DE975081C - Process for the preparation of alkylidene diethers - Google Patents

Description

The invention relates to the production of alkylidene dieters, which in the alkylidene radical at least Contains 5 carbon atoms by reacting vinyl ethers with acetals including ketals in Presence of an anhydrous, acidic reacting condensation agent, with the as the parent substance The aldehyde used or the ketone used as the parent substance contains at least 3 carbon atoms.

Alkylidene diethers and ether esters, which contain 4 carbon atoms in the alkylidene radical, are so far been prepared that vinyl ethers were reacted with acetals of acetaldehyde. From this reaction it was believed that a hydrogen atom of the methyl group of the alkylidene radical was attached to the methylene group of the vinyl ether migrates.

The assumed reaction equations, possibly with condensation of the vinyl ether, are in U.S. Patent 2,165,962, p. 1, left column, specified.

It has now been shown that instead of the previously ao assumed migration of a hydrogen atom, the reaction is the migration of one of the alkoxy groups of the acetal causes the reaction of a vinyl ether with an acetal of an aldehyde or Ketones, which contain at least 3 carbon atoms, result in a new type of alkylidene diether. If z. B. brings vinyl methyl ether to reaction with dimethylbutyral, you get a product with straight Chain (1,1,3-trimethoxyhexane) in place of the link with a branched chain (1,1-dimethoxy-

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2 - «- methoxyethylbutane), which according to the previously known Reactions of this type were to be expected. That this is correct and that the course of the reaction the migration of an alkoxy group could mean with the type of reactants that have hitherto been used have been used for this implementation cannot be determined. These connections were all alkoxy groups present are identical to one another, and if an acetal of acetaldehyde is among them Prerequisites is brought to implementation with a vinyl methyl ether, the result is the same Alkylidene dieters, regardless of the reaction mechanism.

The reaction mechanism in the preparation of the novel alkylidene dieters according to the invention and the typical reaction components for this are shown in the following equation:

OR ²

+ n CHR ³ = CR ⁴ - OR ² C - / CHR ³ -CR ⁴ \ OR ²

R ¹

OR ²

wherein; C is a divalent hydrocarbon radical Ri '

with at least 3 carbon atoms, R is a hydrocarbon ^{radical, R 1 is} hydrogen or a hydrocarbon ^{radical, R 2 is} the radical of a hydrocarbon, preferably a lower aliphatic, R ³ and R ^{4 is} hydrogen or a hydrocarbon radical and η is an integer.

It has been found that the process for the preparation of new alkylidene dieters can be carried out advantageously if a vinyl ether is reacted with the acetal of an aldehyde or ketone having at least 3 carbon atoms in the presence of an anhydrous, acidic condensing agent, especially boron trifluoride or its diethyl ether complex compound, but other condensing agents of this type can also be used, e.g. Boron trichloride, tin chloride, titanium chloride, sulfuric acid, etc. Only small amounts of the catalyst are required, and when boron trifluoride or its diethyl ether complex compound is used, amounts of 0.0001 to 0.1 moles per mole of acetal have been found to be effective. The preferred amount of catalyst used is between 0.0025 and 0.01 mol per mol of acetal. The reaction can be carried out at temperatures from 0 to 50 ^° C., with excess pressure, if necessary, being used in order to keep all reaction components in the liquid phase. The nature of the product obtained, ie the length of the chain of the alkylidene radical therein, depends on the ratio between acetal and vinyl ether. One obtains z. B. 1,1,3-trimethoxyhexane with about o, o ° / ₀ yield, calculated on the amount of methyl vinyl ether used, when methyl vinyl ether and the dimethyl acetal of butyraldehyde are mixed in a molar ratio of about 1: 3. If the amount of vinyl ether in the reaction mixture is increased, the product becomes a mixture of alkylidene compounds with a higher molecular weight, ie the number η in the above equation becomes greater than 1.

The process according to the invention is illustrated in detail in the following examples.

_.

example 1

720 parts of diethylbutyral and 0.315 parts of boron fluoride-ether complex compound are heated in a with OR ² \

OR ² / «

Thermometer equipped glass reaction vessel at 45 ° C. and 93 parts of methyl vinyl ether in 135 minutes under stirring to the solution while maintaining a reaction temperature of 45 to 50 ⁰ C. After standing overnight, the boron fluoride catalyst is neutralized with 1 part of ethanolamine and distilled off. If unreacted Diäthylbutyral is removed, the main reaction product boils at 98 ⁰ C / 11 mm. Yield: 204 parts (63.5 ° / ₀ of theory); nl ⁵ = 1.4176; d * i = 0.8698.

Analysis for C _n H ₂₁ O ₃ : Theoretical ... C = 64.66, H = 11.84; found C = 64.70, H = 12.12.

The reaction product is (1,3-diethoxy-i-methoxyhexane):

CH3

OC. H _s

¥ OCH ₅

CH ₉ C

OC ₅ H ₅

Polyalkoxyacetals with a higher boiling point are also formed.

Example 2

258 parts (1.5 mol) of cyclohexanone diethyl ketal and 0.1 part of boron fluoride-ether complex compound are mixed with stirring and 49 parts (0.85 mol) of methyl vinyl ether are added over 90 minutes with stirring. The reaction is exothermic and the reaction mixture is kept ^{at approximately 35 ° C. by cooling.} The catalyst is then neutralized with 0.5 ecm of ethanolamine and the volatile constituents are distilled off. After unreacted cyclohexanone ketal has been removed, i-ethoxy-i - (/ 5-ethoxy - /? - methoxyethyl) cyclohexane is obtained as a clear, white liquid. Kp ₂ 79 to 81 ⁰ C. n% = 1.4448; d * $ = 0.9522.

Analysis for C ₁₃ H ₂₆ O ₃ :
Theoretically ... C = 67.79, H - * ^τ > 3 &'· found C = 68.29, H = ^ιτ > ² 9 ·

Higher bp polyalkoxyacetals are present in the reaction mixture.

Example 3

608 parts (4 mol) of dimethylbenzal and 0.25 part of boron fluoride ether complex compound are mixed and 130 parts (2.25 mol) of methyl vinyl ether are passed into the reaction mixture over 135 minutes. The reaction temperature is kept at 30 to 40 ^{° C. by cooling.} After stirring for 1 hour, the catalyst is neutralized with 1 part of ethanolamine and the mixture is distilled. The main part of the reaction product consists of 1,1,3-trimethoxy-3-phenylpropane. Kp. _Β 112 ° C. Yield: 56 ⁰ I ₀ , calculated on vinyl ether. n ^! o = 1.4830; d * f = 1.0132.

Example 4

40 parts (0.3 mol) of diethyl ketal and 0.2 part of boron fluoride are mixed and 9 parts (0.15 mol) of methyl vinyl ether are introduced. The reaction is slightly exothermic and the temperature is maintained by external cooling at 4 ⁰ C. After stirring for half an hour, the catalyst is neutralized with sodium methylate and the mixture is distilled. If unreacted ketal is removed, one obtains a 32 ° / ₀ yield of / J-methyl - ^ - äthoxybutyraldehydmethyläthylacetal. . Kp ₆₁₁₁ ⁰ C; »Ff = 1.4245.

Analysis for C ₁₀ H ₂₂ O ₃ :

Theoretically ... C = 63.11, H = 11.65; found C = 63.20; H = 11.20.

It should be noted that the above examples are only preferred embodiments of the invention Process show and that various modifications are possible.

It is evident that many new alkylidene dieters according to the invention by choosing special acetals and special vinyl ethers can be produced. Examples of other acetals of oxocarbonyl compounds, instead of diethylbutyral, cyclohexanone diethylacetal, dimethylbenzal or diethylketal can be used are dimethylpropional, dimethylisobutyral, dimethylacetal des Lauryl aldehyde, dimethyl acetal of stearyl aldehyde, cyclohexanone dimethyl acetal, acetone dimethyl acetal, Methyl ethyl ketone dimethyl acetal, phenyl acetaldehyde dimethyl acetal, acetophenone dimethyl acetal and the like. or the corresponding diethyl, dipropyl, dibutyl or other dialkyl or mixed alkyl acetals,

z. B. Methyläthylacetale u. The like. Vinyl ethers of the general formula

CHR ¹ = CR ² -0 -R

where R is a hydrocarbon radical, preferably a lower alkyl radical, and R ¹ and R ^{2 are} preferably hydrogen, but can also be hydrocarbon radicals, can be used in the process according to the invention. Examples of α, / 3-ethylene-unsaturated ethers are the methyl, ethyl, propyl, isopropyl, η-butyl, isobutyl, dodecyl, octadecyl, phenyl, cresyl and benzyl ethers of the following Λ, / 3-unsaturated alcohols: vinyl, isopropenyl, butenyl, oc-phenylvinyl and / S-phenyl vinyl alcohol. If desired, vinyl ethers such as / f-methoxyethyl vinyl ether and / J-methylthioethyl vinyl can also be used. In any case, conversion occurs according to the equation given above.

The new products can not only be used as intermediate products, but also directly for many purposes technically used. For example, they can be used in the production of adhesives, coating layers, printing inks and the like. to adjust their viscosity to the desired value and to ensure their adhesiveness and flexibility to change and regulate.

Since the new products are liquids with a relatively high boiling point, they can also be used as Solvents can be used for various purposes and as substitutes for solvents of the polyethylene glycol type Find use. They can also be used as high-boiling liquids as hydraulic Brake fluids are used and various of them are also used as synthetic lubricants.

A particularly advantageous use of the new products consists in their use as binders for fine sand, as used in combination with phenolic resins in certain molding and casting processes finds. In this casting process, sand is mixed with a phenolic resin, and the mixture is then poured around a heated metal mold. The resin is solidified by the hot metal mold and hardened, so that when removed a mold made of sand and resin is obtained, which is used as a mold for the production of metal castings can be used. Will be a small amount of the in question Compounds incorporated into the mixture of sand and phenolic resin make a much more accurate reproduction get the shape. The use of the products mentioned also results in discarding The mold is significantly reduced when the hot metal is poured into the mold.

Claims (5)

PATENT CLAIMS: i. Process for the preparation of alkylidene dieters of the formula "C- / CHR ³ -CR ⁴ \ OR ² R ¹ ' 0R ² \ 0R ² / _K in which - C is a hydrocarbon radical with ^ö Ri at least 3 carbon atoms in which R is a hydrocarbon radical and R ^{1 is} hydrogen or a hydrocarbon radical and R and R ¹ together can also form a carbocyclic ring, the R ² groups are radicals of an alcohol, R ³ and R ^{4 are} hydrogen or Can be hydrocarbon radicals and η is an integer, characterized in that a vinyl ether in the presence of an anhydrous, acidic condensing agent with a Acetal of an aldehyde or ketone with at least 3 carbon atoms is reacted. 2. Process for the preparation of alkylidene dieters of the formula R. R ¹ ' , C - (CH ₂ - C R) _n - O - lower alkyl O - ■ lower alkyl
O - lower alkyl in the C an alkyl group of at least R ¹ 3 carbon atoms, characterized in that a lower alkyl diacetyl of an aldehyde with at least 3 carbon atoms with a lower alkyl vinyl ether in the presence of an acidic one reacting condensing agent is implemented. 3. Process for the preparation of 1,1,3-trialkoxyalkanes having at least 5 alkane carbon atoms, characterized in that an alkylacetal an alkyl aldehyde having at least 3 carbon atoms with an alkyl vinyl ether in Is implemented in the presence of an acidic condensing agent. 4. Process for the preparation of i, r, 3-trialkoxyhexanes, characterized in that an alkyl acetal of butyraldehyde with an alkyl vinyl ether is reacted in the presence of an acidic condensing agent. 5. Process for the preparation of alkylidene ethers according to claim 1, characterized in that the reaction at a temperature between 0 and 100 ° C, preferably between 0 and 50 ⁰ C, is carried out. Considered publications:
U.S. Patent No. 2,165,962. © 109 632/25 7.61