CS227646B1 - Method of preparing n-substituted aminoethylesters of methacrylic acid - Google Patents

Description

The invention relates to a process for the preparation of N-substituted aminoethyl methacrylic esters of the general formula I

OH,

OHg = C - COOOHgCHg X (1), wherein X is dimethylamino, diethylamino or piperidino.

Homopolymerizaoí or copolymerizing those substances, either in the form _of quaternary salts or subsequent quaternization of the polymers, the cationic polymers are obtained with a wide range of use, particularly for the preparation of flocculating agents, antistatic agents, electroconductive layers and of a film nýoh materials for coating the pharmaceutical industry.

The most frequently used method for the preparation of the compounds of the formula I is the reesterification of esters, most often methyl esters of methacrylic acid, by the corresponding aminoalcoaols of the general formula II

X is CHgCHgOH (11) in which X denotes the same as in formula I, catalysed by base reagents, in particular alkali metals or alcoholates thereof. The disadvantage of using alkali metal alcoholates is the relatively easy addition of the alkoxide anions to the double bond, which leads to the formation of undesirable by-products. The use of alkali metals, such as sodium, is not suitable, especially on an industrial scale, from the point of view of occupational safety and is better replaced by a less risky process.

227 646

The aforementioned drawbacks are eliminated by the process for the preparation of N-substituted aminoethyl methacrylic acid esters of formula (I) by reesterification of alkyl esters, in particular methacrylic acid methyl ester, of eminoalcohols of formula (II) according to the invention. as a catalyst, useful in the form of a solution in an inert organic solvent such as benzene or toluene;

Dihydrido-bis-methosyethoxyaluminate, available as a commercial product in the form of a benzene or toluene solution (Mares, Chemical Industry 22, 411,, 1972), is a preferred re-esterification catalyst that is safe to handle on an industrial scale and is easy to handle. accurately dosed. Carrying out the reaction is essentially the same as in the reesterification of alkali metal-catalyzed or alcoholates thereof. The catalyst according to the invention is expediently used in an amount of 0.01 to 0.03 mol, based on 1 mol of the starting amino alcohol of the formula II.

The following examples illustrate the process according to the invention but do not limit it in any way.

Example 1

2- (Dimethylamino) ethyl methacrylate (Formula I, X = -H (CH 2) 4)

To 445 g (5 mol) of 2- (dimethylamino) ethanol, placed in a liquid-capped vessel, 30 ml of a 70% solution of sodium dihydro-bis-methoxyethoxyaluminate in toluene was added dropwise with stirring over 15 minutes. The temperature of the reaction mixture rises by about 10 ° C with the reaction heat, the hydrogen released during the reaction is vented to the exhaust. After stirring for 15 minutes. 6 g of phenothiazine and 1000 g (10 mol) of methyl methacrylate are added. The reaction mixture is heated to boiling with stirring and within 6 hours, the azectropiocre methanol / methyl methacrylate / m.p. 63 DEG-65 DEG C.) and finally a portion of the excess methyl methacrylate, in total about 400 to 500 ml. The reaction mixture was cooled, the precipitated precipitate was filtered off with suction on a glass filter and the low-boilers were distilled off in vacuo. The possibly precipitated fine precipitate is suctioned off with the addition of diatomaceous earth. Distillation in vacuo afforded 60-65% of a clear liquid product, m.p. 67 DEG-70 DEG C. (1.3 kPa), 95 to 96% pure (as determined by gas chromatography)

Example 2

2- (Diethylamino) ethyl methacrylate / Formula I, X = Proceed as in Example 1, with the same molar ratio of reactants. Yield: 56-65 $ (determined by gas chromatography) ·

Example 3

2- (Piperidino) ethyl methacrylate / formula I, X = - NO 5 ^H k /

To a mixture of 150 g (1.5 mol) of methyl methacrylate, 64.5 g (0.5 mol) of 2-piperidinoethanol and 0.5 g of phenothiazine was added dropwise 4 ml of a 70% sodium dihydrido-bis-methoxyethoxyaleaininate solution in toluene. Further procedure as in Example 1. Yield 60-68 of theory, b.p. 114-118 kPa, 96-96% (determined by gas chromatography).

Claims (2)

P 3 É M Ϊ VTKÁIEZU 227 646 A process for the preparation of the H-substituted aminoethyl methacrylic esters of the general formula X CEg = C - CCOCEgCEg Z (1), in which Z is dimethylamino, diethylamino or piperidino, by re-esterification of alkyl esters, in particular methyl methacrylate, amino alcohols of formula II (II) in which Z is the same as in formula I, characterized by characterized in that the re-esterification is carried out in the presence of sodium dihydrido-bis-methoxyethoxyaluminate as a catalyst; 2. The process of claim 1, wherein sodium dihydrido-bis-methoxyethoxyaluminate is used in the form of a solution in an inert organic solvent such as benzene or toluene.