex-3-enyl)-butanal and 2-methylene-3-(4-methylcyclohex-3-enyl)-butanal.
Concerning methylene-3-(4-methylcyclohexyl)-butanal.

The production of methylene aldehyde can be carried out in various ways.

According to the Mannich reaction, ammonia or primary or secondary
grade amine (which is usually present as a salt e.g. hydrochloride)
is reacted with formaldehyde and a compound containing a reactive hydrogen atom.

According to the method described in US Pat. No. 2,518,416, a mixture of an aldehyde and formaldehyde having one CH2 group at the α-position relative to the carbonyl group is mixed into a melt of a salt of a primary or secondary amine and a strong acid. I am passing through.

Furthermore, piperidine hydrochloride, morpholine hydrochloride or ammonium salts such as ammonium chloride have also been used for the condensation of aliphatic aldehydes and formaldehyde (see US Pat. No. 2,639,295).

The new process described in West German Patent Application No. P2855505.7 involves reacting aldehydes with formaldehyde in the presence of catalytic amounts of enamines to produce 2-methylene aldehyde.

This method of operation is economically advantageous compared to known methods;
It has been found that this method can be easily carried out industrially.

By hydroformylation, limonene (1-methyl-4
-isopropenyl-cyclohex-1-ene) can be easily converted to 3-(4-methylcyclohex-3-enyl)-butanal.

The reaction of olefinically unsaturated compounds with carbon monoxide and hydrogen can be carried out in a variety of ways, depending on the type of catalyst used.

For example, it is known to use as catalysts cobalt carbonyl compounds which, in addition to carbon monoxide, additionally contain trialkyl or triarylphosphines as ligands, or to operate in the presence of rhodium carbonyl complexes.

In particular using rhodium carbonyl which additionally contains triphenyl or trialkylphosphine,
It has been particularly effective to use a pressure of 50 bar and a temperature of 110-160°C (West German Patent Application No. 228
37480).

Starting from 3-(4-methylcyclohex-3-enyl)butanal, methylation with formaldehyde gives 2-methylene-3-(4-methylcyclohex-3-enyl)-butanal. It will be done.

Reaction of the product of partial hydrogenation of 3-(4-methylcyclohex-3-enyl)-butanal with formaldehyde yields 2-methylene-3-(4-methylcyclohexyl)-butanal.

Both aldehydes are prepared by known methods.

3-(4-Methylcyclohex-3-enyl)-butanal is reacted with formaldehyde in the presence of a catalytic amount of a secondary amine, preferably di-n-butylamine.

In this way, 2-methylene-3-(4-methylcyclohex-3-enyl)-phthanal is obtained directly.

2-Methylene-3-(4-methylcyclohexyl)-butanal is obtained in a similar manner but after a previous partial hydrogenation of the starting aldehyde.

For the production of 2-methylene-3-(4-methylcyclohex-3-enyl)-butanol, 3-(4-methylcyclohex-3-enyl)-butanal and formaldehyde were combined in a molar ratio of 1:1. Use with.

A small excess of 10,000 of both components is harmless but unnecessary.

Formaldehyde can be used as a pure compound or as a solution in a suitable solvent such as water.

Instead of formaldehyde, it is also possible to start from compounds which form formaldehyde under certain conditions, such as condensation products of formaldehyde, such as paraformaldehyde.

Secondary amines are used as catalysts, which may contain the same or different alkyl groups.

Examples are N-ethyl-n-7'thylamine, N-propyl-n-pentylamine or N-ethyl-cyclohexylamine.

Particularly effective is di-n-butylamine.

0.01 secondary amine per 11 moles of formaldehy
~0.05 mol, especially 0.02 mol is used.

The reaction is carried out at 60-120°C and especially 80-100°C.

To carry out the methylenation, 3-(4-methylcyclohex-3-enyl)-butanal is reacted directly with formaldehyde or formaldehyde-forming substances in the presence of a catalyst.

The presence of a solvent such as water or an alcohol (eg inbutanol or 2-ethylhexanol) is advantageous.

The reaction products are isolated by fractional distillation.

The compounds are obtained in a form that can be used directly as final product.

Partial hydrogenation of 3-(4-methylcyclohex-3-enyl)-butanal gives 3-(4-methylcyclohexyl)-butanal.

The reaction with hydrogen is usually carried out in a pressurized vessel in the presence of a catalyst.

using a pressure of 1 to 150 bar depending on the type of catalyst;
Maintain temperature between 20-120°C.

Suitable hydrogenation catalysts include noble metals such as palladium and platinum.

Palladium catalysts are particularly effective.

It is advantageous to use the catalyst in a concentration of 0.5 to 2 parts by weight, based on the aldehyde used.

The hydrogenation can be carried out with the addition of a solvent, but its presence is also not absolutely necessary.

To obtain pure Itl of 3-(4-methylcyclohexyl)-butanal, the crude product is distilled after separation of the catalyst.

The preparation and isolation of 2-methylene-3-(4-methylcyclohexyl)-butanal is carried out analogously to 2-methylene-3-(4-methylcyclohex-3-enyl)-butanal described above.

The new α-methylene aldehydes are of particular interest as perfumes, having an odor that differs from other commercially available perfumes in their properties.

Another advantage of the new aldehyde is that it can be prepared on the basis of the inexpensive and abundantly available starting material limonene.

Next, the aldehydes of the present invention will be explained in detail with reference to Examples.

Example 1 2-Methylene-3-(4-methylcyclohex-3-enyl)-butanal 3-(4-methylcyclohex-3-enyl)butanal 332. ! i', 30% formaldehyde solution 211
and 13 g of di-n-butylamine are heated in a flask to a maximum of 70° C. for 30 minutes with stirring and cooling to reflux.

After separation of the aqueous phase, the crude product is isolated and, after gas chromatographic analysis, contains 94 ml of 2=methylene compound along with about one or more starting aldehydes.

311 g of 99.4% pure aldehyde are isolated by distillation (boiling point 112° C./13 melibar).

Example 2 Preparation of 2-ethylene-3-(4-methylcyclohexyl)-butanal 3-(4-methylcyclohexyl)-butanal 336
g, 30% formaldehyde aqueous solution 210.9 and di-
13 g of n-butylamine are reacted under the conditions of Example 1.

After gas chromatographic analysis, the crude product contains 95% of the 2-methylene compound with 1% of the starting aldehyde.

99.1% pure aldehyde by distillation 320. ! i+ is isolated (boiling point 110°C/13 mbar).

Claims (1)

[Claims] 1 Formula: 2-methylene-3 monosubstituted-butanal 22-methylene-3-(4-methylcyclohexe-3-
32-Methylene-3-(4-methylcyclohexyl)-, which is 2-methylene-3-(4-methylcyclohexyl)-
The compound 43-(4-methyl-cyclohex-3-enyl)-butanal of claim 1, which is butanal, is mixed with formaldehyde or a formaldehyde-forming compound in the presence of a contact amount of a secondary amine from 60 to 120 hours. ℃
2-methylene-3-(4
-Production of methyl-cyclohex-3-enyl)-butanal 53-(4-Methyl-cyclohex-3-enyl)-butanal is partially hydrogenated in advance to form 3-(4-methylcyclohexyl)-butanal, and then contacted. 2-methylene-3-(4-methyl-cyclohexyl)-, characterized in that it is reacted with formaldehyde or a formaldehyde-forming compound at 60-120°C in the presence of an amount of a secondary amine.
Butanal manufacturing method