CS239500B1 - Process for preparing polymers with reactive anhydride groups - Google Patents

Abstract

The method of preparing polymers with reactive anhydride groups consists in heating a copolymer of acrylic acid, methacrylic acid or their nitriles or esters with 2 to 40 wt. » of divinyl monomer directly or after hydrolysis under reduced partial pressure in a stream of inert gas to a temperature of 200' to 290 °C for a period not exceeding 100 minutes. The advantage is the simple implementation of thermal dehydration in a stream of inert gas and further the preferred formation of cyclic anhydrides located predominantly in the surface layer of the polymer

Description

The invention relates to a process for the preparation of polymers with reactive anhydride groups.

Polymers with reactive groups are useful as intermediates for the introduction of ligands with sorption-active, catalytic or biological activity. One of the reactive groups with sufficient reactivity suitable for mild conditions and for binding of biologically active substances - enzymes, antigens, etc. are anhydride groups. Polymers with such kind of groups were most commonly prepared by copolymerization of, for example, maleic anhydride, which had the disadvantage that the reactive groups were distributed throughout the bulk of the polymer (Ooddrich Co. Erf .; RM Summers: US Pat. 2,967,175 (1958) and Monsanto Chemical Co. British Pat 815 821 (1958), Monsanto Chemical Co. Erf .: RM Hedrlck, JA Herbig: Oer Pat 1, 09 373 (1956)

The present invention relates to a process for the preparation of polymers with reactive anhydride groups, comprising the step of forming a copolymer of acrylic acid, methacrylic acid or their nitriles or esters with 2-40 wt. % of the divinylic monomer are heated, directly or after hydrolysis, under reduced partial pressure in an inert gas stream to a temperature of 200 to 290 ° C for a period not exceeding 100 minutes.

According to the invention, it is possible to prepare polymers with anhydrite groups in high concentration in the surface layer by subsequent chemical conversion of copolymers of esters and nitriles of acrylic acid and methacrylic acid. Highly cross-linked macroporous type polymers are best suited to the process of the invention. According to the invention, polymers having a wide variety of anhydride groups can be prepared by a simple process. Copolymers of esters or nitriles of acrylic or methacrylic acid which have been hydrolyzed to acrylic or methacrylic acid copolymers by treatment with 2-9 mol / l sodium hydroxide (NaOH) for 0.5 to 2 hours at 80 to 130 ° C are most suitable for the preparation. . 241,727 of the desired degree. As is well known, the reaction proceeds in microblocks, thereby creating places in the polymer with a clear disposition to close the six-membered preferred anhydride rings.

Such a result cannot be achieved when starting from copolymers of monomeric acids since the occurrence of carboxyl groups in the chains is random, thereby reducing the likelihood of cyclic enhydride formation. For the actual formation of anhydrides, the copolymers and the carboxyl groups in the H form are particularly suitable.

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It is advantageous to use acrylic or methacrylic acid copolymers prepared by hydrolysis. Such copolymers form cyclic anhydrides detectable by infrared spectroscopy - by the presence of a selective band at 1800 cm @ -1.

Anhydrites are best obtained from polymeric acids (0.6 mmol anhydride groups / g polymer); however, they can also be prepared by direct thermal dehydration of sodium salts of polymeric acids or polymeric esters. However, the reaction proceeds less readily (0.2 mmol anhydride groups / g polymer).

The higher effect of the invention is in comparison with the present state of the art in a simple embodiment of thermal dehydration in an inert gas stream and furthermore preferred to form cyclic anhydrides situated predominantly in the polymer surface layer.

The present invention is characterized by the following non-limiting examples.

EXAMPLE 1 Part of a macroporous pole (2,3-dihydroxypropyl methacrylate-co-ethylenedimethacrylate) by mass. 5 parts of sodium hydroxide (NaOH) in water-ethylene glycol monomethyl ether (1: 2.75) was added and heated for 30 minutes at 20 ° C. An intermediate was obtained which contained 2.65 mmol of COOK & groups / g. The polymer was converted to H form by washing with 25 parts of 1 mol / L hydrochloric acid (HCl) and 50 dttly distilled water and dried.

239900

Thermal dehydration of the polymer was carried out in a column type reactor. The polymer was heated to 270 ° C under a stream of nitrogen for 20 minutes. The product contained 0.98 mmol of anhydride groups / g, corresponding to 5 wt. *. The infrared spectra of the product were measured KBr present medium intensity band at 1800 cm ^'1. Example 2

The polymer of Example 1 in the Na form dehydrated under the same conditions contained 0.2 mmol of anhydride groups / g of polymer. There was an observable band at 1,800 cm in spectra.

EXAMPLE 3 A part of 2,3-dihydroxypropyl methacrylate-ethylenedimethacrylate copolymer heated to 270 DEG C. in a stream of nitrogen for 20 minutes contained 0.2 mmol of anhydride groups / g of polymer. The spectra showed an observable band at 1800 cm.

Example 4

One part of the acrylonitrile-ethylene dimethacrylate copolymers was overlaid with 5 parts of nitric acid and allowed to react at 50 ° C for 0 hours. The product was washed with water until the acidic reaction disappeared. In a reactor filled with hydrolyzed polymer, the temperature was increased to 200 ° C for 1 hour and then to 290 ° C for 0 minutes under inert gas flow.

The anhydride content of 0.32 mmol / g was found by volumetric determination.

Claims (1)

REFLECT THE INVENTION A process for the preparation of copolymers with anhydride groups, characterized in that the copolymer of acrylic, methacrylic acid or their nitriles, iles or esters and 2-40 wt. % of the divinylic monomer are heated, directly or after hydrolysis, under reduced partial pressure in an inert gas stream to a temperature of 200 to 290 ° C for a period not exceeding 100 minutes.