DE1004185B - Process for the preparation of polymerizable, amide-like compounds - Google Patents

Description

It has been found that polymerizable, amide-like compounds are obtained if urea is used or melamine with formaldehyde or paraformaldehyde and with acrylonitrile in the presence of concentrated Reacts sulfuric acid as a condensing agent. The condensation can take place at low temperatures, e.g. B. be carried out at about 0 °, or at elevated temperatures. Preferably at temperatures condensed between 5 and 40 °.

The concentrated sulfuric acid is advantageously added in excess. Optionally, the reaction mixture an organic inert solvent such as tetrahydrofuran or glacial acetic acid is also added will.

The formaldehyde is expediently used in the form of a concentrated aqueous solution.

When the condensation has ended, the reaction mixture is advantageously poured into water and the free Sulfuric acid neutralized. The polymerizable amide-like condensation products formed can then be deposited by filtration or by Extraction can be obtained with an organic solvent.

The choice of the proportions between the individual reaction components depends on which Properties you want to give the end product. If amide-like products that are only polymerizable are are generated, so you have to z. B. 1 mole of melamine or urea with 1 mole of formaldehyde and 1 mole of acrylonitrile react in the presence of sulfuric acid. If the aim is to produce amide-like compounds, which, in addition to being able to polymerize, are also condensable, d. H. are hardenable, they have to be Choose proportions between the reaction components so that at least one free methylol group in the End product remains, or has to introduce further methylol groups into the end product.

The polymerization or copolymerization of the compounds accessible according to the invention takes place under the usual conditions.

It is known that from certain monocarboxylic acid N-methylolamides and acrylonitrile in the presence of acidic condensing agents acrylamidomethylene carboxamides can be prepared (see U.S. Pat. No. 2,529,455, also Journal of the American Chemical Society Vol. 73, pp. 1035 to 1037 [1951], and Vol. 69, pp. 254 to 256 [1947]). If you try in appropriate Way N-methylol compounds of the urea or aminotriazine series and acrylonitrile with each other implement, this gives mixtures of more or less polycondensed compounds. Surprisingly, however, the present process gives monomeric, crystallizable end products.

procedure

for the production of polymerizable, amide-like compounds

Applicant:
CIBA Aktiengesellschaft, Basel (Switzerland)

Representative: Dipl.-Ing. E. Splanemann, patent attorney,
Hamburg 36, Neuer Wall 10

Claimed priority:
Switzerland from November 26, 1952

Dr. Daniel Porret and Dr. Ernst Leumann,

Monthey (Switzerland),
have been named as inventors

In the following examples, parts mean parts by weight, unless otherwise noted.

example 1

Is added with cooling and stirring to 300 parts of concentrated sulfuric acid, 57 parts of 40 ° / ₀ aqueous formaldehyde solution and then over 20 minutes, 95 parts of melamine, wherein the temperature is between 5 and 15 ° is maintained. 41 parts of acrylonitrile are then allowed to flow in over 15 minutes, the temperature of the reaction mixture being allowed to rise to 40 ° and then kept at this temperature by cooling. After the end of the entry, stirring is continued for 3 hours at ordinary temperature and the mixture is then poured onto ice. The sulfuric acid is carefully neutralized with sodium hydroxide solution and the precipitate is filtered off. After drying, 75 parts of a white powder which can be easily polymerized and which essentially corresponds to a melamine monomethylene acrylamide are obtained.

The condensation product can be made completely water-soluble by introducing methylol groups which is expediently carried out in a weakly alkaline aqueous solution. The water-soluble methylol compound can be obtained from the aqueous solution by spray drying.

Example 2

In a suitable stirred vessel, the solution is dissolved in 1000 parts of 98% strength sulfuric acid by adding in portions

609 839/391

Claims (3)

3 ⁴ gradually 150 parts of finely ground paraformaldehyde. initially in a weak vacuum, later after expulsion It is permissible to keep the temperature of the acetone up to about 70 ° at · 14 mm. Begins in the distillation flask to let rise. When everything is dissolved, one then slowly cools the excretion of the acrylamido-methy mixture and wears off, always with good stirring, with len-urea. You suck off the product and win 10 to 20 ° 300 parts of finely ground urea slowly 5 from the mother liquor by further concentration a. After the addition of the urea has ended, the further portion is stirred. Obtained recrystallized from alcohol still about After 3 hours at 10 ° to 20 °, 160 parts of acrylamido-methylenourea are finally allowed to drip into the clear solution of 265 parts of acrylonitrile. In the form of coarse prisms that melt at 130 to 131 °, there is only a weak development of heat, and acrylamide can be separated from the mother liquor of the crude product by occasional cooling by occasional cooling at 0.03 mm distillation,
below 35 °. In total, the mixture is then stirred at room temperature for a further 15 hours and then the patent claim
clear reaction mixture on ice, with only a slight evolution of heat taking place. Thereupon the neutral process for the production of polymerizable is siert with 50% sodium hydroxide solution with cooling, so that 15 amide-like products, characterized in that the temperature does not rise significantly above 10 °. After melamine or urea with formaldehyde or complete neutralization, the precipitated paraformaldehyde and acrylonitrile are filtered off in the presence of sodium sulfate and washed with hot acetone from concentrated sulfuric acid, which is preferably collected separately with the acetone. The aqueous solution is added in excess, and the filtrate is freed as the condensing agent and the largest 20 is then reacted in vacuo at 40 °. Part of the water and filtered again from the excreted demineralized sodium sulfate. The latter is combined with the publications previously considered: reserved wash acetone and British aqueous patent specification No. 683,918; Solution and the acetone solution evaporated together, U.S. Patents No. 2,640,041, 2,529,455. © 609 839/391 3.57