DE10241321A1 - Production of dialkylamino ether comprises reaction of a dialkyamino alcohol or a dialkylamino glycol to form a dialkylamino alcoholate and reaction with acetylene to form the vinyl ether compound followed by hydrogenation - Google Patents

Abstract

A process for the production of dialkylaminoethers comprises reaction of a dialkyaminoalcohol and/or a dialkylaminoglycol to form a dialkylaminoalcoholate and reaction with acetylene to form the vinyl ether compound followed by hydrogenation. A process for the production of dialkylaminoethers of formula (1) comprises reaction of a dialkyaminoalcohol and/or a dialkylaminoglycol of formula (2) to form a dialkylaminoalcoholate of formula (3) and reaction with acetylene to form the vinyl ether compound of formula (4) followed by hydrogenation. (R1)(R2)N-X-O-CH2-CH3 (1) (R1)(R2)N-X-OH (2) (R1)(R2)N-X-OM (3) (R1)(R2)N-X-O-CH=CH2 (4) R1, R2 = 1-10C alkyl, 5-8C cycloalkyl, 6-10C aryl or 7-15C aralkyl or R1 and R2 together form a 4-7 C ring containing 1 or 2 oxygen atoms in the form of ether linkages; X = 1-5C hydrocarbon or Y-O-Z-; and Y, Z = -CH2-CH2-, -CH2CH(CH3)- and/or -CH2CH2CH2-

Description

The invention relates to a Process for the preparation of dialkylamino ethers by reaction with acetylene and hydrogenation.

1-Alkoxy- (omega) dialkylamino alkanes are known. For example, in the US 4,588,843 describes the preparation of such compounds starting from β-dialkylaminoalkanols. The alkanol is converted into the alcoholate using NaOH / KOH and the subsequent reaction is carried out using alkyl halides. Working up the product from the aqueous phase by extraction with ether is very complex and only yields of the order of 37%.

An improved process for the preparation of 1-alkoxy- (omega) -dialkylaminoethanes is in the EP 0518013-A2 disclosed. The process is characterized in that β-dialkylaminoethanol is prepared with sodium or potassium alcoholates of monohydric alcohols with complete removal of the simple alcohol. The complete removal of the monohydric alcohol can be carried out by distillation together with inert solvents, such as aliphatic or aromatic hydrocarbons. In the second step, the resulting β-dialkylaminoalkali ethanolate is reacted with alkyl halides at elevated temperatures, followed by the pure distillation of the target product with the prior addition of Na / K alcoholate.

Disadvantages of these manufacturing routes are based on a classic Williamson ether synthesis Use of ecological questionable halides and the accumulation of larger quantities of salt freight, what from economic and ecological considerations is disadvantageous.

The object of the present invention is to provide an improved process that is free of the disadvantages described and that it allows in particular 1-Ethoxy- (omega) -dialkylaminoalkanes free from environmentally hazardous by-products and manufacture with high sales.

• – ein Dialkylaminoalkohol bzw. Diaminoglykol der allgemeinen Formel (R¹)(R²)-N-X-OH mit Acetylen in einen Dialkylaminovinylether gemäß folgender Formel (R¹)(R²)-N-X-O-CH=CH₂ überführt wird, und
• – anschließend durch Hydrieren zum Dialkylaminoether der Formel (R¹)(R²)-N-X-O-CH₂-CH₃

umgesetzt wird.Such a method was surprisingly found. The invention relates to a process for the preparation of dialkylaminoethers of the general formula (R ¹ ) (R ² ) -NXO-CH ₂ -CH ₃
wherein
R ¹ , R ² independently of one another for alkyl radicals with 1 to 10, preferably 1 to 4 carbon atoms, cycloalkyl radicals with 5 to 8, preferably 5 to 6 carbon atoms, aryl radicals with 6 to 10, preferably 6 carbon atoms, and for aralkyl radicals with 7 to 15, preferably 7 to 9 carbon atoms, or R ¹ and R ^{2 form} a ring with 4 to 7 carbon atoms and optionally 1 or 2 oxygen atoms in the form of ether bonds, and
X represents a C1 to C5 hydrocarbon radical, preferably a saturated hydrocarbon radical or -YOZ-, with Y and Z independently of one another -CH ₂ CH ₂ -, -CH ₂ CH (CH ₃ ) - and / or -CH ₂ CH ₂ CH ₂ - is characterized in that

• - A dialkylamino alcohol or diaminoglycol of the general formula (R ¹ ) (R ² ) -NX-OH with acetylene in a dialkylaminovinyl ether according to the following formula (R ¹ ) (R ² ) -NXO-CH = CH ₂ is transferred, and
• - Then by hydrogenation to the dialkylamino ether of the formula (R ¹ ) (R ² ) -NXO-CH ₂ -CH ₃

is implemented.

• 1. Überführung eines Dialkylaminoalkohols bzw. Dialkylaminoglykols der Formel (R¹)(R²)N-X-OH in ein Alkoholat (R¹)(R²)N-X-OM
• 2. Umsetzung des Alkoholates mit Acetylen zum entsprechenden Dialkylaminovinylether (R¹)(R²)-N-X-O-CH=CH₂
• 3. Hydrierert des gewonnenen Dialkylaminovinylethers zum gewünschten Produkt (R¹)(R²)N-X-O-CH₂-CH₃

The process according to the invention is essentially divided into 3 process steps:

• 1. Conversion of a dialkylamino alcohol or dialkylaminoglycol of the formula (R ¹ ) (R ² ) NX-OH into an alcoholate (R ¹ ) (R ² ) NX-OM
• 2. Implementation of the alcoholate with acetylene to the corresponding dialkylaminovinyl ether (R ¹ ) (R ² ) -NXO-CH = CH ₂
• 3. Hydrogenates the dialkylaminovinyl ether obtained to the desired product (R ¹ ) (R ² ) NXO-CH ₂ -CH ₃

The course of the reaction is schematic and without being bound by the theory in the reaction scheme in 1 shown.

Preferred embodiments are the subject of subclaims or are shown below.

In a special embodiment can the reaction steps are carried out in succession without the reaction mixture must be cleaned between the individual reaction steps.

Process step 1:

The conversion of the dialkylamino alcohols or dialkylaminoglycols of the formula (R ¹ ) (R ² ) NX-OH used in the corresponding alcoholates can be carried out in different ways.

One way is to use the Dialkylamino alcohols or dialkylaminoglycols with e.g. Alkali / alkaline earth metals to implement in substance. For this purpose, the dialkylamino alcohol or Dialkylaminoglycol directly with preferably sodium or potassium, particularly preferably potassium. The alkali / alkaline earth metals 0.1 to 50 mol%, preferably between 1 and 30 mol%, based on the hydroxyl groups of the dialkylamino alcohol or dialkylaminoglycol used at the beginning of the reaction. The implementation is preferred at temperatures from 10 to 60 ° C.

A preferred method of production is to use the corresponding metal alcoholates, such as alkali / alkaline earth metal alcoholates, instead of the metals and to remove the alcohol released during the reaction by distillation. Alcoholates of short-chain alcohols with 1 up to 6 carbon atoms, optionally linear or branched alkanolates, such as sodium / potassium alcoholates of monohydric alcohols such as methanol, ethanol, propanol, isopropanol, butanol etc.

The potassium salts of are particularly preferred Methanol and ethanol, especially potassium methoxide, as these in the alcoholates formed have good solubility and not tend to separate. The complete removal of the alcohol is preferably done under vacuum.

Should the second reaction step with an inert solvent carried out there is also the possibility to carry out the alcoholate formation in the same inert solvent. The The amount of alcoholate used can vary between 0.1 and 50 mol%, based on the starting material (dialkylamino alcohol or dialkylaminoglycol). The use concentration is preferably 1 to 30 mol%.

Process step 2:

In the next reaction step, acetylene is introduced into the salt of the dialkylamino alcohol or dialkylaminoglycol formed ((R ¹ ) (R ² ) NX-OM). This reaction step takes place at temperatures of 80-280 ° C, preferably 120-180 ° C up to almost complete starting material conversion. The dialkylaminovinyl ether obtained can now be further purified by distillation or separated from the inert solvent before it is hydrogenated to product in process step 3. In principle, the dialkylaminovinyl ether can also be fed to the hydrogenation without further purification, ie in the inert solvent. Acetylene is preferably used in a molar excess.

Depending on the compound used (dialkylamino alcohol or dialkylaminoglycol (R ¹ ) (R ² ) NX-OH) or depending on the corresponding boiling point of the product and / or depending on the solubility of the alcoholate in the dialkylaminovinyl ether, it may be advantageous to carry out this reaction step in a high-boiling point to carry out inert organic solvents.

As a typical representative of this solvent class the following examples may be mentioned: diglyme, triglyme, tetraglyme or polyethylene glycol dialkyl ether, sulfolane, ditolyl ether, tetratoluene, Diphenyl ether. In principle, all solvents that come into consideration in relation to the above Reactions are inert and over have high boiling points, the boiling points are preferably greater than 200 ° C at normal pressure.

Another variant of the method according to the invention consists in a continuous reaction sequence such that after reaching a turnover of 80 to 99% continuously fresher Dialkylamino alcohol or dialkylaminoglycol to the reaction medium is metered in and at the same time the dialkylaminovinyl ether formed is removed from the reaction mixture by distillation. This happens with continuous metering of acetylene. Another feed In principle, no alcoholate is required. The catalyst (the alcoholate) is characterized by a good service life. Still recommends longer Service life or if there is a significant loss of activity, the catalyst to add successively.

In principle, the dialkylaminovinyl ether formed worked up before the further reaction or purified by distillation and the solvent and alcoholate are separated. Basically, however, is also one Further processing possible without any insulation.

Process step 3:

The transfer of the dialkylaminovinyl ether into the final product is done by hydrogenation. The hydrogenation step can are carried out in methods known from the prior art, see for example Ullmanns Encyclopedia, Vol A13, pp. 487-497.

The reaction of the dialkylaminovinyl ether with hydrogen over a supported hydrogenation catalyst is preferred. Precious metals such as palladium, platinum or rhodium are generally suitable as catalysts. Non-noble metals such as nickel, iron, tantalum, chromium and tungsten can also be used as hydrogenation catalysts. Supported catalysts are preferably used. Examples of carrier materials are: alumina, aluminum oxide (in the various modifications α, η and / or γ), silicon dioxide, carborundum, zirconium dioxide, titanium dioxide, BaCO ₃ , CaCO ₃ , ZnO, MgO or activated carbon. The carriers generally contain 0.1 to 5% by weight of metal. A palladium catalyst supported on alumina or activated carbon is particularly preferred.

It is preferred to carry out the Hydrogenation reaction on a fixed bed contact. Here, the educt flow is over a filled with catalyst Guided catalyst bed. This usually takes the form of a cycle. The reaction takes place at temperatures from 50 to 250 ° C and press from 1 to 100 bar. The reaction under low pressure conditions is preferred, i.e. when pressed from 5 to 50 bar and temperatures from 50 to 150 ° C.

Basically, the reaction can also on corresponding powder catalysts in the form of a suspension catalysis carried out become. Technically, this can e.g. in a packed bubble column reactor respectively. However, it is also possible to use such Reactions in a stirred To carry out a batch reactor. After the reaction has taken place, the catalyst is separated off by filtration. In principle, the product can also be separated off by distillation, where the reaction sump is charged with fresh educt and one hydrogenation carried out again becomes.

Depending on the specific requirement pro fil the end product obtained can still be distilled in order to achieve particularly high purities.

Examples

Example 1.1

The reaction was carried out in an apparatus according to 2 , 178 g (2 mol) of 2-dimethylaminoethanol and 500 g of tetraethylene glycol dimethyl ether were placed in a 1 liter four-necked flask. Nitrogen was introduced through a glass frit and 8 g (0.2 mol) of potassium were introduced at 40 ° C. with stirring. After the formation of alcoholate was complete, the changeover to acetylene at 150 ° C. was 50 l / h. After a reaction time of 6 hours, the dimethylaminoethanol was completely converted. The dialkylaminovinyl ether was separated by distillation from the tetraethylene glycol dimethyl ether and from the dialkylamino alcoholate, conversion about 100%.

Example 1.2

445 g (5 mol) of 2-dimethylaminoethanol and 1000 g of ditolyl ether were placed in a 4 liter four-necked flask. Over a Glass frit was introduced with nitrogen and 17.5 g (0.25 mol) of potassium methoxide 40 ° C stirred. The full Alcoholate formation took place by separating off the methanol by distillation at 140 ° C / 30 mbar.

Vinylation took place at 150 ° C at 50 l / h acetylene. After sales of 90% were the same Space-time yield continuously (75 ml / h) 1300 g of 2-dimethylaminoethanol metered in and the dialkylaminovinyl ether via a packed column and reflux divider decreased, yield: approx. 100%, conversion: approx. 95%.

Example 2.1

The prepared according to Example 1.1 Dialkylaminovinylether were in a circulation apparatus on a Fixed bed catalyst (0.5% Pd / Alox; DMT-Engelhard contact) at 100–130 ° C and 10 hydrogenated up to 25 bar hydrogen, yield: approx. 100%, conversion: approx. 100%.

Example 2.2

For hydrogenation in a stirred autoclave 250 g of the dialkylaminovinyl ether according to Example 1.2 in 500 ml of cyclohexane added. In the 1 liter car claw the solution was hydrogen at 110 ° C / 40 bar hydrogenated with a Pd powder catalyst (2% Pd / A carbon), yield: approx. 100%, turnover: approx. 100%.

Claims (11)

Process for the preparation of dialkylaminoethers of the general formula (R ¹ ) (R ² ) -NXO-CH ₂ -CH ₃ wherein R ¹ , R ² independently of one another represent alkyl radicals having 1 to 10 carbon atoms, cycloalkyl radicals having 5 to 8 carbon atoms, aryl radicals having 6 to 10 carbon atoms, and aralkyl radicals having 7 to 15 carbon atoms, or R ¹ and R ^{2 are} a ring with 4 to 7 carbon atoms and optionally 1 or 2 oxygen atoms in the form of ether bonds, and X represents a C1 to C5 hydrocarbon radical, preferably a saturated hydrocarbon radical or -YOZ- with Y and Z independently of one another -CH ₂ CH ₂ - , -CH ₂ CH (CH ₃ ) - and / or -CH ₂ CH ₂ CH ₂ -, characterized in that - a dialkylamino alcohol or dialkylaminoglycol of the general formula (R ¹ ) (R ² ) -NX-OH - In a dialkylamino alcoholate compound of the general formula (R ¹ ) (R ² ) -NX-OM , in which M stands for a metal, is converted, and with acetylene to ( R ¹ ) (R ² ) -NXO-CH = CH ₂ is implemented, and - subsequent hydrogenation of the dialkylaminovinyl ether. A method according to claim 1, characterized in that R ¹ and R ² are CH ₃ . Procedure according to a or more of the preceding claims, characterized in that the dialkylamino alcoholate compound by reaction with alkali or alkaline earth metals or alkali or alkaline earth alcoholates 1 to 6 carbon atoms, preferably sodium or potassium alcoholates or sodium or potassium is produced. Procedure according to a of the preceding claims, characterized in that the reaction with acetylene at temperatures from 80 to 280 ° C, preferably 120 to 180 ° C, is carried out. Procedure according to a of the preceding claims, characterized in that the reaction with acetylene in one inert solvents is carried out with a boiling point greater than 200 ° C. Method according to claim 6, characterized in that the solvent is selected from the group consisting of tetraethylene glycol dimethyl ether and ditolyl ether. Procedure according to a or more of the preceding claims, characterized in that the reaction with acetylene is carried out continuously. Method according to one or more of the preceding claims, characterized in that the hydrogenation is carried out on a supported or unsupported hydrogenation catalyst. Method according to claim 8, characterized in that the hydrogenation catalyst is selected from the group consisting of palladium, platinum, rhodium, nickel, Iron, tantalum, chrome and tungsten. Procedure according to a or more of the claims 1 to 7, characterized in that the hydrogenation catalyst supported on alumina or activated carbon Palladium catalyst is. Procedure according to a or more of the preceding claims, characterized in that the hydrogenation at temperatures between 50 and 250 ° C, preferably 50 and 150 ° C, carried out becomes.