CS215801B1 - Production of aldehyde derivatives of polystyrene - Google Patents

Abstract

The invention relates to the preparation of polymers and copolymers of styrene carrying aldehyde groups. The essence of the invention is a method for the production of aldehyde derivatives of linear and crosslinked polymers or copolymers of styrene, which consists in treating a linear or crosslinked polymer or copolymer of styrene with dichloromethyl alkyl ether, where the alkyl has 1-4 C atoms, in the presence of a Friedel-Crafts catalyst. Suitable Friedel-Crafts catalysts are tin tetrachloride, titanium tetrachloride and aluminum chloride. Aldehyde derivatives of styrene polymers serve as starting materials in the preparation of functionalized polystyrenes.

Description

The invention relates to the preparation of polymers and copolymers of styrene bearing aldehyde groups.

Aldehydes are common starting materials in organic synthesis. The use of ipol (vinyl benzaldehyde) as a starting material in the preparation of functionalized polystyrenes does not yet correspond to the possibilities provided by the reactive aldehyde group. One of the possible causes is not very satisfactory methods of its preparation.

Essentially, only three methods for preparing poly (vinyl benzaldehyde) are described in the literature: monomer polymerization, polystyrene lithium reaction with dimethylformamide and oxidation of poly (vinyl benzyl chloride) with dimethylsulfoxide. None of these methods is satisfactory. The preparation of the monomer is tedious, the preparation of the polythyrene is difficult and requires a special technique. Frequently used oxidation with dimethylsulfoxide is not smooth and provides a non-uniform product. In addition, even small amounts of water in the reaction mixture lead to the hydrolysis of the chlorodallate, which is extremely facilitated by the dimethylsulfoxide environment, i.e. the inhomogeneous product. Last but not least, it should be noted that this method of preparation produces intensely odorous dlmethylsulfide. Thus, the preparation of aldehyde derivatives of polystyrene by a one-step polymer-analogous reaction, which only can provide a homogeneous product, i.e. a product with only one kind of functional groups, has not been described.

SUMMARY OF THE INVENTION The present invention provides a process for the preparation of aldehyde derivatives of styrene polymers by direct one-step synthesis - formylation of the styrenic polymer with alkyl-dichloromethyl ether in the presence of a Friedel-Crafts catalyst.

According to the process of the invention, soluble linear poles (vinylbenzaldehyde) 1 aldehyde derivatives of crosslinked polystyrenes, e.g. styrene-divinylbenzene copolymer; both gel and macroporous copolymers can be used. It is also possible in this way to introduce the aldehyde group into a number of other styrene copolymers. The formulating agent is dichloromethyl-alkyl ethers of any alkyl; ethers with C1-C4 alkyls are preferred. Various Friedel-Crafts catalysts may be used as the catalyst; tin tetrachloride, titanium tetrachloride are preferred. aluminum chloride.

The production of poly (vinylbenzaldehydes) according to the invention is simple, provides high conversions and leads to uniform products.

Example 1

To 7.5 g of styrene-2% divinylbenzene swollen in 55 ml of methylene chloride was added 39 g of anhydrous tin (II) chloride and 7.4 g of methyl-dichloro-methylether under cooling. After stirring at room temperature for four hours, aspirate and wash sequentially with 1,4: dloxane-water 3: 1, 1,4-dioxane-6N HCl 3: 1 and 1,4-dioxane and dried.

Infrared spectra confirm the presence of the aldehyde group. The aldehyde content is greater than 3.6 mmol / g (determined by oximation).

Example 2

7.5 g of dried styrene-divinylbenzene copolymer (Amberlite. XAD-2, manufactured by Rohm-Haas) were dried in the same manner as in Example 1. Infrared spectra confirm the presence of the aldehyde group; the aldehyde content is greater than 1.5 mmol / g (determined by oximation).

Claims (2)

SUBJECT Process for the production of aldehyde derivatives of linear and crosslinked polymers or copolymers of styrene, characterized in that the linear or crosslinked polymer or styrene copolymer is treated with a dichloromethyl-alkyl ether, wherein the alkyl has YNALEZU 1-4 C atoms in the presence of Friedel-Crafts catalyst. 2. The process according to claim 1, wherein the Friedel-Crafts catalysts used are tin tetrachloride, titanium tetrachloride and aluminum chloride.