DE1077872B - Process for the preparation of nitrogen-containing derivatives of polymethacrylic acid - Google Patents

Description

kl. 39c 25/01

INTERNAT. KL. C 08 f

PATENT OFFICE

R22969IVb / 39c

REGISTRATION DATE: MARCH 22, 1958

NOTICE
THE REGISTRATION
AND ISSUE OF THE
ADSLEWRITING: MARCH 17, 1960

It is known that high molecular weight polymethacrylic acid esters can be used in contrast to the corresponding Difficult to implement polyacrylates, e.g. B. saponify or transesterify, apparently because of a spatial Hindrance by the methyl in the α position. For a long time they had therefore come to terms with that polymethyl methacrylate is completely indifferent to alkalis, ammonia or alcohols. By Selection of suitable reaction conditions, primarily through the use of high temperatures, was successful later, however, polymer-analogous reactions with the macromolecular compounds mentioned perform.

In the reaction of polymethacrylic acid methyl ester with ammonia, ammonia-releasing compounds or primary amines, the teaching given in US Pat Able to split off amine, is reacted at temperatures between 140 and 250 ⁰ C, optionally with the application of pressure. The use of solvents or thinners is possible. Examples of such agents are diethylene glycol, ethylene glycol, xylene, diphenyl, etc., ie solvents that are indifferent to the reaction taking place. The use of a small amount of water (<C 1%) as a catalyst specified in Example 9 is irrelevant for the basic course of the reaction. According to the information in the patent, polymethacrylamides are formed which, according to Example 1, are soluble in formamide, diethylene glycol, dilute aqueous alkali and dilute ammonia. The reaction product can be precipitated from the alkaline solution by acidification. The fact that the products obtained by the known process are soluble in aqueous ammonia is particularly pointed out with regard to the statements below.

It has now been found that polymethyl methacrylate can be reacted with aqueous ammonia at temperatures between 180 and 300 ^° C. and the pressure established at this temperature to give products which are not identical to the polymeric compounds obtainable according to US Pat. No. 2,146,209 are. The new process results in products which are insoluble in dilute aqueous ammonia, but which are dissolved in dimethylformamide or concentrated formic acid and from such solutions z. B. can be processed into films. These are dimensionally stable up to around 230 ° C. The product obtained with the aid of the process described can be used in processes for production

Derivatives containing nitrogen

of polymethacrylic acid

Applicant:

Rohm & Haas G. mb H. _r
Darmstadt, Mainzer Str. 42

Dr. Klaus Tessmar, Darmstadt,
has been named as the inventor

about 250 ° C pressed into a solid plastic will.

It is particularly advantageous to allow the reaction of polymethyl methacrylate with ammonia in the aqueous solution of an electrolyte, e.g. B. potassium chloride or ammonium sulfate, run. That at The end product obtained in this way can be filtered, washed out and dried particularly well. the Mother liquor containing electrolytes can be used for a new approach.

The nitrogen content of the polymeric compounds obtained is on average 6.5 to 8.5%.

Their behavior towards alkalis provides information about the structure of the products prepared according to the invention. If you let z. B. aqueous sodium hydroxide solution or milk of lime at elevated temperature, e.g. B. 100 up to 150 ° C, only the smaller part of the nitrogen is split off by saponification. From it it can be concluded that the action of aqueous ammonia on polymethylmetliacrylate results in a polymer compound, some of which is arnid- or ammonium salt-like and largely imide-like bonded nitrogen contains.

By modifying the known process for the implementation of polymethyl methacrylate in such a way, that instead of ammonia or an amine and an inert solvent or diluent Lets aqueous ammonia act on the polymer, surprisingly, products are obtained which differ significantly from the compounds which can be produced by the known process.

It has already been proposed to use methyl polymethacrylate of alkaline hydrolysis at the same time Subject to presence of ammonia. With this approach, nitrogenous ones are obtained macromolecular compounds in the form of their aqueous

909 760/439

solutions. In contrast, with the help of the new method, one arrives at insoluble ones directly Solid products, which as such z. B. used for the production of films or compacts or in others, e.g. B. water-soluble products can be transferred.

The protection should not be limited to the procedure described as an example, but rather should include any method in which the polymethacrylic acid methyl ester or predominantly Share of copolymers composed of methyl methacrylate with aqueous ammonia in one Amide and imide groups containing macromolecular compound is converted.

example 1

120 g of polymethyl methacrylate in the form of milling chips made from high molecular weight block polymer (η sp / c = 0.65), 100 g of aqueous ammonia (about 35%) and 900 g of water are heated to 200 to 220 ° C for 10 hours in an autoclave. The pressure is 25 to 30 atmospheres. After cooling, 95 g of a solid, pulverizable mass can be removed from the autoclave, which is insoluble in water and the usual organic solvents, but soluble in dimethylformamide or formic acid. Their N content is 7.9% (Kjeldahl). The preparation is also insoluble in aqueous ammonia and 0.1 η sodium hydroxide solution.

Example 2

120g polymethyl methacrylate in the form of grinding dust from block polymer (?; sp / c = 0.6) are mixed with 200 g of 35% aqueous ammonia and 450 g of water Heated to 220 to 230 ° C with vigorous stirring. The pressure rises to 40 atü. Cools after 4.5 hours a white dispersion is obtained, the dry substance of which is isolated by spray drying can. It has the same chemical properties as the preparation described in Example 1 on.

In a corresponding experiment with polymethyl methacrylate powder of lower viscosity (η sp / c = 0.12), a similar dispersion is obtained.

Example 3

180 g of polymethyl methacrylate in the form of granules about 3 mm in diameter are added with 150 g aqueous ammonia (35%) and 850 ecm of water in a pressure vessel with stirring for 5 hours at 200 ° C heated.

By adding 9 g of stearic acid or 9 g of dodecyl alcohol or 9 g of a copolymer The reaction product is styrene and methacrylic acid (30:70) as the ammonium salt or 3 g of talc powder preserved in spherical, easily filterable form, and the reaction vessel remains free of difficult to remove Polymer crusts.

Example 4

100 g of coarsely crushed plate material of PoIymethylmelhacrylat be in a wire basket of V2A steel in a pressure vessel whose bottom third is filled with 20% aqueous ammonia, heated to 180 ⁰ C, in such a way that the polymer is only in the vapor space . After 3 hours it is cooled, crushed and dried. A powder is obtained which contains 8.7% N and 1.14% OCH ₃ .

Similar results are achieved both with sheet material made of pure polymethyl methacrylate as also with one that contains up to 20% methyl acrylate or butyl methacrylate as comonomer. as well Plasticizers can be contained in polymethyl methacrylate in amounts of up to 10%.

Example 5

One weighs each in pressure vessels with a capacity of 10 ecm 2 g of polymethyl methacrylate and 35% aqueous ammonia and heated:

temperature
⁰ C Time
Minutes VoOCH ₃
the dried one
prod ° / oN
: en reaction
uktes a) 250 j 15th
30th
60 28.3
1.5
0.3 b) 275 j 10
20th 28.0
3.44 0.77
6.98
8.25 0.25
6.97

Example 6

2.5 kg of a granulate of polymethyl methacrylate (η sp / c = 1.07) with a diameter of 3 to 6 mm

as is heated in a 20 l autoclave made of V2A steel with stirring with 0.55 kg ammonia (calculated on 100% NH ₃ ), 8.00 kg water and 2.00 kg potassium chloride at 210 ° C for 5 hours. This results in a pressure of 27 to 28 atmospheres. After cooling, the slightly swollen, rubber-like granulate is filtered off with suction, washed briefly with water and dried. The mother liquor can be used for a new approach.

Example 7

In a screw conveyor, which is heated to 260 to 27O ⁰ C, is pressed to polymethylmethacrylate (η sp / c is about 0.4 to 0.6) is approximately after the first third of the length of the screw at a pressure of 80 atm to 120 a Mixture of NH ₃ and H ₂ O (80:20) was added. The ammonia is absorbed and a foamy strand emerges at the mouthpiece of the screw, which is soluble in dimethylformamide after drying.

Example 8

In a stirred autoclave of 2 1 Content 400 g of polymethyl methacrylate (η sp / c = 0.85, granules of 1 to 3 mm in diameter) washed with 200 g of 30% aqueous ammonia, 700 g of water and 100 g of ammonium sulfate 7 hours to 200 ⁰ C heated. The externally unchanged granules are filtered off with suction, washed with water and dried ^{at 60 ° C. in vacuo.} N = 7.45%; ?? sp / c = 0.35 (at 40 ° C. in a mixture of 95 parts of dimethylformamide with 5 parts of formic acid).

The powder can be pressed at 250 ° C. and a pressure of 100 kg / cm ² . The plates have the following mechanical properties:

Impact strength (Dynstat)
Flexural Strength (Dynstat).
Heat resistance.

13.9 kg / cm ²
1037 kg / cm ²
200 ⁰ C

Example 9

400 g of ground polymethyl methacrylate are mixed with 89.3 g of 33.6% ammonia, 600 g of water and 150 g of potassium chloride in a 2-1 stirred autoclave during heated to 195 ° C for one hour. Then 174 g of 33.6% ammonia are obtained in the course of 3 hours with the help of a Bosch injection pump into the

Autoclave and the mixture was stirred at 190 to 192 ° C for a further 4 hours. The reaction product has retained the form of the polymer originally used, but contains nitrogen and is soluble in dimethylformamide (η sp / c = 0.6, measured in a mixture of 95 parts of dimethylformamide with 5 parts of formic acid). The nitrogen content of the dried reaction product is 7.0%.

Claims (2)

Patent claims: 1. Process for the preparation of nitrogen-containing derivatives of polymethacrylic acid from Polymethyl methacrylate or composed predominantly of methyl methacrylate Copolymers by reaction with ammonia, characterized in that on polymethyl methacrylate aqueous ammonia at temperatures from 180 to 300 ° C under pressure for action comes. 2. The method according to claim 1, characterized in that said reaction in the presence an electrolyte is carried out. Considered publications:
U.S. Patent No. 2,146,209.